root/kernel/events/core.c

DEFINITIONS

1. remote_function
2. task_function_call
3. cpu_function_call
4. __get_cpu_context
5. perf_ctx_lock
6. perf_ctx_unlock
7. is_kernel_event
8. event_function
9. event_function_call
10. event_function_local
11. update_perf_cpu_limits
12. perf_proc_update_handler
13. perf_cpu_time_max_percent_handler
14. perf_duration_warn
15. perf_sample_event_took
16. perf_event_print_debug
17. perf_pmu_name
18. perf_clock
19. perf_event_clock
20. __perf_effective_state
21. __perf_update_times
22. perf_event_update_time
23. perf_event_update_sibling_time
24. perf_event_set_state
25. perf_cgroup_match
26. perf_detach_cgroup
27. is_cgroup_event
28. perf_cgroup_event_time
29. __update_cgrp_time
30. update_cgrp_time_from_cpuctx
31. update_cgrp_time_from_event
32. perf_cgroup_set_timestamp
33. perf_cgroup_switch
34. perf_cgroup_sched_out
35. perf_cgroup_sched_in
36. perf_cgroup_connect
37. perf_cgroup_set_shadow_time
38. list_update_cgroup_event
39. perf_cgroup_match
40. perf_detach_cgroup
41. is_cgroup_event
42. update_cgrp_time_from_event
43. update_cgrp_time_from_cpuctx
44. perf_cgroup_sched_out
45. perf_cgroup_sched_in
46. perf_cgroup_connect
47. perf_cgroup_set_timestamp
48. perf_cgroup_switch
49. perf_cgroup_set_shadow_time
50. perf_cgroup_event_time
51. list_update_cgroup_event
52. perf_mux_hrtimer_handler
53. __perf_mux_hrtimer_init
54. perf_mux_hrtimer_restart
55. perf_pmu_disable
56. perf_pmu_enable
57. perf_event_ctx_activate
58. perf_event_ctx_deactivate
59. get_ctx
60. free_ctx
61. put_ctx
62. perf_event_ctx_lock_nested
63. perf_event_ctx_lock
64. perf_event_ctx_unlock
65. unclone_ctx
66. perf_event_pid_type
67. perf_event_pid
68. perf_event_tid
69. primary_event_id
70. perf_lock_task_context
71. perf_pin_task_context
72. perf_unpin_context
73. update_context_time
74. perf_event_time
75. get_event_type
76. init_event_group
77. get_event_groups
78. perf_event_groups_init
79. perf_event_groups_less
80. perf_event_groups_insert
81. add_event_to_groups
82. perf_event_groups_delete
83. del_event_from_groups
84. perf_event_groups_first
85. perf_event_groups_next
86. list_add_event
87. perf_event__state_init
88. __perf_event_read_size
89. __perf_event_header_size
90. perf_event__header_size
91. perf_event__id_header_size
92. perf_event_validate_size
93. perf_group_attach
94. list_del_event
95. perf_aux_output_match
96. perf_put_aux_event
97. perf_get_aux_event
98. perf_group_detach
99. is_orphaned_event
100. __pmu_filter_match
101. pmu_filter_match
102. event_filter_match
103. event_sched_out
104. group_sched_out
105. __perf_remove_from_context
106. perf_remove_from_context
107. __perf_event_disable
108. _perf_event_disable
109. perf_event_disable_local
110. perf_event_disable
111. perf_event_disable_inatomic
112. perf_set_shadow_time
113. event_sched_in
114. group_sched_in
115. group_can_go_on
116. add_event_to_ctx
117. task_ctx_sched_out
118. perf_event_sched_in
119. ctx_resched
120. perf_pmu_resched
121. __perf_install_in_context
122. perf_install_in_context
123. __perf_event_enable
124. _perf_event_enable
125. perf_event_enable
126. __perf_event_stop
127. perf_event_stop
128. perf_event_addr_filters_sync
129. _perf_event_refresh
130. perf_event_refresh
131. perf_event_modify_breakpoint
132. perf_event_modify_attr
133. ctx_sched_out
134. context_equiv
135. __perf_event_sync_stat
136. perf_event_sync_stat
137. perf_event_context_sched_out
138. perf_sched_cb_dec
139. perf_sched_cb_inc
140. perf_pmu_sched_task
141. __perf_event_task_sched_out
142. cpu_ctx_sched_out
143. visit_groups_merge
144. pinned_sched_in
145. flexible_sched_in
146. ctx_pinned_sched_in
147. ctx_flexible_sched_in
148. ctx_sched_in
149. cpu_ctx_sched_in
150. perf_event_context_sched_in
151. __perf_event_task_sched_in
152. perf_calculate_period
153. perf_adjust_period
154. perf_adjust_freq_unthr_context
155. rotate_ctx
156. ctx_event_to_rotate
157. perf_rotate_context
158. perf_event_task_tick
159. event_enable_on_exec
160. perf_event_enable_on_exec
161. __perf_event_read_cpu
162. __perf_event_read
163. perf_event_count
164. perf_event_read_local
165. perf_event_read
166. __perf_event_init_context
167. alloc_perf_context
168. find_lively_task_by_vpid
169. find_get_context
170. free_event_rcu
171. detach_sb_event
172. is_sb_event
173. unaccount_pmu_sb_event
174. unaccount_event_cpu
175. unaccount_freq_event_nohz
176. unaccount_freq_event
177. unaccount_event
178. perf_sched_delayed
179. exclusive_event_init
180. exclusive_event_destroy
181. exclusive_event_match
182. exclusive_event_installable
183. _free_event
184. free_event
185. perf_remove_from_owner
186. put_event
187. perf_event_release_kernel
188. perf_release
189. __perf_event_read_value
190. perf_event_read_value
191. __perf_read_group_add
192. perf_read_group
193. perf_read_one
194. is_event_hup
195. __perf_read
196. perf_read
197. perf_poll
198. _perf_event_reset
199. perf_event_for_each_child
200. perf_event_for_each
201. __perf_event_period
202. perf_event_check_period
203. perf_event_period
204. perf_fget_light
205. _perf_ioctl
206. perf_ioctl
207. perf_compat_ioctl
208. perf_event_task_enable
209. perf_event_task_disable
210. perf_event_index
211. calc_timer_values
212. perf_event_init_userpage
213. arch_perf_update_userpage
214. perf_event_update_userpage
215. perf_mmap_fault
216. ring_buffer_attach
217. ring_buffer_wakeup
218. ring_buffer_get
219. ring_buffer_put
220. perf_mmap_open
221. perf_mmap_close
222. perf_mmap
223. perf_fasync
224. perf_event_fasync
225. perf_event_wakeup
226. perf_pending_event_disable
227. perf_pending_event
228. perf_register_guest_info_callbacks
229. perf_unregister_guest_info_callbacks
230. perf_output_sample_regs
231. perf_sample_regs_user
232. perf_sample_regs_intr
233. perf_ustack_task_size
234. perf_sample_ustack_size
235. perf_output_sample_ustack
236. __perf_event_header__init_id
237. perf_event_header__init_id
238. __perf_event__output_id_sample
239. perf_event__output_id_sample
240. perf_output_read_one
241. perf_output_read_group
242. perf_output_read
243. perf_output_sample
244. perf_virt_to_phys
245. perf_callchain
246. perf_prepare_sample
247. __perf_event_output
248. perf_event_output_forward
249. perf_event_output_backward
250. perf_event_output
251. perf_event_read_event
252. perf_iterate_ctx
253. perf_iterate_sb_cpu
254. perf_iterate_sb
255. perf_event_addr_filters_exec
256. perf_event_exec
257. __perf_event_output_stop
258. __perf_pmu_output_stop
259. perf_pmu_output_stop
260. perf_event_task_match
261. perf_event_task_output
262. perf_event_task
263. perf_event_fork
264. perf_event_comm_match
265. perf_event_comm_output
266. perf_event_comm_event
267. perf_event_comm
268. perf_event_namespaces_match
269. perf_event_namespaces_output
270. perf_fill_ns_link_info
271. perf_event_namespaces
272. perf_event_mmap_match
273. perf_event_mmap_output
274. perf_event_mmap_event
275. perf_addr_filter_match
276. perf_addr_filter_vma_adjust
277. __perf_addr_filters_adjust
278. perf_addr_filters_adjust
279. perf_event_mmap
280. perf_event_aux_event
281. perf_log_lost_samples
282. perf_event_switch_match
283. perf_event_switch_output
284. perf_event_switch
285. perf_log_throttle
286. perf_event_ksymbol_match
287. perf_event_ksymbol_output
288. perf_event_ksymbol
289. perf_event_bpf_match
290. perf_event_bpf_output
291. perf_event_bpf_emit_ksymbols
292. perf_event_bpf_event
293. perf_event_itrace_started
294. perf_log_itrace_start
295. __perf_event_account_interrupt
296. perf_event_account_interrupt
297. __perf_event_overflow
298. perf_event_overflow
299. perf_swevent_set_period
300. perf_swevent_overflow
301. perf_swevent_event
302. perf_exclude_event
303. perf_swevent_match
304. swevent_hash
305. __find_swevent_head
306. find_swevent_head_rcu
307. find_swevent_head
308. do_perf_sw_event
309. perf_swevent_get_recursion_context
310. perf_swevent_put_recursion_context
311. ___perf_sw_event
312. __perf_sw_event
313. perf_swevent_read
314. perf_swevent_add
315. perf_swevent_del
316. perf_swevent_start
317. perf_swevent_stop
318. swevent_hlist_deref
319. swevent_hlist_release
320. swevent_hlist_put_cpu
321. swevent_hlist_put
322. swevent_hlist_get_cpu
323. swevent_hlist_get
324. sw_perf_event_destroy
325. perf_swevent_init
326. perf_tp_filter_match
327. perf_tp_event_match
328. perf_trace_run_bpf_submit
329. perf_tp_event
330. tp_perf_event_destroy
331. perf_tp_event_init
332. perf_kprobe_event_init
333. perf_uprobe_event_init
334. perf_tp_register
335. perf_event_free_filter
336. bpf_overflow_handler
337. perf_event_set_bpf_handler
338. perf_event_free_bpf_handler
339. perf_event_set_bpf_handler
340. perf_event_free_bpf_handler
341. perf_event_is_tracing
342. perf_event_set_bpf_prog
343. perf_event_free_bpf_prog
344. perf_tp_register
345. perf_event_free_filter
346. perf_event_set_bpf_prog
347. perf_event_free_bpf_prog
348. perf_bp_event
349. perf_addr_filter_new
350. free_filters_list
351. perf_addr_filters_splice
352. perf_addr_filter_apply
353. perf_event_addr_filters_apply
354. perf_event_parse_addr_filter
355. perf_event_set_addr_filter
356. perf_event_set_filter
357. perf_swevent_hrtimer
358. perf_swevent_start_hrtimer
359. perf_swevent_cancel_hrtimer
360. perf_swevent_init_hrtimer
361. cpu_clock_event_update
362. cpu_clock_event_start
363. cpu_clock_event_stop
364. cpu_clock_event_add
365. cpu_clock_event_del
366. cpu_clock_event_read
367. cpu_clock_event_init
368. task_clock_event_update
369. task_clock_event_start
370. task_clock_event_stop
371. task_clock_event_add
372. task_clock_event_del
373. task_clock_event_read
374. task_clock_event_init
375. perf_pmu_nop_void
376. perf_pmu_nop_txn
377. perf_pmu_nop_int
378. perf_event_nop_int
379. perf_pmu_start_txn
380. perf_pmu_commit_txn
381. perf_pmu_cancel_txn
382. perf_event_idx_default
383. find_pmu_context
384. free_pmu_context
385. nr_addr_filters_show
386. type_show
387. perf_event_mux_interval_ms_show
388. perf_event_mux_interval_ms_store
389. pmu_dev_release
390. pmu_dev_alloc
391. perf_pmu_register
392. perf_pmu_unregister
393. has_extended_regs
394. perf_try_init_event
395. perf_init_event
396. attach_sb_event
397. account_pmu_sb_event
398. account_event_cpu
399. account_freq_event_nohz
400. account_freq_event
401. account_event
402. perf_event_alloc
403. perf_copy_attr
404. perf_event_set_output
405. mutex_lock_double
406. perf_event_set_clock
407. __perf_event_ctx_lock_double
408. SYSCALL_DEFINE5
409. perf_event_create_kernel_counter
410. perf_pmu_migrate_context
411. sync_child_event
412. perf_event_exit_event
413. perf_event_exit_task_context
414. perf_event_exit_task
415. perf_free_event
416. perf_event_free_task
417. perf_event_delayed_put
418. perf_event_get
419. perf_get_event
420. perf_event_attrs
421. inherit_event
422. inherit_group
423. inherit_task_group
424. perf_event_init_context
425. perf_event_init_task
426. perf_event_init_all_cpus
427. perf_swevent_init_cpu
428. __perf_event_exit_context
429. perf_event_exit_cpu_context
430. perf_event_exit_cpu_context
431. perf_event_init_cpu
432. perf_event_exit_cpu
433. perf_reboot
434. perf_event_init
435. perf_event_sysfs_show
436. perf_event_sysfs_init
437. perf_cgroup_css_alloc
438. perf_cgroup_css_free
439. __perf_cgroup_move
440. perf_cgroup_attach

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Performance events core code:
   4  *
   5  *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
   6  *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
   7  *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
   8  *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
   9  */
  10 
  11 #include <linux/fs.h>
  12 #include <linux/mm.h>
  13 #include <linux/cpu.h>
  14 #include <linux/smp.h>
  15 #include <linux/idr.h>
  16 #include <linux/file.h>
  17 #include <linux/poll.h>
  18 #include <linux/slab.h>
  19 #include <linux/hash.h>
  20 #include <linux/tick.h>
  21 #include <linux/sysfs.h>
  22 #include <linux/dcache.h>
  23 #include <linux/percpu.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/reboot.h>
  26 #include <linux/vmstat.h>
  27 #include <linux/device.h>
  28 #include <linux/export.h>
  29 #include <linux/vmalloc.h>
  30 #include <linux/hardirq.h>
  31 #include <linux/rculist.h>
  32 #include <linux/uaccess.h>
  33 #include <linux/syscalls.h>
  34 #include <linux/anon_inodes.h>
  35 #include <linux/kernel_stat.h>
  36 #include <linux/cgroup.h>
  37 #include <linux/perf_event.h>
  38 #include <linux/trace_events.h>
  39 #include <linux/hw_breakpoint.h>
  40 #include <linux/mm_types.h>
  41 #include <linux/module.h>
  42 #include <linux/mman.h>
  43 #include <linux/compat.h>
  44 #include <linux/bpf.h>
  45 #include <linux/filter.h>
  46 #include <linux/namei.h>
  47 #include <linux/parser.h>
  48 #include <linux/sched/clock.h>
  49 #include <linux/sched/mm.h>
  50 #include <linux/proc_ns.h>
  51 #include <linux/mount.h>
  52 
  53 #include "internal.h"
  54 
  55 #include <asm/irq_regs.h>
  56 
  57 typedef int (*remote_function_f)(void *);
  58 
  59 struct remote_function_call {
  60         struct task_struct      *p;
  61         remote_function_f       func;
  62         void                    *info;
  63         int                     ret;
  64 };
  65 
  66 static void remote_function(void *data)
  67 {
  68         struct remote_function_call *tfc = data;
  69         struct task_struct *p = tfc->p;
  70 
  71         if (p) {
  72                 /* -EAGAIN */
  73                 if (task_cpu(p) != smp_processor_id())
  74                         return;
  75 
  76                 /*
  77                  * Now that we're on right CPU with IRQs disabled, we can test
  78                  * if we hit the right task without races.
  79                  */
  80 
  81                 tfc->ret = -ESRCH; /* No such (running) process */
  82                 if (p != current)
  83                         return;
  84         }
  85 
  86         tfc->ret = tfc->func(tfc->info);
  87 }
  88 
  89 /**
  90  * task_function_call - call a function on the cpu on which a task runs
  91  * @p:          the task to evaluate
  92  * @func:       the function to be called
  93  * @info:       the function call argument
  94  *
  95  * Calls the function @func when the task is currently running. This might
  96  * be on the current CPU, which just calls the function directly.  This will
  97  * retry due to any failures in smp_call_function_single(), such as if the
  98  * task_cpu() goes offline concurrently.
  99  *
 100  * returns @func return value or -ESRCH when the process isn't running
 101  */
 102 static int
 103 task_function_call(struct task_struct *p, remote_function_f func, void *info)
 104 {
 105         struct remote_function_call data = {
 106                 .p      = p,
 107                 .func   = func,
 108                 .info   = info,
 109                 .ret    = -EAGAIN,
 110         };
 111         int ret;
 112 
 113         for (;;) {
 114                 ret = smp_call_function_single(task_cpu(p), remote_function,
 115                                                &data, 1);
 116                 ret = !ret ? data.ret : -EAGAIN;
 117 
 118                 if (ret != -EAGAIN)
 119                         break;
 120 
 121                 cond_resched();
 122         }
 123 
 124         return ret;
 125 }
 126 
 127 /**
 128  * cpu_function_call - call a function on the cpu
 129  * @func:       the function to be called
 130  * @info:       the function call argument
 131  *
 132  * Calls the function @func on the remote cpu.
 133  *
 134  * returns: @func return value or -ENXIO when the cpu is offline
 135  */
 136 static int cpu_function_call(int cpu, remote_function_f func, void *info)
 137 {
 138         struct remote_function_call data = {
 139                 .p      = NULL,
 140                 .func   = func,
 141                 .info   = info,
 142                 .ret    = -ENXIO, /* No such CPU */
 143         };
 144 
 145         smp_call_function_single(cpu, remote_function, &data, 1);
 146 
 147         return data.ret;
 148 }
 149 
 150 static inline struct perf_cpu_context *
 151 __get_cpu_context(struct perf_event_context *ctx)
 152 {
 153         return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
 154 }
 155 
 156 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
 157                           struct perf_event_context *ctx)
 158 {
 159         raw_spin_lock(&cpuctx->ctx.lock);
 160         if (ctx)
 161                 raw_spin_lock(&ctx->lock);
 162 }
 163 
 164 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
 165                             struct perf_event_context *ctx)
 166 {
 167         if (ctx)
 168                 raw_spin_unlock(&ctx->lock);
 169         raw_spin_unlock(&cpuctx->ctx.lock);
 170 }
 171 
 172 #define TASK_TOMBSTONE ((void *)-1L)
 173 
 174 static bool is_kernel_event(struct perf_event *event)
 175 {
 176         return READ_ONCE(event->owner) == TASK_TOMBSTONE;
 177 }
 178 
 179 /*
 180  * On task ctx scheduling...
 181  *
 182  * When !ctx->nr_events a task context will not be scheduled. This means
 183  * we can disable the scheduler hooks (for performance) without leaving
 184  * pending task ctx state.
 185  *
 186  * This however results in two special cases:
 187  *
 188  *  - removing the last event from a task ctx; this is relatively straight
 189  *    forward and is done in __perf_remove_from_context.
 190  *
 191  *  - adding the first event to a task ctx; this is tricky because we cannot
 192  *    rely on ctx->is_active and therefore cannot use event_function_call().
 193  *    See perf_install_in_context().
 194  *
 195  * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
 196  */
 197 
 198 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
 199                         struct perf_event_context *, void *);
 200 
 201 struct event_function_struct {
 202         struct perf_event *event;
 203         event_f func;
 204         void *data;
 205 };
 206 
 207 static int event_function(void *info)
 208 {
 209         struct event_function_struct *efs = info;
 210         struct perf_event *event = efs->event;
 211         struct perf_event_context *ctx = event->ctx;
 212         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
 213         struct perf_event_context *task_ctx = cpuctx->task_ctx;
 214         int ret = 0;
 215 
 216         lockdep_assert_irqs_disabled();
 217 
 218         perf_ctx_lock(cpuctx, task_ctx);
 219         /*
 220          * Since we do the IPI call without holding ctx->lock things can have
 221          * changed, double check we hit the task we set out to hit.
 222          */
 223         if (ctx->task) {
 224                 if (ctx->task != current) {
 225                         ret = -ESRCH;
 226                         goto unlock;
 227                 }
 228 
 229                 /*
 230                  * We only use event_function_call() on established contexts,
 231                  * and event_function() is only ever called when active (or
 232                  * rather, we'll have bailed in task_function_call() or the
 233                  * above ctx->task != current test), therefore we must have
 234                  * ctx->is_active here.
 235                  */
 236                 WARN_ON_ONCE(!ctx->is_active);
 237                 /*
 238                  * And since we have ctx->is_active, cpuctx->task_ctx must
 239                  * match.
 240                  */
 241                 WARN_ON_ONCE(task_ctx != ctx);
 242         } else {
 243                 WARN_ON_ONCE(&cpuctx->ctx != ctx);
 244         }
 245 
 246         efs->func(event, cpuctx, ctx, efs->data);
 247 unlock:
 248         perf_ctx_unlock(cpuctx, task_ctx);
 249 
 250         return ret;
 251 }
 252 
 253 static void event_function_call(struct perf_event *event, event_f func, void *data)
 254 {
 255         struct perf_event_context *ctx = event->ctx;
 256         struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
 257         struct event_function_struct efs = {
 258                 .event = event,
 259                 .func = func,
 260                 .data = data,
 261         };
 262 
 263         if (!event->parent) {
 264                 /*
 265                  * If this is a !child event, we must hold ctx::mutex to
 266                  * stabilize the the event->ctx relation. See
 267                  * perf_event_ctx_lock().
 268                  */
 269                 lockdep_assert_held(&ctx->mutex);
 270         }
 271 
 272         if (!task) {
 273                 cpu_function_call(event->cpu, event_function, &efs);
 274                 return;
 275         }
 276 
 277         if (task == TASK_TOMBSTONE)
 278                 return;
 279 
 280 again:
 281         if (!task_function_call(task, event_function, &efs))
 282                 return;
 283 
 284         raw_spin_lock_irq(&ctx->lock);
 285         /*
 286          * Reload the task pointer, it might have been changed by
 287          * a concurrent perf_event_context_sched_out().
 288          */
 289         task = ctx->task;
 290         if (task == TASK_TOMBSTONE) {
 291                 raw_spin_unlock_irq(&ctx->lock);
 292                 return;
 293         }
 294         if (ctx->is_active) {
 295                 raw_spin_unlock_irq(&ctx->lock);
 296                 goto again;
 297         }
 298         func(event, NULL, ctx, data);
 299         raw_spin_unlock_irq(&ctx->lock);
 300 }
 301 
 302 /*
 303  * Similar to event_function_call() + event_function(), but hard assumes IRQs
 304  * are already disabled and we're on the right CPU.
 305  */
 306 static void event_function_local(struct perf_event *event, event_f func, void *data)
 307 {
 308         struct perf_event_context *ctx = event->ctx;
 309         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
 310         struct task_struct *task = READ_ONCE(ctx->task);
 311         struct perf_event_context *task_ctx = NULL;
 312 
 313         lockdep_assert_irqs_disabled();
 314 
 315         if (task) {
 316                 if (task == TASK_TOMBSTONE)
 317                         return;
 318 
 319                 task_ctx = ctx;
 320         }
 321 
 322         perf_ctx_lock(cpuctx, task_ctx);
 323 
 324         task = ctx->task;
 325         if (task == TASK_TOMBSTONE)
 326                 goto unlock;
 327 
 328         if (task) {
 329                 /*
 330                  * We must be either inactive or active and the right task,
 331                  * otherwise we're screwed, since we cannot IPI to somewhere
 332                  * else.
 333                  */
 334                 if (ctx->is_active) {
 335                         if (WARN_ON_ONCE(task != current))
 336                                 goto unlock;
 337 
 338                         if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
 339                                 goto unlock;
 340                 }
 341         } else {
 342                 WARN_ON_ONCE(&cpuctx->ctx != ctx);
 343         }
 344 
 345         func(event, cpuctx, ctx, data);
 346 unlock:
 347         perf_ctx_unlock(cpuctx, task_ctx);
 348 }
 349 
 350 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
 351                        PERF_FLAG_FD_OUTPUT  |\
 352                        PERF_FLAG_PID_CGROUP |\
 353                        PERF_FLAG_FD_CLOEXEC)
 354 
 355 /*
 356  * branch priv levels that need permission checks
 357  */
 358 #define PERF_SAMPLE_BRANCH_PERM_PLM \
 359         (PERF_SAMPLE_BRANCH_KERNEL |\
 360          PERF_SAMPLE_BRANCH_HV)
 361 
 362 enum event_type_t {
 363         EVENT_FLEXIBLE = 0x1,
 364         EVENT_PINNED = 0x2,
 365         EVENT_TIME = 0x4,
 366         /* see ctx_resched() for details */
 367         EVENT_CPU = 0x8,
 368         EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
 369 };
 370 
 371 /*
 372  * perf_sched_events : >0 events exist
 373  * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
 374  */
 375 
 376 static void perf_sched_delayed(struct work_struct *work);
 377 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
 378 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
 379 static DEFINE_MUTEX(perf_sched_mutex);
 380 static atomic_t perf_sched_count;
 381 
 382 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
 383 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
 384 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
 385 
 386 static atomic_t nr_mmap_events __read_mostly;
 387 static atomic_t nr_comm_events __read_mostly;
 388 static atomic_t nr_namespaces_events __read_mostly;
 389 static atomic_t nr_task_events __read_mostly;
 390 static atomic_t nr_freq_events __read_mostly;
 391 static atomic_t nr_switch_events __read_mostly;
 392 static atomic_t nr_ksymbol_events __read_mostly;
 393 static atomic_t nr_bpf_events __read_mostly;
 394 
 395 static LIST_HEAD(pmus);
 396 static DEFINE_MUTEX(pmus_lock);
 397 static struct srcu_struct pmus_srcu;
 398 static cpumask_var_t perf_online_mask;
 399 
 400 /*
 401  * perf event paranoia level:
 402  *  -1 - not paranoid at all
 403  *   0 - disallow raw tracepoint access for unpriv
 404  *   1 - disallow cpu events for unpriv
 405  *   2 - disallow kernel profiling for unpriv
 406  */
 407 int sysctl_perf_event_paranoid __read_mostly = 2;
 408 
 409 /* Minimum for 512 kiB + 1 user control page */
 410 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
 411 
 412 /*
 413  * max perf event sample rate
 414  */
 415 #define DEFAULT_MAX_SAMPLE_RATE         100000
 416 #define DEFAULT_SAMPLE_PERIOD_NS        (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
 417 #define DEFAULT_CPU_TIME_MAX_PERCENT    25
 418 
 419 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
 420 
 421 static int max_samples_per_tick __read_mostly   = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
 422 static int perf_sample_period_ns __read_mostly  = DEFAULT_SAMPLE_PERIOD_NS;
 423 
 424 static int perf_sample_allowed_ns __read_mostly =
 425         DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
 426 
 427 static void update_perf_cpu_limits(void)
 428 {
 429         u64 tmp = perf_sample_period_ns;
 430 
 431         tmp *= sysctl_perf_cpu_time_max_percent;
 432         tmp = div_u64(tmp, 100);
 433         if (!tmp)
 434                 tmp = 1;
 435 
 436         WRITE_ONCE(perf_sample_allowed_ns, tmp);
 437 }
 438 
 439 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
 440 
 441 int perf_proc_update_handler(struct ctl_table *table, int write,
 442                 void __user *buffer, size_t *lenp,
 443                 loff_t *ppos)
 444 {
 445         int ret;
 446         int perf_cpu = sysctl_perf_cpu_time_max_percent;
 447         /*
 448          * If throttling is disabled don't allow the write:
 449          */
 450         if (write && (perf_cpu == 100 || perf_cpu == 0))
 451                 return -EINVAL;
 452 
 453         ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 454         if (ret || !write)
 455                 return ret;
 456 
 457         max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
 458         perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
 459         update_perf_cpu_limits();
 460 
 461         return 0;
 462 }
 463 
 464 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
 465 
 466 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
 467                                 void __user *buffer, size_t *lenp,
 468                                 loff_t *ppos)
 469 {
 470         int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 471 
 472         if (ret || !write)
 473                 return ret;
 474 
 475         if (sysctl_perf_cpu_time_max_percent == 100 ||
 476             sysctl_perf_cpu_time_max_percent == 0) {
 477                 printk(KERN_WARNING
 478                        "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
 479                 WRITE_ONCE(perf_sample_allowed_ns, 0);
 480         } else {
 481                 update_perf_cpu_limits();
 482         }
 483 
 484         return 0;
 485 }
 486 
 487 /*
 488  * perf samples are done in some very critical code paths (NMIs).
 489  * If they take too much CPU time, the system can lock up and not
 490  * get any real work done.  This will drop the sample rate when
 491  * we detect that events are taking too long.
 492  */
 493 #define NR_ACCUMULATED_SAMPLES 128
 494 static DEFINE_PER_CPU(u64, running_sample_length);
 495 
 496 static u64 __report_avg;
 497 static u64 __report_allowed;
 498 
 499 static void perf_duration_warn(struct irq_work *w)
 500 {
 501         printk_ratelimited(KERN_INFO
 502                 "perf: interrupt took too long (%lld > %lld), lowering "
 503                 "kernel.perf_event_max_sample_rate to %d\n",
 504                 __report_avg, __report_allowed,
 505                 sysctl_perf_event_sample_rate);
 506 }
 507 
 508 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
 509 
 510 void perf_sample_event_took(u64 sample_len_ns)
 511 {
 512         u64 max_len = READ_ONCE(perf_sample_allowed_ns);
 513         u64 running_len;
 514         u64 avg_len;
 515         u32 max;
 516 
 517         if (max_len == 0)
 518                 return;
 519 
 520         /* Decay the counter by 1 average sample. */
 521         running_len = __this_cpu_read(running_sample_length);
 522         running_len -= running_len/NR_ACCUMULATED_SAMPLES;
 523         running_len += sample_len_ns;
 524         __this_cpu_write(running_sample_length, running_len);
 525 
 526         /*
 527          * Note: this will be biased artifically low until we have
 528          * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
 529          * from having to maintain a count.
 530          */
 531         avg_len = running_len/NR_ACCUMULATED_SAMPLES;
 532         if (avg_len <= max_len)
 533                 return;
 534 
 535         __report_avg = avg_len;
 536         __report_allowed = max_len;
 537 
 538         /*
 539          * Compute a throttle threshold 25% below the current duration.
 540          */
 541         avg_len += avg_len / 4;
 542         max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
 543         if (avg_len < max)
 544                 max /= (u32)avg_len;
 545         else
 546                 max = 1;
 547 
 548         WRITE_ONCE(perf_sample_allowed_ns, avg_len);
 549         WRITE_ONCE(max_samples_per_tick, max);
 550 
 551         sysctl_perf_event_sample_rate = max * HZ;
 552         perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
 553 
 554         if (!irq_work_queue(&perf_duration_work)) {
 555                 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
 556                              "kernel.perf_event_max_sample_rate to %d\n",
 557                              __report_avg, __report_allowed,
 558                              sysctl_perf_event_sample_rate);
 559         }
 560 }
 561 
 562 static atomic64_t perf_event_id;
 563 
 564 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
 565                               enum event_type_t event_type);
 566 
 567 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
 568                              enum event_type_t event_type,
 569                              struct task_struct *task);
 570 
 571 static void update_context_time(struct perf_event_context *ctx);
 572 static u64 perf_event_time(struct perf_event *event);
 573 
 574 void __weak perf_event_print_debug(void)        { }
 575 
 576 extern __weak const char *perf_pmu_name(void)
 577 {
 578         return "pmu";
 579 }
 580 
 581 static inline u64 perf_clock(void)
 582 {
 583         return local_clock();
 584 }
 585 
 586 static inline u64 perf_event_clock(struct perf_event *event)
 587 {
 588         return event->clock();
 589 }
 590 
 591 /*
 592  * State based event timekeeping...
 593  *
 594  * The basic idea is to use event->state to determine which (if any) time
 595  * fields to increment with the current delta. This means we only need to
 596  * update timestamps when we change state or when they are explicitly requested
 597  * (read).
 598  *
 599  * Event groups make things a little more complicated, but not terribly so. The
 600  * rules for a group are that if the group leader is OFF the entire group is
 601  * OFF, irrespecive of what the group member states are. This results in
 602  * __perf_effective_state().
 603  *
 604  * A futher ramification is that when a group leader flips between OFF and
 605  * !OFF, we need to update all group member times.
 606  *
 607  *
 608  * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
 609  * need to make sure the relevant context time is updated before we try and
 610  * update our timestamps.
 611  */
 612 
 613 static __always_inline enum perf_event_state
 614 __perf_effective_state(struct perf_event *event)
 615 {
 616         struct perf_event *leader = event->group_leader;
 617 
 618         if (leader->state <= PERF_EVENT_STATE_OFF)
 619                 return leader->state;
 620 
 621         return event->state;
 622 }
 623 
 624 static __always_inline void
 625 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
 626 {
 627         enum perf_event_state state = __perf_effective_state(event);
 628         u64 delta = now - event->tstamp;
 629 
 630         *enabled = event->total_time_enabled;
 631         if (state >= PERF_EVENT_STATE_INACTIVE)
 632                 *enabled += delta;
 633 
 634         *running = event->total_time_running;
 635         if (state >= PERF_EVENT_STATE_ACTIVE)
 636                 *running += delta;
 637 }
 638 
 639 static void perf_event_update_time(struct perf_event *event)
 640 {
 641         u64 now = perf_event_time(event);
 642 
 643         __perf_update_times(event, now, &event->total_time_enabled,
 644                                         &event->total_time_running);
 645         event->tstamp = now;
 646 }
 647 
 648 static void perf_event_update_sibling_time(struct perf_event *leader)
 649 {
 650         struct perf_event *sibling;
 651 
 652         for_each_sibling_event(sibling, leader)
 653                 perf_event_update_time(sibling);
 654 }
 655 
 656 static void
 657 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
 658 {
 659         if (event->state == state)
 660                 return;
 661 
 662         perf_event_update_time(event);
 663         /*
 664          * If a group leader gets enabled/disabled all its siblings
 665          * are affected too.
 666          */
 667         if ((event->state < 0) ^ (state < 0))
 668                 perf_event_update_sibling_time(event);
 669 
 670         WRITE_ONCE(event->state, state);
 671 }
 672 
 673 #ifdef CONFIG_CGROUP_PERF
 674 
 675 static inline bool
 676 perf_cgroup_match(struct perf_event *event)
 677 {
 678         struct perf_event_context *ctx = event->ctx;
 679         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
 680 
 681         /* @event doesn't care about cgroup */
 682         if (!event->cgrp)
 683                 return true;
 684 
 685         /* wants specific cgroup scope but @cpuctx isn't associated with any */
 686         if (!cpuctx->cgrp)
 687                 return false;
 688 
 689         /*
 690          * Cgroup scoping is recursive.  An event enabled for a cgroup is
 691          * also enabled for all its descendant cgroups.  If @cpuctx's
 692          * cgroup is a descendant of @event's (the test covers identity
 693          * case), it's a match.
 694          */
 695         return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
 696                                     event->cgrp->css.cgroup);
 697 }
 698 
 699 static inline void perf_detach_cgroup(struct perf_event *event)
 700 {
 701         css_put(&event->cgrp->css);
 702         event->cgrp = NULL;
 703 }
 704 
 705 static inline int is_cgroup_event(struct perf_event *event)
 706 {
 707         return event->cgrp != NULL;
 708 }
 709 
 710 static inline u64 perf_cgroup_event_time(struct perf_event *event)
 711 {
 712         struct perf_cgroup_info *t;
 713 
 714         t = per_cpu_ptr(event->cgrp->info, event->cpu);
 715         return t->time;
 716 }
 717 
 718 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
 719 {
 720         struct perf_cgroup_info *info;
 721         u64 now;
 722 
 723         now = perf_clock();
 724 
 725         info = this_cpu_ptr(cgrp->info);
 726 
 727         info->time += now - info->timestamp;
 728         info->timestamp = now;
 729 }
 730 
 731 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
 732 {
 733         struct perf_cgroup *cgrp = cpuctx->cgrp;
 734         struct cgroup_subsys_state *css;
 735 
 736         if (cgrp) {
 737                 for (css = &cgrp->css; css; css = css->parent) {
 738                         cgrp = container_of(css, struct perf_cgroup, css);
 739                         __update_cgrp_time(cgrp);
 740                 }
 741         }
 742 }
 743 
 744 static inline void update_cgrp_time_from_event(struct perf_event *event)
 745 {
 746         struct perf_cgroup *cgrp;
 747 
 748         /*
 749          * ensure we access cgroup data only when needed and
 750          * when we know the cgroup is pinned (css_get)
 751          */
 752         if (!is_cgroup_event(event))
 753                 return;
 754 
 755         cgrp = perf_cgroup_from_task(current, event->ctx);
 756         /*
 757          * Do not update time when cgroup is not active
 758          */
 759         if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
 760                 __update_cgrp_time(event->cgrp);
 761 }
 762 
 763 static inline void
 764 perf_cgroup_set_timestamp(struct task_struct *task,
 765                           struct perf_event_context *ctx)
 766 {
 767         struct perf_cgroup *cgrp;
 768         struct perf_cgroup_info *info;
 769         struct cgroup_subsys_state *css;
 770 
 771         /*
 772          * ctx->lock held by caller
 773          * ensure we do not access cgroup data
 774          * unless we have the cgroup pinned (css_get)
 775          */
 776         if (!task || !ctx->nr_cgroups)
 777                 return;
 778 
 779         cgrp = perf_cgroup_from_task(task, ctx);
 780 
 781         for (css = &cgrp->css; css; css = css->parent) {
 782                 cgrp = container_of(css, struct perf_cgroup, css);
 783                 info = this_cpu_ptr(cgrp->info);
 784                 info->timestamp = ctx->timestamp;
 785         }
 786 }
 787 
 788 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
 789 
 790 #define PERF_CGROUP_SWOUT       0x1 /* cgroup switch out every event */
 791 #define PERF_CGROUP_SWIN        0x2 /* cgroup switch in events based on task */
 792 
 793 /*
 794  * reschedule events based on the cgroup constraint of task.
 795  *
 796  * mode SWOUT : schedule out everything
 797  * mode SWIN : schedule in based on cgroup for next
 798  */
 799 static void perf_cgroup_switch(struct task_struct *task, int mode)
 800 {
 801         struct perf_cpu_context *cpuctx;
 802         struct list_head *list;
 803         unsigned long flags;
 804 
 805         /*
 806          * Disable interrupts and preemption to avoid this CPU's
 807          * cgrp_cpuctx_entry to change under us.
 808          */
 809         local_irq_save(flags);
 810 
 811         list = this_cpu_ptr(&cgrp_cpuctx_list);
 812         list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
 813                 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
 814 
 815                 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
 816                 perf_pmu_disable(cpuctx->ctx.pmu);
 817 
 818                 if (mode & PERF_CGROUP_SWOUT) {
 819                         cpu_ctx_sched_out(cpuctx, EVENT_ALL);
 820                         /*
 821                          * must not be done before ctxswout due
 822                          * to event_filter_match() in event_sched_out()
 823                          */
 824                         cpuctx->cgrp = NULL;
 825                 }
 826 
 827                 if (mode & PERF_CGROUP_SWIN) {
 828                         WARN_ON_ONCE(cpuctx->cgrp);
 829                         /*
 830                          * set cgrp before ctxsw in to allow
 831                          * event_filter_match() to not have to pass
 832                          * task around
 833                          * we pass the cpuctx->ctx to perf_cgroup_from_task()
 834                          * because cgorup events are only per-cpu
 835                          */
 836                         cpuctx->cgrp = perf_cgroup_from_task(task,
 837                                                              &cpuctx->ctx);
 838                         cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
 839                 }
 840                 perf_pmu_enable(cpuctx->ctx.pmu);
 841                 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 842         }
 843 
 844         local_irq_restore(flags);
 845 }
 846 
 847 static inline void perf_cgroup_sched_out(struct task_struct *task,
 848                                          struct task_struct *next)
 849 {
 850         struct perf_cgroup *cgrp1;
 851         struct perf_cgroup *cgrp2 = NULL;
 852 
 853         rcu_read_lock();
 854         /*
 855          * we come here when we know perf_cgroup_events > 0
 856          * we do not need to pass the ctx here because we know
 857          * we are holding the rcu lock
 858          */
 859         cgrp1 = perf_cgroup_from_task(task, NULL);
 860         cgrp2 = perf_cgroup_from_task(next, NULL);
 861 
 862         /*
 863          * only schedule out current cgroup events if we know
 864          * that we are switching to a different cgroup. Otherwise,
 865          * do no touch the cgroup events.
 866          */
 867         if (cgrp1 != cgrp2)
 868                 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
 869 
 870         rcu_read_unlock();
 871 }
 872 
 873 static inline void perf_cgroup_sched_in(struct task_struct *prev,
 874                                         struct task_struct *task)
 875 {
 876         struct perf_cgroup *cgrp1;
 877         struct perf_cgroup *cgrp2 = NULL;
 878 
 879         rcu_read_lock();
 880         /*
 881          * we come here when we know perf_cgroup_events > 0
 882          * we do not need to pass the ctx here because we know
 883          * we are holding the rcu lock
 884          */
 885         cgrp1 = perf_cgroup_from_task(task, NULL);
 886         cgrp2 = perf_cgroup_from_task(prev, NULL);
 887 
 888         /*
 889          * only need to schedule in cgroup events if we are changing
 890          * cgroup during ctxsw. Cgroup events were not scheduled
 891          * out of ctxsw out if that was not the case.
 892          */
 893         if (cgrp1 != cgrp2)
 894                 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
 895 
 896         rcu_read_unlock();
 897 }
 898 
 899 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
 900                                       struct perf_event_attr *attr,
 901                                       struct perf_event *group_leader)
 902 {
 903         struct perf_cgroup *cgrp;
 904         struct cgroup_subsys_state *css;
 905         struct fd f = fdget(fd);
 906         int ret = 0;
 907 
 908         if (!f.file)
 909                 return -EBADF;
 910 
 911         css = css_tryget_online_from_dir(f.file->f_path.dentry,
 912                                          &perf_event_cgrp_subsys);
 913         if (IS_ERR(css)) {
 914                 ret = PTR_ERR(css);
 915                 goto out;
 916         }
 917 
 918         cgrp = container_of(css, struct perf_cgroup, css);
 919         event->cgrp = cgrp;
 920 
 921         /*
 922          * all events in a group must monitor
 923          * the same cgroup because a task belongs
 924          * to only one perf cgroup at a time
 925          */
 926         if (group_leader && group_leader->cgrp != cgrp) {
 927                 perf_detach_cgroup(event);
 928                 ret = -EINVAL;
 929         }
 930 out:
 931         fdput(f);
 932         return ret;
 933 }
 934 
 935 static inline void
 936 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
 937 {
 938         struct perf_cgroup_info *t;
 939         t = per_cpu_ptr(event->cgrp->info, event->cpu);
 940         event->shadow_ctx_time = now - t->timestamp;
 941 }
 942 
 943 /*
 944  * Update cpuctx->cgrp so that it is set when first cgroup event is added and
 945  * cleared when last cgroup event is removed.
 946  */
 947 static inline void
 948 list_update_cgroup_event(struct perf_event *event,
 949                          struct perf_event_context *ctx, bool add)
 950 {
 951         struct perf_cpu_context *cpuctx;
 952         struct list_head *cpuctx_entry;
 953 
 954         if (!is_cgroup_event(event))
 955                 return;
 956 
 957         /*
 958          * Because cgroup events are always per-cpu events,
 959          * this will always be called from the right CPU.
 960          */
 961         cpuctx = __get_cpu_context(ctx);
 962 
 963         /*
 964          * Since setting cpuctx->cgrp is conditional on the current @cgrp
 965          * matching the event's cgroup, we must do this for every new event,
 966          * because if the first would mismatch, the second would not try again
 967          * and we would leave cpuctx->cgrp unset.
 968          */
 969         if (add && !cpuctx->cgrp) {
 970                 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
 971 
 972                 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
 973                         cpuctx->cgrp = cgrp;
 974         }
 975 
 976         if (add && ctx->nr_cgroups++)
 977                 return;
 978         else if (!add && --ctx->nr_cgroups)
 979                 return;
 980 
 981         /* no cgroup running */
 982         if (!add)
 983                 cpuctx->cgrp = NULL;
 984 
 985         cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
 986         if (add)
 987                 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
 988         else
 989                 list_del(cpuctx_entry);
 990 }
 991 
 992 #else /* !CONFIG_CGROUP_PERF */
 993 
 994 static inline bool
 995 perf_cgroup_match(struct perf_event *event)
 996 {
 997         return true;
 998 }
 999 
1000 static inline void perf_detach_cgroup(struct perf_event *event)
1001 {}
1002 
1003 static inline int is_cgroup_event(struct perf_event *event)
1004 {
1005         return 0;
1006 }
1007 
1008 static inline void update_cgrp_time_from_event(struct perf_event *event)
1009 {
1010 }
1011 
1012 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1013 {
1014 }
1015 
1016 static inline void perf_cgroup_sched_out(struct task_struct *task,
1017                                          struct task_struct *next)
1018 {
1019 }
1020 
1021 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1022                                         struct task_struct *task)
1023 {
1024 }
1025 
1026 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1027                                       struct perf_event_attr *attr,
1028                                       struct perf_event *group_leader)
1029 {
1030         return -EINVAL;
1031 }
1032 
1033 static inline void
1034 perf_cgroup_set_timestamp(struct task_struct *task,
1035                           struct perf_event_context *ctx)
1036 {
1037 }
1038 
1039 static inline void
1040 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1041 {
1042 }
1043 
1044 static inline void
1045 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1046 {
1047 }
1048 
1049 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1050 {
1051         return 0;
1052 }
1053 
1054 static inline void
1055 list_update_cgroup_event(struct perf_event *event,
1056                          struct perf_event_context *ctx, bool add)
1057 {
1058 }
1059 
1060 #endif
1061 
1062 /*
1063  * set default to be dependent on timer tick just
1064  * like original code
1065  */
1066 #define PERF_CPU_HRTIMER (1000 / HZ)
1067 /*
1068  * function must be called with interrupts disabled
1069  */
1070 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1071 {
1072         struct perf_cpu_context *cpuctx;
1073         bool rotations;
1074 
1075         lockdep_assert_irqs_disabled();
1076 
1077         cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1078         rotations = perf_rotate_context(cpuctx);
1079 
1080         raw_spin_lock(&cpuctx->hrtimer_lock);
1081         if (rotations)
1082                 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1083         else
1084                 cpuctx->hrtimer_active = 0;
1085         raw_spin_unlock(&cpuctx->hrtimer_lock);
1086 
1087         return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1088 }
1089 
1090 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1091 {
1092         struct hrtimer *timer = &cpuctx->hrtimer;
1093         struct pmu *pmu = cpuctx->ctx.pmu;
1094         u64 interval;
1095 
1096         /* no multiplexing needed for SW PMU */
1097         if (pmu->task_ctx_nr == perf_sw_context)
1098                 return;
1099 
1100         /*
1101          * check default is sane, if not set then force to
1102          * default interval (1/tick)
1103          */
1104         interval = pmu->hrtimer_interval_ms;
1105         if (interval < 1)
1106                 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1107 
1108         cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1109 
1110         raw_spin_lock_init(&cpuctx->hrtimer_lock);
1111         hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1112         timer->function = perf_mux_hrtimer_handler;
1113 }
1114 
1115 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1116 {
1117         struct hrtimer *timer = &cpuctx->hrtimer;
1118         struct pmu *pmu = cpuctx->ctx.pmu;
1119         unsigned long flags;
1120 
1121         /* not for SW PMU */
1122         if (pmu->task_ctx_nr == perf_sw_context)
1123                 return 0;
1124 
1125         raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1126         if (!cpuctx->hrtimer_active) {
1127                 cpuctx->hrtimer_active = 1;
1128                 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1129                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1130         }
1131         raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1132 
1133         return 0;
1134 }
1135 
1136 void perf_pmu_disable(struct pmu *pmu)
1137 {
1138         int *count = this_cpu_ptr(pmu->pmu_disable_count);
1139         if (!(*count)++)
1140                 pmu->pmu_disable(pmu);
1141 }
1142 
1143 void perf_pmu_enable(struct pmu *pmu)
1144 {
1145         int *count = this_cpu_ptr(pmu->pmu_disable_count);
1146         if (!--(*count))
1147                 pmu->pmu_enable(pmu);
1148 }
1149 
1150 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1151 
1152 /*
1153  * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1154  * perf_event_task_tick() are fully serialized because they're strictly cpu
1155  * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1156  * disabled, while perf_event_task_tick is called from IRQ context.
