arch/x86/events/core.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
x86_perf_event_update
x86_pmu_extra_regs
reserve_pmc_hardware
release_pmc_hardware
reserve_pmc_hardware
release_pmc_hardware
check_hw_exists
hw_perf_event_destroy
hw_perf_lbr_event_destroy
x86_pmu_initialized
set_ext_hw_attr
x86_reserve_hardware
x86_release_hardware
x86_add_exclusive
x86_del_exclusive
x86_setup_perfctr
precise_br_compat
x86_pmu_max_precise
x86_pmu_hw_config
__x86_pmu_event_init
x86_pmu_disable_all
x86_pmu_disable
x86_pmu_enable_all
is_x86_event
x86_get_pmu
perf_sched_init
perf_sched_save_state
perf_sched_restore_state
__perf_sched_find_counter
perf_sched_find_counter
perf_sched_next_event
perf_assign_events
x86_schedule_events
collect_events
x86_assign_hw_event
x86_perf_rdpmc_index
match_prev_assignment
x86_pmu_enable
x86_perf_event_set_period
x86_pmu_enable_event
x86_pmu_add
x86_pmu_start
perf_event_print_debug
x86_pmu_stop
x86_pmu_del
x86_pmu_handle_irq
perf_events_lapic_init
perf_event_nmi_handler
x86_pmu_prepare_cpu
x86_pmu_dead_cpu
x86_pmu_online_cpu
x86_pmu_starting_cpu
x86_pmu_dying_cpu
pmu_check_apic
events_sysfs_show
events_ht_sysfs_show
is_visible
x86_event_sysfs_show
init_hw_perf_events
x86_pmu_read
x86_pmu_start_txn
x86_pmu_cancel_txn
x86_pmu_commit_txn
free_fake_cpuc
allocate_fake_cpuc
validate_event
validate_group
x86_pmu_event_init
refresh_pce
x86_pmu_event_mapped
x86_pmu_event_unmapped
x86_pmu_event_idx
get_attr_rdpmc
set_attr_rdpmc
max_precise_show
x86_pmu_sched_task
perf_check_microcode
x86_pmu_check_period
x86_pmu_aux_output_match
arch_perf_update_userpage
perf_hw_regs
perf_callchain_kernel
valid_user_frame
get_segment_base
perf_callchain_user32
perf_callchain_user32
perf_callchain_user
code_segment_base
perf_instruction_pointer
perf_misc_flags
perf_get_x86_pmu_capability
   1 /*
   2  * Performance events x86 architecture code
   3  *
   4  *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
   5  *  Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
   6  *  Copyright (C) 2009 Jaswinder Singh Rajput
   7  *  Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter
   8  *  Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra
   9  *  Copyright (C) 2009 Intel Corporation, <markus.t.metzger@intel.com>
  10  *  Copyright (C) 2009 Google, Inc., Stephane Eranian
  11  *
  12  *  For licencing details see kernel-base/COPYING
  13  */
  14 
  15 #include <linux/perf_event.h>
  16 #include <linux/capability.h>
  17 #include <linux/notifier.h>
  18 #include <linux/hardirq.h>
  19 #include <linux/kprobes.h>
  20 #include <linux/export.h>
  21 #include <linux/init.h>
  22 #include <linux/kdebug.h>
  23 #include <linux/sched/mm.h>
  24 #include <linux/sched/clock.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/slab.h>
  27 #include <linux/cpu.h>
  28 #include <linux/bitops.h>
  29 #include <linux/device.h>
  30 #include <linux/nospec.h>
  31 
  32 #include <asm/apic.h>
  33 #include <asm/stacktrace.h>
  34 #include <asm/nmi.h>
  35 #include <asm/smp.h>
  36 #include <asm/alternative.h>
  37 #include <asm/mmu_context.h>
  38 #include <asm/tlbflush.h>
  39 #include <asm/timer.h>
  40 #include <asm/desc.h>
  41 #include <asm/ldt.h>
  42 #include <asm/unwind.h>
  43 
  44 #include "perf_event.h"
  45 
  46 struct x86_pmu x86_pmu __read_mostly;
  47 
  48 DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
  49         .enabled = 1,
  50 };
  51 
  52 DEFINE_STATIC_KEY_FALSE(rdpmc_always_available_key);
  53 
  54 u64 __read_mostly hw_cache_event_ids
  55                                 [PERF_COUNT_HW_CACHE_MAX]
  56                                 [PERF_COUNT_HW_CACHE_OP_MAX]
  57                                 [PERF_COUNT_HW_CACHE_RESULT_MAX];
  58 u64 __read_mostly hw_cache_extra_regs
  59                                 [PERF_COUNT_HW_CACHE_MAX]
  60                                 [PERF_COUNT_HW_CACHE_OP_MAX]
  61                                 [PERF_COUNT_HW_CACHE_RESULT_MAX];
  62 
  63 /*
  64  * Propagate event elapsed time into the generic event.
  65  * Can only be executed on the CPU where the event is active.
  66  * Returns the delta events processed.
  67  */
  68 u64 x86_perf_event_update(struct perf_event *event)
  69 {
  70         struct hw_perf_event *hwc = &event->hw;
  71         int shift = 64 - x86_pmu.cntval_bits;
  72         u64 prev_raw_count, new_raw_count;
  73         int idx = hwc->idx;
  74         u64 delta;
  75 
  76         if (idx == INTEL_PMC_IDX_FIXED_BTS)
  77                 return 0;
  78 
  79         /*
  80          * Careful: an NMI might modify the previous event value.
  81          *
  82          * Our tactic to handle this is to first atomically read and
  83          * exchange a new raw count - then add that new-prev delta
  84          * count to the generic event atomically:
  85          */
  86 again:
  87         prev_raw_count = local64_read(&hwc->prev_count);
  88         rdpmcl(hwc->event_base_rdpmc, new_raw_count);
  89 
  90         if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
  91                                         new_raw_count) != prev_raw_count)
  92                 goto again;
  93 
  94         /*
  95          * Now we have the new raw value and have updated the prev
  96          * timestamp already. We can now calculate the elapsed delta
  97          * (event-)time and add that to the generic event.
  98          *
  99          * Careful, not all hw sign-extends above the physical width
 100          * of the count.
 101          */
 102         delta = (new_raw_count << shift) - (prev_raw_count << shift);
 103         delta >>= shift;
 104 
 105         local64_add(delta, &event->count);
 106         local64_sub(delta, &hwc->period_left);
 107 
 108         return new_raw_count;
 109 }
 110 
 111 /*
 112  * Find and validate any extra registers to set up.
