root/kernel/trace/ftrace.c

DEFINITIONS

1. ftrace_pids_enabled
2. ftrace_ops_init
3. ftrace_pid_func
4. ftrace_sync
5. ftrace_sync_ipi
6. ftrace_ops_get_list_func
7. update_ftrace_function
8. add_ftrace_ops
9. remove_ftrace_ops
10. __register_ftrace_function
11. __unregister_ftrace_function
12. ftrace_update_pid_func
13. function_stat_next
14. function_stat_start
15. function_stat_cmp
16. function_stat_cmp
17. function_stat_headers
18. function_stat_show
19. ftrace_profile_reset
20. ftrace_profile_pages_init
21. ftrace_profile_init_cpu
22. ftrace_profile_init
23. ftrace_find_profiled_func
24. ftrace_add_profile
25. ftrace_profile_alloc
26. function_profile_call
27. ftrace_graph_graph_time_control
28. profile_graph_entry
29. profile_graph_return
30. register_ftrace_profiler
31. unregister_ftrace_profiler
32. register_ftrace_profiler
33. unregister_ftrace_profiler
34. ftrace_profile_write
35. ftrace_profile_read
36. ftrace_profile_tracefs
37. ftrace_profile_tracefs
38. ftrace_ops_trampoline
39. is_ftrace_trampoline
40. ftrace_hash_key
41. __ftrace_lookup_ip
42. ftrace_lookup_ip
43. __add_hash_entry
44. add_hash_entry
45. free_hash_entry
46. remove_hash_entry
47. ftrace_hash_clear
48. free_ftrace_mod
49. clear_ftrace_mod_list
50. free_ftrace_hash
51. __free_ftrace_hash_rcu
52. free_ftrace_hash_rcu
53. ftrace_free_filter
54. alloc_ftrace_hash
55. ftrace_add_mod
56. alloc_and_copy_ftrace_hash
57. __ftrace_hash_move
58. ftrace_hash_move
59. hash_contains_ip
60. ftrace_ops_test
61. ftrace_cmp_recs
62. ftrace_location_range
63. ftrace_location
64. ftrace_text_reserved
65. test_rec_ops_needs_regs
66. __ftrace_hash_rec_update
67. ftrace_hash_rec_disable
68. ftrace_hash_rec_enable
69. ftrace_hash_rec_update_modify
70. ftrace_hash_rec_disable_modify
71. ftrace_hash_rec_enable_modify
72. __ftrace_hash_update_ipmodify
73. ftrace_hash_ipmodify_enable
74. ftrace_hash_ipmodify_disable
75. ftrace_hash_ipmodify_update
76. print_ip_ins
77. print_bug_type
78. ftrace_bug
79. ftrace_check_record
80. ftrace_update_record
81. ftrace_test_record
82. ftrace_find_tramp_ops_any
83. ftrace_find_tramp_ops_next
84. ftrace_find_tramp_ops_curr
85. ftrace_find_tramp_ops_new
86. ftrace_get_addr_new
87. ftrace_get_addr_curr
88. __ftrace_replace_code
89. ftrace_replace_code
90. ftrace_rec_iter_start
91. ftrace_rec_iter_next
92. ftrace_rec_iter_record
93. ftrace_code_disable
94. ftrace_arch_code_modify_prepare
95. ftrace_arch_code_modify_post_process
96. ftrace_modify_all_code
97. __ftrace_modify_code
98. ftrace_run_stop_machine
99. arch_ftrace_update_code
100. ftrace_run_update_code
101. ftrace_run_modify_code
102. arch_ftrace_trampoline_free
103. ftrace_startup_enable
104. ftrace_startup_all
105. ftrace_startup
106. ftrace_shutdown
107. ftrace_startup_sysctl
108. ftrace_shutdown_sysctl
109. ops_traces_mod
110. ops_references_rec
111. ftrace_update_code
112. ftrace_allocate_records
113. ftrace_allocate_pages
114. t_probe_next
115. t_probe_start
116. t_probe_show
117. t_mod_next
118. t_mod_start
119. t_mod_show
120. t_func_next
121. t_next
122. reset_iter_read
123. t_start
124. t_stop
125. arch_ftrace_trampoline_func
126. add_trampoline_func
127. t_show
128. ftrace_avail_open
129. ftrace_enabled_open
130. ftrace_regex_open
131. ftrace_filter_open
132. ftrace_notrace_open
133. arch_ftrace_match_adjust
134. ftrace_match
135. enter_record
136. add_rec_by_index
137. ftrace_match_record
138. match_records
139. ftrace_match_records
140. ftrace_ops_update_code
141. ftrace_hash_move_and_update_ops
142. module_exists
143. cache_mod
144. process_mod_list
145. process_cached_mods
146. ftrace_mod_callback
147. ftrace_mod_cmd_init
148. function_trace_probe_call
149. allocate_ftrace_func_mapper
150. ftrace_func_mapper_find_ip
151. ftrace_func_mapper_add_ip
152. ftrace_func_mapper_remove_ip
153. free_ftrace_func_mapper
154. release_probe
155. acquire_probe_locked
156. register_ftrace_function_probe
157. unregister_ftrace_function_probe_func
158. clear_ftrace_function_probes
159. register_ftrace_command
160. unregister_ftrace_command
161. ftrace_process_regex
162. ftrace_regex_write
163. ftrace_filter_write
164. ftrace_notrace_write
165. ftrace_match_addr
166. ftrace_set_hash
167. ftrace_set_addr
168. ftrace_set_filter_ip
169. ftrace_ops_set_global_filter
170. ftrace_set_regex
171. ftrace_set_filter
172. ftrace_set_notrace
173. ftrace_set_global_filter
174. ftrace_set_global_notrace
175. set_ftrace_notrace
176. set_ftrace_filter
177. set_graph_function
178. set_graph_notrace_function
179. set_graph_max_depth_function
180. set_ftrace_early_graph
181. ftrace_set_early_filter
182. set_ftrace_early_filters
183. ftrace_regex_release
184. __g_next
185. g_next
186. g_start
187. g_stop
188. g_show
189. __ftrace_graph_open
190. ftrace_graph_open
191. ftrace_graph_notrace_open
192. ftrace_graph_release
193. ftrace_graph_set_hash
194. ftrace_graph_write
195. ftrace_create_filter_files
196. ftrace_destroy_filter_files
197. ftrace_init_dyn_tracefs
198. ftrace_cmp_ips
199. ftrace_process_locs
200. referenced_filters
201. clear_mod_from_hash
202. clear_mod_from_hashes
203. ftrace_free_mod_map
204. ftrace_release_mod
205. ftrace_module_enable
206. ftrace_module_init
207. save_ftrace_mod_rec
208. allocate_ftrace_mod_map
209. ftrace_func_address_lookup
210. ftrace_mod_address_lookup
211. ftrace_mod_get_kallsym
212. save_ftrace_mod_rec
213. allocate_ftrace_mod_map
214. clear_func_from_hash
215. clear_func_from_hashes
216. add_to_clear_hash_list
217. ftrace_free_mem
218. ftrace_free_init_mem
219. ftrace_init
220. arch_ftrace_update_trampoline
221. ftrace_update_trampoline
222. ftrace_init_trace_array
223. ftrace_nodyn_init
224. ftrace_init_dyn_tracefs
225. ftrace_startup_enable
226. ftrace_startup_all
227. ftrace_update_trampoline
228. ftrace_init_global_array_ops
229. ftrace_init_array_ops
230. ftrace_reset_array_ops
231. __ftrace_ops_list_func
232. ftrace_ops_list_func
233. ftrace_ops_no_ops
234. ftrace_ops_assist_func
235. ftrace_ops_get_func
236. ftrace_filter_pid_sched_switch_probe
237. ftrace_pid_follow_sched_process_fork
238. ftrace_pid_follow_sched_process_exit
239. ftrace_pid_follow_fork
240. clear_ftrace_pids
241. ftrace_clear_pids
242. ftrace_pid_reset
243. fpid_start
244. fpid_next
245. fpid_stop
246. fpid_show
247. ftrace_pid_open
248. ignore_task_cpu
249. ftrace_pid_write
250. ftrace_pid_release
251. ftrace_init_tracefs
252. ftrace_init_tracefs_toplevel
253. ftrace_kill
254. ftrace_is_dead
255. register_ftrace_function
256. unregister_ftrace_function
257. ftrace_enable_sysctl

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Infrastructure for profiling code inserted by 'gcc -pg'.
   4  *
   5  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   6  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   7  *
   8  * Originally ported from the -rt patch by:
   9  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
  10  *
  11  * Based on code in the latency_tracer, that is:
  12  *
  13  *  Copyright (C) 2004-2006 Ingo Molnar
  14  *  Copyright (C) 2004 Nadia Yvette Chambers
  15  */
  16 
  17 #include <linux/stop_machine.h>
  18 #include <linux/clocksource.h>
  19 #include <linux/sched/task.h>
  20 #include <linux/kallsyms.h>
  21 #include <linux/security.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/tracefs.h>
  24 #include <linux/hardirq.h>
  25 #include <linux/kthread.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/bsearch.h>
  28 #include <linux/module.h>
  29 #include <linux/ftrace.h>
  30 #include <linux/sysctl.h>
  31 #include <linux/slab.h>
  32 #include <linux/ctype.h>
  33 #include <linux/sort.h>
  34 #include <linux/list.h>
  35 #include <linux/hash.h>
  36 #include <linux/rcupdate.h>
  37 #include <linux/kprobes.h>
  38 
  39 #include <trace/events/sched.h>
  40 
  41 #include <asm/sections.h>
  42 #include <asm/setup.h>
  43 
  44 #include "ftrace_internal.h"
  45 #include "trace_output.h"
  46 #include "trace_stat.h"
  47 
  48 #define FTRACE_WARN_ON(cond)                    \
  49         ({                                      \
  50                 int ___r = cond;                \
  51                 if (WARN_ON(___r))              \
  52                         ftrace_kill();          \
  53                 ___r;                           \
  54         })
  55 
  56 #define FTRACE_WARN_ON_ONCE(cond)               \
  57         ({                                      \
  58                 int ___r = cond;                \
  59                 if (WARN_ON_ONCE(___r))         \
  60                         ftrace_kill();          \
  61                 ___r;                           \
  62         })
  63 
  64 /* hash bits for specific function selection */
  65 #define FTRACE_HASH_BITS 7
  66 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  67 #define FTRACE_HASH_DEFAULT_BITS 10
  68 #define FTRACE_HASH_MAX_BITS 12
  69 
  70 #ifdef CONFIG_DYNAMIC_FTRACE
  71 #define INIT_OPS_HASH(opsname)  \
  72         .func_hash              = &opsname.local_hash,                  \
  73         .local_hash.regex_lock  = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
  74 #else
  75 #define INIT_OPS_HASH(opsname)
  76 #endif
  77 
  78 enum {
  79         FTRACE_MODIFY_ENABLE_FL         = (1 << 0),
  80         FTRACE_MODIFY_MAY_SLEEP_FL      = (1 << 1),
  81 };
  82 
  83 struct ftrace_ops ftrace_list_end __read_mostly = {
  84         .func           = ftrace_stub,
  85         .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
  86         INIT_OPS_HASH(ftrace_list_end)
  87 };
  88 
  89 /* ftrace_enabled is a method to turn ftrace on or off */
  90 int ftrace_enabled __read_mostly;
  91 static int last_ftrace_enabled;
  92 
  93 /* Current function tracing op */
  94 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
  95 /* What to set function_trace_op to */
  96 static struct ftrace_ops *set_function_trace_op;
  97 
  98 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
  99 {
 100         struct trace_array *tr;
 101 
 102         if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
 103                 return false;
 104 
 105         tr = ops->private;
 106 
 107         return tr->function_pids != NULL;
 108 }
 109 
 110 static void ftrace_update_trampoline(struct ftrace_ops *ops);
 111 
 112 /*
 113  * ftrace_disabled is set when an anomaly is discovered.
 114  * ftrace_disabled is much stronger than ftrace_enabled.
 115  */
 116 static int ftrace_disabled __read_mostly;
 117 
 118 DEFINE_MUTEX(ftrace_lock);
 119 
 120 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
 121 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 122 struct ftrace_ops global_ops;
 123 
 124 #if ARCH_SUPPORTS_FTRACE_OPS
 125 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 126                                  struct ftrace_ops *op, struct pt_regs *regs);
 127 #else
 128 /* See comment below, where ftrace_ops_list_func is defined */
 129 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
 130 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
 131 #endif
 132 
 133 static inline void ftrace_ops_init(struct ftrace_ops *ops)
 134 {
 135 #ifdef CONFIG_DYNAMIC_FTRACE
 136         if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
 137                 mutex_init(&ops->local_hash.regex_lock);
 138                 ops->func_hash = &ops->local_hash;
 139                 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
 140         }
 141 #endif
 142 }
 143 
 144 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
 145                             struct ftrace_ops *op, struct pt_regs *regs)
 146 {
 147         struct trace_array *tr = op->private;
 148 
 149         if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
 150                 return;
 151 
 152         op->saved_func(ip, parent_ip, op, regs);
 153 }
 154 
 155 static void ftrace_sync(struct work_struct *work)
 156 {
 157         /*
 158          * This function is just a stub to implement a hard force
 159          * of synchronize_rcu(). This requires synchronizing
 160          * tasks even in userspace and idle.
 161          *
 162          * Yes, function tracing is rude.
 163          */
 164 }
 165 
 166 static void ftrace_sync_ipi(void *data)
 167 {
 168         /* Probably not needed, but do it anyway */
 169         smp_rmb();
 170 }
 171 
 172 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
 173 {
 174         /*
 175          * If this is a dynamic, RCU, or per CPU ops, or we force list func,
 176          * then it needs to call the list anyway.
 177          */
 178         if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
 179             FTRACE_FORCE_LIST_FUNC)
 180                 return ftrace_ops_list_func;
 181 
 182         return ftrace_ops_get_func(ops);
 183 }
 184 
 185 static void update_ftrace_function(void)
 186 {
 187         ftrace_func_t func;
 188 
 189         /*
 190          * Prepare the ftrace_ops that the arch callback will use.
 191          * If there's only one ftrace_ops registered, the ftrace_ops_list
 192          * will point to the ops we want.
 193          */
 194         set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
 195                                                 lockdep_is_held(&ftrace_lock));
 196 
 197         /* If there's no ftrace_ops registered, just call the stub function */
 198         if (set_function_trace_op == &ftrace_list_end) {
 199                 func = ftrace_stub;
 200 
 201         /*
 202          * If we are at the end of the list and this ops is
 203          * recursion safe and not dynamic and the arch supports passing ops,
 204          * then have the mcount trampoline call the function directly.
 205          */
 206         } else if (rcu_dereference_protected(ftrace_ops_list->next,
 207                         lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
 208                 func = ftrace_ops_get_list_func(ftrace_ops_list);
 209 
 210         } else {
 211                 /* Just use the default ftrace_ops */
 212                 set_function_trace_op = &ftrace_list_end;
 213                 func = ftrace_ops_list_func;
 214         }
 215 
 216         update_function_graph_func();
 217 
 218         /* If there's no change, then do nothing more here */
 219         if (ftrace_trace_function == func)
 220                 return;
 221 
 222         /*
 223          * If we are using the list function, it doesn't care
 224          * about the function_trace_ops.
 225          */
 226         if (func == ftrace_ops_list_func) {
 227                 ftrace_trace_function = func;
 228                 /*
 229                  * Don't even bother setting function_trace_ops,
 230                  * it would be racy to do so anyway.
 231                  */
 232                 return;
 233         }
 234 
 235 #ifndef CONFIG_DYNAMIC_FTRACE
 236         /*
 237          * For static tracing, we need to be a bit more careful.
 238          * The function change takes affect immediately. Thus,
 239          * we need to coorditate the setting of the function_trace_ops
 240          * with the setting of the ftrace_trace_function.
 241          *
 242          * Set the function to the list ops, which will call the
 243          * function we want, albeit indirectly, but it handles the
 244          * ftrace_ops and doesn't depend on function_trace_op.
 245          */
 246         ftrace_trace_function = ftrace_ops_list_func;
 247         /*
 248          * Make sure all CPUs see this. Yes this is slow, but static
 249          * tracing is slow and nasty to have enabled.
 250          */
 251         schedule_on_each_cpu(ftrace_sync);
 252         /* Now all cpus are using the list ops. */
 253         function_trace_op = set_function_trace_op;
 254         /* Make sure the function_trace_op is visible on all CPUs */
 255         smp_wmb();
 256         /* Nasty way to force a rmb on all cpus */
 257         smp_call_function(ftrace_sync_ipi, NULL, 1);
 258         /* OK, we are all set to update the ftrace_trace_function now! */
 259 #endif /* !CONFIG_DYNAMIC_FTRACE */
 260 
 261         ftrace_trace_function = func;
 262 }
 263 
 264 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
 265                            struct ftrace_ops *ops)
 266 {
 267         rcu_assign_pointer(ops->next, *list);
 268 
 269         /*
 270          * We are entering ops into the list but another
 271          * CPU might be walking that list. We need to make sure
 272          * the ops->next pointer is valid before another CPU sees
 273          * the ops pointer included into the list.
 274          */
 275         rcu_assign_pointer(*list, ops);
 276 }
 277 
 278 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
 279                              struct ftrace_ops *ops)
 280 {
 281         struct ftrace_ops **p;
 282 
 283         /*
 284          * If we are removing the last function, then simply point
 285          * to the ftrace_stub.
 286          */
 287         if (rcu_dereference_protected(*list,
 288                         lockdep_is_held(&ftrace_lock)) == ops &&
 289             rcu_dereference_protected(ops->next,
 290                         lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
 291                 *list = &ftrace_list_end;
 292                 return 0;
 293         }
 294 
 295         for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
 296                 if (*p == ops)
 297                         break;
 298 
 299         if (*p != ops)
 300                 return -1;
 301 
 302         *p = (*p)->next;
 303         return 0;
 304 }
 305 
 306 static void ftrace_update_trampoline(struct ftrace_ops *ops);
 307 
 308 int __register_ftrace_function(struct ftrace_ops *ops)
 309 {
 310         if (ops->flags & FTRACE_OPS_FL_DELETED)
 311                 return -EINVAL;
 312 
 313         if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
 314                 return -EBUSY;
 315 
 316 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 317         /*
 318          * If the ftrace_ops specifies SAVE_REGS, then it only can be used
 319          * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
 320          * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
 321          */
 322         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
 323             !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
 324                 return -EINVAL;
 325 
 326         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
 327                 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
 328 #endif
 329 
 330         if (!core_kernel_data((unsigned long)ops))
 331                 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 332 
 333         add_ftrace_ops(&ftrace_ops_list, ops);
 334 
 335         /* Always save the function, and reset at unregistering */
 336         ops->saved_func = ops->func;
 337 
 338         if (ftrace_pids_enabled(ops))
 339                 ops->func = ftrace_pid_func;
 340 
 341         ftrace_update_trampoline(ops);
 342 
 343         if (ftrace_enabled)
 344                 update_ftrace_function();
 345 
 346         return 0;
 347 }
 348 
 349 int __unregister_ftrace_function(struct ftrace_ops *ops)
 350 {
 351         int ret;
 352 
 353         if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 354                 return -EBUSY;
 355 
 356         ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 357 
 358         if (ret < 0)
 359                 return ret;
 360 
 361         if (ftrace_enabled)
 362                 update_ftrace_function();
 363 
 364         ops->func = ops->saved_func;
 365 
 366         return 0;
 367 }
 368 
 369 static void ftrace_update_pid_func(void)
 370 {
 371         struct ftrace_ops *op;
 372 
 373         /* Only do something if we are tracing something */
 374         if (ftrace_trace_function == ftrace_stub)
 375                 return;
 376 
 377         do_for_each_ftrace_op(op, ftrace_ops_list) {
 378                 if (op->flags & FTRACE_OPS_FL_PID) {
 379                         op->func = ftrace_pids_enabled(op) ?
 380                                 ftrace_pid_func : op->saved_func;
 381                         ftrace_update_trampoline(op);
 382                 }
 383         } while_for_each_ftrace_op(op);
 384 
 385         update_ftrace_function();
 386 }
 387 
 388 #ifdef CONFIG_FUNCTION_PROFILER
 389 struct ftrace_profile {
 390         struct hlist_node               node;
 391         unsigned long                   ip;
 392         unsigned long                   counter;
 393 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 394         unsigned long long              time;
 395         unsigned long long              time_squared;
 396 #endif
 397 };
 398 
 399 struct ftrace_profile_page {
 400         struct ftrace_profile_page      *next;
 401         unsigned long                   index;
 402         struct ftrace_profile           records[];
 403 };
 404 
 405 struct ftrace_profile_stat {
 406         atomic_t                        disabled;
 407         struct hlist_head               *hash;
 408         struct ftrace_profile_page      *pages;
 409         struct ftrace_profile_page      *start;
 410         struct tracer_stat              stat;
 411 };
 412 
 413 #define PROFILE_RECORDS_SIZE                                            \
 414         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 415 
 416 #define PROFILES_PER_PAGE                                       \
 417         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 418 
 419 static int ftrace_profile_enabled __read_mostly;
 420 
 421 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 422 static DEFINE_MUTEX(ftrace_profile_lock);
 423 
 424 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 425 
 426 #define FTRACE_PROFILE_HASH_BITS 10
 427 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
 428 
 429 static void *
 430 function_stat_next(void *v, int idx)
 431 {
 432         struct ftrace_profile *rec = v;
 433         struct ftrace_profile_page *pg;
 434 
 435         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 436 
 437  again:
 438         if (idx != 0)
 439                 rec++;
 440 
 441         if ((void *)rec >= (void *)&pg->records[pg->index]) {
 442                 pg = pg->next;
 443                 if (!pg)
 444                         return NULL;
 445                 rec = &pg->records[0];
 446                 if (!rec->counter)
 447                         goto again;
 448         }
 449 
 450         return rec;
 451 }
 452 
 453 static void *function_stat_start(struct tracer_stat *trace)
 454 {
 455         struct ftrace_profile_stat *stat =
 456                 container_of(trace, struct ftrace_profile_stat, stat);
 457 
 458         if (!stat || !stat->start)
 459                 return NULL;
 460 
 461         return function_stat_next(&stat->start->records[0], 0);
 462 }
 463 
 464 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 465 /* function graph compares on total time */
 466 static int function_stat_cmp(void *p1, void *p2)
 467 {
 468         struct ftrace_profile *a = p1;
 469         struct ftrace_profile *b = p2;
 470 
 471         if (a->time < b->time)
 472                 return -1;
 473         if (a->time > b->time)
 474                 return 1;
 475         else
 476                 return 0;
 477 }
 478 #else
 479 /* not function graph compares against hits */
 480 static int function_stat_cmp(void *p1, void *p2)
 481 {
 482         struct ftrace_profile *a = p1;
 483         struct ftrace_profile *b = p2;
 484 
 485         if (a->counter < b->counter)
 486                 return -1;
 487         if (a->counter > b->counter)
 488                 return 1;
 489         else
 490                 return 0;
 491 }
 492 #endif
 493 
 494 static int function_stat_headers(struct seq_file *m)
 495 {
 496 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 497         seq_puts(m, "  Function                               "
 498                  "Hit    Time            Avg             s^2\n"
 499                     "  --------                               "
 500                  "---    ----            ---             ---\n");
 501 #else
 502         seq_puts(m, "  Function                               Hit\n"
 503                     "  --------                               ---\n");
 504 #endif
 505         return 0;
 506 }
 507 
 508 static int function_stat_show(struct seq_file *m, void *v)
 509 {
 510         struct ftrace_profile *rec = v;
 511         char str[KSYM_SYMBOL_LEN];
 512         int ret = 0;
 513 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 514         static struct trace_seq s;
 515         unsigned long long avg;
 516         unsigned long long stddev;
 517 #endif
 518         mutex_lock(&ftrace_profile_lock);
 519 
 520         /* we raced with function_profile_reset() */
 521         if (unlikely(rec->counter == 0)) {
 522                 ret = -EBUSY;
 523                 goto out;
 524         }
 525 
 526 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 527         avg = div64_ul(rec->time, rec->counter);
 528         if (tracing_thresh && (avg < tracing_thresh))
 529                 goto out;
 530 #endif
 531 
 532         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 533         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 534 
 535 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 536         seq_puts(m, "    ");
 537 
 538         /* Sample standard deviation (s^2) */
 539         if (rec->counter <= 1)
 540                 stddev = 0;
 541         else {
 542                 /*
 543                  * Apply Welford's method:
 544                  * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
 545                  */
 546                 stddev = rec->counter * rec->time_squared -
 547                          rec->time * rec->time;
 548 
 549                 /*
 550                  * Divide only 1000 for ns^2 -> us^2 conversion.
 551                  * trace_print_graph_duration will divide 1000 again.
 552                  */
 553                 stddev = div64_ul(stddev,
 554                                   rec->counter * (rec->counter - 1) * 1000);
 555         }
 556 
 557         trace_seq_init(&s);
 558         trace_print_graph_duration(rec->time, &s);
 559         trace_seq_puts(&s, "    ");
 560         trace_print_graph_duration(avg, &s);
 561         trace_seq_puts(&s, "    ");
 562         trace_print_graph_duration(stddev, &s);
 563         trace_print_seq(m, &s);
 564 #endif
 565         seq_putc(m, '\n');
 566 out:
 567         mutex_unlock(&ftrace_profile_lock);
 568 
 569         return ret;
 570 }
 571 
 572 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 573 {
 574         struct ftrace_profile_page *pg;
 575 
 576         pg = stat->pages = stat->start;
 577 
 578         while (pg) {
 579                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 580                 pg->index = 0;
 581                 pg = pg->next;
 582         }
 583 
 584         memset(stat->hash, 0,
 585                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 586 }
 587 
 588 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 589 {
 590         struct ftrace_profile_page *pg;
 591         int functions;
 592         int pages;
 593         int i;
 594 
 595         /* If we already allocated, do nothing */
 596         if (stat->pages)
 597                 return 0;
 598 
 599         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 600         if (!stat->pages)
 601                 return -ENOMEM;
 602 
 603 #ifdef CONFIG_DYNAMIC_FTRACE
 604         functions = ftrace_update_tot_cnt;
 605 #else
 606         /*
 607          * We do not know the number of functions that exist because
 608          * dynamic tracing is what counts them. With past experience
 609          * we have around 20K functions. That should be more than enough.
 610          * It is highly unlikely we will execute every function in
 611          * the kernel.