1157  */
1158 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1159 {
1160         struct list_head *head = this_cpu_ptr(&active_ctx_list);
1161 
1162         lockdep_assert_irqs_disabled();
1163 
1164         WARN_ON(!list_empty(&ctx->active_ctx_list));
1165 
1166         list_add(&ctx->active_ctx_list, head);
1167 }
1168 
1169 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1170 {
1171         lockdep_assert_irqs_disabled();
1172 
1173         WARN_ON(list_empty(&ctx->active_ctx_list));
1174 
1175         list_del_init(&ctx->active_ctx_list);
1176 }
1177 
1178 static void get_ctx(struct perf_event_context *ctx)
1179 {
1180         refcount_inc(&ctx->refcount);
1181 }
1182 
1183 static void free_ctx(struct rcu_head *head)
1184 {
1185         struct perf_event_context *ctx;
1186 
1187         ctx = container_of(head, struct perf_event_context, rcu_head);
1188         kfree(ctx->task_ctx_data);
1189         kfree(ctx);
1190 }
1191 
1192 static void put_ctx(struct perf_event_context *ctx)
1193 {
1194         if (refcount_dec_and_test(&ctx->refcount)) {
1195                 if (ctx->parent_ctx)
1196                         put_ctx(ctx->parent_ctx);
1197                 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1198                         put_task_struct(ctx->task);
1199                 call_rcu(&ctx->rcu_head, free_ctx);
1200         }
1201 }
1202 
1203 /*
1204  * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1205  * perf_pmu_migrate_context() we need some magic.
1206  *
1207  * Those places that change perf_event::ctx will hold both
1208  * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1209  *
1210  * Lock ordering is by mutex address. There are two other sites where
1211  * perf_event_context::mutex nests and those are:
1212  *
1213  *  - perf_event_exit_task_context()    [ child , 0 ]
1214  *      perf_event_exit_event()
1215  *        put_event()                   [ parent, 1 ]
1216  *
1217  *  - perf_event_init_context()         [ parent, 0 ]
1218  *      inherit_task_group()
1219  *        inherit_group()
1220  *          inherit_event()
1221  *            perf_event_alloc()
1222  *              perf_init_event()
1223  *                perf_try_init_event() [ child , 1 ]
1224  *
1225  * While it appears there is an obvious deadlock here -- the parent and child
1226  * nesting levels are inverted between the two. This is in fact safe because
1227  * life-time rules separate them. That is an exiting task cannot fork, and a
1228  * spawning task cannot (yet) exit.
1229  *
1230  * But remember that that these are parent<->child context relations, and
1231  * migration does not affect children, therefore these two orderings should not
1232  * interact.
1233  *
1234  * The change in perf_event::ctx does not affect children (as claimed above)
1235  * because the sys_perf_event_open() case will install a new event and break
1236  * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1237  * concerned with cpuctx and that doesn't have children.
1238  *
1239  * The places that change perf_event::ctx will issue:
1240  *
1241  *   perf_remove_from_context();
1242  *   synchronize_rcu();
1243  *   perf_install_in_context();
1244  *
1245  * to affect the change. The remove_from_context() + synchronize_rcu() should
1246  * quiesce the event, after which we can install it in the new location. This
1247  * means that only external vectors (perf_fops, prctl) can perturb the event
1248  * while in transit. Therefore all such accessors should also acquire
1249  * perf_event_context::mutex to serialize against this.
1250  *
1251  * However; because event->ctx can change while we're waiting to acquire
1252  * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1253  * function.
1254  *
1255  * Lock order:
1256  *    cred_guard_mutex
1257  *      task_struct::perf_event_mutex
1258  *        perf_event_context::mutex
1259  *          perf_event::child_mutex;
1260  *            perf_event_context::lock
1261  *          perf_event::mmap_mutex
1262  *          mmap_sem
1263  *            perf_addr_filters_head::lock
1264  *
1265  *    cpu_hotplug_lock
1266  *      pmus_lock
1267  *        cpuctx->mutex / perf_event_context::mutex
1268  */
1269 static struct perf_event_context *
1270 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1271 {
1272         struct perf_event_context *ctx;
1273 
1274 again:
1275         rcu_read_lock();
1276         ctx = READ_ONCE(event->ctx);
1277         if (!refcount_inc_not_zero(&ctx->refcount)) {
1278                 rcu_read_unlock();
1279                 goto again;
1280         }
1281         rcu_read_unlock();
1282 
1283         mutex_lock_nested(&ctx->mutex, nesting);
1284         if (event->ctx != ctx) {
1285                 mutex_unlock(&ctx->mutex);
1286                 put_ctx(ctx);
1287                 goto again;
1288         }
1289 
1290         return ctx;
1291 }
1292 
1293 static inline struct perf_event_context *
1294 perf_event_ctx_lock(struct perf_event *event)
1295 {
1296         return perf_event_ctx_lock_nested(event, 0);
1297 }
1298 
1299 static void perf_event_ctx_unlock(struct perf_event *event,
1300                                   struct perf_event_context *ctx)
1301 {
1302         mutex_unlock(&ctx->mutex);
1303         put_ctx(ctx);
1304 }
1305 
1306 /*
1307  * This must be done under the ctx->lock, such as to serialize against
1308  * context_equiv(), therefore we cannot call put_ctx() since that might end up
1309  * calling scheduler related locks and ctx->lock nests inside those.
1310  */
1311 static __must_check struct perf_event_context *
1312 unclone_ctx(struct perf_event_context *ctx)
1313 {
1314         struct perf_event_context *parent_ctx = ctx->parent_ctx;
1315 
1316         lockdep_assert_held(&ctx->lock);
1317 
1318         if (parent_ctx)
1319                 ctx->parent_ctx = NULL;
1320         ctx->generation++;
1321 
1322         return parent_ctx;
1323 }
1324 
1325 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1326                                 enum pid_type type)
1327 {
1328         u32 nr;
1329         /*
1330          * only top level events have the pid namespace they were created in
1331          */
1332         if (event->parent)
1333                 event = event->parent;
1334 
1335         nr = __task_pid_nr_ns(p, type, event->ns);
1336         /* avoid -1 if it is idle thread or runs in another ns */
1337         if (!nr && !pid_alive(p))
1338                 nr = -1;
1339         return nr;
1340 }
1341 
1342 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1343 {
1344         return perf_event_pid_type(event, p, PIDTYPE_TGID);
1345 }
1346 
1347 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1348 {
1349         return perf_event_pid_type(event, p, PIDTYPE_PID);
1350 }
1351 
1352 /*
1353  * If we inherit events we want to return the parent event id
1354  * to userspace.
1355  */
1356 static u64 primary_event_id(struct perf_event *event)
1357 {
1358         u64 id = event->id;
1359 
1360         if (event->parent)
1361                 id = event->parent->id;
1362 
1363         return id;
1364 }
1365 
1366 /*
1367  * Get the perf_event_context for a task and lock it.
1368  *
1369  * This has to cope with with the fact that until it is locked,
1370  * the context could get moved to another task.
1371  */
1372 static struct perf_event_context *
1373 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1374 {
1375         struct perf_event_context *ctx;
1376 
1377 retry:
1378         /*
1379          * One of the few rules of preemptible RCU is that one cannot do
1380          * rcu_read_unlock() while holding a scheduler (or nested) lock when
1381          * part of the read side critical section was irqs-enabled -- see
1382          * rcu_read_unlock_special().
1383          *
1384          * Since ctx->lock nests under rq->lock we must ensure the entire read
1385          * side critical section has interrupts disabled.
1386          */
1387         local_irq_save(*flags);
1388         rcu_read_lock();
1389         ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1390         if (ctx) {
1391                 /*
1392                  * If this context is a clone of another, it might
1393                  * get swapped for another underneath us by
1394                  * perf_event_task_sched_out, though the
1395                  * rcu_read_lock() protects us from any context
1396                  * getting freed.  Lock the context and check if it
1397                  * got swapped before we could get the lock, and retry
1398                  * if so.  If we locked the right context, then it
1399                  * can't get swapped on us any more.
1400                  */
1401                 raw_spin_lock(&ctx->lock);
1402                 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1403                         raw_spin_unlock(&ctx->lock);
1404                         rcu_read_unlock();
1405                         local_irq_restore(*flags);
1406                         goto retry;
1407                 }
1408 
1409                 if (ctx->task == TASK_TOMBSTONE ||
1410                     !refcount_inc_not_zero(&ctx->refcount)) {
1411                         raw_spin_unlock(&ctx->lock);
1412                         ctx = NULL;
1413                 } else {
1414                         WARN_ON_ONCE(ctx->task != task);
1415                 }
1416         }
1417         rcu_read_unlock();
1418         if (!ctx)
1419                 local_irq_restore(*flags);
1420         return ctx;
1421 }
1422 
1423 /*
1424  * Get the context for a task and increment its pin_count so it
1425  * can't get swapped to another task.  This also increments its
1426  * reference count so that the context can't get freed.
1427  */
1428 static struct perf_event_context *
1429 perf_pin_task_context(struct task_struct *task, int ctxn)
1430 {
1431         struct perf_event_context *ctx;
1432         unsigned long flags;
1433 
1434         ctx = perf_lock_task_context(task, ctxn, &flags);
1435         if (ctx) {
1436                 ++ctx->pin_count;
1437                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1438         }
1439         return ctx;
1440 }
1441 
1442 static void perf_unpin_context(struct perf_event_context *ctx)
1443 {
1444         unsigned long flags;
1445 
1446         raw_spin_lock_irqsave(&ctx->lock, flags);
1447         --ctx->pin_count;
1448         raw_spin_unlock_irqrestore(&ctx->lock, flags);
1449 }
1450 
1451 /*
1452  * Update the record of the current time in a context.
1453  */
1454 static void update_context_time(struct perf_event_context *ctx)
1455 {
1456         u64 now = perf_clock();
1457 
1458         ctx->time += now - ctx->timestamp;
1459         ctx->timestamp = now;
1460 }
1461 
1462 static u64 perf_event_time(struct perf_event *event)
1463 {
1464         struct perf_event_context *ctx = event->ctx;
1465 
1466         if (is_cgroup_event(event))
1467                 return perf_cgroup_event_time(event);
1468 
1469         return ctx ? ctx->time : 0;
1470 }
1471 
1472 static enum event_type_t get_event_type(struct perf_event *event)
1473 {
1474         struct perf_event_context *ctx = event->ctx;
1475         enum event_type_t event_type;
1476 
1477         lockdep_assert_held(&ctx->lock);
1478 
1479         /*
1480          * It's 'group type', really, because if our group leader is
1481          * pinned, so are we.
1482          */
1483         if (event->group_leader != event)
1484                 event = event->group_leader;
1485 
1486         event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1487         if (!ctx->task)
1488                 event_type |= EVENT_CPU;
1489 
1490         return event_type;
1491 }
1492 
1493 /*
1494  * Helper function to initialize event group nodes.
1495  */
1496 static void init_event_group(struct perf_event *event)
1497 {
1498         RB_CLEAR_NODE(&event->group_node);
1499         event->group_index = 0;
1500 }
1501 
1502 /*
1503  * Extract pinned or flexible groups from the context
1504  * based on event attrs bits.
1505  */
1506 static struct perf_event_groups *
1507 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1508 {
1509         if (event->attr.pinned)
1510                 return &ctx->pinned_groups;
1511         else
1512                 return &ctx->flexible_groups;
1513 }
1514 
1515 /*
1516  * Helper function to initializes perf_event_group trees.
1517  */
1518 static void perf_event_groups_init(struct perf_event_groups *groups)
1519 {
1520         groups->tree = RB_ROOT;
1521         groups->index = 0;
1522 }
1523 
1524 /*
1525  * Compare function for event groups;
1526  *
1527  * Implements complex key that first sorts by CPU and then by virtual index
1528  * which provides ordering when rotating groups for the same CPU.
1529  */
1530 static bool
1531 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1532 {
1533         if (left->cpu < right->cpu)
1534                 return true;
1535         if (left->cpu > right->cpu)
1536                 return false;
1537 
1538         if (left->group_index < right->group_index)
1539                 return true;
1540         if (left->group_index > right->group_index)
1541                 return false;
1542 
1543         return false;
1544 }
1545 
1546 /*
1547  * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1548  * key (see perf_event_groups_less). This places it last inside the CPU
1549  * subtree.
1550  */
1551 static void
1552 perf_event_groups_insert(struct perf_event_groups *groups,
1553                          struct perf_event *event)
1554 {
1555         struct perf_event *node_event;
1556         struct rb_node *parent;
1557         struct rb_node **node;
1558 
1559         event->group_index = ++groups->index;
1560 
1561         node = &groups->tree.rb_node;
1562         parent = *node;
1563 
1564         while (*node) {
1565                 parent = *node;
1566                 node_event = container_of(*node, struct perf_event, group_node);
1567 
1568                 if (perf_event_groups_less(event, node_event))
1569                         node = &parent->rb_left;
1570                 else
1571                         node = &parent->rb_right;
1572         }
1573 
1574         rb_link_node(&event->group_node, parent, node);
1575         rb_insert_color(&event->group_node, &groups->tree);
1576 }
1577 
1578 /*
1579  * Helper function to insert event into the pinned or flexible groups.
1580  */
1581 static void
1582 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1583 {
1584         struct perf_event_groups *groups;
1585 
1586         groups = get_event_groups(event, ctx);
1587         perf_event_groups_insert(groups, event);
1588 }
1589 
1590 /*
1591  * Delete a group from a tree.
1592  */
1593 static void
1594 perf_event_groups_delete(struct perf_event_groups *groups,
1595                          struct perf_event *event)
1596 {
1597         WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1598                      RB_EMPTY_ROOT(&groups->tree));
1599 
1600         rb_erase(&event->group_node, &groups->tree);
1601         init_event_group(event);
1602 }
1603 
1604 /*
1605  * Helper function to delete event from its groups.
1606  */
1607 static void
1608 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1609 {
1610         struct perf_event_groups *groups;
1611 
1612         groups = get_event_groups(event, ctx);
1613         perf_event_groups_delete(groups, event);
1614 }
1615 
1616 /*
1617  * Get the leftmost event in the @cpu subtree.
1618  */
1619 static struct perf_event *
1620 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1621 {
1622         struct perf_event *node_event = NULL, *match = NULL;
1623         struct rb_node *node = groups->tree.rb_node;
1624 
1625         while (node) {
1626                 node_event = container_of(node, struct perf_event, group_node);
1627 
1628                 if (cpu < node_event->cpu) {
1629                         node = node->rb_left;
1630                 } else if (cpu > node_event->cpu) {
1631                         node = node->rb_right;
1632                 } else {
1633                         match = node_event;
1634                         node = node->rb_left;
1635                 }
1636         }
1637 
1638         return match;
1639 }
1640 
1641 /*
1642  * Like rb_entry_next_safe() for the @cpu subtree.
1643  */
1644 static struct perf_event *
1645 perf_event_groups_next(struct perf_event *event)
1646 {
1647         struct perf_event *next;
1648 
1649         next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1650         if (next && next->cpu == event->cpu)
1651                 return next;
1652 
1653         return NULL;
1654 }
1655 
1656 /*
1657  * Iterate through the whole groups tree.
1658  */
1659 #define perf_event_groups_for_each(event, groups)                       \
1660         for (event = rb_entry_safe(rb_first(&((groups)->tree)),         \
1661                                 typeof(*event), group_node); event;     \
1662                 event = rb_entry_safe(rb_next(&event->group_node),      \
1663                                 typeof(*event), group_node))
1664 
1665 /*
1666  * Add an event from the lists for its context.
1667  * Must be called with ctx->mutex and ctx->lock held.
1668  */
1669 static void
1670 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1671 {
1672         lockdep_assert_held(&ctx->lock);
1673 
1674         WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1675         event->attach_state |= PERF_ATTACH_CONTEXT;
1676 
1677         event->tstamp = perf_event_time(event);
1678 
1679         /*
1680          * If we're a stand alone event or group leader, we go to the context
1681          * list, group events are kept attached to the group so that
1682          * perf_group_detach can, at all times, locate all siblings.
1683          */
1684         if (event->group_leader == event) {
1685                 event->group_caps = event->event_caps;
1686                 add_event_to_groups(event, ctx);
1687         }
1688 
1689         list_update_cgroup_event(event, ctx, true);
1690 
1691         list_add_rcu(&event->event_entry, &ctx->event_list);
1692         ctx->nr_events++;
1693         if (event->attr.inherit_stat)
1694                 ctx->nr_stat++;
1695 
1696         ctx->generation++;
1697 }
1698 
1699 /*
1700  * Initialize event state based on the perf_event_attr::disabled.
1701  */
1702 static inline void perf_event__state_init(struct perf_event *event)
1703 {
1704         event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1705                                               PERF_EVENT_STATE_INACTIVE;
1706 }
1707 
1708 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1709 {
1710         int entry = sizeof(u64); /* value */
1711         int size = 0;
1712         int nr = 1;
1713 
1714         if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1715                 size += sizeof(u64);
1716 
1717         if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1718                 size += sizeof(u64);
1719 
1720         if (event->attr.read_format & PERF_FORMAT_ID)
1721                 entry += sizeof(u64);
1722 
1723         if (event->attr.read_format & PERF_FORMAT_GROUP) {
1724                 nr += nr_siblings;
1725                 size += sizeof(u64);
1726         }
1727 
1728         size += entry * nr;
1729         event->read_size = size;
1730 }
1731 
1732 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1733 {
1734         struct perf_sample_data *data;
1735         u16 size = 0;
1736 
1737         if (sample_type & PERF_SAMPLE_IP)
1738                 size += sizeof(data->ip);
1739 
1740         if (sample_type & PERF_SAMPLE_ADDR)
1741                 size += sizeof(data->addr);
1742 
1743         if (sample_type & PERF_SAMPLE_PERIOD)
1744                 size += sizeof(data->period);
1745 
1746         if (sample_type & PERF_SAMPLE_WEIGHT)
1747                 size += sizeof(data->weight);
1748 
1749         if (sample_type & PERF_SAMPLE_READ)
1750                 size += event->read_size;
1751 
1752         if (sample_type & PERF_SAMPLE_DATA_SRC)
1753                 size += sizeof(data->data_src.val);
1754 
1755         if (sample_type & PERF_SAMPLE_TRANSACTION)
1756                 size += sizeof(data->txn);
1757 
1758         if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1759                 size += sizeof(data->phys_addr);
1760 
1761         event->header_size = size;
1762 }
1763 
1764 /*
1765  * Called at perf_event creation and when events are attached/detached from a
1766  * group.
1767  */
1768 static void perf_event__header_size(struct perf_event *event)
1769 {
1770         __perf_event_read_size(event,
1771                                event->group_leader->nr_siblings);
1772         __perf_event_header_size(event, event->attr.sample_type);
1773 }
1774 
1775 static void perf_event__id_header_size(struct perf_event *event)
1776 {
1777         struct perf_sample_data *data;
1778         u64 sample_type = event->attr.sample_type;
1779         u16 size = 0;
1780 
1781         if (sample_type & PERF_SAMPLE_TID)
1782                 size += sizeof(data->tid_entry);
1783 
1784         if (sample_type & PERF_SAMPLE_TIME)
1785                 size += sizeof(data->time);
1786 
1787         if (sample_type & PERF_SAMPLE_IDENTIFIER)
1788                 size += sizeof(data->id);
1789 
1790         if (sample_type & PERF_SAMPLE_ID)
1791                 size += sizeof(data->id);
1792 
1793         if (sample_type & PERF_SAMPLE_STREAM_ID)
1794                 size += sizeof(data->stream_id);
1795 
1796         if (sample_type & PERF_SAMPLE_CPU)
1797                 size += sizeof(data->cpu_entry);
1798 
1799         event->id_header_size = size;
1800 }
1801 
1802 static bool perf_event_validate_size(struct perf_event *event)
1803 {
1804         /*
1805          * The values computed here will be over-written when we actually
1806          * attach the event.
1807          */
1808         __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1809         __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1810         perf_event__id_header_size(event);
1811 
1812         /*
1813          * Sum the lot; should not exceed the 64k limit we have on records.
1814          * Conservative limit to allow for callchains and other variable fields.
1815          */
1816         if (event->read_size + event->header_size +
1817             event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1818                 return false;
1819 
1820         return true;
1821 }
1822 
1823 static void perf_group_attach(struct perf_event *event)
1824 {
1825         struct perf_event *group_leader = event->group_leader, *pos;
1826 
1827         lockdep_assert_held(&event->ctx->lock);
1828 
1829         /*
1830          * We can have double attach due to group movement in perf_event_open.
1831          */
1832         if (event->attach_state & PERF_ATTACH_GROUP)
1833                 return;
1834 
1835         event->attach_state |= PERF_ATTACH_GROUP;
1836 
1837         if (group_leader == event)
1838                 return;
1839 
1840         WARN_ON_ONCE(group_leader->ctx != event->ctx);
1841 
1842         group_leader->group_caps &= event->event_caps;
1843 
1844         list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1845         group_leader->nr_siblings++;
1846 
1847         perf_event__header_size(group_leader);
1848 
1849         for_each_sibling_event(pos, group_leader)
1850                 perf_event__header_size(pos);
1851 }
1852 
1853 /*
1854  * Remove an event from the lists for its context.
1855  * Must be called with ctx->mutex and ctx->lock held.
1856  */
1857 static void
1858 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1859 {
1860         WARN_ON_ONCE(event->ctx != ctx);
1861         lockdep_assert_held(&ctx->lock);
1862 
1863         /*
1864          * We can have double detach due to exit/hot-unplug + close.
1865          */
1866         if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1867                 return;
1868 
1869         event->attach_state &= ~PERF_ATTACH_CONTEXT;
1870 
1871         list_update_cgroup_event(event, ctx, false);
1872 
1873         ctx->nr_events--;
1874         if (event->attr.inherit_stat)
1875                 ctx->nr_stat--;
1876 
1877         list_del_rcu(&event->event_entry);
1878 
1879         if (event->group_leader == event)
1880                 del_event_from_groups(event, ctx);
1881 
1882         /*
1883          * If event was in error state, then keep it
1884          * that way, otherwise bogus counts will be
1885          * returned on read(). The only way to get out
1886          * of error state is by explicit re-enabling
1887          * of the event
1888          */
1889         if (event->state > PERF_EVENT_STATE_OFF)
1890                 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1891 
1892         ctx->generation++;
1893 }
1894 
1895 static int
1896 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
1897 {
1898         if (!has_aux(aux_event))
1899                 return 0;
1900 
1901         if (!event->pmu->aux_output_match)
1902                 return 0;
1903 
1904         return event->pmu->aux_output_match(aux_event);
1905 }
1906 
1907 static void put_event(struct perf_event *event);
1908 static void event_sched_out(struct perf_event *event,
1909                             struct perf_cpu_context *cpuctx,
1910                             struct perf_event_context *ctx);
1911 
1912 static void perf_put_aux_event(struct perf_event *event)
1913 {
1914         struct perf_event_context *ctx = event->ctx;
1915         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1916         struct perf_event *iter;
1917 
1918         /*
1919          * If event uses aux_event tear down the link
1920          */
1921         if (event->aux_event) {
1922                 iter = event->aux_event;
1923                 event->aux_event = NULL;
1924                 put_event(iter);
1925                 return;
1926         }
1927 
1928         /*
1929          * If the event is an aux_event, tear down all links to
1930          * it from other events.
1931          */
1932         for_each_sibling_event(iter, event->group_leader) {
1933                 if (iter->aux_event != event)
1934                         continue;
1935 
1936                 iter->aux_event = NULL;
1937                 put_event(event);
1938 
1939                 /*
1940                  * If it's ACTIVE, schedule it out and put it into ERROR
1941                  * state so that we don't try to schedule it again. Note
1942                  * that perf_event_enable() will clear the ERROR status.
1943                  */
1944                 event_sched_out(iter, cpuctx, ctx);
1945                 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
1946         }
1947 }
1948 
1949 static int perf_get_aux_event(struct perf_event *event,
1950                               struct perf_event *group_leader)
1951 {
1952         /*
1953          * Our group leader must be an aux event if we want to be
1954          * an aux_output. This way, the aux event will precede its
1955          * aux_output events in the group, and therefore will always
1956          * schedule first.
1957          */
1958         if (!group_leader)
1959                 return 0;
1960 
1961         if (!perf_aux_output_match(event, group_leader))
1962                 return 0;
1963 
1964         if (!atomic_long_inc_not_zero(&group_leader->refcount))
1965                 return 0;
1966 
1967         /*
1968          * Link aux_outputs to their aux event; this is undone in
1969          * perf_group_detach() by perf_put_aux_event(). When the
1970          * group in torn down, the aux_output events loose their
1971          * link to the aux_event and can't schedule any more.
1972          */
1973         event->aux_event = group_leader;
1974 
1975         return 1;
1976 }
1977 
1978 static void perf_group_detach(struct perf_event *event)
1979 {
1980         struct perf_event *sibling, *tmp;
1981         struct perf_event_context *ctx = event->ctx;
1982 
1983         lockdep_assert_held(&ctx->lock);
1984 
1985         /*
1986          * We can have double detach due to exit/hot-unplug + close.
1987          */
1988         if (!(event->attach_state & PERF_ATTACH_GROUP))
1989                 return;
1990 
1991         event->attach_state &= ~PERF_ATTACH_GROUP;
1992 
1993         perf_put_aux_event(event);
1994 
1995         /*
1996          * If this is a sibling, remove it from its group.
1997          */
1998         if (event->group_leader != event) {
1999                 list_del_init(&event->sibling_list);
2000                 event->group_leader->nr_siblings--;
2001                 goto out;
2002         }
2003 
2004         /*
2005          * If this was a group event with sibling events then
2006          * upgrade the siblings to singleton events by adding them
2007          * to whatever list we are on.
2008          */
2009         list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2010 
2011                 sibling->group_leader = sibling;
2012                 list_del_init(&sibling->sibling_list);
2013 
2014                 /* Inherit group flags from the previous leader */
2015                 sibling->group_caps = event->group_caps;
2016 
2017                 if (!RB_EMPTY_NODE(&event->group_node)) {
2018                         add_event_to_groups(sibling, event->ctx);
2019 
2020                         if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
2021                                 struct list_head *list = sibling->attr.pinned ?
2022                                         &ctx->pinned_active : &ctx->flexible_active;
2023 
2024                                 list_add_tail(&sibling->active_list, list);
2025                         }
2026                 }
2027 
2028                 WARN_ON_ONCE(sibling->ctx != event->ctx);
2029         }
2030 
2031 out:
2032         perf_event__header_size(event->group_leader);
2033 
2034         for_each_sibling_event(tmp, event->group_leader)
2035                 perf_event__header_size(tmp);
2036 }
2037 
2038 static bool is_orphaned_event(struct perf_event *event)
2039 {
2040         return event->state == PERF_EVENT_STATE_DEAD;
2041 }
2042 
2043 static inline int __pmu_filter_match(struct perf_event *event)
2044 {
2045         struct pmu *pmu = event->pmu;
2046         return pmu->filter_match ? pmu->filter_match(event) : 1;
2047 }
2048 
2049 /*
2050  * Check whether we should attempt to schedule an event group based on
2051  * PMU-specific filtering. An event group can consist of HW and SW events,
2052  * potentially with a SW leader, so we must check all the filters, to
2053  * determine whether a group is schedulable:
2054  */
2055 static inline int pmu_filter_match(struct perf_event *event)
2056 {
2057         struct perf_event *sibling;
2058 
2059         if (!__pmu_filter_match(event))
2060                 return 0;
2061 
2062         for_each_sibling_event(sibling, event) {
2063                 if (!__pmu_filter_match(sibling))
2064                         return 0;
2065         }
2066 
2067         return 1;
2068 }
2069 
2070 static inline int
2071 event_filter_match(struct perf_event *event)
2072 {
2073         return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2074                perf_cgroup_match(event) && pmu_filter_match(event);
2075 }
2076 
2077 static void
2078 event_sched_out(struct perf_event *event,
2079                   struct perf_cpu_context *cpuctx,
2080                   struct perf_event_context *ctx)
2081 {
2082         enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2083 
2084         WARN_ON_ONCE(event->ctx != ctx);
2085         lockdep_assert_held(&ctx->lock);
2086 
2087         if (event->state != PERF_EVENT_STATE_ACTIVE)
2088                 return;
2089 
2090         /*
2091          * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2092          * we can schedule events _OUT_ individually through things like
2093          * __perf_remove_from_context().
2094          */
2095         list_del_init(&event->active_list);
2096 
2097         perf_pmu_disable(event->pmu);
2098 
2099         event->pmu->del(event, 0);
2100         event->oncpu = -1;
2101 
2102         if (READ_ONCE(event->pending_disable) >= 0) {
2103                 WRITE_ONCE(event->pending_disable, -1);
2104                 state = PERF_EVENT_STATE_OFF;
2105         }
2106         perf_event_set_state(event, state);
2107 
2108         if (!is_software_event(event))
2109                 cpuctx->active_oncpu--;
2110         if (!--ctx->nr_active)
2111                 perf_event_ctx_deactivate(ctx);
2112         if (event->attr.freq && event->attr.sample_freq)
2113                 ctx->nr_freq--;
2114         if (event->attr.exclusive || !cpuctx->active_oncpu)
2115                 cpuctx->exclusive = 0;
2116 
2117         perf_pmu_enable(event->pmu);
2118 }
2119 
2120 static void
2121 group_sched_out(struct perf_event *group_event,
2122                 struct perf_cpu_context *cpuctx,
2123                 struct perf_event_context *ctx)
2124 {
2125         struct perf_event *event;
2126 
2127         if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2128                 return;
2129 
2130         perf_pmu_disable(ctx->pmu);
2131 
2132         event_sched_out(group_event, cpuctx, ctx);
2133 
2134         /*
2135          * Schedule out siblings (if any):
2136          */
2137         for_each_sibling_event(event, group_event)
2138                 event_sched_out(event, cpuctx, ctx);
2139 
2140         perf_pmu_enable(ctx->pmu);
2141 
2142         if (group_event->attr.exclusive)
2143                 cpuctx->exclusive = 0;
2144 }
2145 
2146 #define DETACH_GROUP    0x01UL
2147 
2148 /*
2149  * Cross CPU call to remove a performance event
2150  *
2151  * We disable the event on the hardware level first. After that we
2152  * remove it from the context list.
2153  */
2154 static void
2155 __perf_remove_from_context(struct perf_event *event,
2156                            struct perf_cpu_context *cpuctx,
2157                            struct perf_event_context *ctx,
2158                            void *info)
2159 {
2160         unsigned long flags = (unsigned long)info;
2161 
2162         if (ctx->is_active & EVENT_TIME) {
2163                 update_context_time(ctx);
2164                 update_cgrp_time_from_cpuctx(cpuctx);
2165         }
2166 
2167         event_sched_out(event, cpuctx, ctx);
2168         if (flags & DETACH_GROUP)
2169                 perf_group_detach(event);
2170         list_del_event(event, ctx);
2171 
2172         if (!ctx->nr_events && ctx->is_active) {
2173                 ctx->is_active = 0;
2174                 if (ctx->task) {
2175                         WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2176                         cpuctx->task_ctx = NULL;
2177                 }
2178         }
2179 }
2180 
2181 /*
2182  * Remove the event from a task's (or a CPU's) list of events.
2183  *
2184  * If event->ctx is a cloned context, callers must make sure that
2185  * every task struct that event->ctx->task could possibly point to
2186  * remains valid.  This is OK when called from perf_release since
2187  * that only calls us on the top-level context, which can't be a clone.
2188  * When called from perf_event_exit_task, it's OK because the
2189  * context has been detached from its task.
2190  */
2191 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2192 {
2193         struct perf_event_context *ctx = event->ctx;
2194 
2195         lockdep_assert_held(&ctx->mutex);
2196 
2197         event_function_call(event, __perf_remove_from_context, (void *)flags);
2198 
2199         /*
2200          * The above event_function_call() can NO-OP when it hits
2201          * TASK_TOMBSTONE. In that case we must already have been detached
2202          * from the context (by perf_event_exit_event()) but the grouping
2203          * might still be in-tact.
2204          */
2205         WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2206         if ((flags & DETACH_GROUP) &&
2207             (event->attach_state & PERF_ATTACH_GROUP)) {
2208                 /*
2209                  * Since in that case we cannot possibly be scheduled, simply
2210                  * detach now.
2211                  */
2212                 raw_spin_lock_irq(&ctx->lock);
2213                 perf_group_detach(event);
2214                 raw_spin_unlock_irq(&ctx->lock);
2215         }
2216 }
2217 
2218 /*
2219  * Cross CPU call to disable a performance event
2220  */
2221 static void __perf_event_disable(struct perf_event *event,
2222                                  struct perf_cpu_context *cpuctx,
2223                                  struct perf_event_context *ctx,
2224                                  void *info)
2225 {
2226         if (event->state < PERF_EVENT_STATE_INACTIVE)
2227                 return;
2228 
2229         if (ctx->is_active & EVENT_TIME) {
2230                 update_context_time(ctx);
2231                 update_cgrp_time_from_event(event);
2232         }
2233 
2234         if (event == event->group_leader)
2235                 group_sched_out(event, cpuctx, ctx);
2236         else
2237                 event_sched_out(event, cpuctx, ctx);
2238 
2239         perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2240 }
2241 
2242 /*
2243  * Disable an event.
2244  *
2245  * If event->ctx is a cloned context, callers must make sure that
2246  * every task struct that event->ctx->task could possibly point to
2247  * remains valid.  This condition is satisfied when called through
2248  * perf_event_for_each_child or perf_event_for_each because they
2249  * hold the top-level event's child_mutex, so any descendant that
2250  * goes to exit will block in perf_event_exit_event().
2251  *
2252  * When called from perf_pending_event it's OK because event->ctx
2253  * is the current context on this CPU and preemption is disabled,
2254  * hence we can't get into perf_event_task_sched_out for this context.
2255  */
2256 static void _perf_event_disable(struct perf_event *event)
2257 {
2258         struct perf_event_context *ctx = event->ctx;
2259 
2260         raw_spin_lock_irq(&ctx->lock);
2261         if (event->state <= PERF_EVENT_STATE_OFF) {
2262                 raw_spin_unlock_irq(&ctx->lock);
2263                 return;
2264         }
2265         raw_spin_unlock_irq(&ctx->lock);
2266 
2267         event_function_call(event, __perf_event_disable, NULL);
2268 }
2269 
2270 void perf_event_disable_local(struct perf_event *event)
2271 {
2272         event_function_local(event, __perf_event_disable, NULL);
2273 }
2274 
2275 /*
2276  * Strictly speaking kernel users cannot create groups and therefore this
2277  * interface does not need the perf_event_ctx_lock() magic.
2278  */
2279 void perf_event_disable(struct perf_event *event)
2280 {
2281         struct perf_event_context *ctx;
2282 
2283         ctx = perf_event_ctx_lock(event);
2284         _perf_event_disable(event);
2285         perf_event_ctx_unlock(event, ctx);
2286 }
2287 EXPORT_SYMBOL_GPL(perf_event_disable);
2288 
2289 void perf_event_disable_inatomic(struct perf_event *event)
2290 {
2291         WRITE_ONCE(event->pending_disable, smp_processor_id());
2292         /* can fail, see perf_pending_event_disable() */
2293         irq_work_queue(&event->pending);
2294 }
2295 
2296 static void perf_set_shadow_time(struct perf_event *event,
2297                                  struct perf_event_context *ctx)
2298 {
2299         /*
2300          * use the correct time source for the time snapshot
2301          *
2302          * We could get by without this by leveraging the
2303          * fact that to get to this function, the caller
2304          * has most likely already called update_context_time()
2305          * and update_cgrp_time_xx() and thus both timestamp
2306          * are identical (or very close). Given that tstamp is,
2307          * already adjusted for cgroup, we could say that:
2308          *    tstamp - ctx->timestamp
2309          * is equivalent to
2310          *    tstamp - cgrp->timestamp.
2311          *
2312          * Then, in perf_output_read(), the calculation would
2313          * work with no changes because:
2314          * - event is guaranteed scheduled in
2315          * - no scheduled out in between
2316          * - thus the timestamp would be the same
2317          *
2318          * But this is a bit hairy.
2319          *
2320          * So instead, we have an explicit cgroup call to remain
2321          * within the time time source all along. We believe it
2322          * is cleaner and simpler to understand.
2323          */
2324         if (is_cgroup_event(event))
2325                 perf_cgroup_set_shadow_time(event, event->tstamp);
2326         else
2327                 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2328 }
2329 
2330 #define MAX_INTERRUPTS (~0ULL)
2331 
2332 static void perf_log_throttle(struct perf_event *event, int enable);
2333 static void perf_log_itrace_start(struct perf_event *event);
2334 
2335 static int
2336 event_sched_in(struct perf_event *event,
2337                  struct perf_cpu_context *cpuctx,
2338                  struct perf_event_context *ctx)
2339 {
2340         int ret = 0;
2341 
2342         lockdep_assert_held(&ctx->lock);
2343 
2344         if (event->state <= PERF_EVENT_STATE_OFF)
2345                 return 0;
2346 
2347         WRITE_ONCE(event->oncpu, smp_processor_id());
2348         /*
2349          * Order event::oncpu write to happen before the ACTIVE state is
2350          * visible. This allows perf_event_{stop,read}() to observe the correct
2351          * ->oncpu if it sees ACTIVE.
2352          */
2353         smp_wmb();
2354         perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2355 
2356         /*
2357          * Unthrottle events, since we scheduled we might have missed several
2358          * ticks already, also for a heavily scheduling task there is little
2359          * guarantee it'll get a tick in a timely manner.
2360          */
2361         if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2362                 perf_log_throttle(event, 1);
2363                 event->hw.interrupts = 0;
2364         }
2365 
2366         perf_pmu_disable(event->pmu);
2367 
2368         perf_set_shadow_time(event, ctx);
2369 
2370         perf_log_itrace_start(event);
2371 
2372         if (event->pmu->add(event, PERF_EF_START)) {
2373                 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2374                 event->oncpu = -1;
2375                 ret = -EAGAIN;
2376                 goto out;
2377         }
2378 
2379         if (!is_software_event(event))
2380                 cpuctx->active_oncpu++;
2381         if (!ctx->nr_active++)
2382                 perf_event_ctx_activate(ctx);
2383         if (event->attr.freq && event->attr.sample_freq)
2384                 ctx->nr_freq++;
2385 
2386         if (event->attr.exclusive)
2387                 cpuctx->exclusive = 1;
2388 
2389 out:
2390         perf_pmu_enable(event->pmu);
2391 
2392         return ret;
2393 }
2394 
2395 static int
2396 group_sched_in(struct perf_event *group_event,
2397                struct perf_cpu_context *cpuctx,
2398                struct perf_event_context *ctx)
2399 {
2400         struct perf_event *event, *partial_group = NULL;
2401         struct pmu *pmu = ctx->pmu;
2402 
2403         if (group_event->state == PERF_EVENT_STATE_OFF)
2404                 return 0;
2405 
2406         pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2407 
2408         if (event_sched_in(group_event, cpuctx, ctx)) {
2409                 pmu->cancel_txn(pmu);
2410                 perf_mux_hrtimer_restart(cpuctx);
2411                 return -EAGAIN;
2412         }
2413 
2414         /*
2415          * Schedule in siblings as one group (if any):
2416          */
2417         for_each_sibling_event(event, group_event) {
2418                 if (event_sched_in(event, cpuctx, ctx)) {
2419                         partial_group = event;
2420                         goto group_error;
2421                 }
2422         }
2423 
2424         if (!pmu->commit_txn(pmu))
2425                 return 0;
2426 
2427 group_error:
2428         /*
2429          * Groups can be scheduled in as one unit only, so undo any
2430          * partial group before returning:
2431          * The events up to the failed event are scheduled out normally.
2432          */
2433         for_each_sibling_event(event, group_event) {
2434                 if (event == partial_group)
2435                         break;
2436 
2437                 event_sched_out(event, cpuctx, ctx);
2438         }
2439         event_sched_out(group_event, cpuctx, ctx);
2440 
2441         pmu->cancel_txn(pmu);
2442 
2443         perf_mux_hrtimer_restart(cpuctx);
2444 
2445         return -EAGAIN;
2446 }
2447 
2448 /*
2449  * Work out whether we can put this event group on the CPU now.
2450  */
2451 static int group_can_go_on(struct perf_event *event,
2452                            struct perf_cpu_context *cpuctx,
2453                            int can_add_hw)
2454 {
2455         /*
2456          * Groups consisting entirely of software events can always go on.
2457          */
2458         if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2459                 return 1;
2460         /*
2461          * If an exclusive group is already on, no other hardware
2462          * events can go on.
2463          */
2464         if (cpuctx->exclusive)
2465                 return 0;
2466         /*
2467          * If this group is exclusive and there are already
2468          * events on the CPU, it can't go on.
2469          */
2470         if (event->attr.exclusive && cpuctx->active_oncpu)
2471                 return 0;
2472         /*
2473          * Otherwise, try to add it if all previous groups were able
2474          * to go on.
2475          */
2476         return can_add_hw;
2477 }
2478 
2479 static void add_event_to_ctx(struct perf_event *event,
2480                                struct perf_event_context *ctx)
2481 {
2482         list_add_event(event, ctx);
2483         perf_group_attach(event);
2484 }
2485 
2486 static void ctx_sched_out(struct perf_event_context *ctx,
2487                           struct perf_cpu_context *cpuctx,
2488                           enum event_type_t event_type);
2489 static void
2490 ctx_sched_in(struct perf_event_context *ctx,
2491              struct perf_cpu_context *cpuctx,
2492              enum event_type_t event_type,
2493              struct task_struct *task);
2494 
2495 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2496                                struct perf_event_context *ctx,
2497                                enum event_type_t event_type)
2498 {
2499         if (!cpuctx->task_ctx)
2500                 return;
2501 
2502         if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2503                 return;
2504 
2505         ctx_sched_out(ctx, cpuctx, event_type);
2506 }
2507 
2508 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2509                                 struct perf_event_context *ctx,
2510                                 struct task_struct *task)
2511 {
2512         cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2513         if (ctx)
2514                 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2515         cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2516         if (ctx)
2517                 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2518 }
2519 
2520 /*
2521  * We want to maintain the following priority of scheduling:
2522  *  - CPU pinned (EVENT_CPU | EVENT_PINNED)
2523  *  - task pinned (EVENT_PINNED)
2524  *  - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2525  *  - task flexible (EVENT_FLEXIBLE).
2526  *
2527  * In order to avoid unscheduling and scheduling back in everything every
2528  * time an event is added, only do it for the groups of equal priority and
2529  * below.
2530  *
2531  * This can be called after a batch operation on task events, in which case
2532  * event_type is a bit mask of the types of events involved. For CPU events,
2533  * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2534  */
2535 static void ctx_resched(struct perf_cpu_context *cpuctx,
2536                         struct perf_event_context *task_ctx,
2537                         enum event_type_t event_type)
2538 {
2539         enum event_type_t ctx_event_type;
2540         bool cpu_event = !!(event_type & EVENT_CPU);
2541 
2542         /*
2543          * If pinned groups are involved, flexible groups also need to be
2544          * scheduled out.
2545          */
2546         if (event_type & EVENT_PINNED)
2547                 event_type |= EVENT_FLEXIBLE;
2548 
2549         ctx_event_type = event_type & EVENT_ALL;
2550 
2551         perf_pmu_disable(cpuctx->ctx.pmu);
2552         if (task_ctx)
2553                 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2554 
2555         /*
2556          * Decide which cpu ctx groups to schedule out based on the types
2557          * of events that caused rescheduling:
2558          *  - EVENT_CPU: schedule out corresponding groups;
2559          *  - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2560          *  - otherwise, do nothing more.
2561          */
2562         if (cpu_event)
2563                 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2564         else if (ctx_event_type & EVENT_PINNED)
2565                 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2566 
2567         perf_event_sched_in(cpuctx, task_ctx, current);
2568         perf_pmu_enable(cpuctx->ctx.pmu);
2569 }
2570 
2571 void perf_pmu_resched(struct pmu *pmu)
2572 {
2573         struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2574         struct perf_event_context *task_ctx = cpuctx->task_ctx;
2575 
2576         perf_ctx_lock(cpuctx, task_ctx);
2577         ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2578         perf_ctx_unlock(cpuctx, task_ctx);
2579 }
2580 
2581 /*
2582  * Cross CPU call to install and enable a performance event
2583  *
2584  * Very similar to remote_function() + event_function() but cannot assume that
2585  * things like ctx->is_active and cpuctx->task_ctx are set.
2586  */
2587 static int  __perf_install_in_context(void *info)
2588 {
2589         struct perf_event *event = info;
2590         struct perf_event_context *ctx = event->ctx;
2591         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2592         struct perf_event_context *task_ctx = cpuctx->task_ctx;
2593         bool reprogram = true;
2594         int ret = 0;
2595 
2596         raw_spin_lock(&cpuctx->ctx.lock);
2597         if (ctx->task) {
2598                 raw_spin_lock(&ctx->lock);
2599                 task_ctx = ctx;
2600 
2601                 reprogram = (ctx->task == current);
2602 
2603                 /*
2604                  * If the task is running, it must be running on this CPU,
2605                  * otherwise we cannot reprogram things.
2606                  *
2607                  * If its not running, we don't care, ctx->lock will
2608                  * serialize against it becoming runnable.
2609                  */
2610                 if (task_curr(ctx->task) && !reprogram) {
2611                         ret = -ESRCH;
2612                         goto unlock;
2613                 }
2614 
2615                 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2616         } else if (task_ctx) {
2617                 raw_spin_lock(&task_ctx->lock);
2618         }
2619 
2620 #ifdef CONFIG_CGROUP_PERF
2621         if (is_cgroup_event(event)) {
2622                 /*
2623                  * If the current cgroup doesn't match the event's
2624                  * cgroup, we should not try to schedule it.
2625                  */
2626                 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2627                 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2628                                         event->cgrp->css.cgroup);
2629         }
2630 #endif
2631 
2632         if (reprogram) {
2633                 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2634                 add_event_to_ctx(event, ctx);
2635                 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2636         } else {
2637                 add_event_to_ctx(event, ctx);
2638         }
2639 
2640 unlock:
2641         perf_ctx_unlock(cpuctx, task_ctx);
2642 
2643         return ret;
2644 }
2645 
2646 static bool exclusive_event_installable(struct perf_event *event,
2647                                         struct perf_event_context *ctx);
2648 
2649 /*
2650  * Attach a performance event to a context.
2651  *
2652  * Very similar to event_function_call, see comment there.
2653  */
2654 static void
2655 perf_install_in_context(struct perf_event_context *ctx,
2656                         struct perf_event *event,
2657                         int cpu)
2658 {
2659         struct task_struct *task = READ_ONCE(ctx->task);
2660 
2661         lockdep_assert_held(&ctx->mutex);
2662 
2663         WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2664 
2665         if (event->cpu != -1)
2666                 event->cpu = cpu;
2667 
2668         /*
2669          * Ensures that if we can observe event->ctx, both the event and ctx
2670          * will be 'complete'. See perf_iterate_sb_cpu().
2671          */
2672         smp_store_release(&event->ctx, ctx);
2673 
2674         if (!task) {
2675                 cpu_function_call(cpu, __perf_install_in_context, event);
2676                 return;
2677         }
2678 
2679         /*
2680          * Should not happen, we validate the ctx is still alive before calling.
2681          */
2682         if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2683                 return;
2684 
2685         /*
2686          * Installing events is tricky because we cannot rely on ctx->is_active
2687          * to be set in case this is the nr_events 0 -> 1 transition.
2688          *
2689          * Instead we use task_curr(), which tells us if the task is running.
2690          * However, since we use task_curr() outside of rq::lock, we can race
2691          * against the actual state. This means the result can be wrong.
2692          *
2693          * If we get a false positive, we retry, this is harmless.
2694          *
2695          * If we get a false negative, things are complicated. If we are after
2696          * perf_event_context_sched_in() ctx::lock will serialize us, and the
2697          * value must be correct. If we're before, it doesn't matter since
2698          * perf_event_context_sched_in() will program the counter.
2699          *
2700          * However, this hinges on the remote context switch having observed
2701          * our task->perf_event_ctxp[] store, such that it will in fact take
2702          * ctx::lock in perf_event_context_sched_in().
2703          *
2704          * We do this by task_function_call(), if the IPI fails to hit the task
2705          * we know any future context switch of task must see the
2706          * perf_event_ctpx[] store.
2707          */
2708 
2709         /*
2710          * This smp_mb() orders the task->perf_event_ctxp[] store with the
2711          * task_cpu() load, such that if the IPI then does not find the task
2712          * running, a future context switch of that task must observe the
2713          * store.
2714          */
2715         smp_mb();
2716 again:
2717         if (!task_function_call(task, __perf_install_in_context, event))
2718                 return;
2719 
2720         raw_spin_lock_irq(&ctx->lock);
2721         task = ctx->task;
2722         if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2723                 /*
2724                  * Cannot happen because we already checked above (which also
2725                  * cannot happen), and we hold ctx->mutex, which serializes us
2726                  * against perf_event_exit_task_context().
2727                  */
2728                 raw_spin_unlock_irq(&ctx->lock);
2729                 return;
2730         }
2731         /*
2732          * If the task is not running, ctx->lock will avoid it becoming so,
2733          * thus we can safely install the event.