 113  */
 114 static int x86_pmu_extra_regs(u64 config, struct perf_event *event)
 115 {
 116         struct hw_perf_event_extra *reg;
 117         struct extra_reg *er;
 118 
 119         reg = &event->hw.extra_reg;
 120 
 121         if (!x86_pmu.extra_regs)
 122                 return 0;
 123 
 124         for (er = x86_pmu.extra_regs; er->msr; er++) {
 125                 if (er->event != (config & er->config_mask))
 126                         continue;
 127                 if (event->attr.config1 & ~er->valid_mask)
 128                         return -EINVAL;
 129                 /* Check if the extra msrs can be safely accessed*/
 130                 if (!er->extra_msr_access)
 131                         return -ENXIO;
 132 
 133                 reg->idx = er->idx;
 134                 reg->config = event->attr.config1;
 135                 reg->reg = er->msr;
 136                 break;
 137         }
 138         return 0;
 139 }
 140 
 141 static atomic_t active_events;
 142 static atomic_t pmc_refcount;
 143 static DEFINE_MUTEX(pmc_reserve_mutex);
 144 
 145 #ifdef CONFIG_X86_LOCAL_APIC
 146 
 147 static bool reserve_pmc_hardware(void)
 148 {
 149         int i;
 150 
 151         for (i = 0; i < x86_pmu.num_counters; i++) {
 152                 if (!reserve_perfctr_nmi(x86_pmu_event_addr(i)))
 153                         goto perfctr_fail;
 154         }
 155 
 156         for (i = 0; i < x86_pmu.num_counters; i++) {
 157                 if (!reserve_evntsel_nmi(x86_pmu_config_addr(i)))
 158                         goto eventsel_fail;
 159         }
 160 
 161         return true;
 162 
 163 eventsel_fail:
 164         for (i--; i >= 0; i--)
 165                 release_evntsel_nmi(x86_pmu_config_addr(i));
 166 
 167         i = x86_pmu.num_counters;
 168 
 169 perfctr_fail:
 170         for (i--; i >= 0; i--)
 171                 release_perfctr_nmi(x86_pmu_event_addr(i));
 172 
 173         return false;
 174 }
 175 
 176 static void release_pmc_hardware(void)
 177 {
 178         int i;
 179 
 180         for (i = 0; i < x86_pmu.num_counters; i++) {
 181                 release_perfctr_nmi(x86_pmu_event_addr(i));
 182                 release_evntsel_nmi(x86_pmu_config_addr(i));
 183         }
 184 }
 185 
 186 #else
 187 
 188 static bool reserve_pmc_hardware(void) { return true; }
 189 static void release_pmc_hardware(void) {}
 190 
 191 #endif
 192 
 193 static bool check_hw_exists(void)
 194 {
 195         u64 val, val_fail = -1, val_new= ~0;
 196         int i, reg, reg_fail = -1, ret = 0;
 197         int bios_fail = 0;
 198         int reg_safe = -1;
 199 
 200         /*
 201          * Check to see if the BIOS enabled any of the counters, if so
 202          * complain and bail.
 203          */
 204         for (i = 0; i < x86_pmu.num_counters; i++) {
 205                 reg = x86_pmu_config_addr(i);
 206                 ret = rdmsrl_safe(reg, &val);
 207                 if (ret)
 208                         goto msr_fail;
 209                 if (val & ARCH_PERFMON_EVENTSEL_ENABLE) {
 210                         bios_fail = 1;
 211                         val_fail = val;
 212                         reg_fail = reg;
 213                 } else {
 214                         reg_safe = i;
 215                 }
 216         }
 217 
 218         if (x86_pmu.num_counters_fixed) {
 219                 reg = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
 220                 ret = rdmsrl_safe(reg, &val);
 221                 if (ret)
 222                         goto msr_fail;
 223                 for (i = 0; i < x86_pmu.num_counters_fixed; i++) {
 224                         if (val & (0x03 << i*4)) {
 225                                 bios_fail = 1;
 226                                 val_fail = val;
 227                                 reg_fail = reg;
 228                         }
 229                 }
 230         }
 231 
 232         /*
 233          * If all the counters are enabled, the below test will always
 234          * fail.  The tools will also become useless in this scenario.
 235          * Just fail and disable the hardware counters.
 236          */
 237 
 238         if (reg_safe == -1) {
 239                 reg = reg_safe;
 240                 goto msr_fail;
 241         }
 242 
 243         /*
 244          * Read the current value, change it and read it back to see if it
 245          * matches, this is needed to detect certain hardware emulators
 246          * (qemu/kvm) that don't trap on the MSR access and always return 0s.
 247          */
 248         reg = x86_pmu_event_addr(reg_safe);
 249         if (rdmsrl_safe(reg, &val))
 250                 goto msr_fail;
 251         val ^= 0xffffUL;
 252         ret = wrmsrl_safe(reg, val);
 253         ret |= rdmsrl_safe(reg, &val_new);
 254         if (ret || val != val_new)
 255                 goto msr_fail;
 256 
 257         /*
 258          * We still allow the PMU driver to operate:
 259          */
 260         if (bios_fail) {
 261                 pr_cont("Broken BIOS detected, complain to your hardware vendor.\n");
 262                 pr_err(FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n",
 263                               reg_fail, val_fail);
 264         }
 265 
 266         return true;
 267 
 268 msr_fail:
 269         if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 270                 pr_cont("PMU not available due to virtualization, using software events only.\n");
 271         } else {
 272                 pr_cont("Broken PMU hardware detected, using software events only.\n");
 273                 pr_err("Failed to access perfctr msr (MSR %x is %Lx)\n",
 274                        reg, val_new);
 275         }
 276 
 277         return false;
 278 }
 279 
 280 static void hw_perf_event_destroy(struct perf_event *event)
 281 {
 282         x86_release_hardware();
 283         atomic_dec(&active_events);
 284 }
 285 
 286 void hw_perf_lbr_event_destroy(struct perf_event *event)
 287 {
 288         hw_perf_event_destroy(event);
 289 
 290         /* undo the lbr/bts event accounting */
 291         x86_del_exclusive(x86_lbr_exclusive_lbr);
 292 }
 293 
 294 static inline int x86_pmu_initialized(void)
 295 {
 296         return x86_pmu.handle_irq != NULL;
 297 }
 298 
 299 static inline int
 300 set_ext_hw_attr(struct hw_perf_event *hwc, struct perf_event *event)
 301 {
 302         struct perf_event_attr *attr = &event->attr;
 303         unsigned int cache_type, cache_op, cache_result;
 304         u64 config, val;
 305 
 306         config = attr->config;
 307 
 308         cache_type = (config >> 0) & 0xff;
 309         if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
 310                 return -EINVAL;
 311         cache_type = array_index_nospec(cache_type, PERF_COUNT_HW_CACHE_MAX);
 312 
 313         cache_op = (config >>  8) & 0xff;
 314         if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
 315                 return -EINVAL;
 316         cache_op = array_index_nospec(cache_op, PERF_COUNT_HW_CACHE_OP_MAX);
 317 
 318         cache_result = (config >> 16) & 0xff;
 319         if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
 320                 return -EINVAL;
 321         cache_result = array_index_nospec(cache_result, PERF_COUNT_HW_CACHE_RESULT_MAX);
 322 
 323         val = hw_cache_event_ids[cache_type][cache_op][cache_result];
 324 
 325         if (val == 0)
 326                 return -ENOENT;
 327 
 328         if (val == -1)
 329                 return -EINVAL;
 330 
 331         hwc->config |= val;
 332         attr->config1 = hw_cache_extra_regs[cache_type][cache_op][cache_result];
 333         return x86_pmu_extra_regs(val, event);
 334 }
 335 
 336 int x86_reserve_hardware(void)
 337 {
 338         int err = 0;
 339 
 340         if (!atomic_inc_not_zero(&pmc_refcount)) {
 341                 mutex_lock(&pmc_reserve_mutex);
 342                 if (atomic_read(&pmc_refcount) == 0) {
 343                         if (!reserve_pmc_hardware())
 344                                 err = -EBUSY;
 345                         else
 346                                 reserve_ds_buffers();
 347                 }
 348                 if (!err)
 349                         atomic_inc(&pmc_refcount);
 350                 mutex_unlock(&pmc_reserve_mutex);
 351         }
 352 
 353         return err;
 354 }
 355 
 356 void x86_release_hardware(void)
 357 {
 358         if (atomic_dec_and_mutex_lock(&pmc_refcount, &pmc_reserve_mutex)) {
 359                 release_pmc_hardware();
 360                 release_ds_buffers();
 361                 mutex_unlock(&pmc_reserve_mutex);
 362         }
 363 }
 364 
 365 /*
 366  * Check if we can create event of a certain type (that no conflicting events
 367  * are present).