 612          */
 613         functions = 20000;
 614 #endif
 615 
 616         pg = stat->start = stat->pages;
 617 
 618         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 619 
 620         for (i = 1; i < pages; i++) {
 621                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 622                 if (!pg->next)
 623                         goto out_free;
 624                 pg = pg->next;
 625         }
 626 
 627         return 0;
 628 
 629  out_free:
 630         pg = stat->start;
 631         while (pg) {
 632                 unsigned long tmp = (unsigned long)pg;
 633 
 634                 pg = pg->next;
 635                 free_page(tmp);
 636         }
 637 
 638         stat->pages = NULL;
 639         stat->start = NULL;
 640 
 641         return -ENOMEM;
 642 }
 643 
 644 static int ftrace_profile_init_cpu(int cpu)
 645 {
 646         struct ftrace_profile_stat *stat;
 647         int size;
 648 
 649         stat = &per_cpu(ftrace_profile_stats, cpu);
 650 
 651         if (stat->hash) {
 652                 /* If the profile is already created, simply reset it */
 653                 ftrace_profile_reset(stat);
 654                 return 0;
 655         }
 656 
 657         /*
 658          * We are profiling all functions, but usually only a few thousand
 659          * functions are hit. We'll make a hash of 1024 items.
 660          */
 661         size = FTRACE_PROFILE_HASH_SIZE;
 662 
 663         stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
 664 
 665         if (!stat->hash)
 666                 return -ENOMEM;
 667 
 668         /* Preallocate the function profiling pages */
 669         if (ftrace_profile_pages_init(stat) < 0) {
 670                 kfree(stat->hash);
 671                 stat->hash = NULL;
 672                 return -ENOMEM;
 673         }
 674 
 675         return 0;
 676 }
 677 
 678 static int ftrace_profile_init(void)
 679 {
 680         int cpu;
 681         int ret = 0;
 682 
 683         for_each_possible_cpu(cpu) {
 684                 ret = ftrace_profile_init_cpu(cpu);
 685                 if (ret)
 686                         break;
 687         }
 688 
 689         return ret;
 690 }
 691 
 692 /* interrupts must be disabled */
 693 static struct ftrace_profile *
 694 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 695 {
 696         struct ftrace_profile *rec;
 697         struct hlist_head *hhd;
 698         unsigned long key;
 699 
 700         key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
 701         hhd = &stat->hash[key];
 702 
 703         if (hlist_empty(hhd))
 704                 return NULL;
 705 
 706         hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
 707                 if (rec->ip == ip)
 708                         return rec;
 709         }
 710 
 711         return NULL;
 712 }
 713 
 714 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 715                                struct ftrace_profile *rec)
 716 {
 717         unsigned long key;
 718 
 719         key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
 720         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 721 }
 722 
 723 /*
 724  * The memory is already allocated, this simply finds a new record to use.
 725  */
 726 static struct ftrace_profile *
 727 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 728 {
 729         struct ftrace_profile *rec = NULL;
 730 
 731         /* prevent recursion (from NMIs) */
 732         if (atomic_inc_return(&stat->disabled) != 1)
 733                 goto out;
 734 
 735         /*
 736          * Try to find the function again since an NMI
 737          * could have added it
 738          */
 739         rec = ftrace_find_profiled_func(stat, ip);
 740         if (rec)
 741                 goto out;
 742 
 743         if (stat->pages->index == PROFILES_PER_PAGE) {
 744                 if (!stat->pages->next)
 745                         goto out;
 746                 stat->pages = stat->pages->next;
 747         }
 748 
 749         rec = &stat->pages->records[stat->pages->index++];
 750         rec->ip = ip;
 751         ftrace_add_profile(stat, rec);
 752 
 753  out:
 754         atomic_dec(&stat->disabled);
 755 
 756         return rec;
 757 }
 758 
 759 static void
 760 function_profile_call(unsigned long ip, unsigned long parent_ip,
 761                       struct ftrace_ops *ops, struct pt_regs *regs)
 762 {
 763         struct ftrace_profile_stat *stat;
 764         struct ftrace_profile *rec;
 765         unsigned long flags;
 766 
 767         if (!ftrace_profile_enabled)
 768                 return;
 769 
 770         local_irq_save(flags);
 771 
 772         stat = this_cpu_ptr(&ftrace_profile_stats);
 773         if (!stat->hash || !ftrace_profile_enabled)
 774                 goto out;
 775 
 776         rec = ftrace_find_profiled_func(stat, ip);
 777         if (!rec) {
 778                 rec = ftrace_profile_alloc(stat, ip);
 779                 if (!rec)
 780                         goto out;
 781         }
 782 
 783         rec->counter++;
 784  out:
 785         local_irq_restore(flags);
 786 }
 787 
 788 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 789 static bool fgraph_graph_time = true;
 790 
 791 void ftrace_graph_graph_time_control(bool enable)
 792 {
 793         fgraph_graph_time = enable;
 794 }
 795 
 796 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 797 {
 798         struct ftrace_ret_stack *ret_stack;
 799 
 800         function_profile_call(trace->func, 0, NULL, NULL);
 801 
 802         /* If function graph is shutting down, ret_stack can be NULL */
 803         if (!current->ret_stack)
 804                 return 0;
 805 
 806         ret_stack = ftrace_graph_get_ret_stack(current, 0);
 807         if (ret_stack)
 808                 ret_stack->subtime = 0;
 809 
 810         return 1;
 811 }
 812 
 813 static void profile_graph_return(struct ftrace_graph_ret *trace)
 814 {
 815         struct ftrace_ret_stack *ret_stack;
 816         struct ftrace_profile_stat *stat;
 817         unsigned long long calltime;
 818         struct ftrace_profile *rec;
 819         unsigned long flags;
 820 
 821         local_irq_save(flags);
 822         stat = this_cpu_ptr(&ftrace_profile_stats);
 823         if (!stat->hash || !ftrace_profile_enabled)
 824                 goto out;
 825 
 826         /* If the calltime was zero'd ignore it */
 827         if (!trace->calltime)
 828                 goto out;
 829 
 830         calltime = trace->rettime - trace->calltime;
 831 
 832         if (!fgraph_graph_time) {
 833 
 834                 /* Append this call time to the parent time to subtract */
 835                 ret_stack = ftrace_graph_get_ret_stack(current, 1);
 836                 if (ret_stack)
 837                         ret_stack->subtime += calltime;
 838 
 839                 ret_stack = ftrace_graph_get_ret_stack(current, 0);
 840                 if (ret_stack && ret_stack->subtime < calltime)
 841                         calltime -= ret_stack->subtime;
 842                 else
 843                         calltime = 0;
 844         }
 845 
 846         rec = ftrace_find_profiled_func(stat, trace->func);
 847         if (rec) {
 848                 rec->time += calltime;
 849                 rec->time_squared += calltime * calltime;
 850         }
 851 
 852  out:
 853         local_irq_restore(flags);
 854 }
 855 
 856 static struct fgraph_ops fprofiler_ops = {
 857         .entryfunc = &profile_graph_entry,
 858         .retfunc = &profile_graph_return,
 859 };
 860 
 861 static int register_ftrace_profiler(void)
 862 {
 863         return register_ftrace_graph(&fprofiler_ops);
 864 }
 865 
 866 static void unregister_ftrace_profiler(void)
 867 {
 868         unregister_ftrace_graph(&fprofiler_ops);
 869 }
 870 #else
 871 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 872         .func           = function_profile_call,
 873         .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
 874         INIT_OPS_HASH(ftrace_profile_ops)
 875 };
 876 
 877 static int register_ftrace_profiler(void)
 878 {
 879         return register_ftrace_function(&ftrace_profile_ops);
 880 }
 881 
 882 static void unregister_ftrace_profiler(void)
 883 {
 884         unregister_ftrace_function(&ftrace_profile_ops);
 885 }
 886 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 887 
 888 static ssize_t
 889 ftrace_profile_write(struct file *filp, const char __user *ubuf,
 890                      size_t cnt, loff_t *ppos)
 891 {
 892         unsigned long val;
 893         int ret;
 894 
 895         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 896         if (ret)
 897                 return ret;
 898 
 899         val = !!val;
 900 
 901         mutex_lock(&ftrace_profile_lock);
 902         if (ftrace_profile_enabled ^ val) {
 903                 if (val) {
 904                         ret = ftrace_profile_init();
 905                         if (ret < 0) {
 906                                 cnt = ret;
 907                                 goto out;
 908                         }
 909 
 910                         ret = register_ftrace_profiler();
 911                         if (ret < 0) {
 912                                 cnt = ret;
 913                                 goto out;
 914                         }
 915                         ftrace_profile_enabled = 1;
 916                 } else {
 917                         ftrace_profile_enabled = 0;
 918                         /*
 919                          * unregister_ftrace_profiler calls stop_machine
 920                          * so this acts like an synchronize_rcu.
 921                          */
 922                         unregister_ftrace_profiler();
 923                 }
 924         }
 925  out:
 926         mutex_unlock(&ftrace_profile_lock);
 927 
 928         *ppos += cnt;
 929 
 930         return cnt;
 931 }
 932 
 933 static ssize_t
 934 ftrace_profile_read(struct file *filp, char __user *ubuf,
 935                      size_t cnt, loff_t *ppos)
 936 {
 937         char buf[64];           /* big enough to hold a number */
 938         int r;
 939 
 940         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 941         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 942 }
 943 
 944 static const struct file_operations ftrace_profile_fops = {
 945         .open           = tracing_open_generic,
 946         .read           = ftrace_profile_read,
 947         .write          = ftrace_profile_write,
 948         .llseek         = default_llseek,
 949 };
 950 
 951 /* used to initialize the real stat files */
 952 static struct tracer_stat function_stats __initdata = {
 953         .name           = "functions",
 954         .stat_start     = function_stat_start,
 955         .stat_next      = function_stat_next,
 956         .stat_cmp       = function_stat_cmp,
 957         .stat_headers   = function_stat_headers,
 958         .stat_show      = function_stat_show
 959 };
 960 
 961 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 962 {
 963         struct ftrace_profile_stat *stat;
 964         struct dentry *entry;
 965         char *name;
 966         int ret;
 967         int cpu;
 968 
 969         for_each_possible_cpu(cpu) {
 970                 stat = &per_cpu(ftrace_profile_stats, cpu);
 971 
 972                 name = kasprintf(GFP_KERNEL, "function%d", cpu);
 973                 if (!name) {
 974                         /*
 975                          * The files created are permanent, if something happens
 976                          * we still do not free memory.
 977                          */
 978                         WARN(1,
 979                              "Could not allocate stat file for cpu %d\n",
 980                              cpu);
 981                         return;
 982                 }
 983                 stat->stat = function_stats;
 984                 stat->stat.name = name;
 985                 ret = register_stat_tracer(&stat->stat);
 986                 if (ret) {
 987                         WARN(1,
 988                              "Could not register function stat for cpu %d\n",
 989                              cpu);
 990                         kfree(name);
 991                         return;
 992                 }
 993         }
 994 
 995         entry = tracefs_create_file("function_profile_enabled", 0644,
 996                                     d_tracer, NULL, &ftrace_profile_fops);
 997         if (!entry)
 998                 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
 999 }
1000 
1001 #else /* CONFIG_FUNCTION_PROFILER */
1002 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1003 {
1004 }
1005 #endif /* CONFIG_FUNCTION_PROFILER */
1006 
1007 #ifdef CONFIG_DYNAMIC_FTRACE
1008 
1009 static struct ftrace_ops *removed_ops;
1010 
1011 /*
1012  * Set when doing a global update, like enabling all recs or disabling them.
1013  * It is not set when just updating a single ftrace_ops.
1014  */
1015 static bool update_all_ops;
1016 
1017 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1018 # error Dynamic ftrace depends on MCOUNT_RECORD
1019 #endif
1020 
1021 struct ftrace_func_entry {
1022         struct hlist_node hlist;
1023         unsigned long ip;
1024 };
1025 
1026 struct ftrace_func_probe {
1027         struct ftrace_probe_ops *probe_ops;
1028         struct ftrace_ops       ops;
1029         struct trace_array      *tr;
1030         struct list_head        list;
1031         void                    *data;
1032         int                     ref;
1033 };
1034 
1035 /*
1036  * We make these constant because no one should touch them,
1037  * but they are used as the default "empty hash", to avoid allocating
1038  * it all the time. These are in a read only section such that if
1039  * anyone does try to modify it, it will cause an exception.
1040  */
1041 static const struct hlist_head empty_buckets[1];
1042 static const struct ftrace_hash empty_hash = {
1043         .buckets = (struct hlist_head *)empty_buckets,
1044 };
1045 #define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)
1046 
1047 struct ftrace_ops global_ops = {
1048         .func                           = ftrace_stub,
1049         .local_hash.notrace_hash        = EMPTY_HASH,
1050         .local_hash.filter_hash         = EMPTY_HASH,
1051         INIT_OPS_HASH(global_ops)
1052         .flags                          = FTRACE_OPS_FL_RECURSION_SAFE |
1053                                           FTRACE_OPS_FL_INITIALIZED |
1054                                           FTRACE_OPS_FL_PID,
1055 };
1056 
1057 /*
1058  * Used by the stack undwinder to know about dynamic ftrace trampolines.
1059  */
1060 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1061 {
1062         struct ftrace_ops *op = NULL;
1063 
1064         /*
1065          * Some of the ops may be dynamically allocated,
1066          * they are freed after a synchronize_rcu().
1067          */
1068         preempt_disable_notrace();
1069 
1070         do_for_each_ftrace_op(op, ftrace_ops_list) {
1071                 /*
1072                  * This is to check for dynamically allocated trampolines.
1073                  * Trampolines that are in kernel text will have
1074                  * core_kernel_text() return true.
1075                  */
1076                 if (op->trampoline && op->trampoline_size)
1077                         if (addr >= op->trampoline &&
1078                             addr < op->trampoline + op->trampoline_size) {
1079                                 preempt_enable_notrace();
1080                                 return op;
1081                         }
1082         } while_for_each_ftrace_op(op);
1083         preempt_enable_notrace();
1084 
1085         return NULL;
1086 }
1087 
1088 /*
1089  * This is used by __kernel_text_address() to return true if the
1090  * address is on a dynamically allocated trampoline that would
1091  * not return true for either core_kernel_text() or
1092  * is_module_text_address().
1093  */
1094 bool is_ftrace_trampoline(unsigned long addr)
1095 {
1096         return ftrace_ops_trampoline(addr) != NULL;
1097 }
1098 
1099 struct ftrace_page {
1100         struct ftrace_page      *next;
1101         struct dyn_ftrace       *records;
1102         int                     index;
1103         int                     size;
1104 };
1105 
1106 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1107 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1108 
1109 /* estimate from running different kernels */
1110 #define NR_TO_INIT              10000
1111 
1112 static struct ftrace_page       *ftrace_pages_start;
1113 static struct ftrace_page       *ftrace_pages;
1114 
1115 static __always_inline unsigned long
1116 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1117 {
1118         if (hash->size_bits > 0)
1119                 return hash_long(ip, hash->size_bits);
1120 
1121         return 0;
1122 }
1123 
1124 /* Only use this function if ftrace_hash_empty() has already been tested */
1125 static __always_inline struct ftrace_func_entry *
1126 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1127 {
1128         unsigned long key;
1129         struct ftrace_func_entry *entry;
1130         struct hlist_head *hhd;
1131 
1132         key = ftrace_hash_key(hash, ip);
1133         hhd = &hash->buckets[key];
1134 
1135         hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1136                 if (entry->ip == ip)
1137                         return entry;
1138         }
1139         return NULL;
1140 }
1141 
1142 /**
1143  * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1144  * @hash: The hash to look at
1145  * @ip: The instruction pointer to test
1146  *
1147  * Search a given @hash to see if a given instruction pointer (@ip)
1148  * exists in it.
1149  *
1150  * Returns the entry that holds the @ip if found. NULL otherwise.
1151  */
1152 struct ftrace_func_entry *
1153 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1154 {
1155         if (ftrace_hash_empty(hash))
1156                 return NULL;
1157 
1158         return __ftrace_lookup_ip(hash, ip);
1159 }
1160 
1161 static void __add_hash_entry(struct ftrace_hash *hash,
1162                              struct ftrace_func_entry *entry)
1163 {
1164         struct hlist_head *hhd;
1165         unsigned long key;
1166 
1167         key = ftrace_hash_key(hash, entry->ip);
1168         hhd = &hash->buckets[key];
1169         hlist_add_head(&entry->hlist, hhd);
1170         hash->count++;
1171 }
1172 
1173 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1174 {
1175         struct ftrace_func_entry *entry;
1176 
1177         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1178         if (!entry)
1179                 return -ENOMEM;
1180 
1181         entry->ip = ip;
1182         __add_hash_entry(hash, entry);
1183 
1184         return 0;
1185 }
1186 
1187 static void
1188 free_hash_entry(struct ftrace_hash *hash,
1189                   struct ftrace_func_entry *entry)
1190 {
1191         hlist_del(&entry->hlist);
1192         kfree(entry);
1193         hash->count--;
1194 }
1195 
1196 static void
1197 remove_hash_entry(struct ftrace_hash *hash,
1198                   struct ftrace_func_entry *entry)
1199 {
1200         hlist_del_rcu(&entry->hlist);
1201         hash->count--;
1202 }
1203 
1204 static void ftrace_hash_clear(struct ftrace_hash *hash)
1205 {
1206         struct hlist_head *hhd;
1207         struct hlist_node *tn;
1208         struct ftrace_func_entry *entry;
1209         int size = 1 << hash->size_bits;
1210         int i;
1211 
1212         if (!hash->count)
1213                 return;
1214 
1215         for (i = 0; i < size; i++) {
1216                 hhd = &hash->buckets[i];
1217                 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1218                         free_hash_entry(hash, entry);
1219         }
1220         FTRACE_WARN_ON(hash->count);
1221 }
1222 
1223 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1224 {
1225         list_del(&ftrace_mod->list);
1226         kfree(ftrace_mod->module);
1227         kfree(ftrace_mod->func);
1228         kfree(ftrace_mod);
1229 }
1230 
1231 static void clear_ftrace_mod_list(struct list_head *head)
1232 {
1233         struct ftrace_mod_load *p, *n;
1234 
1235         /* stack tracer isn't supported yet */
1236         if (!head)
1237                 return;
1238 
1239         mutex_lock(&ftrace_lock);
1240         list_for_each_entry_safe(p, n, head, list)
1241                 free_ftrace_mod(p);
1242         mutex_unlock(&ftrace_lock);
1243 }
1244 
1245 static void free_ftrace_hash(struct ftrace_hash *hash)
1246 {
1247         if (!hash || hash == EMPTY_HASH)
1248                 return;
1249         ftrace_hash_clear(hash);
1250         kfree(hash->buckets);
1251         kfree(hash);
1252 }
1253 
1254 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1255 {
1256         struct ftrace_hash *hash;
1257 
1258         hash = container_of(rcu, struct ftrace_hash, rcu);
1259         free_ftrace_hash(hash);
1260 }
1261 
1262 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1263 {
1264         if (!hash || hash == EMPTY_HASH)
1265                 return;
1266         call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1267 }
1268 
1269 void ftrace_free_filter(struct ftrace_ops *ops)
1270 {
1271         ftrace_ops_init(ops);
1272         free_ftrace_hash(ops->func_hash->filter_hash);
1273         free_ftrace_hash(ops->func_hash->notrace_hash);
1274 }
1275 
1276 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1277 {
1278         struct ftrace_hash *hash;
1279         int size;
1280 
1281         hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1282         if (!hash)
1283                 return NULL;
1284 
1285         size = 1 << size_bits;
1286         hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1287 
1288         if (!hash->buckets) {
1289                 kfree(hash);
1290                 return NULL;
1291         }
1292 
1293         hash->size_bits = size_bits;
1294 
1295         return hash;
1296 }
1297 
1298 
1299 static int ftrace_add_mod(struct trace_array *tr,
1300                           const char *func, const char *module,
1301                           int enable)
1302 {
1303         struct ftrace_mod_load *ftrace_mod;
1304         struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1305 
1306         ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1307         if (!ftrace_mod)
1308                 return -ENOMEM;
1309 
1310         ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1311         ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1312         ftrace_mod->enable = enable;
1313 
1314         if (!ftrace_mod->func || !ftrace_mod->module)
1315                 goto out_free;
1316 
1317         list_add(&ftrace_mod->list, mod_head);
1318 
1319         return 0;
1320 
1321  out_free:
1322         free_ftrace_mod(ftrace_mod);
1323 
1324         return -ENOMEM;
1325 }
1326 
1327 static struct ftrace_hash *
1328 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1329 {
1330         struct ftrace_func_entry *entry;
1331         struct ftrace_hash *new_hash;
1332         int size;
1333         int ret;
1334         int i;
1335 
1336         new_hash = alloc_ftrace_hash(size_bits);
1337         if (!new_hash)
1338                 return NULL;
1339 
1340         if (hash)
1341                 new_hash->flags = hash->flags;
1342 
1343         /* Empty hash? */
1344         if (ftrace_hash_empty(hash))
1345                 return new_hash;
1346 
1347         size = 1 << hash->size_bits;
1348         for (i = 0; i < size; i++) {
1349                 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1350                         ret = add_hash_entry(new_hash, entry->ip);
1351                         if (ret < 0)
1352                                 goto free_hash;
1353                 }
1354         }
1355 
1356         FTRACE_WARN_ON(new_hash->count != hash->count);
1357 
1358         return new_hash;
1359 
1360  free_hash:
1361         free_ftrace_hash(new_hash);
1362         return NULL;
1363 }
1364 
1365 static void
1366 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1367 static void
1368 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1369 
1370 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1371                                        struct ftrace_hash *new_hash);
1372 
1373 static struct ftrace_hash *
1374 __ftrace_hash_move(struct ftrace_hash *src)
1375 {
1376         struct ftrace_func_entry *entry;
1377         struct hlist_node *tn;
1378         struct hlist_head *hhd;
1379         struct ftrace_hash *new_hash;
1380         int size = src->count;
1381         int bits = 0;
1382         int i;
1383 
1384         /*
1385          * If the new source is empty, just return the empty_hash.
1386          */
1387         if (ftrace_hash_empty(src))
1388                 return EMPTY_HASH;
1389 
1390         /*
1391          * Make the hash size about 1/2 the # found
1392          */
1393         for (size /= 2; size; size >>= 1)
1394                 bits++;
1395 
1396         /* Don't allocate too much */
1397         if (bits > FTRACE_HASH_MAX_BITS)
1398                 bits = FTRACE_HASH_MAX_BITS;
1399 
1400         new_hash = alloc_ftrace_hash(bits);
1401         if (!new_hash)
1402                 return NULL;
1403 
1404         new_hash->flags = src->flags;
1405 
1406         size = 1 << src->size_bits;
1407         for (i = 0; i < size; i++) {
1408                 hhd = &src->buckets[i];
1409                 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1410                         remove_hash_entry(src, entry);
1411                         __add_hash_entry(new_hash, entry);
1412                 }
1413         }
1414 
1415         return new_hash;
1416 }
1417 
1418 static int
1419 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1420                  struct ftrace_hash **dst, struct ftrace_hash *src)
1421 {
1422         struct ftrace_hash *new_hash;
1423         int ret;
1424 
1425         /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1426         if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1427                 return -EINVAL;
1428 
1429         new_hash = __ftrace_hash_move(src);
1430         if (!new_hash)
1431                 return -ENOMEM;
1432 
1433         /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1434         if (enable) {
1435                 /* IPMODIFY should be updated only when filter_hash updating */
1436                 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1437                 if (ret < 0) {
1438                         free_ftrace_hash(new_hash);
1439                         return ret;
1440                 }
1441         }
1442 
1443         /*
1444          * Remove the current set, update the hash and add
1445          * them back.
1446          */
1447         ftrace_hash_rec_disable_modify(ops, enable);
1448 
1449         rcu_assign_pointer(*dst, new_hash);
1450 
1451         ftrace_hash_rec_enable_modify(ops, enable);
1452 
1453         return 0;
1454 }
1455 
1456 static bool hash_contains_ip(unsigned long ip,
1457                              struct ftrace_ops_hash *hash)
1458 {
1459         /*
1460          * The function record is a match if it exists in the filter
1461          * hash and not in the notrace hash. Note, an emty hash is
1462          * considered a match for the filter hash, but an empty
1463          * notrace hash is considered not in the notrace hash.
1464          */
1465         return (ftrace_hash_empty(hash->filter_hash) ||
1466                 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1467                 (ftrace_hash_empty(hash->notrace_hash) ||
1468                  !__ftrace_lookup_ip(hash->notrace_hash, ip));
1469 }
1470 
1471 /*
1472  * Test the hashes for this ops to see if we want to call
1473  * the ops->func or not.
1474  *
1475  * It's a match if the ip is in the ops->filter_hash or
1476  * the filter_hash does not exist or is empty,
1477  *  AND
1478  * the ip is not in the ops->notrace_hash.
1479  *
1480  * This needs to be called with preemption disabled as
1481  * the hashes are freed with call_rcu().
1482  */
1483 int
1484 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1485 {
1486         struct ftrace_ops_hash hash;
1487         int ret;
1488 
1489 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1490         /*
1491          * There's a small race when adding ops that the ftrace handler
1492          * that wants regs, may be called without them. We can not
1493          * allow that handler to be called if regs is NULL.
1494          */
1495         if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1496                 return 0;
1497 #endif
1498 
1499         rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1500         rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1501 
1502         if (hash_contains_ip(ip, &hash))
1503                 ret = 1;
1504         else
1505                 ret = 0;
1506 
1507         return ret;
1508 }
1509 
1510 /*
1511  * This is a double for. Do not use 'break' to break out of the loop,
1512  * you must use a goto.
1513  */
1514 #define do_for_each_ftrace_rec(pg, rec)                                 \
1515         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
1516                 int _____i;                                             \
1517                 for (_____i = 0; _____i < pg->index; _____i++) {        \
1518                         rec = &pg->records[_____i];
1519 
1520 #define while_for_each_ftrace_rec()             \
1521                 }                               \
1522         }
1523 
1524 
1525 static int ftrace_cmp_recs(const void *a, const void *b)
1526 {
1527         const struct dyn_ftrace *key = a;
1528         const struct dyn_ftrace *rec = b;
1529 
1530         if (key->flags < rec->ip)
1531                 return -1;
1532         if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1533                 return 1;
1534         return 0;
1535 }
1536 
1537 /**
1538  * ftrace_location_range - return the first address of a traced location
1539  *      if it touches the given ip range
1540  * @start: start of range to search.
1541  * @end: end of range to search (inclusive). @end points to the last byte
1542  *      to check.