2734          */
2735         if (task_curr(task)) {
2736                 raw_spin_unlock_irq(&ctx->lock);
2737                 goto again;
2738         }
2739         add_event_to_ctx(event, ctx);
2740         raw_spin_unlock_irq(&ctx->lock);
2741 }
2742 
2743 /*
2744  * Cross CPU call to enable a performance event
2745  */
2746 static void __perf_event_enable(struct perf_event *event,
2747                                 struct perf_cpu_context *cpuctx,
2748                                 struct perf_event_context *ctx,
2749                                 void *info)
2750 {
2751         struct perf_event *leader = event->group_leader;
2752         struct perf_event_context *task_ctx;
2753 
2754         if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2755             event->state <= PERF_EVENT_STATE_ERROR)
2756                 return;
2757 
2758         if (ctx->is_active)
2759                 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2760 
2761         perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2762 
2763         if (!ctx->is_active)
2764                 return;
2765 
2766         if (!event_filter_match(event)) {
2767                 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2768                 return;
2769         }
2770 
2771         /*
2772          * If the event is in a group and isn't the group leader,
2773          * then don't put it on unless the group is on.
2774          */
2775         if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2776                 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2777                 return;
2778         }
2779 
2780         task_ctx = cpuctx->task_ctx;
2781         if (ctx->task)
2782                 WARN_ON_ONCE(task_ctx != ctx);
2783 
2784         ctx_resched(cpuctx, task_ctx, get_event_type(event));
2785 }
2786 
2787 /*
2788  * Enable an event.
2789  *
2790  * If event->ctx is a cloned context, callers must make sure that
2791  * every task struct that event->ctx->task could possibly point to
2792  * remains valid.  This condition is satisfied when called through
2793  * perf_event_for_each_child or perf_event_for_each as described
2794  * for perf_event_disable.
2795  */
2796 static void _perf_event_enable(struct perf_event *event)
2797 {
2798         struct perf_event_context *ctx = event->ctx;
2799 
2800         raw_spin_lock_irq(&ctx->lock);
2801         if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2802             event->state <  PERF_EVENT_STATE_ERROR) {
2803                 raw_spin_unlock_irq(&ctx->lock);
2804                 return;
2805         }
2806 
2807         /*
2808          * If the event is in error state, clear that first.
2809          *
2810          * That way, if we see the event in error state below, we know that it
2811          * has gone back into error state, as distinct from the task having
2812          * been scheduled away before the cross-call arrived.
2813          */
2814         if (event->state == PERF_EVENT_STATE_ERROR)
2815                 event->state = PERF_EVENT_STATE_OFF;
2816         raw_spin_unlock_irq(&ctx->lock);
2817 
2818         event_function_call(event, __perf_event_enable, NULL);
2819 }
2820 
2821 /*
2822  * See perf_event_disable();
2823  */
2824 void perf_event_enable(struct perf_event *event)
2825 {
2826         struct perf_event_context *ctx;
2827 
2828         ctx = perf_event_ctx_lock(event);
2829         _perf_event_enable(event);
2830         perf_event_ctx_unlock(event, ctx);
2831 }
2832 EXPORT_SYMBOL_GPL(perf_event_enable);
2833 
2834 struct stop_event_data {
2835         struct perf_event       *event;
2836         unsigned int            restart;
2837 };
2838 
2839 static int __perf_event_stop(void *info)
2840 {
2841         struct stop_event_data *sd = info;
2842         struct perf_event *event = sd->event;
2843 
2844         /* if it's already INACTIVE, do nothing */
2845         if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2846                 return 0;
2847 
2848         /* matches smp_wmb() in event_sched_in() */
2849         smp_rmb();
2850 
2851         /*
2852          * There is a window with interrupts enabled before we get here,
2853          * so we need to check again lest we try to stop another CPU's event.
2854          */
2855         if (READ_ONCE(event->oncpu) != smp_processor_id())
2856                 return -EAGAIN;
2857 
2858         event->pmu->stop(event, PERF_EF_UPDATE);
2859 
2860         /*
2861          * May race with the actual stop (through perf_pmu_output_stop()),
2862          * but it is only used for events with AUX ring buffer, and such
2863          * events will refuse to restart because of rb::aux_mmap_count==0,
2864          * see comments in perf_aux_output_begin().
2865          *
2866          * Since this is happening on an event-local CPU, no trace is lost
2867          * while restarting.
2868          */
2869         if (sd->restart)
2870                 event->pmu->start(event, 0);
2871 
2872         return 0;
2873 }
2874 
2875 static int perf_event_stop(struct perf_event *event, int restart)
2876 {
2877         struct stop_event_data sd = {
2878                 .event          = event,
2879                 .restart        = restart,
2880         };
2881         int ret = 0;
2882 
2883         do {
2884                 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2885                         return 0;
2886 
2887                 /* matches smp_wmb() in event_sched_in() */
2888                 smp_rmb();
2889 
2890                 /*
2891                  * We only want to restart ACTIVE events, so if the event goes
2892                  * inactive here (event->oncpu==-1), there's nothing more to do;
2893                  * fall through with ret==-ENXIO.
2894                  */
2895                 ret = cpu_function_call(READ_ONCE(event->oncpu),
2896                                         __perf_event_stop, &sd);
2897         } while (ret == -EAGAIN);
2898 
2899         return ret;
2900 }
2901 
2902 /*
2903  * In order to contain the amount of racy and tricky in the address filter
2904  * configuration management, it is a two part process:
2905  *
2906  * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2907  *      we update the addresses of corresponding vmas in
2908  *      event::addr_filter_ranges array and bump the event::addr_filters_gen;
2909  * (p2) when an event is scheduled in (pmu::add), it calls
2910  *      perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2911  *      if the generation has changed since the previous call.
2912  *
2913  * If (p1) happens while the event is active, we restart it to force (p2).
2914  *
2915  * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2916  *     pre-existing mappings, called once when new filters arrive via SET_FILTER
2917  *     ioctl;
2918  * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2919  *     registered mapping, called for every new mmap(), with mm::mmap_sem down
2920  *     for reading;
2921  * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2922  *     of exec.
2923  */
2924 void perf_event_addr_filters_sync(struct perf_event *event)
2925 {
2926         struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2927 
2928         if (!has_addr_filter(event))
2929                 return;
2930 
2931         raw_spin_lock(&ifh->lock);
2932         if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2933                 event->pmu->addr_filters_sync(event);
2934                 event->hw.addr_filters_gen = event->addr_filters_gen;
2935         }
2936         raw_spin_unlock(&ifh->lock);
2937 }
2938 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2939 
2940 static int _perf_event_refresh(struct perf_event *event, int refresh)
2941 {
2942         /*
2943          * not supported on inherited events
2944          */
2945         if (event->attr.inherit || !is_sampling_event(event))
2946                 return -EINVAL;
2947 
2948         atomic_add(refresh, &event->event_limit);
2949         _perf_event_enable(event);
2950 
2951         return 0;
2952 }
2953 
2954 /*
2955  * See perf_event_disable()
2956  */
2957 int perf_event_refresh(struct perf_event *event, int refresh)
2958 {
2959         struct perf_event_context *ctx;
2960         int ret;
2961 
2962         ctx = perf_event_ctx_lock(event);
2963         ret = _perf_event_refresh(event, refresh);
2964         perf_event_ctx_unlock(event, ctx);
2965 
2966         return ret;
2967 }
2968 EXPORT_SYMBOL_GPL(perf_event_refresh);
2969 
2970 static int perf_event_modify_breakpoint(struct perf_event *bp,
2971                                          struct perf_event_attr *attr)
2972 {
2973         int err;
2974 
2975         _perf_event_disable(bp);
2976 
2977         err = modify_user_hw_breakpoint_check(bp, attr, true);
2978 
2979         if (!bp->attr.disabled)
2980                 _perf_event_enable(bp);
2981 
2982         return err;
2983 }
2984 
2985 static int perf_event_modify_attr(struct perf_event *event,
2986                                   struct perf_event_attr *attr)
2987 {
2988         if (event->attr.type != attr->type)
2989                 return -EINVAL;
2990 
2991         switch (event->attr.type) {
2992         case PERF_TYPE_BREAKPOINT:
2993                 return perf_event_modify_breakpoint(event, attr);
2994         default:
2995                 /* Place holder for future additions. */
2996                 return -EOPNOTSUPP;
2997         }
2998 }
2999 
3000 static void ctx_sched_out(struct perf_event_context *ctx,
3001                           struct perf_cpu_context *cpuctx,
3002                           enum event_type_t event_type)
3003 {
3004         struct perf_event *event, *tmp;
3005         int is_active = ctx->is_active;
3006 
3007         lockdep_assert_held(&ctx->lock);
3008 
3009         if (likely(!ctx->nr_events)) {
3010                 /*
3011                  * See __perf_remove_from_context().
3012                  */
3013                 WARN_ON_ONCE(ctx->is_active);
3014                 if (ctx->task)
3015                         WARN_ON_ONCE(cpuctx->task_ctx);
3016                 return;
3017         }
3018 
3019         ctx->is_active &= ~event_type;
3020         if (!(ctx->is_active & EVENT_ALL))
3021                 ctx->is_active = 0;
3022 
3023         if (ctx->task) {
3024                 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3025                 if (!ctx->is_active)
3026                         cpuctx->task_ctx = NULL;
3027         }
3028 
3029         /*
3030          * Always update time if it was set; not only when it changes.
3031          * Otherwise we can 'forget' to update time for any but the last
3032          * context we sched out. For example:
3033          *
3034          *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3035          *   ctx_sched_out(.event_type = EVENT_PINNED)
3036          *
3037          * would only update time for the pinned events.
3038          */
3039         if (is_active & EVENT_TIME) {
3040                 /* update (and stop) ctx time */
3041                 update_context_time(ctx);
3042                 update_cgrp_time_from_cpuctx(cpuctx);
3043         }
3044 
3045         is_active ^= ctx->is_active; /* changed bits */
3046 
3047         if (!ctx->nr_active || !(is_active & EVENT_ALL))
3048                 return;
3049 
3050         /*
3051          * If we had been multiplexing, no rotations are necessary, now no events
3052          * are active.
3053          */
3054         ctx->rotate_necessary = 0;
3055 
3056         perf_pmu_disable(ctx->pmu);
3057         if (is_active & EVENT_PINNED) {
3058                 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3059                         group_sched_out(event, cpuctx, ctx);
3060         }
3061 
3062         if (is_active & EVENT_FLEXIBLE) {
3063                 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3064                         group_sched_out(event, cpuctx, ctx);
3065         }
3066         perf_pmu_enable(ctx->pmu);
3067 }
3068 
3069 /*
3070  * Test whether two contexts are equivalent, i.e. whether they have both been
3071  * cloned from the same version of the same context.
3072  *
3073  * Equivalence is measured using a generation number in the context that is
3074  * incremented on each modification to it; see unclone_ctx(), list_add_event()
3075  * and list_del_event().
3076  */
3077 static int context_equiv(struct perf_event_context *ctx1,
3078                          struct perf_event_context *ctx2)
3079 {
3080         lockdep_assert_held(&ctx1->lock);
3081         lockdep_assert_held(&ctx2->lock);
3082 
3083         /* Pinning disables the swap optimization */
3084         if (ctx1->pin_count || ctx2->pin_count)
3085                 return 0;
3086 
3087         /* If ctx1 is the parent of ctx2 */
3088         if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3089                 return 1;
3090 
3091         /* If ctx2 is the parent of ctx1 */
3092         if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3093                 return 1;
3094 
3095         /*
3096          * If ctx1 and ctx2 have the same parent; we flatten the parent
3097          * hierarchy, see perf_event_init_context().
3098          */
3099         if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3100                         ctx1->parent_gen == ctx2->parent_gen)
3101                 return 1;
3102 
3103         /* Unmatched */
3104         return 0;
3105 }
3106 
3107 static void __perf_event_sync_stat(struct perf_event *event,
3108                                      struct perf_event *next_event)
3109 {
3110         u64 value;
3111 
3112         if (!event->attr.inherit_stat)
3113                 return;
3114 
3115         /*
3116          * Update the event value, we cannot use perf_event_read()
3117          * because we're in the middle of a context switch and have IRQs
3118          * disabled, which upsets smp_call_function_single(), however
3119          * we know the event must be on the current CPU, therefore we
3120          * don't need to use it.
3121          */
3122         if (event->state == PERF_EVENT_STATE_ACTIVE)
3123                 event->pmu->read(event);
3124 
3125         perf_event_update_time(event);
3126 
3127         /*
3128          * In order to keep per-task stats reliable we need to flip the event
3129          * values when we flip the contexts.
3130          */
3131         value = local64_read(&next_event->count);
3132         value = local64_xchg(&event->count, value);
3133         local64_set(&next_event->count, value);
3134 
3135         swap(event->total_time_enabled, next_event->total_time_enabled);
3136         swap(event->total_time_running, next_event->total_time_running);
3137 
3138         /*
3139          * Since we swizzled the values, update the user visible data too.
3140          */
3141         perf_event_update_userpage(event);
3142         perf_event_update_userpage(next_event);
3143 }
3144 
3145 static void perf_event_sync_stat(struct perf_event_context *ctx,
3146                                    struct perf_event_context *next_ctx)
3147 {
3148         struct perf_event *event, *next_event;
3149 
3150         if (!ctx->nr_stat)
3151                 return;
3152 
3153         update_context_time(ctx);
3154 
3155         event = list_first_entry(&ctx->event_list,
3156                                    struct perf_event, event_entry);
3157 
3158         next_event = list_first_entry(&next_ctx->event_list,
3159                                         struct perf_event, event_entry);
3160 
3161         while (&event->event_entry != &ctx->event_list &&
3162                &next_event->event_entry != &next_ctx->event_list) {
3163 
3164                 __perf_event_sync_stat(event, next_event);
3165 
3166                 event = list_next_entry(event, event_entry);
3167                 next_event = list_next_entry(next_event, event_entry);
3168         }
3169 }
3170 
3171 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3172                                          struct task_struct *next)
3173 {
3174         struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3175         struct perf_event_context *next_ctx;
3176         struct perf_event_context *parent, *next_parent;
3177         struct perf_cpu_context *cpuctx;
3178         int do_switch = 1;
3179 
3180         if (likely(!ctx))
3181                 return;
3182 
3183         cpuctx = __get_cpu_context(ctx);
3184         if (!cpuctx->task_ctx)
3185                 return;
3186 
3187         rcu_read_lock();
3188         next_ctx = next->perf_event_ctxp[ctxn];
3189         if (!next_ctx)
3190                 goto unlock;
3191 
3192         parent = rcu_dereference(ctx->parent_ctx);
3193         next_parent = rcu_dereference(next_ctx->parent_ctx);
3194 
3195         /* If neither context have a parent context; they cannot be clones. */
3196         if (!parent && !next_parent)
3197                 goto unlock;
3198 
3199         if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3200                 /*
3201                  * Looks like the two contexts are clones, so we might be
3202                  * able to optimize the context switch.  We lock both
3203                  * contexts and check that they are clones under the
3204                  * lock (including re-checking that neither has been
3205                  * uncloned in the meantime).  It doesn't matter which
3206                  * order we take the locks because no other cpu could
3207                  * be trying to lock both of these tasks.
3208                  */
3209                 raw_spin_lock(&ctx->lock);
3210                 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3211                 if (context_equiv(ctx, next_ctx)) {
3212                         WRITE_ONCE(ctx->task, next);
3213                         WRITE_ONCE(next_ctx->task, task);
3214 
3215                         swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3216 
3217                         /*
3218                          * RCU_INIT_POINTER here is safe because we've not
3219                          * modified the ctx and the above modification of
3220                          * ctx->task and ctx->task_ctx_data are immaterial
3221                          * since those values are always verified under
3222                          * ctx->lock which we're now holding.
3223                          */
3224                         RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3225                         RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3226 
3227                         do_switch = 0;
3228 
3229                         perf_event_sync_stat(ctx, next_ctx);
3230                 }
3231                 raw_spin_unlock(&next_ctx->lock);
3232                 raw_spin_unlock(&ctx->lock);
3233         }
3234 unlock:
3235         rcu_read_unlock();
3236 
3237         if (do_switch) {
3238                 raw_spin_lock(&ctx->lock);
3239                 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3240                 raw_spin_unlock(&ctx->lock);
3241         }
3242 }
3243 
3244 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3245 
3246 void perf_sched_cb_dec(struct pmu *pmu)
3247 {
3248         struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3249 
3250         this_cpu_dec(perf_sched_cb_usages);
3251 
3252         if (!--cpuctx->sched_cb_usage)
3253                 list_del(&cpuctx->sched_cb_entry);
3254 }
3255 
3256 
3257 void perf_sched_cb_inc(struct pmu *pmu)
3258 {
3259         struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3260 
3261         if (!cpuctx->sched_cb_usage++)
3262                 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3263 
3264         this_cpu_inc(perf_sched_cb_usages);
3265 }
3266 
3267 /*
3268  * This function provides the context switch callback to the lower code
3269  * layer. It is invoked ONLY when the context switch callback is enabled.
3270  *
3271  * This callback is relevant even to per-cpu events; for example multi event
3272  * PEBS requires this to provide PID/TID information. This requires we flush
3273  * all queued PEBS records before we context switch to a new task.
3274  */
3275 static void perf_pmu_sched_task(struct task_struct *prev,
3276                                 struct task_struct *next,
3277                                 bool sched_in)
3278 {
3279         struct perf_cpu_context *cpuctx;
3280         struct pmu *pmu;
3281 
3282         if (prev == next)
3283                 return;
3284 
3285         list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3286                 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3287 
3288                 if (WARN_ON_ONCE(!pmu->sched_task))
3289                         continue;
3290 
3291                 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3292                 perf_pmu_disable(pmu);
3293 
3294                 pmu->sched_task(cpuctx->task_ctx, sched_in);
3295 
3296                 perf_pmu_enable(pmu);
3297                 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3298         }
3299 }
3300 
3301 static void perf_event_switch(struct task_struct *task,
3302                               struct task_struct *next_prev, bool sched_in);
3303 
3304 #define for_each_task_context_nr(ctxn)                                  \
3305         for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3306 
3307 /*
3308  * Called from scheduler to remove the events of the current task,
3309  * with interrupts disabled.
3310  *
3311  * We stop each event and update the event value in event->count.
3312  *
3313  * This does not protect us against NMI, but disable()
3314  * sets the disabled bit in the control field of event _before_
3315  * accessing the event control register. If a NMI hits, then it will
3316  * not restart the event.
3317  */
3318 void __perf_event_task_sched_out(struct task_struct *task,
3319                                  struct task_struct *next)
3320 {
3321         int ctxn;
3322 
3323         if (__this_cpu_read(perf_sched_cb_usages))
3324                 perf_pmu_sched_task(task, next, false);
3325 
3326         if (atomic_read(&nr_switch_events))
3327                 perf_event_switch(task, next, false);
3328 
3329         for_each_task_context_nr(ctxn)
3330                 perf_event_context_sched_out(task, ctxn, next);
3331 
3332         /*
3333          * if cgroup events exist on this CPU, then we need
3334          * to check if we have to switch out PMU state.
3335          * cgroup event are system-wide mode only
3336          */
3337         if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3338                 perf_cgroup_sched_out(task, next);
3339 }
3340 
3341 /*
3342  * Called with IRQs disabled
3343  */
3344 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3345                               enum event_type_t event_type)
3346 {
3347         ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3348 }
3349 
3350 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3351                               int (*func)(struct perf_event *, void *), void *data)
3352 {
3353         struct perf_event **evt, *evt1, *evt2;
3354         int ret;
3355 
3356         evt1 = perf_event_groups_first(groups, -1);
3357         evt2 = perf_event_groups_first(groups, cpu);
3358 
3359         while (evt1 || evt2) {
3360                 if (evt1 && evt2) {
3361                         if (evt1->group_index < evt2->group_index)
3362                                 evt = &evt1;
3363                         else
3364                                 evt = &evt2;
3365                 } else if (evt1) {
3366                         evt = &evt1;
3367                 } else {
3368                         evt = &evt2;
3369                 }
3370 
3371                 ret = func(*evt, data);
3372                 if (ret)
3373                         return ret;
3374 
3375                 *evt = perf_event_groups_next(*evt);
3376         }
3377 
3378         return 0;
3379 }
3380 
3381 struct sched_in_data {
3382         struct perf_event_context *ctx;
3383         struct perf_cpu_context *cpuctx;
3384         int can_add_hw;
3385 };
3386 
3387 static int pinned_sched_in(struct perf_event *event, void *data)
3388 {
3389         struct sched_in_data *sid = data;
3390 
3391         if (event->state <= PERF_EVENT_STATE_OFF)
3392                 return 0;
3393 
3394         if (!event_filter_match(event))
3395                 return 0;
3396 
3397         if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3398                 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3399                         list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3400         }
3401 
3402         /*
3403          * If this pinned group hasn't been scheduled,
3404          * put it in error state.
3405          */
3406         if (event->state == PERF_EVENT_STATE_INACTIVE)
3407                 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3408 
3409         return 0;
3410 }
3411 
3412 static int flexible_sched_in(struct perf_event *event, void *data)
3413 {
3414         struct sched_in_data *sid = data;
3415 
3416         if (event->state <= PERF_EVENT_STATE_OFF)
3417                 return 0;
3418 
3419         if (!event_filter_match(event))
3420                 return 0;
3421 
3422         if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3423                 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3424                 if (ret) {
3425                         sid->can_add_hw = 0;
3426                         sid->ctx->rotate_necessary = 1;
3427                         return 0;
3428                 }
3429                 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3430         }
3431 
3432         return 0;
3433 }
3434 
3435 static void
3436 ctx_pinned_sched_in(struct perf_event_context *ctx,
3437                     struct perf_cpu_context *cpuctx)
3438 {
3439         struct sched_in_data sid = {
3440                 .ctx = ctx,
3441                 .cpuctx = cpuctx,
3442                 .can_add_hw = 1,
3443         };
3444 
3445         visit_groups_merge(&ctx->pinned_groups,
3446                            smp_processor_id(),
3447                            pinned_sched_in, &sid);
3448 }
3449 
3450 static void
3451 ctx_flexible_sched_in(struct perf_event_context *ctx,
3452                       struct perf_cpu_context *cpuctx)
3453 {
3454         struct sched_in_data sid = {
3455                 .ctx = ctx,
3456                 .cpuctx = cpuctx,
3457                 .can_add_hw = 1,
3458         };
3459 
3460         visit_groups_merge(&ctx->flexible_groups,
3461                            smp_processor_id(),
3462                            flexible_sched_in, &sid);
3463 }
3464 
3465 static void
3466 ctx_sched_in(struct perf_event_context *ctx,
3467              struct perf_cpu_context *cpuctx,
3468              enum event_type_t event_type,
3469              struct task_struct *task)
3470 {
3471         int is_active = ctx->is_active;
3472         u64 now;
3473 
3474         lockdep_assert_held(&ctx->lock);
3475 
3476         if (likely(!ctx->nr_events))
3477                 return;
3478 
3479         ctx->is_active |= (event_type | EVENT_TIME);
3480         if (ctx->task) {
3481                 if (!is_active)
3482                         cpuctx->task_ctx = ctx;
3483                 else
3484                         WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3485         }
3486 
3487         is_active ^= ctx->is_active; /* changed bits */
3488 
3489         if (is_active & EVENT_TIME) {
3490                 /* start ctx time */
3491                 now = perf_clock();
3492                 ctx->timestamp = now;
3493                 perf_cgroup_set_timestamp(task, ctx);
3494         }
3495 
3496         /*
3497          * First go through the list and put on any pinned groups
3498          * in order to give them the best chance of going on.
3499          */
3500         if (is_active & EVENT_PINNED)
3501                 ctx_pinned_sched_in(ctx, cpuctx);
3502 
3503         /* Then walk through the lower prio flexible groups */
3504         if (is_active & EVENT_FLEXIBLE)
3505                 ctx_flexible_sched_in(ctx, cpuctx);
3506 }
3507 
3508 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3509                              enum event_type_t event_type,
3510                              struct task_struct *task)
3511 {
3512         struct perf_event_context *ctx = &cpuctx->ctx;
3513 
3514         ctx_sched_in(ctx, cpuctx, event_type, task);
3515 }
3516 
3517 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3518                                         struct task_struct *task)
3519 {
3520         struct perf_cpu_context *cpuctx;
3521 
3522         cpuctx = __get_cpu_context(ctx);
3523         if (cpuctx->task_ctx == ctx)
3524                 return;
3525 
3526         perf_ctx_lock(cpuctx, ctx);
3527         /*
3528          * We must check ctx->nr_events while holding ctx->lock, such
3529          * that we serialize against perf_install_in_context().
3530          */
3531         if (!ctx->nr_events)
3532                 goto unlock;
3533 
3534         perf_pmu_disable(ctx->pmu);
3535         /*
3536          * We want to keep the following priority order:
3537          * cpu pinned (that don't need to move), task pinned,
3538          * cpu flexible, task flexible.
3539          *
3540          * However, if task's ctx is not carrying any pinned
3541          * events, no need to flip the cpuctx's events around.
3542          */
3543         if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3544                 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3545         perf_event_sched_in(cpuctx, ctx, task);
3546         perf_pmu_enable(ctx->pmu);
3547 
3548 unlock:
3549         perf_ctx_unlock(cpuctx, ctx);
3550 }
3551 
3552 /*
3553  * Called from scheduler to add the events of the current task
3554  * with interrupts disabled.
3555  *
3556  * We restore the event value and then enable it.
3557  *
3558  * This does not protect us against NMI, but enable()
3559  * sets the enabled bit in the control field of event _before_
3560  * accessing the event control register. If a NMI hits, then it will
3561  * keep the event running.
3562  */
3563 void __perf_event_task_sched_in(struct task_struct *prev,
3564                                 struct task_struct *task)
3565 {
3566         struct perf_event_context *ctx;
3567         int ctxn;
3568 
3569         /*
3570          * If cgroup events exist on this CPU, then we need to check if we have
3571          * to switch in PMU state; cgroup event are system-wide mode only.
3572          *
3573          * Since cgroup events are CPU events, we must schedule these in before
3574          * we schedule in the task events.
3575          */
3576         if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3577                 perf_cgroup_sched_in(prev, task);
3578 
3579         for_each_task_context_nr(ctxn) {
3580                 ctx = task->perf_event_ctxp[ctxn];
3581                 if (likely(!ctx))
3582                         continue;
3583 
3584                 perf_event_context_sched_in(ctx, task);
3585         }
3586 
3587         if (atomic_read(&nr_switch_events))
3588                 perf_event_switch(task, prev, true);
3589 
3590         if (__this_cpu_read(perf_sched_cb_usages))
3591                 perf_pmu_sched_task(prev, task, true);
3592 }
3593 
3594 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3595 {
3596         u64 frequency = event->attr.sample_freq;
3597         u64 sec = NSEC_PER_SEC;
3598         u64 divisor, dividend;
3599 
3600         int count_fls, nsec_fls, frequency_fls, sec_fls;
3601 
3602         count_fls = fls64(count);
3603         nsec_fls = fls64(nsec);
3604         frequency_fls = fls64(frequency);
3605         sec_fls = 30;
3606 
3607         /*
3608          * We got @count in @nsec, with a target of sample_freq HZ
3609          * the target period becomes:
3610          *
3611          *             @count * 10^9
3612          * period = -------------------
3613          *          @nsec * sample_freq
3614          *
3615          */
3616 
3617         /*
3618          * Reduce accuracy by one bit such that @a and @b converge
3619          * to a similar magnitude.
3620          */
3621 #define REDUCE_FLS(a, b)                \
3622 do {                                    \
3623         if (a##_fls > b##_fls) {        \
3624                 a >>= 1;                \
3625                 a##_fls--;              \
3626         } else {                        \
3627                 b >>= 1;                \
3628                 b##_fls--;              \
3629         }                               \
3630 } while (0)
3631 
3632         /*
3633          * Reduce accuracy until either term fits in a u64, then proceed with
3634          * the other, so that finally we can do a u64/u64 division.
3635          */
3636         while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3637                 REDUCE_FLS(nsec, frequency);
3638                 REDUCE_FLS(sec, count);
3639         }
3640 
3641         if (count_fls + sec_fls > 64) {
3642                 divisor = nsec * frequency;
3643 
3644                 while (count_fls + sec_fls > 64) {
3645                         REDUCE_FLS(count, sec);
3646                         divisor >>= 1;
3647                 }
3648 
3649                 dividend = count * sec;
3650         } else {
3651                 dividend = count * sec;
3652 
3653                 while (nsec_fls + frequency_fls > 64) {
3654                         REDUCE_FLS(nsec, frequency);
3655                         dividend >>= 1;
3656                 }
3657 
3658                 divisor = nsec * frequency;
3659         }
3660 
3661         if (!divisor)
3662                 return dividend;
3663 
3664         return div64_u64(dividend, divisor);
3665 }
3666 
3667 static DEFINE_PER_CPU(int, perf_throttled_count);
3668 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3669 
3670 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3671 {
3672         struct hw_perf_event *hwc = &event->hw;
3673         s64 period, sample_period;
3674         s64 delta;
3675 
3676         period = perf_calculate_period(event, nsec, count);
3677 
3678         delta = (s64)(period - hwc->sample_period);
3679         delta = (delta + 7) / 8; /* low pass filter */
3680 
3681         sample_period = hwc->sample_period + delta;
3682 
3683         if (!sample_period)
3684                 sample_period = 1;
3685 
3686         hwc->sample_period = sample_period;
3687 
3688         if (local64_read(&hwc->period_left) > 8*sample_period) {
3689                 if (disable)
3690                         event->pmu->stop(event, PERF_EF_UPDATE);
3691 
3692                 local64_set(&hwc->period_left, 0);
3693 
3694                 if (disable)
3695                         event->pmu->start(event, PERF_EF_RELOAD);
3696         }
3697 }
3698 
3699 /*
3700  * combine freq adjustment with unthrottling to avoid two passes over the
3701  * events. At the same time, make sure, having freq events does not change
3702  * the rate of unthrottling as that would introduce bias.
3703  */
3704 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3705                                            int needs_unthr)
3706 {
3707         struct perf_event *event;
3708         struct hw_perf_event *hwc;
3709         u64 now, period = TICK_NSEC;
3710         s64 delta;
3711 
3712         /*
3713          * only need to iterate over all events iff:
3714          * - context have events in frequency mode (needs freq adjust)
3715          * - there are events to unthrottle on this cpu
3716          */
3717         if (!(ctx->nr_freq || needs_unthr))
3718                 return;
3719 
3720         raw_spin_lock(&ctx->lock);
3721         perf_pmu_disable(ctx->pmu);
3722 
3723         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3724                 if (event->state != PERF_EVENT_STATE_ACTIVE)
3725                         continue;
3726 
3727                 if (!event_filter_match(event))
3728                         continue;
3729 
3730                 perf_pmu_disable(event->pmu);
3731 
3732                 hwc = &event->hw;
3733 
3734                 if (hwc->interrupts == MAX_INTERRUPTS) {
3735                         hwc->interrupts = 0;
3736                         perf_log_throttle(event, 1);
3737                         event->pmu->start(event, 0);
3738                 }
3739 
3740                 if (!event->attr.freq || !event->attr.sample_freq)
3741                         goto next;
3742 
3743                 /*
3744                  * stop the event and update event->count
3745                  */
3746                 event->pmu->stop(event, PERF_EF_UPDATE);
3747 
3748                 now = local64_read(&event->count);
3749                 delta = now - hwc->freq_count_stamp;
3750                 hwc->freq_count_stamp = now;
3751 
3752                 /*
3753                  * restart the event
3754                  * reload only if value has changed
3755                  * we have stopped the event so tell that
3756                  * to perf_adjust_period() to avoid stopping it
3757                  * twice.
3758                  */
3759                 if (delta > 0)
3760                         perf_adjust_period(event, period, delta, false);
3761 
3762                 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3763         next:
3764                 perf_pmu_enable(event->pmu);
3765         }
3766 
3767         perf_pmu_enable(ctx->pmu);
3768         raw_spin_unlock(&ctx->lock);
3769 }
3770 
3771 /*
3772  * Move @event to the tail of the @ctx's elegible events.
3773  */
3774 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3775 {
3776         /*
3777          * Rotate the first entry last of non-pinned groups. Rotation might be
3778          * disabled by the inheritance code.
3779          */
3780         if (ctx->rotate_disable)
3781                 return;
3782 
3783         perf_event_groups_delete(&ctx->flexible_groups, event);
3784         perf_event_groups_insert(&ctx->flexible_groups, event);
3785 }
3786 
3787 /* pick an event from the flexible_groups to rotate */
3788 static inline struct perf_event *
3789 ctx_event_to_rotate(struct perf_event_context *ctx)
3790 {
3791         struct perf_event *event;
3792 
3793         /* pick the first active flexible event */
3794         event = list_first_entry_or_null(&ctx->flexible_active,
3795                                          struct perf_event, active_list);
3796 
3797         /* if no active flexible event, pick the first event */
3798         if (!event) {
3799                 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3800                                       typeof(*event), group_node);
3801         }
3802 
3803         return event;
3804 }
3805 
3806 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3807 {
3808         struct perf_event *cpu_event = NULL, *task_event = NULL;
3809         struct perf_event_context *task_ctx = NULL;
3810         int cpu_rotate, task_rotate;
3811 
3812         /*
3813          * Since we run this from IRQ context, nobody can install new
3814          * events, thus the event count values are stable.
3815          */
3816 
3817         cpu_rotate = cpuctx->ctx.rotate_necessary;
3818         task_ctx = cpuctx->task_ctx;
3819         task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3820 
3821         if (!(cpu_rotate || task_rotate))
3822                 return false;
3823 
3824         perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3825         perf_pmu_disable(cpuctx->ctx.pmu);
3826 
3827         if (task_rotate)
3828                 task_event = ctx_event_to_rotate(task_ctx);
3829         if (cpu_rotate)
3830                 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
3831 
3832         /*
3833          * As per the order given at ctx_resched() first 'pop' task flexible
3834          * and then, if needed CPU flexible.
3835          */
3836         if (task_event || (task_ctx && cpu_event))
3837                 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3838         if (cpu_event)
3839                 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3840 
3841         if (task_event)
3842                 rotate_ctx(task_ctx, task_event);
3843         if (cpu_event)
3844                 rotate_ctx(&cpuctx->ctx, cpu_event);
3845 
3846         perf_event_sched_in(cpuctx, task_ctx, current);
3847 
3848         perf_pmu_enable(cpuctx->ctx.pmu);
3849         perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3850 
3851         return true;
3852 }
3853 
3854 void perf_event_task_tick(void)
3855 {
3856         struct list_head *head = this_cpu_ptr(&active_ctx_list);
3857         struct perf_event_context *ctx, *tmp;
3858         int throttled;
3859 
3860         lockdep_assert_irqs_disabled();
3861 
3862         __this_cpu_inc(perf_throttled_seq);
3863         throttled = __this_cpu_xchg(perf_throttled_count, 0);
3864         tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3865 
3866         list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3867                 perf_adjust_freq_unthr_context(ctx, throttled);
3868 }
3869 
3870 static int event_enable_on_exec(struct perf_event *event,
3871                                 struct perf_event_context *ctx)
3872 {
3873         if (!event->attr.enable_on_exec)
3874                 return 0;
3875 
3876         event->attr.enable_on_exec = 0;
3877         if (event->state >= PERF_EVENT_STATE_INACTIVE)
3878                 return 0;
3879 
3880         perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3881 
3882         return 1;
3883 }
3884 
3885 /*
3886  * Enable all of a task's events that have been marked enable-on-exec.
3887  * This expects task == current.
3888  */
3889 static void perf_event_enable_on_exec(int ctxn)
3890 {
3891         struct perf_event_context *ctx, *clone_ctx = NULL;
3892         enum event_type_t event_type = 0;
3893         struct perf_cpu_context *cpuctx;
3894         struct perf_event *event;
3895         unsigned long flags;
3896         int enabled = 0;
3897 
3898         local_irq_save(flags);
3899         ctx = current->perf_event_ctxp[ctxn];
3900         if (!ctx || !ctx->nr_events)
3901                 goto out;
3902 
3903         cpuctx = __get_cpu_context(ctx);
3904         perf_ctx_lock(cpuctx, ctx);
3905         ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3906         list_for_each_entry(event, &ctx->event_list, event_entry) {
3907                 enabled |= event_enable_on_exec(event, ctx);
3908                 event_type |= get_event_type(event);
3909         }
3910 
3911         /*
3912          * Unclone and reschedule this context if we enabled any event.
3913          */
3914         if (enabled) {
3915                 clone_ctx = unclone_ctx(ctx);
3916                 ctx_resched(cpuctx, ctx, event_type);
3917         } else {
3918                 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3919         }
3920         perf_ctx_unlock(cpuctx, ctx);
3921 
3922 out:
3923         local_irq_restore(flags);
3924 
3925         if (clone_ctx)
3926                 put_ctx(clone_ctx);
3927 }
3928 
3929 struct perf_read_data {
3930         struct perf_event *event;
3931         bool group;
3932         int ret;
3933 };
3934 
3935 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3936 {
3937         u16 local_pkg, event_pkg;
3938 
3939         if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3940                 int local_cpu = smp_processor_id();
3941 
3942                 event_pkg = topology_physical_package_id(event_cpu);
3943                 local_pkg = topology_physical_package_id(local_cpu);
3944 
3945                 if (event_pkg == local_pkg)
3946                         return local_cpu;
3947         }
3948 
3949         return event_cpu;
3950 }
3951 
3952 /*
3953  * Cross CPU call to read the hardware event
3954  */
3955 static void __perf_event_read(void *info)
3956 {
3957         struct perf_read_data *data = info;
3958         struct perf_event *sub, *event = data->event;
3959         struct perf_event_context *ctx = event->ctx;
3960         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3961         struct pmu *pmu = event->pmu;
3962 
3963         /*
3964          * If this is a task context, we need to check whether it is
3965          * the current task context of this cpu.  If not it has been
3966          * scheduled out before the smp call arrived.  In that case
3967          * event->count would have been updated to a recent sample
3968          * when the event was scheduled out.
3969          */
3970         if (ctx->task && cpuctx->task_ctx != ctx)
3971                 return;
3972 
3973         raw_spin_lock(&ctx->lock);
3974         if (ctx->is_active & EVENT_TIME) {
3975                 update_context_time(ctx);
3976                 update_cgrp_time_from_event(event);
3977         }
3978 
3979         perf_event_update_time(event);
3980         if (data->group)
3981                 perf_event_update_sibling_time(event);
3982 
3983         if (event->state != PERF_EVENT_STATE_ACTIVE)
3984                 goto unlock;
3985 
3986         if (!data->group) {
3987                 pmu->read(event);
3988                 data->ret = 0;
3989                 goto unlock;
3990         }
3991 
3992         pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3993 
3994         pmu->read(event);
3995 
3996         for_each_sibling_event(sub, event) {
3997                 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3998                         /*
3999                          * Use sibling's PMU rather than @event's since
4000                          * sibling could be on different (eg: software) PMU.
4001                          */
4002                         sub->pmu->read(sub);
4003                 }
4004         }
4005 
4006         data->ret = pmu->commit_txn(pmu);
4007 
4008 unlock:
4009         raw_spin_unlock(&ctx->lock);
4010 }
4011 
4012 static inline u64 perf_event_count(struct perf_event *event)
4013 {
4014         return local64_read(&event->count) + atomic64_read(&event->child_count);
4015 }
4016 
4017 /*
4018  * NMI-safe method to read a local event, that is an event that
4019  * is:
4020  *   - either for the current task, or for this CPU
4021  *   - does not have inherit set, for inherited task events
4022  *     will not be local and we cannot read them atomically
4023  *   - must not have a pmu::count method
4024  */
4025 int perf_event_read_local(struct perf_event *event, u64 *value,
4026                           u64 *enabled, u64 *running)
4027 {
4028         unsigned long flags;
4029         int ret = 0;
4030 
4031         /*
4032          * Disabling interrupts avoids all counter scheduling (context
4033          * switches, timer based rotation and IPIs).
4034          */
4035         local_irq_save(flags);
4036 
4037         /*
4038          * It must not be an event with inherit set, we cannot read
4039          * all child counters from atomic context.
4040          */
4041         if (event->attr.inherit) {
4042                 ret = -EOPNOTSUPP;
4043                 goto out;
4044         }
4045 
4046         /* If this is a per-task event, it must be for current */
4047         if ((event->attach_state & PERF_ATTACH_TASK) &&
4048             event->hw.target != current) {
4049                 ret = -EINVAL;
4050                 goto out;
4051         }
4052 
4053         /* If this is a per-CPU event, it must be for this CPU */
4054         if (!(event->attach_state & PERF_ATTACH_TASK) &&
4055             event->cpu != smp_processor_id()) {
4056                 ret = -EINVAL;
4057                 goto out;
4058         }
4059 
4060         /* If this is a pinned event it must be running on this CPU */
4061         if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4062                 ret = -EBUSY;
4063                 goto out;
4064         }
4065 
4066         /*
4067          * If the event is currently on this CPU, its either a per-task event,
4068          * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4069          * oncpu == -1).
4070          */
4071         if (event->oncpu == smp_processor_id())
4072                 event->pmu->read(event);
4073 
4074         *value = local64_read(&event->count);
4075         if (enabled || running) {
4076                 u64 now = event->shadow_ctx_time + perf_clock();
4077                 u64 __enabled, __running;
4078 
4079                 __perf_update_times(event, now, &__enabled, &__running);
4080                 if (enabled)
4081                         *enabled = __enabled;
4082                 if (running)
4083                         *running = __running;
4084         }
4085 out:
4086         local_irq_restore(flags);
4087 
4088         return ret;
4089 }
4090 
4091 static int perf_event_read(struct perf_event *event, bool group)
4092 {
4093         enum perf_event_state state = READ_ONCE(event->state);
4094         int event_cpu, ret = 0;
4095 
4096         /*
4097          * If event is enabled and currently active on a CPU, update the
4098          * value in the event structure:
4099          */
4100 again:
4101         if (state == PERF_EVENT_STATE_ACTIVE) {
4102                 struct perf_read_data data;
4103 
4104                 /*
4105                  * Orders the ->state and ->oncpu loads such that if we see
4106                  * ACTIVE we must also see the right ->oncpu.
4107                  *
4108                  * Matches the smp_wmb() from event_sched_in().
4109                  */
4110                 smp_rmb();
4111 
4112                 event_cpu = READ_ONCE(event->oncpu);
4113                 if ((unsigned)event_cpu >= nr_cpu_ids)
4114                         return 0;
4115 
4116                 data = (struct perf_read_data){
4117                         .event = event,
4118                         .group = group,
4119                         .ret = 0,
4120                 };
4121 
4122                 preempt_disable();
4123                 event_cpu = __perf_event_read_cpu(event, event_cpu);
4124 
4125                 /*
4126                  * Purposely ignore the smp_call_function_single() return
4127                  * value.
4128                  *
4129                  * If event_cpu isn't a valid CPU it means the event got
4130                  * scheduled out and that will have updated the event count.
4131                  *
4132                  * Therefore, either way, we'll have an up-to-date event count
4133                  * after this.
4134                  */
4135                 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4136                 preempt_enable();
4137                 ret = data.ret;
4138 
4139         } else if (state == PERF_EVENT_STATE_INACTIVE) {
4140                 struct perf_event_context *ctx = event->ctx;
4141                 unsigned long flags;
4142 
4143                 raw_spin_lock_irqsave(&ctx->lock, flags);
4144                 state = event->state;
4145                 if (state != PERF_EVENT_STATE_INACTIVE) {
4146                         raw_spin_unlock_irqrestore(&ctx->lock, flags);
4147                         goto again;
4148                 }
4149 
4150                 /*
4151                  * May read while context is not active (e.g., thread is
4152                  * blocked), in that case we cannot update context time
4153                  */
4154                 if (ctx->is_active & EVENT_TIME) {
4155                         update_context_time(ctx);
4156                         update_cgrp_time_from_event(event);
4157                 }
4158 
4159                 perf_event_update_time(event);
4160                 if (group)
4161                         perf_event_update_sibling_time(event);
4162                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4163         }
4164 
4165         return ret;
4166 }
4167 
4168 /*
4169  * Initialize the perf_event context in a task_struct:
4170  */
4171 static void __perf_event_init_context(struct perf_event_context *ctx)
4172 {
4173         raw_spin_lock_init(&ctx->lock);
4174         mutex_init(&ctx->mutex);
4175         INIT_LIST_HEAD(&ctx->active_ctx_list);
4176         perf_event_groups_init(&ctx->pinned_groups);
4177         perf_event_groups_init(&ctx->flexible_groups);
4178         INIT_LIST_HEAD(&ctx->event_list);
4179         INIT_LIST_HEAD(&ctx->pinned_active);
4180         INIT_LIST_HEAD(&ctx->flexible_active);
4181         refcount_set(&ctx->refcount, 1);
4182 }
4183 
4184 static struct perf_event_context *
4185 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4186 {
4187         struct perf_event_context *ctx;
4188 
4189         ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4190         if (!ctx)
4191                 return NULL;
4192 
4193         __perf_event_init_context(ctx);
4194         if (task)
4195                 ctx->task = get_task_struct(task);
4196         ctx->pmu = pmu;
4197 
4198         return ctx;
4199 }
4200 
4201 static struct task_struct *
4202 find_lively_task_by_vpid(pid_t vpid)
4203 {
4204         struct task_struct *task;
4205 
4206         rcu_read_lock();
4207         if (!vpid)
4208                 task = current;
4209         else
4210                 task = find_task_by_vpid(vpid);
4211         if (task)
4212                 get_task_struct(task);
4213         rcu_read_unlock();
4214 
4215         if (!task)
4216                 return ERR_PTR(-ESRCH);
4217 
4218         return task;
4219 }
4220 
4221 /*
4222  * Returns a matching context with refcount and pincount.
4223  */
4224 static struct perf_event_context *
4225 find_get_context(struct pmu *pmu, struct task_struct *task,
4226                 struct perf_event *event)
4227 {
4228         struct perf_event_context *ctx, *clone_ctx = NULL;
4229         struct perf_cpu_context *cpuctx;
4230         void *task_ctx_data = NULL;
4231         unsigned long flags;
4232         int ctxn, err;
4233         int cpu = event->cpu;
4234 
4235         if (!task) {
4236                 /* Must be root to operate on a CPU event: */
4237                 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4238                         return ERR_PTR(-EACCES);
4239 
4240                 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4241                 ctx = &cpuctx->ctx;
4242                 get_ctx(ctx);
4243                 ++ctx->pin_count;
4244 
4245                 return ctx;
4246         }
4247 
4248         err = -EINVAL;
4249         ctxn = pmu->task_ctx_nr;
4250         if (ctxn < 0)
4251                 goto errout;
4252 
4253         if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4254                 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4255                 if (!task_ctx_data) {
4256                         err = -ENOMEM;
4257                         goto errout;
4258                 }
4259         }
4260 
4261 retry:
4262         ctx = perf_lock_task_context(task, ctxn, &flags);
4263         if (ctx) {
4264                 clone_ctx = unclone_ctx(ctx);
4265                 ++ctx->pin_count;
4266 
4267                 if (task_ctx_data && !ctx->task_ctx_data) {
4268                         ctx->task_ctx_data = task_ctx_data;
4269                         task_ctx_data = NULL;
4270                 }
4271                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4272 
4273                 if (clone_ctx)
4274                         put_ctx(clone_ctx);
4275         } else {
4276                 ctx = alloc_perf_context(pmu, task);
4277                 err = -ENOMEM;
4278                 if (!ctx)
4279                         goto errout;
4280 
4281                 if (task_ctx_data) {
4282                         ctx->task_ctx_data = task_ctx_data;
4283                         task_ctx_data = NULL;
4284                 }
4285 
4286                 err = 0;
4287                 mutex_lock(&task->perf_event_mutex);
4288                 /*
4289                  * If it has already passed perf_event_exit_task().
4290                  * we must see PF_EXITING, it takes this mutex too.