 368  */
 369 int x86_add_exclusive(unsigned int what)
 370 {
 371         int i;
 372 
 373         /*
 374          * When lbr_pt_coexist we allow PT to coexist with either LBR or BTS.
 375          * LBR and BTS are still mutually exclusive.
 376          */
 377         if (x86_pmu.lbr_pt_coexist && what == x86_lbr_exclusive_pt)
 378                 goto out;
 379 
 380         if (!atomic_inc_not_zero(&x86_pmu.lbr_exclusive[what])) {
 381                 mutex_lock(&pmc_reserve_mutex);
 382                 for (i = 0; i < ARRAY_SIZE(x86_pmu.lbr_exclusive); i++) {
 383                         if (i != what && atomic_read(&x86_pmu.lbr_exclusive[i]))
 384                                 goto fail_unlock;
 385                 }
 386                 atomic_inc(&x86_pmu.lbr_exclusive[what]);
 387                 mutex_unlock(&pmc_reserve_mutex);
 388         }
 389 
 390 out:
 391         atomic_inc(&active_events);
 392         return 0;
 393 
 394 fail_unlock:
 395         mutex_unlock(&pmc_reserve_mutex);
 396         return -EBUSY;
 397 }
 398 
 399 void x86_del_exclusive(unsigned int what)
 400 {
 401         atomic_dec(&active_events);
 402 
 403         /*
 404          * See the comment in x86_add_exclusive().
 405          */
 406         if (x86_pmu.lbr_pt_coexist && what == x86_lbr_exclusive_pt)
 407                 return;
 408 
 409         atomic_dec(&x86_pmu.lbr_exclusive[what]);
 410 }
 411 
 412 int x86_setup_perfctr(struct perf_event *event)
 413 {
 414         struct perf_event_attr *attr = &event->attr;
 415         struct hw_perf_event *hwc = &event->hw;
 416         u64 config;
 417 
 418         if (!is_sampling_event(event)) {
 419                 hwc->sample_period = x86_pmu.max_period;
 420                 hwc->last_period = hwc->sample_period;
 421                 local64_set(&hwc->period_left, hwc->sample_period);
 422         }
 423 
 424         if (attr->type == PERF_TYPE_RAW)
 425                 return x86_pmu_extra_regs(event->attr.config, event);
 426 
 427         if (attr->type == PERF_TYPE_HW_CACHE)
 428                 return set_ext_hw_attr(hwc, event);
 429 
 430         if (attr->config >= x86_pmu.max_events)
 431                 return -EINVAL;
 432 
 433         attr->config = array_index_nospec((unsigned long)attr->config, x86_pmu.max_events);
 434 
 435         /*
 436          * The generic map:
 437          */
 438         config = x86_pmu.event_map(attr->config);
 439 
 440         if (config == 0)
 441                 return -ENOENT;
 442 
 443         if (config == -1LL)
 444                 return -EINVAL;
 445 
 446         hwc->config |= config;
 447 
 448         return 0;
 449 }
 450 
 451 /*
 452  * check that branch_sample_type is compatible with
 453  * settings needed for precise_ip > 1 which implies
 454  * using the LBR to capture ALL taken branches at the
 455  * priv levels of the measurement
 456  */
 457 static inline int precise_br_compat(struct perf_event *event)
 458 {
 459         u64 m = event->attr.branch_sample_type;
 460         u64 b = 0;
 461 
 462         /* must capture all branches */
 463         if (!(m & PERF_SAMPLE_BRANCH_ANY))
 464                 return 0;
 465 
 466         m &= PERF_SAMPLE_BRANCH_KERNEL | PERF_SAMPLE_BRANCH_USER;
 467 
 468         if (!event->attr.exclude_user)
 469                 b |= PERF_SAMPLE_BRANCH_USER;
 470 
 471         if (!event->attr.exclude_kernel)
 472                 b |= PERF_SAMPLE_BRANCH_KERNEL;
 473 
 474         /*
 475          * ignore PERF_SAMPLE_BRANCH_HV, not supported on x86
 476          */
 477 
 478         return m == b;
 479 }
 480 
 481 int x86_pmu_max_precise(void)
 482 {
 483         int precise = 0;
 484 
 485         /* Support for constant skid */
 486         if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) {
 487                 precise++;
 488 
 489                 /* Support for IP fixup */
 490                 if (x86_pmu.lbr_nr || x86_pmu.intel_cap.pebs_format >= 2)
 491                         precise++;
 492 
 493                 if (x86_pmu.pebs_prec_dist)
 494                         precise++;
 495         }
 496         return precise;
 497 }
 498 
 499 int x86_pmu_hw_config(struct perf_event *event)
 500 {
 501         if (event->attr.precise_ip) {
 502                 int precise = x86_pmu_max_precise();
 503 
 504                 if (event->attr.precise_ip > precise)
 505                         return -EOPNOTSUPP;
 506 
 507                 /* There's no sense in having PEBS for non sampling events: */
 508                 if (!is_sampling_event(event))
 509                         return -EINVAL;
 510         }
 511         /*
 512          * check that PEBS LBR correction does not conflict with
 513          * whatever the user is asking with attr->branch_sample_type
 514          */
 515         if (event->attr.precise_ip > 1 && x86_pmu.intel_cap.pebs_format < 2) {
 516                 u64 *br_type = &event->attr.branch_sample_type;
 517 
 518                 if (has_branch_stack(event)) {
 519                         if (!precise_br_compat(event))
 520                                 return -EOPNOTSUPP;
 521 
 522                         /* branch_sample_type is compatible */
 523 
 524                 } else {
 525                         /*
 526                          * user did not specify  branch_sample_type
 527                          *
 528                          * For PEBS fixups, we capture all
 529                          * the branches at the priv level of the
 530                          * event.