1543  *
1544  * Returns rec->ip if the related ftrace location is a least partly within
1545  * the given address range. That is, the first address of the instruction
1546  * that is either a NOP or call to the function tracer. It checks the ftrace
1547  * internal tables to determine if the address belongs or not.
1548  */
1549 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1550 {
1551         struct ftrace_page *pg;
1552         struct dyn_ftrace *rec;
1553         struct dyn_ftrace key;
1554 
1555         key.ip = start;
1556         key.flags = end;        /* overload flags, as it is unsigned long */
1557 
1558         for (pg = ftrace_pages_start; pg; pg = pg->next) {
1559                 if (end < pg->records[0].ip ||
1560                     start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1561                         continue;
1562                 rec = bsearch(&key, pg->records, pg->index,
1563                               sizeof(struct dyn_ftrace),
1564                               ftrace_cmp_recs);
1565                 if (rec)
1566                         return rec->ip;
1567         }
1568 
1569         return 0;
1570 }
1571 
1572 /**
1573  * ftrace_location - return true if the ip giving is a traced location
1574  * @ip: the instruction pointer to check
1575  *
1576  * Returns rec->ip if @ip given is a pointer to a ftrace location.
1577  * That is, the instruction that is either a NOP or call to
1578  * the function tracer. It checks the ftrace internal tables to
1579  * determine if the address belongs or not.
1580  */
1581 unsigned long ftrace_location(unsigned long ip)
1582 {
1583         return ftrace_location_range(ip, ip);
1584 }
1585 
1586 /**
1587  * ftrace_text_reserved - return true if range contains an ftrace location
1588  * @start: start of range to search
1589  * @end: end of range to search (inclusive). @end points to the last byte to check.
1590  *
1591  * Returns 1 if @start and @end contains a ftrace location.
1592  * That is, the instruction that is either a NOP or call to
1593  * the function tracer. It checks the ftrace internal tables to
1594  * determine if the address belongs or not.
1595  */
1596 int ftrace_text_reserved(const void *start, const void *end)
1597 {
1598         unsigned long ret;
1599 
1600         ret = ftrace_location_range((unsigned long)start,
1601                                     (unsigned long)end);
1602 
1603         return (int)!!ret;
1604 }
1605 
1606 /* Test if ops registered to this rec needs regs */
1607 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1608 {
1609         struct ftrace_ops *ops;
1610         bool keep_regs = false;
1611 
1612         for (ops = ftrace_ops_list;
1613              ops != &ftrace_list_end; ops = ops->next) {
1614                 /* pass rec in as regs to have non-NULL val */
1615                 if (ftrace_ops_test(ops, rec->ip, rec)) {
1616                         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1617                                 keep_regs = true;
1618                                 break;
1619                         }
1620                 }
1621         }
1622 
1623         return  keep_regs;
1624 }
1625 
1626 static struct ftrace_ops *
1627 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1628 static struct ftrace_ops *
1629 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1630 
1631 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1632                                      int filter_hash,
1633                                      bool inc)
1634 {
1635         struct ftrace_hash *hash;
1636         struct ftrace_hash *other_hash;
1637         struct ftrace_page *pg;
1638         struct dyn_ftrace *rec;
1639         bool update = false;
1640         int count = 0;
1641         int all = false;
1642 
1643         /* Only update if the ops has been registered */
1644         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1645                 return false;
1646 
1647         /*
1648          * In the filter_hash case:
1649          *   If the count is zero, we update all records.
1650          *   Otherwise we just update the items in the hash.
1651          *
1652          * In the notrace_hash case:
1653          *   We enable the update in the hash.
1654          *   As disabling notrace means enabling the tracing,
1655          *   and enabling notrace means disabling, the inc variable
1656          *   gets inversed.
1657          */
1658         if (filter_hash) {
1659                 hash = ops->func_hash->filter_hash;
1660                 other_hash = ops->func_hash->notrace_hash;
1661                 if (ftrace_hash_empty(hash))
1662                         all = true;
1663         } else {
1664                 inc = !inc;
1665                 hash = ops->func_hash->notrace_hash;
1666                 other_hash = ops->func_hash->filter_hash;
1667                 /*
1668                  * If the notrace hash has no items,
1669                  * then there's nothing to do.
1670                  */
1671                 if (ftrace_hash_empty(hash))
1672                         return false;
1673         }
1674 
1675         do_for_each_ftrace_rec(pg, rec) {
1676                 int in_other_hash = 0;
1677                 int in_hash = 0;
1678                 int match = 0;
1679 
1680                 if (rec->flags & FTRACE_FL_DISABLED)
1681                         continue;
1682 
1683                 if (all) {
1684                         /*
1685                          * Only the filter_hash affects all records.
1686                          * Update if the record is not in the notrace hash.
1687                          */
1688                         if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1689                                 match = 1;
1690                 } else {
1691                         in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1692                         in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1693 
1694                         /*
1695                          * If filter_hash is set, we want to match all functions
1696                          * that are in the hash but not in the other hash.
1697                          *
1698                          * If filter_hash is not set, then we are decrementing.
1699                          * That means we match anything that is in the hash
1700                          * and also in the other_hash. That is, we need to turn
1701                          * off functions in the other hash because they are disabled
1702                          * by this hash.
1703                          */
1704                         if (filter_hash && in_hash && !in_other_hash)
1705                                 match = 1;
1706                         else if (!filter_hash && in_hash &&
1707                                  (in_other_hash || ftrace_hash_empty(other_hash)))
1708                                 match = 1;
1709                 }
1710                 if (!match)
1711                         continue;
1712 
1713                 if (inc) {
1714                         rec->flags++;
1715                         if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1716                                 return false;
1717 
1718                         /*
1719                          * If there's only a single callback registered to a
1720                          * function, and the ops has a trampoline registered
1721                          * for it, then we can call it directly.
1722                          */
1723                         if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1724                                 rec->flags |= FTRACE_FL_TRAMP;
1725                         else
1726                                 /*
1727                                  * If we are adding another function callback
1728                                  * to this function, and the previous had a
1729                                  * custom trampoline in use, then we need to go
1730                                  * back to the default trampoline.
1731                                  */
1732                                 rec->flags &= ~FTRACE_FL_TRAMP;
1733 
1734                         /*
1735                          * If any ops wants regs saved for this function
1736                          * then all ops will get saved regs.
1737                          */
1738                         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1739                                 rec->flags |= FTRACE_FL_REGS;
1740                 } else {
1741                         if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1742                                 return false;
1743                         rec->flags--;
1744 
1745                         /*
1746                          * If the rec had REGS enabled and the ops that is
1747                          * being removed had REGS set, then see if there is
1748                          * still any ops for this record that wants regs.
1749                          * If not, we can stop recording them.
1750                          */
1751                         if (ftrace_rec_count(rec) > 0 &&
1752                             rec->flags & FTRACE_FL_REGS &&
1753                             ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1754                                 if (!test_rec_ops_needs_regs(rec))
1755                                         rec->flags &= ~FTRACE_FL_REGS;
1756                         }
1757 
1758                         /*
1759                          * The TRAMP needs to be set only if rec count
1760                          * is decremented to one, and the ops that is
1761                          * left has a trampoline. As TRAMP can only be
1762                          * enabled if there is only a single ops attached
1763                          * to it.
1764                          */
1765                         if (ftrace_rec_count(rec) == 1 &&
1766                             ftrace_find_tramp_ops_any(rec))
1767                                 rec->flags |= FTRACE_FL_TRAMP;
1768                         else
1769                                 rec->flags &= ~FTRACE_FL_TRAMP;
1770 
1771                         /*
1772                          * flags will be cleared in ftrace_check_record()
1773                          * if rec count is zero.
1774                          */
1775                 }
1776                 count++;
1777 
1778                 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1779                 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1780 
1781                 /* Shortcut, if we handled all records, we are done. */
1782                 if (!all && count == hash->count)
1783                         return update;
1784         } while_for_each_ftrace_rec();
1785 
1786         return update;
1787 }
1788 
1789 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1790                                     int filter_hash)
1791 {
1792         return __ftrace_hash_rec_update(ops, filter_hash, 0);
1793 }
1794 
1795 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1796                                    int filter_hash)
1797 {
1798         return __ftrace_hash_rec_update(ops, filter_hash, 1);
1799 }
1800 
1801 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1802                                           int filter_hash, int inc)
1803 {
1804         struct ftrace_ops *op;
1805 
1806         __ftrace_hash_rec_update(ops, filter_hash, inc);
1807 
1808         if (ops->func_hash != &global_ops.local_hash)
1809                 return;
1810 
1811         /*
1812          * If the ops shares the global_ops hash, then we need to update
1813          * all ops that are enabled and use this hash.
1814          */
1815         do_for_each_ftrace_op(op, ftrace_ops_list) {
1816                 /* Already done */
1817                 if (op == ops)
1818                         continue;
1819                 if (op->func_hash == &global_ops.local_hash)
1820                         __ftrace_hash_rec_update(op, filter_hash, inc);
1821         } while_for_each_ftrace_op(op);
1822 }
1823 
1824 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1825                                            int filter_hash)
1826 {
1827         ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1828 }
1829 
1830 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1831                                           int filter_hash)
1832 {
1833         ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1834 }
1835 
1836 /*
1837  * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1838  * or no-needed to update, -EBUSY if it detects a conflict of the flag
1839  * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1840  * Note that old_hash and new_hash has below meanings
1841  *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1842  *  - If the hash is EMPTY_HASH, it hits nothing
1843  *  - Anything else hits the recs which match the hash entries.
1844  */
1845 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1846                                          struct ftrace_hash *old_hash,
1847                                          struct ftrace_hash *new_hash)
1848 {
1849         struct ftrace_page *pg;
1850         struct dyn_ftrace *rec, *end = NULL;
1851         int in_old, in_new;
1852 
1853         /* Only update if the ops has been registered */
1854         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1855                 return 0;
1856 
1857         if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1858                 return 0;
1859 
1860         /*
1861          * Since the IPMODIFY is a very address sensitive action, we do not
1862          * allow ftrace_ops to set all functions to new hash.
1863          */
1864         if (!new_hash || !old_hash)
1865                 return -EINVAL;
1866 
1867         /* Update rec->flags */
1868         do_for_each_ftrace_rec(pg, rec) {
1869 
1870                 if (rec->flags & FTRACE_FL_DISABLED)
1871                         continue;
1872 
1873                 /* We need to update only differences of filter_hash */
1874                 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1875                 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1876                 if (in_old == in_new)
1877                         continue;
1878 
1879                 if (in_new) {
1880                         /* New entries must ensure no others are using it */
1881                         if (rec->flags & FTRACE_FL_IPMODIFY)
1882                                 goto rollback;
1883                         rec->flags |= FTRACE_FL_IPMODIFY;
1884                 } else /* Removed entry */
1885                         rec->flags &= ~FTRACE_FL_IPMODIFY;
1886         } while_for_each_ftrace_rec();
1887 
1888         return 0;
1889 
1890 rollback:
1891         end = rec;
1892 
1893         /* Roll back what we did above */
1894         do_for_each_ftrace_rec(pg, rec) {
1895 
1896                 if (rec->flags & FTRACE_FL_DISABLED)
1897                         continue;
1898 
1899                 if (rec == end)
1900                         goto err_out;
1901 
1902                 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1903                 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1904                 if (in_old == in_new)
1905                         continue;
1906 
1907                 if (in_new)
1908                         rec->flags &= ~FTRACE_FL_IPMODIFY;
1909                 else
1910                         rec->flags |= FTRACE_FL_IPMODIFY;
1911         } while_for_each_ftrace_rec();
1912 
1913 err_out:
1914         return -EBUSY;
1915 }
1916 
1917 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1918 {
1919         struct ftrace_hash *hash = ops->func_hash->filter_hash;
1920 
1921         if (ftrace_hash_empty(hash))
1922                 hash = NULL;
1923 
1924         return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1925 }
1926 
1927 /* Disabling always succeeds */
1928 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1929 {
1930         struct ftrace_hash *hash = ops->func_hash->filter_hash;
1931 
1932         if (ftrace_hash_empty(hash))
1933                 hash = NULL;
1934 
1935         __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1936 }
1937 
1938 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1939                                        struct ftrace_hash *new_hash)
1940 {
1941         struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1942 
1943         if (ftrace_hash_empty(old_hash))
1944                 old_hash = NULL;
1945 
1946         if (ftrace_hash_empty(new_hash))
1947                 new_hash = NULL;
1948 
1949         return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1950 }
1951 
1952 static void print_ip_ins(const char *fmt, const unsigned char *p)
1953 {
1954         int i;
1955 
1956         printk(KERN_CONT "%s", fmt);
1957 
1958         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1959                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1960 }
1961 
1962 enum ftrace_bug_type ftrace_bug_type;
1963 const void *ftrace_expected;
1964 
1965 static void print_bug_type(void)
1966 {
1967         switch (ftrace_bug_type) {
1968         case FTRACE_BUG_UNKNOWN:
1969                 break;
1970         case FTRACE_BUG_INIT:
1971                 pr_info("Initializing ftrace call sites\n");
1972                 break;
1973         case FTRACE_BUG_NOP:
1974                 pr_info("Setting ftrace call site to NOP\n");
1975                 break;
1976         case FTRACE_BUG_CALL:
1977                 pr_info("Setting ftrace call site to call ftrace function\n");
1978                 break;
1979         case FTRACE_BUG_UPDATE:
1980                 pr_info("Updating ftrace call site to call a different ftrace function\n");
1981                 break;
1982         }
1983 }
1984 
1985 /**
1986  * ftrace_bug - report and shutdown function tracer
1987  * @failed: The failed type (EFAULT, EINVAL, EPERM)
1988  * @rec: The record that failed
1989  *
1990  * The arch code that enables or disables the function tracing
1991  * can call ftrace_bug() when it has detected a problem in
1992  * modifying the code. @failed should be one of either:
1993  * EFAULT - if the problem happens on reading the @ip address
1994  * EINVAL - if what is read at @ip is not what was expected
1995  * EPERM - if the problem happens on writing to the @ip address
1996  */
1997 void ftrace_bug(int failed, struct dyn_ftrace *rec)
1998 {
1999         unsigned long ip = rec ? rec->ip : 0;
2000 
2001         switch (failed) {
2002         case -EFAULT:
2003                 FTRACE_WARN_ON_ONCE(1);
2004                 pr_info("ftrace faulted on modifying ");
2005                 print_ip_sym(ip);
2006                 break;
2007         case -EINVAL:
2008                 FTRACE_WARN_ON_ONCE(1);
2009                 pr_info("ftrace failed to modify ");
2010                 print_ip_sym(ip);
2011                 print_ip_ins(" actual:   ", (unsigned char *)ip);
2012                 pr_cont("\n");
2013                 if (ftrace_expected) {
2014                         print_ip_ins(" expected: ", ftrace_expected);
2015                         pr_cont("\n");
2016                 }
2017                 break;
2018         case -EPERM:
2019                 FTRACE_WARN_ON_ONCE(1);
2020                 pr_info("ftrace faulted on writing ");
2021                 print_ip_sym(ip);
2022                 break;
2023         default:
2024                 FTRACE_WARN_ON_ONCE(1);
2025                 pr_info("ftrace faulted on unknown error ");
2026                 print_ip_sym(ip);
2027         }
2028         print_bug_type();
2029         if (rec) {
2030                 struct ftrace_ops *ops = NULL;
2031 
2032                 pr_info("ftrace record flags: %lx\n", rec->flags);
2033                 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2034                         rec->flags & FTRACE_FL_REGS ? " R" : "  ");
2035                 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2036                         ops = ftrace_find_tramp_ops_any(rec);
2037                         if (ops) {
2038                                 do {
2039                                         pr_cont("\ttramp: %pS (%pS)",
2040                                                 (void *)ops->trampoline,
2041                                                 (void *)ops->func);
2042                                         ops = ftrace_find_tramp_ops_next(rec, ops);
2043                                 } while (ops);
2044                         } else
2045                                 pr_cont("\ttramp: ERROR!");
2046 
2047                 }
2048                 ip = ftrace_get_addr_curr(rec);
2049                 pr_cont("\n expected tramp: %lx\n", ip);
2050         }
2051 }
2052 
2053 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2054 {
2055         unsigned long flag = 0UL;
2056 
2057         ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2058 
2059         if (rec->flags & FTRACE_FL_DISABLED)
2060                 return FTRACE_UPDATE_IGNORE;
2061 
2062         /*
2063          * If we are updating calls:
2064          *
2065          *   If the record has a ref count, then we need to enable it
2066          *   because someone is using it.
2067          *
2068          *   Otherwise we make sure its disabled.
2069          *
2070          * If we are disabling calls, then disable all records that
2071          * are enabled.
2072          */
2073         if (enable && ftrace_rec_count(rec))
2074                 flag = FTRACE_FL_ENABLED;
2075 
2076         /*
2077          * If enabling and the REGS flag does not match the REGS_EN, or
2078          * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2079          * this record. Set flags to fail the compare against ENABLED.
2080          */
2081         if (flag) {
2082                 if (!(rec->flags & FTRACE_FL_REGS) != 
2083                     !(rec->flags & FTRACE_FL_REGS_EN))
2084                         flag |= FTRACE_FL_REGS;
2085 
2086                 if (!(rec->flags & FTRACE_FL_TRAMP) != 
2087                     !(rec->flags & FTRACE_FL_TRAMP_EN))
2088                         flag |= FTRACE_FL_TRAMP;
2089         }
2090 
2091         /* If the state of this record hasn't changed, then do nothing */
2092         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2093                 return FTRACE_UPDATE_IGNORE;
2094 
2095         if (flag) {
2096                 /* Save off if rec is being enabled (for return value) */
2097                 flag ^= rec->flags & FTRACE_FL_ENABLED;
2098 
2099                 if (update) {
2100                         rec->flags |= FTRACE_FL_ENABLED;
2101                         if (flag & FTRACE_FL_REGS) {
2102                                 if (rec->flags & FTRACE_FL_REGS)
2103                                         rec->flags |= FTRACE_FL_REGS_EN;
2104                                 else
2105                                         rec->flags &= ~FTRACE_FL_REGS_EN;
2106                         }
2107                         if (flag & FTRACE_FL_TRAMP) {
2108                                 if (rec->flags & FTRACE_FL_TRAMP)
2109                                         rec->flags |= FTRACE_FL_TRAMP_EN;
2110                                 else
2111                                         rec->flags &= ~FTRACE_FL_TRAMP_EN;
2112                         }
2113                 }
2114 
2115                 /*
2116                  * If this record is being updated from a nop, then
2117                  *   return UPDATE_MAKE_CALL.
2118                  * Otherwise,
2119                  *   return UPDATE_MODIFY_CALL to tell the caller to convert
2120                  *   from the save regs, to a non-save regs function or
2121                  *   vice versa, or from a trampoline call.
2122                  */
2123                 if (flag & FTRACE_FL_ENABLED) {
2124                         ftrace_bug_type = FTRACE_BUG_CALL;
2125                         return FTRACE_UPDATE_MAKE_CALL;
2126                 }
2127 
2128                 ftrace_bug_type = FTRACE_BUG_UPDATE;
2129                 return FTRACE_UPDATE_MODIFY_CALL;
2130         }
2131 
2132         if (update) {
2133                 /* If there's no more users, clear all flags */
2134                 if (!ftrace_rec_count(rec))
2135                         rec->flags = 0;
2136                 else
2137                         /*
2138                          * Just disable the record, but keep the ops TRAMP
2139                          * and REGS states. The _EN flags must be disabled though.
2140                          */
2141                         rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2142                                         FTRACE_FL_REGS_EN);
2143         }
2144 
2145         ftrace_bug_type = FTRACE_BUG_NOP;
2146         return FTRACE_UPDATE_MAKE_NOP;
2147 }
2148 
2149 /**
2150  * ftrace_update_record, set a record that now is tracing or not
2151  * @rec: the record to update
2152  * @enable: set to true if the record is tracing, false to force disable
2153  *
2154  * The records that represent all functions that can be traced need
2155  * to be updated when tracing has been enabled.
2156  */
2157 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2158 {
2159         return ftrace_check_record(rec, enable, true);
2160 }
2161 
2162 /**
2163  * ftrace_test_record, check if the record has been enabled or not
2164  * @rec: the record to test
2165  * @enable: set to true to check if enabled, false if it is disabled
2166  *
2167  * The arch code may need to test if a record is already set to
2168  * tracing to determine how to modify the function code that it
2169  * represents.
2170  */
2171 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2172 {
2173         return ftrace_check_record(rec, enable, false);
2174 }
2175 
2176 static struct ftrace_ops *
2177 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2178 {
2179         struct ftrace_ops *op;
2180         unsigned long ip = rec->ip;
2181 
2182         do_for_each_ftrace_op(op, ftrace_ops_list) {
2183 
2184                 if (!op->trampoline)
2185                         continue;
2186 
2187                 if (hash_contains_ip(ip, op->func_hash))
2188                         return op;
2189         } while_for_each_ftrace_op(op);
2190 
2191         return NULL;
2192 }
2193 
2194 static struct ftrace_ops *
2195 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2196                            struct ftrace_ops *op)
2197 {
2198         unsigned long ip = rec->ip;
2199 
2200         while_for_each_ftrace_op(op) {
2201 
2202                 if (!op->trampoline)
2203                         continue;
2204 
2205                 if (hash_contains_ip(ip, op->func_hash))
2206                         return op;
2207         } 
2208 
2209         return NULL;
2210 }
2211 
2212 static struct ftrace_ops *
2213 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2214 {
2215         struct ftrace_ops *op;
2216         unsigned long ip = rec->ip;
2217 
2218         /*
2219          * Need to check removed ops first.
2220          * If they are being removed, and this rec has a tramp,
2221          * and this rec is in the ops list, then it would be the
2222          * one with the tramp.
2223          */
2224         if (removed_ops) {
2225                 if (hash_contains_ip(ip, &removed_ops->old_hash))
2226                         return removed_ops;
2227         }
2228 
2229         /*
2230          * Need to find the current trampoline for a rec.
2231          * Now, a trampoline is only attached to a rec if there
2232          * was a single 'ops' attached to it. But this can be called
2233          * when we are adding another op to the rec or removing the
2234          * current one. Thus, if the op is being added, we can
2235          * ignore it because it hasn't attached itself to the rec
2236          * yet.
2237          *
2238          * If an ops is being modified (hooking to different functions)
2239          * then we don't care about the new functions that are being
2240          * added, just the old ones (that are probably being removed).
2241          *
2242          * If we are adding an ops to a function that already is using
2243          * a trampoline, it needs to be removed (trampolines are only
2244          * for single ops connected), then an ops that is not being
2245          * modified also needs to be checked.
2246          */
2247         do_for_each_ftrace_op(op, ftrace_ops_list) {
2248 
2249                 if (!op->trampoline)
2250                         continue;
2251 
2252                 /*
2253                  * If the ops is being added, it hasn't gotten to
2254                  * the point to be removed from this tree yet.
2255                  */
2256                 if (op->flags & FTRACE_OPS_FL_ADDING)
2257                         continue;
2258 
2259 
2260                 /*
2261                  * If the ops is being modified and is in the old
2262                  * hash, then it is probably being removed from this
2263                  * function.
2264                  */
2265                 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2266                     hash_contains_ip(ip, &op->old_hash))
2267                         return op;
2268                 /*
2269                  * If the ops is not being added or modified, and it's
2270                  * in its normal filter hash, then this must be the one
2271                  * we want!
2272                  */
2273                 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2274                     hash_contains_ip(ip, op->func_hash))
2275                         return op;
2276 
2277         } while_for_each_ftrace_op(op);
2278 
2279         return NULL;
2280 }
2281 
2282 static struct ftrace_ops *
2283 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2284 {
2285         struct ftrace_ops *op;
2286         unsigned long ip = rec->ip;
2287 
2288         do_for_each_ftrace_op(op, ftrace_ops_list) {
2289                 /* pass rec in as regs to have non-NULL val */
2290                 if (hash_contains_ip(ip, op->func_hash))
2291                         return op;
2292         } while_for_each_ftrace_op(op);
2293 
2294         return NULL;
2295 }
2296 
2297 /**
2298  * ftrace_get_addr_new - Get the call address to set to
2299  * @rec:  The ftrace record descriptor
2300  *
2301  * If the record has the FTRACE_FL_REGS set, that means that it
2302  * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2303  * is not not set, then it wants to convert to the normal callback.
2304  *
2305  * Returns the address of the trampoline to set to
2306  */
2307 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2308 {
2309         struct ftrace_ops *ops;
2310 
2311         /* Trampolines take precedence over regs */
2312         if (rec->flags & FTRACE_FL_TRAMP) {
2313                 ops = ftrace_find_tramp_ops_new(rec);
2314                 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2315                         pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2316                                 (void *)rec->ip, (void *)rec->ip, rec->flags);
2317                         /* Ftrace is shutting down, return anything */
2318                         return (unsigned long)FTRACE_ADDR;
2319                 }
2320                 return ops->trampoline;
2321         }
2322 
2323         if (rec->flags & FTRACE_FL_REGS)
2324                 return (unsigned long)FTRACE_REGS_ADDR;
2325         else
2326                 return (unsigned long)FTRACE_ADDR;
2327 }
2328 
2329 /**
2330  * ftrace_get_addr_curr - Get the call address that is already there
2331  * @rec:  The ftrace record descriptor
2332  *
2333  * The FTRACE_FL_REGS_EN is set when the record already points to
2334  * a function that saves all the regs. Basically the '_EN' version
2335  * represents the current state of the function.