4291                  */
4292                 if (task->flags & PF_EXITING)
4293                         err = -ESRCH;
4294                 else if (task->perf_event_ctxp[ctxn])
4295                         err = -EAGAIN;
4296                 else {
4297                         get_ctx(ctx);
4298                         ++ctx->pin_count;
4299                         rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4300                 }
4301                 mutex_unlock(&task->perf_event_mutex);
4302 
4303                 if (unlikely(err)) {
4304                         put_ctx(ctx);
4305 
4306                         if (err == -EAGAIN)
4307                                 goto retry;
4308                         goto errout;
4309                 }
4310         }
4311 
4312         kfree(task_ctx_data);
4313         return ctx;
4314 
4315 errout:
4316         kfree(task_ctx_data);
4317         return ERR_PTR(err);
4318 }
4319 
4320 static void perf_event_free_filter(struct perf_event *event);
4321 static void perf_event_free_bpf_prog(struct perf_event *event);
4322 
4323 static void free_event_rcu(struct rcu_head *head)
4324 {
4325         struct perf_event *event;
4326 
4327         event = container_of(head, struct perf_event, rcu_head);
4328         if (event->ns)
4329                 put_pid_ns(event->ns);
4330         perf_event_free_filter(event);
4331         kfree(event);
4332 }
4333 
4334 static void ring_buffer_attach(struct perf_event *event,
4335                                struct ring_buffer *rb);
4336 
4337 static void detach_sb_event(struct perf_event *event)
4338 {
4339         struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4340 
4341         raw_spin_lock(&pel->lock);
4342         list_del_rcu(&event->sb_list);
4343         raw_spin_unlock(&pel->lock);
4344 }
4345 
4346 static bool is_sb_event(struct perf_event *event)
4347 {
4348         struct perf_event_attr *attr = &event->attr;
4349 
4350         if (event->parent)
4351                 return false;
4352 
4353         if (event->attach_state & PERF_ATTACH_TASK)
4354                 return false;
4355 
4356         if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4357             attr->comm || attr->comm_exec ||
4358             attr->task || attr->ksymbol ||
4359             attr->context_switch ||
4360             attr->bpf_event)
4361                 return true;
4362         return false;
4363 }
4364 
4365 static void unaccount_pmu_sb_event(struct perf_event *event)
4366 {
4367         if (is_sb_event(event))
4368                 detach_sb_event(event);
4369 }
4370 
4371 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4372 {
4373         if (event->parent)
4374                 return;
4375 
4376         if (is_cgroup_event(event))
4377                 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4378 }
4379 
4380 #ifdef CONFIG_NO_HZ_FULL
4381 static DEFINE_SPINLOCK(nr_freq_lock);
4382 #endif
4383 
4384 static void unaccount_freq_event_nohz(void)
4385 {
4386 #ifdef CONFIG_NO_HZ_FULL
4387         spin_lock(&nr_freq_lock);
4388         if (atomic_dec_and_test(&nr_freq_events))
4389                 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4390         spin_unlock(&nr_freq_lock);
4391 #endif
4392 }
4393 
4394 static void unaccount_freq_event(void)
4395 {
4396         if (tick_nohz_full_enabled())
4397                 unaccount_freq_event_nohz();
4398         else
4399                 atomic_dec(&nr_freq_events);
4400 }
4401 
4402 static void unaccount_event(struct perf_event *event)
4403 {
4404         bool dec = false;
4405 
4406         if (event->parent)
4407                 return;
4408 
4409         if (event->attach_state & PERF_ATTACH_TASK)
4410                 dec = true;
4411         if (event->attr.mmap || event->attr.mmap_data)
4412                 atomic_dec(&nr_mmap_events);
4413         if (event->attr.comm)
4414                 atomic_dec(&nr_comm_events);
4415         if (event->attr.namespaces)
4416                 atomic_dec(&nr_namespaces_events);
4417         if (event->attr.task)
4418                 atomic_dec(&nr_task_events);
4419         if (event->attr.freq)
4420                 unaccount_freq_event();
4421         if (event->attr.context_switch) {
4422                 dec = true;
4423                 atomic_dec(&nr_switch_events);
4424         }
4425         if (is_cgroup_event(event))
4426                 dec = true;
4427         if (has_branch_stack(event))
4428                 dec = true;
4429         if (event->attr.ksymbol)
4430                 atomic_dec(&nr_ksymbol_events);
4431         if (event->attr.bpf_event)
4432                 atomic_dec(&nr_bpf_events);
4433 
4434         if (dec) {
4435                 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4436                         schedule_delayed_work(&perf_sched_work, HZ);
4437         }
4438 
4439         unaccount_event_cpu(event, event->cpu);
4440 
4441         unaccount_pmu_sb_event(event);
4442 }
4443 
4444 static void perf_sched_delayed(struct work_struct *work)
4445 {
4446         mutex_lock(&perf_sched_mutex);
4447         if (atomic_dec_and_test(&perf_sched_count))
4448                 static_branch_disable(&perf_sched_events);
4449         mutex_unlock(&perf_sched_mutex);
4450 }
4451 
4452 /*
4453  * The following implement mutual exclusion of events on "exclusive" pmus
4454  * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4455  * at a time, so we disallow creating events that might conflict, namely:
4456  *
4457  *  1) cpu-wide events in the presence of per-task events,
4458  *  2) per-task events in the presence of cpu-wide events,
4459  *  3) two matching events on the same context.
4460  *
4461  * The former two cases are handled in the allocation path (perf_event_alloc(),
4462  * _free_event()), the latter -- before the first perf_install_in_context().
4463  */
4464 static int exclusive_event_init(struct perf_event *event)
4465 {
4466         struct pmu *pmu = event->pmu;
4467 
4468         if (!is_exclusive_pmu(pmu))
4469                 return 0;
4470 
4471         /*
4472          * Prevent co-existence of per-task and cpu-wide events on the
4473          * same exclusive pmu.
4474          *
4475          * Negative pmu::exclusive_cnt means there are cpu-wide
4476          * events on this "exclusive" pmu, positive means there are
4477          * per-task events.
4478          *
4479          * Since this is called in perf_event_alloc() path, event::ctx
4480          * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4481          * to mean "per-task event", because unlike other attach states it
4482          * never gets cleared.
4483          */
4484         if (event->attach_state & PERF_ATTACH_TASK) {
4485                 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4486                         return -EBUSY;
4487         } else {
4488                 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4489                         return -EBUSY;
4490         }
4491 
4492         return 0;
4493 }
4494 
4495 static void exclusive_event_destroy(struct perf_event *event)
4496 {
4497         struct pmu *pmu = event->pmu;
4498 
4499         if (!is_exclusive_pmu(pmu))
4500                 return;
4501 
4502         /* see comment in exclusive_event_init() */
4503         if (event->attach_state & PERF_ATTACH_TASK)
4504                 atomic_dec(&pmu->exclusive_cnt);
4505         else
4506                 atomic_inc(&pmu->exclusive_cnt);
4507 }
4508 
4509 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4510 {
4511         if ((e1->pmu == e2->pmu) &&
4512             (e1->cpu == e2->cpu ||
4513              e1->cpu == -1 ||
4514              e2->cpu == -1))
4515                 return true;
4516         return false;
4517 }
4518 
4519 static bool exclusive_event_installable(struct perf_event *event,
4520                                         struct perf_event_context *ctx)
4521 {
4522         struct perf_event *iter_event;
4523         struct pmu *pmu = event->pmu;
4524 
4525         lockdep_assert_held(&ctx->mutex);
4526 
4527         if (!is_exclusive_pmu(pmu))
4528                 return true;
4529 
4530         list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4531                 if (exclusive_event_match(iter_event, event))
4532                         return false;
4533         }
4534 
4535         return true;
4536 }
4537 
4538 static void perf_addr_filters_splice(struct perf_event *event,
4539                                        struct list_head *head);
4540 
4541 static void _free_event(struct perf_event *event)
4542 {
4543         irq_work_sync(&event->pending);
4544 
4545         unaccount_event(event);
4546 
4547         if (event->rb) {
4548                 /*
4549                  * Can happen when we close an event with re-directed output.
4550                  *
4551                  * Since we have a 0 refcount, perf_mmap_close() will skip
4552                  * over us; possibly making our ring_buffer_put() the last.
4553                  */
4554                 mutex_lock(&event->mmap_mutex);
4555                 ring_buffer_attach(event, NULL);
4556                 mutex_unlock(&event->mmap_mutex);
4557         }
4558 
4559         if (is_cgroup_event(event))
4560                 perf_detach_cgroup(event);
4561 
4562         if (!event->parent) {
4563                 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4564                         put_callchain_buffers();
4565         }
4566 
4567         perf_event_free_bpf_prog(event);
4568         perf_addr_filters_splice(event, NULL);
4569         kfree(event->addr_filter_ranges);
4570 
4571         if (event->destroy)
4572                 event->destroy(event);
4573 
4574         /*
4575          * Must be after ->destroy(), due to uprobe_perf_close() using
4576          * hw.target.
4577          */
4578         if (event->hw.target)
4579                 put_task_struct(event->hw.target);
4580 
4581         /*
4582          * perf_event_free_task() relies on put_ctx() being 'last', in particular
4583          * all task references must be cleaned up.
4584          */
4585         if (event->ctx)
4586                 put_ctx(event->ctx);
4587 
4588         exclusive_event_destroy(event);
4589         module_put(event->pmu->module);
4590 
4591         call_rcu(&event->rcu_head, free_event_rcu);
4592 }
4593 
4594 /*
4595  * Used to free events which have a known refcount of 1, such as in error paths
4596  * where the event isn't exposed yet and inherited events.
4597  */
4598 static void free_event(struct perf_event *event)
4599 {
4600         if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4601                                 "unexpected event refcount: %ld; ptr=%p\n",
4602                                 atomic_long_read(&event->refcount), event)) {
4603                 /* leak to avoid use-after-free */
4604                 return;
4605         }
4606 
4607         _free_event(event);
4608 }
4609 
4610 /*
4611  * Remove user event from the owner task.
4612  */
4613 static void perf_remove_from_owner(struct perf_event *event)
4614 {
4615         struct task_struct *owner;
4616 
4617         rcu_read_lock();
4618         /*
4619          * Matches the smp_store_release() in perf_event_exit_task(). If we
4620          * observe !owner it means the list deletion is complete and we can
4621          * indeed free this event, otherwise we need to serialize on
4622          * owner->perf_event_mutex.
4623          */
4624         owner = READ_ONCE(event->owner);
4625         if (owner) {
4626                 /*
4627                  * Since delayed_put_task_struct() also drops the last
4628                  * task reference we can safely take a new reference
4629                  * while holding the rcu_read_lock().
4630                  */
4631                 get_task_struct(owner);
4632         }
4633         rcu_read_unlock();
4634 
4635         if (owner) {
4636                 /*
4637                  * If we're here through perf_event_exit_task() we're already
4638                  * holding ctx->mutex which would be an inversion wrt. the
4639                  * normal lock order.
4640                  *
4641                  * However we can safely take this lock because its the child
4642                  * ctx->mutex.
4643                  */
4644                 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4645 
4646                 /*
4647                  * We have to re-check the event->owner field, if it is cleared
4648                  * we raced with perf_event_exit_task(), acquiring the mutex
4649                  * ensured they're done, and we can proceed with freeing the
4650                  * event.
4651                  */
4652                 if (event->owner) {
4653                         list_del_init(&event->owner_entry);
4654                         smp_store_release(&event->owner, NULL);
4655                 }
4656                 mutex_unlock(&owner->perf_event_mutex);
4657                 put_task_struct(owner);
4658         }
4659 }
4660 
4661 static void put_event(struct perf_event *event)
4662 {
4663         if (!atomic_long_dec_and_test(&event->refcount))
4664                 return;
4665 
4666         _free_event(event);
4667 }
4668 
4669 /*
4670  * Kill an event dead; while event:refcount will preserve the event
4671  * object, it will not preserve its functionality. Once the last 'user'
4672  * gives up the object, we'll destroy the thing.
4673  */
4674 int perf_event_release_kernel(struct perf_event *event)
4675 {
4676         struct perf_event_context *ctx = event->ctx;
4677         struct perf_event *child, *tmp;
4678         LIST_HEAD(free_list);
4679 
4680         /*
4681          * If we got here through err_file: fput(event_file); we will not have
4682          * attached to a context yet.
4683          */
4684         if (!ctx) {
4685                 WARN_ON_ONCE(event->attach_state &
4686                                 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4687                 goto no_ctx;
4688         }
4689 
4690         if (!is_kernel_event(event))
4691                 perf_remove_from_owner(event);
4692 
4693         ctx = perf_event_ctx_lock(event);
4694         WARN_ON_ONCE(ctx->parent_ctx);
4695         perf_remove_from_context(event, DETACH_GROUP);
4696 
4697         raw_spin_lock_irq(&ctx->lock);
4698         /*
4699          * Mark this event as STATE_DEAD, there is no external reference to it
4700          * anymore.
4701          *
4702          * Anybody acquiring event->child_mutex after the below loop _must_
4703          * also see this, most importantly inherit_event() which will avoid
4704          * placing more children on the list.
4705          *
4706          * Thus this guarantees that we will in fact observe and kill _ALL_
4707          * child events.
4708          */
4709         event->state = PERF_EVENT_STATE_DEAD;
4710         raw_spin_unlock_irq(&ctx->lock);
4711 
4712         perf_event_ctx_unlock(event, ctx);
4713 
4714 again:
4715         mutex_lock(&event->child_mutex);
4716         list_for_each_entry(child, &event->child_list, child_list) {
4717 
4718                 /*
4719                  * Cannot change, child events are not migrated, see the
4720                  * comment with perf_event_ctx_lock_nested().
4721                  */
4722                 ctx = READ_ONCE(child->ctx);
4723                 /*
4724                  * Since child_mutex nests inside ctx::mutex, we must jump
4725                  * through hoops. We start by grabbing a reference on the ctx.
4726                  *
4727                  * Since the event cannot get freed while we hold the
4728                  * child_mutex, the context must also exist and have a !0
4729                  * reference count.
4730                  */
4731                 get_ctx(ctx);
4732 
4733                 /*
4734                  * Now that we have a ctx ref, we can drop child_mutex, and
4735                  * acquire ctx::mutex without fear of it going away. Then we
4736                  * can re-acquire child_mutex.
4737                  */
4738                 mutex_unlock(&event->child_mutex);
4739                 mutex_lock(&ctx->mutex);
4740                 mutex_lock(&event->child_mutex);
4741 
4742                 /*
4743                  * Now that we hold ctx::mutex and child_mutex, revalidate our
4744                  * state, if child is still the first entry, it didn't get freed
4745                  * and we can continue doing so.
4746                  */
4747                 tmp = list_first_entry_or_null(&event->child_list,
4748                                                struct perf_event, child_list);
4749                 if (tmp == child) {
4750                         perf_remove_from_context(child, DETACH_GROUP);
4751                         list_move(&child->child_list, &free_list);
4752                         /*
4753                          * This matches the refcount bump in inherit_event();
4754                          * this can't be the last reference.
4755                          */
4756                         put_event(event);
4757                 }
4758 
4759                 mutex_unlock(&event->child_mutex);
4760                 mutex_unlock(&ctx->mutex);
4761                 put_ctx(ctx);
4762                 goto again;
4763         }
4764         mutex_unlock(&event->child_mutex);
4765 
4766         list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4767                 void *var = &child->ctx->refcount;
4768 
4769                 list_del(&child->child_list);
4770                 free_event(child);
4771 
4772                 /*
4773                  * Wake any perf_event_free_task() waiting for this event to be
4774                  * freed.
4775                  */
4776                 smp_mb(); /* pairs with wait_var_event() */
4777                 wake_up_var(var);
4778         }
4779 
4780 no_ctx:
4781         put_event(event); /* Must be the 'last' reference */
4782         return 0;
4783 }
4784 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4785 
4786 /*
4787  * Called when the last reference to the file is gone.
4788  */
4789 static int perf_release(struct inode *inode, struct file *file)
4790 {
4791         perf_event_release_kernel(file->private_data);
4792         return 0;
4793 }
4794 
4795 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4796 {
4797         struct perf_event *child;
4798         u64 total = 0;
4799 
4800         *enabled = 0;
4801         *running = 0;
4802 
4803         mutex_lock(&event->child_mutex);
4804 
4805         (void)perf_event_read(event, false);
4806         total += perf_event_count(event);
4807 
4808         *enabled += event->total_time_enabled +
4809                         atomic64_read(&event->child_total_time_enabled);
4810         *running += event->total_time_running +
4811                         atomic64_read(&event->child_total_time_running);
4812 
4813         list_for_each_entry(child, &event->child_list, child_list) {
4814                 (void)perf_event_read(child, false);
4815                 total += perf_event_count(child);
4816                 *enabled += child->total_time_enabled;
4817                 *running += child->total_time_running;
4818         }
4819         mutex_unlock(&event->child_mutex);
4820 
4821         return total;
4822 }
4823 
4824 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4825 {
4826         struct perf_event_context *ctx;
4827         u64 count;
4828 
4829         ctx = perf_event_ctx_lock(event);
4830         count = __perf_event_read_value(event, enabled, running);
4831         perf_event_ctx_unlock(event, ctx);
4832 
4833         return count;
4834 }
4835 EXPORT_SYMBOL_GPL(perf_event_read_value);
4836 
4837 static int __perf_read_group_add(struct perf_event *leader,
4838                                         u64 read_format, u64 *values)
4839 {
4840         struct perf_event_context *ctx = leader->ctx;
4841         struct perf_event *sub;
4842         unsigned long flags;
4843         int n = 1; /* skip @nr */
4844         int ret;
4845 
4846         ret = perf_event_read(leader, true);
4847         if (ret)
4848                 return ret;
4849 
4850         raw_spin_lock_irqsave(&ctx->lock, flags);
4851 
4852         /*
4853          * Since we co-schedule groups, {enabled,running} times of siblings
4854          * will be identical to those of the leader, so we only publish one
4855          * set.
4856          */
4857         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4858                 values[n++] += leader->total_time_enabled +
4859                         atomic64_read(&leader->child_total_time_enabled);
4860         }
4861 
4862         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4863                 values[n++] += leader->total_time_running +
4864                         atomic64_read(&leader->child_total_time_running);
4865         }
4866 
4867         /*
4868          * Write {count,id} tuples for every sibling.
4869          */
4870         values[n++] += perf_event_count(leader);
4871         if (read_format & PERF_FORMAT_ID)
4872                 values[n++] = primary_event_id(leader);
4873 
4874         for_each_sibling_event(sub, leader) {
4875                 values[n++] += perf_event_count(sub);
4876                 if (read_format & PERF_FORMAT_ID)
4877                         values[n++] = primary_event_id(sub);
4878         }
4879 
4880         raw_spin_unlock_irqrestore(&ctx->lock, flags);
4881         return 0;
4882 }
4883 
4884 static int perf_read_group(struct perf_event *event,
4885                                    u64 read_format, char __user *buf)
4886 {
4887         struct perf_event *leader = event->group_leader, *child;
4888         struct perf_event_context *ctx = leader->ctx;
4889         int ret;
4890         u64 *values;
4891 
4892         lockdep_assert_held(&ctx->mutex);
4893 
4894         values = kzalloc(event->read_size, GFP_KERNEL);
4895         if (!values)
4896                 return -ENOMEM;
4897 
4898         values[0] = 1 + leader->nr_siblings;
4899 
4900         /*
4901          * By locking the child_mutex of the leader we effectively
4902          * lock the child list of all siblings.. XXX explain how.
4903          */
4904         mutex_lock(&leader->child_mutex);
4905 
4906         ret = __perf_read_group_add(leader, read_format, values);
4907         if (ret)
4908                 goto unlock;
4909 
4910         list_for_each_entry(child, &leader->child_list, child_list) {
4911                 ret = __perf_read_group_add(child, read_format, values);
4912                 if (ret)
4913                         goto unlock;
4914         }
4915 
4916         mutex_unlock(&leader->child_mutex);
4917 
4918         ret = event->read_size;
4919         if (copy_to_user(buf, values, event->read_size))
4920                 ret = -EFAULT;
4921         goto out;
4922 
4923 unlock:
4924         mutex_unlock(&leader->child_mutex);
4925 out:
4926         kfree(values);
4927         return ret;
4928 }
4929 
4930 static int perf_read_one(struct perf_event *event,
4931                                  u64 read_format, char __user *buf)
4932 {
4933         u64 enabled, running;
4934         u64 values[4];
4935         int n = 0;
4936 
4937         values[n++] = __perf_event_read_value(event, &enabled, &running);
4938         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4939                 values[n++] = enabled;
4940         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4941                 values[n++] = running;
4942         if (read_format & PERF_FORMAT_ID)
4943                 values[n++] = primary_event_id(event);
4944 
4945         if (copy_to_user(buf, values, n * sizeof(u64)))
4946                 return -EFAULT;
4947 
4948         return n * sizeof(u64);
4949 }
4950 
4951 static bool is_event_hup(struct perf_event *event)
4952 {
4953         bool no_children;
4954 
4955         if (event->state > PERF_EVENT_STATE_EXIT)
4956                 return false;
4957 
4958         mutex_lock(&event->child_mutex);
4959         no_children = list_empty(&event->child_list);
4960         mutex_unlock(&event->child_mutex);
4961         return no_children;
4962 }
4963 
4964 /*
4965  * Read the performance event - simple non blocking version for now
4966  */
4967 static ssize_t
4968 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4969 {
4970         u64 read_format = event->attr.read_format;
4971         int ret;
4972 
4973         /*
4974          * Return end-of-file for a read on an event that is in
4975          * error state (i.e. because it was pinned but it couldn't be
4976          * scheduled on to the CPU at some point).
4977          */
4978         if (event->state == PERF_EVENT_STATE_ERROR)
4979                 return 0;
4980 
4981         if (count < event->read_size)
4982                 return -ENOSPC;
4983 
4984         WARN_ON_ONCE(event->ctx->parent_ctx);
4985         if (read_format & PERF_FORMAT_GROUP)
4986                 ret = perf_read_group(event, read_format, buf);
4987         else
4988                 ret = perf_read_one(event, read_format, buf);
4989 
4990         return ret;
4991 }
4992 
4993 static ssize_t
4994 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4995 {
4996         struct perf_event *event = file->private_data;
4997         struct perf_event_context *ctx;
4998         int ret;
4999 
5000         ctx = perf_event_ctx_lock(event);
5001         ret = __perf_read(event, buf, count);
5002         perf_event_ctx_unlock(event, ctx);
5003 
5004         return ret;
5005 }
5006 
5007 static __poll_t perf_poll(struct file *file, poll_table *wait)
5008 {
5009         struct perf_event *event = file->private_data;
5010         struct ring_buffer *rb;
5011         __poll_t events = EPOLLHUP;
5012 
5013         poll_wait(file, &event->waitq, wait);
5014 
5015         if (is_event_hup(event))
5016                 return events;
5017 
5018         /*
5019          * Pin the event->rb by taking event->mmap_mutex; otherwise
5020          * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5021          */
5022         mutex_lock(&event->mmap_mutex);
5023         rb = event->rb;
5024         if (rb)
5025                 events = atomic_xchg(&rb->poll, 0);
5026         mutex_unlock(&event->mmap_mutex);
5027         return events;
5028 }
5029 
5030 static void _perf_event_reset(struct perf_event *event)
5031 {
5032         (void)perf_event_read(event, false);
5033         local64_set(&event->count, 0);
5034         perf_event_update_userpage(event);
5035 }
5036 
5037 /*
5038  * Holding the top-level event's child_mutex means that any
5039  * descendant process that has inherited this event will block
5040  * in perf_event_exit_event() if it goes to exit, thus satisfying the
5041  * task existence requirements of perf_event_enable/disable.
5042  */
5043 static void perf_event_for_each_child(struct perf_event *event,
5044                                         void (*func)(struct perf_event *))
5045 {
5046         struct perf_event *child;
5047 
5048         WARN_ON_ONCE(event->ctx->parent_ctx);
5049 
5050         mutex_lock(&event->child_mutex);
5051         func(event);
5052         list_for_each_entry(child, &event->child_list, child_list)
5053                 func(child);
5054         mutex_unlock(&event->child_mutex);
5055 }
5056 
5057 static void perf_event_for_each(struct perf_event *event,
5058                                   void (*func)(struct perf_event *))
5059 {
5060         struct perf_event_context *ctx = event->ctx;
5061         struct perf_event *sibling;
5062 
5063         lockdep_assert_held(&ctx->mutex);
5064 
5065         event = event->group_leader;
5066 
5067         perf_event_for_each_child(event, func);
5068         for_each_sibling_event(sibling, event)
5069                 perf_event_for_each_child(sibling, func);
5070 }
5071 
5072 static void __perf_event_period(struct perf_event *event,
5073                                 struct perf_cpu_context *cpuctx,
5074                                 struct perf_event_context *ctx,
5075                                 void *info)
5076 {
5077         u64 value = *((u64 *)info);
5078         bool active;
5079 
5080         if (event->attr.freq) {
5081                 event->attr.sample_freq = value;
5082         } else {
5083                 event->attr.sample_period = value;
5084                 event->hw.sample_period = value;
5085         }
5086 
5087         active = (event->state == PERF_EVENT_STATE_ACTIVE);
5088         if (active) {
5089                 perf_pmu_disable(ctx->pmu);
5090                 /*
5091                  * We could be throttled; unthrottle now to avoid the tick
5092                  * trying to unthrottle while we already re-started the event.
5093                  */
5094                 if (event->hw.interrupts == MAX_INTERRUPTS) {
5095                         event->hw.interrupts = 0;
5096                         perf_log_throttle(event, 1);
5097                 }
5098                 event->pmu->stop(event, PERF_EF_UPDATE);
5099         }
5100 
5101         local64_set(&event->hw.period_left, 0);
5102 
5103         if (active) {
5104                 event->pmu->start(event, PERF_EF_RELOAD);
5105                 perf_pmu_enable(ctx->pmu);
5106         }
5107 }
5108 
5109 static int perf_event_check_period(struct perf_event *event, u64 value)
5110 {
5111         return event->pmu->check_period(event, value);
5112 }
5113 
5114 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5115 {
5116         u64 value;
5117 
5118         if (!is_sampling_event(event))
5119                 return -EINVAL;
5120 
5121         if (copy_from_user(&value, arg, sizeof(value)))
5122                 return -EFAULT;
5123 
5124         if (!value)
5125                 return -EINVAL;
5126 
5127         if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5128                 return -EINVAL;
5129 
5130         if (perf_event_check_period(event, value))
5131                 return -EINVAL;
5132 
5133         if (!event->attr.freq && (value & (1ULL << 63)))
5134                 return -EINVAL;
5135 
5136         event_function_call(event, __perf_event_period, &value);
5137 
5138         return 0;
5139 }
5140 
5141 static const struct file_operations perf_fops;
5142 
5143 static inline int perf_fget_light(int fd, struct fd *p)
5144 {
5145         struct fd f = fdget(fd);
5146         if (!f.file)
5147                 return -EBADF;
5148 
5149         if (f.file->f_op != &perf_fops) {
5150                 fdput(f);
5151                 return -EBADF;
5152         }
5153         *p = f;
5154         return 0;
5155 }
5156 
5157 static int perf_event_set_output(struct perf_event *event,
5158                                  struct perf_event *output_event);
5159 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5160 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5161 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5162                           struct perf_event_attr *attr);
5163 
5164 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5165 {
5166         void (*func)(struct perf_event *);
5167         u32 flags = arg;
5168 
5169         switch (cmd) {
5170         case PERF_EVENT_IOC_ENABLE:
5171                 func = _perf_event_enable;
5172                 break;
5173         case PERF_EVENT_IOC_DISABLE:
5174                 func = _perf_event_disable;
5175                 break;
5176         case PERF_EVENT_IOC_RESET:
5177                 func = _perf_event_reset;
5178                 break;
5179 
5180         case PERF_EVENT_IOC_REFRESH:
5181                 return _perf_event_refresh(event, arg);
5182 
5183         case PERF_EVENT_IOC_PERIOD:
5184                 return perf_event_period(event, (u64 __user *)arg);
5185 
5186         case PERF_EVENT_IOC_ID:
5187         {
5188                 u64 id = primary_event_id(event);
5189 
5190                 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5191                         return -EFAULT;
5192                 return 0;
5193         }
5194 
5195         case PERF_EVENT_IOC_SET_OUTPUT:
5196         {
5197                 int ret;
5198                 if (arg != -1) {
5199                         struct perf_event *output_event;
5200                         struct fd output;
5201                         ret = perf_fget_light(arg, &output);
5202                         if (ret)
5203                                 return ret;
5204                         output_event = output.file->private_data;
5205                         ret = perf_event_set_output(event, output_event);
5206                         fdput(output);
5207                 } else {
5208                         ret = perf_event_set_output(event, NULL);
5209                 }
5210                 return ret;
5211         }
5212 
5213         case PERF_EVENT_IOC_SET_FILTER:
5214                 return perf_event_set_filter(event, (void __user *)arg);
5215 
5216         case PERF_EVENT_IOC_SET_BPF:
5217                 return perf_event_set_bpf_prog(event, arg);
5218 
5219         case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5220                 struct ring_buffer *rb;
5221 
5222                 rcu_read_lock();
5223                 rb = rcu_dereference(event->rb);
5224                 if (!rb || !rb->nr_pages) {
5225                         rcu_read_unlock();
5226                         return -EINVAL;
5227                 }
5228                 rb_toggle_paused(rb, !!arg);
5229                 rcu_read_unlock();
5230                 return 0;
5231         }
5232 
5233         case PERF_EVENT_IOC_QUERY_BPF:
5234                 return perf_event_query_prog_array(event, (void __user *)arg);
5235 
5236         case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5237                 struct perf_event_attr new_attr;
5238                 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5239                                          &new_attr);
5240 
5241                 if (err)
5242                         return err;
5243 
5244                 return perf_event_modify_attr(event,  &new_attr);
5245         }
5246         default:
5247                 return -ENOTTY;
5248         }
5249 
5250         if (flags & PERF_IOC_FLAG_GROUP)
5251                 perf_event_for_each(event, func);
5252         else
5253                 perf_event_for_each_child(event, func);
5254 
5255         return 0;
5256 }
5257 
5258 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5259 {
5260         struct perf_event *event = file->private_data;
5261         struct perf_event_context *ctx;
5262         long ret;
5263 
5264         ctx = perf_event_ctx_lock(event);
5265         ret = _perf_ioctl(event, cmd, arg);
5266         perf_event_ctx_unlock(event, ctx);
5267 
5268         return ret;
5269 }
5270 
5271 #ifdef CONFIG_COMPAT
5272 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5273                                 unsigned long arg)
5274 {
5275         switch (_IOC_NR(cmd)) {
5276         case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5277         case _IOC_NR(PERF_EVENT_IOC_ID):
5278         case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5279         case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5280                 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5281                 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5282                         cmd &= ~IOCSIZE_MASK;
5283                         cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5284                 }
5285                 break;
5286         }
5287         return perf_ioctl(file, cmd, arg);
5288 }
5289 #else
5290 # define perf_compat_ioctl NULL
5291 #endif
5292 
5293 int perf_event_task_enable(void)
5294 {
5295         struct perf_event_context *ctx;
5296         struct perf_event *event;
5297 
5298         mutex_lock(&current->perf_event_mutex);
5299         list_for_each_entry(event, &current->perf_event_list, owner_entry) {
5300                 ctx = perf_event_ctx_lock(event);
5301                 perf_event_for_each_child(event, _perf_event_enable);
5302                 perf_event_ctx_unlock(event, ctx);
5303         }
5304         mutex_unlock(&current->perf_event_mutex);
5305 
5306         return 0;
5307 }
5308 
5309 int perf_event_task_disable(void)
5310 {
5311         struct perf_event_context *ctx;
5312         struct perf_event *event;
5313 
5314         mutex_lock(&current->perf_event_mutex);
5315         list_for_each_entry(event, &current->perf_event_list, owner_entry) {
5316                 ctx = perf_event_ctx_lock(event);
5317                 perf_event_for_each_child(event, _perf_event_disable);
5318                 perf_event_ctx_unlock(event, ctx);
5319         }
5320         mutex_unlock(&current->perf_event_mutex);
5321 
5322         return 0;
5323 }
5324 
5325 static int perf_event_index(struct perf_event *event)
5326 {
5327         if (event->hw.state & PERF_HES_STOPPED)
5328                 return 0;
5329 
5330         if (event->state != PERF_EVENT_STATE_ACTIVE)
5331                 return 0;
5332 
5333         return event->pmu->event_idx(event);
5334 }
5335 
5336 static void calc_timer_values(struct perf_event *event,
5337                                 u64 *now,
5338                                 u64 *enabled,
5339                                 u64 *running)
5340 {
5341         u64 ctx_time;
5342 
5343         *now = perf_clock();
5344         ctx_time = event->shadow_ctx_time + *now;
5345         __perf_update_times(event, ctx_time, enabled, running);
5346 }
5347 
5348 static void perf_event_init_userpage(struct perf_event *event)
5349 {
5350         struct perf_event_mmap_page *userpg;
5351         struct ring_buffer *rb;
5352 
5353         rcu_read_lock();
5354         rb = rcu_dereference(event->rb);
5355         if (!rb)
5356                 goto unlock;
5357 
5358         userpg = rb->user_page;
5359 
5360         /* Allow new userspace to detect that bit 0 is deprecated */
5361         userpg->cap_bit0_is_deprecated = 1;
5362         userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5363         userpg->data_offset = PAGE_SIZE;
5364         userpg->data_size = perf_data_size(rb);
5365 
5366 unlock:
5367         rcu_read_unlock();
5368 }
5369 
5370 void __weak arch_perf_update_userpage(
5371         struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5372 {
5373 }
5374 
5375 /*
5376  * Callers need to ensure there can be no nesting of this function, otherwise
5377  * the seqlock logic goes bad. We can not serialize this because the arch
5378  * code calls this from NMI context.
5379  */
5380 void perf_event_update_userpage(struct perf_event *event)
5381 {
5382         struct perf_event_mmap_page *userpg;
5383         struct ring_buffer *rb;
5384         u64 enabled, running, now;
5385 
5386         rcu_read_lock();
5387         rb = rcu_dereference(event->rb);
5388         if (!rb)
5389                 goto unlock;
5390 
5391         /*
5392          * compute total_time_enabled, total_time_running
5393          * based on snapshot values taken when the event
5394          * was last scheduled in.
5395          *
5396          * we cannot simply called update_context_time()
5397          * because of locking issue as we can be called in
5398          * NMI context
5399          */
5400         calc_timer_values(event, &now, &enabled, &running);
5401 
5402         userpg = rb->user_page;
5403         /*
5404          * Disable preemption to guarantee consistent time stamps are stored to
5405          * the user page.
5406          */
5407         preempt_disable();
5408         ++userpg->lock;
5409         barrier();
5410         userpg->index = perf_event_index(event);
5411         userpg->offset = perf_event_count(event);
5412         if (userpg->index)
5413                 userpg->offset -= local64_read(&event->hw.prev_count);
5414 
5415         userpg->time_enabled = enabled +
5416                         atomic64_read(&event->child_total_time_enabled);
5417 
5418         userpg->time_running = running +
5419                         atomic64_read(&event->child_total_time_running);
5420 
5421         arch_perf_update_userpage(event, userpg, now);
5422 
5423         barrier();
5424         ++userpg->lock;
5425         preempt_enable();
5426 unlock:
5427         rcu_read_unlock();
5428 }
5429 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5430 
5431 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5432 {
5433         struct perf_event *event = vmf->vma->vm_file->private_data;
5434         struct ring_buffer *rb;
5435         vm_fault_t ret = VM_FAULT_SIGBUS;
5436 
5437         if (vmf->flags & FAULT_FLAG_MKWRITE) {
5438                 if (vmf->pgoff == 0)
5439                         ret = 0;
5440                 return ret;
5441         }
5442 
5443         rcu_read_lock();
5444         rb = rcu_dereference(event->rb);
5445         if (!rb)
5446                 goto unlock;
5447 
5448         if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5449                 goto unlock;
5450 
5451         vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5452         if (!vmf->page)
5453                 goto unlock;
5454 
5455         get_page(vmf->page);
5456         vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5457         vmf->page->index   = vmf->pgoff;
5458 
5459         ret = 0;
5460 unlock:
5461         rcu_read_unlock();
5462 
5463         return ret;
5464 }
5465 
5466 static void ring_buffer_attach(struct perf_event *event,
5467                                struct ring_buffer *rb)
5468 {
5469         struct ring_buffer *old_rb = NULL;
5470         unsigned long flags;
5471 
5472         if (event->rb) {
5473                 /*
5474                  * Should be impossible, we set this when removing
5475                  * event->rb_entry and wait/clear when adding event->rb_entry.
5476                  */
5477                 WARN_ON_ONCE(event->rcu_pending);
5478 
5479                 old_rb = event->rb;
5480                 spin_lock_irqsave(&old_rb->event_lock, flags);
5481                 list_del_rcu(&event->rb_entry);
5482                 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5483 
5484                 event->rcu_batches = get_state_synchronize_rcu();
5485                 event->rcu_pending = 1;
5486         }
5487 
5488         if (rb) {
5489                 if (event->rcu_pending) {
5490                         cond_synchronize_rcu(event->rcu_batches);
5491                         event->rcu_pending = 0;
5492                 }
5493 
5494                 spin_lock_irqsave(&rb->event_lock, flags);
5495                 list_add_rcu(&event->rb_entry, &rb->event_list);
5496                 spin_unlock_irqrestore(&rb->event_lock, flags);
5497         }
5498 
5499         /*
5500          * Avoid racing with perf_mmap_close(AUX): stop the event
5501          * before swizzling the event::rb pointer; if it's getting
5502          * unmapped, its aux_mmap_count will be 0 and it won't
5503          * restart. See the comment in __perf_pmu_output_stop().
5504          *
5505          * Data will inevitably be lost when set_output is done in
5506          * mid-air, but then again, whoever does it like this is
5507          * not in for the data anyway.
5508          */
5509         if (has_aux(event))
5510                 perf_event_stop(event, 0);
5511 
5512         rcu_assign_pointer(event->rb, rb);
5513 
5514         if (old_rb) {
5515                 ring_buffer_put(old_rb);
5516                 /*
5517                  * Since we detached before setting the new rb, so that we
5518                  * could attach the new rb, we could have missed a wakeup.
5519                  * Provide it now.
5520                  */
5521                 wake_up_all(&event->waitq);
5522         }
5523 }
5524 
5525 static void ring_buffer_wakeup(struct perf_event *event)
5526 {
5527         struct ring_buffer *rb;
5528 
5529         rcu_read_lock();
5530         rb = rcu_dereference(event->rb);
5531         if (rb) {
5532                 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5533                         wake_up_all(&event->waitq);
5534         }
5535         rcu_read_unlock();
5536 }
5537 
5538 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5539 {
5540         struct ring_buffer *rb;
5541 
5542         rcu_read_lock();
5543         rb = rcu_dereference(event->rb);
5544         if (rb) {
5545                 if (!refcount_inc_not_zero(&rb->refcount))
5546                         rb = NULL;
5547         }
5548         rcu_read_unlock();
5549 
5550         return rb;
5551 }
5552 
5553 void ring_buffer_put(struct ring_buffer *rb)
5554 {
5555         if (!refcount_dec_and_test(&rb->refcount))
5556                 return;
5557 
5558         WARN_ON_ONCE(!list_empty(&rb->event_list));
5559 
5560         call_rcu(&rb->rcu_head, rb_free_rcu);
5561 }
5562 
5563 static void perf_mmap_open(struct vm_area_struct *vma)
5564 {
5565         struct perf_event *event = vma->vm_file->private_data;
5566 
5567         atomic_inc(&event->mmap_count);
5568         atomic_inc(&event->rb->mmap_count);
5569 
5570         if (vma->vm_pgoff)
5571                 atomic_inc(&event->rb->aux_mmap_count);
5572 
5573         if (event->pmu->event_mapped)
5574                 event->pmu->event_mapped(event, vma->vm_mm);
5575 }
5576 
5577 static void perf_pmu_output_stop(struct perf_event *event);
5578 
5579 /*
5580  * A buffer can be mmap()ed multiple times; either directly through the same
5581  * event, or through other events by use of perf_event_set_output().
5582  *
5583  * In order to undo the VM accounting done by perf_mmap() we need to destroy
5584  * the buffer here, where we still have a VM context. This means we need
5585  * to detach all events redirecting to us.
5586  */
5587 static void perf_mmap_close(struct vm_area_struct *vma)
5588 {
5589         struct perf_event *event = vma->vm_file->private_data;
5590 
5591         struct ring_buffer *rb = ring_buffer_get(event);
5592         struct user_struct *mmap_user = rb->mmap_user;
5593         int mmap_locked = rb->mmap_locked;
5594         unsigned long size = perf_data_size(rb);
5595 
5596         if (event->pmu->event_unmapped)
5597                 event->pmu->event_unmapped(event, vma->vm_mm);
5598 
5599         /*
5600          * rb->aux_mmap_count will always drop before rb->mmap_count and
5601          * event->mmap_count, so it is ok to use event->mmap_mutex to
5602          * serialize with perf_mmap here.
5603          */
5604         if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5605             atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5606                 /*
5607                  * Stop all AUX events that are writing to this buffer,
5608                  * so that we can free its AUX pages and corresponding PMU
5609                  * data. Note that after rb::aux_mmap_count dropped to zero,
5610                  * they won't start any more (see perf_aux_output_begin()).
5611                  */
5612                 perf_pmu_output_stop(event);
5613 
5614                 /* now it's safe to free the pages */
5615                 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
5616                 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5617 
5618                 /* this has to be the last one */
5619                 rb_free_aux(rb);
5620                 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5621 
5622                 mutex_unlock(&event->mmap_mutex);
5623         }
5624 
5625         atomic_dec(&rb->mmap_count);
5626 
5627         if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5628                 goto out_put;
5629 
5630         ring_buffer_attach(event, NULL);
5631         mutex_unlock(&event->mmap_mutex);
5632 
5633         /* If there's still other mmap()s of this buffer, we're done. */
5634         if (atomic_read(&rb->mmap_count))
5635                 goto out_put;
5636 
5637         /*
5638          * No other mmap()s, detach from all other events that might redirect
5639          * into the now unreachable buffer. Somewhat complicated by the
5640          * fact that rb::event_lock otherwise nests inside mmap_mutex.
5641          */
5642 again:
5643         rcu_read_lock();
5644         list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5645                 if (!atomic_long_inc_not_zero(&event->refcount)) {
5646                         /*
5647                          * This event is en-route to free_event() which will
5648                          * detach it and remove it from the list.
5649                          */
5650                         continue;
5651                 }
5652                 rcu_read_unlock();
5653 
5654                 mutex_lock(&event->mmap_mutex);
5655                 /*
5656                  * Check we didn't race with perf_event_set_output() which can
5657                  * swizzle the rb from under us while we were waiting to
5658                  * acquire mmap_mutex.
5659                  *
5660                  * If we find a different rb; ignore this event, a next
5661                  * iteration will no longer find it on the list. We have to
5662                  * still restart the iteration to make sure we're not now
5663                  * iterating the wrong list.
5664                  */
5665                 if (event->rb == rb)
5666                         ring_buffer_attach(event, NULL);
5667 
5668                 mutex_unlock(&event->mmap_mutex);
5669                 put_event(event);
5670 
5671                 /*
5672                  * Restart the iteration; either we're on the wrong list or
5673                  * destroyed its integrity by doing a deletion.
5674                  */
5675                 goto again;
5676         }
5677         rcu_read_unlock();
5678 
5679         /*
5680          * It could be there's still a few 0-ref events on the list; they'll
5681          * get cleaned up by free_event() -- they'll also still have their
5682          * ref on the rb and will free it whenever they are done with it.
5683          *
5684          * Aside from that, this buffer is 'fully' detached and unmapped,
5685          * undo the VM accounting.
5686          */
5687 
5688         atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5689                         &mmap_user->locked_vm);
5690         atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5691         free_uid(mmap_user);
5692 
5693 out_put:
5694         ring_buffer_put(rb); /* could be last */
5695 }
5696 
5697 static const struct vm_operations_struct perf_mmap_vmops = {
5698         .open           = perf_mmap_open,
5699         .close          = perf_mmap_close, /* non mergeable */
5700         .fault          = perf_mmap_fault,
5701         .page_mkwrite   = perf_mmap_fault,
5702 };
5703 
5704 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5705 {
5706         struct perf_event *event = file->private_data;
5707         unsigned long user_locked, user_lock_limit;
5708         struct user_struct *user = current_user();
5709         unsigned long locked, lock_limit;
5710         struct ring_buffer *rb = NULL;
5711         unsigned long vma_size;
5712         unsigned long nr_pages;
5713         long user_extra = 0, extra = 0;
5714         int ret = 0, flags = 0;
5715 
5716         /*
5717          * Don't allow mmap() of inherited per-task counters. This would
5718          * create a performance issue due to all children writing to the
5719          * same rb.
5720          */
5721         if (event->cpu == -1 && event->attr.inherit)
5722                 return -EINVAL;
5723 
5724         if (!(vma->vm_flags & VM_SHARED))
5725                 return -EINVAL;
5726 
5727         vma_size = vma->vm_end - vma->vm_start;
5728 
5729         if (vma->vm_pgoff == 0) {
5730                 nr_pages = (vma_size / PAGE_SIZE) - 1;
5731         } else {
5732                 /*
5733                  * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5734                  * mapped, all subsequent mappings should have the same size
5735                  * and offset. Must be above the normal perf buffer.
5736                  */
5737                 u64 aux_offset, aux_size;
5738 
5739                 if (!event->rb)
5740                         return -EINVAL;
5741 
5742                 nr_pages = vma_size / PAGE_SIZE;
5743 
5744                 mutex_lock(&event->mmap_mutex);
5745                 ret = -EINVAL;
5746 
5747                 rb = event->rb;
5748                 if (!rb)
5749                         goto aux_unlock;
5750 
5751                 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5752                 aux_size = READ_ONCE(rb->user_page->aux_size);
5753 
5754                 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5755                         goto aux_unlock;
5756 
5757                 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5758                         goto aux_unlock;
5759 
5760                 /* already mapped with a different offset */
5761                 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5762                         goto aux_unlock;
5763 
5764                 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5765                         goto aux_unlock;
5766 
5767                 /* already mapped with a different size */
5768                 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5769                         goto aux_unlock;
5770 
5771                 if (!is_power_of_2(nr_pages))
5772                         goto aux_unlock;
5773 
5774                 if (!atomic_inc_not_zero(&rb->mmap_count))
5775                         goto aux_unlock;
5776 
5777                 if (rb_has_aux(rb)) {
5778                         atomic_inc(&rb->aux_mmap_count);
5779                         ret = 0;
5780                         goto unlock;
5781                 }
5782 
5783                 atomic_set(&rb->aux_mmap_count, 1);
5784                 user_extra = nr_pages;
5785 
5786                 goto accounting;
5787         }
5788 
5789         /*
5790          * If we have rb pages ensure they're a power-of-two number, so we
5791          * can do bitmasks instead of modulo.
5792          */
5793         if (nr_pages != 0 && !is_power_of_2(nr_pages))
5794                 return -EINVAL;
5795 
5796         if (vma_size != PAGE_SIZE * (1 + nr_pages))
5797                 return -EINVAL;
5798 
5799         WARN_ON_ONCE(event->ctx->parent_ctx);
5800 again:
5801         mutex_lock(&event->mmap_mutex);
5802         if (event->rb) {
5803                 if (event->rb->nr_pages != nr_pages) {
5804                         ret = -EINVAL;
5805                         goto unlock;
5806                 }
5807 
5808                 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5809                         /*
5810                          * Raced against perf_mmap_close() through
5811                          * perf_event_set_output(). Try again, hope for better
5812                          * luck.
5813                          */
5814                         mutex_unlock(&event->mmap_mutex);
5815                         goto again;
5816                 }
5817 
5818                 goto unlock;
5819         }
5820 
5821         user_extra = nr_pages + 1;
5822 
5823 accounting:
5824         user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5825 
5826         /*
5827          * Increase the limit linearly with more CPUs:
5828          */
5829         user_lock_limit *= num_online_cpus();
5830 
5831         user_locked = atomic_long_read(&user->locked_vm);
5832 
5833         /*
5834          * sysctl_perf_event_mlock may have changed, so that
5835          *     user->locked_vm > user_lock_limit
5836          */
5837         if (user_locked > user_lock_limit)
5838                 user_locked = user_lock_limit;
5839         user_locked += user_extra;
5840 
5841         if (user_locked <= user_lock_limit) {
5842                 /* charge all to locked_vm */
5843         } else if (atomic_long_read(&user->locked_vm) >= user_lock_limit) {
5844                 /* charge all to pinned_vm */
5845                 extra = user_extra;
5846                 user_extra = 0;
5847         } else {
5848                 /*
5849                  * charge locked_vm until it hits user_lock_limit;
5850                  * charge the rest from pinned_vm
5851                  */
5852                 extra = user_locked - user_lock_limit;
5853                 user_extra -= extra;
5854         }
5855 
5856         lock_limit = rlimit(RLIMIT_MEMLOCK);
5857         lock_limit >>= PAGE_SHIFT;
5858         locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5859 
5860         if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5861                 !capable(CAP_IPC_LOCK)) {
5862                 ret = -EPERM;
5863                 goto unlock;
5864         }
5865 
5866         WARN_ON(!rb && event->rb);
5867 
5868         if (vma->vm_flags & VM_WRITE)
5869                 flags |= RING_BUFFER_WRITABLE;
5870 
5871         if (!rb) {
5872                 rb = rb_alloc(nr_pages,
5873                               event->attr.watermark ? event->attr.wakeup_watermark : 0,
5874                               event->cpu, flags);
5875 
5876                 if (!rb) {
5877                         ret = -ENOMEM;
5878                         goto unlock;
5879                 }
5880 
5881                 atomic_set(&rb->mmap_count, 1);
5882                 rb->mmap_user = get_current_user();
5883                 rb->mmap_locked = extra;
5884 
5885                 ring_buffer_attach(event, rb);
5886 
5887                 perf_event_init_userpage(event);
5888                 perf_event_update_userpage(event);
5889         } else {
5890                 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5891                                    event->attr.aux_watermark, flags);
5892                 if (!ret)
5893                         rb->aux_mmap_locked = extra;
5894         }
5895 
5896 unlock:
5897         if (!ret) {
5898                 atomic_long_add(user_extra, &user->locked_vm);
5899                 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5900 
5901                 atomic_inc(&event->mmap_count);
5902         } else if (rb) {
5903                 atomic_dec(&rb->mmap_count);
5904         }
5905 aux_unlock:
5906         mutex_unlock(&event->mmap_mutex);
5907 
5908         /*
5909          * Since pinned accounting is per vm we cannot allow fork() to copy our
5910          * vma.