 531                          */
 532                         *br_type = PERF_SAMPLE_BRANCH_ANY;
 533 
 534                         if (!event->attr.exclude_user)
 535                                 *br_type |= PERF_SAMPLE_BRANCH_USER;
 536 
 537                         if (!event->attr.exclude_kernel)
 538                                 *br_type |= PERF_SAMPLE_BRANCH_KERNEL;
 539                 }
 540         }
 541 
 542         if (event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_CALL_STACK)
 543                 event->attach_state |= PERF_ATTACH_TASK_DATA;
 544 
 545         /*
 546          * Generate PMC IRQs:
 547          * (keep 'enabled' bit clear for now)
 548          */
 549         event->hw.config = ARCH_PERFMON_EVENTSEL_INT;
 550 
 551         /*
 552          * Count user and OS events unless requested not to
 553          */
 554         if (!event->attr.exclude_user)
 555                 event->hw.config |= ARCH_PERFMON_EVENTSEL_USR;
 556         if (!event->attr.exclude_kernel)
 557                 event->hw.config |= ARCH_PERFMON_EVENTSEL_OS;
 558 
 559         if (event->attr.type == PERF_TYPE_RAW)
 560                 event->hw.config |= event->attr.config & X86_RAW_EVENT_MASK;
 561 
 562         if (event->attr.sample_period && x86_pmu.limit_period) {
 563                 if (x86_pmu.limit_period(event, event->attr.sample_period) >
 564                                 event->attr.sample_period)
 565                         return -EINVAL;
 566         }
 567 
 568         /* sample_regs_user never support XMM registers */
 569         if (unlikely(event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK))
 570                 return -EINVAL;
 571         /*
 572          * Besides the general purpose registers, XMM registers may
 573          * be collected in PEBS on some platforms, e.g. Icelake
 574          */
 575         if (unlikely(event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK)) {
 576                 if (!(event->pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS))
 577                         return -EINVAL;
 578 
 579                 if (!event->attr.precise_ip)
 580                         return -EINVAL;
 581         }
 582 
 583         return x86_setup_perfctr(event);
 584 }
 585 
 586 /*
 587  * Setup the hardware configuration for a given attr_type
 588  */
 589 static int __x86_pmu_event_init(struct perf_event *event)
 590 {
 591         int err;
 592 
 593         if (!x86_pmu_initialized())
 594                 return -ENODEV;
 595 
 596         err = x86_reserve_hardware();
 597         if (err)
 598                 return err;
 599 
 600         atomic_inc(&active_events);
 601         event->destroy = hw_perf_event_destroy;
 602 
 603         event->hw.idx = -1;
 604         event->hw.last_cpu = -1;
 605         event->hw.last_tag = ~0ULL;
 606 
 607         /* mark unused */
 608         event->hw.extra_reg.idx = EXTRA_REG_NONE;
 609         event->hw.branch_reg.idx = EXTRA_REG_NONE;
 610 
 611         return x86_pmu.hw_config(event);
 612 }
 613 
 614 void x86_pmu_disable_all(void)
 615 {
 616         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 617         int idx;
 618 
 619         for (idx = 0; idx < x86_pmu.num_counters; idx++) {
 620                 u64 val;
 621 
 622                 if (!test_bit(idx, cpuc->active_mask))
 623                         continue;
 624                 rdmsrl(x86_pmu_config_addr(idx), val);
 625                 if (!(val & ARCH_PERFMON_EVENTSEL_ENABLE))
 626                         continue;
 627                 val &= ~ARCH_PERFMON_EVENTSEL_ENABLE;
 628                 wrmsrl(x86_pmu_config_addr(idx), val);
 629         }
 630 }
 631 
 632 /*
 633  * There may be PMI landing after enabled=0. The PMI hitting could be before or
 634  * after disable_all.
 635  *
 636  * If PMI hits before disable_all, the PMU will be disabled in the NMI handler.
 637  * It will not be re-enabled in the NMI handler again, because enabled=0. After
 638  * handling the NMI, disable_all will be called, which will not change the
 639  * state either. If PMI hits after disable_all, the PMU is already disabled
 640  * before entering NMI handler. The NMI handler will not change the state
 641  * either.
 642  *
 643  * So either situation is harmless.
 644  */
 645 static void x86_pmu_disable(struct pmu *pmu)
 646 {
 647         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 648 
 649         if (!x86_pmu_initialized())
 650                 return;
 651 
 652         if (!cpuc->enabled)
 653                 return;
 654 
 655         cpuc->n_added = 0;
 656         cpuc->enabled = 0;
 657         barrier();
 658 
 659         x86_pmu.disable_all();
 660 }
 661 
 662 void x86_pmu_enable_all(int added)
 663 {
 664         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 665         int idx;
 666 
 667         for (idx = 0; idx < x86_pmu.num_counters; idx++) {
 668                 struct hw_perf_event *hwc = &cpuc->events[idx]->hw;
 669 
 670                 if (!test_bit(idx, cpuc->active_mask))
 671                         continue;
 672 
 673                 __x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE);
 674         }
 675 }
 676 
 677 static struct pmu pmu;
 678 
 679 static inline int is_x86_event(struct perf_event *event)
 680 {
 681         return event->pmu == &pmu;
 682 }
 683 
 684 struct pmu *x86_get_pmu(void)
 685 {
 686         return &pmu;
 687 }
 688 /*
 689  * Event scheduler state:
 690  *
 691  * Assign events iterating over all events and counters, beginning
 692  * with events with least weights first. Keep the current iterator
 693  * state in struct sched_state.
 694  */
 695 struct sched_state {
 696         int     weight;
 697         int     event;          /* event index */
 698         int     counter;        /* counter index */
 699         int     unassigned;     /* number of events to be assigned left */
 700         int     nr_gp;          /* number of GP counters used */
 701         unsigned long used[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
 702 };
 703 
 704 /* Total max is X86_PMC_IDX_MAX, but we are O(n!) limited */
 705 #define SCHED_STATES_MAX        2
 706 
 707 struct perf_sched {
 708         int                     max_weight;
 709         int                     max_events;
 710         int                     max_gp;
 711         int                     saved_states;
 712         struct event_constraint **constraints;
 713         struct sched_state      state;
 714         struct sched_state      saved[SCHED_STATES_MAX];
 715 };
 716 
 717 /*
 718  * Initialize interator that runs through all events and counters.