2336  *
2337  * Returns the address of the trampoline that is currently being called
2338  */
2339 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2340 {
2341         struct ftrace_ops *ops;
2342 
2343         /* Trampolines take precedence over regs */
2344         if (rec->flags & FTRACE_FL_TRAMP_EN) {
2345                 ops = ftrace_find_tramp_ops_curr(rec);
2346                 if (FTRACE_WARN_ON(!ops)) {
2347                         pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2348                                 (void *)rec->ip, (void *)rec->ip);
2349                         /* Ftrace is shutting down, return anything */
2350                         return (unsigned long)FTRACE_ADDR;
2351                 }
2352                 return ops->trampoline;
2353         }
2354 
2355         if (rec->flags & FTRACE_FL_REGS_EN)
2356                 return (unsigned long)FTRACE_REGS_ADDR;
2357         else
2358                 return (unsigned long)FTRACE_ADDR;
2359 }
2360 
2361 static int
2362 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2363 {
2364         unsigned long ftrace_old_addr;
2365         unsigned long ftrace_addr;
2366         int ret;
2367 
2368         ftrace_addr = ftrace_get_addr_new(rec);
2369 
2370         /* This needs to be done before we call ftrace_update_record */
2371         ftrace_old_addr = ftrace_get_addr_curr(rec);
2372 
2373         ret = ftrace_update_record(rec, enable);
2374 
2375         ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2376 
2377         switch (ret) {
2378         case FTRACE_UPDATE_IGNORE:
2379                 return 0;
2380 
2381         case FTRACE_UPDATE_MAKE_CALL:
2382                 ftrace_bug_type = FTRACE_BUG_CALL;
2383                 return ftrace_make_call(rec, ftrace_addr);
2384 
2385         case FTRACE_UPDATE_MAKE_NOP:
2386                 ftrace_bug_type = FTRACE_BUG_NOP;
2387                 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2388 
2389         case FTRACE_UPDATE_MODIFY_CALL:
2390                 ftrace_bug_type = FTRACE_BUG_UPDATE;
2391                 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2392         }
2393 
2394         return -1; /* unknown ftrace bug */
2395 }
2396 
2397 void __weak ftrace_replace_code(int mod_flags)
2398 {
2399         struct dyn_ftrace *rec;
2400         struct ftrace_page *pg;
2401         bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2402         int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2403         int failed;
2404 
2405         if (unlikely(ftrace_disabled))
2406                 return;
2407 
2408         do_for_each_ftrace_rec(pg, rec) {
2409 
2410                 if (rec->flags & FTRACE_FL_DISABLED)
2411                         continue;
2412 
2413                 failed = __ftrace_replace_code(rec, enable);
2414                 if (failed) {
2415                         ftrace_bug(failed, rec);
2416                         /* Stop processing */
2417                         return;
2418                 }
2419                 if (schedulable)
2420                         cond_resched();
2421         } while_for_each_ftrace_rec();
2422 }
2423 
2424 struct ftrace_rec_iter {
2425         struct ftrace_page      *pg;
2426         int                     index;
2427 };
2428 
2429 /**
2430  * ftrace_rec_iter_start, start up iterating over traced functions
2431  *
2432  * Returns an iterator handle that is used to iterate over all
2433  * the records that represent address locations where functions
2434  * are traced.
2435  *
2436  * May return NULL if no records are available.
2437  */
2438 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2439 {
2440         /*
2441          * We only use a single iterator.
2442          * Protected by the ftrace_lock mutex.
2443          */
2444         static struct ftrace_rec_iter ftrace_rec_iter;
2445         struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2446 
2447         iter->pg = ftrace_pages_start;
2448         iter->index = 0;
2449 
2450         /* Could have empty pages */
2451         while (iter->pg && !iter->pg->index)
2452                 iter->pg = iter->pg->next;
2453 
2454         if (!iter->pg)
2455                 return NULL;
2456 
2457         return iter;
2458 }
2459 
2460 /**
2461  * ftrace_rec_iter_next, get the next record to process.
2462  * @iter: The handle to the iterator.
2463  *
2464  * Returns the next iterator after the given iterator @iter.
2465  */
2466 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2467 {
2468         iter->index++;
2469 
2470         if (iter->index >= iter->pg->index) {
2471                 iter->pg = iter->pg->next;
2472                 iter->index = 0;
2473 
2474                 /* Could have empty pages */
2475                 while (iter->pg && !iter->pg->index)
2476                         iter->pg = iter->pg->next;
2477         }
2478 
2479         if (!iter->pg)
2480                 return NULL;
2481 
2482         return iter;
2483 }
2484 
2485 /**
2486  * ftrace_rec_iter_record, get the record at the iterator location
2487  * @iter: The current iterator location
2488  *
2489  * Returns the record that the current @iter is at.
2490  */
2491 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2492 {
2493         return &iter->pg->records[iter->index];
2494 }
2495 
2496 static int
2497 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2498 {
2499         int ret;
2500 
2501         if (unlikely(ftrace_disabled))
2502                 return 0;
2503 
2504         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2505         if (ret) {
2506                 ftrace_bug_type = FTRACE_BUG_INIT;
2507                 ftrace_bug(ret, rec);
2508                 return 0;
2509         }
2510         return 1;
2511 }
2512 
2513 /*
2514  * archs can override this function if they must do something
2515  * before the modifying code is performed.
2516  */
2517 int __weak ftrace_arch_code_modify_prepare(void)
2518 {
2519         return 0;
2520 }
2521 
2522 /*
2523  * archs can override this function if they must do something
2524  * after the modifying code is performed.
2525  */
2526 int __weak ftrace_arch_code_modify_post_process(void)
2527 {
2528         return 0;
2529 }
2530 
2531 void ftrace_modify_all_code(int command)
2532 {
2533         int update = command & FTRACE_UPDATE_TRACE_FUNC;
2534         int mod_flags = 0;
2535         int err = 0;
2536 
2537         if (command & FTRACE_MAY_SLEEP)
2538                 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2539 
2540         /*
2541          * If the ftrace_caller calls a ftrace_ops func directly,
2542          * we need to make sure that it only traces functions it
2543          * expects to trace. When doing the switch of functions,
2544          * we need to update to the ftrace_ops_list_func first
2545          * before the transition between old and new calls are set,
2546          * as the ftrace_ops_list_func will check the ops hashes
2547          * to make sure the ops are having the right functions
2548          * traced.
2549          */
2550         if (update) {
2551                 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2552                 if (FTRACE_WARN_ON(err))
2553                         return;
2554         }
2555 
2556         if (command & FTRACE_UPDATE_CALLS)
2557                 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2558         else if (command & FTRACE_DISABLE_CALLS)
2559                 ftrace_replace_code(mod_flags);
2560 
2561         if (update && ftrace_trace_function != ftrace_ops_list_func) {
2562                 function_trace_op = set_function_trace_op;
2563                 smp_wmb();
2564                 /* If irqs are disabled, we are in stop machine */
2565                 if (!irqs_disabled())
2566                         smp_call_function(ftrace_sync_ipi, NULL, 1);
2567                 err = ftrace_update_ftrace_func(ftrace_trace_function);
2568                 if (FTRACE_WARN_ON(err))
2569                         return;
2570         }
2571 
2572         if (command & FTRACE_START_FUNC_RET)
2573                 err = ftrace_enable_ftrace_graph_caller();
2574         else if (command & FTRACE_STOP_FUNC_RET)
2575                 err = ftrace_disable_ftrace_graph_caller();
2576         FTRACE_WARN_ON(err);
2577 }
2578 
2579 static int __ftrace_modify_code(void *data)
2580 {
2581         int *command = data;
2582 
2583         ftrace_modify_all_code(*command);
2584 
2585         return 0;
2586 }
2587 
2588 /**
2589  * ftrace_run_stop_machine, go back to the stop machine method
2590  * @command: The command to tell ftrace what to do
2591  *
2592  * If an arch needs to fall back to the stop machine method, the
2593  * it can call this function.
2594  */
2595 void ftrace_run_stop_machine(int command)
2596 {
2597         stop_machine(__ftrace_modify_code, &command, NULL);
2598 }
2599 
2600 /**
2601  * arch_ftrace_update_code, modify the code to trace or not trace
2602  * @command: The command that needs to be done
2603  *
2604  * Archs can override this function if it does not need to
2605  * run stop_machine() to modify code.
2606  */
2607 void __weak arch_ftrace_update_code(int command)
2608 {
2609         ftrace_run_stop_machine(command);
2610 }
2611 
2612 static void ftrace_run_update_code(int command)
2613 {
2614         int ret;
2615 
2616         ret = ftrace_arch_code_modify_prepare();
2617         FTRACE_WARN_ON(ret);
2618         if (ret)
2619                 return;
2620 
2621         /*
2622          * By default we use stop_machine() to modify the code.
2623          * But archs can do what ever they want as long as it
2624          * is safe. The stop_machine() is the safest, but also
2625          * produces the most overhead.
2626          */
2627         arch_ftrace_update_code(command);
2628 
2629         ret = ftrace_arch_code_modify_post_process();
2630         FTRACE_WARN_ON(ret);
2631 }
2632 
2633 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2634                                    struct ftrace_ops_hash *old_hash)
2635 {
2636         ops->flags |= FTRACE_OPS_FL_MODIFYING;
2637         ops->old_hash.filter_hash = old_hash->filter_hash;
2638         ops->old_hash.notrace_hash = old_hash->notrace_hash;
2639         ftrace_run_update_code(command);
2640         ops->old_hash.filter_hash = NULL;
2641         ops->old_hash.notrace_hash = NULL;
2642         ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2643 }
2644 
2645 static ftrace_func_t saved_ftrace_func;
2646 static int ftrace_start_up;
2647 
2648 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2649 {
2650 }
2651 
2652 static void ftrace_startup_enable(int command)
2653 {
2654         if (saved_ftrace_func != ftrace_trace_function) {
2655                 saved_ftrace_func = ftrace_trace_function;
2656                 command |= FTRACE_UPDATE_TRACE_FUNC;
2657         }
2658 
2659         if (!command || !ftrace_enabled)
2660                 return;
2661 
2662         ftrace_run_update_code(command);
2663 }
2664 
2665 static void ftrace_startup_all(int command)
2666 {
2667         update_all_ops = true;
2668         ftrace_startup_enable(command);
2669         update_all_ops = false;
2670 }
2671 
2672 int ftrace_startup(struct ftrace_ops *ops, int command)
2673 {
2674         int ret;
2675 
2676         if (unlikely(ftrace_disabled))
2677                 return -ENODEV;
2678 
2679         ret = __register_ftrace_function(ops);
2680         if (ret)
2681                 return ret;
2682 
2683         ftrace_start_up++;
2684 
2685         /*
2686          * Note that ftrace probes uses this to start up
2687          * and modify functions it will probe. But we still
2688          * set the ADDING flag for modification, as probes
2689          * do not have trampolines. If they add them in the
2690          * future, then the probes will need to distinguish
2691          * between adding and updating probes.
2692          */
2693         ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2694 
2695         ret = ftrace_hash_ipmodify_enable(ops);
2696         if (ret < 0) {
2697                 /* Rollback registration process */
2698                 __unregister_ftrace_function(ops);
2699                 ftrace_start_up--;
2700                 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2701                 return ret;
2702         }
2703 
2704         if (ftrace_hash_rec_enable(ops, 1))
2705                 command |= FTRACE_UPDATE_CALLS;
2706 
2707         ftrace_startup_enable(command);
2708 
2709         ops->flags &= ~FTRACE_OPS_FL_ADDING;
2710 
2711         return 0;
2712 }
2713 
2714 int ftrace_shutdown(struct ftrace_ops *ops, int command)
2715 {
2716         int ret;
2717 
2718         if (unlikely(ftrace_disabled))
2719                 return -ENODEV;
2720 
2721         ret = __unregister_ftrace_function(ops);
2722         if (ret)
2723                 return ret;
2724 
2725         ftrace_start_up--;
2726         /*
2727          * Just warn in case of unbalance, no need to kill ftrace, it's not
2728          * critical but the ftrace_call callers may be never nopped again after
2729          * further ftrace uses.
2730          */
2731         WARN_ON_ONCE(ftrace_start_up < 0);
2732 
2733         /* Disabling ipmodify never fails */
2734         ftrace_hash_ipmodify_disable(ops);
2735 
2736         if (ftrace_hash_rec_disable(ops, 1))
2737                 command |= FTRACE_UPDATE_CALLS;
2738 
2739         ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2740 
2741         if (saved_ftrace_func != ftrace_trace_function) {
2742                 saved_ftrace_func = ftrace_trace_function;
2743                 command |= FTRACE_UPDATE_TRACE_FUNC;
2744         }
2745 
2746         if (!command || !ftrace_enabled) {
2747                 /*
2748                  * If these are dynamic or per_cpu ops, they still
2749                  * need their data freed. Since, function tracing is
2750                  * not currently active, we can just free them
2751                  * without synchronizing all CPUs.
2752                  */
2753                 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2754                         goto free_ops;
2755 
2756                 return 0;
2757         }
2758 
2759         /*
2760          * If the ops uses a trampoline, then it needs to be
2761          * tested first on update.
2762          */
2763         ops->flags |= FTRACE_OPS_FL_REMOVING;
2764         removed_ops = ops;
2765 
2766         /* The trampoline logic checks the old hashes */
2767         ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2768         ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2769 
2770         ftrace_run_update_code(command);
2771 
2772         /*
2773          * If there's no more ops registered with ftrace, run a
2774          * sanity check to make sure all rec flags are cleared.
2775          */
2776         if (rcu_dereference_protected(ftrace_ops_list,
2777                         lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2778                 struct ftrace_page *pg;
2779                 struct dyn_ftrace *rec;
2780 
2781                 do_for_each_ftrace_rec(pg, rec) {
2782                         if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2783                                 pr_warn("  %pS flags:%lx\n",
2784                                         (void *)rec->ip, rec->flags);
2785                 } while_for_each_ftrace_rec();
2786         }
2787 
2788         ops->old_hash.filter_hash = NULL;
2789         ops->old_hash.notrace_hash = NULL;
2790 
2791         removed_ops = NULL;
2792         ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2793 
2794         /*
2795          * Dynamic ops may be freed, we must make sure that all
2796          * callers are done before leaving this function.
2797          * The same goes for freeing the per_cpu data of the per_cpu
2798          * ops.
2799          */
2800         if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2801                 /*
2802                  * We need to do a hard force of sched synchronization.
2803                  * This is because we use preempt_disable() to do RCU, but
2804                  * the function tracers can be called where RCU is not watching
2805                  * (like before user_exit()). We can not rely on the RCU
2806                  * infrastructure to do the synchronization, thus we must do it
2807                  * ourselves.
2808                  */
2809                 schedule_on_each_cpu(ftrace_sync);
2810 
2811                 /*
2812                  * When the kernel is preeptive, tasks can be preempted
2813                  * while on a ftrace trampoline. Just scheduling a task on
2814                  * a CPU is not good enough to flush them. Calling
2815                  * synchornize_rcu_tasks() will wait for those tasks to
2816                  * execute and either schedule voluntarily or enter user space.
2817                  */
2818                 if (IS_ENABLED(CONFIG_PREEMPTION))
2819                         synchronize_rcu_tasks();
2820 
2821  free_ops:
2822                 arch_ftrace_trampoline_free(ops);
2823         }
2824 
2825         return 0;
2826 }
2827 
2828 static void ftrace_startup_sysctl(void)
2829 {
2830         int command;
2831 
2832         if (unlikely(ftrace_disabled))
2833                 return;
2834 
2835         /* Force update next time */
2836         saved_ftrace_func = NULL;
2837         /* ftrace_start_up is true if we want ftrace running */
2838         if (ftrace_start_up) {
2839                 command = FTRACE_UPDATE_CALLS;
2840                 if (ftrace_graph_active)
2841                         command |= FTRACE_START_FUNC_RET;
2842                 ftrace_startup_enable(command);
2843         }
2844 }
2845 
2846 static void ftrace_shutdown_sysctl(void)
2847 {
2848         int command;
2849 
2850         if (unlikely(ftrace_disabled))
2851                 return;
2852 
2853         /* ftrace_start_up is true if ftrace is running */
2854         if (ftrace_start_up) {
2855                 command = FTRACE_DISABLE_CALLS;
2856                 if (ftrace_graph_active)
2857                         command |= FTRACE_STOP_FUNC_RET;
2858                 ftrace_run_update_code(command);
2859         }
2860 }
2861 
2862 static u64              ftrace_update_time;
2863 unsigned long           ftrace_update_tot_cnt;
2864 
2865 static inline int ops_traces_mod(struct ftrace_ops *ops)
2866 {
2867         /*
2868          * Filter_hash being empty will default to trace module.
2869          * But notrace hash requires a test of individual module functions.
2870          */
2871         return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2872                 ftrace_hash_empty(ops->func_hash->notrace_hash);
2873 }
2874 
2875 /*
2876  * Check if the current ops references the record.
2877  *
2878  * If the ops traces all functions, then it was already accounted for.
2879  * If the ops does not trace the current record function, skip it.
2880  * If the ops ignores the function via notrace filter, skip it.
2881  */
2882 static inline bool
2883 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2884 {
2885         /* If ops isn't enabled, ignore it */
2886         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2887                 return false;
2888 
2889         /* If ops traces all then it includes this function */
2890         if (ops_traces_mod(ops))
2891                 return true;
2892 
2893         /* The function must be in the filter */
2894         if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2895             !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2896                 return false;
2897 
2898         /* If in notrace hash, we ignore it too */
2899         if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2900                 return false;
2901 
2902         return true;
2903 }
2904 
2905 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2906 {
2907         struct ftrace_page *pg;
2908         struct dyn_ftrace *p;
2909         u64 start, stop;
2910         unsigned long update_cnt = 0;
2911         unsigned long rec_flags = 0;
2912         int i;
2913 
2914         start = ftrace_now(raw_smp_processor_id());
2915 
2916         /*
2917          * When a module is loaded, this function is called to convert
2918          * the calls to mcount in its text to nops, and also to create
2919          * an entry in the ftrace data. Now, if ftrace is activated
2920          * after this call, but before the module sets its text to
2921          * read-only, the modification of enabling ftrace can fail if
2922          * the read-only is done while ftrace is converting the calls.
2923          * To prevent this, the module's records are set as disabled
2924          * and will be enabled after the call to set the module's text
2925          * to read-only.
2926          */
2927         if (mod)
2928                 rec_flags |= FTRACE_FL_DISABLED;
2929 
2930         for (pg = new_pgs; pg; pg = pg->next) {
2931 
2932                 for (i = 0; i < pg->index; i++) {
2933 
2934                         /* If something went wrong, bail without enabling anything */
2935                         if (unlikely(ftrace_disabled))
2936                                 return -1;
2937 
2938                         p = &pg->records[i];
2939                         p->flags = rec_flags;
2940 
2941                         /*
2942                          * Do the initial record conversion from mcount jump
2943                          * to the NOP instructions.
2944                          */
2945                         if (!__is_defined(CC_USING_NOP_MCOUNT) &&
2946                             !ftrace_code_disable(mod, p))
2947                                 break;
2948 
2949                         update_cnt++;
2950                 }
2951         }
2952 
2953         stop = ftrace_now(raw_smp_processor_id());
2954         ftrace_update_time = stop - start;
2955         ftrace_update_tot_cnt += update_cnt;
2956 
2957         return 0;
2958 }
2959 
2960 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2961 {
2962         int order;
2963         int cnt;
2964 
2965         if (WARN_ON(!count))
2966                 return -EINVAL;
2967 
2968         order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2969 
2970         /*
2971          * We want to fill as much as possible. No more than a page
2972          * may be empty.
2973          */
2974         while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2975                 order--;
2976 
2977  again:
2978         pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2979 
2980         if (!pg->records) {
2981                 /* if we can't allocate this size, try something smaller */
2982                 if (!order)
2983                         return -ENOMEM;
2984                 order >>= 1;
2985                 goto again;
2986         }
2987 
2988         cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2989         pg->size = cnt;
2990 
2991         if (cnt > count)
2992                 cnt = count;
2993 
2994         return cnt;
2995 }
2996 
2997 static struct ftrace_page *
2998 ftrace_allocate_pages(unsigned long num_to_init)
2999 {
3000         struct ftrace_page *start_pg;
3001         struct ftrace_page *pg;
3002         int order;
3003         int cnt;
3004 
3005         if (!num_to_init)
3006                 return NULL;
3007 
3008         start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3009         if (!pg)
3010                 return NULL;
3011 
3012         /*
3013          * Try to allocate as much as possible in one continues
3014          * location that fills in all of the space. We want to
3015          * waste as little space as possible.
3016          */
3017         for (;;) {
3018                 cnt = ftrace_allocate_records(pg, num_to_init);
3019                 if (cnt < 0)
3020                         goto free_pages;
3021 
3022                 num_to_init -= cnt;
3023                 if (!num_to_init)
3024                         break;
3025 
3026                 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3027                 if (!pg->next)
3028                         goto free_pages;
3029 
3030                 pg = pg->next;
3031         }
3032 
3033         return start_pg;
3034 
3035  free_pages:
3036         pg = start_pg;
3037         while (pg) {
3038                 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3039                 free_pages((unsigned long)pg->records, order);
3040                 start_pg = pg->next;
3041                 kfree(pg);
3042                 pg = start_pg;
3043         }
3044         pr_info("ftrace: FAILED to allocate memory for functions\n");
3045         return NULL;
3046 }
3047 
3048 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3049 
3050 struct ftrace_iterator {
3051         loff_t                          pos;
3052         loff_t                          func_pos;
3053         loff_t                          mod_pos;
3054         struct ftrace_page              *pg;
3055         struct dyn_ftrace               *func;
3056         struct ftrace_func_probe        *probe;
3057         struct ftrace_func_entry        *probe_entry;
3058         struct trace_parser             parser;
3059         struct ftrace_hash              *hash;
3060         struct ftrace_ops               *ops;
3061         struct trace_array              *tr;
3062         struct list_head                *mod_list;
3063         int                             pidx;
3064         int                             idx;
3065         unsigned                        flags;
3066 };
3067 
3068 static void *
3069 t_probe_next(struct seq_file *m, loff_t *pos)
3070 {
3071         struct ftrace_iterator *iter = m->private;
3072         struct trace_array *tr = iter->ops->private;
3073         struct list_head *func_probes;
3074         struct ftrace_hash *hash;
3075         struct list_head *next;
3076         struct hlist_node *hnd = NULL;
3077         struct hlist_head *hhd;
3078         int size;
3079 
3080         (*pos)++;
3081         iter->pos = *pos;
3082 
3083         if (!tr)
3084                 return NULL;
3085 
3086         func_probes = &tr->func_probes;
3087         if (list_empty(func_probes))
3088                 return NULL;
3089 
3090         if (!iter->probe) {
3091                 next = func_probes->next;
3092                 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3093         }
3094 
3095         if (iter->probe_entry)
3096                 hnd = &iter->probe_entry->hlist;
3097 
3098         hash = iter->probe->ops.func_hash->filter_hash;
3099 
3100         /*
3101          * A probe being registered may temporarily have an empty hash
3102          * and it's at the end of the func_probes list.
3103          */
3104         if (!hash || hash == EMPTY_HASH)
3105                 return NULL;
3106 
3107         size = 1 << hash->size_bits;
3108 
3109  retry:
3110         if (iter->pidx >= size) {
3111                 if (iter->probe->list.next == func_probes)
3112                         return NULL;
3113                 next = iter->probe->list.next;
3114                 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3115                 hash = iter->probe->ops.func_hash->filter_hash;
3116                 size = 1 << hash->size_bits;
3117                 iter->pidx = 0;
3118         }
3119 
3120         hhd = &hash->buckets[iter->pidx];
3121 
3122         if (hlist_empty(hhd)) {
3123                 iter->pidx++;
3124                 hnd = NULL;
3125                 goto retry;
3126         }
3127 
3128         if (!hnd)
3129                 hnd = hhd->first;
3130         else {
3131                 hnd = hnd->next;
3132                 if (!hnd) {
3133                         iter->pidx++;
3134                         goto retry;
3135                 }
3136         }
3137 
3138         if (WARN_ON_ONCE(!hnd))
3139                 return NULL;
3140 
3141         iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3142 
3143         return iter;
3144 }
3145 
3146 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3147 {
3148         struct ftrace_iterator *iter = m->private;
3149         void *p = NULL;
3150         loff_t l;
3151 
3152         if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3153                 return NULL;
3154 
3155         if (iter->mod_pos > *pos)
3156                 return NULL;
3157 
3158         iter->probe = NULL;
3159         iter->probe_entry = NULL;
3160         iter->pidx = 0;
3161         for (l = 0; l <= (*pos - iter->mod_pos); ) {
3162                 p = t_probe_next(m, &l);
3163                 if (!p)
3164                         break;
3165         }
3166         if (!p)
3167                 return NULL;
3168 
3169         /* Only set this if we have an item */
3170         iter->flags |= FTRACE_ITER_PROBE;
3171 
3172         return iter;
3173 }
3174 
3175 static int
3176 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3177 {
3178         struct ftrace_func_entry *probe_entry;
3179         struct ftrace_probe_ops *probe_ops;
3180         struct ftrace_func_probe *probe;
3181 
3182         probe = iter->probe;
3183         probe_entry = iter->probe_entry;
3184 
3185         if (WARN_ON_ONCE(!probe || !probe_entry))
3186                 return -EIO;
3187 
3188         probe_ops = probe->probe_ops;
3189 
3190         if (probe_ops->print)
3191                 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3192 
3193         seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3194                    (void *)probe_ops->func);
3195 
3196         return 0;
3197 }
3198 
3199 static void *
3200 t_mod_next(struct seq_file *m, loff_t *pos)
3201 {
3202         struct ftrace_iterator *iter = m->private;
3203         struct trace_array *tr = iter->tr;
3204 
3205         (*pos)++;
3206         iter->pos = *pos;
3207 
3208         iter->mod_list = iter->mod_list->next;
3209 
3210         if (iter->mod_list == &tr->mod_trace ||
3211             iter->mod_list == &tr->mod_notrace) {
3212                 iter->flags &= ~FTRACE_ITER_MOD;
3213                 return NULL;
3214         }
3215 
3216         iter->mod_pos = *pos;
3217 
3218         return iter;
3219 }
3220 
3221 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3222 {
3223         struct ftrace_iterator *iter = m->private;
3224         void *p = NULL;
3225         loff_t l;
3226 
3227         if (iter->func_pos > *pos)
3228                 return NULL;
3229 
3230         iter->mod_pos = iter->func_pos;
3231 
3232         /* probes are only available if tr is set */
3233         if (!iter->tr)
3234                 return NULL;
3235 
3236         for (l = 0; l <= (*pos - iter->func_pos); ) {
3237                 p = t_mod_next(m, &l);
3238                 if (!p)
3239                         break;
3240         }
3241         if (!p) {
3242                 iter->flags &= ~FTRACE_ITER_MOD;
3243                 return t_probe_start(m, pos);
3244         }
3245 
3246         /* Only set this if we have an item */
3247         iter->flags |= FTRACE_ITER_MOD;
3248 
3249         return iter;
3250 }
3251 
3252 static int
3253 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3254 {
3255         struct ftrace_mod_load *ftrace_mod;
3256         struct trace_array *tr = iter->tr;
3257 
3258         if (WARN_ON_ONCE(!iter->mod_list) ||
3259                          iter->mod_list == &tr->mod_trace ||
3260                          iter->mod_list == &tr->mod_notrace)
3261                 return -EIO;
3262 
3263         ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3264 
3265         if (ftrace_mod->func)
3266                 seq_printf(m, "%s", ftrace_mod->func);
3267         else
3268                 seq_putc(m, '*');
3269 
3270         seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3271 
3272         return 0;
3273 }
3274 
3275 static void *
3276 t_func_next(struct seq_file *m, loff_t *pos)
3277 {
3278         struct ftrace_iterator *iter = m->private;
3279         struct dyn_ftrace *rec = NULL;
3280 
3281         (*pos)++;
3282 
3283  retry:
3284         if (iter->idx >= iter->pg->index) {
3285                 if (iter->pg->next) {
3286                         iter->pg = iter->pg->next;
3287                         iter->idx = 0;
3288                         goto retry;
3289                 }
3290         } else {
3291                 rec = &iter->pg->records[iter->idx++];
3292                 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3293                      !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3294 
3295                     ((iter->flags & FTRACE_ITER_ENABLED) &&
3296                      !(rec->flags & FTRACE_FL_ENABLED))) {
3297 
3298                         rec = NULL;
3299                         goto retry;
3300                 }
3301         }
3302 
3303         if (!rec)
3304                 return NULL;
3305 
3306         iter->pos = iter->func_pos = *pos;
3307         iter->func = rec;
3308 
3309         return iter;
3310 }
3311 
3312 static void *
3313 t_next(struct seq_file *m, void *v, loff_t *pos)
3314 {
3315         struct ftrace_iterator *iter = m->private;
3316         loff_t l = *pos; /* t_probe_start() must use original pos */
3317         void *ret;
3318 
3319         if (unlikely(ftrace_disabled))
3320                 return NULL;
3321 
3322         if (iter->flags & FTRACE_ITER_PROBE)
3323                 return t_probe_next(m, pos);
3324 
3325         if (iter->flags & FTRACE_ITER_MOD)
3326                 return t_mod_next(m, pos);
3327 
3328         if (iter->flags & FTRACE_ITER_PRINTALL) {
3329                 /* next must increment pos, and t_probe_start does not */
3330                 (*pos)++;
3331                 return t_mod_start(m, &l);
3332         }
3333 
3334         ret = t_func_next(m, pos);
3335 
3336         if (!ret)
3337                 return t_mod_start(m, &l);
3338 
3339         return ret;
3340 }
3341 
3342 static void reset_iter_read(struct ftrace_iterator *iter)
3343 {
3344         iter->pos = 0;
3345         iter->func_pos = 0;
3346         iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3347 }
3348 
3349 static void *t_start(struct seq_file *m, loff_t *pos)
3350 {
3351         struct ftrace_iterator *iter = m->private;
3352         void *p = NULL;
3353         loff_t l;
3354 
3355         mutex_lock(&ftrace_lock);
3356 
3357         if (unlikely(ftrace_disabled))
3358                 return NULL;
3359 
3360         /*
3361          * If an lseek was done, then reset and start from beginning.