5911          */
5912         vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5913         vma->vm_ops = &perf_mmap_vmops;
5914 
5915         if (event->pmu->event_mapped)
5916                 event->pmu->event_mapped(event, vma->vm_mm);
5917 
5918         return ret;
5919 }
5920 
5921 static int perf_fasync(int fd, struct file *filp, int on)
5922 {
5923         struct inode *inode = file_inode(filp);
5924         struct perf_event *event = filp->private_data;
5925         int retval;
5926 
5927         inode_lock(inode);
5928         retval = fasync_helper(fd, filp, on, &event->fasync);
5929         inode_unlock(inode);
5930 
5931         if (retval < 0)
5932                 return retval;
5933 
5934         return 0;
5935 }
5936 
5937 static const struct file_operations perf_fops = {
5938         .llseek                 = no_llseek,
5939         .release                = perf_release,
5940         .read                   = perf_read,
5941         .poll                   = perf_poll,
5942         .unlocked_ioctl         = perf_ioctl,
5943         .compat_ioctl           = perf_compat_ioctl,
5944         .mmap                   = perf_mmap,
5945         .fasync                 = perf_fasync,
5946 };
5947 
5948 /*
5949  * Perf event wakeup
5950  *
5951  * If there's data, ensure we set the poll() state and publish everything
5952  * to user-space before waking everybody up.
5953  */
5954 
5955 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5956 {
5957         /* only the parent has fasync state */
5958         if (event->parent)
5959                 event = event->parent;
5960         return &event->fasync;
5961 }
5962 
5963 void perf_event_wakeup(struct perf_event *event)
5964 {
5965         ring_buffer_wakeup(event);
5966 
5967         if (event->pending_kill) {
5968                 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5969                 event->pending_kill = 0;
5970         }
5971 }
5972 
5973 static void perf_pending_event_disable(struct perf_event *event)
5974 {
5975         int cpu = READ_ONCE(event->pending_disable);
5976 
5977         if (cpu < 0)
5978                 return;
5979 
5980         if (cpu == smp_processor_id()) {
5981                 WRITE_ONCE(event->pending_disable, -1);
5982                 perf_event_disable_local(event);
5983                 return;
5984         }
5985 
5986         /*
5987          *  CPU-A                       CPU-B
5988          *
5989          *  perf_event_disable_inatomic()
5990          *    @pending_disable = CPU-A;
5991          *    irq_work_queue();
5992          *
5993          *  sched-out
5994          *    @pending_disable = -1;
5995          *
5996          *                              sched-in
5997          *                              perf_event_disable_inatomic()
5998          *                                @pending_disable = CPU-B;
5999          *                                irq_work_queue(); // FAILS
6000          *
6001          *  irq_work_run()
6002          *    perf_pending_event()
6003          *
6004          * But the event runs on CPU-B and wants disabling there.
6005          */
6006         irq_work_queue_on(&event->pending, cpu);
6007 }
6008 
6009 static void perf_pending_event(struct irq_work *entry)
6010 {
6011         struct perf_event *event = container_of(entry, struct perf_event, pending);
6012         int rctx;
6013 
6014         rctx = perf_swevent_get_recursion_context();
6015         /*
6016          * If we 'fail' here, that's OK, it means recursion is already disabled
6017          * and we won't recurse 'further'.
6018          */
6019 
6020         perf_pending_event_disable(event);
6021 
6022         if (event->pending_wakeup) {
6023                 event->pending_wakeup = 0;
6024                 perf_event_wakeup(event);
6025         }
6026 
6027         if (rctx >= 0)
6028                 perf_swevent_put_recursion_context(rctx);
6029 }
6030 
6031 /*
6032  * We assume there is only KVM supporting the callbacks.
6033  * Later on, we might change it to a list if there is
6034  * another virtualization implementation supporting the callbacks.
6035  */
6036 struct perf_guest_info_callbacks *perf_guest_cbs;
6037 
6038 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6039 {
6040         perf_guest_cbs = cbs;
6041         return 0;
6042 }
6043 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6044 
6045 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6046 {
6047         perf_guest_cbs = NULL;
6048         return 0;
6049 }
6050 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6051 
6052 static void
6053 perf_output_sample_regs(struct perf_output_handle *handle,
6054                         struct pt_regs *regs, u64 mask)
6055 {
6056         int bit;
6057         DECLARE_BITMAP(_mask, 64);
6058 
6059         bitmap_from_u64(_mask, mask);
6060         for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6061                 u64 val;
6062 
6063                 val = perf_reg_value(regs, bit);
6064                 perf_output_put(handle, val);
6065         }
6066 }
6067 
6068 static void perf_sample_regs_user(struct perf_regs *regs_user,
6069                                   struct pt_regs *regs,
6070                                   struct pt_regs *regs_user_copy)
6071 {
6072         if (user_mode(regs)) {
6073                 regs_user->abi = perf_reg_abi(current);
6074                 regs_user->regs = regs;
6075         } else if (!(current->flags & PF_KTHREAD)) {
6076                 perf_get_regs_user(regs_user, regs, regs_user_copy);
6077         } else {
6078                 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6079                 regs_user->regs = NULL;
6080         }
6081 }
6082 
6083 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6084                                   struct pt_regs *regs)
6085 {
6086         regs_intr->regs = regs;
6087         regs_intr->abi  = perf_reg_abi(current);
6088 }
6089 
6090 
6091 /*
6092  * Get remaining task size from user stack pointer.
6093  *
6094  * It'd be better to take stack vma map and limit this more
6095  * precisely, but there's no way to get it safely under interrupt,
6096  * so using TASK_SIZE as limit.
6097  */
6098 static u64 perf_ustack_task_size(struct pt_regs *regs)
6099 {
6100         unsigned long addr = perf_user_stack_pointer(regs);
6101 
6102         if (!addr || addr >= TASK_SIZE)
6103                 return 0;
6104 
6105         return TASK_SIZE - addr;
6106 }
6107 
6108 static u16
6109 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6110                         struct pt_regs *regs)
6111 {
6112         u64 task_size;
6113 
6114         /* No regs, no stack pointer, no dump. */
6115         if (!regs)
6116                 return 0;
6117 
6118         /*
6119          * Check if we fit in with the requested stack size into the:
6120          * - TASK_SIZE
6121          *   If we don't, we limit the size to the TASK_SIZE.
6122          *
6123          * - remaining sample size
6124          *   If we don't, we customize the stack size to
6125          *   fit in to the remaining sample size.
6126          */
6127 
6128         task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6129         stack_size = min(stack_size, (u16) task_size);
6130 
6131         /* Current header size plus static size and dynamic size. */
6132         header_size += 2 * sizeof(u64);
6133 
6134         /* Do we fit in with the current stack dump size? */
6135         if ((u16) (header_size + stack_size) < header_size) {
6136                 /*
6137                  * If we overflow the maximum size for the sample,
6138                  * we customize the stack dump size to fit in.
6139                  */
6140                 stack_size = USHRT_MAX - header_size - sizeof(u64);
6141                 stack_size = round_up(stack_size, sizeof(u64));
6142         }
6143 
6144         return stack_size;
6145 }
6146 
6147 static void
6148 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6149                           struct pt_regs *regs)
6150 {
6151         /* Case of a kernel thread, nothing to dump */
6152         if (!regs) {
6153                 u64 size = 0;
6154                 perf_output_put(handle, size);
6155         } else {
6156                 unsigned long sp;
6157                 unsigned int rem;
6158                 u64 dyn_size;
6159                 mm_segment_t fs;
6160 
6161                 /*
6162                  * We dump:
6163                  * static size
6164                  *   - the size requested by user or the best one we can fit
6165                  *     in to the sample max size
6166                  * data
6167                  *   - user stack dump data
6168                  * dynamic size
6169                  *   - the actual dumped size
6170                  */
6171 
6172                 /* Static size. */
6173                 perf_output_put(handle, dump_size);
6174 
6175                 /* Data. */
6176                 sp = perf_user_stack_pointer(regs);
6177                 fs = get_fs();
6178                 set_fs(USER_DS);
6179                 rem = __output_copy_user(handle, (void *) sp, dump_size);
6180                 set_fs(fs);
6181                 dyn_size = dump_size - rem;
6182 
6183                 perf_output_skip(handle, rem);
6184 
6185                 /* Dynamic size. */
6186                 perf_output_put(handle, dyn_size);
6187         }
6188 }
6189 
6190 static void __perf_event_header__init_id(struct perf_event_header *header,
6191                                          struct perf_sample_data *data,
6192                                          struct perf_event *event)
6193 {
6194         u64 sample_type = event->attr.sample_type;
6195 
6196         data->type = sample_type;
6197         header->size += event->id_header_size;
6198 
6199         if (sample_type & PERF_SAMPLE_TID) {
6200                 /* namespace issues */
6201                 data->tid_entry.pid = perf_event_pid(event, current);
6202                 data->tid_entry.tid = perf_event_tid(event, current);
6203         }
6204 
6205         if (sample_type & PERF_SAMPLE_TIME)
6206                 data->time = perf_event_clock(event);
6207 
6208         if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6209                 data->id = primary_event_id(event);
6210 
6211         if (sample_type & PERF_SAMPLE_STREAM_ID)
6212                 data->stream_id = event->id;
6213 
6214         if (sample_type & PERF_SAMPLE_CPU) {
6215                 data->cpu_entry.cpu      = raw_smp_processor_id();
6216                 data->cpu_entry.reserved = 0;
6217         }
6218 }
6219 
6220 void perf_event_header__init_id(struct perf_event_header *header,
6221                                 struct perf_sample_data *data,
6222                                 struct perf_event *event)
6223 {
6224         if (event->attr.sample_id_all)
6225                 __perf_event_header__init_id(header, data, event);
6226 }
6227 
6228 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6229                                            struct perf_sample_data *data)
6230 {
6231         u64 sample_type = data->type;
6232 
6233         if (sample_type & PERF_SAMPLE_TID)
6234                 perf_output_put(handle, data->tid_entry);
6235 
6236         if (sample_type & PERF_SAMPLE_TIME)
6237                 perf_output_put(handle, data->time);
6238 
6239         if (sample_type & PERF_SAMPLE_ID)
6240                 perf_output_put(handle, data->id);
6241 
6242         if (sample_type & PERF_SAMPLE_STREAM_ID)
6243                 perf_output_put(handle, data->stream_id);
6244 
6245         if (sample_type & PERF_SAMPLE_CPU)
6246                 perf_output_put(handle, data->cpu_entry);
6247 
6248         if (sample_type & PERF_SAMPLE_IDENTIFIER)
6249                 perf_output_put(handle, data->id);
6250 }
6251 
6252 void perf_event__output_id_sample(struct perf_event *event,
6253                                   struct perf_output_handle *handle,
6254                                   struct perf_sample_data *sample)
6255 {
6256         if (event->attr.sample_id_all)
6257                 __perf_event__output_id_sample(handle, sample);
6258 }
6259 
6260 static void perf_output_read_one(struct perf_output_handle *handle,
6261                                  struct perf_event *event,
6262                                  u64 enabled, u64 running)
6263 {
6264         u64 read_format = event->attr.read_format;
6265         u64 values[4];
6266         int n = 0;
6267 
6268         values[n++] = perf_event_count(event);
6269         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6270                 values[n++] = enabled +
6271                         atomic64_read(&event->child_total_time_enabled);
6272         }
6273         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6274                 values[n++] = running +
6275                         atomic64_read(&event->child_total_time_running);
6276         }
6277         if (read_format & PERF_FORMAT_ID)
6278                 values[n++] = primary_event_id(event);
6279 
6280         __output_copy(handle, values, n * sizeof(u64));
6281 }
6282 
6283 static void perf_output_read_group(struct perf_output_handle *handle,
6284                             struct perf_event *event,
6285                             u64 enabled, u64 running)
6286 {
6287         struct perf_event *leader = event->group_leader, *sub;
6288         u64 read_format = event->attr.read_format;
6289         u64 values[5];
6290         int n = 0;
6291 
6292         values[n++] = 1 + leader->nr_siblings;
6293 
6294         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6295                 values[n++] = enabled;
6296 
6297         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6298                 values[n++] = running;
6299 
6300         if ((leader != event) &&
6301             (leader->state == PERF_EVENT_STATE_ACTIVE))
6302                 leader->pmu->read(leader);
6303 
6304         values[n++] = perf_event_count(leader);
6305         if (read_format & PERF_FORMAT_ID)
6306                 values[n++] = primary_event_id(leader);
6307 
6308         __output_copy(handle, values, n * sizeof(u64));
6309 
6310         for_each_sibling_event(sub, leader) {
6311                 n = 0;
6312 
6313                 if ((sub != event) &&
6314                     (sub->state == PERF_EVENT_STATE_ACTIVE))
6315                         sub->pmu->read(sub);
6316 
6317                 values[n++] = perf_event_count(sub);
6318                 if (read_format & PERF_FORMAT_ID)
6319                         values[n++] = primary_event_id(sub);
6320 
6321                 __output_copy(handle, values, n * sizeof(u64));
6322         }
6323 }
6324 
6325 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6326                                  PERF_FORMAT_TOTAL_TIME_RUNNING)
6327 
6328 /*
6329  * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6330  *
6331  * The problem is that its both hard and excessively expensive to iterate the
6332  * child list, not to mention that its impossible to IPI the children running
6333  * on another CPU, from interrupt/NMI context.
6334  */
6335 static void perf_output_read(struct perf_output_handle *handle,
6336                              struct perf_event *event)
6337 {
6338         u64 enabled = 0, running = 0, now;
6339         u64 read_format = event->attr.read_format;
6340 
6341         /*
6342          * compute total_time_enabled, total_time_running
6343          * based on snapshot values taken when the event
6344          * was last scheduled in.
6345          *
6346          * we cannot simply called update_context_time()
6347          * because of locking issue as we are called in
6348          * NMI context
6349          */
6350         if (read_format & PERF_FORMAT_TOTAL_TIMES)
6351                 calc_timer_values(event, &now, &enabled, &running);
6352 
6353         if (event->attr.read_format & PERF_FORMAT_GROUP)
6354                 perf_output_read_group(handle, event, enabled, running);
6355         else
6356                 perf_output_read_one(handle, event, enabled, running);
6357 }
6358 
6359 void perf_output_sample(struct perf_output_handle *handle,
6360                         struct perf_event_header *header,
6361                         struct perf_sample_data *data,
6362                         struct perf_event *event)
6363 {
6364         u64 sample_type = data->type;
6365 
6366         perf_output_put(handle, *header);
6367 
6368         if (sample_type & PERF_SAMPLE_IDENTIFIER)
6369                 perf_output_put(handle, data->id);
6370 
6371         if (sample_type & PERF_SAMPLE_IP)
6372                 perf_output_put(handle, data->ip);
6373 
6374         if (sample_type & PERF_SAMPLE_TID)
6375                 perf_output_put(handle, data->tid_entry);
6376 
6377         if (sample_type & PERF_SAMPLE_TIME)
6378                 perf_output_put(handle, data->time);
6379 
6380         if (sample_type & PERF_SAMPLE_ADDR)
6381                 perf_output_put(handle, data->addr);
6382 
6383         if (sample_type & PERF_SAMPLE_ID)
6384                 perf_output_put(handle, data->id);
6385 
6386         if (sample_type & PERF_SAMPLE_STREAM_ID)
6387                 perf_output_put(handle, data->stream_id);
6388 
6389         if (sample_type & PERF_SAMPLE_CPU)
6390                 perf_output_put(handle, data->cpu_entry);
6391 
6392         if (sample_type & PERF_SAMPLE_PERIOD)
6393                 perf_output_put(handle, data->period);
6394 
6395         if (sample_type & PERF_SAMPLE_READ)
6396                 perf_output_read(handle, event);
6397 
6398         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6399                 int size = 1;
6400 
6401                 size += data->callchain->nr;
6402                 size *= sizeof(u64);
6403                 __output_copy(handle, data->callchain, size);
6404         }
6405 
6406         if (sample_type & PERF_SAMPLE_RAW) {
6407                 struct perf_raw_record *raw = data->raw;
6408 
6409                 if (raw) {
6410                         struct perf_raw_frag *frag = &raw->frag;
6411 
6412                         perf_output_put(handle, raw->size);
6413                         do {
6414                                 if (frag->copy) {
6415                                         __output_custom(handle, frag->copy,
6416                                                         frag->data, frag->size);
6417                                 } else {
6418                                         __output_copy(handle, frag->data,
6419                                                       frag->size);
6420                                 }
6421                                 if (perf_raw_frag_last(frag))
6422                                         break;
6423                                 frag = frag->next;
6424                         } while (1);
6425                         if (frag->pad)
6426                                 __output_skip(handle, NULL, frag->pad);
6427                 } else {
6428                         struct {
6429                                 u32     size;
6430                                 u32     data;
6431                         } raw = {
6432                                 .size = sizeof(u32),
6433                                 .data = 0,
6434                         };
6435                         perf_output_put(handle, raw);
6436                 }
6437         }
6438 
6439         if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6440                 if (data->br_stack) {
6441                         size_t size;
6442 
6443                         size = data->br_stack->nr
6444                              * sizeof(struct perf_branch_entry);
6445 
6446                         perf_output_put(handle, data->br_stack->nr);
6447                         perf_output_copy(handle, data->br_stack->entries, size);
6448                 } else {
6449                         /*
6450                          * we always store at least the value of nr
6451                          */
6452                         u64 nr = 0;
6453                         perf_output_put(handle, nr);
6454                 }
6455         }
6456 
6457         if (sample_type & PERF_SAMPLE_REGS_USER) {
6458                 u64 abi = data->regs_user.abi;
6459 
6460                 /*
6461                  * If there are no regs to dump, notice it through
6462                  * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6463                  */
6464                 perf_output_put(handle, abi);
6465 
6466                 if (abi) {
6467                         u64 mask = event->attr.sample_regs_user;
6468                         perf_output_sample_regs(handle,
6469                                                 data->regs_user.regs,
6470                                                 mask);
6471                 }
6472         }
6473 
6474         if (sample_type & PERF_SAMPLE_STACK_USER) {
6475                 perf_output_sample_ustack(handle,
6476                                           data->stack_user_size,
6477                                           data->regs_user.regs);
6478         }
6479 
6480         if (sample_type & PERF_SAMPLE_WEIGHT)
6481                 perf_output_put(handle, data->weight);
6482 
6483         if (sample_type & PERF_SAMPLE_DATA_SRC)
6484                 perf_output_put(handle, data->data_src.val);
6485 
6486         if (sample_type & PERF_SAMPLE_TRANSACTION)
6487                 perf_output_put(handle, data->txn);
6488 
6489         if (sample_type & PERF_SAMPLE_REGS_INTR) {
6490                 u64 abi = data->regs_intr.abi;
6491                 /*
6492                  * If there are no regs to dump, notice it through
6493                  * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6494                  */
6495                 perf_output_put(handle, abi);
6496 
6497                 if (abi) {
6498                         u64 mask = event->attr.sample_regs_intr;
6499 
6500                         perf_output_sample_regs(handle,
6501                                                 data->regs_intr.regs,
6502                                                 mask);
6503                 }
6504         }
6505 
6506         if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6507                 perf_output_put(handle, data->phys_addr);
6508 
6509         if (!event->attr.watermark) {
6510                 int wakeup_events = event->attr.wakeup_events;
6511 
6512                 if (wakeup_events) {
6513                         struct ring_buffer *rb = handle->rb;
6514                         int events = local_inc_return(&rb->events);
6515 
6516                         if (events >= wakeup_events) {
6517                                 local_sub(wakeup_events, &rb->events);
6518                                 local_inc(&rb->wakeup);
6519                         }
6520                 }
6521         }
6522 }
6523 
6524 static u64 perf_virt_to_phys(u64 virt)
6525 {
6526         u64 phys_addr = 0;
6527         struct page *p = NULL;
6528 
6529         if (!virt)
6530                 return 0;
6531 
6532         if (virt >= TASK_SIZE) {
6533                 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6534                 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6535                     !(virt >= VMALLOC_START && virt < VMALLOC_END))
6536                         phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6537         } else {
6538                 /*
6539                  * Walking the pages tables for user address.
6540                  * Interrupts are disabled, so it prevents any tear down
6541                  * of the page tables.
6542                  * Try IRQ-safe __get_user_pages_fast first.
6543                  * If failed, leave phys_addr as 0.
6544                  */
6545                 if (current->mm != NULL) {
6546                         pagefault_disable();
6547                         if (__get_user_pages_fast(virt, 1, 0, &p) == 1)
6548                                 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6549                         pagefault_enable();
6550                 }
6551 
6552                 if (p)
6553                         put_page(p);
6554         }
6555 
6556         return phys_addr;
6557 }
6558 
6559 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6560 
6561 struct perf_callchain_entry *
6562 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6563 {
6564         bool kernel = !event->attr.exclude_callchain_kernel;
6565         bool user   = !event->attr.exclude_callchain_user;
6566         /* Disallow cross-task user callchains. */
6567         bool crosstask = event->ctx->task && event->ctx->task != current;
6568         const u32 max_stack = event->attr.sample_max_stack;
6569         struct perf_callchain_entry *callchain;
6570 
6571         if (!kernel && !user)
6572                 return &__empty_callchain;
6573 
6574         callchain = get_perf_callchain(regs, 0, kernel, user,
6575                                        max_stack, crosstask, true);
6576         return callchain ?: &__empty_callchain;
6577 }
6578 
6579 void perf_prepare_sample(struct perf_event_header *header,
6580                          struct perf_sample_data *data,
6581                          struct perf_event *event,
6582                          struct pt_regs *regs)
6583 {
6584         u64 sample_type = event->attr.sample_type;
6585 
6586         header->type = PERF_RECORD_SAMPLE;
6587         header->size = sizeof(*header) + event->header_size;
6588 
6589         header->misc = 0;
6590         header->misc |= perf_misc_flags(regs);
6591 
6592         __perf_event_header__init_id(header, data, event);
6593 
6594         if (sample_type & PERF_SAMPLE_IP)
6595                 data->ip = perf_instruction_pointer(regs);
6596 
6597         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6598                 int size = 1;
6599 
6600                 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6601                         data->callchain = perf_callchain(event, regs);
6602 
6603                 size += data->callchain->nr;
6604 
6605                 header->size += size * sizeof(u64);
6606         }
6607 
6608         if (sample_type & PERF_SAMPLE_RAW) {
6609                 struct perf_raw_record *raw = data->raw;
6610                 int size;
6611 
6612                 if (raw) {
6613                         struct perf_raw_frag *frag = &raw->frag;
6614                         u32 sum = 0;
6615 
6616                         do {
6617                                 sum += frag->size;
6618                                 if (perf_raw_frag_last(frag))
6619                                         break;
6620                                 frag = frag->next;
6621                         } while (1);
6622 
6623                         size = round_up(sum + sizeof(u32), sizeof(u64));
6624                         raw->size = size - sizeof(u32);
6625                         frag->pad = raw->size - sum;
6626                 } else {
6627                         size = sizeof(u64);
6628                 }
6629 
6630                 header->size += size;
6631         }
6632 
6633         if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6634                 int size = sizeof(u64); /* nr */
6635                 if (data->br_stack) {
6636                         size += data->br_stack->nr
6637                               * sizeof(struct perf_branch_entry);
6638                 }
6639                 header->size += size;
6640         }
6641 
6642         if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6643                 perf_sample_regs_user(&data->regs_user, regs,
6644                                       &data->regs_user_copy);
6645 
6646         if (sample_type & PERF_SAMPLE_REGS_USER) {
6647                 /* regs dump ABI info */
6648                 int size = sizeof(u64);
6649 
6650                 if (data->regs_user.regs) {
6651                         u64 mask = event->attr.sample_regs_user;
6652                         size += hweight64(mask) * sizeof(u64);
6653                 }
6654 
6655                 header->size += size;
6656         }
6657 
6658         if (sample_type & PERF_SAMPLE_STACK_USER) {
6659                 /*
6660                  * Either we need PERF_SAMPLE_STACK_USER bit to be always
6661                  * processed as the last one or have additional check added
6662                  * in case new sample type is added, because we could eat
6663                  * up the rest of the sample size.
6664                  */
6665                 u16 stack_size = event->attr.sample_stack_user;
6666                 u16 size = sizeof(u64);
6667 
6668                 stack_size = perf_sample_ustack_size(stack_size, header->size,
6669                                                      data->regs_user.regs);
6670 
6671                 /*
6672                  * If there is something to dump, add space for the dump
6673                  * itself and for the field that tells the dynamic size,
6674                  * which is how many have been actually dumped.
6675                  */
6676                 if (stack_size)
6677                         size += sizeof(u64) + stack_size;
6678 
6679                 data->stack_user_size = stack_size;
6680                 header->size += size;
6681         }
6682 
6683         if (sample_type & PERF_SAMPLE_REGS_INTR) {
6684                 /* regs dump ABI info */
6685                 int size = sizeof(u64);
6686 
6687                 perf_sample_regs_intr(&data->regs_intr, regs);
6688 
6689                 if (data->regs_intr.regs) {
6690                         u64 mask = event->attr.sample_regs_intr;
6691 
6692                         size += hweight64(mask) * sizeof(u64);
6693                 }
6694 
6695                 header->size += size;
6696         }
6697 
6698         if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6699                 data->phys_addr = perf_virt_to_phys(data->addr);
6700 }
6701 
6702 static __always_inline int
6703 __perf_event_output(struct perf_event *event,
6704                     struct perf_sample_data *data,
6705                     struct pt_regs *regs,
6706                     int (*output_begin)(struct perf_output_handle *,
6707                                         struct perf_event *,
6708                                         unsigned int))
6709 {
6710         struct perf_output_handle handle;
6711         struct perf_event_header header;
6712         int err;
6713 
6714         /* protect the callchain buffers */
6715         rcu_read_lock();
6716 
6717         perf_prepare_sample(&header, data, event, regs);
6718 
6719         err = output_begin(&handle, event, header.size);
6720         if (err)
6721                 goto exit;
6722 
6723         perf_output_sample(&handle, &header, data, event);
6724 
6725         perf_output_end(&handle);
6726 
6727 exit:
6728         rcu_read_unlock();
6729         return err;
6730 }
6731 
6732 void
6733 perf_event_output_forward(struct perf_event *event,
6734                          struct perf_sample_data *data,
6735                          struct pt_regs *regs)
6736 {
6737         __perf_event_output(event, data, regs, perf_output_begin_forward);
6738 }
6739 
6740 void
6741 perf_event_output_backward(struct perf_event *event,
6742                            struct perf_sample_data *data,
6743                            struct pt_regs *regs)
6744 {
6745         __perf_event_output(event, data, regs, perf_output_begin_backward);
6746 }
6747 
6748 int
6749 perf_event_output(struct perf_event *event,
6750                   struct perf_sample_data *data,
6751                   struct pt_regs *regs)
6752 {
6753         return __perf_event_output(event, data, regs, perf_output_begin);
6754 }
6755 
6756 /*
6757  * read event_id
6758  */
6759 
6760 struct perf_read_event {
6761         struct perf_event_header        header;
6762 
6763         u32                             pid;
6764         u32                             tid;
6765 };
6766 
6767 static void
6768 perf_event_read_event(struct perf_event *event,
6769                         struct task_struct *task)
6770 {
6771         struct perf_output_handle handle;
6772         struct perf_sample_data sample;
6773         struct perf_read_event read_event = {
6774                 .header = {
6775                         .type = PERF_RECORD_READ,
6776                         .misc = 0,
6777                         .size = sizeof(read_event) + event->read_size,
6778                 },
6779                 .pid = perf_event_pid(event, task),
6780                 .tid = perf_event_tid(event, task),
6781         };
6782         int ret;
6783 
6784         perf_event_header__init_id(&read_event.header, &sample, event);
6785         ret = perf_output_begin(&handle, event, read_event.header.size);
6786         if (ret)
6787                 return;
6788 
6789         perf_output_put(&handle, read_event);
6790         perf_output_read(&handle, event);
6791         perf_event__output_id_sample(event, &handle, &sample);
6792 
6793         perf_output_end(&handle);
6794 }
6795 
6796 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6797 
6798 static void
6799 perf_iterate_ctx(struct perf_event_context *ctx,
6800                    perf_iterate_f output,
6801                    void *data, bool all)
6802 {
6803         struct perf_event *event;
6804 
6805         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6806                 if (!all) {
6807                         if (event->state < PERF_EVENT_STATE_INACTIVE)
6808                                 continue;
6809                         if (!event_filter_match(event))
6810                                 continue;
6811                 }
6812 
6813                 output(event, data);
6814         }
6815 }
6816 
6817 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6818 {
6819         struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6820         struct perf_event *event;
6821 
6822         list_for_each_entry_rcu(event, &pel->list, sb_list) {
6823                 /*
6824                  * Skip events that are not fully formed yet; ensure that
6825                  * if we observe event->ctx, both event and ctx will be
6826                  * complete enough. See perf_install_in_context().
6827                  */
6828                 if (!smp_load_acquire(&event->ctx))
6829                         continue;
6830 
6831                 if (event->state < PERF_EVENT_STATE_INACTIVE)
6832                         continue;
6833                 if (!event_filter_match(event))
6834                         continue;
6835                 output(event, data);
6836         }
6837 }
6838 
6839 /*
6840  * Iterate all events that need to receive side-band events.
6841  *
6842  * For new callers; ensure that account_pmu_sb_event() includes
6843  * your event, otherwise it might not get delivered.
6844  */
6845 static void
6846 perf_iterate_sb(perf_iterate_f output, void *data,
6847                struct perf_event_context *task_ctx)
6848 {
6849         struct perf_event_context *ctx;
6850         int ctxn;
6851 
6852         rcu_read_lock();
6853         preempt_disable();
6854 
6855         /*
6856          * If we have task_ctx != NULL we only notify the task context itself.
6857          * The task_ctx is set only for EXIT events before releasing task
6858          * context.
6859          */
6860         if (task_ctx) {
6861                 perf_iterate_ctx(task_ctx, output, data, false);
6862                 goto done;
6863         }
6864 
6865         perf_iterate_sb_cpu(output, data);
6866 
6867         for_each_task_context_nr(ctxn) {
6868                 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6869                 if (ctx)
6870                         perf_iterate_ctx(ctx, output, data, false);
6871         }
6872 done:
6873         preempt_enable();
6874         rcu_read_unlock();
6875 }
6876 
6877 /*
6878  * Clear all file-based filters at exec, they'll have to be
6879  * re-instated when/if these objects are mmapped again.
6880  */
6881 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6882 {
6883         struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6884         struct perf_addr_filter *filter;
6885         unsigned int restart = 0, count = 0;
6886         unsigned long flags;
6887 
6888         if (!has_addr_filter(event))
6889                 return;
6890 
6891         raw_spin_lock_irqsave(&ifh->lock, flags);
6892         list_for_each_entry(filter, &ifh->list, entry) {
6893                 if (filter->path.dentry) {
6894                         event->addr_filter_ranges[count].start = 0;
6895                         event->addr_filter_ranges[count].size = 0;
6896                         restart++;
6897                 }
6898 
6899                 count++;
6900         }
6901 
6902         if (restart)
6903                 event->addr_filters_gen++;
6904         raw_spin_unlock_irqrestore(&ifh->lock, flags);
6905 
6906         if (restart)
6907                 perf_event_stop(event, 1);
6908 }
6909 
6910 void perf_event_exec(void)
6911 {
6912         struct perf_event_context *ctx;
6913         int ctxn;
6914 
6915         rcu_read_lock();
6916         for_each_task_context_nr(ctxn) {
6917                 ctx = current->perf_event_ctxp[ctxn];
6918                 if (!ctx)
6919                         continue;
6920 
6921                 perf_event_enable_on_exec(ctxn);
6922 
6923                 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6924                                    true);
6925         }
6926         rcu_read_unlock();
6927 }
6928 
6929 struct remote_output {
6930         struct ring_buffer      *rb;
6931         int                     err;
6932 };
6933 
6934 static void __perf_event_output_stop(struct perf_event *event, void *data)
6935 {
6936         struct perf_event *parent = event->parent;
6937         struct remote_output *ro = data;
6938         struct ring_buffer *rb = ro->rb;
6939         struct stop_event_data sd = {
6940                 .event  = event,
6941         };
6942 
6943         if (!has_aux(event))
6944                 return;
6945 
6946         if (!parent)
6947                 parent = event;
6948 
6949         /*
6950          * In case of inheritance, it will be the parent that links to the
6951          * ring-buffer, but it will be the child that's actually using it.
6952          *
6953          * We are using event::rb to determine if the event should be stopped,
6954          * however this may race with ring_buffer_attach() (through set_output),
6955          * which will make us skip the event that actually needs to be stopped.
6956          * So ring_buffer_attach() has to stop an aux event before re-assigning
6957          * its rb pointer.
6958          */
6959         if (rcu_dereference(parent->rb) == rb)
6960                 ro->err = __perf_event_stop(&sd);
6961 }
6962 
6963 static int __perf_pmu_output_stop(void *info)
6964 {
6965         struct perf_event *event = info;
6966         struct pmu *pmu = event->ctx->pmu;
6967         struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6968         struct remote_output ro = {
6969                 .rb     = event->rb,
6970         };
6971 
6972         rcu_read_lock();
6973         perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6974         if (cpuctx->task_ctx)
6975                 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6976                                    &ro, false);
6977         rcu_read_unlock();
6978 
6979         return ro.err;
6980 }
6981 
6982 static void perf_pmu_output_stop(struct perf_event *event)
6983 {
6984         struct perf_event *iter;
6985         int err, cpu;
6986 
6987 restart:
6988         rcu_read_lock();
6989         list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6990                 /*
6991                  * For per-CPU events, we need to make sure that neither they
6992                  * nor their children are running; for cpu==-1 events it's
6993                  * sufficient to stop the event itself if it's active, since
6994                  * it can't have children.
6995                  */
6996                 cpu = iter->cpu;
6997                 if (cpu == -1)
6998                         cpu = READ_ONCE(iter->oncpu);
6999 
7000                 if (cpu == -1)
7001                         continue;
7002 
7003                 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7004                 if (err == -EAGAIN) {
7005                         rcu_read_unlock();
7006                         goto restart;
7007                 }
7008         }
7009         rcu_read_unlock();
7010 }
7011 
7012 /*
7013  * task tracking -- fork/exit
7014  *
7015  * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7016  */
7017 
7018 struct perf_task_event {
7019         struct task_struct              *task;
7020         struct perf_event_context       *task_ctx;
7021 
7022         struct {
7023                 struct perf_event_header        header;
7024 
7025                 u32                             pid;
7026                 u32                             ppid;
7027                 u32                             tid;
7028                 u32                             ptid;
7029                 u64                             time;
7030         } event_id;
7031 };
7032 
7033 static int perf_event_task_match(struct perf_event *event)
7034 {
7035         return event->attr.comm  || event->attr.mmap ||
7036                event->attr.mmap2 || event->attr.mmap_data ||
7037                event->attr.task;
7038 }
7039 
7040 static void perf_event_task_output(struct perf_event *event,
7041                                    void *data)
7042 {
7043         struct perf_task_event *task_event = data;
7044         struct perf_output_handle handle;
7045         struct perf_sample_data sample;
7046         struct task_struct *task = task_event->task;
7047         int ret, size = task_event->event_id.header.size;
7048 
7049         if (!perf_event_task_match(event))
7050                 return;
7051 
7052         perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7053 
7054         ret = perf_output_begin(&handle, event,
7055                                 task_event->event_id.header.size);
7056         if (ret)
7057                 goto out;
7058 
7059         task_event->event_id.pid = perf_event_pid(event, task);
7060         task_event->event_id.tid = perf_event_tid(event, task);
7061 
7062         if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7063                 task_event->event_id.ppid = perf_event_pid(event,
7064                                                         task->real_parent);
7065                 task_event->event_id.ptid = perf_event_pid(event,
7066                                                         task->real_parent);
7067         } else {  /* PERF_RECORD_FORK */
7068                 task_event->event_id.ppid = perf_event_pid(event, current);
7069                 task_event->event_id.ptid = perf_event_tid(event, current);
7070         }
7071 
7072         task_event->event_id.time = perf_event_clock(event);
7073 
7074         perf_output_put(&handle, task_event->event_id);
7075 
7076         perf_event__output_id_sample(event, &handle, &sample);
7077 
7078         perf_output_end(&handle);
7079 out:
7080         task_event->event_id.header.size = size;
7081 }
7082 
7083 static void perf_event_task(struct task_struct *task,
7084                               struct perf_event_context *task_ctx,
7085                               int new)
7086 {
7087         struct perf_task_event task_event;
7088 
7089         if (!atomic_read(&nr_comm_events) &&
7090             !atomic_read(&nr_mmap_events) &&
7091             !atomic_read(&nr_task_events))
7092                 return;
7093 
7094         task_event = (struct perf_task_event){
7095                 .task     = task,
7096                 .task_ctx = task_ctx,
7097                 .event_id    = {
7098                         .header = {
7099                                 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7100                                 .misc = 0,
7101                                 .size = sizeof(task_event.event_id),
7102                         },
7103                         /* .pid  */
7104                         /* .ppid */
7105                         /* .tid  */
7106                         /* .ptid */
7107                         /* .time */
7108                 },
7109         };
7110 
7111         perf_iterate_sb(perf_event_task_output,
7112                        &task_event,
7113                        task_ctx);
7114 }
7115 
7116 void perf_event_fork(struct task_struct *task)
7117 {
7118         perf_event_task(task, NULL, 1);
7119         perf_event_namespaces(task);
7120 }
7121 
7122 /*
7123  * comm tracking
7124  */
7125 
7126 struct perf_comm_event {
7127         struct task_struct      *task;
7128         char                    *comm;
7129         int                     comm_size;
7130 
7131         struct {
7132                 struct perf_event_header        header;
7133 
7134                 u32                             pid;
7135                 u32                             tid;
7136         } event_id;
7137 };
7138 
7139 static int perf_event_comm_match(struct perf_event *event)
7140 {
7141         return event->attr.comm;
7142 }
7143 
7144 static void perf_event_comm_output(struct perf_event *event,
7145                                    void *data)
7146 {
7147         struct perf_comm_event *comm_event = data;
7148         struct perf_output_handle handle;
7149         struct perf_sample_data sample;
7150         int size = comm_event->event_id.header.size;
7151         int ret;
7152 
7153         if (!perf_event_comm_match(event))
7154                 return;
7155 
7156         perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7157         ret = perf_output_begin(&handle, event,
7158                                 comm_event->event_id.header.size);
7159 
7160         if (ret)
7161                 goto out;
7162 
7163         comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7164         comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7165 
7166         perf_output_put(&handle, comm_event->event_id);
7167         __output_copy(&handle, comm_event->comm,
7168                                    comm_event->comm_size);
7169 
7170         perf_event__output_id_sample(event, &handle, &sample);
7171 
7172         perf_output_end(&handle);
7173 out:
7174         comm_event->event_id.header.size = size;
7175 }
7176 
7177 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7178 {
7179         char comm[TASK_COMM_LEN];
7180         unsigned int size;
7181 
7182         memset(comm, 0, sizeof(comm));
7183         strlcpy(comm, comm_event->task->comm, sizeof(comm));
7184         size = ALIGN(strlen(comm)+1, sizeof(u64));
7185 
7186         comm_event->comm = comm;
7187         comm_event->comm_size = size;
7188 
7189         comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7190 
7191         perf_iterate_sb(perf_event_comm_output,
7192                        comm_event,
7193                        NULL);
7194 }
7195 
7196 void perf_event_comm(struct task_struct *task, bool exec)
7197 {
7198         struct perf_comm_event comm_event;
7199 
7200         if (!atomic_read(&nr_comm_events))
7201                 return;
7202 
7203         comm_event = (struct perf_comm_event){
7204                 .task   = task,
7205                 /* .comm      */
7206                 /* .comm_size */
7207                 .event_id  = {
7208                         .header = {
7209                                 .type = PERF_RECORD_COMM,
7210                                 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7211                                 /* .size */
7212                         },
7213                         /* .pid */
7214                         /* .tid */
7215                 },
7216         };
7217 
7218         perf_event_comm_event(&comm_event);
7219 }
7220 
7221 /*
7222  * namespaces tracking
7223  */
7224 
7225 struct perf_namespaces_event {
7226         struct task_struct              *task;
7227 
7228         struct {
7229                 struct perf_event_header        header;
7230 
7231                 u32                             pid;
7232                 u32                             tid;
7233                 u64                             nr_namespaces;
7234                 struct perf_ns_link_info        link_info[NR_NAMESPACES];
7235         } event_id;
7236 };
7237 
7238 static int perf_event_namespaces_match(struct perf_event *event)
7239 {
7240         return event->attr.namespaces;
7241 }
7242 
7243 static void perf_event_namespaces_output(struct perf_event *event,
7244                                          void *data)
7245 {
7246         struct perf_namespaces_event *namespaces_event = data;
7247         struct perf_output_handle handle;
7248         struct perf_sample_data sample;
7249         u16 header_size = namespaces_event->event_id.header.size;
7250         int ret;
7251 
7252         if (!perf_event_namespaces_match(event))
7253                 return;
7254 
7255         perf_event_header__init_id(&namespaces_event->event_id.header,
7256                                    &sample, event);
7257         ret = perf_output_begin(&handle, event,
7258                                 namespaces_event->event_id.header.size);
7259         if (ret)
7260                 goto out;
7261 
7262         namespaces_event->event_id.pid = perf_event_pid(event,
7263                                                         namespaces_event->task);
7264         namespaces_event->event_id.tid = perf_event_tid(event,
7265                                                         namespaces_event->task);
7266 
7267         perf_output_put(&handle, namespaces_event->event_id);
7268 
7269         perf_event__output_id_sample(event, &handle, &sample);
7270 
7271         perf_output_end(&handle);
7272 out:
7273         namespaces_event->event_id.header.size = header_size;
7274 }
7275 
7276 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7277                                    struct task_struct *task,
7278                                    const struct proc_ns_operations *ns_ops)
7279 {
7280         struct path ns_path;
7281         struct inode *ns_inode;
7282         void *error;
7283 
7284         error = ns_get_path(&ns_path, task, ns_ops);
7285         if (!error) {
7286                 ns_inode = ns_path.dentry->d_inode;
7287                 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7288                 ns_link_info->ino = ns_inode->i_ino;
7289                 path_put(&ns_path);
7290         }
7291 }
7292 
7293 void perf_event_namespaces(struct task_struct *task)
7294 {
7295         struct perf_namespaces_event namespaces_event;
7296         struct perf_ns_link_info *ns_link_info;
7297 
7298         if (!atomic_read(&nr_namespaces_events))
7299                 return;
7300 
7301         namespaces_event = (struct perf_namespaces_event){
7302                 .task   = task,
7303                 .event_id  = {
7304                         .header = {
7305                                 .type = PERF_RECORD_NAMESPACES,
7306                                 .misc = 0,
7307                                 .size = sizeof(namespaces_event.event_id),
7308                         },
7309                         /* .pid */
7310                         /* .tid */
7311                         .nr_namespaces = NR_NAMESPACES,
7312                         /* .link_info[NR_NAMESPACES] */
7313                 },
7314         };
7315 
7316         ns_link_info = namespaces_event.event_id.link_info;
7317 
7318         perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7319                                task, &mntns_operations);
7320 
7321 #ifdef CONFIG_USER_NS
7322         perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7323                                task, &userns_operations);
7324 #endif
7325 #ifdef CONFIG_NET_NS
7326         perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7327                                task, &netns_operations);
7328 #endif
7329 #ifdef CONFIG_UTS_NS
7330         perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7331                                task, &utsns_operations);
7332 #endif
7333 #ifdef CONFIG_IPC_NS
7334         perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7335                                task, &ipcns_operations);
7336 #endif
7337 #ifdef CONFIG_PID_NS
7338         perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7339                                task, &pidns_operations);
7340 #endif
7341 #ifdef CONFIG_CGROUPS
7342         perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7343                                task, &cgroupns_operations);
7344 #endif
7345 
7346         perf_iterate_sb(perf_event_namespaces_output,
7347                         &namespaces_event,
7348                         NULL);
7349 }
7350 
7351 /*
7352  * mmap tracking
7353  */
7354 
7355 struct perf_mmap_event {
7356         struct vm_area_struct   *vma;
7357 
7358         const char              *file_name;
7359         int                     file_size;
7360         int                     maj, min;
7361         u64                     ino;
7362         u64                     ino_generation;
7363         u32                     prot, flags;
7364 
7365         struct {
7366                 struct perf_event_header        header;
7367 
7368                 u32                             pid;
7369                 u32                             tid;
7370                 u64                             start;
7371                 u64                             len;
7372                 u64                             pgoff;
7373         } event_id;
7374 };
7375 
7376 static int perf_event_mmap_match(struct perf_event *event,
7377                                  void *data)
7378 {
7379         struct perf_mmap_event *mmap_event = data;
7380         struct vm_area_struct *vma = mmap_event->vma;
7381         int executable = vma->vm_flags & VM_EXEC;
7382 
7383         return (!executable && event->attr.mmap_data) ||
7384                (executable && (event->attr.mmap || event->attr.mmap2));
7385 }
7386 
7387 static void perf_event_mmap_output(struct perf_event *event,
7388                                    void *data)
7389 {
7390         struct perf_mmap_event *mmap_event = data;
7391         struct perf_output_handle handle;
7392         struct perf_sample_data sample;
7393         int size = mmap_event->event_id.header.size;
7394         u32 type = mmap_event->event_id.header.type;
7395         int ret;
7396 
7397         if (!perf_event_mmap_match(event, data))
7398                 return;
7399 
7400         if (event->attr.mmap2) {
7401                 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7402                 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7403                 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7404                 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7405                 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7406                 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7407                 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7408         }
7409 
7410         perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7411         ret = perf_output_begin(&handle, event,
7412                                 mmap_event->event_id.header.size);
7413         if (ret)
7414                 goto out;
7415 
7416         mmap_event->event_id.pid = perf_event_pid(event, current);
7417         mmap_event->event_id.tid = perf_event_tid(event, current);
7418 
7419         perf_output_put(&handle, mmap_event->event_id);
7420 
7421         if (event->attr.mmap2) {
7422                 perf_output_put(&handle, mmap_event->maj);
7423                 perf_output_put(&handle, mmap_event->min);
7424                 perf_output_put(&handle, mmap_event->ino);
7425                 perf_output_put(&handle, mmap_event->ino_generation);
7426                 perf_output_put(&handle, mmap_event->prot);
7427                 perf_output_put(&handle, mmap_event->flags);
7428         }
7429 
7430         __output_copy(&handle, mmap_event->file_name,
7431                                    mmap_event->file_size);
7432 
7433         perf_event__output_id_sample(event, &handle, &sample);
7434 
7435         perf_output_end(&handle);
7436 out:
7437         mmap_event->event_id.header.size = size;
7438         mmap_event->event_id.header.type = type;
7439 }
7440 
7441 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7442 {
7443         struct vm_area_struct *vma = mmap_event->vma;
7444         struct file *file = vma->vm_file;
7445         int maj = 0, min = 0;
7446         u64 ino = 0, gen = 0;
7447         u32 prot = 0, flags = 0;
7448         unsigned int size;
7449         char tmp[16];
7450         char *buf = NULL;
7451         char *name;
7452 
7453         if (vma->vm_flags & VM_READ)
7454                 prot |= PROT_READ;
7455         if (vma->vm_flags & VM_WRITE)
7456                 prot |= PROT_WRITE;
7457         if (vma->vm_flags & VM_EXEC)
7458                 prot |= PROT_EXEC;
7459 
7460         if (vma->vm_flags & VM_MAYSHARE)
7461                 flags = MAP_SHARED;
7462         else
7463                 flags = MAP_PRIVATE;
7464 
7465         if (vma->vm_flags & VM_DENYWRITE)
7466                 flags |= MAP_DENYWRITE;
7467         if (vma->vm_flags & VM_MAYEXEC)
7468                 flags |= MAP_EXECUTABLE;
7469         if (vma->vm_flags & VM_LOCKED)
7470                 flags |= MAP_LOCKED;
7471         if (vma->vm_flags & VM_HUGETLB)
7472                 flags |= MAP_HUGETLB;
7473 
7474         if (file) {
7475                 struct inode *inode;
7476                 dev_t dev;
7477 
7478                 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7479                 if (!buf) {
7480                         name = "//enomem";
7481                         goto cpy_name;
7482                 }
7483                 /*
7484                  * d_path() works from the end of the rb backwards, so we
7485                  * need to add enough zero bytes after the string to handle
7486                  * the 64bit alignment we do later.