 719  */
 720 static void perf_sched_init(struct perf_sched *sched, struct event_constraint **constraints,
 721                             int num, int wmin, int wmax, int gpmax)
 722 {
 723         int idx;
 724 
 725         memset(sched, 0, sizeof(*sched));
 726         sched->max_events       = num;
 727         sched->max_weight       = wmax;
 728         sched->max_gp           = gpmax;
 729         sched->constraints      = constraints;
 730 
 731         for (idx = 0; idx < num; idx++) {
 732                 if (constraints[idx]->weight == wmin)
 733                         break;
 734         }
 735 
 736         sched->state.event      = idx;          /* start with min weight */
 737         sched->state.weight     = wmin;
 738         sched->state.unassigned = num;
 739 }
 740 
 741 static void perf_sched_save_state(struct perf_sched *sched)
 742 {
 743         if (WARN_ON_ONCE(sched->saved_states >= SCHED_STATES_MAX))
 744                 return;
 745 
 746         sched->saved[sched->saved_states] = sched->state;
 747         sched->saved_states++;
 748 }
 749 
 750 static bool perf_sched_restore_state(struct perf_sched *sched)
 751 {
 752         if (!sched->saved_states)
 753                 return false;
 754 
 755         sched->saved_states--;
 756         sched->state = sched->saved[sched->saved_states];
 757 
 758         /* continue with next counter: */
 759         clear_bit(sched->state.counter++, sched->state.used);
 760 
 761         return true;
 762 }
 763 
 764 /*
 765  * Select a counter for the current event to schedule. Return true on
 766  * success.
 767  */
 768 static bool __perf_sched_find_counter(struct perf_sched *sched)
 769 {
 770         struct event_constraint *c;
 771         int idx;
 772 
 773         if (!sched->state.unassigned)
 774                 return false;
 775 
 776         if (sched->state.event >= sched->max_events)
 777                 return false;
 778 
 779         c = sched->constraints[sched->state.event];
 780         /* Prefer fixed purpose counters */
 781         if (c->idxmsk64 & (~0ULL << INTEL_PMC_IDX_FIXED)) {
 782                 idx = INTEL_PMC_IDX_FIXED;
 783                 for_each_set_bit_from(idx, c->idxmsk, X86_PMC_IDX_MAX) {
 784                         if (!__test_and_set_bit(idx, sched->state.used))
 785                                 goto done;
 786                 }
 787         }
 788 
 789         /* Grab the first unused counter starting with idx */
 790         idx = sched->state.counter;
 791         for_each_set_bit_from(idx, c->idxmsk, INTEL_PMC_IDX_FIXED) {
 792                 if (!__test_and_set_bit(idx, sched->state.used)) {
 793                         if (sched->state.nr_gp++ >= sched->max_gp)
 794                                 return false;
 795 
 796                         goto done;
 797                 }
 798         }
 799 
 800         return false;
 801 
 802 done:
 803         sched->state.counter = idx;
 804 
 805         if (c->overlap)
 806                 perf_sched_save_state(sched);
 807 
 808         return true;
 809 }
 810 
 811 static bool perf_sched_find_counter(struct perf_sched *sched)
 812 {
 813         while (!__perf_sched_find_counter(sched)) {
 814                 if (!perf_sched_restore_state(sched))
 815                         return false;
 816         }
 817 
 818         return true;
 819 }
 820 
 821 /*
 822  * Go through all unassigned events and find the next one to schedule.
 823  * Take events with the least weight first. Return true on success.
 824  */
 825 static bool perf_sched_next_event(struct perf_sched *sched)
 826 {
 827         struct event_constraint *c;
 828 
 829         if (!sched->state.unassigned || !--sched->state.unassigned)
 830                 return false;
 831 
 832         do {
 833                 /* next event */
 834                 sched->state.event++;
 835                 if (sched->state.event >= sched->max_events) {
 836                         /* next weight */
 837                         sched->state.event = 0;
 838                         sched->state.weight++;
 839                         if (sched->state.weight > sched->max_weight)
 840                                 return false;
 841                 }
 842                 c = sched->constraints[sched->state.event];
 843         } while (c->weight != sched->state.weight);
 844 
 845         sched->state.counter = 0;       /* start with first counter */
 846 
 847         return true;
 848 }
 849 
 850 /*
 851  * Assign a counter for each event.
 852  */
 853 int perf_assign_events(struct event_constraint **constraints, int n,
 854                         int wmin, int wmax, int gpmax, int *assign)
 855 {
 856         struct perf_sched sched;
 857 
 858         perf_sched_init(&sched, constraints, n, wmin, wmax, gpmax);
 859 
 860         do {
 861                 if (!perf_sched_find_counter(&sched))
 862                         break;  /* failed */
 863                 if (assign)
 864                         assign[sched.state.event] = sched.state.counter;
 865         } while (perf_sched_next_event(&sched));
 866 
 867         return sched.state.unassigned;
 868 }
 869 EXPORT_SYMBOL_GPL(perf_assign_events);
 870 
 871 int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
 872 {
 873         struct event_constraint *c;
 874         unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
 875         struct perf_event *e;
 876         int n0, i, wmin, wmax, unsched = 0;
 877         struct hw_perf_event *hwc;
 878 
 879         bitmap_zero(used_mask, X86_PMC_IDX_MAX);
 880 
 881         /*
 882          * Compute the number of events already present; see x86_pmu_add(),
 883          * validate_group() and x86_pmu_commit_txn(). For the former two
 884          * cpuc->n_events hasn't been updated yet, while for the latter
 885          * cpuc->n_txn contains the number of events added in the current
 886          * transaction.
 887          */
 888         n0 = cpuc->n_events;
 889         if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
 890                 n0 -= cpuc->n_txn;
 891 
 892         if (x86_pmu.start_scheduling)
 893                 x86_pmu.start_scheduling(cpuc);
 894 
 895         for (i = 0, wmin = X86_PMC_IDX_MAX, wmax = 0; i < n; i++) {
 896                 c = cpuc->event_constraint[i];
 897 
 898                 /*
 899                  * Previously scheduled events should have a cached constraint,
 900                  * while new events should not have one.
 901                  */
 902                 WARN_ON_ONCE((c && i >= n0) || (!c && i < n0));
 903 
 904                 /*
 905                  * Request constraints for new events; or for those events that
 906                  * have a dynamic constraint -- for those the constraint can
 907                  * change due to external factors (sibling state, allow_tfa).