3362          */
3363         if (*pos < iter->pos)
3364                 reset_iter_read(iter);
3365 
3366         /*
3367          * For set_ftrace_filter reading, if we have the filter
3368          * off, we can short cut and just print out that all
3369          * functions are enabled.
3370          */
3371         if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3372             ftrace_hash_empty(iter->hash)) {
3373                 iter->func_pos = 1; /* Account for the message */
3374                 if (*pos > 0)
3375                         return t_mod_start(m, pos);
3376                 iter->flags |= FTRACE_ITER_PRINTALL;
3377                 /* reset in case of seek/pread */
3378                 iter->flags &= ~FTRACE_ITER_PROBE;
3379                 return iter;
3380         }
3381 
3382         if (iter->flags & FTRACE_ITER_MOD)
3383                 return t_mod_start(m, pos);
3384 
3385         /*
3386          * Unfortunately, we need to restart at ftrace_pages_start
3387          * every time we let go of the ftrace_mutex. This is because
3388          * those pointers can change without the lock.
3389          */
3390         iter->pg = ftrace_pages_start;
3391         iter->idx = 0;
3392         for (l = 0; l <= *pos; ) {
3393                 p = t_func_next(m, &l);
3394                 if (!p)
3395                         break;
3396         }
3397 
3398         if (!p)
3399                 return t_mod_start(m, pos);
3400 
3401         return iter;
3402 }
3403 
3404 static void t_stop(struct seq_file *m, void *p)
3405 {
3406         mutex_unlock(&ftrace_lock);
3407 }
3408 
3409 void * __weak
3410 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3411 {
3412         return NULL;
3413 }
3414 
3415 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3416                                 struct dyn_ftrace *rec)
3417 {
3418         void *ptr;
3419 
3420         ptr = arch_ftrace_trampoline_func(ops, rec);
3421         if (ptr)
3422                 seq_printf(m, " ->%pS", ptr);
3423 }
3424 
3425 static int t_show(struct seq_file *m, void *v)
3426 {
3427         struct ftrace_iterator *iter = m->private;
3428         struct dyn_ftrace *rec;
3429 
3430         if (iter->flags & FTRACE_ITER_PROBE)
3431                 return t_probe_show(m, iter);
3432 
3433         if (iter->flags & FTRACE_ITER_MOD)
3434                 return t_mod_show(m, iter);
3435 
3436         if (iter->flags & FTRACE_ITER_PRINTALL) {
3437                 if (iter->flags & FTRACE_ITER_NOTRACE)
3438                         seq_puts(m, "#### no functions disabled ####\n");
3439                 else
3440                         seq_puts(m, "#### all functions enabled ####\n");
3441                 return 0;
3442         }
3443 
3444         rec = iter->func;
3445 
3446         if (!rec)
3447                 return 0;
3448 
3449         seq_printf(m, "%ps", (void *)rec->ip);
3450         if (iter->flags & FTRACE_ITER_ENABLED) {
3451                 struct ftrace_ops *ops;
3452 
3453                 seq_printf(m, " (%ld)%s%s",
3454                            ftrace_rec_count(rec),
3455                            rec->flags & FTRACE_FL_REGS ? " R" : "  ",
3456                            rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ");
3457                 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3458                         ops = ftrace_find_tramp_ops_any(rec);
3459                         if (ops) {
3460                                 do {
3461                                         seq_printf(m, "\ttramp: %pS (%pS)",
3462                                                    (void *)ops->trampoline,
3463                                                    (void *)ops->func);
3464                                         add_trampoline_func(m, ops, rec);
3465                                         ops = ftrace_find_tramp_ops_next(rec, ops);
3466                                 } while (ops);
3467                         } else
3468                                 seq_puts(m, "\ttramp: ERROR!");
3469                 } else {
3470                         add_trampoline_func(m, NULL, rec);
3471                 }
3472         }       
3473 
3474         seq_putc(m, '\n');
3475 
3476         return 0;
3477 }
3478 
3479 static const struct seq_operations show_ftrace_seq_ops = {
3480         .start = t_start,
3481         .next = t_next,
3482         .stop = t_stop,
3483         .show = t_show,
3484 };
3485 
3486 static int
3487 ftrace_avail_open(struct inode *inode, struct file *file)
3488 {
3489         struct ftrace_iterator *iter;
3490         int ret;
3491 
3492         ret = security_locked_down(LOCKDOWN_TRACEFS);
3493         if (ret)
3494                 return ret;
3495 
3496         if (unlikely(ftrace_disabled))
3497                 return -ENODEV;
3498 
3499         iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3500         if (!iter)
3501                 return -ENOMEM;
3502 
3503         iter->pg = ftrace_pages_start;
3504         iter->ops = &global_ops;
3505 
3506         return 0;
3507 }
3508 
3509 static int
3510 ftrace_enabled_open(struct inode *inode, struct file *file)
3511 {
3512         struct ftrace_iterator *iter;
3513 
3514         /*
3515          * This shows us what functions are currently being
3516          * traced and by what. Not sure if we want lockdown
3517          * to hide such critical information for an admin.
3518          * Although, perhaps it can show information we don't
3519          * want people to see, but if something is tracing
3520          * something, we probably want to know about it.
3521          */
3522 
3523         iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3524         if (!iter)
3525                 return -ENOMEM;
3526 
3527         iter->pg = ftrace_pages_start;
3528         iter->flags = FTRACE_ITER_ENABLED;
3529         iter->ops = &global_ops;
3530 
3531         return 0;
3532 }
3533 
3534 /**
3535  * ftrace_regex_open - initialize function tracer filter files
3536  * @ops: The ftrace_ops that hold the hash filters
3537  * @flag: The type of filter to process
3538  * @inode: The inode, usually passed in to your open routine
3539  * @file: The file, usually passed in to your open routine
3540  *
3541  * ftrace_regex_open() initializes the filter files for the
3542  * @ops. Depending on @flag it may process the filter hash or
3543  * the notrace hash of @ops. With this called from the open
3544  * routine, you can use ftrace_filter_write() for the write
3545  * routine if @flag has FTRACE_ITER_FILTER set, or
3546  * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3547  * tracing_lseek() should be used as the lseek routine, and
3548  * release must call ftrace_regex_release().
3549  */
3550 int
3551 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3552                   struct inode *inode, struct file *file)
3553 {
3554         struct ftrace_iterator *iter;
3555         struct ftrace_hash *hash;
3556         struct list_head *mod_head;
3557         struct trace_array *tr = ops->private;
3558         int ret = -ENOMEM;
3559 
3560         ftrace_ops_init(ops);
3561 
3562         if (unlikely(ftrace_disabled))
3563                 return -ENODEV;
3564 
3565         if (tracing_check_open_get_tr(tr))
3566                 return -ENODEV;
3567 
3568         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3569         if (!iter)
3570                 goto out;
3571 
3572         if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3573                 goto out;
3574 
3575         iter->ops = ops;
3576         iter->flags = flag;
3577         iter->tr = tr;
3578 
3579         mutex_lock(&ops->func_hash->regex_lock);
3580 
3581         if (flag & FTRACE_ITER_NOTRACE) {
3582                 hash = ops->func_hash->notrace_hash;
3583                 mod_head = tr ? &tr->mod_notrace : NULL;
3584         } else {
3585                 hash = ops->func_hash->filter_hash;
3586                 mod_head = tr ? &tr->mod_trace : NULL;
3587         }
3588 
3589         iter->mod_list = mod_head;
3590 
3591         if (file->f_mode & FMODE_WRITE) {
3592                 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3593 
3594                 if (file->f_flags & O_TRUNC) {
3595                         iter->hash = alloc_ftrace_hash(size_bits);
3596                         clear_ftrace_mod_list(mod_head);
3597                 } else {
3598                         iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3599                 }
3600 
3601                 if (!iter->hash) {
3602                         trace_parser_put(&iter->parser);
3603                         goto out_unlock;
3604                 }
3605         } else
3606                 iter->hash = hash;
3607 
3608         ret = 0;
3609 
3610         if (file->f_mode & FMODE_READ) {
3611                 iter->pg = ftrace_pages_start;
3612 
3613                 ret = seq_open(file, &show_ftrace_seq_ops);
3614                 if (!ret) {
3615                         struct seq_file *m = file->private_data;
3616                         m->private = iter;
3617                 } else {
3618                         /* Failed */
3619                         free_ftrace_hash(iter->hash);
3620                         trace_parser_put(&iter->parser);
3621                 }
3622         } else
3623                 file->private_data = iter;
3624 
3625  out_unlock:
3626         mutex_unlock(&ops->func_hash->regex_lock);
3627 
3628  out:
3629         if (ret) {
3630                 kfree(iter);
3631                 if (tr)
3632                         trace_array_put(tr);
3633         }
3634 
3635         return ret;
3636 }
3637 
3638 static int
3639 ftrace_filter_open(struct inode *inode, struct file *file)
3640 {
3641         struct ftrace_ops *ops = inode->i_private;
3642 
3643         /* Checks for tracefs lockdown */
3644         return ftrace_regex_open(ops,
3645                         FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3646                         inode, file);
3647 }
3648 
3649 static int
3650 ftrace_notrace_open(struct inode *inode, struct file *file)
3651 {
3652         struct ftrace_ops *ops = inode->i_private;
3653 
3654         /* Checks for tracefs lockdown */
3655         return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3656                                  inode, file);
3657 }
3658 
3659 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3660 struct ftrace_glob {
3661         char *search;
3662         unsigned len;
3663         int type;
3664 };
3665 
3666 /*
3667  * If symbols in an architecture don't correspond exactly to the user-visible
3668  * name of what they represent, it is possible to define this function to
3669  * perform the necessary adjustments.
3670 */
3671 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3672 {
3673         return str;
3674 }
3675 
3676 static int ftrace_match(char *str, struct ftrace_glob *g)
3677 {
3678         int matched = 0;
3679         int slen;
3680 
3681         str = arch_ftrace_match_adjust(str, g->search);
3682 
3683         switch (g->type) {
3684         case MATCH_FULL:
3685                 if (strcmp(str, g->search) == 0)
3686                         matched = 1;
3687                 break;
3688         case MATCH_FRONT_ONLY:
3689                 if (strncmp(str, g->search, g->len) == 0)
3690                         matched = 1;
3691                 break;
3692         case MATCH_MIDDLE_ONLY:
3693                 if (strstr(str, g->search))
3694                         matched = 1;
3695                 break;
3696         case MATCH_END_ONLY:
3697                 slen = strlen(str);
3698                 if (slen >= g->len &&
3699                     memcmp(str + slen - g->len, g->search, g->len) == 0)
3700                         matched = 1;
3701                 break;
3702         case MATCH_GLOB:
3703                 if (glob_match(g->search, str))
3704                         matched = 1;
3705                 break;
3706         }
3707 
3708         return matched;
3709 }
3710 
3711 static int
3712 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3713 {
3714         struct ftrace_func_entry *entry;
3715         int ret = 0;
3716 
3717         entry = ftrace_lookup_ip(hash, rec->ip);
3718         if (clear_filter) {
3719                 /* Do nothing if it doesn't exist */
3720                 if (!entry)
3721                         return 0;
3722 
3723                 free_hash_entry(hash, entry);
3724         } else {
3725                 /* Do nothing if it exists */
3726                 if (entry)
3727                         return 0;
3728 
3729                 ret = add_hash_entry(hash, rec->ip);
3730         }
3731         return ret;
3732 }
3733 
3734 static int
3735 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3736                  int clear_filter)
3737 {
3738         long index = simple_strtoul(func_g->search, NULL, 0);
3739         struct ftrace_page *pg;
3740         struct dyn_ftrace *rec;
3741 
3742         /* The index starts at 1 */
3743         if (--index < 0)
3744                 return 0;
3745 
3746         do_for_each_ftrace_rec(pg, rec) {
3747                 if (pg->index <= index) {
3748                         index -= pg->index;
3749                         /* this is a double loop, break goes to the next page */
3750                         break;
3751                 }
3752                 rec = &pg->records[index];
3753                 enter_record(hash, rec, clear_filter);
3754                 return 1;
3755         } while_for_each_ftrace_rec();
3756         return 0;
3757 }
3758 
3759 static int
3760 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3761                 struct ftrace_glob *mod_g, int exclude_mod)
3762 {
3763         char str[KSYM_SYMBOL_LEN];
3764         char *modname;
3765 
3766         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3767 
3768         if (mod_g) {
3769                 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3770 
3771                 /* blank module name to match all modules */
3772                 if (!mod_g->len) {
3773                         /* blank module globbing: modname xor exclude_mod */
3774                         if (!exclude_mod != !modname)
3775                                 goto func_match;
3776                         return 0;
3777                 }
3778 
3779                 /*
3780                  * exclude_mod is set to trace everything but the given
3781                  * module. If it is set and the module matches, then
3782                  * return 0. If it is not set, and the module doesn't match
3783                  * also return 0. Otherwise, check the function to see if
3784                  * that matches.
3785                  */
3786                 if (!mod_matches == !exclude_mod)
3787                         return 0;
3788 func_match:
3789                 /* blank search means to match all funcs in the mod */
3790                 if (!func_g->len)
3791                         return 1;
3792         }
3793 
3794         return ftrace_match(str, func_g);
3795 }
3796 
3797 static int
3798 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3799 {
3800         struct ftrace_page *pg;
3801         struct dyn_ftrace *rec;
3802         struct ftrace_glob func_g = { .type = MATCH_FULL };
3803         struct ftrace_glob mod_g = { .type = MATCH_FULL };
3804         struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3805         int exclude_mod = 0;
3806         int found = 0;
3807         int ret;
3808         int clear_filter = 0;
3809 
3810         if (func) {
3811                 func_g.type = filter_parse_regex(func, len, &func_g.search,
3812                                                  &clear_filter);
3813                 func_g.len = strlen(func_g.search);
3814         }
3815 
3816         if (mod) {
3817                 mod_g.type = filter_parse_regex(mod, strlen(mod),
3818                                 &mod_g.search, &exclude_mod);
3819                 mod_g.len = strlen(mod_g.search);
3820         }
3821 
3822         mutex_lock(&ftrace_lock);
3823 
3824         if (unlikely(ftrace_disabled))
3825                 goto out_unlock;
3826 
3827         if (func_g.type == MATCH_INDEX) {
3828                 found = add_rec_by_index(hash, &func_g, clear_filter);
3829                 goto out_unlock;
3830         }
3831 
3832         do_for_each_ftrace_rec(pg, rec) {
3833 
3834                 if (rec->flags & FTRACE_FL_DISABLED)
3835                         continue;
3836 
3837                 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3838                         ret = enter_record(hash, rec, clear_filter);
3839                         if (ret < 0) {
3840                                 found = ret;
3841                                 goto out_unlock;
3842                         }
3843                         found = 1;
3844                 }
3845         } while_for_each_ftrace_rec();
3846  out_unlock:
3847         mutex_unlock(&ftrace_lock);
3848 
3849         return found;
3850 }
3851 
3852 static int
3853 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3854 {
3855         return match_records(hash, buff, len, NULL);
3856 }
3857 
3858 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3859                                    struct ftrace_ops_hash *old_hash)
3860 {
3861         struct ftrace_ops *op;
3862 
3863         if (!ftrace_enabled)
3864                 return;
3865 
3866         if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3867                 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3868                 return;
3869         }
3870 
3871         /*
3872          * If this is the shared global_ops filter, then we need to
3873          * check if there is another ops that shares it, is enabled.
3874          * If so, we still need to run the modify code.
3875          */
3876         if (ops->func_hash != &global_ops.local_hash)
3877                 return;
3878 
3879         do_for_each_ftrace_op(op, ftrace_ops_list) {
3880                 if (op->func_hash == &global_ops.local_hash &&
3881                     op->flags & FTRACE_OPS_FL_ENABLED) {
3882                         ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3883                         /* Only need to do this once */
3884                         return;
3885                 }
3886         } while_for_each_ftrace_op(op);
3887 }
3888 
3889 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3890                                            struct ftrace_hash **orig_hash,
3891                                            struct ftrace_hash *hash,
3892                                            int enable)
3893 {
3894         struct ftrace_ops_hash old_hash_ops;
3895         struct ftrace_hash *old_hash;
3896         int ret;
3897 
3898         old_hash = *orig_hash;
3899         old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3900         old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3901         ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3902         if (!ret) {
3903                 ftrace_ops_update_code(ops, &old_hash_ops);
3904                 free_ftrace_hash_rcu(old_hash);
3905         }
3906         return ret;
3907 }
3908 
3909 static bool module_exists(const char *module)
3910 {
3911         /* All modules have the symbol __this_module */
3912         static const char this_mod[] = "__this_module";
3913         char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
3914         unsigned long val;
3915         int n;
3916 
3917         n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
3918 
3919         if (n > sizeof(modname) - 1)
3920                 return false;
3921 
3922         val = module_kallsyms_lookup_name(modname);
3923         return val != 0;
3924 }
3925 
3926 static int cache_mod(struct trace_array *tr,
3927                      const char *func, char *module, int enable)
3928 {
3929         struct ftrace_mod_load *ftrace_mod, *n;
3930         struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
3931         int ret;
3932 
3933         mutex_lock(&ftrace_lock);
3934 
3935         /* We do not cache inverse filters */
3936         if (func[0] == '!') {
3937                 func++;
3938                 ret = -EINVAL;
3939 
3940                 /* Look to remove this hash */
3941                 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3942                         if (strcmp(ftrace_mod->module, module) != 0)
3943                                 continue;
3944 
3945                         /* no func matches all */
3946                         if (strcmp(func, "*") == 0 ||
3947                             (ftrace_mod->func &&
3948                              strcmp(ftrace_mod->func, func) == 0)) {
3949                                 ret = 0;
3950                                 free_ftrace_mod(ftrace_mod);
3951                                 continue;
3952                         }
3953                 }
3954                 goto out;
3955         }
3956 
3957         ret = -EINVAL;
3958         /* We only care about modules that have not been loaded yet */
3959         if (module_exists(module))
3960                 goto out;
3961 
3962         /* Save this string off, and execute it when the module is loaded */
3963         ret = ftrace_add_mod(tr, func, module, enable);
3964  out:
3965         mutex_unlock(&ftrace_lock);
3966 
3967         return ret;
3968 }
3969 
3970 static int
3971 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3972                  int reset, int enable);
3973 
3974 #ifdef CONFIG_MODULES
3975 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
3976                              char *mod, bool enable)
3977 {
3978         struct ftrace_mod_load *ftrace_mod, *n;
3979         struct ftrace_hash **orig_hash, *new_hash;
3980         LIST_HEAD(process_mods);
3981         char *func;
3982         int ret;
3983 
3984         mutex_lock(&ops->func_hash->regex_lock);
3985 
3986         if (enable)
3987                 orig_hash = &ops->func_hash->filter_hash;
3988         else
3989                 orig_hash = &ops->func_hash->notrace_hash;
3990 
3991         new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
3992                                               *orig_hash);
3993         if (!new_hash)
3994                 goto out; /* warn? */
3995 
3996         mutex_lock(&ftrace_lock);
3997 
3998         list_for_each_entry_safe(ftrace_mod, n, head, list) {
3999 
4000                 if (strcmp(ftrace_mod->module, mod) != 0)
4001                         continue;
4002 
4003                 if (ftrace_mod->func)
4004                         func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4005                 else
4006                         func = kstrdup("*", GFP_KERNEL);
4007 
4008                 if (!func) /* warn? */
4009                         continue;
4010 
4011                 list_del(&ftrace_mod->list);
4012                 list_add(&ftrace_mod->list, &process_mods);
4013 
4014                 /* Use the newly allocated func, as it may be "*" */
4015                 kfree(ftrace_mod->func);
4016                 ftrace_mod->func = func;
4017         }
4018 
4019         mutex_unlock(&ftrace_lock);
4020 
4021         list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4022 
4023                 func = ftrace_mod->func;
4024 
4025                 /* Grabs ftrace_lock, which is why we have this extra step */
4026                 match_records(new_hash, func, strlen(func), mod);
4027                 free_ftrace_mod(ftrace_mod);
4028         }
4029 
4030         if (enable && list_empty(head))
4031                 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4032 
4033         mutex_lock(&ftrace_lock);
4034 
4035         ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4036                                               new_hash, enable);
4037         mutex_unlock(&ftrace_lock);
4038 
4039  out:
4040         mutex_unlock(&ops->func_hash->regex_lock);
4041 
4042         free_ftrace_hash(new_hash);
4043 }
4044 
4045 static void process_cached_mods(const char *mod_name)
4046 {
4047         struct trace_array *tr;
4048         char *mod;
4049 
4050         mod = kstrdup(mod_name, GFP_KERNEL);
4051         if (!mod)
4052                 return;
4053 
4054         mutex_lock(&trace_types_lock);
4055         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4056                 if (!list_empty(&tr->mod_trace))
4057                         process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4058                 if (!list_empty(&tr->mod_notrace))
4059                         process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4060         }
4061         mutex_unlock(&trace_types_lock);
4062 
4063         kfree(mod);
4064 }
4065 #endif
4066 
4067 /*
4068  * We register the module command as a template to show others how
4069  * to register the a command as well.
4070  */
4071 
4072 static int
4073 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4074                     char *func_orig, char *cmd, char *module, int enable)
4075 {
4076         char *func;
4077         int ret;
4078 
4079         /* match_records() modifies func, and we need the original */
4080         func = kstrdup(func_orig, GFP_KERNEL);
4081         if (!func)
4082                 return -ENOMEM;
4083 
4084         /*
4085          * cmd == 'mod' because we only registered this func
4086          * for the 'mod' ftrace_func_command.
4087          * But if you register one func with multiple commands,
4088          * you can tell which command was used by the cmd
4089          * parameter.
4090          */
4091         ret = match_records(hash, func, strlen(func), module);
4092         kfree(func);
4093 
4094         if (!ret)
4095                 return cache_mod(tr, func_orig, module, enable);
4096         if (ret < 0)
4097                 return ret;
4098         return 0;
4099 }
4100 
4101 static struct ftrace_func_command ftrace_mod_cmd = {
4102         .name                   = "mod",
4103         .func                   = ftrace_mod_callback,
4104 };
4105 
4106 static int __init ftrace_mod_cmd_init(void)
4107 {
4108         return register_ftrace_command(&ftrace_mod_cmd);
4109 }
4110 core_initcall(ftrace_mod_cmd_init);
4111 
4112 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4113                                       struct ftrace_ops *op, struct pt_regs *pt_regs)
4114 {
4115         struct ftrace_probe_ops *probe_ops;
4116         struct ftrace_func_probe *probe;
4117 
4118         probe = container_of(op, struct ftrace_func_probe, ops);
4119         probe_ops = probe->probe_ops;
4120 
4121         /*
4122          * Disable preemption for these calls to prevent a RCU grace
4123          * period. This syncs the hash iteration and freeing of items
4124          * on the hash. rcu_read_lock is too dangerous here.
4125          */
4126         preempt_disable_notrace();
4127         probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4128         preempt_enable_notrace();
4129 }
4130 
4131 struct ftrace_func_map {
4132         struct ftrace_func_entry        entry;
4133         void                            *data;
4134 };
4135 
4136 struct ftrace_func_mapper {
4137         struct ftrace_hash              hash;
4138 };
4139 
4140 /**
4141  * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4142  *
4143  * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4144  */
4145 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4146 {
4147         struct ftrace_hash *hash;
4148 
4149         /*
4150          * The mapper is simply a ftrace_hash, but since the entries
4151          * in the hash are not ftrace_func_entry type, we define it
4152          * as a separate structure.