7487                  */
7488                 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7489                 if (IS_ERR(name)) {
7490                         name = "//toolong";
7491                         goto cpy_name;
7492                 }
7493                 inode = file_inode(vma->vm_file);
7494                 dev = inode->i_sb->s_dev;
7495                 ino = inode->i_ino;
7496                 gen = inode->i_generation;
7497                 maj = MAJOR(dev);
7498                 min = MINOR(dev);
7499 
7500                 goto got_name;
7501         } else {
7502                 if (vma->vm_ops && vma->vm_ops->name) {
7503                         name = (char *) vma->vm_ops->name(vma);
7504                         if (name)
7505                                 goto cpy_name;
7506                 }
7507 
7508                 name = (char *)arch_vma_name(vma);
7509                 if (name)
7510                         goto cpy_name;
7511 
7512                 if (vma->vm_start <= vma->vm_mm->start_brk &&
7513                                 vma->vm_end >= vma->vm_mm->brk) {
7514                         name = "[heap]";
7515                         goto cpy_name;
7516                 }
7517                 if (vma->vm_start <= vma->vm_mm->start_stack &&
7518                                 vma->vm_end >= vma->vm_mm->start_stack) {
7519                         name = "[stack]";
7520                         goto cpy_name;
7521                 }
7522 
7523                 name = "//anon";
7524                 goto cpy_name;
7525         }
7526 
7527 cpy_name:
7528         strlcpy(tmp, name, sizeof(tmp));
7529         name = tmp;
7530 got_name:
7531         /*
7532          * Since our buffer works in 8 byte units we need to align our string
7533          * size to a multiple of 8. However, we must guarantee the tail end is
7534          * zero'd out to avoid leaking random bits to userspace.
7535          */
7536         size = strlen(name)+1;
7537         while (!IS_ALIGNED(size, sizeof(u64)))
7538                 name[size++] = '\0';
7539 
7540         mmap_event->file_name = name;
7541         mmap_event->file_size = size;
7542         mmap_event->maj = maj;
7543         mmap_event->min = min;
7544         mmap_event->ino = ino;
7545         mmap_event->ino_generation = gen;
7546         mmap_event->prot = prot;
7547         mmap_event->flags = flags;
7548 
7549         if (!(vma->vm_flags & VM_EXEC))
7550                 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7551 
7552         mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7553 
7554         perf_iterate_sb(perf_event_mmap_output,
7555                        mmap_event,
7556                        NULL);
7557 
7558         kfree(buf);
7559 }
7560 
7561 /*
7562  * Check whether inode and address range match filter criteria.
7563  */
7564 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7565                                      struct file *file, unsigned long offset,
7566                                      unsigned long size)
7567 {
7568         /* d_inode(NULL) won't be equal to any mapped user-space file */
7569         if (!filter->path.dentry)
7570                 return false;
7571 
7572         if (d_inode(filter->path.dentry) != file_inode(file))
7573                 return false;
7574 
7575         if (filter->offset > offset + size)
7576                 return false;
7577 
7578         if (filter->offset + filter->size < offset)
7579                 return false;
7580 
7581         return true;
7582 }
7583 
7584 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7585                                         struct vm_area_struct *vma,
7586                                         struct perf_addr_filter_range *fr)
7587 {
7588         unsigned long vma_size = vma->vm_end - vma->vm_start;
7589         unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7590         struct file *file = vma->vm_file;
7591 
7592         if (!perf_addr_filter_match(filter, file, off, vma_size))
7593                 return false;
7594 
7595         if (filter->offset < off) {
7596                 fr->start = vma->vm_start;
7597                 fr->size = min(vma_size, filter->size - (off - filter->offset));
7598         } else {
7599                 fr->start = vma->vm_start + filter->offset - off;
7600                 fr->size = min(vma->vm_end - fr->start, filter->size);
7601         }
7602 
7603         return true;
7604 }
7605 
7606 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7607 {
7608         struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7609         struct vm_area_struct *vma = data;
7610         struct perf_addr_filter *filter;
7611         unsigned int restart = 0, count = 0;
7612         unsigned long flags;
7613 
7614         if (!has_addr_filter(event))
7615                 return;
7616 
7617         if (!vma->vm_file)
7618                 return;
7619 
7620         raw_spin_lock_irqsave(&ifh->lock, flags);
7621         list_for_each_entry(filter, &ifh->list, entry) {
7622                 if (perf_addr_filter_vma_adjust(filter, vma,
7623                                                 &event->addr_filter_ranges[count]))
7624                         restart++;
7625 
7626                 count++;
7627         }
7628 
7629         if (restart)
7630                 event->addr_filters_gen++;
7631         raw_spin_unlock_irqrestore(&ifh->lock, flags);
7632 
7633         if (restart)
7634                 perf_event_stop(event, 1);
7635 }
7636 
7637 /*
7638  * Adjust all task's events' filters to the new vma
7639  */
7640 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7641 {
7642         struct perf_event_context *ctx;
7643         int ctxn;
7644 
7645         /*
7646          * Data tracing isn't supported yet and as such there is no need
7647          * to keep track of anything that isn't related to executable code:
7648          */
7649         if (!(vma->vm_flags & VM_EXEC))
7650                 return;
7651 
7652         rcu_read_lock();
7653         for_each_task_context_nr(ctxn) {
7654                 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7655                 if (!ctx)
7656                         continue;
7657 
7658                 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7659         }
7660         rcu_read_unlock();
7661 }
7662 
7663 void perf_event_mmap(struct vm_area_struct *vma)
7664 {
7665         struct perf_mmap_event mmap_event;
7666 
7667         if (!atomic_read(&nr_mmap_events))
7668                 return;
7669 
7670         mmap_event = (struct perf_mmap_event){
7671                 .vma    = vma,
7672                 /* .file_name */
7673                 /* .file_size */
7674                 .event_id  = {
7675                         .header = {
7676                                 .type = PERF_RECORD_MMAP,
7677                                 .misc = PERF_RECORD_MISC_USER,
7678                                 /* .size */
7679                         },
7680                         /* .pid */
7681                         /* .tid */
7682                         .start  = vma->vm_start,
7683                         .len    = vma->vm_end - vma->vm_start,
7684                         .pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
7685                 },
7686                 /* .maj (attr_mmap2 only) */
7687                 /* .min (attr_mmap2 only) */
7688                 /* .ino (attr_mmap2 only) */
7689                 /* .ino_generation (attr_mmap2 only) */
7690                 /* .prot (attr_mmap2 only) */
7691                 /* .flags (attr_mmap2 only) */
7692         };
7693 
7694         perf_addr_filters_adjust(vma);
7695         perf_event_mmap_event(&mmap_event);
7696 }
7697 
7698 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7699                           unsigned long size, u64 flags)
7700 {
7701         struct perf_output_handle handle;
7702         struct perf_sample_data sample;
7703         struct perf_aux_event {
7704                 struct perf_event_header        header;
7705                 u64                             offset;
7706                 u64                             size;
7707                 u64                             flags;
7708         } rec = {
7709                 .header = {
7710                         .type = PERF_RECORD_AUX,
7711                         .misc = 0,
7712                         .size = sizeof(rec),
7713                 },
7714                 .offset         = head,
7715                 .size           = size,
7716                 .flags          = flags,
7717         };
7718         int ret;
7719 
7720         perf_event_header__init_id(&rec.header, &sample, event);
7721         ret = perf_output_begin(&handle, event, rec.header.size);
7722 
7723         if (ret)
7724                 return;
7725 
7726         perf_output_put(&handle, rec);
7727         perf_event__output_id_sample(event, &handle, &sample);
7728 
7729         perf_output_end(&handle);
7730 }
7731 
7732 /*
7733  * Lost/dropped samples logging
7734  */
7735 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7736 {
7737         struct perf_output_handle handle;
7738         struct perf_sample_data sample;
7739         int ret;
7740 
7741         struct {
7742                 struct perf_event_header        header;
7743                 u64                             lost;
7744         } lost_samples_event = {
7745                 .header = {
7746                         .type = PERF_RECORD_LOST_SAMPLES,
7747                         .misc = 0,
7748                         .size = sizeof(lost_samples_event),
7749                 },
7750                 .lost           = lost,
7751         };
7752 
7753         perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7754 
7755         ret = perf_output_begin(&handle, event,
7756                                 lost_samples_event.header.size);
7757         if (ret)
7758                 return;
7759 
7760         perf_output_put(&handle, lost_samples_event);
7761         perf_event__output_id_sample(event, &handle, &sample);
7762         perf_output_end(&handle);
7763 }
7764 
7765 /*
7766  * context_switch tracking
7767  */
7768 
7769 struct perf_switch_event {
7770         struct task_struct      *task;
7771         struct task_struct      *next_prev;
7772 
7773         struct {
7774                 struct perf_event_header        header;
7775                 u32                             next_prev_pid;
7776                 u32                             next_prev_tid;
7777         } event_id;
7778 };
7779 
7780 static int perf_event_switch_match(struct perf_event *event)
7781 {
7782         return event->attr.context_switch;
7783 }
7784 
7785 static void perf_event_switch_output(struct perf_event *event, void *data)
7786 {
7787         struct perf_switch_event *se = data;
7788         struct perf_output_handle handle;
7789         struct perf_sample_data sample;
7790         int ret;
7791 
7792         if (!perf_event_switch_match(event))
7793                 return;
7794 
7795         /* Only CPU-wide events are allowed to see next/prev pid/tid */
7796         if (event->ctx->task) {
7797                 se->event_id.header.type = PERF_RECORD_SWITCH;
7798                 se->event_id.header.size = sizeof(se->event_id.header);
7799         } else {
7800                 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7801                 se->event_id.header.size = sizeof(se->event_id);
7802                 se->event_id.next_prev_pid =
7803                                         perf_event_pid(event, se->next_prev);
7804                 se->event_id.next_prev_tid =
7805                                         perf_event_tid(event, se->next_prev);
7806         }
7807 
7808         perf_event_header__init_id(&se->event_id.header, &sample, event);
7809 
7810         ret = perf_output_begin(&handle, event, se->event_id.header.size);
7811         if (ret)
7812                 return;
7813 
7814         if (event->ctx->task)
7815                 perf_output_put(&handle, se->event_id.header);
7816         else
7817                 perf_output_put(&handle, se->event_id);
7818 
7819         perf_event__output_id_sample(event, &handle, &sample);
7820 
7821         perf_output_end(&handle);
7822 }
7823 
7824 static void perf_event_switch(struct task_struct *task,
7825                               struct task_struct *next_prev, bool sched_in)
7826 {
7827         struct perf_switch_event switch_event;
7828 
7829         /* N.B. caller checks nr_switch_events != 0 */
7830 
7831         switch_event = (struct perf_switch_event){
7832                 .task           = task,
7833                 .next_prev      = next_prev,
7834                 .event_id       = {
7835                         .header = {
7836                                 /* .type */
7837                                 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7838                                 /* .size */
7839                         },
7840                         /* .next_prev_pid */
7841                         /* .next_prev_tid */
7842                 },
7843         };
7844 
7845         if (!sched_in && task->state == TASK_RUNNING)
7846                 switch_event.event_id.header.misc |=
7847                                 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7848 
7849         perf_iterate_sb(perf_event_switch_output,
7850                        &switch_event,
7851                        NULL);
7852 }
7853 
7854 /*
7855  * IRQ throttle logging
7856  */
7857 
7858 static void perf_log_throttle(struct perf_event *event, int enable)
7859 {
7860         struct perf_output_handle handle;
7861         struct perf_sample_data sample;
7862         int ret;
7863 
7864         struct {
7865                 struct perf_event_header        header;
7866                 u64                             time;
7867                 u64                             id;
7868                 u64                             stream_id;
7869         } throttle_event = {
7870                 .header = {
7871                         .type = PERF_RECORD_THROTTLE,
7872                         .misc = 0,
7873                         .size = sizeof(throttle_event),
7874                 },
7875                 .time           = perf_event_clock(event),
7876                 .id             = primary_event_id(event),
7877                 .stream_id      = event->id,
7878         };
7879 
7880         if (enable)
7881                 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7882 
7883         perf_event_header__init_id(&throttle_event.header, &sample, event);
7884 
7885         ret = perf_output_begin(&handle, event,
7886                                 throttle_event.header.size);
7887         if (ret)
7888                 return;
7889 
7890         perf_output_put(&handle, throttle_event);
7891         perf_event__output_id_sample(event, &handle, &sample);
7892         perf_output_end(&handle);
7893 }
7894 
7895 /*
7896  * ksymbol register/unregister tracking
7897  */
7898 
7899 struct perf_ksymbol_event {
7900         const char      *name;
7901         int             name_len;
7902         struct {
7903                 struct perf_event_header        header;
7904                 u64                             addr;
7905                 u32                             len;
7906                 u16                             ksym_type;
7907                 u16                             flags;
7908         } event_id;
7909 };
7910 
7911 static int perf_event_ksymbol_match(struct perf_event *event)
7912 {
7913         return event->attr.ksymbol;
7914 }
7915 
7916 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7917 {
7918         struct perf_ksymbol_event *ksymbol_event = data;
7919         struct perf_output_handle handle;
7920         struct perf_sample_data sample;
7921         int ret;
7922 
7923         if (!perf_event_ksymbol_match(event))
7924                 return;
7925 
7926         perf_event_header__init_id(&ksymbol_event->event_id.header,
7927                                    &sample, event);
7928         ret = perf_output_begin(&handle, event,
7929                                 ksymbol_event->event_id.header.size);
7930         if (ret)
7931                 return;
7932 
7933         perf_output_put(&handle, ksymbol_event->event_id);
7934         __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7935         perf_event__output_id_sample(event, &handle, &sample);
7936 
7937         perf_output_end(&handle);
7938 }
7939 
7940 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7941                         const char *sym)
7942 {
7943         struct perf_ksymbol_event ksymbol_event;
7944         char name[KSYM_NAME_LEN];
7945         u16 flags = 0;
7946         int name_len;
7947 
7948         if (!atomic_read(&nr_ksymbol_events))
7949                 return;
7950 
7951         if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7952             ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7953                 goto err;
7954 
7955         strlcpy(name, sym, KSYM_NAME_LEN);
7956         name_len = strlen(name) + 1;
7957         while (!IS_ALIGNED(name_len, sizeof(u64)))
7958                 name[name_len++] = '\0';
7959         BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7960 
7961         if (unregister)
7962                 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7963 
7964         ksymbol_event = (struct perf_ksymbol_event){
7965                 .name = name,
7966                 .name_len = name_len,
7967                 .event_id = {
7968                         .header = {
7969                                 .type = PERF_RECORD_KSYMBOL,
7970                                 .size = sizeof(ksymbol_event.event_id) +
7971                                         name_len,
7972                         },
7973                         .addr = addr,
7974                         .len = len,
7975                         .ksym_type = ksym_type,
7976                         .flags = flags,
7977                 },
7978         };
7979 
7980         perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7981         return;
7982 err:
7983         WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7984 }
7985 
7986 /*
7987  * bpf program load/unload tracking
7988  */
7989 
7990 struct perf_bpf_event {
7991         struct bpf_prog *prog;
7992         struct {
7993                 struct perf_event_header        header;
7994                 u16                             type;
7995                 u16                             flags;
7996                 u32                             id;
7997                 u8                              tag[BPF_TAG_SIZE];
7998         } event_id;
7999 };
8000 
8001 static int perf_event_bpf_match(struct perf_event *event)
8002 {
8003         return event->attr.bpf_event;
8004 }
8005 
8006 static void perf_event_bpf_output(struct perf_event *event, void *data)
8007 {
8008         struct perf_bpf_event *bpf_event = data;
8009         struct perf_output_handle handle;
8010         struct perf_sample_data sample;
8011         int ret;
8012 
8013         if (!perf_event_bpf_match(event))
8014                 return;
8015 
8016         perf_event_header__init_id(&bpf_event->event_id.header,
8017                                    &sample, event);
8018         ret = perf_output_begin(&handle, event,
8019                                 bpf_event->event_id.header.size);
8020         if (ret)
8021                 return;
8022 
8023         perf_output_put(&handle, bpf_event->event_id);
8024         perf_event__output_id_sample(event, &handle, &sample);
8025 
8026         perf_output_end(&handle);
8027 }
8028 
8029 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8030                                          enum perf_bpf_event_type type)
8031 {
8032         bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8033         char sym[KSYM_NAME_LEN];
8034         int i;
8035 
8036         if (prog->aux->func_cnt == 0) {
8037                 bpf_get_prog_name(prog, sym);
8038                 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8039                                    (u64)(unsigned long)prog->bpf_func,
8040                                    prog->jited_len, unregister, sym);
8041         } else {
8042                 for (i = 0; i < prog->aux->func_cnt; i++) {
8043                         struct bpf_prog *subprog = prog->aux->func[i];
8044 
8045                         bpf_get_prog_name(subprog, sym);
8046                         perf_event_ksymbol(
8047                                 PERF_RECORD_KSYMBOL_TYPE_BPF,
8048                                 (u64)(unsigned long)subprog->bpf_func,
8049                                 subprog->jited_len, unregister, sym);
8050                 }
8051         }
8052 }
8053 
8054 void perf_event_bpf_event(struct bpf_prog *prog,
8055                           enum perf_bpf_event_type type,
8056                           u16 flags)
8057 {
8058         struct perf_bpf_event bpf_event;
8059 
8060         if (type <= PERF_BPF_EVENT_UNKNOWN ||
8061             type >= PERF_BPF_EVENT_MAX)
8062                 return;
8063 
8064         switch (type) {
8065         case PERF_BPF_EVENT_PROG_LOAD:
8066         case PERF_BPF_EVENT_PROG_UNLOAD:
8067                 if (atomic_read(&nr_ksymbol_events))
8068                         perf_event_bpf_emit_ksymbols(prog, type);
8069                 break;
8070         default:
8071                 break;
8072         }
8073 
8074         if (!atomic_read(&nr_bpf_events))
8075                 return;
8076 
8077         bpf_event = (struct perf_bpf_event){
8078                 .prog = prog,
8079                 .event_id = {
8080                         .header = {
8081                                 .type = PERF_RECORD_BPF_EVENT,
8082                                 .size = sizeof(bpf_event.event_id),
8083                         },
8084                         .type = type,
8085                         .flags = flags,
8086                         .id = prog->aux->id,
8087                 },
8088         };
8089 
8090         BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8091 
8092         memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8093         perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8094 }
8095 
8096 void perf_event_itrace_started(struct perf_event *event)
8097 {
8098         event->attach_state |= PERF_ATTACH_ITRACE;
8099 }
8100 
8101 static void perf_log_itrace_start(struct perf_event *event)
8102 {
8103         struct perf_output_handle handle;
8104         struct perf_sample_data sample;
8105         struct perf_aux_event {
8106                 struct perf_event_header        header;
8107                 u32                             pid;
8108                 u32                             tid;
8109         } rec;
8110         int ret;
8111 
8112         if (event->parent)
8113                 event = event->parent;
8114 
8115         if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8116             event->attach_state & PERF_ATTACH_ITRACE)
8117                 return;
8118 
8119         rec.header.type = PERF_RECORD_ITRACE_START;
8120         rec.header.misc = 0;
8121         rec.header.size = sizeof(rec);
8122         rec.pid = perf_event_pid(event, current);
8123         rec.tid = perf_event_tid(event, current);
8124 
8125         perf_event_header__init_id(&rec.header, &sample, event);
8126         ret = perf_output_begin(&handle, event, rec.header.size);
8127 
8128         if (ret)
8129                 return;
8130 
8131         perf_output_put(&handle, rec);
8132         perf_event__output_id_sample(event, &handle, &sample);
8133 
8134         perf_output_end(&handle);
8135 }
8136 
8137 static int
8138 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8139 {
8140         struct hw_perf_event *hwc = &event->hw;
8141         int ret = 0;
8142         u64 seq;
8143 
8144         seq = __this_cpu_read(perf_throttled_seq);
8145         if (seq != hwc->interrupts_seq) {
8146                 hwc->interrupts_seq = seq;
8147                 hwc->interrupts = 1;
8148         } else {
8149                 hwc->interrupts++;
8150                 if (unlikely(throttle
8151                              && hwc->interrupts >= max_samples_per_tick)) {
8152                         __this_cpu_inc(perf_throttled_count);
8153                         tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8154                         hwc->interrupts = MAX_INTERRUPTS;
8155                         perf_log_throttle(event, 0);
8156                         ret = 1;
8157                 }
8158         }
8159 
8160         if (event->attr.freq) {
8161                 u64 now = perf_clock();
8162                 s64 delta = now - hwc->freq_time_stamp;
8163 
8164                 hwc->freq_time_stamp = now;
8165 
8166                 if (delta > 0 && delta < 2*TICK_NSEC)
8167                         perf_adjust_period(event, delta, hwc->last_period, true);
8168         }
8169 
8170         return ret;
8171 }
8172 
8173 int perf_event_account_interrupt(struct perf_event *event)
8174 {
8175         return __perf_event_account_interrupt(event, 1);
8176 }
8177 
8178 /*
8179  * Generic event overflow handling, sampling.
8180  */
8181 
8182 static int __perf_event_overflow(struct perf_event *event,
8183                                    int throttle, struct perf_sample_data *data,
8184                                    struct pt_regs *regs)
8185 {
8186         int events = atomic_read(&event->event_limit);
8187         int ret = 0;
8188 
8189         /*
8190          * Non-sampling counters might still use the PMI to fold short
8191          * hardware counters, ignore those.
8192          */
8193         if (unlikely(!is_sampling_event(event)))
8194                 return 0;
8195 
8196         ret = __perf_event_account_interrupt(event, throttle);
8197 
8198         /*
8199          * XXX event_limit might not quite work as expected on inherited
8200          * events
8201          */
8202 
8203         event->pending_kill = POLL_IN;
8204         if (events && atomic_dec_and_test(&event->event_limit)) {
8205                 ret = 1;
8206                 event->pending_kill = POLL_HUP;
8207 
8208                 perf_event_disable_inatomic(event);
8209         }
8210 
8211         READ_ONCE(event->overflow_handler)(event, data, regs);
8212 
8213         if (*perf_event_fasync(event) && event->pending_kill) {
8214                 event->pending_wakeup = 1;
8215                 irq_work_queue(&event->pending);
8216         }
8217 
8218         return ret;
8219 }
8220 
8221 int perf_event_overflow(struct perf_event *event,
8222                           struct perf_sample_data *data,
8223                           struct pt_regs *regs)
8224 {
8225         return __perf_event_overflow(event, 1, data, regs);
8226 }
8227 
8228 /*
8229  * Generic software event infrastructure
8230  */
8231 
8232 struct swevent_htable {
8233         struct swevent_hlist            *swevent_hlist;
8234         struct mutex                    hlist_mutex;
8235         int                             hlist_refcount;
8236 
8237         /* Recursion avoidance in each contexts */
8238         int                             recursion[PERF_NR_CONTEXTS];
8239 };
8240 
8241 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8242 
8243 /*
8244  * We directly increment event->count and keep a second value in
8245  * event->hw.period_left to count intervals. This period event
8246  * is kept in the range [-sample_period, 0] so that we can use the
8247  * sign as trigger.
8248  */
8249 
8250 u64 perf_swevent_set_period(struct perf_event *event)
8251 {
8252         struct hw_perf_event *hwc = &event->hw;
8253         u64 period = hwc->last_period;
8254         u64 nr, offset;
8255         s64 old, val;
8256 
8257         hwc->last_period = hwc->sample_period;
8258 
8259 again:
8260         old = val = local64_read(&hwc->period_left);
8261         if (val < 0)
8262                 return 0;
8263 
8264         nr = div64_u64(period + val, period);
8265         offset = nr * period;
8266         val -= offset;
8267         if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8268                 goto again;
8269 
8270         return nr;
8271 }
8272 
8273 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8274                                     struct perf_sample_data *data,
8275                                     struct pt_regs *regs)
8276 {
8277         struct hw_perf_event *hwc = &event->hw;
8278         int throttle = 0;
8279 
8280         if (!overflow)
8281                 overflow = perf_swevent_set_period(event);
8282 
8283         if (hwc->interrupts == MAX_INTERRUPTS)
8284                 return;
8285 
8286         for (; overflow; overflow--) {
8287                 if (__perf_event_overflow(event, throttle,
8288                                             data, regs)) {
8289                         /*
8290                          * We inhibit the overflow from happening when
8291                          * hwc->interrupts == MAX_INTERRUPTS.
8292                          */
8293                         break;
8294                 }
8295                 throttle = 1;
8296         }
8297 }
8298 
8299 static void perf_swevent_event(struct perf_event *event, u64 nr,
8300                                struct perf_sample_data *data,
8301                                struct pt_regs *regs)
8302 {
8303         struct hw_perf_event *hwc = &event->hw;
8304 
8305         local64_add(nr, &event->count);
8306 
8307         if (!regs)
8308                 return;
8309 
8310         if (!is_sampling_event(event))
8311                 return;
8312 
8313         if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8314                 data->period = nr;
8315                 return perf_swevent_overflow(event, 1, data, regs);
8316         } else
8317                 data->period = event->hw.last_period;
8318 
8319         if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8320                 return perf_swevent_overflow(event, 1, data, regs);
8321 
8322         if (local64_add_negative(nr, &hwc->period_left))
8323                 return;
8324 
8325         perf_swevent_overflow(event, 0, data, regs);
8326 }
8327 
8328 static int perf_exclude_event(struct perf_event *event,
8329                               struct pt_regs *regs)
8330 {
8331         if (event->hw.state & PERF_HES_STOPPED)
8332                 return 1;
8333 
8334         if (regs) {
8335                 if (event->attr.exclude_user && user_mode(regs))
8336                         return 1;
8337 
8338                 if (event->attr.exclude_kernel && !user_mode(regs))
8339                         return 1;
8340         }
8341 
8342         return 0;
8343 }
8344 
8345 static int perf_swevent_match(struct perf_event *event,
8346                                 enum perf_type_id type,
8347                                 u32 event_id,
8348                                 struct perf_sample_data *data,
8349                                 struct pt_regs *regs)
8350 {
8351         if (event->attr.type != type)
8352                 return 0;
8353 
8354         if (event->attr.config != event_id)
8355                 return 0;
8356 
8357         if (perf_exclude_event(event, regs))
8358                 return 0;
8359 
8360         return 1;
8361 }
8362 
8363 static inline u64 swevent_hash(u64 type, u32 event_id)
8364 {
8365         u64 val = event_id | (type << 32);
8366 
8367         return hash_64(val, SWEVENT_HLIST_BITS);
8368 }
8369 
8370 static inline struct hlist_head *
8371 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8372 {
8373         u64 hash = swevent_hash(type, event_id);
8374 
8375         return &hlist->heads[hash];
8376 }
8377 
8378 /* For the read side: events when they trigger */
8379 static inline struct hlist_head *
8380 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8381 {
8382         struct swevent_hlist *hlist;
8383 
8384         hlist = rcu_dereference(swhash->swevent_hlist);
8385         if (!hlist)
8386                 return NULL;
8387 
8388         return __find_swevent_head(hlist, type, event_id);
8389 }
8390 
8391 /* For the event head insertion and removal in the hlist */
8392 static inline struct hlist_head *
8393 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8394 {
8395         struct swevent_hlist *hlist;
8396         u32 event_id = event->attr.config;
8397         u64 type = event->attr.type;
8398 
8399         /*
8400          * Event scheduling is always serialized against hlist allocation
8401          * and release. Which makes the protected version suitable here.
8402          * The context lock guarantees that.
8403          */
8404         hlist = rcu_dereference_protected(swhash->swevent_hlist,
8405                                           lockdep_is_held(&event->ctx->lock));
8406         if (!hlist)
8407                 return NULL;
8408 
8409         return __find_swevent_head(hlist, type, event_id);
8410 }
8411 
8412 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8413                                     u64 nr,
8414                                     struct perf_sample_data *data,
8415                                     struct pt_regs *regs)
8416 {
8417         struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8418         struct perf_event *event;
8419         struct hlist_head *head;
8420 
8421         rcu_read_lock();
8422         head = find_swevent_head_rcu(swhash, type, event_id);
8423         if (!head)
8424                 goto end;
8425 
8426         hlist_for_each_entry_rcu(event, head, hlist_entry) {
8427                 if (perf_swevent_match(event, type, event_id, data, regs))
8428                         perf_swevent_event(event, nr, data, regs);
8429         }
8430 end:
8431         rcu_read_unlock();
8432 }
8433 
8434 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8435 
8436 int perf_swevent_get_recursion_context(void)
8437 {
8438         struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8439 
8440         return get_recursion_context(swhash->recursion);
8441 }
8442 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8443 
8444 void perf_swevent_put_recursion_context(int rctx)
8445 {
8446         struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8447 
8448         put_recursion_context(swhash->recursion, rctx);
8449 }
8450 
8451 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8452 {
8453         struct perf_sample_data data;
8454 
8455         if (WARN_ON_ONCE(!regs))
8456                 return;
8457 
8458         perf_sample_data_init(&data, addr, 0);
8459         do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8460 }
8461 
8462 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8463 {
8464         int rctx;
8465 
8466         preempt_disable_notrace();
8467         rctx = perf_swevent_get_recursion_context();
8468         if (unlikely(rctx < 0))
8469                 goto fail;
8470 
8471         ___perf_sw_event(event_id, nr, regs, addr);
8472 
8473         perf_swevent_put_recursion_context(rctx);
8474 fail:
8475         preempt_enable_notrace();
8476 }
8477 
8478 static void perf_swevent_read(struct perf_event *event)
8479 {
8480 }
8481 
8482 static int perf_swevent_add(struct perf_event *event, int flags)
8483 {
8484         struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8485         struct hw_perf_event *hwc = &event->hw;
8486         struct hlist_head *head;
8487 
8488         if (is_sampling_event(event)) {
8489                 hwc->last_period = hwc->sample_period;
8490                 perf_swevent_set_period(event);
8491         }
8492 
8493         hwc->state = !(flags & PERF_EF_START);
8494 
8495         head = find_swevent_head(swhash, event);
8496         if (WARN_ON_ONCE(!head))
8497                 return -EINVAL;
8498 
8499         hlist_add_head_rcu(&event->hlist_entry, head);
8500         perf_event_update_userpage(event);
8501 
8502         return 0;
8503 }
8504 
8505 static void perf_swevent_del(struct perf_event *event, int flags)
8506 {
8507         hlist_del_rcu(&event->hlist_entry);
8508 }
8509 
8510 static void perf_swevent_start(struct perf_event *event, int flags)
8511 {
8512         event->hw.state = 0;
8513 }
8514 
8515 static void perf_swevent_stop(struct perf_event *event, int flags)
8516 {
8517         event->hw.state = PERF_HES_STOPPED;
8518 }
8519 
8520 /* Deref the hlist from the update side */
8521 static inline struct swevent_hlist *
8522 swevent_hlist_deref(struct swevent_htable *swhash)
8523 {
8524         return rcu_dereference_protected(swhash->swevent_hlist,
8525                                          lockdep_is_held(&swhash->hlist_mutex));
8526 }
8527 
8528 static void swevent_hlist_release(struct swevent_htable *swhash)
8529 {
8530         struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8531 
8532         if (!hlist)
8533                 return;
8534 
8535         RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8536         kfree_rcu(hlist, rcu_head);
8537 }
8538 
8539 static void swevent_hlist_put_cpu(int cpu)
8540 {
8541         struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8542 
8543         mutex_lock(&swhash->hlist_mutex);
8544 
8545         if (!--swhash->hlist_refcount)
8546                 swevent_hlist_release(swhash);
8547 
8548         mutex_unlock(&swhash->hlist_mutex);
8549 }
8550 
8551 static void swevent_hlist_put(void)
8552 {
8553         int cpu;
8554 
8555         for_each_possible_cpu(cpu)
8556                 swevent_hlist_put_cpu(cpu);
8557 }
8558 
8559 static int swevent_hlist_get_cpu(int cpu)
8560 {
8561         struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8562         int err = 0;
8563 
8564         mutex_lock(&swhash->hlist_mutex);
8565         if (!swevent_hlist_deref(swhash) &&
8566             cpumask_test_cpu(cpu, perf_online_mask)) {
8567                 struct swevent_hlist *hlist;
8568 
8569                 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8570                 if (!hlist) {
8571                         err = -ENOMEM;
8572                         goto exit;
8573                 }
8574                 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8575         }
8576         swhash->hlist_refcount++;
8577 exit:
8578         mutex_unlock(&swhash->hlist_mutex);
8579 
8580         return err;
8581 }
8582 
8583 static int swevent_hlist_get(void)
8584 {
8585         int err, cpu, failed_cpu;
8586 
8587         mutex_lock(&pmus_lock);
8588         for_each_possible_cpu(cpu) {
8589                 err = swevent_hlist_get_cpu(cpu);
8590                 if (err) {
8591                         failed_cpu = cpu;
8592                         goto fail;
8593                 }
8594         }
8595         mutex_unlock(&pmus_lock);
8596         return 0;
8597 fail:
8598         for_each_possible_cpu(cpu) {
8599                 if (cpu == failed_cpu)
8600                         break;
8601                 swevent_hlist_put_cpu(cpu);
8602         }
8603         mutex_unlock(&pmus_lock);
8604         return err;
8605 }
8606 
8607 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8608 
8609 static void sw_perf_event_destroy(struct perf_event *event)
8610 {
8611         u64 event_id = event->attr.config;
8612 
8613         WARN_ON(event->parent);
8614 
8615         static_key_slow_dec(&perf_swevent_enabled[event_id]);
8616         swevent_hlist_put();
8617 }
8618 
8619 static int perf_swevent_init(struct perf_event *event)
8620 {
8621         u64 event_id = event->attr.config;
8622 
8623         if (event->attr.type != PERF_TYPE_SOFTWARE)
8624                 return -ENOENT;
8625 
8626         /*
8627          * no branch sampling for software events
8628          */
8629         if (has_branch_stack(event))
8630                 return -EOPNOTSUPP;
8631 
8632         switch (event_id) {
8633         case PERF_COUNT_SW_CPU_CLOCK:
8634         case PERF_COUNT_SW_TASK_CLOCK:
8635                 return -ENOENT;
8636 
8637         default:
8638                 break;
8639         }
8640 
8641         if (event_id >= PERF_COUNT_SW_MAX)
8642                 return -ENOENT;
8643 
8644         if (!event->parent) {
8645                 int err;
8646 
8647                 err = swevent_hlist_get();
8648                 if (err)
8649                         return err;
8650 
8651                 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8652                 event->destroy = sw_perf_event_destroy;
8653         }
8654 
8655         return 0;
8656 }
8657 
8658 static struct pmu perf_swevent = {
8659         .task_ctx_nr    = perf_sw_context,
8660 
8661         .capabilities   = PERF_PMU_CAP_NO_NMI,
8662 
8663         .event_init     = perf_swevent_init,
8664         .add            = perf_swevent_add,
8665         .del            = perf_swevent_del,
8666         .start          = perf_swevent_start,
8667         .stop           = perf_swevent_stop,
8668         .read           = perf_swevent_read,
8669 };
8670 
8671 #ifdef CONFIG_EVENT_TRACING
8672 
8673 static int perf_tp_filter_match(struct perf_event *event,
8674                                 struct perf_sample_data *data)
8675 {
8676         void *record = data->raw->frag.data;
8677 
8678         /* only top level events have filters set */
8679         if (event->parent)
8680                 event = event->parent;
8681 
8682         if (likely(!event->filter) || filter_match_preds(event->filter, record))
8683                 return 1;
8684         return 0;
8685 }
8686 
8687 static int perf_tp_event_match(struct perf_event *event,
8688                                 struct perf_sample_data *data,
8689                                 struct pt_regs *regs)
8690 {
8691         if (event->hw.state & PERF_HES_STOPPED)
8692                 return 0;
8693         /*
8694          * If exclude_kernel, only trace user-space tracepoints (uprobes)
8695          */
8696         if (event->attr.exclude_kernel && !user_mode(regs))
8697                 return 0;
8698 
8699         if (!perf_tp_filter_match(event, data))
8700                 return 0;
8701 
8702         return 1;
8703 }
8704 
8705 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8706                                struct trace_event_call *call, u64 count,
8707                                struct pt_regs *regs, struct hlist_head *head,
8708                                struct task_struct *task)
8709 {
8710         if (bpf_prog_array_valid(call)) {
8711                 *(struct pt_regs **)raw_data = regs;
8712                 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8713                         perf_swevent_put_recursion_context(rctx);
8714                         return;
8715                 }
8716         }
8717         perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8718                       rctx, task);
8719 }
8720 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8721 
8722 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8723                    struct pt_regs *regs, struct hlist_head *head, int rctx,
8724                    struct task_struct *task)
8725 {
8726         struct perf_sample_data data;
8727         struct perf_event *event;
8728 
8729         struct perf_raw_record raw = {
8730                 .frag = {
8731                         .size = entry_size,
8732                         .data = record,
8733                 },
8734         };
8735 
8736         perf_sample_data_init(&data, 0, 0);
8737         data.raw = &raw;
8738 
8739         perf_trace_buf_update(record, event_type);
8740 
8741         hlist_for_each_entry_rcu(event, head, hlist_entry) {
8742                 if (perf_tp_event_match(event, &data, regs))
8743                         perf_swevent_event(event, count, &data, regs);
8744         }
8745 
8746         /*
8747          * If we got specified a target task, also iterate its context and
8748          * deliver this event there too.
8749          */
8750         if (task && task != current) {
8751                 struct perf_event_context *ctx;
8752                 struct trace_entry *entry = record;
8753 
8754                 rcu_read_lock();
8755                 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8756                 if (!ctx)
8757                         goto unlock;
8758 
8759                 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8760                         if (event->cpu != smp_processor_id())
8761                                 continue;
8762                         if (event->attr.type != PERF_TYPE_TRACEPOINT)
8763                                 continue;
8764                         if (event->attr.config != entry->type)
8765                                 continue;
8766                         if (perf_tp_event_match(event, &data, regs))
8767                                 perf_swevent_event(event, count, &data, regs);
8768                 }
8769 unlock:
8770                 rcu_read_unlock();
8771         }
8772 
8773         perf_swevent_put_recursion_context(rctx);
8774 }
8775 EXPORT_SYMBOL_GPL(perf_tp_event);
8776 
8777 static void tp_perf_event_destroy(struct perf_event *event)
8778 {
8779         perf_trace_destroy(event);
8780 }
8781 
8782 static int perf_tp_event_init(struct perf_event *event)
8783 {
8784         int err;
8785 
8786         if (event->attr.type != PERF_TYPE_TRACEPOINT)
8787                 return -ENOENT;
8788 
8789         /*
8790          * no branch sampling for tracepoint events
8791          */
8792         if (has_branch_stack(event))
8793                 return -EOPNOTSUPP;
8794 
8795         err = perf_trace_init(event);
8796         if (err)
8797                 return err;
8798 
8799         event->destroy = tp_perf_event_destroy;
8800 
8801         return 0;
8802 }
8803 
8804 static struct pmu perf_tracepoint = {
8805         .task_ctx_nr    = perf_sw_context,
8806 
8807         .event_init     = perf_tp_event_init,
8808         .add            = perf_trace_add,
8809         .del            = perf_trace_del,
8810         .start          = perf_swevent_start,
8811         .stop           = perf_swevent_stop,
8812         .read           = perf_swevent_read,
8813 };
8814 
8815 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8816 /*
8817  * Flags in config, used by dynamic PMU kprobe and uprobe
8818  * The flags should match following PMU_FORMAT_ATTR().
8819  *
8820  * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8821  *                               if not set, create kprobe/uprobe
8822  *
8823  * The following values specify a reference counter (or semaphore in the
8824  * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8825  * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8826  *
8827  * PERF_UPROBE_REF_CTR_OFFSET_BITS      # of bits in config as th offset
8828  * PERF_UPROBE_REF_CTR_OFFSET_SHIFT     # of bits to shift left
8829  */
8830 enum perf_probe_config {
8831         PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0,  /* [k,u]retprobe */
8832         PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8833         PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8834 };
8835 
8836 PMU_FORMAT_ATTR(retprobe, "config:0");
8837 #endif
8838 
8839 #ifdef CONFIG_KPROBE_EVENTS
8840 static struct attribute *kprobe_attrs[] = {
8841         &format_attr_retprobe.attr,
8842         NULL,
8843 };
8844 
8845 static struct attribute_group kprobe_format_group = {
8846         .name = "format",
8847         .attrs = kprobe_attrs,
8848 };
8849 
8850 static const struct attribute_group *kprobe_attr_groups[] = {
8851         &kprobe_format_group,
8852         NULL,
8853 };
8854 
8855 static int perf_kprobe_event_init(struct perf_event *event);
8856 static struct pmu perf_kprobe = {
8857         .task_ctx_nr    = perf_sw_context,
8858         .event_init     = perf_kprobe_event_init,
8859         .add            = perf_trace_add,
8860         .del            = perf_trace_del,
8861         .start          = perf_swevent_start,
8862         .stop           = perf_swevent_stop,
8863         .read           = perf_swevent_read,
8864         .attr_groups    = kprobe_attr_groups,
8865 };
8866 
8867 static int perf_kprobe_event_init(struct perf_event *event)
8868 {
8869         int err;
8870         bool is_retprobe;
8871 
8872         if (event->attr.type != perf_kprobe.type)
8873                 return -ENOENT;
8874 
8875         if (!capable(CAP_SYS_ADMIN))
8876                 return -EACCES;
8877 
8878         /*
8879          * no branch sampling for probe events
8880          */
8881         if (has_branch_stack(event))
8882                 return -EOPNOTSUPP;
8883 
8884         is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8885         err = perf_kprobe_init(event, is_retprobe);
8886         if (err)
8887                 return err;
8888 
8889         event->destroy = perf_kprobe_destroy;
8890 
8891         return 0;
8892 }
8893 #endif /* CONFIG_KPROBE_EVENTS */
8894 
8895 #ifdef CONFIG_UPROBE_EVENTS
8896 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8897 
8898 static struct attribute *uprobe_attrs[] = {
8899         &format_attr_retprobe.attr,
8900         &format_attr_ref_ctr_offset.attr,
8901         NULL,
8902 };
8903 
8904 static struct attribute_group uprobe_format_group = {
8905         .name = "format",
8906         .attrs = uprobe_attrs,
8907 };
8908 
8909 static const struct attribute_group *uprobe_attr_groups[] = {
8910         &uprobe_format_group,
8911         NULL,
8912 };
8913 
8914 static int perf_uprobe_event_init(struct perf_event *event);
8915 static struct pmu perf_uprobe = {
8916         .task_ctx_nr    = perf_sw_context,
8917         .event_init     = perf_uprobe_event_init,
8918         .add            = perf_trace_add,
8919         .del            = perf_trace_del,
8920         .start          = perf_swevent_start,
8921         .stop           = perf_swevent_stop,
8922         .read           = perf_swevent_read,
8923         .attr_groups    = uprobe_attr_groups,
8924 };
8925 
8926 static int perf_uprobe_event_init(struct perf_event *event)
8927 {
8928         int err;
8929         unsigned long ref_ctr_offset;
8930         bool is_retprobe;
8931 
8932         if (event->attr.type != perf_uprobe.type)
8933                 return -ENOENT;
8934 
8935         if (!capable(CAP_SYS_ADMIN))
8936                 return -EACCES;
8937 
8938         /*
8939          * no branch sampling for probe events
8940          */
8941         if (has_branch_stack(event))
8942                 return -EOPNOTSUPP;
8943 
8944         is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8945         ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8946         err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8947         if (err)
8948                 return err;
8949 
8950         event->destroy = perf_uprobe_destroy;
8951 
8952         return 0;
8953 }
8954 #endif /* CONFIG_UPROBE_EVENTS */
8955 
8956 static inline void perf_tp_register(void)
8957 {
8958         perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8959 #ifdef CONFIG_KPROBE_EVENTS
8960         perf_pmu_register(&perf_kprobe, "kprobe", -1);
8961 #endif
8962 #ifdef CONFIG_UPROBE_EVENTS
8963         perf_pmu_register(&perf_uprobe, "uprobe", -1);
8964 #endif
8965 }
8966 
8967 static void perf_event_free_filter(struct perf_event *event)
8968 {
8969         ftrace_profile_free_filter(event);
8970 }
8971 
8972 #ifdef CONFIG_BPF_SYSCALL
8973 static void bpf_overflow_handler(struct perf_event *event,
8974                                  struct perf_sample_data *data,
8975                                  struct pt_regs *regs)
8976 {
8977         struct bpf_perf_event_data_kern ctx = {
8978                 .data = data,
8979                 .event = event,
8980         };
8981         int ret = 0;
8982 
8983         ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8984         preempt_disable();
8985         if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8986                 goto out;
8987         rcu_read_lock();
8988         ret = BPF_PROG_RUN(event->prog, &ctx);
8989         rcu_read_unlock();
8990 out:
8991         __this_cpu_dec(bpf_prog_active);
8992         preempt_enable();
8993         if (!ret)
8994                 return;
8995 
8996         event->orig_overflow_handler(event, data, regs);
8997 }
8998 
8999 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9000 {
9001         struct bpf_prog *prog;
9002 
9003         if (event->overflow_handler_context)
9004                 /* hw breakpoint or kernel counter */
9005                 return -EINVAL;
9006 
9007         if (event->prog)
9008                 return -EEXIST;
9009 
9010         prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9011         if (IS_ERR(prog))
9012                 return PTR_ERR(prog);
9013 
9014         event->prog = prog;
9015         event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9016         WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9017         return 0;
9018 }
9019 
9020 static void perf_event_free_bpf_handler(struct perf_event *event)
9021 {
9022         struct bpf_prog *prog = event->prog;
9023 
9024         if (!prog)
9025                 return;
9026 
9027         WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9028         event->prog = NULL;
9029         bpf_prog_put(prog);
9030 }
9031 #else
9032 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9033 {
9034         return -EOPNOTSUPP;
9035 }
9036 static void perf_event_free_bpf_handler(struct perf_event *event)
9037 {
9038 }
9039 #endif
9040 
9041 /*
9042  * returns true if the event is a tracepoint, or a kprobe/upprobe created
9043  * with perf_event_open()
9044  */
9045 static inline bool perf_event_is_tracing(struct perf_event *event)
9046 {
9047         if (event->pmu == &perf_tracepoint)
9048                 return true;
9049 #ifdef CONFIG_KPROBE_EVENTS
9050         if (event->pmu == &perf_kprobe)
9051                 return true;
9052 #endif
9053 #ifdef CONFIG_UPROBE_EVENTS
9054         if (event->pmu == &perf_uprobe)
9055                 return true;
9056 #endif
9057         return false;
9058 }
9059 
9060 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9061 {
9062         bool is_kprobe, is_tracepoint, is_syscall_tp;
9063         struct bpf_prog *prog;
9064         int ret;
9065 
9066         if (!perf_event_is_tracing(event))
9067                 return perf_event_set_bpf_handler(event, prog_fd);
9068 
9069         is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9070         is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9071         is_syscall_tp = is_syscall_trace_event(event->tp_event);
9072         if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9073                 /* bpf programs can only be attached to u/kprobe or tracepoint */
9074                 return -EINVAL;
9075 
9076         prog = bpf_prog_get(prog_fd);
9077         if (IS_ERR(prog))
9078                 return PTR_ERR(prog);
9079 
9080         if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9081             (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9082             (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9083                 /* valid fd, but invalid bpf program type */
9084                 bpf_prog_put(prog);
9085                 return -EINVAL;
9086         }
9087 
9088         /* Kprobe override only works for kprobes, not uprobes. */
9089         if (prog->kprobe_override &&
9090             !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9091                 bpf_prog_put(prog);
9092                 return -EINVAL;
9093         }
9094 
9095         if (is_tracepoint || is_syscall_tp) {
9096                 int off = trace_event_get_offsets(event->tp_event);
9097 
9098                 if (prog->aux->max_ctx_offset > off) {
9099                         bpf_prog_put(prog);
9100                         return -EACCES;
9101                 }
9102         }
9103 
9104         ret = perf_event_attach_bpf_prog(event, prog);
9105         if (ret)
9106                 bpf_prog_put(prog);
9107         return ret;
9108 }
9109 
9110 static void perf_event_free_bpf_prog(struct perf_event *event)
9111 {
9112         if (!perf_event_is_tracing(event)) {
9113                 perf_event_free_bpf_handler(event);
9114                 return;
9115         }
9116         perf_event_detach_bpf_prog(event);
9117 }
9118 
9119 #else
9120 
9121 static inline void perf_tp_register(void)
9122 {
9123 }
9124 
9125 static void perf_event_free_filter(struct perf_event *event)
9126 {
9127 }
9128 
9129 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9130 {
9131         return -ENOENT;
9132 }
9133 
9134 static void perf_event_free_bpf_prog(struct perf_event *event)
9135 {
9136 }
9137 #endif /* CONFIG_EVENT_TRACING */
9138 
9139 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9140 void perf_bp_event(struct perf_event *bp, void *data)
9141 {
9142         struct perf_sample_data sample;
9143         struct pt_regs *regs = data;
9144 
9145         perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9146 
9147         if (!bp->hw.state && !perf_exclude_event(bp, regs))
9148                 perf_swevent_event(bp, 1, &sample, regs);
9149 }
9150 #endif
9151 
9152 /*
9153  * Allocate a new address filter
9154  */
9155 static struct perf_addr_filter *
9156 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9157 {
9158         int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9159         struct perf_addr_filter *filter;
9160 
9161         filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9162         if (!filter)
9163                 return NULL;
9164 
9165         INIT_LIST_HEAD(&filter->entry);
9166         list_add_tail(&filter->entry, filters);
9167 
9168         return filter;
9169 }
9170 
9171 static void free_filters_list(struct list_head *filters)
9172 {
9173         struct perf_addr_filter *filter, *iter;
9174 
9175         list_for_each_entry_safe(filter, iter, filters, entry) {
9176                 path_put(&filter->path);
9177                 list_del(&filter->entry);
9178                 kfree(filter);
9179         }
9180 }
9181 
9182 /*
9183  * Free existing address filters and optionally install new ones
9184  */
9185 static void perf_addr_filters_splice(struct perf_event *event,
9186                                      struct list_head *head)
9187 {
9188         unsigned long flags;
9189         LIST_HEAD(list);
9190 
9191         if (!has_addr_filter(event))
9192                 return;
9193 
9194         /* don't bother with children, they don't have their own filters */
9195         if (event->parent)
9196                 return;
9197 
9198         raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9199 
9200         list_splice_init(&event->addr_filters.list, &list);
9201         if (head)
9202                 list_splice(head, &event->addr_filters.list);
9203 
9204         raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9205 
9206         free_filters_list(&list);
9207 }
9208 
9209 /*
9210  * Scan through mm's vmas and see if one of them matches the
9211  * @filter; if so, adjust filter's address range.