 908                  */
 909                 if (!c || (c->flags & PERF_X86_EVENT_DYNAMIC)) {
 910                         c = x86_pmu.get_event_constraints(cpuc, i, cpuc->event_list[i]);
 911                         cpuc->event_constraint[i] = c;
 912                 }
 913 
 914                 wmin = min(wmin, c->weight);
 915                 wmax = max(wmax, c->weight);
 916         }
 917 
 918         /*
 919          * fastpath, try to reuse previous register
 920          */
 921         for (i = 0; i < n; i++) {
 922                 hwc = &cpuc->event_list[i]->hw;
 923                 c = cpuc->event_constraint[i];
 924 
 925                 /* never assigned */
 926                 if (hwc->idx == -1)
 927                         break;
 928 
 929                 /* constraint still honored */
 930                 if (!test_bit(hwc->idx, c->idxmsk))
 931                         break;
 932 
 933                 /* not already used */
 934                 if (test_bit(hwc->idx, used_mask))
 935                         break;
 936 
 937                 __set_bit(hwc->idx, used_mask);
 938                 if (assign)
 939                         assign[i] = hwc->idx;
 940         }
 941 
 942         /* slow path */
 943         if (i != n) {
 944                 int gpmax = x86_pmu.num_counters;
 945 
 946                 /*
 947                  * Do not allow scheduling of more than half the available
 948                  * generic counters.
 949                  *
 950                  * This helps avoid counter starvation of sibling thread by
 951                  * ensuring at most half the counters cannot be in exclusive
 952                  * mode. There is no designated counters for the limits. Any
 953                  * N/2 counters can be used. This helps with events with
 954                  * specific counter constraints.
 955                  */
 956                 if (is_ht_workaround_enabled() && !cpuc->is_fake &&
 957                     READ_ONCE(cpuc->excl_cntrs->exclusive_present))
 958                         gpmax /= 2;
 959 
 960                 unsched = perf_assign_events(cpuc->event_constraint, n, wmin,
 961                                              wmax, gpmax, assign);
 962         }
 963 
 964         /*
 965          * In case of success (unsched = 0), mark events as committed,
 966          * so we do not put_constraint() in case new events are added
 967          * and fail to be scheduled
 968          *
 969          * We invoke the lower level commit callback to lock the resource
 970          *
 971          * We do not need to do all of this in case we are called to
 972          * validate an event group (assign == NULL)
 973          */
 974         if (!unsched && assign) {
 975                 for (i = 0; i < n; i++) {
 976                         e = cpuc->event_list[i];
 977                         if (x86_pmu.commit_scheduling)
 978                                 x86_pmu.commit_scheduling(cpuc, i, assign[i]);
 979                 }
 980         } else {
 981                 for (i = n0; i < n; i++) {
 982                         e = cpuc->event_list[i];
 983 
 984                         /*
 985                          * release events that failed scheduling
 986                          */
 987                         if (x86_pmu.put_event_constraints)
 988                                 x86_pmu.put_event_constraints(cpuc, e);
 989 
 990                         cpuc->event_constraint[i] = NULL;
 991                 }
 992         }
 993 
 994         if (x86_pmu.stop_scheduling)
 995                 x86_pmu.stop_scheduling(cpuc);
 996 
 997         return unsched ? -EINVAL : 0;
 998 }
 999 
1000 /*
1001  * dogrp: true if must collect siblings events (group)
1002  * returns total number of events and error code
1003  */
1004 static int collect_events(struct cpu_hw_events *cpuc, struct perf_event *leader, bool dogrp)
1005 {
1006         struct perf_event *event;
1007         int n, max_count;
1008 
1009         max_count = x86_pmu.num_counters + x86_pmu.num_counters_fixed;
1010 
1011         /* current number of events already accepted */
1012         n = cpuc->n_events;
1013         if (!cpuc->n_events)
1014                 cpuc->pebs_output = 0;
1015 
1016         if (!cpuc->is_fake && leader->attr.precise_ip) {
1017                 /*
1018                  * For PEBS->PT, if !aux_event, the group leader (PT) went
1019                  * away, the group was broken down and this singleton event
1020                  * can't schedule any more.
1021                  */
1022                 if (is_pebs_pt(leader) && !leader->aux_event)
1023                         return -EINVAL;
1024 
1025                 /*
1026                  * pebs_output: 0: no PEBS so far, 1: PT, 2: DS
1027                  */
1028                 if (cpuc->pebs_output &&
1029                     cpuc->pebs_output != is_pebs_pt(leader) + 1)
1030                         return -EINVAL;
1031 
1032                 cpuc->pebs_output = is_pebs_pt(leader) + 1;
1033         }
1034 
1035         if (is_x86_event(leader)) {
1036                 if (n >= max_count)
1037                         return -EINVAL;
1038                 cpuc->event_list[n] = leader;
1039                 n++;
1040         }
1041         if (!dogrp)
1042                 return n;
1043 
1044         for_each_sibling_event(event, leader) {
1045                 if (!is_x86_event(event) ||
1046                     event->state <= PERF_EVENT_STATE_OFF)
1047                         continue;
1048 
1049                 if (n >= max_count)
1050                         return -EINVAL;
1051 
1052                 cpuc->event_list[n] = event;
1053                 n++;
1054         }
1055         return n;
1056 }
1057 
1058 static inline void x86_assign_hw_event(struct perf_event *event,
1059                                 struct cpu_hw_events *cpuc, int i)
1060 {
1061         struct hw_perf_event *hwc = &event->hw;
1062 
1063         hwc->idx = cpuc->assign[i];
1064         hwc->last_cpu = smp_processor_id();
1065         hwc->last_tag = ++cpuc->tags[i];
1066 
1067         if (hwc->idx == INTEL_PMC_IDX_FIXED_BTS) {
1068                 hwc->config_base = 0;
1069                 hwc->event_base = 0;
1070         } else if (hwc->idx >= INTEL_PMC_IDX_FIXED) {
1071                 hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
1072                 hwc->event_base = MSR_ARCH_PERFMON_FIXED_CTR0 + (hwc->idx - INTEL_PMC_IDX_FIXED);
1073                 hwc->event_base_rdpmc = (hwc->idx - INTEL_PMC_IDX_FIXED) | 1<<30;
1074         } else {
1075                 hwc->config_base = x86_pmu_config_addr(hwc->idx);
1076                 hwc->event_base  = x86_pmu_event_addr(hwc->idx);
1077                 hwc->event_base_rdpmc = x86_pmu_rdpmc_index(hwc->idx);
1078         }
1079 }
1080 
1081 /**
1082  * x86_perf_rdpmc_index - Return PMC counter used for event
1083  * @event: the perf_event to which the PMC counter was assigned
1084  *
1085  * The counter assigned to this performance event may change if interrupts
1086  * are enabled. This counter should thus never be used while interrupts are
1087  * enabled. Before this function is used to obtain the assigned counter the
1088  * event should be checked for validity using, for example,
1089  * perf_event_read_local(), within the same interrupt disabled section in
1090  * which this counter is planned to be used.
1091  *
1092  * Return: The index of the performance monitoring counter assigned to
1093  * @perf_event.