4153          */
4154         hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4155         return (struct ftrace_func_mapper *)hash;
4156 }
4157 
4158 /**
4159  * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4160  * @mapper: The mapper that has the ip maps
4161  * @ip: the instruction pointer to find the data for
4162  *
4163  * Returns the data mapped to @ip if found otherwise NULL. The return
4164  * is actually the address of the mapper data pointer. The address is
4165  * returned for use cases where the data is no bigger than a long, and
4166  * the user can use the data pointer as its data instead of having to
4167  * allocate more memory for the reference.
4168  */
4169 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4170                                   unsigned long ip)
4171 {
4172         struct ftrace_func_entry *entry;
4173         struct ftrace_func_map *map;
4174 
4175         entry = ftrace_lookup_ip(&mapper->hash, ip);
4176         if (!entry)
4177                 return NULL;
4178 
4179         map = (struct ftrace_func_map *)entry;
4180         return &map->data;
4181 }
4182 
4183 /**
4184  * ftrace_func_mapper_add_ip - Map some data to an ip
4185  * @mapper: The mapper that has the ip maps
4186  * @ip: The instruction pointer address to map @data to
4187  * @data: The data to map to @ip
4188  *
4189  * Returns 0 on succes otherwise an error.
4190  */
4191 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4192                               unsigned long ip, void *data)
4193 {
4194         struct ftrace_func_entry *entry;
4195         struct ftrace_func_map *map;
4196 
4197         entry = ftrace_lookup_ip(&mapper->hash, ip);
4198         if (entry)
4199                 return -EBUSY;
4200 
4201         map = kmalloc(sizeof(*map), GFP_KERNEL);
4202         if (!map)
4203                 return -ENOMEM;
4204 
4205         map->entry.ip = ip;
4206         map->data = data;
4207 
4208         __add_hash_entry(&mapper->hash, &map->entry);
4209 
4210         return 0;
4211 }
4212 
4213 /**
4214  * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4215  * @mapper: The mapper that has the ip maps
4216  * @ip: The instruction pointer address to remove the data from
4217  *
4218  * Returns the data if it is found, otherwise NULL.
4219  * Note, if the data pointer is used as the data itself, (see 
4220  * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4221  * if the data pointer was set to zero.
4222  */
4223 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4224                                    unsigned long ip)
4225 {
4226         struct ftrace_func_entry *entry;
4227         struct ftrace_func_map *map;
4228         void *data;
4229 
4230         entry = ftrace_lookup_ip(&mapper->hash, ip);
4231         if (!entry)
4232                 return NULL;
4233 
4234         map = (struct ftrace_func_map *)entry;
4235         data = map->data;
4236 
4237         remove_hash_entry(&mapper->hash, entry);
4238         kfree(entry);
4239 
4240         return data;
4241 }
4242 
4243 /**
4244  * free_ftrace_func_mapper - free a mapping of ips and data
4245  * @mapper: The mapper that has the ip maps
4246  * @free_func: A function to be called on each data item.
4247  *
4248  * This is used to free the function mapper. The @free_func is optional
4249  * and can be used if the data needs to be freed as well.
4250  */
4251 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4252                              ftrace_mapper_func free_func)
4253 {
4254         struct ftrace_func_entry *entry;
4255         struct ftrace_func_map *map;
4256         struct hlist_head *hhd;
4257         int size, i;
4258 
4259         if (!mapper)
4260                 return;
4261 
4262         if (free_func && mapper->hash.count) {
4263                 size = 1 << mapper->hash.size_bits;
4264                 for (i = 0; i < size; i++) {
4265                         hhd = &mapper->hash.buckets[i];
4266                         hlist_for_each_entry(entry, hhd, hlist) {
4267                                 map = (struct ftrace_func_map *)entry;
4268                                 free_func(map);
4269                         }
4270                 }
4271         }
4272         free_ftrace_hash(&mapper->hash);
4273 }
4274 
4275 static void release_probe(struct ftrace_func_probe *probe)
4276 {
4277         struct ftrace_probe_ops *probe_ops;
4278 
4279         mutex_lock(&ftrace_lock);
4280 
4281         WARN_ON(probe->ref <= 0);
4282 
4283         /* Subtract the ref that was used to protect this instance */
4284         probe->ref--;
4285 
4286         if (!probe->ref) {
4287                 probe_ops = probe->probe_ops;
4288                 /*
4289                  * Sending zero as ip tells probe_ops to free
4290                  * the probe->data itself
4291                  */
4292                 if (probe_ops->free)
4293                         probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4294                 list_del(&probe->list);
4295                 kfree(probe);
4296         }
4297         mutex_unlock(&ftrace_lock);
4298 }
4299 
4300 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4301 {
4302         /*
4303          * Add one ref to keep it from being freed when releasing the
4304          * ftrace_lock mutex.
4305          */
4306         probe->ref++;
4307 }
4308 
4309 int
4310 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4311                                struct ftrace_probe_ops *probe_ops,
4312                                void *data)
4313 {
4314         struct ftrace_func_entry *entry;
4315         struct ftrace_func_probe *probe;
4316         struct ftrace_hash **orig_hash;
4317         struct ftrace_hash *old_hash;
4318         struct ftrace_hash *hash;
4319         int count = 0;
4320         int size;
4321         int ret;
4322         int i;
4323 
4324         if (WARN_ON(!tr))
4325                 return -EINVAL;
4326 
4327         /* We do not support '!' for function probes */
4328         if (WARN_ON(glob[0] == '!'))
4329                 return -EINVAL;
4330 
4331 
4332         mutex_lock(&ftrace_lock);
4333         /* Check if the probe_ops is already registered */
4334         list_for_each_entry(probe, &tr->func_probes, list) {
4335                 if (probe->probe_ops == probe_ops)
4336                         break;
4337         }
4338         if (&probe->list == &tr->func_probes) {
4339                 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4340                 if (!probe) {
4341                         mutex_unlock(&ftrace_lock);
4342                         return -ENOMEM;
4343                 }
4344                 probe->probe_ops = probe_ops;
4345                 probe->ops.func = function_trace_probe_call;
4346                 probe->tr = tr;
4347                 ftrace_ops_init(&probe->ops);
4348                 list_add(&probe->list, &tr->func_probes);
4349         }
4350 
4351         acquire_probe_locked(probe);
4352 
4353         mutex_unlock(&ftrace_lock);
4354 
4355         /*
4356          * Note, there's a small window here that the func_hash->filter_hash
4357          * may be NULL or empty. Need to be carefule when reading the loop.
4358          */
4359         mutex_lock(&probe->ops.func_hash->regex_lock);
4360 
4361         orig_hash = &probe->ops.func_hash->filter_hash;
4362         old_hash = *orig_hash;
4363         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4364 
4365         if (!hash) {
4366                 ret = -ENOMEM;
4367                 goto out;
4368         }
4369 
4370         ret = ftrace_match_records(hash, glob, strlen(glob));
4371 
4372         /* Nothing found? */
4373         if (!ret)
4374                 ret = -EINVAL;
4375 
4376         if (ret < 0)
4377                 goto out;
4378 
4379         size = 1 << hash->size_bits;
4380         for (i = 0; i < size; i++) {
4381                 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4382                         if (ftrace_lookup_ip(old_hash, entry->ip))
4383                                 continue;
4384                         /*
4385                          * The caller might want to do something special
4386                          * for each function we find. We call the callback
4387                          * to give the caller an opportunity to do so.
4388                          */
4389                         if (probe_ops->init) {
4390                                 ret = probe_ops->init(probe_ops, tr,
4391                                                       entry->ip, data,
4392                                                       &probe->data);
4393                                 if (ret < 0) {
4394                                         if (probe_ops->free && count)
4395                                                 probe_ops->free(probe_ops, tr,
4396                                                                 0, probe->data);
4397                                         probe->data = NULL;
4398                                         goto out;
4399                                 }
4400                         }
4401                         count++;
4402                 }
4403         }
4404 
4405         mutex_lock(&ftrace_lock);
4406 
4407         if (!count) {
4408                 /* Nothing was added? */
4409                 ret = -EINVAL;
4410                 goto out_unlock;
4411         }
4412 
4413         ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4414                                               hash, 1);
4415         if (ret < 0)
4416                 goto err_unlock;
4417 
4418         /* One ref for each new function traced */
4419         probe->ref += count;
4420 
4421         if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4422                 ret = ftrace_startup(&probe->ops, 0);
4423 
4424  out_unlock:
4425         mutex_unlock(&ftrace_lock);
4426 
4427         if (!ret)
4428                 ret = count;
4429  out:
4430         mutex_unlock(&probe->ops.func_hash->regex_lock);
4431         free_ftrace_hash(hash);
4432 
4433         release_probe(probe);
4434 
4435         return ret;
4436 
4437  err_unlock:
4438         if (!probe_ops->free || !count)
4439                 goto out_unlock;
4440 
4441         /* Failed to do the move, need to call the free functions */
4442         for (i = 0; i < size; i++) {
4443                 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4444                         if (ftrace_lookup_ip(old_hash, entry->ip))
4445                                 continue;
4446                         probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4447                 }
4448         }
4449         goto out_unlock;
4450 }
4451 
4452 int
4453 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4454                                       struct ftrace_probe_ops *probe_ops)
4455 {
4456         struct ftrace_ops_hash old_hash_ops;
4457         struct ftrace_func_entry *entry;
4458         struct ftrace_func_probe *probe;
4459         struct ftrace_glob func_g;
4460         struct ftrace_hash **orig_hash;
4461         struct ftrace_hash *old_hash;
4462         struct ftrace_hash *hash = NULL;
4463         struct hlist_node *tmp;
4464         struct hlist_head hhd;
4465         char str[KSYM_SYMBOL_LEN];
4466         int count = 0;
4467         int i, ret = -ENODEV;
4468         int size;
4469 
4470         if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4471                 func_g.search = NULL;
4472         else {
4473                 int not;
4474 
4475                 func_g.type = filter_parse_regex(glob, strlen(glob),
4476                                                  &func_g.search, &not);
4477                 func_g.len = strlen(func_g.search);
4478 
4479                 /* we do not support '!' for function probes */
4480                 if (WARN_ON(not))
4481                         return -EINVAL;
4482         }
4483 
4484         mutex_lock(&ftrace_lock);
4485         /* Check if the probe_ops is already registered */
4486         list_for_each_entry(probe, &tr->func_probes, list) {
4487                 if (probe->probe_ops == probe_ops)
4488                         break;
4489         }
4490         if (&probe->list == &tr->func_probes)
4491                 goto err_unlock_ftrace;
4492 
4493         ret = -EINVAL;
4494         if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4495                 goto err_unlock_ftrace;
4496 
4497         acquire_probe_locked(probe);
4498 
4499         mutex_unlock(&ftrace_lock);
4500 
4501         mutex_lock(&probe->ops.func_hash->regex_lock);
4502 
4503         orig_hash = &probe->ops.func_hash->filter_hash;
4504         old_hash = *orig_hash;
4505 
4506         if (ftrace_hash_empty(old_hash))
4507                 goto out_unlock;
4508 
4509         old_hash_ops.filter_hash = old_hash;
4510         /* Probes only have filters */
4511         old_hash_ops.notrace_hash = NULL;
4512 
4513         ret = -ENOMEM;
4514         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4515         if (!hash)
4516                 goto out_unlock;
4517 
4518         INIT_HLIST_HEAD(&hhd);
4519 
4520         size = 1 << hash->size_bits;
4521         for (i = 0; i < size; i++) {
4522                 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4523 
4524                         if (func_g.search) {
4525                                 kallsyms_lookup(entry->ip, NULL, NULL,
4526                                                 NULL, str);
4527                                 if (!ftrace_match(str, &func_g))
4528                                         continue;
4529                         }
4530                         count++;
4531                         remove_hash_entry(hash, entry);
4532                         hlist_add_head(&entry->hlist, &hhd);
4533                 }
4534         }
4535 
4536         /* Nothing found? */
4537         if (!count) {
4538                 ret = -EINVAL;
4539                 goto out_unlock;
4540         }
4541 
4542         mutex_lock(&ftrace_lock);
4543 
4544         WARN_ON(probe->ref < count);
4545 
4546         probe->ref -= count;
4547 
4548         if (ftrace_hash_empty(hash))
4549                 ftrace_shutdown(&probe->ops, 0);
4550 
4551         ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4552                                               hash, 1);
4553 
4554         /* still need to update the function call sites */
4555         if (ftrace_enabled && !ftrace_hash_empty(hash))
4556                 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4557                                        &old_hash_ops);
4558         synchronize_rcu();
4559 
4560         hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4561                 hlist_del(&entry->hlist);
4562                 if (probe_ops->free)
4563                         probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4564                 kfree(entry);
4565         }
4566         mutex_unlock(&ftrace_lock);
4567 
4568  out_unlock:
4569         mutex_unlock(&probe->ops.func_hash->regex_lock);
4570         free_ftrace_hash(hash);
4571 
4572         release_probe(probe);
4573 
4574         return ret;
4575 
4576  err_unlock_ftrace:
4577         mutex_unlock(&ftrace_lock);
4578         return ret;
4579 }
4580 
4581 void clear_ftrace_function_probes(struct trace_array *tr)
4582 {
4583         struct ftrace_func_probe *probe, *n;
4584 
4585         list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4586                 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4587 }
4588 
4589 static LIST_HEAD(ftrace_commands);
4590 static DEFINE_MUTEX(ftrace_cmd_mutex);
4591 
4592 /*
4593  * Currently we only register ftrace commands from __init, so mark this
4594  * __init too.
4595  */
4596 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4597 {
4598         struct ftrace_func_command *p;
4599         int ret = 0;
4600 
4601         mutex_lock(&ftrace_cmd_mutex);
4602         list_for_each_entry(p, &ftrace_commands, list) {
4603                 if (strcmp(cmd->name, p->name) == 0) {
4604                         ret = -EBUSY;
4605                         goto out_unlock;
4606                 }
4607         }
4608         list_add(&cmd->list, &ftrace_commands);
4609  out_unlock:
4610         mutex_unlock(&ftrace_cmd_mutex);
4611 
4612         return ret;
4613 }
4614 
4615 /*
4616  * Currently we only unregister ftrace commands from __init, so mark
4617  * this __init too.
4618  */
4619 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4620 {
4621         struct ftrace_func_command *p, *n;
4622         int ret = -ENODEV;
4623 
4624         mutex_lock(&ftrace_cmd_mutex);
4625         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4626                 if (strcmp(cmd->name, p->name) == 0) {
4627                         ret = 0;
4628                         list_del_init(&p->list);
4629                         goto out_unlock;
4630                 }
4631         }
4632  out_unlock:
4633         mutex_unlock(&ftrace_cmd_mutex);
4634 
4635         return ret;
4636 }
4637 
4638 static int ftrace_process_regex(struct ftrace_iterator *iter,
4639                                 char *buff, int len, int enable)
4640 {
4641         struct ftrace_hash *hash = iter->hash;
4642         struct trace_array *tr = iter->ops->private;
4643         char *func, *command, *next = buff;
4644         struct ftrace_func_command *p;
4645         int ret = -EINVAL;
4646 
4647         func = strsep(&next, ":");
4648 
4649         if (!next) {
4650                 ret = ftrace_match_records(hash, func, len);
4651                 if (!ret)
4652                         ret = -EINVAL;
4653                 if (ret < 0)
4654                         return ret;
4655                 return 0;
4656         }
4657 
4658         /* command found */
4659 
4660         command = strsep(&next, ":");
4661 
4662         mutex_lock(&ftrace_cmd_mutex);
4663         list_for_each_entry(p, &ftrace_commands, list) {
4664                 if (strcmp(p->name, command) == 0) {
4665                         ret = p->func(tr, hash, func, command, next, enable);
4666                         goto out_unlock;
4667                 }
4668         }
4669  out_unlock:
4670         mutex_unlock(&ftrace_cmd_mutex);
4671 
4672         return ret;
4673 }
4674 
4675 static ssize_t
4676 ftrace_regex_write(struct file *file, const char __user *ubuf,
4677                    size_t cnt, loff_t *ppos, int enable)
4678 {
4679         struct ftrace_iterator *iter;
4680         struct trace_parser *parser;
4681         ssize_t ret, read;
4682 
4683         if (!cnt)
4684                 return 0;
4685 
4686         if (file->f_mode & FMODE_READ) {
4687                 struct seq_file *m = file->private_data;
4688                 iter = m->private;
4689         } else
4690                 iter = file->private_data;
4691 
4692         if (unlikely(ftrace_disabled))
4693                 return -ENODEV;
4694 
4695         /* iter->hash is a local copy, so we don't need regex_lock */
4696 
4697         parser = &iter->parser;
4698         read = trace_get_user(parser, ubuf, cnt, ppos);
4699 
4700         if (read >= 0 && trace_parser_loaded(parser) &&
4701             !trace_parser_cont(parser)) {
4702                 ret = ftrace_process_regex(iter, parser->buffer,
4703                                            parser->idx, enable);
4704                 trace_parser_clear(parser);
4705                 if (ret < 0)
4706                         goto out;
4707         }
4708 
4709         ret = read;
4710  out:
4711         return ret;
4712 }
4713 
4714 ssize_t
4715 ftrace_filter_write(struct file *file, const char __user *ubuf,
4716                     size_t cnt, loff_t *ppos)
4717 {
4718         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4719 }
4720 
4721 ssize_t
4722 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4723                      size_t cnt, loff_t *ppos)
4724 {
4725         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4726 }
4727 
4728 static int
4729 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4730 {
4731         struct ftrace_func_entry *entry;
4732 
4733         if (!ftrace_location(ip))
4734                 return -EINVAL;
4735 
4736         if (remove) {
4737                 entry = ftrace_lookup_ip(hash, ip);
4738                 if (!entry)
4739                         return -ENOENT;
4740                 free_hash_entry(hash, entry);
4741                 return 0;
4742         }
4743 
4744         return add_hash_entry(hash, ip);
4745 }
4746 
4747 static int
4748 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4749                 unsigned long ip, int remove, int reset, int enable)
4750 {
4751         struct ftrace_hash **orig_hash;
4752         struct ftrace_hash *hash;
4753         int ret;
4754 
4755         if (unlikely(ftrace_disabled))
4756                 return -ENODEV;
4757 
4758         mutex_lock(&ops->func_hash->regex_lock);
4759 
4760         if (enable)
4761                 orig_hash = &ops->func_hash->filter_hash;
4762         else
4763                 orig_hash = &ops->func_hash->notrace_hash;
4764 
4765         if (reset)
4766                 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4767         else
4768                 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4769 
4770         if (!hash) {
4771                 ret = -ENOMEM;
4772                 goto out_regex_unlock;
4773         }
4774 
4775         if (buf && !ftrace_match_records(hash, buf, len)) {
4776                 ret = -EINVAL;
4777                 goto out_regex_unlock;
4778         }
4779         if (ip) {
4780                 ret = ftrace_match_addr(hash, ip, remove);
4781                 if (ret < 0)
4782                         goto out_regex_unlock;
4783         }
4784 
4785         mutex_lock(&ftrace_lock);
4786         ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4787         mutex_unlock(&ftrace_lock);
4788 
4789  out_regex_unlock:
4790         mutex_unlock(&ops->func_hash->regex_lock);
4791 
4792         free_ftrace_hash(hash);
4793         return ret;
4794 }
4795 
4796 static int
4797 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4798                 int reset, int enable)
4799 {
4800         return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
4801 }
4802 
4803 /**
4804  * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4805  * @ops - the ops to set the filter with
4806  * @ip - the address to add to or remove from the filter.
4807  * @remove - non zero to remove the ip from the filter
4808  * @reset - non zero to reset all filters before applying this filter.
4809  *
4810  * Filters denote which functions should be enabled when tracing is enabled
4811  * If @ip is NULL, it failes to update filter.
4812  */
4813 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4814                          int remove, int reset)
4815 {
4816         ftrace_ops_init(ops);
4817         return ftrace_set_addr(ops, ip, remove, reset, 1);
4818 }
4819 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4820 
4821 /**
4822  * ftrace_ops_set_global_filter - setup ops to use global filters
4823  * @ops - the ops which will use the global filters
4824  *
4825  * ftrace users who need global function trace filtering should call this.
4826  * It can set the global filter only if ops were not initialized before.
4827  */
4828 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4829 {
4830         if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4831                 return;
4832 
4833         ftrace_ops_init(ops);
4834         ops->func_hash = &global_ops.local_hash;
4835 }
4836 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4837 
4838 static int
4839 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4840                  int reset, int enable)
4841 {
4842         return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4843 }
4844 
4845 /**
4846  * ftrace_set_filter - set a function to filter on in ftrace
4847  * @ops - the ops to set the filter with
4848  * @buf - the string that holds the function filter text.
4849  * @len - the length of the string.
4850  * @reset - non zero to reset all filters before applying this filter.
4851  *
4852  * Filters denote which functions should be enabled when tracing is enabled.
4853  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4854  */
4855 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4856                        int len, int reset)
4857 {
4858         ftrace_ops_init(ops);
4859         return ftrace_set_regex(ops, buf, len, reset, 1);
4860 }
4861 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4862 
4863 /**
4864  * ftrace_set_notrace - set a function to not trace in ftrace
4865  * @ops - the ops to set the notrace filter with
4866  * @buf - the string that holds the function notrace text.
4867  * @len - the length of the string.
4868  * @reset - non zero to reset all filters before applying this filter.
4869  *
4870  * Notrace Filters denote which functions should not be enabled when tracing
4871  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4872  * for tracing.
4873  */
4874 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4875                         int len, int reset)
4876 {
4877         ftrace_ops_init(ops);
4878         return ftrace_set_regex(ops, buf, len, reset, 0);
4879 }
4880 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4881 /**
4882  * ftrace_set_global_filter - set a function to filter on with global tracers
4883  * @buf - the string that holds the function filter text.
4884  * @len - the length of the string.
4885  * @reset - non zero to reset all filters before applying this filter.
4886  *
4887  * Filters denote which functions should be enabled when tracing is enabled.
4888  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4889  */
4890 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4891 {
4892         ftrace_set_regex(&global_ops, buf, len, reset, 1);
4893 }
4894 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4895 
4896 /**
4897  * ftrace_set_global_notrace - set a function to not trace with global tracers
4898  * @buf - the string that holds the function notrace text.
4899  * @len - the length of the string.
4900  * @reset - non zero to reset all filters before applying this filter.
4901  *
4902  * Notrace Filters denote which functions should not be enabled when tracing
4903  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4904  * for tracing.
4905  */
4906 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4907 {
4908         ftrace_set_regex(&global_ops, buf, len, reset, 0);
4909 }
4910 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4911 
4912 /*
4913  * command line interface to allow users to set filters on boot up.