9212  * Called with mm::mmap_sem down for reading.
9213  */
9214 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9215                                    struct mm_struct *mm,
9216                                    struct perf_addr_filter_range *fr)
9217 {
9218         struct vm_area_struct *vma;
9219 
9220         for (vma = mm->mmap; vma; vma = vma->vm_next) {
9221                 if (!vma->vm_file)
9222                         continue;
9223 
9224                 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9225                         return;
9226         }
9227 }
9228 
9229 /*
9230  * Update event's address range filters based on the
9231  * task's existing mappings, if any.
9232  */
9233 static void perf_event_addr_filters_apply(struct perf_event *event)
9234 {
9235         struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9236         struct task_struct *task = READ_ONCE(event->ctx->task);
9237         struct perf_addr_filter *filter;
9238         struct mm_struct *mm = NULL;
9239         unsigned int count = 0;
9240         unsigned long flags;
9241 
9242         /*
9243          * We may observe TASK_TOMBSTONE, which means that the event tear-down
9244          * will stop on the parent's child_mutex that our caller is also holding
9245          */
9246         if (task == TASK_TOMBSTONE)
9247                 return;
9248 
9249         if (ifh->nr_file_filters) {
9250                 mm = get_task_mm(event->ctx->task);
9251                 if (!mm)
9252                         goto restart;
9253 
9254                 down_read(&mm->mmap_sem);
9255         }
9256 
9257         raw_spin_lock_irqsave(&ifh->lock, flags);
9258         list_for_each_entry(filter, &ifh->list, entry) {
9259                 if (filter->path.dentry) {
9260                         /*
9261                          * Adjust base offset if the filter is associated to a
9262                          * binary that needs to be mapped:
9263                          */
9264                         event->addr_filter_ranges[count].start = 0;
9265                         event->addr_filter_ranges[count].size = 0;
9266 
9267                         perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9268                 } else {
9269                         event->addr_filter_ranges[count].start = filter->offset;
9270                         event->addr_filter_ranges[count].size  = filter->size;
9271                 }
9272 
9273                 count++;
9274         }
9275 
9276         event->addr_filters_gen++;
9277         raw_spin_unlock_irqrestore(&ifh->lock, flags);
9278 
9279         if (ifh->nr_file_filters) {
9280                 up_read(&mm->mmap_sem);
9281 
9282                 mmput(mm);
9283         }
9284 
9285 restart:
9286         perf_event_stop(event, 1);
9287 }
9288 
9289 /*
9290  * Address range filtering: limiting the data to certain
9291  * instruction address ranges. Filters are ioctl()ed to us from
9292  * userspace as ascii strings.
9293  *
9294  * Filter string format:
9295  *
9296  * ACTION RANGE_SPEC
9297  * where ACTION is one of the
9298  *  * "filter": limit the trace to this region
9299  *  * "start": start tracing from this address
9300  *  * "stop": stop tracing at this address/region;
9301  * RANGE_SPEC is
9302  *  * for kernel addresses: <start address>[/<size>]
9303  *  * for object files:     <start address>[/<size>]@</path/to/object/file>
9304  *
9305  * if <size> is not specified or is zero, the range is treated as a single
9306  * address; not valid for ACTION=="filter".
9307  */
9308 enum {
9309         IF_ACT_NONE = -1,
9310         IF_ACT_FILTER,
9311         IF_ACT_START,
9312         IF_ACT_STOP,
9313         IF_SRC_FILE,
9314         IF_SRC_KERNEL,
9315         IF_SRC_FILEADDR,
9316         IF_SRC_KERNELADDR,
9317 };
9318 
9319 enum {
9320         IF_STATE_ACTION = 0,
9321         IF_STATE_SOURCE,
9322         IF_STATE_END,
9323 };
9324 
9325 static const match_table_t if_tokens = {
9326         { IF_ACT_FILTER,        "filter" },
9327         { IF_ACT_START,         "start" },
9328         { IF_ACT_STOP,          "stop" },
9329         { IF_SRC_FILE,          "%u/%u@%s" },
9330         { IF_SRC_KERNEL,        "%u/%u" },
9331         { IF_SRC_FILEADDR,      "%u@%s" },
9332         { IF_SRC_KERNELADDR,    "%u" },
9333         { IF_ACT_NONE,          NULL },
9334 };
9335 
9336 /*
9337  * Address filter string parser
9338  */
9339 static int
9340 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9341                              struct list_head *filters)
9342 {
9343         struct perf_addr_filter *filter = NULL;
9344         char *start, *orig, *filename = NULL;
9345         substring_t args[MAX_OPT_ARGS];
9346         int state = IF_STATE_ACTION, token;
9347         unsigned int kernel = 0;
9348         int ret = -EINVAL;
9349 
9350         orig = fstr = kstrdup(fstr, GFP_KERNEL);
9351         if (!fstr)
9352                 return -ENOMEM;
9353 
9354         while ((start = strsep(&fstr, " ,\n")) != NULL) {
9355                 static const enum perf_addr_filter_action_t actions[] = {
9356                         [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9357                         [IF_ACT_START]  = PERF_ADDR_FILTER_ACTION_START,
9358                         [IF_ACT_STOP]   = PERF_ADDR_FILTER_ACTION_STOP,
9359                 };
9360                 ret = -EINVAL;
9361 
9362                 if (!*start)
9363                         continue;
9364 
9365                 /* filter definition begins */
9366                 if (state == IF_STATE_ACTION) {
9367                         filter = perf_addr_filter_new(event, filters);
9368                         if (!filter)
9369                                 goto fail;
9370                 }
9371 
9372                 token = match_token(start, if_tokens, args);
9373                 switch (token) {
9374                 case IF_ACT_FILTER:
9375                 case IF_ACT_START:
9376                 case IF_ACT_STOP:
9377                         if (state != IF_STATE_ACTION)
9378                                 goto fail;
9379 
9380                         filter->action = actions[token];
9381                         state = IF_STATE_SOURCE;
9382                         break;
9383 
9384                 case IF_SRC_KERNELADDR:
9385                 case IF_SRC_KERNEL:
9386                         kernel = 1;
9387                         /* fall through */
9388 
9389                 case IF_SRC_FILEADDR:
9390                 case IF_SRC_FILE:
9391                         if (state != IF_STATE_SOURCE)
9392                                 goto fail;
9393 
9394                         *args[0].to = 0;
9395                         ret = kstrtoul(args[0].from, 0, &filter->offset);
9396                         if (ret)
9397                                 goto fail;
9398 
9399                         if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9400                                 *args[1].to = 0;
9401                                 ret = kstrtoul(args[1].from, 0, &filter->size);
9402                                 if (ret)
9403                                         goto fail;
9404                         }
9405 
9406                         if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9407                                 int fpos = token == IF_SRC_FILE ? 2 : 1;
9408 
9409                                 filename = match_strdup(&args[fpos]);
9410                                 if (!filename) {
9411                                         ret = -ENOMEM;
9412                                         goto fail;
9413                                 }
9414                         }
9415 
9416                         state = IF_STATE_END;
9417                         break;
9418 
9419                 default:
9420                         goto fail;
9421                 }
9422 
9423                 /*
9424                  * Filter definition is fully parsed, validate and install it.
9425                  * Make sure that it doesn't contradict itself or the event's
9426                  * attribute.
9427                  */
9428                 if (state == IF_STATE_END) {
9429                         ret = -EINVAL;
9430                         if (kernel && event->attr.exclude_kernel)
9431                                 goto fail;
9432 
9433                         /*
9434                          * ACTION "filter" must have a non-zero length region
9435                          * specified.
9436                          */
9437                         if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9438                             !filter->size)
9439                                 goto fail;
9440 
9441                         if (!kernel) {
9442                                 if (!filename)
9443                                         goto fail;
9444 
9445                                 /*
9446                                  * For now, we only support file-based filters
9447                                  * in per-task events; doing so for CPU-wide
9448                                  * events requires additional context switching
9449                                  * trickery, since same object code will be
9450                                  * mapped at different virtual addresses in
9451                                  * different processes.
9452                                  */
9453                                 ret = -EOPNOTSUPP;
9454                                 if (!event->ctx->task)
9455                                         goto fail_free_name;
9456 
9457                                 /* look up the path and grab its inode */
9458                                 ret = kern_path(filename, LOOKUP_FOLLOW,
9459                                                 &filter->path);
9460                                 if (ret)
9461                                         goto fail_free_name;
9462 
9463                                 kfree(filename);
9464                                 filename = NULL;
9465 
9466                                 ret = -EINVAL;
9467                                 if (!filter->path.dentry ||
9468                                     !S_ISREG(d_inode(filter->path.dentry)
9469                                              ->i_mode))
9470                                         goto fail;
9471 
9472                                 event->addr_filters.nr_file_filters++;
9473                         }
9474 
9475                         /* ready to consume more filters */
9476                         state = IF_STATE_ACTION;
9477                         filter = NULL;
9478                 }
9479         }
9480 
9481         if (state != IF_STATE_ACTION)
9482                 goto fail;
9483 
9484         kfree(orig);
9485 
9486         return 0;
9487 
9488 fail_free_name:
9489         kfree(filename);
9490 fail:
9491         free_filters_list(filters);
9492         kfree(orig);
9493 
9494         return ret;
9495 }
9496 
9497 static int
9498 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9499 {
9500         LIST_HEAD(filters);
9501         int ret;
9502 
9503         /*
9504          * Since this is called in perf_ioctl() path, we're already holding
9505          * ctx::mutex.
9506          */
9507         lockdep_assert_held(&event->ctx->mutex);
9508 
9509         if (WARN_ON_ONCE(event->parent))
9510                 return -EINVAL;
9511 
9512         ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9513         if (ret)
9514                 goto fail_clear_files;
9515 
9516         ret = event->pmu->addr_filters_validate(&filters);
9517         if (ret)
9518                 goto fail_free_filters;
9519 
9520         /* remove existing filters, if any */
9521         perf_addr_filters_splice(event, &filters);
9522 
9523         /* install new filters */
9524         perf_event_for_each_child(event, perf_event_addr_filters_apply);
9525 
9526         return ret;
9527 
9528 fail_free_filters:
9529         free_filters_list(&filters);
9530 
9531 fail_clear_files:
9532         event->addr_filters.nr_file_filters = 0;
9533 
9534         return ret;
9535 }
9536 
9537 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9538 {
9539         int ret = -EINVAL;
9540         char *filter_str;
9541 
9542         filter_str = strndup_user(arg, PAGE_SIZE);
9543         if (IS_ERR(filter_str))
9544                 return PTR_ERR(filter_str);
9545 
9546 #ifdef CONFIG_EVENT_TRACING
9547         if (perf_event_is_tracing(event)) {
9548                 struct perf_event_context *ctx = event->ctx;
9549 
9550                 /*
9551                  * Beware, here be dragons!!
9552                  *
9553                  * the tracepoint muck will deadlock against ctx->mutex, but
9554                  * the tracepoint stuff does not actually need it. So
9555                  * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9556                  * already have a reference on ctx.
9557                  *
9558                  * This can result in event getting moved to a different ctx,
9559                  * but that does not affect the tracepoint state.
9560                  */
9561                 mutex_unlock(&ctx->mutex);
9562                 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9563                 mutex_lock(&ctx->mutex);
9564         } else
9565 #endif
9566         if (has_addr_filter(event))
9567                 ret = perf_event_set_addr_filter(event, filter_str);
9568 
9569         kfree(filter_str);
9570         return ret;
9571 }
9572 
9573 /*
9574  * hrtimer based swevent callback
9575  */
9576 
9577 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9578 {
9579         enum hrtimer_restart ret = HRTIMER_RESTART;
9580         struct perf_sample_data data;
9581         struct pt_regs *regs;
9582         struct perf_event *event;
9583         u64 period;
9584 
9585         event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9586 
9587         if (event->state != PERF_EVENT_STATE_ACTIVE)
9588                 return HRTIMER_NORESTART;
9589 
9590         event->pmu->read(event);
9591 
9592         perf_sample_data_init(&data, 0, event->hw.last_period);
9593         regs = get_irq_regs();
9594 
9595         if (regs && !perf_exclude_event(event, regs)) {
9596                 if (!(event->attr.exclude_idle && is_idle_task(current)))
9597                         if (__perf_event_overflow(event, 1, &data, regs))
9598                                 ret = HRTIMER_NORESTART;
9599         }
9600 
9601         period = max_t(u64, 10000, event->hw.sample_period);
9602         hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9603 
9604         return ret;
9605 }
9606 
9607 static void perf_swevent_start_hrtimer(struct perf_event *event)
9608 {
9609         struct hw_perf_event *hwc = &event->hw;
9610         s64 period;
9611 
9612         if (!is_sampling_event(event))
9613                 return;
9614 
9615         period = local64_read(&hwc->period_left);
9616         if (period) {
9617                 if (period < 0)
9618                         period = 10000;
9619 
9620                 local64_set(&hwc->period_left, 0);
9621         } else {
9622                 period = max_t(u64, 10000, hwc->sample_period);
9623         }
9624         hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9625                       HRTIMER_MODE_REL_PINNED_HARD);
9626 }
9627 
9628 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9629 {
9630         struct hw_perf_event *hwc = &event->hw;
9631 
9632         if (is_sampling_event(event)) {
9633                 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9634                 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9635 
9636                 hrtimer_cancel(&hwc->hrtimer);
9637         }
9638 }
9639 
9640 static void perf_swevent_init_hrtimer(struct perf_event *event)
9641 {
9642         struct hw_perf_event *hwc = &event->hw;
9643 
9644         if (!is_sampling_event(event))
9645                 return;
9646 
9647         hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
9648         hwc->hrtimer.function = perf_swevent_hrtimer;
9649 
9650         /*
9651          * Since hrtimers have a fixed rate, we can do a static freq->period
9652          * mapping and avoid the whole period adjust feedback stuff.
9653          */
9654         if (event->attr.freq) {
9655                 long freq = event->attr.sample_freq;
9656 
9657                 event->attr.sample_period = NSEC_PER_SEC / freq;
9658                 hwc->sample_period = event->attr.sample_period;
9659                 local64_set(&hwc->period_left, hwc->sample_period);
9660                 hwc->last_period = hwc->sample_period;
9661                 event->attr.freq = 0;
9662         }
9663 }
9664 
9665 /*
9666  * Software event: cpu wall time clock
9667  */
9668 
9669 static void cpu_clock_event_update(struct perf_event *event)
9670 {
9671         s64 prev;
9672         u64 now;
9673 
9674         now = local_clock();
9675         prev = local64_xchg(&event->hw.prev_count, now);
9676         local64_add(now - prev, &event->count);
9677 }
9678 
9679 static void cpu_clock_event_start(struct perf_event *event, int flags)
9680 {
9681         local64_set(&event->hw.prev_count, local_clock());
9682         perf_swevent_start_hrtimer(event);
9683 }
9684 
9685 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9686 {
9687         perf_swevent_cancel_hrtimer(event);
9688         cpu_clock_event_update(event);
9689 }
9690 
9691 static int cpu_clock_event_add(struct perf_event *event, int flags)
9692 {
9693         if (flags & PERF_EF_START)
9694                 cpu_clock_event_start(event, flags);
9695         perf_event_update_userpage(event);
9696 
9697         return 0;
9698 }
9699 
9700 static void cpu_clock_event_del(struct perf_event *event, int flags)
9701 {
9702         cpu_clock_event_stop(event, flags);
9703 }
9704 
9705 static void cpu_clock_event_read(struct perf_event *event)
9706 {
9707         cpu_clock_event_update(event);
9708 }
9709 
9710 static int cpu_clock_event_init(struct perf_event *event)
9711 {
9712         if (event->attr.type != PERF_TYPE_SOFTWARE)
9713                 return -ENOENT;
9714 
9715         if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9716                 return -ENOENT;
9717 
9718         /*
9719          * no branch sampling for software events
9720          */
9721         if (has_branch_stack(event))
9722                 return -EOPNOTSUPP;
9723 
9724         perf_swevent_init_hrtimer(event);
9725 
9726         return 0;
9727 }
9728 
9729 static struct pmu perf_cpu_clock = {
9730         .task_ctx_nr    = perf_sw_context,
9731 
9732         .capabilities   = PERF_PMU_CAP_NO_NMI,
9733 
9734         .event_init     = cpu_clock_event_init,
9735         .add            = cpu_clock_event_add,
9736         .del            = cpu_clock_event_del,
9737         .start          = cpu_clock_event_start,
9738         .stop           = cpu_clock_event_stop,
9739         .read           = cpu_clock_event_read,
9740 };
9741 
9742 /*
9743  * Software event: task time clock
9744  */
9745 
9746 static void task_clock_event_update(struct perf_event *event, u64 now)
9747 {
9748         u64 prev;
9749         s64 delta;
9750 
9751         prev = local64_xchg(&event->hw.prev_count, now);
9752         delta = now - prev;
9753         local64_add(delta, &event->count);
9754 }
9755 
9756 static void task_clock_event_start(struct perf_event *event, int flags)
9757 {
9758         local64_set(&event->hw.prev_count, event->ctx->time);
9759         perf_swevent_start_hrtimer(event);
9760 }
9761 
9762 static void task_clock_event_stop(struct perf_event *event, int flags)
9763 {
9764         perf_swevent_cancel_hrtimer(event);
9765         task_clock_event_update(event, event->ctx->time);
9766 }
9767 
9768 static int task_clock_event_add(struct perf_event *event, int flags)
9769 {
9770         if (flags & PERF_EF_START)
9771                 task_clock_event_start(event, flags);
9772         perf_event_update_userpage(event);
9773 
9774         return 0;
9775 }
9776 
9777 static void task_clock_event_del(struct perf_event *event, int flags)
9778 {
9779         task_clock_event_stop(event, PERF_EF_UPDATE);
9780 }
9781 
9782 static void task_clock_event_read(struct perf_event *event)
9783 {
9784         u64 now = perf_clock();
9785         u64 delta = now - event->ctx->timestamp;
9786         u64 time = event->ctx->time + delta;
9787 
9788         task_clock_event_update(event, time);
9789 }
9790 
9791 static int task_clock_event_init(struct perf_event *event)
9792 {
9793         if (event->attr.type != PERF_TYPE_SOFTWARE)
9794                 return -ENOENT;
9795 
9796         if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9797                 return -ENOENT;
9798 
9799         /*
9800          * no branch sampling for software events
9801          */
9802         if (has_branch_stack(event))
9803                 return -EOPNOTSUPP;
9804 
9805         perf_swevent_init_hrtimer(event);
9806 
9807         return 0;
9808 }
9809 
9810 static struct pmu perf_task_clock = {
9811         .task_ctx_nr    = perf_sw_context,
9812 
9813         .capabilities   = PERF_PMU_CAP_NO_NMI,
9814 
9815         .event_init     = task_clock_event_init,
9816         .add            = task_clock_event_add,
9817         .del            = task_clock_event_del,
9818         .start          = task_clock_event_start,
9819         .stop           = task_clock_event_stop,
9820         .read           = task_clock_event_read,
9821 };
9822 
9823 static void perf_pmu_nop_void(struct pmu *pmu)
9824 {
9825 }
9826 
9827 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9828 {
9829 }
9830 
9831 static int perf_pmu_nop_int(struct pmu *pmu)
9832 {
9833         return 0;
9834 }
9835 
9836 static int perf_event_nop_int(struct perf_event *event, u64 value)
9837 {
9838         return 0;
9839 }
9840 
9841 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9842 
9843 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9844 {
9845         __this_cpu_write(nop_txn_flags, flags);
9846 
9847         if (flags & ~PERF_PMU_TXN_ADD)
9848                 return;
9849 
9850         perf_pmu_disable(pmu);
9851 }
9852 
9853 static int perf_pmu_commit_txn(struct pmu *pmu)
9854 {
9855         unsigned int flags = __this_cpu_read(nop_txn_flags);
9856 
9857         __this_cpu_write(nop_txn_flags, 0);
9858 
9859         if (flags & ~PERF_PMU_TXN_ADD)
9860                 return 0;
9861 
9862         perf_pmu_enable(pmu);
9863         return 0;
9864 }
9865 
9866 static void perf_pmu_cancel_txn(struct pmu *pmu)
9867 {
9868         unsigned int flags =  __this_cpu_read(nop_txn_flags);
9869 
9870         __this_cpu_write(nop_txn_flags, 0);
9871 
9872         if (flags & ~PERF_PMU_TXN_ADD)
9873                 return;
9874 
9875         perf_pmu_enable(pmu);
9876 }
9877 
9878 static int perf_event_idx_default(struct perf_event *event)
9879 {
9880         return 0;
9881 }
9882 
9883 /*
9884  * Ensures all contexts with the same task_ctx_nr have the same
9885  * pmu_cpu_context too.
9886  */
9887 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9888 {
9889         struct pmu *pmu;
9890 
9891         if (ctxn < 0)
9892                 return NULL;
9893 
9894         list_for_each_entry(pmu, &pmus, entry) {
9895                 if (pmu->task_ctx_nr == ctxn)
9896                         return pmu->pmu_cpu_context;
9897         }
9898 
9899         return NULL;
9900 }
9901 
9902 static void free_pmu_context(struct pmu *pmu)
9903 {
9904         /*
9905          * Static contexts such as perf_sw_context have a global lifetime
9906          * and may be shared between different PMUs. Avoid freeing them
9907          * when a single PMU is going away.
9908          */
9909         if (pmu->task_ctx_nr > perf_invalid_context)
9910                 return;
9911 
9912         free_percpu(pmu->pmu_cpu_context);
9913 }
9914 
9915 /*
9916  * Let userspace know that this PMU supports address range filtering:
9917  */
9918 static ssize_t nr_addr_filters_show(struct device *dev,
9919                                     struct device_attribute *attr,
9920                                     char *page)
9921 {
9922         struct pmu *pmu = dev_get_drvdata(dev);
9923 
9924         return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9925 }
9926 DEVICE_ATTR_RO(nr_addr_filters);
9927 
9928 static struct idr pmu_idr;
9929 
9930 static ssize_t
9931 type_show(struct device *dev, struct device_attribute *attr, char *page)
9932 {
9933         struct pmu *pmu = dev_get_drvdata(dev);
9934 
9935         return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9936 }
9937 static DEVICE_ATTR_RO(type);
9938 
9939 static ssize_t
9940 perf_event_mux_interval_ms_show(struct device *dev,
9941                                 struct device_attribute *attr,
9942                                 char *page)
9943 {
9944         struct pmu *pmu = dev_get_drvdata(dev);
9945 
9946         return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9947 }
9948 
9949 static DEFINE_MUTEX(mux_interval_mutex);
9950 
9951 static ssize_t
9952 perf_event_mux_interval_ms_store(struct device *dev,
9953                                  struct device_attribute *attr,
9954                                  const char *buf, size_t count)
9955 {
9956         struct pmu *pmu = dev_get_drvdata(dev);
9957         int timer, cpu, ret;
9958 
9959         ret = kstrtoint(buf, 0, &timer);
9960         if (ret)
9961                 return ret;
9962 
9963         if (timer < 1)
9964                 return -EINVAL;
9965 
9966         /* same value, noting to do */
9967         if (timer == pmu->hrtimer_interval_ms)
9968                 return count;
9969 
9970         mutex_lock(&mux_interval_mutex);
9971         pmu->hrtimer_interval_ms = timer;
9972 
9973         /* update all cpuctx for this PMU */
9974         cpus_read_lock();
9975         for_each_online_cpu(cpu) {
9976                 struct perf_cpu_context *cpuctx;
9977                 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9978                 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9979 
9980                 cpu_function_call(cpu,
9981                         (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9982         }
9983         cpus_read_unlock();
9984         mutex_unlock(&mux_interval_mutex);
9985 
9986         return count;
9987 }
9988 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9989 
9990 static struct attribute *pmu_dev_attrs[] = {
9991         &dev_attr_type.attr,
9992         &dev_attr_perf_event_mux_interval_ms.attr,
9993         NULL,
9994 };
9995 ATTRIBUTE_GROUPS(pmu_dev);
9996 
9997 static int pmu_bus_running;
9998 static struct bus_type pmu_bus = {
9999         .name           = "event_source",
10000         .dev_groups     = pmu_dev_groups,
10001 };
10002 
10003 static void pmu_dev_release(struct device *dev)
10004 {
10005         kfree(dev);
10006 }
10007 
10008 static int pmu_dev_alloc(struct pmu *pmu)
10009 {
10010         int ret = -ENOMEM;
10011 
10012         pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10013         if (!pmu->dev)
10014                 goto out;
10015 
10016         pmu->dev->groups = pmu->attr_groups;
10017         device_initialize(pmu->dev);
10018         ret = dev_set_name(pmu->dev, "%s", pmu->name);
10019         if (ret)
10020                 goto free_dev;
10021 
10022         dev_set_drvdata(pmu->dev, pmu);
10023         pmu->dev->bus = &pmu_bus;
10024         pmu->dev->release = pmu_dev_release;
10025         ret = device_add(pmu->dev);
10026         if (ret)
10027                 goto free_dev;
10028 
10029         /* For PMUs with address filters, throw in an extra attribute: */
10030         if (pmu->nr_addr_filters)
10031                 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10032 
10033         if (ret)
10034                 goto del_dev;
10035 
10036         if (pmu->attr_update)
10037                 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10038 
10039         if (ret)
10040                 goto del_dev;
10041 
10042 out:
10043         return ret;
10044 
10045 del_dev:
10046         device_del(pmu->dev);
10047 
10048 free_dev:
10049         put_device(pmu->dev);
10050         goto out;
10051 }
10052 
10053 static struct lock_class_key cpuctx_mutex;
10054 static struct lock_class_key cpuctx_lock;
10055 
10056 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10057 {
10058         int cpu, ret;
10059 
10060         mutex_lock(&pmus_lock);
10061         ret = -ENOMEM;
10062         pmu->pmu_disable_count = alloc_percpu(int);
10063         if (!pmu->pmu_disable_count)
10064                 goto unlock;
10065 
10066         pmu->type = -1;
10067         if (!name)
10068                 goto skip_type;
10069         pmu->name = name;
10070 
10071         if (type < 0) {
10072                 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
10073                 if (type < 0) {
10074                         ret = type;
10075                         goto free_pdc;
10076                 }
10077         }
10078         pmu->type = type;
10079 
10080         if (pmu_bus_running) {
10081                 ret = pmu_dev_alloc(pmu);
10082                 if (ret)
10083                         goto free_idr;
10084         }
10085 
10086 skip_type:
10087         if (pmu->task_ctx_nr == perf_hw_context) {
10088                 static int hw_context_taken = 0;
10089 
10090                 /*
10091                  * Other than systems with heterogeneous CPUs, it never makes
10092                  * sense for two PMUs to share perf_hw_context. PMUs which are
10093                  * uncore must use perf_invalid_context.
10094                  */
10095                 if (WARN_ON_ONCE(hw_context_taken &&
10096                     !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10097                         pmu->task_ctx_nr = perf_invalid_context;
10098 
10099                 hw_context_taken = 1;
10100         }
10101 
10102         pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10103         if (pmu->pmu_cpu_context)
10104                 goto got_cpu_context;
10105 
10106         ret = -ENOMEM;
10107         pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10108         if (!pmu->pmu_cpu_context)
10109                 goto free_dev;
10110 
10111         for_each_possible_cpu(cpu) {
10112                 struct perf_cpu_context *cpuctx;
10113 
10114                 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10115                 __perf_event_init_context(&cpuctx->ctx);
10116                 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10117                 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10118                 cpuctx->ctx.pmu = pmu;
10119                 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10120 
10121                 __perf_mux_hrtimer_init(cpuctx, cpu);
10122         }
10123 
10124 got_cpu_context:
10125         if (!pmu->start_txn) {
10126                 if (pmu->pmu_enable) {
10127                         /*
10128                          * If we have pmu_enable/pmu_disable calls, install
10129                          * transaction stubs that use that to try and batch
10130                          * hardware accesses.
10131                          */
10132                         pmu->start_txn  = perf_pmu_start_txn;
10133                         pmu->commit_txn = perf_pmu_commit_txn;
10134                         pmu->cancel_txn = perf_pmu_cancel_txn;
10135                 } else {
10136                         pmu->start_txn  = perf_pmu_nop_txn;
10137                         pmu->commit_txn = perf_pmu_nop_int;
10138                         pmu->cancel_txn = perf_pmu_nop_void;
10139                 }
10140         }
10141 
10142         if (!pmu->pmu_enable) {
10143                 pmu->pmu_enable  = perf_pmu_nop_void;
10144                 pmu->pmu_disable = perf_pmu_nop_void;
10145         }
10146 
10147         if (!pmu->check_period)
10148                 pmu->check_period = perf_event_nop_int;
10149 
10150         if (!pmu->event_idx)
10151                 pmu->event_idx = perf_event_idx_default;
10152 
10153         list_add_rcu(&pmu->entry, &pmus);
10154         atomic_set(&pmu->exclusive_cnt, 0);
10155         ret = 0;
10156 unlock:
10157         mutex_unlock(&pmus_lock);
10158 
10159         return ret;
10160 
10161 free_dev:
10162         device_del(pmu->dev);
10163         put_device(pmu->dev);
10164 
10165 free_idr:
10166         if (pmu->type >= PERF_TYPE_MAX)
10167                 idr_remove(&pmu_idr, pmu->type);
10168 
10169 free_pdc:
10170         free_percpu(pmu->pmu_disable_count);
10171         goto unlock;
10172 }
10173 EXPORT_SYMBOL_GPL(perf_pmu_register);
10174 
10175 void perf_pmu_unregister(struct pmu *pmu)
10176 {
10177         mutex_lock(&pmus_lock);
10178         list_del_rcu(&pmu->entry);
10179 
10180         /*
10181          * We dereference the pmu list under both SRCU and regular RCU, so
10182          * synchronize against both of those.
10183          */
10184         synchronize_srcu(&pmus_srcu);
10185         synchronize_rcu();
10186 
10187         free_percpu(pmu->pmu_disable_count);
10188         if (pmu->type >= PERF_TYPE_MAX)
10189                 idr_remove(&pmu_idr, pmu->type);
10190         if (pmu_bus_running) {
10191                 if (pmu->nr_addr_filters)
10192                         device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10193                 device_del(pmu->dev);
10194                 put_device(pmu->dev);
10195         }
10196         free_pmu_context(pmu);
10197         mutex_unlock(&pmus_lock);
10198 }
10199 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10200 
10201 static inline bool has_extended_regs(struct perf_event *event)
10202 {
10203         return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10204                (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10205 }
10206 
10207 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10208 {
10209         struct perf_event_context *ctx = NULL;
10210         int ret;
10211 
10212         if (!try_module_get(pmu->module))
10213                 return -ENODEV;
10214 
10215         /*
10216          * A number of pmu->event_init() methods iterate the sibling_list to,
10217          * for example, validate if the group fits on the PMU. Therefore,
10218          * if this is a sibling event, acquire the ctx->mutex to protect
10219          * the sibling_list.
10220          */
10221         if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10222                 /*
10223                  * This ctx->mutex can nest when we're called through
10224                  * inheritance. See the perf_event_ctx_lock_nested() comment.
10225                  */
10226                 ctx = perf_event_ctx_lock_nested(event->group_leader,
10227                                                  SINGLE_DEPTH_NESTING);
10228                 BUG_ON(!ctx);
10229         }
10230 
10231         event->pmu = pmu;
10232         ret = pmu->event_init(event);
10233 
10234         if (ctx)
10235                 perf_event_ctx_unlock(event->group_leader, ctx);
10236 
10237         if (!ret) {
10238                 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10239                     has_extended_regs(event))
10240                         ret = -EOPNOTSUPP;
10241 
10242                 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10243                     event_has_any_exclude_flag(event))
10244                         ret = -EINVAL;
10245 
10246                 if (ret && event->destroy)
10247                         event->destroy(event);
10248         }
10249 
10250         if (ret)
10251                 module_put(pmu->module);
10252 
10253         return ret;
10254 }
10255 
10256 static struct pmu *perf_init_event(struct perf_event *event)
10257 {
10258         struct pmu *pmu;
10259         int idx;
10260         int ret;
10261 
10262         idx = srcu_read_lock(&pmus_srcu);
10263 
10264         /* Try parent's PMU first: */
10265         if (event->parent && event->parent->pmu) {
10266                 pmu = event->parent->pmu;
10267                 ret = perf_try_init_event(pmu, event);
10268                 if (!ret)
10269                         goto unlock;
10270         }
10271 
10272         rcu_read_lock();
10273         pmu = idr_find(&pmu_idr, event->attr.type);
10274         rcu_read_unlock();
10275         if (pmu) {
10276                 ret = perf_try_init_event(pmu, event);
10277                 if (ret)
10278                         pmu = ERR_PTR(ret);
10279                 goto unlock;
10280         }
10281 
10282         list_for_each_entry_rcu(pmu, &pmus, entry) {
10283                 ret = perf_try_init_event(pmu, event);
10284                 if (!ret)
10285                         goto unlock;
10286 
10287                 if (ret != -ENOENT) {
10288                         pmu = ERR_PTR(ret);
10289                         goto unlock;
10290                 }
10291         }
10292         pmu = ERR_PTR(-ENOENT);
10293 unlock:
10294         srcu_read_unlock(&pmus_srcu, idx);
10295 
10296         return pmu;
10297 }
10298 
10299 static void attach_sb_event(struct perf_event *event)
10300 {
10301         struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10302 
10303         raw_spin_lock(&pel->lock);
10304         list_add_rcu(&event->sb_list, &pel->list);
10305         raw_spin_unlock(&pel->lock);
10306 }
10307 
10308 /*
10309  * We keep a list of all !task (and therefore per-cpu) events
10310  * that need to receive side-band records.
10311  *
10312  * This avoids having to scan all the various PMU per-cpu contexts
10313  * looking for them.
10314  */
10315 static void account_pmu_sb_event(struct perf_event *event)
10316 {
10317         if (is_sb_event(event))
10318                 attach_sb_event(event);
10319 }
10320 
10321 static void account_event_cpu(struct perf_event *event, int cpu)
10322 {
10323         if (event->parent)
10324                 return;
10325 
10326         if (is_cgroup_event(event))
10327                 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10328 }
10329 
10330 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10331 static void account_freq_event_nohz(void)
10332 {
10333 #ifdef CONFIG_NO_HZ_FULL
10334         /* Lock so we don't race with concurrent unaccount */
10335         spin_lock(&nr_freq_lock);
10336         if (atomic_inc_return(&nr_freq_events) == 1)
10337                 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10338         spin_unlock(&nr_freq_lock);
10339 #endif
10340 }
10341 
10342 static void account_freq_event(void)
10343 {
10344         if (tick_nohz_full_enabled())
10345                 account_freq_event_nohz();
10346         else
10347                 atomic_inc(&nr_freq_events);
10348 }
10349 
10350 
10351 static void account_event(struct perf_event *event)
10352 {
10353         bool inc = false;
10354 
10355         if (event->parent)
10356                 return;
10357 
10358         if (event->attach_state & PERF_ATTACH_TASK)
10359                 inc = true;
10360         if (event->attr.mmap || event->attr.mmap_data)
10361                 atomic_inc(&nr_mmap_events);
10362         if (event->attr.comm)
10363                 atomic_inc(&nr_comm_events);
10364         if (event->attr.namespaces)
10365                 atomic_inc(&nr_namespaces_events);
10366         if (event->attr.task)
10367                 atomic_inc(&nr_task_events);
10368         if (event->attr.freq)
10369                 account_freq_event();
10370         if (event->attr.context_switch) {
10371                 atomic_inc(&nr_switch_events);
10372                 inc = true;
10373         }
10374         if (has_branch_stack(event))
10375                 inc = true;
10376         if (is_cgroup_event(event))
10377                 inc = true;
10378         if (event->attr.ksymbol)
10379                 atomic_inc(&nr_ksymbol_events);
10380         if (event->attr.bpf_event)
10381                 atomic_inc(&nr_bpf_events);
10382 
10383         if (inc) {
10384                 /*
10385                  * We need the mutex here because static_branch_enable()
10386                  * must complete *before* the perf_sched_count increment
10387                  * becomes visible.
10388                  */
10389                 if (atomic_inc_not_zero(&perf_sched_count))
10390                         goto enabled;
10391 
10392                 mutex_lock(&perf_sched_mutex);
10393                 if (!atomic_read(&perf_sched_count)) {
10394                         static_branch_enable(&perf_sched_events);
10395                         /*
10396                          * Guarantee that all CPUs observe they key change and
10397                          * call the perf scheduling hooks before proceeding to
10398                          * install events that need them.
10399                          */
10400                         synchronize_rcu();
10401                 }
10402                 /*
10403                  * Now that we have waited for the sync_sched(), allow further
10404                  * increments to by-pass the mutex.
10405                  */
10406                 atomic_inc(&perf_sched_count);
10407                 mutex_unlock(&perf_sched_mutex);
10408         }
10409 enabled:
10410 
10411         account_event_cpu(event, event->cpu);
10412 
10413         account_pmu_sb_event(event);
10414 }
10415 
10416 /*
10417  * Allocate and initialize an event structure
10418  */
10419 static struct perf_event *
10420 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10421                  struct task_struct *task,
10422                  struct perf_event *group_leader,
10423                  struct perf_event *parent_event,
10424                  perf_overflow_handler_t overflow_handler,
10425                  void *context, int cgroup_fd)
10426 {
10427         struct pmu *pmu;
10428         struct perf_event *event;
10429         struct hw_perf_event *hwc;
10430         long err = -EINVAL;
10431 
10432         if ((unsigned)cpu >= nr_cpu_ids) {
10433                 if (!task || cpu != -1)
10434                         return ERR_PTR(-EINVAL);
10435         }
10436 
10437         event = kzalloc(sizeof(*event), GFP_KERNEL);
10438         if (!event)
10439                 return ERR_PTR(-ENOMEM);
10440 
10441         /*
10442          * Single events are their own group leaders, with an
10443          * empty sibling list:
10444          */
10445         if (!group_leader)
10446                 group_leader = event;
10447 
10448         mutex_init(&event->child_mutex);
10449         INIT_LIST_HEAD(&event->child_list);
10450 
10451         INIT_LIST_HEAD(&event->event_entry);
10452         INIT_LIST_HEAD(&event->sibling_list);
10453         INIT_LIST_HEAD(&event->active_list);
10454         init_event_group(event);
10455         INIT_LIST_HEAD(&event->rb_entry);
10456         INIT_LIST_HEAD(&event->active_entry);
10457         INIT_LIST_HEAD(&event->addr_filters.list);
10458         INIT_HLIST_NODE(&event->hlist_entry);
10459 
10460 
10461         init_waitqueue_head(&event->waitq);
10462         event->pending_disable = -1;
10463         init_irq_work(&event->pending, perf_pending_event);
10464 
10465         mutex_init(&event->mmap_mutex);
10466         raw_spin_lock_init(&event->addr_filters.lock);
10467 
10468         atomic_long_set(&event->refcount, 1);
10469         event->cpu              = cpu;
10470         event->attr             = *attr;
10471         event->group_leader     = group_leader;
10472         event->pmu              = NULL;
10473         event->oncpu            = -1;
10474 
10475         event->parent           = parent_event;
10476 
10477         event->ns               = get_pid_ns(task_active_pid_ns(current));
10478         event->id               = atomic64_inc_return(&perf_event_id);
10479 
10480         event->state            = PERF_EVENT_STATE_INACTIVE;
10481 
10482         if (task) {
10483                 event->attach_state = PERF_ATTACH_TASK;
10484                 /*
10485                  * XXX pmu::event_init needs to know what task to account to
10486                  * and we cannot use the ctx information because we need the
10487                  * pmu before we get a ctx.
10488                  */
10489                 event->hw.target = get_task_struct(task);
10490         }
10491 
10492         event->clock = &local_clock;
10493         if (parent_event)
10494                 event->clock = parent_event->clock;
10495 
10496         if (!overflow_handler && parent_event) {
10497                 overflow_handler = parent_event->overflow_handler;
10498                 context = parent_event->overflow_handler_context;
10499 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10500                 if (overflow_handler == bpf_overflow_handler) {
10501                         struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10502 
10503                         if (IS_ERR(prog)) {
10504                                 err = PTR_ERR(prog);
10505                                 goto err_ns;
10506                         }
10507                         event->prog = prog;
10508                         event->orig_overflow_handler =
10509                                 parent_event->orig_overflow_handler;
10510                 }
10511 #endif
10512         }
10513 
10514         if (overflow_handler) {
10515                 event->overflow_handler = overflow_handler;
10516                 event->overflow_handler_context = context;
10517         } else if (is_write_backward(event)){
10518                 event->overflow_handler = perf_event_output_backward;
10519                 event->overflow_handler_context = NULL;
10520         } else {
10521                 event->overflow_handler = perf_event_output_forward;
10522                 event->overflow_handler_context = NULL;
10523         }
10524 
10525         perf_event__state_init(event);
10526 
10527         pmu = NULL;
10528 
10529         hwc = &event->hw;
10530         hwc->sample_period = attr->sample_period;
10531         if (attr->freq && attr->sample_freq)
10532                 hwc->sample_period = 1;
10533         hwc->last_period = hwc->sample_period;
10534 
10535         local64_set(&hwc->period_left, hwc->sample_period);
10536 
10537         /*
10538          * We currently do not support PERF_SAMPLE_READ on inherited events.
10539          * See perf_output_read().
10540          */
10541         if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10542                 goto err_ns;
10543 
10544         if (!has_branch_stack(event))
10545                 event->attr.branch_sample_type = 0;
10546 
10547         if (cgroup_fd != -1) {
10548                 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10549                 if (err)
10550                         goto err_ns;
10551         }
10552 
10553         pmu = perf_init_event(event);
10554         if (IS_ERR(pmu)) {
10555                 err = PTR_ERR(pmu);
10556                 goto err_ns;
10557         }
10558 
10559         /*
10560          * Disallow uncore-cgroup events, they don't make sense as the cgroup will
10561          * be different on other CPUs in the uncore mask.
10562          */
10563         if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
10564                 err = -EINVAL;
10565                 goto err_pmu;
10566         }
10567 
10568         if (event->attr.aux_output &&
10569             !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
10570                 err = -EOPNOTSUPP;
10571                 goto err_pmu;
10572         }
10573 
10574         err = exclusive_event_init(event);
10575         if (err)
10576                 goto err_pmu;
10577 
10578         if (has_addr_filter(event)) {
10579                 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10580                                                     sizeof(struct perf_addr_filter_range),
10581                                                     GFP_KERNEL);
10582                 if (!event->addr_filter_ranges) {
10583                         err = -ENOMEM;
10584                         goto err_per_task;
10585                 }
10586 
10587                 /*
10588                  * Clone the parent's vma offsets: they are valid until exec()
10589                  * even if the mm is not shared with the parent.
10590                  */
10591                 if (event->parent) {
10592                         struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10593 
10594                         raw_spin_lock_irq(&ifh->lock);
10595                         memcpy(event->addr_filter_ranges,
10596                                event->parent->addr_filter_ranges,
10597                                pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10598                         raw_spin_unlock_irq(&ifh->lock);
10599                 }
10600 
10601                 /* force hw sync on the address filters */
10602                 event->addr_filters_gen = 1;
10603         }
10604 
10605         if (!event->parent) {
10606                 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10607                         err = get_callchain_buffers(attr->sample_max_stack);
10608                         if (err)
10609                                 goto err_addr_filters;
10610                 }
10611         }
10612 
10613         /* symmetric to unaccount_event() in _free_event() */
10614         account_event(event);
10615 
10616         return event;
10617 
10618 err_addr_filters:
10619         kfree(event->addr_filter_ranges);
10620 
10621 err_per_task:
10622         exclusive_event_destroy(event);
10623 
10624 err_pmu:
10625         if (event->destroy)
10626                 event->destroy(event);
10627         module_put(pmu->module);
10628 err_ns:
10629         if (is_cgroup_event(event))
10630                 perf_detach_cgroup(event);
10631         if (event->ns)
10632                 put_pid_ns(event->ns);
10633         if (event->hw.target)
10634                 put_task_struct(event->hw.target);
10635         kfree(event);
10636 
10637         return ERR_PTR(err);
10638 }
10639 
10640 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10641                           struct perf_event_attr *attr)
10642 {
10643         u32 size;
10644         int ret;
10645 
10646         /* Zero the full structure, so that a short copy will be nice. */
10647         memset(attr, 0, sizeof(*attr));
10648 
10649         ret = get_user(size, &uattr->size);
10650         if (ret)
10651                 return ret;
10652 
10653         /* ABI compatibility quirk: */
10654         if (!size)
10655                 size = PERF_ATTR_SIZE_VER0;
10656         if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
10657                 goto err_size;
10658 
10659         ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
10660         if (ret) {
10661                 if (ret == -E2BIG)
10662                         goto err_size;
10663                 return ret;
10664         }
10665 
10666         attr->size = size;
10667 
10668         if (attr->__reserved_1 || attr->__reserved_2)
10669                 return -EINVAL;
10670 
10671         if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10672                 return -EINVAL;
10673 
10674         if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10675                 return -EINVAL;
10676 
10677         if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10678                 u64 mask = attr->branch_sample_type;
10679 
10680                 /* only using defined bits */
10681                 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10682                         return -EINVAL;
10683 
10684                 /* at least one branch bit must be set */
10685                 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10686                         return -EINVAL;
10687 
10688                 /* propagate priv level, when not set for branch */
10689                 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10690 
10691                         /* exclude_kernel checked on syscall entry */
10692                         if (!attr->exclude_kernel)
10693                                 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10694 
10695                         if (!attr->exclude_user)
10696                                 mask |= PERF_SAMPLE_BRANCH_USER;
10697 
10698                         if (!attr->exclude_hv)
10699                                 mask |= PERF_SAMPLE_BRANCH_HV;
10700                         /*
10701                          * adjust user setting (for HW filter setup)
10702                          */
10703                         attr->branch_sample_type = mask;
10704                 }
10705                 /* privileged levels capture (kernel, hv): check permissions */
10706                 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10707                     && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10708                         return -EACCES;
10709         }
10710 
10711         if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10712                 ret = perf_reg_validate(attr->sample_regs_user);
10713                 if (ret)
10714                         return ret;
10715         }
10716 
10717         if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10718                 if (!arch_perf_have_user_stack_dump())
10719                         return -ENOSYS;
10720 
10721                 /*
10722                  * We have __u32 type for the size, but so far
10723                  * we can only use __u16 as maximum due to the
10724                  * __u16 sample size limit.
10725                  */
10726                 if (attr->sample_stack_user >= USHRT_MAX)
10727                         return -EINVAL;
10728                 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10729                         return -EINVAL;
10730         }
10731 
10732         if (!attr->sample_max_stack)
10733                 attr->sample_max_stack = sysctl_perf_event_max_stack;
10734 
10735         if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10736                 ret = perf_reg_validate(attr->sample_regs_intr);
10737 out:
10738         return ret;
10739 
10740 err_size:
10741         put_user(sizeof(*attr), &uattr->size);
10742         ret = -E2BIG;
10743         goto out;
10744 }
10745 
10746 static int
10747 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10748 {
10749         struct ring_buffer *rb = NULL;
10750         int ret = -EINVAL;
10751 
10752         if (!output_event)
10753                 goto set;
10754 
10755         /* don't allow circular references */
10756         if (event == output_event)
10757                 goto out;
10758 
10759         /*
10760          * Don't allow cross-cpu buffers
10761          */
10762         if (output_event->cpu != event->cpu)
10763                 goto out;
10764 
10765         /*
10766          * If its not a per-cpu rb, it must be the same task.