1094  */
1095 int x86_perf_rdpmc_index(struct perf_event *event)
1096 {
1097         lockdep_assert_irqs_disabled();
1098 
1099         return event->hw.event_base_rdpmc;
1100 }
1101 
1102 static inline int match_prev_assignment(struct hw_perf_event *hwc,
1103                                         struct cpu_hw_events *cpuc,
1104                                         int i)
1105 {
1106         return hwc->idx == cpuc->assign[i] &&
1107                 hwc->last_cpu == smp_processor_id() &&
1108                 hwc->last_tag == cpuc->tags[i];
1109 }
1110 
1111 static void x86_pmu_start(struct perf_event *event, int flags);
1112 
1113 static void x86_pmu_enable(struct pmu *pmu)
1114 {
1115         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
1116         struct perf_event *event;
1117         struct hw_perf_event *hwc;
1118         int i, added = cpuc->n_added;
1119 
1120         if (!x86_pmu_initialized())
1121                 return;
1122 
1123         if (cpuc->enabled)
1124                 return;
1125 
1126         if (cpuc->n_added) {
1127                 int n_running = cpuc->n_events - cpuc->n_added;
1128                 /*
1129                  * apply assignment obtained either from
1130                  * hw_perf_group_sched_in() or x86_pmu_enable()
1131                  *
1132                  * step1: save events moving to new counters
1133                  */
1134                 for (i = 0; i < n_running; i++) {
1135                         event = cpuc->event_list[i];
1136                         hwc = &event->hw;
1137 
1138                         /*
1139                          * we can avoid reprogramming counter if:
1140                          * - assigned same counter as last time
1141                          * - running on same CPU as last time
1142                          * - no other event has used the counter since
1143                          */
1144                         if (hwc->idx == -1 ||
1145                             match_prev_assignment(hwc, cpuc, i))
1146                                 continue;
1147 
1148                         /*
1149                          * Ensure we don't accidentally enable a stopped
1150                          * counter simply because we rescheduled.
1151                          */
1152                         if (hwc->state & PERF_HES_STOPPED)
1153                                 hwc->state |= PERF_HES_ARCH;
1154 
1155                         x86_pmu_stop(event, PERF_EF_UPDATE);
1156                 }
1157 
1158                 /*
1159                  * step2: reprogram moved events into new counters
1160                  */
1161                 for (i = 0; i < cpuc->n_events; i++) {
1162                         event = cpuc->event_list[i];
1163                         hwc = &event->hw;
1164 
1165                         if (!match_prev_assignment(hwc, cpuc, i))
1166                                 x86_assign_hw_event(event, cpuc, i);
1167                         else if (i < n_running)
1168                                 continue;
1169 
1170                         if (hwc->state & PERF_HES_ARCH)
1171                                 continue;
1172 
1173                         x86_pmu_start(event, PERF_EF_RELOAD);
1174                 }
1175                 cpuc->n_added = 0;
1176                 perf_events_lapic_init();
1177         }
1178 
1179         cpuc->enabled = 1;
1180         barrier();
1181 
1182         x86_pmu.enable_all(added);
1183 }
1184 
1185 static DEFINE_PER_CPU(u64 [X86_PMC_IDX_MAX], pmc_prev_left);
1186 
1187 /*
1188  * Set the next IRQ period, based on the hwc->period_left value.
1189  * To be called with the event disabled in hw:
1190  */
1191 int x86_perf_event_set_period(struct perf_event *event)
1192 {
1193         struct hw_perf_event *hwc = &event->hw;
1194         s64 left = local64_read(&hwc->period_left);
1195         s64 period = hwc->sample_period;
1196         int ret = 0, idx = hwc->idx;
1197 
1198         if (idx == INTEL_PMC_IDX_FIXED_BTS)
1199                 return 0;
1200 
1201         /*
1202          * If we are way outside a reasonable range then just skip forward:
1203          */
1204         if (unlikely(left <= -period)) {
1205                 left = period;
1206                 local64_set(&hwc->period_left, left);
1207                 hwc->last_period = period;
1208                 ret = 1;
1209         }
1210 
1211         if (unlikely(left <= 0)) {
1212                 left += period;
1213                 local64_set(&hwc->period_left, left);
1214                 hwc->last_period = period;
1215                 ret = 1;
1216         }
1217         /*
1218          * Quirk: certain CPUs dont like it if just 1 hw_event is left:
1219          */
1220         if (unlikely(left < 2))
1221                 left = 2;
1222 
1223         if (left > x86_pmu.max_period)
1224                 left = x86_pmu.max_period;
1225 
1226         if (x86_pmu.limit_period)
1227                 left = x86_pmu.limit_period(event, left);
1228 
1229         per_cpu(pmc_prev_left[idx], smp_processor_id()) = left;
1230 
1231         /*
1232          * The hw event starts counting from this event offset,
1233          * mark it to be able to extra future deltas:
1234          */
1235         local64_set(&hwc->prev_count, (u64)-left);
1236 
1237         wrmsrl(hwc->event_base, (u64)(-left) & x86_pmu.cntval_mask);
1238 
1239         /*
1240          * Due to erratum on certan cpu we need
1241          * a second write to be sure the register
1242          * is updated properly
1243          */
1244         if (x86_pmu.perfctr_second_write) {
1245                 wrmsrl(hwc->event_base,
1246                         (u64)(-left) & x86_pmu.cntval_mask);
1247         }
1248 
1249         perf_event_update_userpage(event);
1250 
1251         return ret;
1252 }
1253 
1254 void x86_pmu_enable_event(struct perf_event *event)
1255 {
1256         if (__this_cpu_read(cpu_hw_events.enabled))
1257                 __x86_pmu_enable_event(&event->hw,
1258                                        ARCH_PERFMON_EVENTSEL_ENABLE);
1259 }
1260 
1261 /*
1262  * Add a single event to the PMU.
1263  *
1264  * The event is added to the group of enabled events
1265  * but only if it can be scheduled with existing events.
1266  */
1267 static int x86_pmu_add(struct perf_event *event, int flags)
1268 {
1269         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
1270         struct hw_perf_event *hwc;
1271         int assign[X86_PMC_IDX_MAX];
1272         int n, n0, ret;
1273 
1274         hwc = &event->hw;
1275 
1276         n0 = cpuc->n_events;
1277         ret = n = collect_events(cpuc, event, false);
1278         if (ret < 0)
1279                 goto out;
1280 
1281         hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
1282         if (!(flags & PERF_EF_START))
1283                 hwc->state |= PERF_HES_ARCH;
1284 
1285         /*
1286          * If group events scheduling transaction was started,
1287          * skip the schedulability test here, it will be performed
1288          * at commit time (->commit_txn) as a whole.
1289          *
1290          * If commit fails, we'll call ->del() on all events
1291          * for which ->add() was called.