4914  */
4915 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
4916 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4917 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4918 
4919 /* Used by function selftest to not test if filter is set */
4920 bool ftrace_filter_param __initdata;
4921 
4922 static int __init set_ftrace_notrace(char *str)
4923 {
4924         ftrace_filter_param = true;
4925         strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4926         return 1;
4927 }
4928 __setup("ftrace_notrace=", set_ftrace_notrace);
4929 
4930 static int __init set_ftrace_filter(char *str)
4931 {
4932         ftrace_filter_param = true;
4933         strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4934         return 1;
4935 }
4936 __setup("ftrace_filter=", set_ftrace_filter);
4937 
4938 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4939 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4940 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4941 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4942 
4943 static int __init set_graph_function(char *str)
4944 {
4945         strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4946         return 1;
4947 }
4948 __setup("ftrace_graph_filter=", set_graph_function);
4949 
4950 static int __init set_graph_notrace_function(char *str)
4951 {
4952         strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4953         return 1;
4954 }
4955 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
4956 
4957 static int __init set_graph_max_depth_function(char *str)
4958 {
4959         if (!str)
4960                 return 0;
4961         fgraph_max_depth = simple_strtoul(str, NULL, 0);
4962         return 1;
4963 }
4964 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
4965 
4966 static void __init set_ftrace_early_graph(char *buf, int enable)
4967 {
4968         int ret;
4969         char *func;
4970         struct ftrace_hash *hash;
4971 
4972         hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4973         if (WARN_ON(!hash))
4974                 return;
4975 
4976         while (buf) {
4977                 func = strsep(&buf, ",");
4978                 /* we allow only one expression at a time */
4979                 ret = ftrace_graph_set_hash(hash, func);
4980                 if (ret)
4981                         printk(KERN_DEBUG "ftrace: function %s not "
4982                                           "traceable\n", func);
4983         }
4984 
4985         if (enable)
4986                 ftrace_graph_hash = hash;
4987         else
4988                 ftrace_graph_notrace_hash = hash;
4989 }
4990 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4991 
4992 void __init
4993 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4994 {
4995         char *func;
4996 
4997         ftrace_ops_init(ops);
4998 
4999         while (buf) {
5000                 func = strsep(&buf, ",");
5001                 ftrace_set_regex(ops, func, strlen(func), 0, enable);
5002         }
5003 }
5004 
5005 static void __init set_ftrace_early_filters(void)
5006 {
5007         if (ftrace_filter_buf[0])
5008                 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5009         if (ftrace_notrace_buf[0])
5010                 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5011 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5012         if (ftrace_graph_buf[0])
5013                 set_ftrace_early_graph(ftrace_graph_buf, 1);
5014         if (ftrace_graph_notrace_buf[0])
5015                 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5016 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5017 }
5018 
5019 int ftrace_regex_release(struct inode *inode, struct file *file)
5020 {
5021         struct seq_file *m = (struct seq_file *)file->private_data;
5022         struct ftrace_iterator *iter;
5023         struct ftrace_hash **orig_hash;
5024         struct trace_parser *parser;
5025         int filter_hash;
5026         int ret;
5027 
5028         if (file->f_mode & FMODE_READ) {
5029                 iter = m->private;
5030                 seq_release(inode, file);
5031         } else
5032                 iter = file->private_data;
5033 
5034         parser = &iter->parser;
5035         if (trace_parser_loaded(parser)) {
5036                 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5037         }
5038 
5039         trace_parser_put(parser);
5040 
5041         mutex_lock(&iter->ops->func_hash->regex_lock);
5042 
5043         if (file->f_mode & FMODE_WRITE) {
5044                 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5045 
5046                 if (filter_hash) {
5047                         orig_hash = &iter->ops->func_hash->filter_hash;
5048                         if (iter->tr && !list_empty(&iter->tr->mod_trace))
5049                                 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5050                 } else
5051                         orig_hash = &iter->ops->func_hash->notrace_hash;
5052 
5053                 mutex_lock(&ftrace_lock);
5054                 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5055                                                       iter->hash, filter_hash);
5056                 mutex_unlock(&ftrace_lock);
5057         } else {
5058                 /* For read only, the hash is the ops hash */
5059                 iter->hash = NULL;
5060         }
5061 
5062         mutex_unlock(&iter->ops->func_hash->regex_lock);
5063         free_ftrace_hash(iter->hash);
5064         if (iter->tr)
5065                 trace_array_put(iter->tr);
5066         kfree(iter);
5067 
5068         return 0;
5069 }
5070 
5071 static const struct file_operations ftrace_avail_fops = {
5072         .open = ftrace_avail_open,
5073         .read = seq_read,
5074         .llseek = seq_lseek,
5075         .release = seq_release_private,
5076 };
5077 
5078 static const struct file_operations ftrace_enabled_fops = {
5079         .open = ftrace_enabled_open,
5080         .read = seq_read,
5081         .llseek = seq_lseek,
5082         .release = seq_release_private,
5083 };
5084 
5085 static const struct file_operations ftrace_filter_fops = {
5086         .open = ftrace_filter_open,
5087         .read = seq_read,
5088         .write = ftrace_filter_write,
5089         .llseek = tracing_lseek,
5090         .release = ftrace_regex_release,
5091 };
5092 
5093 static const struct file_operations ftrace_notrace_fops = {
5094         .open = ftrace_notrace_open,
5095         .read = seq_read,
5096         .write = ftrace_notrace_write,
5097         .llseek = tracing_lseek,
5098         .release = ftrace_regex_release,
5099 };
5100 
5101 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5102 
5103 static DEFINE_MUTEX(graph_lock);
5104 
5105 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5106 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5107 
5108 enum graph_filter_type {
5109         GRAPH_FILTER_NOTRACE    = 0,
5110         GRAPH_FILTER_FUNCTION,
5111 };
5112 
5113 #define FTRACE_GRAPH_EMPTY      ((void *)1)
5114 
5115 struct ftrace_graph_data {
5116         struct ftrace_hash              *hash;
5117         struct ftrace_func_entry        *entry;
5118         int                             idx;   /* for hash table iteration */
5119         enum graph_filter_type          type;
5120         struct ftrace_hash              *new_hash;
5121         const struct seq_operations     *seq_ops;
5122         struct trace_parser             parser;
5123 };
5124 
5125 static void *
5126 __g_next(struct seq_file *m, loff_t *pos)
5127 {
5128         struct ftrace_graph_data *fgd = m->private;
5129         struct ftrace_func_entry *entry = fgd->entry;
5130         struct hlist_head *head;
5131         int i, idx = fgd->idx;
5132 
5133         if (*pos >= fgd->hash->count)
5134                 return NULL;
5135 
5136         if (entry) {
5137                 hlist_for_each_entry_continue(entry, hlist) {
5138                         fgd->entry = entry;
5139                         return entry;
5140                 }
5141 
5142                 idx++;
5143         }
5144 
5145         for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5146                 head = &fgd->hash->buckets[i];
5147                 hlist_for_each_entry(entry, head, hlist) {
5148                         fgd->entry = entry;
5149                         fgd->idx = i;
5150                         return entry;
5151                 }
5152         }
5153         return NULL;
5154 }
5155 
5156 static void *
5157 g_next(struct seq_file *m, void *v, loff_t *pos)
5158 {
5159         (*pos)++;
5160         return __g_next(m, pos);
5161 }
5162 
5163 static void *g_start(struct seq_file *m, loff_t *pos)
5164 {
5165         struct ftrace_graph_data *fgd = m->private;
5166 
5167         mutex_lock(&graph_lock);
5168 
5169         if (fgd->type == GRAPH_FILTER_FUNCTION)
5170                 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5171                                         lockdep_is_held(&graph_lock));
5172         else
5173                 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5174                                         lockdep_is_held(&graph_lock));
5175 
5176         /* Nothing, tell g_show to print all functions are enabled */
5177         if (ftrace_hash_empty(fgd->hash) && !*pos)
5178                 return FTRACE_GRAPH_EMPTY;
5179 
5180         fgd->idx = 0;
5181         fgd->entry = NULL;
5182         return __g_next(m, pos);
5183 }
5184 
5185 static void g_stop(struct seq_file *m, void *p)
5186 {
5187         mutex_unlock(&graph_lock);
5188 }
5189 
5190 static int g_show(struct seq_file *m, void *v)
5191 {
5192         struct ftrace_func_entry *entry = v;
5193 
5194         if (!entry)
5195                 return 0;
5196 
5197         if (entry == FTRACE_GRAPH_EMPTY) {
5198                 struct ftrace_graph_data *fgd = m->private;
5199 
5200                 if (fgd->type == GRAPH_FILTER_FUNCTION)
5201                         seq_puts(m, "#### all functions enabled ####\n");
5202                 else
5203                         seq_puts(m, "#### no functions disabled ####\n");
5204                 return 0;
5205         }
5206 
5207         seq_printf(m, "%ps\n", (void *)entry->ip);
5208 
5209         return 0;
5210 }
5211 
5212 static const struct seq_operations ftrace_graph_seq_ops = {
5213         .start = g_start,
5214         .next = g_next,
5215         .stop = g_stop,
5216         .show = g_show,
5217 };
5218 
5219 static int
5220 __ftrace_graph_open(struct inode *inode, struct file *file,
5221                     struct ftrace_graph_data *fgd)
5222 {
5223         int ret;
5224         struct ftrace_hash *new_hash = NULL;
5225 
5226         ret = security_locked_down(LOCKDOWN_TRACEFS);
5227         if (ret)
5228                 return ret;
5229 
5230         if (file->f_mode & FMODE_WRITE) {
5231                 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5232 
5233                 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5234                         return -ENOMEM;
5235 
5236                 if (file->f_flags & O_TRUNC)
5237                         new_hash = alloc_ftrace_hash(size_bits);
5238                 else
5239                         new_hash = alloc_and_copy_ftrace_hash(size_bits,
5240                                                               fgd->hash);
5241                 if (!new_hash) {
5242                         ret = -ENOMEM;
5243                         goto out;
5244                 }
5245         }
5246 
5247         if (file->f_mode & FMODE_READ) {
5248                 ret = seq_open(file, &ftrace_graph_seq_ops);
5249                 if (!ret) {
5250                         struct seq_file *m = file->private_data;
5251                         m->private = fgd;
5252                 } else {
5253                         /* Failed */
5254                         free_ftrace_hash(new_hash);
5255                         new_hash = NULL;
5256                 }
5257         } else
5258                 file->private_data = fgd;
5259 
5260 out:
5261         if (ret < 0 && file->f_mode & FMODE_WRITE)
5262                 trace_parser_put(&fgd->parser);
5263 
5264         fgd->new_hash = new_hash;
5265 
5266         /*
5267          * All uses of fgd->hash must be taken with the graph_lock
5268          * held. The graph_lock is going to be released, so force
5269          * fgd->hash to be reinitialized when it is taken again.
5270          */
5271         fgd->hash = NULL;
5272 
5273         return ret;
5274 }
5275 
5276 static int
5277 ftrace_graph_open(struct inode *inode, struct file *file)
5278 {
5279         struct ftrace_graph_data *fgd;
5280         int ret;
5281 
5282         if (unlikely(ftrace_disabled))
5283                 return -ENODEV;
5284 
5285         fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5286         if (fgd == NULL)
5287                 return -ENOMEM;
5288 
5289         mutex_lock(&graph_lock);
5290 
5291         fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5292                                         lockdep_is_held(&graph_lock));
5293         fgd->type = GRAPH_FILTER_FUNCTION;
5294         fgd->seq_ops = &ftrace_graph_seq_ops;
5295 
5296         ret = __ftrace_graph_open(inode, file, fgd);
5297         if (ret < 0)
5298                 kfree(fgd);
5299 
5300         mutex_unlock(&graph_lock);
5301         return ret;
5302 }
5303 
5304 static int
5305 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5306 {
5307         struct ftrace_graph_data *fgd;
5308         int ret;
5309 
5310         if (unlikely(ftrace_disabled))
5311                 return -ENODEV;
5312 
5313         fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5314         if (fgd == NULL)
5315                 return -ENOMEM;
5316 
5317         mutex_lock(&graph_lock);
5318 
5319         fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5320                                         lockdep_is_held(&graph_lock));
5321         fgd->type = GRAPH_FILTER_NOTRACE;
5322         fgd->seq_ops = &ftrace_graph_seq_ops;
5323 
5324         ret = __ftrace_graph_open(inode, file, fgd);
5325         if (ret < 0)
5326                 kfree(fgd);
5327 
5328         mutex_unlock(&graph_lock);
5329         return ret;
5330 }
5331 
5332 static int
5333 ftrace_graph_release(struct inode *inode, struct file *file)
5334 {
5335         struct ftrace_graph_data *fgd;
5336         struct ftrace_hash *old_hash, *new_hash;
5337         struct trace_parser *parser;
5338         int ret = 0;
5339 
5340         if (file->f_mode & FMODE_READ) {
5341                 struct seq_file *m = file->private_data;
5342 
5343                 fgd = m->private;
5344                 seq_release(inode, file);
5345         } else {
5346                 fgd = file->private_data;
5347         }
5348 
5349 
5350         if (file->f_mode & FMODE_WRITE) {
5351 
5352                 parser = &fgd->parser;
5353 
5354                 if (trace_parser_loaded((parser))) {
5355                         ret = ftrace_graph_set_hash(fgd->new_hash,
5356                                                     parser->buffer);
5357                 }
5358 
5359                 trace_parser_put(parser);
5360 
5361                 new_hash = __ftrace_hash_move(fgd->new_hash);
5362                 if (!new_hash) {
5363                         ret = -ENOMEM;
5364                         goto out;
5365                 }
5366 
5367                 mutex_lock(&graph_lock);
5368 
5369                 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5370                         old_hash = rcu_dereference_protected(ftrace_graph_hash,
5371                                         lockdep_is_held(&graph_lock));
5372                         rcu_assign_pointer(ftrace_graph_hash, new_hash);
5373                 } else {
5374                         old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5375                                         lockdep_is_held(&graph_lock));
5376                         rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5377                 }
5378 
5379                 mutex_unlock(&graph_lock);
5380 
5381                 /*
5382                  * We need to do a hard force of sched synchronization.
5383                  * This is because we use preempt_disable() to do RCU, but
5384                  * the function tracers can be called where RCU is not watching
5385                  * (like before user_exit()). We can not rely on the RCU
5386                  * infrastructure to do the synchronization, thus we must do it
5387                  * ourselves.
5388                  */
5389                 schedule_on_each_cpu(ftrace_sync);
5390 
5391                 free_ftrace_hash(old_hash);
5392         }
5393 
5394  out:
5395         free_ftrace_hash(fgd->new_hash);
5396         kfree(fgd);
5397 
5398         return ret;
5399 }
5400 
5401 static int
5402 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5403 {
5404         struct ftrace_glob func_g;
5405         struct dyn_ftrace *rec;
5406         struct ftrace_page *pg;
5407         struct ftrace_func_entry *entry;
5408         int fail = 1;
5409         int not;
5410 
5411         /* decode regex */
5412         func_g.type = filter_parse_regex(buffer, strlen(buffer),
5413                                          &func_g.search, &not);
5414 
5415         func_g.len = strlen(func_g.search);
5416 
5417         mutex_lock(&ftrace_lock);
5418 
5419         if (unlikely(ftrace_disabled)) {
5420                 mutex_unlock(&ftrace_lock);
5421                 return -ENODEV;
5422         }
5423 
5424         do_for_each_ftrace_rec(pg, rec) {
5425 
5426                 if (rec->flags & FTRACE_FL_DISABLED)
5427                         continue;
5428 
5429                 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5430                         entry = ftrace_lookup_ip(hash, rec->ip);
5431 
5432                         if (!not) {
5433                                 fail = 0;
5434 
5435                                 if (entry)
5436                                         continue;
5437                                 if (add_hash_entry(hash, rec->ip) < 0)
5438                                         goto out;
5439                         } else {
5440                                 if (entry) {
5441                                         free_hash_entry(hash, entry);
5442                                         fail = 0;
5443                                 }
5444                         }
5445                 }
5446         } while_for_each_ftrace_rec();
5447 out:
5448         mutex_unlock(&ftrace_lock);
5449 
5450         if (fail)
5451                 return -EINVAL;
5452 
5453         return 0;
5454 }
5455 
5456 static ssize_t
5457 ftrace_graph_write(struct file *file, const char __user *ubuf,
5458                    size_t cnt, loff_t *ppos)
5459 {
5460         ssize_t read, ret = 0;
5461         struct ftrace_graph_data *fgd = file->private_data;
5462         struct trace_parser *parser;
5463 
5464         if (!cnt)
5465                 return 0;
5466 
5467         /* Read mode uses seq functions */
5468         if (file->f_mode & FMODE_READ) {
5469                 struct seq_file *m = file->private_data;
5470                 fgd = m->private;
5471         }
5472 
5473         parser = &fgd->parser;
5474 
5475         read = trace_get_user(parser, ubuf, cnt, ppos);
5476 
5477         if (read >= 0 && trace_parser_loaded(parser) &&
5478             !trace_parser_cont(parser)) {
5479 
5480                 ret = ftrace_graph_set_hash(fgd->new_hash,
5481                                             parser->buffer);
5482                 trace_parser_clear(parser);
5483         }
5484 
5485         if (!ret)
5486                 ret = read;
5487 
5488         return ret;
5489 }
5490 
5491 static const struct file_operations ftrace_graph_fops = {
5492         .open           = ftrace_graph_open,
5493         .read           = seq_read,
5494         .write          = ftrace_graph_write,
5495         .llseek         = tracing_lseek,
5496         .release        = ftrace_graph_release,
5497 };
5498 
5499 static const struct file_operations ftrace_graph_notrace_fops = {
5500         .open           = ftrace_graph_notrace_open,
5501         .read           = seq_read,
5502         .write          = ftrace_graph_write,
5503         .llseek         = tracing_lseek,
5504         .release        = ftrace_graph_release,
5505 };
5506 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5507 
5508 void ftrace_create_filter_files(struct ftrace_ops *ops,
5509                                 struct dentry *parent)
5510 {
5511 
5512         trace_create_file("set_ftrace_filter", 0644, parent,
5513                           ops, &ftrace_filter_fops);
5514 
5515         trace_create_file("set_ftrace_notrace", 0644, parent,
5516                           ops, &ftrace_notrace_fops);
5517 }
5518 
5519 /*
5520  * The name "destroy_filter_files" is really a misnomer. Although
5521  * in the future, it may actually delete the files, but this is
5522  * really intended to make sure the ops passed in are disabled
5523  * and that when this function returns, the caller is free to
5524  * free the ops.
5525  *
5526  * The "destroy" name is only to match the "create" name that this
5527  * should be paired with.
5528  */
5529 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5530 {
5531         mutex_lock(&ftrace_lock);
5532         if (ops->flags & FTRACE_OPS_FL_ENABLED)
5533                 ftrace_shutdown(ops, 0);
5534         ops->flags |= FTRACE_OPS_FL_DELETED;
5535         ftrace_free_filter(ops);
5536         mutex_unlock(&ftrace_lock);
5537 }
5538 
5539 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5540 {
5541 
5542         trace_create_file("available_filter_functions", 0444,
5543                         d_tracer, NULL, &ftrace_avail_fops);
5544 
5545         trace_create_file("enabled_functions", 0444,
5546                         d_tracer, NULL, &ftrace_enabled_fops);
5547 
5548         ftrace_create_filter_files(&global_ops, d_tracer);
5549 
5550 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5551         trace_create_file("set_graph_function", 0644, d_tracer,
5552                                     NULL,
5553                                     &ftrace_graph_fops);
5554         trace_create_file("set_graph_notrace", 0644, d_tracer,
5555                                     NULL,
5556                                     &ftrace_graph_notrace_fops);
5557 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5558 
5559         return 0;
5560 }
5561 
5562 static int ftrace_cmp_ips(const void *a, const void *b)
5563 {
5564         const unsigned long *ipa = a;
5565         const unsigned long *ipb = b;
5566 
5567         if (*ipa > *ipb)
5568                 return 1;
5569         if (*ipa < *ipb)
5570                 return -1;
5571         return 0;
5572 }
5573 
5574 static int ftrace_process_locs(struct module *mod,
5575                                unsigned long *start,
5576                                unsigned long *end)
5577 {
5578         struct ftrace_page *start_pg;
5579         struct ftrace_page *pg;
5580         struct dyn_ftrace *rec;
5581         unsigned long count;
5582         unsigned long *p;
5583         unsigned long addr;
5584         unsigned long flags = 0; /* Shut up gcc */
5585         int ret = -ENOMEM;
5586 
5587         count = end - start;
5588 
5589         if (!count)
5590                 return 0;
5591 
5592         sort(start, count, sizeof(*start),
5593              ftrace_cmp_ips, NULL);
5594 
5595         start_pg = ftrace_allocate_pages(count);
5596         if (!start_pg)
5597                 return -ENOMEM;
5598 
5599         mutex_lock(&ftrace_lock);
5600 
5601         /*
5602          * Core and each module needs their own pages, as
5603          * modules will free them when they are removed.
5604          * Force a new page to be allocated for modules.
5605          */
5606         if (!mod) {
5607                 WARN_ON(ftrace_pages || ftrace_pages_start);
5608                 /* First initialization */
5609                 ftrace_pages = ftrace_pages_start = start_pg;
5610         } else {
5611                 if (!ftrace_pages)
5612                         goto out;
5613 
5614                 if (WARN_ON(ftrace_pages->next)) {
5615                         /* Hmm, we have free pages? */
5616                         while (ftrace_pages->next)
5617                                 ftrace_pages = ftrace_pages->next;
5618                 }
5619 
5620                 ftrace_pages->next = start_pg;
5621         }
5622 
5623         p = start;
5624         pg = start_pg;
5625         while (p < end) {
5626                 addr = ftrace_call_adjust(*p++);
5627                 /*
5628                  * Some architecture linkers will pad between
5629                  * the different mcount_loc sections of different
5630                  * object files to satisfy alignments.
5631                  * Skip any NULL pointers.
5632                  */
5633                 if (!addr)
5634                         continue;
5635 
5636                 if (pg->index == pg->size) {
5637                         /* We should have allocated enough */
5638                         if (WARN_ON(!pg->next))
5639                                 break;
5640                         pg = pg->next;
5641                 }
5642 
5643                 rec = &pg->records[pg->index++];
5644                 rec->ip = addr;
5645         }
5646 
5647         /* We should have used all pages */
5648         WARN_ON(pg->next);
5649 
5650         /* Assign the last page to ftrace_pages */
5651         ftrace_pages = pg;
5652 
5653         /*
5654          * We only need to disable interrupts on start up
5655          * because we are modifying code that an interrupt
5656          * may execute, and the modification is not atomic.
5657          * But for modules, nothing runs the code we modify
5658          * until we are finished with it, and there's no
5659          * reason to cause large interrupt latencies while we do it.
5660          */
5661         if (!mod)
5662                 local_irq_save(flags);
5663         ftrace_update_code(mod, start_pg);
5664         if (!mod)
5665                 local_irq_restore(flags);
5666         ret = 0;
5667  out:
5668         mutex_unlock(&ftrace_lock);
5669 
5670         return ret;
5671 }
5672 
5673 struct ftrace_mod_func {
5674         struct list_head        list;
5675         char                    *name;
5676         unsigned long           ip;
5677         unsigned int            size;
5678 };
5679 
5680 struct ftrace_mod_map {
5681         struct rcu_head         rcu;
5682         struct list_head        list;
5683         struct module           *mod;
5684         unsigned long           start_addr;
5685         unsigned long           end_addr;
5686         struct list_head        funcs;
5687         unsigned int            num_funcs;
5688 };
5689 
5690 #ifdef CONFIG_MODULES
5691 
5692 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5693 
5694 static LIST_HEAD(ftrace_mod_maps);
5695 
5696 static int referenced_filters(struct dyn_ftrace *rec)
5697 {
5698         struct ftrace_ops *ops;
5699         int cnt = 0;
5700 
5701         for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5702                 if (ops_references_rec(ops, rec))
5703                     cnt++;
5704         }
5705 
5706         return cnt;
5707 }
5708 
5709 static void
5710 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5711 {
5712         struct ftrace_func_entry *entry;
5713         struct dyn_ftrace *rec;
5714         int i;
5715 
5716         if (ftrace_hash_empty(hash))
5717                 return;
5718 
5719         for (i = 0; i < pg->index; i++) {
5720                 rec = &pg->records[i];
5721                 entry = __ftrace_lookup_ip(hash, rec->ip);
5722                 /*
5723                  * Do not allow this rec to match again.
5724                  * Yeah, it may waste some memory, but will be removed
5725                  * if/when the hash is modified again.
5726                  */
5727                 if (entry)
5728                         entry->ip = 0;
5729         }
5730 }
5731 
5732 /* Clear any records from hashs */
5733 static void clear_mod_from_hashes(struct ftrace_page *pg)
5734 {
5735         struct trace_array *tr;
5736 
5737         mutex_lock(&trace_types_lock);
5738         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5739                 if (!tr->ops || !tr->ops->func_hash)
5740                         continue;
5741                 mutex_lock(&tr->ops->func_hash->regex_lock);
5742                 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5743                 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5744                 mutex_unlock(&tr->ops->func_hash->regex_lock);
5745         }
5746         mutex_unlock(&trace_types_lock);
5747 }
5748 
5749 static void ftrace_free_mod_map(struct rcu_head *rcu)
5750 {
5751         struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
5752         struct ftrace_mod_func *mod_func;
5753         struct ftrace_mod_func *n;
5754 
5755         /* All the contents of mod_map are now not visible to readers */
5756         list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
5757                 kfree(mod_func->name);
5758                 list_del(&mod_func->list);
5759                 kfree(mod_func);
5760         }
5761 
5762         kfree(mod_map);
5763 }
5764 
5765 void ftrace_release_mod(struct module *mod)
5766 {
5767         struct ftrace_mod_map *mod_map;
5768         struct ftrace_mod_map *n;
5769         struct dyn_ftrace *rec;
5770         struct ftrace_page **last_pg;
5771         struct ftrace_page *tmp_page = NULL;
5772         struct ftrace_page *pg;
5773         int order;
5774 
5775         mutex_lock(&ftrace_lock);
5776 
5777         if (ftrace_disabled)
5778                 goto out_unlock;
5779 
5780         list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
5781                 if (mod_map->mod == mod) {
5782                         list_del_rcu(&mod_map->list);
5783                         call_rcu(&mod_map->rcu, ftrace_free_mod_map);
5784                         break;
5785                 }
5786         }
5787 
5788         /*
5789          * Each module has its own ftrace_pages, remove
5790          * them from the list.
5791          */
5792         last_pg = &ftrace_pages_start;
5793         for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5794                 rec = &pg->records[0];
5795                 if (within_module_core(rec->ip, mod) ||
5796                     within_module_init(rec->ip, mod)) {
5797                         /*
5798                          * As core pages are first, the first
5799                          * page should never be a module page.
5800                          */
5801                         if (WARN_ON(pg == ftrace_pages_start))
5802                                 goto out_unlock;
5803 
5804                         /* Check if we are deleting the last page */
5805                         if (pg == ftrace_pages)
5806                                 ftrace_pages = next_to_ftrace_page(last_pg);
5807 
5808                         ftrace_update_tot_cnt -= pg->index;
5809                         *last_pg = pg->next;
5810 
5811                         pg->next = tmp_page;
5812                         tmp_page = pg;
5813                 } else
5814                         last_pg = &pg->next;
5815         }
5816  out_unlock:
5817         mutex_unlock(&ftrace_lock);
5818 
5819         for (pg = tmp_page; pg; pg = tmp_page) {
5820 
5821                 /* Needs to be called outside of ftrace_lock */
5822                 clear_mod_from_hashes(pg);
5823 
5824                 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5825                 free_pages((unsigned long)pg->records, order);
5826                 tmp_page = pg->next;
5827                 kfree(pg);
5828         }
5829 }
5830 
5831 void ftrace_module_enable(struct module *mod)
5832 {
5833         struct dyn_ftrace *rec;
5834         struct ftrace_page *pg;
5835 
5836         mutex_lock(&ftrace_lock);
5837 
5838         if (ftrace_disabled)
5839                 goto out_unlock;
5840 
5841         /*
5842          * If the tracing is enabled, go ahead and enable the record.
5843          *
5844          * The reason not to enable the record immediately is the
5845          * inherent check of ftrace_make_nop/ftrace_make_call for
5846          * correct previous instructions.  Making first the NOP
5847          * conversion puts the module to the correct state, thus
5848          * passing the ftrace_make_call check.
5849          *
5850          * We also delay this to after the module code already set the
5851          * text to read-only, as we now need to set it back to read-write
5852          * so that we can modify the text.
5853          */
5854         if (ftrace_start_up)
5855                 ftrace_arch_code_modify_prepare();
5856 
5857         do_for_each_ftrace_rec(pg, rec) {
5858                 int cnt;
5859                 /*
5860                  * do_for_each_ftrace_rec() is a double loop.
5861                  * module text shares the pg. If a record is
5862                  * not part of this module, then skip this pg,
5863                  * which the "break" will do.
5864                  */
5865                 if (!within_module_core(rec->ip, mod) &&
5866                     !within_module_init(rec->ip, mod))
5867                         break;
5868 
5869                 cnt = 0;
5870 
5871                 /*
5872                  * When adding a module, we need to check if tracers are
5873                  * currently enabled and if they are, and can trace this record,
5874                  * we need to enable the module functions as well as update the
5875                  * reference counts for those function records.