10767          */
10768         if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10769                 goto out;
10770 
10771         /*
10772          * Mixing clocks in the same buffer is trouble you don't need.
10773          */
10774         if (output_event->clock != event->clock)
10775                 goto out;
10776 
10777         /*
10778          * Either writing ring buffer from beginning or from end.
10779          * Mixing is not allowed.
10780          */
10781         if (is_write_backward(output_event) != is_write_backward(event))
10782                 goto out;
10783 
10784         /*
10785          * If both events generate aux data, they must be on the same PMU
10786          */
10787         if (has_aux(event) && has_aux(output_event) &&
10788             event->pmu != output_event->pmu)
10789                 goto out;
10790 
10791 set:
10792         mutex_lock(&event->mmap_mutex);
10793         /* Can't redirect output if we've got an active mmap() */
10794         if (atomic_read(&event->mmap_count))
10795                 goto unlock;
10796 
10797         if (output_event) {
10798                 /* get the rb we want to redirect to */
10799                 rb = ring_buffer_get(output_event);
10800                 if (!rb)
10801                         goto unlock;
10802         }
10803 
10804         ring_buffer_attach(event, rb);
10805 
10806         ret = 0;
10807 unlock:
10808         mutex_unlock(&event->mmap_mutex);
10809 
10810 out:
10811         return ret;
10812 }
10813 
10814 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10815 {
10816         if (b < a)
10817                 swap(a, b);
10818 
10819         mutex_lock(a);
10820         mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10821 }
10822 
10823 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10824 {
10825         bool nmi_safe = false;
10826 
10827         switch (clk_id) {
10828         case CLOCK_MONOTONIC:
10829                 event->clock = &ktime_get_mono_fast_ns;
10830                 nmi_safe = true;
10831                 break;
10832 
10833         case CLOCK_MONOTONIC_RAW:
10834                 event->clock = &ktime_get_raw_fast_ns;
10835                 nmi_safe = true;
10836                 break;
10837 
10838         case CLOCK_REALTIME:
10839                 event->clock = &ktime_get_real_ns;
10840                 break;
10841 
10842         case CLOCK_BOOTTIME:
10843                 event->clock = &ktime_get_boottime_ns;
10844                 break;
10845 
10846         case CLOCK_TAI:
10847                 event->clock = &ktime_get_clocktai_ns;
10848                 break;
10849 
10850         default:
10851                 return -EINVAL;
10852         }
10853 
10854         if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10855                 return -EINVAL;
10856 
10857         return 0;
10858 }
10859 
10860 /*
10861  * Variation on perf_event_ctx_lock_nested(), except we take two context
10862  * mutexes.
10863  */
10864 static struct perf_event_context *
10865 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10866                              struct perf_event_context *ctx)
10867 {
10868         struct perf_event_context *gctx;
10869 
10870 again:
10871         rcu_read_lock();
10872         gctx = READ_ONCE(group_leader->ctx);
10873         if (!refcount_inc_not_zero(&gctx->refcount)) {
10874                 rcu_read_unlock();
10875                 goto again;
10876         }
10877         rcu_read_unlock();
10878 
10879         mutex_lock_double(&gctx->mutex, &ctx->mutex);
10880 
10881         if (group_leader->ctx != gctx) {
10882                 mutex_unlock(&ctx->mutex);
10883                 mutex_unlock(&gctx->mutex);
10884                 put_ctx(gctx);
10885                 goto again;
10886         }
10887 
10888         return gctx;
10889 }
10890 
10891 /**
10892  * sys_perf_event_open - open a performance event, associate it to a task/cpu
10893  *
10894  * @attr_uptr:  event_id type attributes for monitoring/sampling
10895  * @pid:                target pid
10896  * @cpu:                target cpu
10897  * @group_fd:           group leader event fd
10898  */
10899 SYSCALL_DEFINE5(perf_event_open,
10900                 struct perf_event_attr __user *, attr_uptr,
10901                 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10902 {
10903         struct perf_event *group_leader = NULL, *output_event = NULL;
10904         struct perf_event *event, *sibling;
10905         struct perf_event_attr attr;
10906         struct perf_event_context *ctx, *uninitialized_var(gctx);
10907         struct file *event_file = NULL;
10908         struct fd group = {NULL, 0};
10909         struct task_struct *task = NULL;
10910         struct pmu *pmu;
10911         int event_fd;
10912         int move_group = 0;
10913         int err;
10914         int f_flags = O_RDWR;
10915         int cgroup_fd = -1;
10916 
10917         /* for future expandability... */
10918         if (flags & ~PERF_FLAG_ALL)
10919                 return -EINVAL;
10920 
10921         err = perf_copy_attr(attr_uptr, &attr);
10922         if (err)
10923                 return err;
10924 
10925         if (!attr.exclude_kernel) {
10926                 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10927                         return -EACCES;
10928         }
10929 
10930         if (attr.namespaces) {
10931                 if (!capable(CAP_SYS_ADMIN))
10932                         return -EACCES;
10933         }
10934 
10935         if (attr.freq) {
10936                 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10937                         return -EINVAL;
10938         } else {
10939                 if (attr.sample_period & (1ULL << 63))
10940                         return -EINVAL;
10941         }
10942 
10943         /* Only privileged users can get physical addresses */
10944         if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10945             perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10946                 return -EACCES;
10947 
10948         err = security_locked_down(LOCKDOWN_PERF);
10949         if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
10950                 /* REGS_INTR can leak data, lockdown must prevent this */
10951                 return err;
10952 
10953         err = 0;
10954 
10955         /*
10956          * In cgroup mode, the pid argument is used to pass the fd
10957          * opened to the cgroup directory in cgroupfs. The cpu argument
10958          * designates the cpu on which to monitor threads from that
10959          * cgroup.
10960          */
10961         if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10962                 return -EINVAL;
10963 
10964         if (flags & PERF_FLAG_FD_CLOEXEC)
10965                 f_flags |= O_CLOEXEC;
10966 
10967         event_fd = get_unused_fd_flags(f_flags);
10968         if (event_fd < 0)
10969                 return event_fd;
10970 
10971         if (group_fd != -1) {
10972                 err = perf_fget_light(group_fd, &group);
10973                 if (err)
10974                         goto err_fd;
10975                 group_leader = group.file->private_data;
10976                 if (flags & PERF_FLAG_FD_OUTPUT)
10977                         output_event = group_leader;
10978                 if (flags & PERF_FLAG_FD_NO_GROUP)
10979                         group_leader = NULL;
10980         }
10981 
10982         if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10983                 task = find_lively_task_by_vpid(pid);
10984                 if (IS_ERR(task)) {
10985                         err = PTR_ERR(task);
10986                         goto err_group_fd;
10987                 }
10988         }
10989 
10990         if (task && group_leader &&
10991             group_leader->attr.inherit != attr.inherit) {
10992                 err = -EINVAL;
10993                 goto err_task;
10994         }
10995 
10996         if (task) {
10997                 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10998                 if (err)
10999                         goto err_task;
11000 
11001                 /*
11002                  * Reuse ptrace permission checks for now.
11003                  *
11004                  * We must hold cred_guard_mutex across this and any potential
11005                  * perf_install_in_context() call for this new event to
11006                  * serialize against exec() altering our credentials (and the
11007                  * perf_event_exit_task() that could imply).
11008                  */
11009                 err = -EACCES;
11010                 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
11011                         goto err_cred;
11012         }
11013 
11014         if (flags & PERF_FLAG_PID_CGROUP)
11015                 cgroup_fd = pid;
11016 
11017         event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
11018                                  NULL, NULL, cgroup_fd);
11019         if (IS_ERR(event)) {
11020                 err = PTR_ERR(event);
11021                 goto err_cred;
11022         }
11023 
11024         if (is_sampling_event(event)) {
11025                 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11026                         err = -EOPNOTSUPP;
11027                         goto err_alloc;
11028                 }
11029         }
11030 
11031         /*
11032          * Special case software events and allow them to be part of
11033          * any hardware group.
11034          */
11035         pmu = event->pmu;
11036 
11037         if (attr.use_clockid) {
11038                 err = perf_event_set_clock(event, attr.clockid);
11039                 if (err)
11040                         goto err_alloc;
11041         }
11042 
11043         if (pmu->task_ctx_nr == perf_sw_context)
11044                 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11045 
11046         if (group_leader) {
11047                 if (is_software_event(event) &&
11048                     !in_software_context(group_leader)) {
11049                         /*
11050                          * If the event is a sw event, but the group_leader
11051                          * is on hw context.
11052                          *
11053                          * Allow the addition of software events to hw
11054                          * groups, this is safe because software events
11055                          * never fail to schedule.
11056                          */
11057                         pmu = group_leader->ctx->pmu;
11058                 } else if (!is_software_event(event) &&
11059                            is_software_event(group_leader) &&
11060                            (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11061                         /*
11062                          * In case the group is a pure software group, and we
11063                          * try to add a hardware event, move the whole group to
11064                          * the hardware context.
11065                          */
11066                         move_group = 1;
11067                 }
11068         }
11069 
11070         /*
11071          * Get the target context (task or percpu):
11072          */
11073         ctx = find_get_context(pmu, task, event);
11074         if (IS_ERR(ctx)) {
11075                 err = PTR_ERR(ctx);
11076                 goto err_alloc;
11077         }
11078 
11079         /*
11080          * Look up the group leader (we will attach this event to it):
11081          */
11082         if (group_leader) {
11083                 err = -EINVAL;
11084 
11085                 /*
11086                  * Do not allow a recursive hierarchy (this new sibling
11087                  * becoming part of another group-sibling):
11088                  */
11089                 if (group_leader->group_leader != group_leader)
11090                         goto err_context;
11091 
11092                 /* All events in a group should have the same clock */
11093                 if (group_leader->clock != event->clock)
11094                         goto err_context;
11095 
11096                 /*
11097                  * Make sure we're both events for the same CPU;
11098                  * grouping events for different CPUs is broken; since
11099                  * you can never concurrently schedule them anyhow.
11100                  */
11101                 if (group_leader->cpu != event->cpu)
11102                         goto err_context;
11103 
11104                 /*
11105                  * Make sure we're both on the same task, or both
11106                  * per-CPU events.
11107                  */
11108                 if (group_leader->ctx->task != ctx->task)
11109                         goto err_context;
11110 
11111                 /*
11112                  * Do not allow to attach to a group in a different task
11113                  * or CPU context. If we're moving SW events, we'll fix
11114                  * this up later, so allow that.
11115                  */
11116                 if (!move_group && group_leader->ctx != ctx)
11117                         goto err_context;
11118 
11119                 /*
11120                  * Only a group leader can be exclusive or pinned
11121                  */
11122                 if (attr.exclusive || attr.pinned)
11123                         goto err_context;
11124         }
11125 
11126         if (output_event) {
11127                 err = perf_event_set_output(event, output_event);
11128                 if (err)
11129                         goto err_context;
11130         }
11131 
11132         event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11133                                         f_flags);
11134         if (IS_ERR(event_file)) {
11135                 err = PTR_ERR(event_file);
11136                 event_file = NULL;
11137                 goto err_context;
11138         }
11139 
11140         if (move_group) {
11141                 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11142 
11143                 if (gctx->task == TASK_TOMBSTONE) {
11144                         err = -ESRCH;
11145                         goto err_locked;
11146                 }
11147 
11148                 /*
11149                  * Check if we raced against another sys_perf_event_open() call
11150                  * moving the software group underneath us.
11151                  */
11152                 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11153                         /*
11154                          * If someone moved the group out from under us, check
11155                          * if this new event wound up on the same ctx, if so
11156                          * its the regular !move_group case, otherwise fail.
11157                          */
11158                         if (gctx != ctx) {
11159                                 err = -EINVAL;
11160                                 goto err_locked;
11161                         } else {
11162                                 perf_event_ctx_unlock(group_leader, gctx);
11163                                 move_group = 0;
11164                         }
11165                 }
11166 
11167                 /*
11168                  * Failure to create exclusive events returns -EBUSY.
11169                  */
11170                 err = -EBUSY;
11171                 if (!exclusive_event_installable(group_leader, ctx))
11172                         goto err_locked;
11173 
11174                 for_each_sibling_event(sibling, group_leader) {
11175                         if (!exclusive_event_installable(sibling, ctx))
11176                                 goto err_locked;
11177                 }
11178         } else {
11179                 mutex_lock(&ctx->mutex);
11180         }
11181 
11182         if (ctx->task == TASK_TOMBSTONE) {
11183                 err = -ESRCH;
11184                 goto err_locked;
11185         }
11186 
11187         if (!perf_event_validate_size(event)) {
11188                 err = -E2BIG;
11189                 goto err_locked;
11190         }
11191 
11192         if (!task) {
11193                 /*
11194                  * Check if the @cpu we're creating an event for is online.
11195                  *
11196                  * We use the perf_cpu_context::ctx::mutex to serialize against
11197                  * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11198                  */
11199                 struct perf_cpu_context *cpuctx =
11200                         container_of(ctx, struct perf_cpu_context, ctx);
11201 
11202                 if (!cpuctx->online) {
11203                         err = -ENODEV;
11204                         goto err_locked;
11205                 }
11206         }
11207 
11208         if (event->attr.aux_output && !perf_get_aux_event(event, group_leader)) {
11209                 err = -EINVAL;
11210                 goto err_locked;
11211         }
11212 
11213         /*
11214          * Must be under the same ctx::mutex as perf_install_in_context(),
11215          * because we need to serialize with concurrent event creation.
11216          */
11217         if (!exclusive_event_installable(event, ctx)) {
11218                 err = -EBUSY;
11219                 goto err_locked;
11220         }
11221 
11222         WARN_ON_ONCE(ctx->parent_ctx);
11223 
11224         /*
11225          * This is the point on no return; we cannot fail hereafter. This is
11226          * where we start modifying current state.
11227          */
11228 
11229         if (move_group) {
11230                 /*
11231                  * See perf_event_ctx_lock() for comments on the details
11232                  * of swizzling perf_event::ctx.
11233                  */
11234                 perf_remove_from_context(group_leader, 0);
11235                 put_ctx(gctx);
11236 
11237                 for_each_sibling_event(sibling, group_leader) {
11238                         perf_remove_from_context(sibling, 0);
11239                         put_ctx(gctx);
11240                 }
11241 
11242                 /*
11243                  * Wait for everybody to stop referencing the events through
11244                  * the old lists, before installing it on new lists.
11245                  */
11246                 synchronize_rcu();
11247 
11248                 /*
11249                  * Install the group siblings before the group leader.
11250                  *
11251                  * Because a group leader will try and install the entire group
11252                  * (through the sibling list, which is still in-tact), we can
11253                  * end up with siblings installed in the wrong context.
11254                  *
11255                  * By installing siblings first we NO-OP because they're not
11256                  * reachable through the group lists.
11257                  */
11258                 for_each_sibling_event(sibling, group_leader) {
11259                         perf_event__state_init(sibling);
11260                         perf_install_in_context(ctx, sibling, sibling->cpu);
11261                         get_ctx(ctx);
11262                 }
11263 
11264                 /*
11265                  * Removing from the context ends up with disabled
11266                  * event. What we want here is event in the initial
11267                  * startup state, ready to be add into new context.
11268                  */
11269                 perf_event__state_init(group_leader);
11270                 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11271                 get_ctx(ctx);
11272         }
11273 
11274         /*
11275          * Precalculate sample_data sizes; do while holding ctx::mutex such
11276          * that we're serialized against further additions and before
11277          * perf_install_in_context() which is the point the event is active and
11278          * can use these values.
11279          */
11280         perf_event__header_size(event);
11281         perf_event__id_header_size(event);
11282 
11283         event->owner = current;
11284 
11285         perf_install_in_context(ctx, event, event->cpu);
11286         perf_unpin_context(ctx);
11287 
11288         if (move_group)
11289                 perf_event_ctx_unlock(group_leader, gctx);
11290         mutex_unlock(&ctx->mutex);
11291 
11292         if (task) {
11293                 mutex_unlock(&task->signal->cred_guard_mutex);
11294                 put_task_struct(task);
11295         }
11296 
11297         mutex_lock(&current->perf_event_mutex);
11298         list_add_tail(&event->owner_entry, &current->perf_event_list);
11299         mutex_unlock(&current->perf_event_mutex);
11300 
11301         /*
11302          * Drop the reference on the group_event after placing the
11303          * new event on the sibling_list. This ensures destruction
11304          * of the group leader will find the pointer to itself in
11305          * perf_group_detach().
11306          */
11307         fdput(group);
11308         fd_install(event_fd, event_file);
11309         return event_fd;
11310 
11311 err_locked:
11312         if (move_group)
11313                 perf_event_ctx_unlock(group_leader, gctx);
11314         mutex_unlock(&ctx->mutex);
11315 /* err_file: */
11316         fput(event_file);
11317 err_context:
11318         perf_unpin_context(ctx);
11319         put_ctx(ctx);
11320 err_alloc:
11321         /*
11322          * If event_file is set, the fput() above will have called ->release()
11323          * and that will take care of freeing the event.
11324          */
11325         if (!event_file)
11326                 free_event(event);
11327 err_cred:
11328         if (task)
11329                 mutex_unlock(&task->signal->cred_guard_mutex);
11330 err_task:
11331         if (task)
11332                 put_task_struct(task);
11333 err_group_fd:
11334         fdput(group);
11335 err_fd:
11336         put_unused_fd(event_fd);
11337         return err;
11338 }
11339 
11340 /**
11341  * perf_event_create_kernel_counter
11342  *
11343  * @attr: attributes of the counter to create
11344  * @cpu: cpu in which the counter is bound
11345  * @task: task to profile (NULL for percpu)
11346  */
11347 struct perf_event *
11348 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11349                                  struct task_struct *task,
11350                                  perf_overflow_handler_t overflow_handler,
11351                                  void *context)
11352 {
11353         struct perf_event_context *ctx;
11354         struct perf_event *event;
11355         int err;
11356 
11357         /*
11358          * Grouping is not supported for kernel events, neither is 'AUX',
11359          * make sure the caller's intentions are adjusted.
11360          */
11361         if (attr->aux_output)
11362                 return ERR_PTR(-EINVAL);
11363 
11364         event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11365                                  overflow_handler, context, -1);
11366         if (IS_ERR(event)) {
11367                 err = PTR_ERR(event);
11368                 goto err;
11369         }
11370 
11371         /* Mark owner so we could distinguish it from user events. */
11372         event->owner = TASK_TOMBSTONE;
11373 
11374         /*
11375          * Get the target context (task or percpu):
11376          */
11377         ctx = find_get_context(event->pmu, task, event);
11378         if (IS_ERR(ctx)) {
11379                 err = PTR_ERR(ctx);
11380                 goto err_free;
11381         }
11382 
11383         WARN_ON_ONCE(ctx->parent_ctx);
11384         mutex_lock(&ctx->mutex);
11385         if (ctx->task == TASK_TOMBSTONE) {
11386                 err = -ESRCH;
11387                 goto err_unlock;
11388         }
11389 
11390         if (!task) {
11391                 /*
11392                  * Check if the @cpu we're creating an event for is online.
11393                  *
11394                  * We use the perf_cpu_context::ctx::mutex to serialize against
11395                  * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11396                  */
11397                 struct perf_cpu_context *cpuctx =
11398                         container_of(ctx, struct perf_cpu_context, ctx);
11399                 if (!cpuctx->online) {
11400                         err = -ENODEV;
11401                         goto err_unlock;
11402                 }
11403         }
11404 
11405         if (!exclusive_event_installable(event, ctx)) {
11406                 err = -EBUSY;
11407                 goto err_unlock;
11408         }
11409 
11410         perf_install_in_context(ctx, event, event->cpu);
11411         perf_unpin_context(ctx);
11412         mutex_unlock(&ctx->mutex);
11413 
11414         return event;
11415 
11416 err_unlock:
11417         mutex_unlock(&ctx->mutex);
11418         perf_unpin_context(ctx);
11419         put_ctx(ctx);
11420 err_free:
11421         free_event(event);
11422 err:
11423         return ERR_PTR(err);
11424 }
11425 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11426 
11427 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11428 {
11429         struct perf_event_context *src_ctx;
11430         struct perf_event_context *dst_ctx;
11431         struct perf_event *event, *tmp;
11432         LIST_HEAD(events);
11433 
11434         src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11435         dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11436 
11437         /*
11438          * See perf_event_ctx_lock() for comments on the details
11439          * of swizzling perf_event::ctx.
11440          */
11441         mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11442         list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11443                                  event_entry) {
11444                 perf_remove_from_context(event, 0);
11445                 unaccount_event_cpu(event, src_cpu);
11446                 put_ctx(src_ctx);
11447                 list_add(&event->migrate_entry, &events);
11448         }
11449 
11450         /*
11451          * Wait for the events to quiesce before re-instating them.
11452          */
11453         synchronize_rcu();
11454 
11455         /*
11456          * Re-instate events in 2 passes.
11457          *
11458          * Skip over group leaders and only install siblings on this first
11459          * pass, siblings will not get enabled without a leader, however a
11460          * leader will enable its siblings, even if those are still on the old
11461          * context.
11462          */
11463         list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11464                 if (event->group_leader == event)
11465                         continue;
11466 
11467                 list_del(&event->migrate_entry);
11468                 if (event->state >= PERF_EVENT_STATE_OFF)
11469                         event->state = PERF_EVENT_STATE_INACTIVE;
11470                 account_event_cpu(event, dst_cpu);
11471                 perf_install_in_context(dst_ctx, event, dst_cpu);
11472                 get_ctx(dst_ctx);
11473         }
11474 
11475         /*
11476          * Once all the siblings are setup properly, install the group leaders
11477          * to make it go.
11478          */
11479         list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11480                 list_del(&event->migrate_entry);
11481                 if (event->state >= PERF_EVENT_STATE_OFF)
11482                         event->state = PERF_EVENT_STATE_INACTIVE;
11483                 account_event_cpu(event, dst_cpu);
11484                 perf_install_in_context(dst_ctx, event, dst_cpu);
11485                 get_ctx(dst_ctx);
11486         }
11487         mutex_unlock(&dst_ctx->mutex);
11488         mutex_unlock(&src_ctx->mutex);
11489 }
11490 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11491 
11492 static void sync_child_event(struct perf_event *child_event,
11493                                struct task_struct *child)
11494 {
11495         struct perf_event *parent_event = child_event->parent;
11496         u64 child_val;
11497 
11498         if (child_event->attr.inherit_stat)
11499                 perf_event_read_event(child_event, child);
11500 
11501         child_val = perf_event_count(child_event);
11502 
11503         /*
11504          * Add back the child's count to the parent's count:
11505          */
11506         atomic64_add(child_val, &parent_event->child_count);
11507         atomic64_add(child_event->total_time_enabled,
11508                      &parent_event->child_total_time_enabled);
11509         atomic64_add(child_event->total_time_running,
11510                      &parent_event->child_total_time_running);
11511 }
11512 
11513 static void
11514 perf_event_exit_event(struct perf_event *child_event,
11515                       struct perf_event_context *child_ctx,
11516                       struct task_struct *child)
11517 {
11518         struct perf_event *parent_event = child_event->parent;
11519 
11520         /*
11521          * Do not destroy the 'original' grouping; because of the context
11522          * switch optimization the original events could've ended up in a
11523          * random child task.
11524          *
11525          * If we were to destroy the original group, all group related
11526          * operations would cease to function properly after this random
11527          * child dies.
11528          *
11529          * Do destroy all inherited groups, we don't care about those
11530          * and being thorough is better.
11531          */
11532         raw_spin_lock_irq(&child_ctx->lock);
11533         WARN_ON_ONCE(child_ctx->is_active);
11534 
11535         if (parent_event)
11536                 perf_group_detach(child_event);
11537         list_del_event(child_event, child_ctx);
11538         perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11539         raw_spin_unlock_irq(&child_ctx->lock);
11540 
11541         /*
11542          * Parent events are governed by their filedesc, retain them.
11543          */
11544         if (!parent_event) {
11545                 perf_event_wakeup(child_event);
11546                 return;
11547         }
11548         /*
11549          * Child events can be cleaned up.
11550          */
11551 
11552         sync_child_event(child_event, child);
11553 
11554         /*
11555          * Remove this event from the parent's list
11556          */
11557         WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11558         mutex_lock(&parent_event->child_mutex);
11559         list_del_init(&child_event->child_list);
11560         mutex_unlock(&parent_event->child_mutex);
11561 
11562         /*
11563          * Kick perf_poll() for is_event_hup().
11564          */
11565         perf_event_wakeup(parent_event);
11566         free_event(child_event);
11567         put_event(parent_event);
11568 }
11569 
11570 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11571 {
11572         struct perf_event_context *child_ctx, *clone_ctx = NULL;
11573         struct perf_event *child_event, *next;
11574 
11575         WARN_ON_ONCE(child != current);
11576 
11577         child_ctx = perf_pin_task_context(child, ctxn);
11578         if (!child_ctx)
11579                 return;
11580 
11581         /*
11582          * In order to reduce the amount of tricky in ctx tear-down, we hold
11583          * ctx::mutex over the entire thing. This serializes against almost
11584          * everything that wants to access the ctx.
11585          *
11586          * The exception is sys_perf_event_open() /
11587          * perf_event_create_kernel_count() which does find_get_context()
11588          * without ctx::mutex (it cannot because of the move_group double mutex
11589          * lock thing). See the comments in perf_install_in_context().
11590          */
11591         mutex_lock(&child_ctx->mutex);
11592 
11593         /*
11594          * In a single ctx::lock section, de-schedule the events and detach the
11595          * context from the task such that we cannot ever get it scheduled back
11596          * in.
11597          */
11598         raw_spin_lock_irq(&child_ctx->lock);
11599         task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11600 
11601         /*
11602          * Now that the context is inactive, destroy the task <-> ctx relation
11603          * and mark the context dead.
11604          */
11605         RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11606         put_ctx(child_ctx); /* cannot be last */
11607         WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11608         put_task_struct(current); /* cannot be last */
11609 
11610         clone_ctx = unclone_ctx(child_ctx);
11611         raw_spin_unlock_irq(&child_ctx->lock);
11612 
11613         if (clone_ctx)
11614                 put_ctx(clone_ctx);
11615 
11616         /*
11617          * Report the task dead after unscheduling the events so that we
11618          * won't get any samples after PERF_RECORD_EXIT. We can however still
11619          * get a few PERF_RECORD_READ events.
11620          */
11621         perf_event_task(child, child_ctx, 0);
11622 
11623         list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11624                 perf_event_exit_event(child_event, child_ctx, child);
11625 
11626         mutex_unlock(&child_ctx->mutex);
11627 
11628         put_ctx(child_ctx);
11629 }
11630 
11631 /*
11632  * When a child task exits, feed back event values to parent events.
11633  *
11634  * Can be called with cred_guard_mutex held when called from
11635  * install_exec_creds().
11636  */
11637 void perf_event_exit_task(struct task_struct *child)
11638 {
11639         struct perf_event *event, *tmp;
11640         int ctxn;
11641 
11642         mutex_lock(&child->perf_event_mutex);
11643         list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11644                                  owner_entry) {
11645                 list_del_init(&event->owner_entry);
11646 
11647                 /*
11648                  * Ensure the list deletion is visible before we clear
11649                  * the owner, closes a race against perf_release() where
11650                  * we need to serialize on the owner->perf_event_mutex.
11651                  */
11652                 smp_store_release(&event->owner, NULL);
11653         }
11654         mutex_unlock(&child->perf_event_mutex);
11655 
11656         for_each_task_context_nr(ctxn)
11657                 perf_event_exit_task_context(child, ctxn);
11658 
11659         /*
11660          * The perf_event_exit_task_context calls perf_event_task
11661          * with child's task_ctx, which generates EXIT events for
11662          * child contexts and sets child->perf_event_ctxp[] to NULL.
11663          * At this point we need to send EXIT events to cpu contexts.
11664          */
11665         perf_event_task(child, NULL, 0);
11666 }
11667 
11668 static void perf_free_event(struct perf_event *event,
11669                             struct perf_event_context *ctx)
11670 {
11671         struct perf_event *parent = event->parent;
11672 
11673         if (WARN_ON_ONCE(!parent))
11674                 return;
11675 
11676         mutex_lock(&parent->child_mutex);
11677         list_del_init(&event->child_list);
11678         mutex_unlock(&parent->child_mutex);
11679 
11680         put_event(parent);
11681 
11682         raw_spin_lock_irq(&ctx->lock);
11683         perf_group_detach(event);
11684         list_del_event(event, ctx);
11685         raw_spin_unlock_irq(&ctx->lock);
11686         free_event(event);
11687 }
11688 
11689 /*
11690  * Free a context as created by inheritance by perf_event_init_task() below,
11691  * used by fork() in case of fail.
11692  *
11693  * Even though the task has never lived, the context and events have been
11694  * exposed through the child_list, so we must take care tearing it all down.
11695  */
11696 void perf_event_free_task(struct task_struct *task)
11697 {
11698         struct perf_event_context *ctx;
11699         struct perf_event *event, *tmp;
11700         int ctxn;
11701 
11702         for_each_task_context_nr(ctxn) {
11703                 ctx = task->perf_event_ctxp[ctxn];
11704                 if (!ctx)
11705                         continue;
11706 
11707                 mutex_lock(&ctx->mutex);
11708                 raw_spin_lock_irq(&ctx->lock);
11709                 /*
11710                  * Destroy the task <-> ctx relation and mark the context dead.
11711                  *
11712                  * This is important because even though the task hasn't been
11713                  * exposed yet the context has been (through child_list).
11714                  */
11715                 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11716                 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11717                 put_task_struct(task); /* cannot be last */
11718                 raw_spin_unlock_irq(&ctx->lock);
11719 
11720                 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11721                         perf_free_event(event, ctx);
11722 
11723                 mutex_unlock(&ctx->mutex);
11724 
11725                 /*
11726                  * perf_event_release_kernel() could've stolen some of our
11727                  * child events and still have them on its free_list. In that
11728                  * case we must wait for these events to have been freed (in
11729                  * particular all their references to this task must've been
11730                  * dropped).
11731                  *
11732                  * Without this copy_process() will unconditionally free this
11733                  * task (irrespective of its reference count) and
11734                  * _free_event()'s put_task_struct(event->hw.target) will be a
11735                  * use-after-free.
11736                  *
11737                  * Wait for all events to drop their context reference.
11738                  */
11739                 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
11740                 put_ctx(ctx); /* must be last */
11741         }
11742 }
11743 
11744 void perf_event_delayed_put(struct task_struct *task)
11745 {
11746         int ctxn;
11747 
11748         for_each_task_context_nr(ctxn)
11749                 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11750 }
11751 
11752 struct file *perf_event_get(unsigned int fd)
11753 {
11754         struct file *file = fget(fd);
11755         if (!file)
11756                 return ERR_PTR(-EBADF);
11757 
11758         if (file->f_op != &perf_fops) {
11759                 fput(file);
11760                 return ERR_PTR(-EBADF);
11761         }
11762 
11763         return file;
11764 }
11765 
11766 const struct perf_event *perf_get_event(struct file *file)
11767 {
11768         if (file->f_op != &perf_fops)
11769                 return ERR_PTR(-EINVAL);
11770 
11771         return file->private_data;
11772 }
11773 
11774 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11775 {
11776         if (!event)
11777                 return ERR_PTR(-EINVAL);
11778 
11779         return &event->attr;
11780 }
11781 
11782 /*
11783  * Inherit an event from parent task to child task.
11784  *
11785  * Returns:
11786  *  - valid pointer on success
11787  *  - NULL for orphaned events
11788  *  - IS_ERR() on error
11789  */
11790 static struct perf_event *
11791 inherit_event(struct perf_event *parent_event,
11792               struct task_struct *parent,
11793               struct perf_event_context *parent_ctx,
11794               struct task_struct *child,
11795               struct perf_event *group_leader,
11796               struct perf_event_context *child_ctx)
11797 {
11798         enum perf_event_state parent_state = parent_event->state;
11799         struct perf_event *child_event;
11800         unsigned long flags;
11801 
11802         /*
11803          * Instead of creating recursive hierarchies of events,
11804          * we link inherited events back to the original parent,
11805          * which has a filp for sure, which we use as the reference
11806          * count:
11807          */
11808         if (parent_event->parent)
11809                 parent_event = parent_event->parent;
11810 
11811         child_event = perf_event_alloc(&parent_event->attr,
11812                                            parent_event->cpu,
11813                                            child,
11814                                            group_leader, parent_event,
11815                                            NULL, NULL, -1);
11816         if (IS_ERR(child_event))
11817                 return child_event;
11818 
11819 
11820         if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11821             !child_ctx->task_ctx_data) {
11822                 struct pmu *pmu = child_event->pmu;
11823 
11824                 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11825                                                    GFP_KERNEL);
11826                 if (!child_ctx->task_ctx_data) {
11827                         free_event(child_event);
11828                         return ERR_PTR(-ENOMEM);
11829                 }
11830         }
11831 
11832         /*
11833          * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11834          * must be under the same lock in order to serialize against
11835          * perf_event_release_kernel(), such that either we must observe
11836          * is_orphaned_event() or they will observe us on the child_list.
11837          */
11838         mutex_lock(&parent_event->child_mutex);
11839         if (is_orphaned_event(parent_event) ||
11840             !atomic_long_inc_not_zero(&parent_event->refcount)) {
11841                 mutex_unlock(&parent_event->child_mutex);
11842                 /* task_ctx_data is freed with child_ctx */
11843                 free_event(child_event);
11844                 return NULL;
11845         }
11846 
11847         get_ctx(child_ctx);
11848 
11849         /*
11850          * Make the child state follow the state of the parent event,
11851          * not its attr.disabled bit.  We hold the parent's mutex,
11852          * so we won't race with perf_event_{en, dis}able_family.
11853          */
11854         if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11855                 child_event->state = PERF_EVENT_STATE_INACTIVE;
11856         else
11857                 child_event->state = PERF_EVENT_STATE_OFF;
11858 
11859         if (parent_event->attr.freq) {
11860                 u64 sample_period = parent_event->hw.sample_period;
11861                 struct hw_perf_event *hwc = &child_event->hw;
11862 
11863                 hwc->sample_period = sample_period;
11864                 hwc->last_period   = sample_period;
11865 
11866                 local64_set(&hwc->period_left, sample_period);
11867         }
11868 
11869         child_event->ctx = child_ctx;
11870         child_event->overflow_handler = parent_event->overflow_handler;
11871         child_event->overflow_handler_context
11872                 = parent_event->overflow_handler_context;
11873 
11874         /*
11875          * Precalculate sample_data sizes
11876          */
11877         perf_event__header_size(child_event);
11878         perf_event__id_header_size(child_event);
11879 
11880         /*
11881          * Link it up in the child's context:
11882          */
11883         raw_spin_lock_irqsave(&child_ctx->lock, flags);
11884         add_event_to_ctx(child_event, child_ctx);
11885         raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11886 
11887         /*
11888          * Link this into the parent event's child list
11889          */
11890         list_add_tail(&child_event->child_list, &parent_event->child_list);
11891         mutex_unlock(&parent_event->child_mutex);
11892 
11893         return child_event;
11894 }
11895 
11896 /*
11897  * Inherits an event group.
11898  *
11899  * This will quietly suppress orphaned events; !inherit_event() is not an error.
11900  * This matches with perf_event_release_kernel() removing all child events.
11901  *
11902  * Returns:
11903  *  - 0 on success
11904  *  - <0 on error
11905  */
11906 static int inherit_group(struct perf_event *parent_event,
11907               struct task_struct *parent,
11908               struct perf_event_context *parent_ctx,
11909               struct task_struct *child,
11910               struct perf_event_context *child_ctx)
11911 {
11912         struct perf_event *leader;
11913         struct perf_event *sub;
11914         struct perf_event *child_ctr;
11915 
11916         leader = inherit_event(parent_event, parent, parent_ctx,
11917                                  child, NULL, child_ctx);
11918         if (IS_ERR(leader))
11919                 return PTR_ERR(leader);
11920         /*
11921          * @leader can be NULL here because of is_orphaned_event(). In this
11922          * case inherit_event() will create individual events, similar to what
11923          * perf_group_detach() would do anyway.
11924          */
11925         for_each_sibling_event(sub, parent_event) {
11926                 child_ctr = inherit_event(sub, parent, parent_ctx,
11927                                             child, leader, child_ctx);
11928                 if (IS_ERR(child_ctr))
11929                         return PTR_ERR(child_ctr);
11930 
11931                 if (sub->aux_event == parent_event && child_ctr &&
11932                     !perf_get_aux_event(child_ctr, leader))
11933                         return -EINVAL;
11934         }
11935         return 0;
11936 }
11937 
11938 /*
11939  * Creates the child task context and tries to inherit the event-group.
11940  *
11941  * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11942  * inherited_all set when we 'fail' to inherit an orphaned event; this is
11943  * consistent with perf_event_release_kernel() removing all child events.
11944  *
11945  * Returns:
11946  *  - 0 on success
11947  *  - <0 on error
11948  */
11949 static int
11950 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11951                    struct perf_event_context *parent_ctx,
11952                    struct task_struct *child, int ctxn,
11953                    int *inherited_all)
11954 {
11955         int ret;
11956         struct perf_event_context *child_ctx;
11957 
11958         if (!event->attr.inherit) {
11959                 *inherited_all = 0;
11960                 return 0;
11961         }
11962 
11963         child_ctx = child->perf_event_ctxp[ctxn];
11964         if (!child_ctx) {
11965                 /*
11966                  * This is executed from the parent task context, so
11967                  * inherit events that have been marked for cloning.
11968                  * First allocate and initialize a context for the
11969                  * child.
11970                  */
11971                 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11972                 if (!child_ctx)
11973                         return -ENOMEM;
11974 
11975                 child->perf_event_ctxp[ctxn] = child_ctx;
11976         }
11977 
11978         ret = inherit_group(event, parent, parent_ctx,
11979                             child, child_ctx);
11980 
11981         if (ret)
11982                 *inherited_all = 0;
11983 
11984         return ret;
11985 }
11986 
11987 /*
11988  * Initialize the perf_event context in task_struct
11989  */
11990 static int perf_event_init_context(struct task_struct *child, int ctxn)
11991 {
11992         struct perf_event_context *child_ctx, *parent_ctx;
11993         struct perf_event_context *cloned_ctx;
11994         struct perf_event *event;
11995         struct task_struct *parent = current;
11996         int inherited_all = 1;
11997         unsigned long flags;
11998         int ret = 0;
11999 
12000         if (likely(!parent->perf_event_ctxp[ctxn]))
12001                 return 0;
12002 
12003         /*
12004          * If the parent's context is a clone, pin it so it won't get
12005          * swapped under us.
12006          */
12007         parent_ctx = perf_pin_task_context(parent, ctxn);
12008         if (!parent_ctx)
12009                 return 0;
12010 
12011         /*
12012          * No need to check if parent_ctx != NULL here; since we saw
12013          * it non-NULL earlier, the only reason for it to become NULL
12014          * is if we exit, and since we're currently in the middle of
12015          * a fork we can't be exiting at the same time.
12016          */
12017 
12018         /*
12019          * Lock the parent list. No need to lock the child - not PID
12020          * hashed yet and not running, so nobody can access it.
12021          */
12022         mutex_lock(&parent_ctx->mutex);
12023 
12024         /*
12025          * We dont have to disable NMIs - we are only looking at
12026          * the list, not manipulating it:
12027          */
12028         perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12029                 ret = inherit_task_group(event, parent, parent_ctx,
12030                                          child, ctxn, &inherited_all);
12031                 if (ret)
12032                         goto out_unlock;
12033         }
12034 
12035         /*
12036          * We can't hold ctx->lock when iterating the ->flexible_group list due
12037          * to allocations, but we need to prevent rotation because
12038          * rotate_ctx() will change the list from interrupt context.
12039          */
12040         raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12041         parent_ctx->rotate_disable = 1;
12042         raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12043 
12044         perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12045                 ret = inherit_task_group(event, parent, parent_ctx,
12046                                          child, ctxn, &inherited_all);
12047                 if (ret)
12048                         goto out_unlock;
12049         }
12050 
12051         raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12052         parent_ctx->rotate_disable = 0;
12053 
12054         child_ctx = child->perf_event_ctxp[ctxn];
12055 
12056         if (child_ctx && inherited_all) {
12057                 /*
12058                  * Mark the child context as a clone of the parent
12059                  * context, or of whatever the parent is a clone of.
12060                  *
12061                  * Note that if the parent is a clone, the holding of
12062                  * parent_ctx->lock avoids it from being uncloned.
12063                  */
12064                 cloned_ctx = parent_ctx->parent_ctx;
12065                 if (cloned_ctx) {
12066                         child_ctx->parent_ctx = cloned_ctx;
12067                         child_ctx->parent_gen = parent_ctx->parent_gen;
12068                 } else {
12069                         child_ctx->parent_ctx = parent_ctx;
12070                         child_ctx->parent_gen = parent_ctx->generation;
12071                 }
12072                 get_ctx(child_ctx->parent_ctx);
12073         }
12074 
12075         raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12076 out_unlock:
12077         mutex_unlock(&parent_ctx->mutex);
12078 
12079         perf_unpin_context(parent_ctx);
12080         put_ctx(parent_ctx);
12081 
12082         return ret;
12083 }
12084 
12085 /*
12086  * Initialize the perf_event context in task_struct
12087  */
12088 int perf_event_init_task(struct task_struct *child)
12089 {
12090         int ctxn, ret;
12091 
12092         memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12093         mutex_init(&child->perf_event_mutex);
12094         INIT_LIST_HEAD(&child->perf_event_list);
12095 
12096         for_each_task_context_nr(ctxn) {
12097                 ret = perf_event_init_context(child, ctxn);
12098                 if (ret) {
12099                         perf_event_free_task(child);
12100                         return ret;
12101                 }
12102         }
12103 
12104         return 0;
12105 }
12106 
12107 static void __init perf_event_init_all_cpus(void)
12108 {
12109         struct swevent_htable *swhash;
12110         int cpu;
12111 
12112         zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12113 
12114         for_each_possible_cpu(cpu) {
12115                 swhash = &per_cpu(swevent_htable, cpu);
12116                 mutex_init(&swhash->hlist_mutex);
12117                 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12118 
12119                 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12120                 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12121 
12122 #ifdef CONFIG_CGROUP_PERF
12123                 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12124 #endif
12125                 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12126         }
12127 }
12128 
12129 static void perf_swevent_init_cpu(unsigned int cpu)
12130 {
12131         struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12132 
12133         mutex_lock(&swhash->hlist_mutex);
12134         if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12135                 struct swevent_hlist *hlist;
12136 
12137                 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12138                 WARN_ON(!hlist);
12139                 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12140         }
12141         mutex_unlock(&swhash->hlist_mutex);
12142 }
12143 
12144 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12145 static void __perf_event_exit_context(void *__info)
12146 {
12147         struct perf_event_context *ctx = __info;
12148         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12149         struct perf_event *event;
12150 
12151         raw_spin_lock(&ctx->lock);
12152         ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12153         list_for_each_entry(event, &ctx->event_list, event_entry)
12154                 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12155         raw_spin_unlock(&ctx->lock);
12156 }
12157 
12158 static void perf_event_exit_cpu_context(int cpu)
12159 {
12160         struct perf_cpu_context *cpuctx;
12161         struct perf_event_context *ctx;
12162         struct pmu *pmu;
12163 
12164         mutex_lock(&pmus_lock);
12165         list_for_each_entry(pmu, &pmus, entry) {
12166                 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12167                 ctx = &cpuctx->ctx;
12168 
12169                 mutex_lock(&ctx->mutex);
12170                 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12171                 cpuctx->online = 0;
12172                 mutex_unlock(&ctx->mutex);
12173         }
12174         cpumask_clear_cpu(cpu, perf_online_mask);
12175         mutex_unlock(&pmus_lock);
12176 }
12177 #else
12178 
12179 static void perf_event_exit_cpu_context(int cpu) { }
12180 
12181 #endif
12182 
12183 int perf_event_init_cpu(unsigned int cpu)
12184 {
12185         struct perf_cpu_context *cpuctx;
12186         struct perf_event_context *ctx;
12187         struct pmu *pmu;
12188 
12189         perf_swevent_init_cpu(cpu);
12190 
12191         mutex_lock(&pmus_lock);
12192         cpumask_set_cpu(cpu, perf_online_mask);
12193         list_for_each_entry(pmu, &pmus, entry) {
12194                 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12195                 ctx = &cpuctx->ctx;
12196 
12197                 mutex_lock(&ctx->mutex);
12198                 cpuctx->online = 1;
12199                 mutex_unlock(&ctx->mutex);
12200         }
12201         mutex_unlock(&pmus_lock);
12202 
12203         return 0;
12204 }
12205 
12206 int perf_event_exit_cpu(unsigned int cpu)
12207 {
12208         perf_event_exit_cpu_context(cpu);
12209         return 0;
12210 }
12211 
12212 static int
12213 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12214 {
12215         int cpu;
12216 
12217         for_each_online_cpu(cpu)
12218                 perf_event_exit_cpu(cpu);
12219 
12220         return NOTIFY_OK;
12221 }
12222 
12223 /*
12224  * Run the perf reboot notifier at the very last possible moment so that
12225  * the generic watchdog code runs as long as possible.
12226  */
12227 static struct notifier_block perf_reboot_notifier = {
12228         .notifier_call = perf_reboot,
12229         .priority = INT_MIN,
12230 };
12231 
12232 void __init perf_event_init(void)
12233 {
12234         int ret;
12235 
12236         idr_init(&pmu_idr);
12237 
12238         perf_event_init_all_cpus();
12239         init_srcu_struct(&pmus_srcu);
12240         perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12241         perf_pmu_register(&perf_cpu_clock, NULL, -1);
12242         perf_pmu_register(&perf_task_clock, NULL, -1);
12243         perf_tp_register();
12244         perf_event_init_cpu(smp_processor_id());
12245         register_reboot_notifier(&perf_reboot_notifier);
12246 
12247         ret = init_hw_breakpoint();
12248         WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12249 
12250         /*
12251          * Build time assertion that we keep the data_head at the intended
12252          * location.  IOW, validation we got the __reserved[] size right.
12253          */
12254         BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12255                      != 1024);
12256 }
12257 
12258 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12259                               char *page)
12260 {
12261         struct perf_pmu_events_attr *pmu_attr =
12262                 container_of(attr, struct perf_pmu_events_attr, attr);
12263 
12264         if (pmu_attr->event_str)
12265                 return sprintf(page, "%s\n", pmu_attr->event_str);
12266 
12267         return 0;
12268 }
12269 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12270 
12271 static int __init perf_event_sysfs_init(void)
12272 {
12273         struct pmu *pmu;
12274         int ret;
12275 
12276         mutex_lock(&pmus_lock);
12277 
12278         ret = bus_register(&pmu_bus);
12279         if (ret)
12280                 goto unlock;
12281 
12282         list_for_each_entry(pmu, &pmus, entry) {
12283                 if (!pmu->name || pmu->type < 0)
12284                         continue;
12285 
12286                 ret = pmu_dev_alloc(pmu);
12287                 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12288         }
12289         pmu_bus_running = 1;
12290         ret = 0;
12291 
12292 unlock:
12293         mutex_unlock(&pmus_lock);
12294 
12295         return ret;
12296 }
12297 device_initcall(perf_event_sysfs_init);
12298 
12299 #ifdef CONFIG_CGROUP_PERF
12300 static struct cgroup_subsys_state *
12301 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12302 {
12303         struct perf_cgroup *jc;
12304 
12305         jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12306         if (!jc)
12307                 return ERR_PTR(-ENOMEM);
12308 
12309         jc->info = alloc_percpu(struct perf_cgroup_info);
12310         if (!jc->info) {
12311                 kfree(jc);
12312                 return ERR_PTR(-ENOMEM);
12313         }
12314 
12315         return &jc->css;
12316 }
12317 
12318 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12319 {
12320         struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12321 
12322         free_percpu(jc->info);
12323         kfree(jc);
12324 }
12325 
12326 static int __perf_cgroup_move(void *info)
12327 {
12328         struct task_struct *task = info;
12329         rcu_read_lock();
12330         perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12331         rcu_read_unlock();
12332         return 0;
12333 }
12334 
12335 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12336 {
12337         struct task_struct *task;
12338         struct cgroup_subsys_state *css;
12339 
12340         cgroup_taskset_for_each(task, css, tset)
12341                 task_function_call(task, __perf_cgroup_move, task);
12342 }
12343 
12344 struct cgroup_subsys perf_event_cgrp_subsys = {
12345         .css_alloc      = perf_cgroup_css_alloc,
12346         .css_free       = perf_cgroup_css_free,
12347         .attach         = perf_cgroup_attach,
12348         /*
12349          * Implicitly enable on dfl hierarchy so that perf events can
12350          * always be filtered by cgroup2 path as long as perf_event
12351          * controller is not mounted on a legacy hierarchy.
12352          */
12353         .implicit_on_dfl = true,
12354         .threaded       = true,
12355 };
12356 #endif /* CONFIG_CGROUP_PERF */