5876                  */
5877                 if (ftrace_start_up)
5878                         cnt += referenced_filters(rec);
5879 
5880                 /* This clears FTRACE_FL_DISABLED */
5881                 rec->flags = cnt;
5882 
5883                 if (ftrace_start_up && cnt) {
5884                         int failed = __ftrace_replace_code(rec, 1);
5885                         if (failed) {
5886                                 ftrace_bug(failed, rec);
5887                                 goto out_loop;
5888                         }
5889                 }
5890 
5891         } while_for_each_ftrace_rec();
5892 
5893  out_loop:
5894         if (ftrace_start_up)
5895                 ftrace_arch_code_modify_post_process();
5896 
5897  out_unlock:
5898         mutex_unlock(&ftrace_lock);
5899 
5900         process_cached_mods(mod->name);
5901 }
5902 
5903 void ftrace_module_init(struct module *mod)
5904 {
5905         if (ftrace_disabled || !mod->num_ftrace_callsites)
5906                 return;
5907 
5908         ftrace_process_locs(mod, mod->ftrace_callsites,
5909                             mod->ftrace_callsites + mod->num_ftrace_callsites);
5910 }
5911 
5912 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
5913                                 struct dyn_ftrace *rec)
5914 {
5915         struct ftrace_mod_func *mod_func;
5916         unsigned long symsize;
5917         unsigned long offset;
5918         char str[KSYM_SYMBOL_LEN];
5919         char *modname;
5920         const char *ret;
5921 
5922         ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
5923         if (!ret)
5924                 return;
5925 
5926         mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
5927         if (!mod_func)
5928                 return;
5929 
5930         mod_func->name = kstrdup(str, GFP_KERNEL);
5931         if (!mod_func->name) {
5932                 kfree(mod_func);
5933                 return;
5934         }
5935 
5936         mod_func->ip = rec->ip - offset;
5937         mod_func->size = symsize;
5938 
5939         mod_map->num_funcs++;
5940 
5941         list_add_rcu(&mod_func->list, &mod_map->funcs);
5942 }
5943 
5944 static struct ftrace_mod_map *
5945 allocate_ftrace_mod_map(struct module *mod,
5946                         unsigned long start, unsigned long end)
5947 {
5948         struct ftrace_mod_map *mod_map;
5949 
5950         mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
5951         if (!mod_map)
5952                 return NULL;
5953 
5954         mod_map->mod = mod;
5955         mod_map->start_addr = start;
5956         mod_map->end_addr = end;
5957         mod_map->num_funcs = 0;
5958 
5959         INIT_LIST_HEAD_RCU(&mod_map->funcs);
5960 
5961         list_add_rcu(&mod_map->list, &ftrace_mod_maps);
5962 
5963         return mod_map;
5964 }
5965 
5966 static const char *
5967 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
5968                            unsigned long addr, unsigned long *size,
5969                            unsigned long *off, char *sym)
5970 {
5971         struct ftrace_mod_func *found_func =  NULL;
5972         struct ftrace_mod_func *mod_func;
5973 
5974         list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
5975                 if (addr >= mod_func->ip &&
5976                     addr < mod_func->ip + mod_func->size) {
5977                         found_func = mod_func;
5978                         break;
5979                 }
5980         }
5981 
5982         if (found_func) {
5983                 if (size)
5984                         *size = found_func->size;
5985                 if (off)
5986                         *off = addr - found_func->ip;
5987                 if (sym)
5988                         strlcpy(sym, found_func->name, KSYM_NAME_LEN);
5989 
5990                 return found_func->name;
5991         }
5992 
5993         return NULL;
5994 }
5995 
5996 const char *
5997 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
5998                    unsigned long *off, char **modname, char *sym)
5999 {
6000         struct ftrace_mod_map *mod_map;
6001         const char *ret = NULL;
6002 
6003         /* mod_map is freed via call_rcu() */
6004         preempt_disable();
6005         list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6006                 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6007                 if (ret) {
6008                         if (modname)
6009                                 *modname = mod_map->mod->name;
6010                         break;
6011                 }
6012         }
6013         preempt_enable();
6014 
6015         return ret;
6016 }
6017 
6018 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6019                            char *type, char *name,
6020                            char *module_name, int *exported)
6021 {
6022         struct ftrace_mod_map *mod_map;
6023         struct ftrace_mod_func *mod_func;
6024 
6025         preempt_disable();
6026         list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6027 
6028                 if (symnum >= mod_map->num_funcs) {
6029                         symnum -= mod_map->num_funcs;
6030                         continue;
6031                 }
6032 
6033                 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6034                         if (symnum > 1) {
6035                                 symnum--;
6036                                 continue;
6037                         }
6038 
6039                         *value = mod_func->ip;
6040                         *type = 'T';
6041                         strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6042                         strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6043                         *exported = 1;
6044                         preempt_enable();
6045                         return 0;
6046                 }
6047                 WARN_ON(1);
6048                 break;
6049         }
6050         preempt_enable();
6051         return -ERANGE;
6052 }
6053 
6054 #else
6055 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6056                                 struct dyn_ftrace *rec) { }
6057 static inline struct ftrace_mod_map *
6058 allocate_ftrace_mod_map(struct module *mod,
6059                         unsigned long start, unsigned long end)
6060 {
6061         return NULL;
6062 }
6063 #endif /* CONFIG_MODULES */
6064 
6065 struct ftrace_init_func {
6066         struct list_head list;
6067         unsigned long ip;
6068 };
6069 
6070 /* Clear any init ips from hashes */
6071 static void
6072 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6073 {
6074         struct ftrace_func_entry *entry;
6075 
6076         entry = ftrace_lookup_ip(hash, func->ip);
6077         /*
6078          * Do not allow this rec to match again.
6079          * Yeah, it may waste some memory, but will be removed
6080          * if/when the hash is modified again.
6081          */
6082         if (entry)
6083                 entry->ip = 0;
6084 }
6085 
6086 static void
6087 clear_func_from_hashes(struct ftrace_init_func *func)
6088 {
6089         struct trace_array *tr;
6090 
6091         mutex_lock(&trace_types_lock);
6092         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6093                 if (!tr->ops || !tr->ops->func_hash)
6094                         continue;
6095                 mutex_lock(&tr->ops->func_hash->regex_lock);
6096                 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6097                 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6098                 mutex_unlock(&tr->ops->func_hash->regex_lock);
6099         }
6100         mutex_unlock(&trace_types_lock);
6101 }
6102 
6103 static void add_to_clear_hash_list(struct list_head *clear_list,
6104                                    struct dyn_ftrace *rec)
6105 {
6106         struct ftrace_init_func *func;
6107 
6108         func = kmalloc(sizeof(*func), GFP_KERNEL);
6109         if (!func) {
6110                 WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n");
6111                 return;
6112         }
6113 
6114         func->ip = rec->ip;
6115         list_add(&func->list, clear_list);
6116 }
6117 
6118 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6119 {
6120         unsigned long start = (unsigned long)(start_ptr);
6121         unsigned long end = (unsigned long)(end_ptr);
6122         struct ftrace_page **last_pg = &ftrace_pages_start;
6123         struct ftrace_page *pg;
6124         struct dyn_ftrace *rec;
6125         struct dyn_ftrace key;
6126         struct ftrace_mod_map *mod_map = NULL;
6127         struct ftrace_init_func *func, *func_next;
6128         struct list_head clear_hash;
6129         int order;
6130 
6131         INIT_LIST_HEAD(&clear_hash);
6132 
6133         key.ip = start;
6134         key.flags = end;        /* overload flags, as it is unsigned long */
6135 
6136         mutex_lock(&ftrace_lock);
6137 
6138         /*
6139          * If we are freeing module init memory, then check if
6140          * any tracer is active. If so, we need to save a mapping of
6141          * the module functions being freed with the address.
6142          */
6143         if (mod && ftrace_ops_list != &ftrace_list_end)
6144                 mod_map = allocate_ftrace_mod_map(mod, start, end);
6145 
6146         for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6147                 if (end < pg->records[0].ip ||
6148                     start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6149                         continue;
6150  again:
6151                 rec = bsearch(&key, pg->records, pg->index,
6152                               sizeof(struct dyn_ftrace),
6153                               ftrace_cmp_recs);
6154                 if (!rec)
6155                         continue;
6156 
6157                 /* rec will be cleared from hashes after ftrace_lock unlock */
6158                 add_to_clear_hash_list(&clear_hash, rec);
6159 
6160                 if (mod_map)
6161                         save_ftrace_mod_rec(mod_map, rec);
6162 
6163                 pg->index--;
6164                 ftrace_update_tot_cnt--;
6165                 if (!pg->index) {
6166                         *last_pg = pg->next;
6167                         order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6168                         free_pages((unsigned long)pg->records, order);
6169                         kfree(pg);
6170                         pg = container_of(last_pg, struct ftrace_page, next);
6171                         if (!(*last_pg))
6172                                 ftrace_pages = pg;
6173                         continue;
6174                 }
6175                 memmove(rec, rec + 1,
6176                         (pg->index - (rec - pg->records)) * sizeof(*rec));
6177                 /* More than one function may be in this block */
6178                 goto again;
6179         }
6180         mutex_unlock(&ftrace_lock);
6181 
6182         list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6183                 clear_func_from_hashes(func);
6184                 kfree(func);
6185         }
6186 }
6187 
6188 void __init ftrace_free_init_mem(void)
6189 {
6190         void *start = (void *)(&__init_begin);
6191         void *end = (void *)(&__init_end);
6192 
6193         ftrace_free_mem(NULL, start, end);
6194 }
6195 
6196 void __init ftrace_init(void)
6197 {
6198         extern unsigned long __start_mcount_loc[];
6199         extern unsigned long __stop_mcount_loc[];
6200         unsigned long count, flags;
6201         int ret;
6202 
6203         local_irq_save(flags);
6204         ret = ftrace_dyn_arch_init();
6205         local_irq_restore(flags);
6206         if (ret)
6207                 goto failed;
6208 
6209         count = __stop_mcount_loc - __start_mcount_loc;
6210         if (!count) {
6211                 pr_info("ftrace: No functions to be traced?\n");
6212                 goto failed;
6213         }
6214 
6215         pr_info("ftrace: allocating %ld entries in %ld pages\n",
6216                 count, count / ENTRIES_PER_PAGE + 1);
6217 
6218         last_ftrace_enabled = ftrace_enabled = 1;
6219 
6220         ret = ftrace_process_locs(NULL,
6221                                   __start_mcount_loc,
6222                                   __stop_mcount_loc);
6223 
6224         set_ftrace_early_filters();
6225 
6226         return;
6227  failed:
6228         ftrace_disabled = 1;
6229 }
6230 
6231 /* Do nothing if arch does not support this */
6232 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6233 {
6234 }
6235 
6236 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6237 {
6238         arch_ftrace_update_trampoline(ops);
6239 }
6240 
6241 void ftrace_init_trace_array(struct trace_array *tr)
6242 {
6243         INIT_LIST_HEAD(&tr->func_probes);
6244         INIT_LIST_HEAD(&tr->mod_trace);
6245         INIT_LIST_HEAD(&tr->mod_notrace);
6246 }
6247 #else
6248 
6249 struct ftrace_ops global_ops = {
6250         .func                   = ftrace_stub,
6251         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE |
6252                                   FTRACE_OPS_FL_INITIALIZED |
6253                                   FTRACE_OPS_FL_PID,
6254 };
6255 
6256 static int __init ftrace_nodyn_init(void)
6257 {
6258         ftrace_enabled = 1;
6259         return 0;
6260 }
6261 core_initcall(ftrace_nodyn_init);
6262 
6263 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6264 static inline void ftrace_startup_enable(int command) { }
6265 static inline void ftrace_startup_all(int command) { }
6266 
6267 # define ftrace_startup_sysctl()        do { } while (0)
6268 # define ftrace_shutdown_sysctl()       do { } while (0)
6269 
6270 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6271 {
6272 }
6273 
6274 #endif /* CONFIG_DYNAMIC_FTRACE */
6275 
6276 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6277 {
6278         tr->ops = &global_ops;
6279         tr->ops->private = tr;
6280         ftrace_init_trace_array(tr);
6281 }
6282 
6283 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6284 {
6285         /* If we filter on pids, update to use the pid function */
6286         if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6287                 if (WARN_ON(tr->ops->func != ftrace_stub))
6288                         printk("ftrace ops had %pS for function\n",
6289                                tr->ops->func);
6290         }
6291         tr->ops->func = func;
6292         tr->ops->private = tr;
6293 }
6294 
6295 void ftrace_reset_array_ops(struct trace_array *tr)
6296 {
6297         tr->ops->func = ftrace_stub;
6298 }
6299 
6300 static nokprobe_inline void
6301 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6302                        struct ftrace_ops *ignored, struct pt_regs *regs)
6303 {
6304         struct ftrace_ops *op;
6305         int bit;
6306 
6307         bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6308         if (bit < 0)
6309                 return;
6310 
6311         /*
6312          * Some of the ops may be dynamically allocated,
6313          * they must be freed after a synchronize_rcu().
6314          */
6315         preempt_disable_notrace();
6316 
6317         do_for_each_ftrace_op(op, ftrace_ops_list) {
6318                 /* Stub functions don't need to be called nor tested */
6319                 if (op->flags & FTRACE_OPS_FL_STUB)
6320                         continue;
6321                 /*
6322                  * Check the following for each ops before calling their func:
6323                  *  if RCU flag is set, then rcu_is_watching() must be true
6324                  *  if PER_CPU is set, then ftrace_function_local_disable()
6325                  *                          must be false
6326                  *  Otherwise test if the ip matches the ops filter
6327                  *
6328                  * If any of the above fails then the op->func() is not executed.
6329                  */
6330                 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6331                     ftrace_ops_test(op, ip, regs)) {
6332                         if (FTRACE_WARN_ON(!op->func)) {
6333                                 pr_warn("op=%p %pS\n", op, op);
6334                                 goto out;
6335                         }
6336                         op->func(ip, parent_ip, op, regs);
6337                 }
6338         } while_for_each_ftrace_op(op);
6339 out:
6340         preempt_enable_notrace();
6341         trace_clear_recursion(bit);
6342 }
6343 
6344 /*
6345  * Some archs only support passing ip and parent_ip. Even though
6346  * the list function ignores the op parameter, we do not want any
6347  * C side effects, where a function is called without the caller
6348  * sending a third parameter.
6349  * Archs are to support both the regs and ftrace_ops at the same time.
6350  * If they support ftrace_ops, it is assumed they support regs.
6351  * If call backs want to use regs, they must either check for regs
6352  * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6353  * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6354  * An architecture can pass partial regs with ftrace_ops and still
6355  * set the ARCH_SUPPORTS_FTRACE_OPS.
6356  */
6357 #if ARCH_SUPPORTS_FTRACE_OPS
6358 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6359                                  struct ftrace_ops *op, struct pt_regs *regs)
6360 {
6361         __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6362 }
6363 NOKPROBE_SYMBOL(ftrace_ops_list_func);
6364 #else
6365 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6366 {
6367         __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6368 }
6369 NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6370 #endif
6371 
6372 /*
6373  * If there's only one function registered but it does not support
6374  * recursion, needs RCU protection and/or requires per cpu handling, then
6375  * this function will be called by the mcount trampoline.
6376  */
6377 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6378                                    struct ftrace_ops *op, struct pt_regs *regs)
6379 {
6380         int bit;
6381 
6382         if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6383                 return;
6384 
6385         bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6386         if (bit < 0)
6387                 return;
6388 
6389         preempt_disable_notrace();
6390 
6391         op->func(ip, parent_ip, op, regs);
6392 
6393         preempt_enable_notrace();
6394         trace_clear_recursion(bit);
6395 }
6396 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
6397 
6398 /**
6399  * ftrace_ops_get_func - get the function a trampoline should call
6400  * @ops: the ops to get the function for
6401  *
6402  * Normally the mcount trampoline will call the ops->func, but there
6403  * are times that it should not. For example, if the ops does not
6404  * have its own recursion protection, then it should call the
6405  * ftrace_ops_assist_func() instead.
6406  *
6407  * Returns the function that the trampoline should call for @ops.
6408  */
6409 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6410 {
6411         /*
6412          * If the function does not handle recursion, needs to be RCU safe,
6413          * or does per cpu logic, then we need to call the assist handler.
6414          */
6415         if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6416             ops->flags & FTRACE_OPS_FL_RCU)
6417                 return ftrace_ops_assist_func;
6418 
6419         return ops->func;
6420 }
6421 
6422 static void
6423 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6424                     struct task_struct *prev, struct task_struct *next)
6425 {
6426         struct trace_array *tr = data;
6427         struct trace_pid_list *pid_list;
6428 
6429         pid_list = rcu_dereference_sched(tr->function_pids);
6430 
6431         this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6432                        trace_ignore_this_task(pid_list, next));
6433 }
6434 
6435 static void
6436 ftrace_pid_follow_sched_process_fork(void *data,
6437                                      struct task_struct *self,
6438                                      struct task_struct *task)
6439 {
6440         struct trace_pid_list *pid_list;
6441         struct trace_array *tr = data;
6442 
6443         pid_list = rcu_dereference_sched(tr->function_pids);
6444         trace_filter_add_remove_task(pid_list, self, task);
6445 }
6446 
6447 static void
6448 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6449 {
6450         struct trace_pid_list *pid_list;
6451         struct trace_array *tr = data;
6452 
6453         pid_list = rcu_dereference_sched(tr->function_pids);
6454         trace_filter_add_remove_task(pid_list, NULL, task);
6455 }
6456 
6457 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6458 {
6459         if (enable) {
6460                 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6461                                                   tr);
6462                 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6463                                                   tr);
6464         } else {
6465                 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6466                                                     tr);
6467                 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6468                                                     tr);
6469         }
6470 }
6471 
6472 static void clear_ftrace_pids(struct trace_array *tr)
6473 {
6474         struct trace_pid_list *pid_list;
6475         int cpu;
6476 
6477         pid_list = rcu_dereference_protected(tr->function_pids,
6478                                              lockdep_is_held(&ftrace_lock));
6479         if (!pid_list)
6480                 return;
6481 
6482         unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6483 
6484         for_each_possible_cpu(cpu)
6485                 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6486 
6487         rcu_assign_pointer(tr->function_pids, NULL);
6488 
6489         /* Wait till all users are no longer using pid filtering */
6490         synchronize_rcu();
6491 
6492         trace_free_pid_list(pid_list);
6493 }
6494 
6495 void ftrace_clear_pids(struct trace_array *tr)
6496 {
6497         mutex_lock(&ftrace_lock);
6498 
6499         clear_ftrace_pids(tr);
6500 
6501         mutex_unlock(&ftrace_lock);
6502 }
6503 
6504 static void ftrace_pid_reset(struct trace_array *tr)
6505 {
6506         mutex_lock(&ftrace_lock);
6507         clear_ftrace_pids(tr);
6508 
6509         ftrace_update_pid_func();
6510         ftrace_startup_all(0);
6511 
6512         mutex_unlock(&ftrace_lock);
6513 }
6514 
6515 /* Greater than any max PID */
6516 #define FTRACE_NO_PIDS          (void *)(PID_MAX_LIMIT + 1)
6517 
6518 static void *fpid_start(struct seq_file *m, loff_t *pos)
6519         __acquires(RCU)
6520 {
6521         struct trace_pid_list *pid_list;
6522         struct trace_array *tr = m->private;
6523 
6524         mutex_lock(&ftrace_lock);
6525         rcu_read_lock_sched();
6526 
6527         pid_list = rcu_dereference_sched(tr->function_pids);
6528 
6529         if (!pid_list)
6530                 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6531 
6532         return trace_pid_start(pid_list, pos);
6533 }
6534 
6535 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6536 {
6537         struct trace_array *tr = m->private;
6538         struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6539 
6540         if (v == FTRACE_NO_PIDS) {
6541                 (*pos)++;
6542                 return NULL;
6543         }
6544         return trace_pid_next(pid_list, v, pos);
6545 }
6546 
6547 static void fpid_stop(struct seq_file *m, void *p)
6548         __releases(RCU)
6549 {
6550         rcu_read_unlock_sched();
6551         mutex_unlock(&ftrace_lock);
6552 }
6553 
6554 static int fpid_show(struct seq_file *m, void *v)
6555 {
6556         if (v == FTRACE_NO_PIDS) {
6557                 seq_puts(m, "no pid\n");
6558                 return 0;
6559         }
6560 
6561         return trace_pid_show(m, v);
6562 }
6563 
6564 static const struct seq_operations ftrace_pid_sops = {
6565         .start = fpid_start,
6566         .next = fpid_next,
6567         .stop = fpid_stop,
6568         .show = fpid_show,
6569 };
6570 
6571 static int
6572 ftrace_pid_open(struct inode *inode, struct file *file)
6573 {
6574         struct trace_array *tr = inode->i_private;
6575         struct seq_file *m;
6576         int ret = 0;
6577 
6578         ret = tracing_check_open_get_tr(tr);
6579         if (ret)
6580                 return ret;
6581 
6582         if ((file->f_mode & FMODE_WRITE) &&
6583             (file->f_flags & O_TRUNC))
6584                 ftrace_pid_reset(tr);
6585 
6586         ret = seq_open(file, &ftrace_pid_sops);
6587         if (ret < 0) {
6588                 trace_array_put(tr);
6589         } else {
6590                 m = file->private_data;
6591                 /* copy tr over to seq ops */
6592                 m->private = tr;
6593         }
6594 
6595         return ret;
6596 }
6597 
6598 static void ignore_task_cpu(void *data)
6599 {
6600         struct trace_array *tr = data;
6601         struct trace_pid_list *pid_list;
6602 
6603         /*
6604          * This function is called by on_each_cpu() while the
6605          * event_mutex is held.
6606          */
6607         pid_list = rcu_dereference_protected(tr->function_pids,
6608                                              mutex_is_locked(&ftrace_lock));
6609 
6610         this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6611                        trace_ignore_this_task(pid_list, current));
6612 }
6613 
6614 static ssize_t
6615 ftrace_pid_write(struct file *filp, const char __user *ubuf,
6616                    size_t cnt, loff_t *ppos)
6617 {
6618         struct seq_file *m = filp->private_data;
6619         struct trace_array *tr = m->private;
6620         struct trace_pid_list *filtered_pids = NULL;
6621         struct trace_pid_list *pid_list;
6622         ssize_t ret;
6623 
6624         if (!cnt)
6625                 return 0;
6626 
6627         mutex_lock(&ftrace_lock);
6628 
6629         filtered_pids = rcu_dereference_protected(tr->function_pids,
6630                                              lockdep_is_held(&ftrace_lock));
6631 
6632         ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6633         if (ret < 0)
6634                 goto out;
6635 
6636         rcu_assign_pointer(tr->function_pids, pid_list);
6637 
6638         if (filtered_pids) {
6639                 synchronize_rcu();
6640                 trace_free_pid_list(filtered_pids);
6641         } else if (pid_list) {
6642                 /* Register a probe to set whether to ignore the tracing of a task */
6643                 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6644         }
6645 
6646         /*
6647          * Ignoring of pids is done at task switch. But we have to
6648          * check for those tasks that are currently running.
6649          * Always do this in case a pid was appended or removed.
6650          */
6651         on_each_cpu(ignore_task_cpu, tr, 1);
6652 
6653         ftrace_update_pid_func();
6654         ftrace_startup_all(0);
6655  out:
6656         mutex_unlock(&ftrace_lock);
6657 
6658         if (ret > 0)
6659                 *ppos += ret;
6660 
6661         return ret;
6662 }
6663 
6664 static int
6665 ftrace_pid_release(struct inode *inode, struct file *file)
6666 {
6667         struct trace_array *tr = inode->i_private;
6668 
6669         trace_array_put(tr);
6670 
6671         return seq_release(inode, file);
6672 }
6673 
6674 static const struct file_operations ftrace_pid_fops = {
6675         .open           = ftrace_pid_open,
6676         .write          = ftrace_pid_write,
6677         .read           = seq_read,
6678         .llseek         = tracing_lseek,
6679         .release        = ftrace_pid_release,
6680 };
6681 
6682 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6683 {
6684         trace_create_file("set_ftrace_pid", 0644, d_tracer,
6685                             tr, &ftrace_pid_fops);
6686 }
6687 
6688 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6689                                          struct dentry *d_tracer)
6690 {
6691         /* Only the top level directory has the dyn_tracefs and profile */
6692         WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6693 
6694         ftrace_init_dyn_tracefs(d_tracer);
6695         ftrace_profile_tracefs(d_tracer);
6696 }
6697 
6698 /**
6699  * ftrace_kill - kill ftrace
6700  *
6701  * This function should be used by panic code. It stops ftrace
6702  * but in a not so nice way. If you need to simply kill ftrace
6703  * from a non-atomic section, use ftrace_kill.
6704  */
6705 void ftrace_kill(void)
6706 {
6707         ftrace_disabled = 1;
6708         ftrace_enabled = 0;
6709         ftrace_trace_function = ftrace_stub;
6710 }
6711 
6712 /**
6713  * Test if ftrace is dead or not.
6714  */
6715 int ftrace_is_dead(void)
6716 {
6717         return ftrace_disabled;
6718 }
6719 
6720 /**
6721  * register_ftrace_function - register a function for profiling
6722  * @ops - ops structure that holds the function for profiling.
6723  *
6724  * Register a function to be called by all functions in the
6725  * kernel.
6726  *
6727  * Note: @ops->func and all the functions it calls must be labeled
6728  *       with "notrace", otherwise it will go into a
6729  *       recursive loop.
6730  */
6731 int register_ftrace_function(struct ftrace_ops *ops)
6732 {
6733         int ret = -1;
6734 
6735         ftrace_ops_init(ops);
6736 
6737         mutex_lock(&ftrace_lock);
6738 
6739         ret = ftrace_startup(ops, 0);
6740 
6741         mutex_unlock(&ftrace_lock);
6742 
6743         return ret;
6744 }
6745 EXPORT_SYMBOL_GPL(register_ftrace_function);
6746 
6747 /**
6748  * unregister_ftrace_function - unregister a function for profiling.
6749  * @ops - ops structure that holds the function to unregister
6750  *
6751  * Unregister a function that was added to be called by ftrace profiling.
6752  */
6753 int unregister_ftrace_function(struct ftrace_ops *ops)
6754 {
6755         int ret;
6756 
6757         mutex_lock(&ftrace_lock);
6758         ret = ftrace_shutdown(ops, 0);
6759         mutex_unlock(&ftrace_lock);
6760 
6761         return ret;
6762 }
6763 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6764 
6765 int
6766 ftrace_enable_sysctl(struct ctl_table *table, int write,
6767                      void __user *buffer, size_t *lenp,
6768                      loff_t *ppos)
6769 {
6770         int ret = -ENODEV;
6771 
6772         mutex_lock(&ftrace_lock);
6773 
6774         if (unlikely(ftrace_disabled))
6775                 goto out;
6776 
6777         ret = proc_dointvec(table, write, buffer, lenp, ppos);
6778 
6779         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6780                 goto out;
6781 
6782         last_ftrace_enabled = !!ftrace_enabled;
6783 
6784         if (ftrace_enabled) {
6785 
6786                 /* we are starting ftrace again */
6787                 if (rcu_dereference_protected(ftrace_ops_list,
6788                         lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
6789                         update_ftrace_function();
6790 
6791                 ftrace_startup_sysctl();
6792 
6793         } else {
6794                 /* stopping ftrace calls (just send to ftrace_stub) */
6795                 ftrace_trace_function = ftrace_stub;
6796 
6797                 ftrace_shutdown_sysctl();
6798         }
6799 
6800  out:
6801         mutex_unlock(&ftrace_lock);
6802         return ret;
6803 }