1292          */
1293         if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
1294                 goto done_collect;
1295 
1296         ret = x86_pmu.schedule_events(cpuc, n, assign);
1297         if (ret)
1298                 goto out;
1299         /*
1300          * copy new assignment, now we know it is possible
1301          * will be used by hw_perf_enable()
1302          */
1303         memcpy(cpuc->assign, assign, n*sizeof(int));
1304 
1305 done_collect:
1306         /*
1307          * Commit the collect_events() state. See x86_pmu_del() and
1308          * x86_pmu_*_txn().
1309          */
1310         cpuc->n_events = n;
1311         cpuc->n_added += n - n0;
1312         cpuc->n_txn += n - n0;
1313 
1314         if (x86_pmu.add) {
1315                 /*
1316                  * This is before x86_pmu_enable() will call x86_pmu_start(),
1317                  * so we enable LBRs before an event needs them etc..
1318                  */
1319                 x86_pmu.add(event);
1320         }
1321 
1322         ret = 0;
1323 out:
1324         return ret;
1325 }
1326 
1327 static void x86_pmu_start(struct perf_event *event, int flags)
1328 {
1329         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
1330         int idx = event->hw.idx;
1331 
1332         if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
1333                 return;
1334 
1335         if (WARN_ON_ONCE(idx == -1))
1336                 return;
1337 
1338         if (flags & PERF_EF_RELOAD) {
1339                 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
1340                 x86_perf_event_set_period(event);
1341         }
1342 
1343         event->hw.state = 0;
1344 
1345         cpuc->events[idx] = event;
1346         __set_bit(idx, cpuc->active_mask);
1347         __set_bit(idx, cpuc->running);
1348         x86_pmu.enable(event);
1349         perf_event_update_userpage(event);
1350 }
1351 
1352 void perf_event_print_debug(void)
1353 {
1354         u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed;
1355         u64 pebs, debugctl;
1356         struct cpu_hw_events *cpuc;
1357         unsigned long flags;
1358         int cpu, idx;
1359 
1360         if (!x86_pmu.num_counters)
1361                 return;
1362 
1363         local_irq_save(flags);
1364 
1365         cpu = smp_processor_id();
1366         cpuc = &per_cpu(cpu_hw_events, cpu);
1367 
1368         if (x86_pmu.version >= 2) {
1369                 rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
1370                 rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
1371                 rdmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, overflow);
1372                 rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, fixed);
1373 
1374                 pr_info("\n");
1375                 pr_info("CPU#%d: ctrl:       %016llx\n", cpu, ctrl);
1376                 pr_info("CPU#%d: status:     %016llx\n", cpu, status);
1377                 pr_info("CPU#%d: overflow:   %016llx\n", cpu, overflow);
1378                 pr_info("CPU#%d: fixed:      %016llx\n", cpu, fixed);
1379                 if (x86_pmu.pebs_constraints) {
1380                         rdmsrl(MSR_IA32_PEBS_ENABLE, pebs);
1381                         pr_info("CPU#%d: pebs:       %016llx\n", cpu, pebs);
1382                 }
1383                 if (x86_pmu.lbr_nr) {
1384                         rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
1385                         pr_info("CPU#%d: debugctl:   %016llx\n", cpu, debugctl);
1386                 }
1387         }
1388         pr_info("CPU#%d: active:     %016llx\n", cpu, *(u64 *)cpuc->active_mask);
1389 
1390         for (idx = 0; idx < x86_pmu.num_counters; idx++) {
1391                 rdmsrl(x86_pmu_config_addr(idx), pmc_ctrl);
1392                 rdmsrl(x86_pmu_event_addr(idx), pmc_count);
1393 
1394                 prev_left = per_cpu(pmc_prev_left[idx], cpu);
1395 
1396                 pr_info("CPU#%d:   gen-PMC%d ctrl:  %016llx\n",
1397                         cpu, idx, pmc_ctrl);
1398                 pr_info("CPU#%d:   gen-PMC%d count: %016llx\n",
1399                         cpu, idx, pmc_count);
1400                 pr_info("CPU#%d:   gen-PMC%d left:  %016llx\n",
1401                         cpu, idx, prev_left);
1402         }
1403         for (idx = 0; idx < x86_pmu.num_counters_fixed; idx++) {
1404                 rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, pmc_count);
1405 
1406                 pr_info("CPU#%d: fixed-PMC%d count: %016llx\n",
1407                         cpu, idx, pmc_count);
1408         }
1409         local_irq_restore(flags);
1410 }
1411 
1412 void x86_pmu_stop(struct perf_event *event, int flags)
1413 {
1414         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
1415         struct hw_perf_event *hwc = &event->hw;
1416 
1417         if (test_bit(hwc->idx, cpuc->active_mask)) {
1418                 x86_pmu.disable(event);
1419                 __clear_bit(hwc->idx, cpuc->active_mask);
1420                 cpuc->events[hwc->idx] = NULL;
1421                 WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
1422                 hwc->state |= PERF_HES_STOPPED;
1423         }
1424 
1425         if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
1426                 /*
1427                  * Drain the remaining delta count out of a event
1428                  * that we are disabling:
1429                  */
1430                 x86_perf_event_update(event);
1431                 hwc->state |= PERF_HES_UPTODATE;
1432         }
1433 }
1434 
1435 static void x86_pmu_del(struct perf_event *event, int flags)
1436 {
1437         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
1438         int i;
1439 
1440         /*
1441          * If we're called during a txn, we only need to undo x86_pmu.add.
1442          * The events never got scheduled and ->cancel_txn will truncate
1443          * the event_list.
1444          *
1445          * XXX assumes any ->del() called during a TXN will only be on
1446          * an event added during that same TXN.
1447          */
1448         if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
1449                 goto do_del;
1450 
1451         /*
1452          * Not a TXN, therefore cleanup properly.
1453          */
1454         x86_pmu_stop(event, PERF_EF_UPDATE);
1455 
1456         for (i = 0; i < cpuc->n_events; i++) {
1457                 if (event == cpuc->event_list[i])
1458                         break;
1459         }
1460 
1461         if (WARN_ON_ONCE(i == cpuc->n_events)) /* called ->del() without ->add() ? */
1462                 return;
1463 
1464         /* If we have a newly added event; make sure to decrease n_added. */
1465         if (i >= cpuc->n_events - cpuc->n_added)
1466                 --cpuc->n_added;
1467 
1468         if (x86_pmu.put_event_constraints)
1469                 x86_pmu.put_event_constraints(cpuc, event);
1470 
1471         /* Delete the array entry. */
1472         while (++i < cpuc->n_events) {
1473                 cpuc->event_list[i-1] = cpuc->event_list[i];
1474                 cpuc->event_constraint[i-1] = cpuc->event_constraint[i];
1475         }
1476         cpuc->event_constraint[i-1] = NULL;
1477         --cpuc->n_events;
1478 
1479         perf_event_update_userpage(event);
1480 
1481 do_del:
1482         if (x86_pmu.del) {
1483                 /*
1484                  * This is after x86_pmu_stop(); so we disable LBRs after any
1485                  * event can need them etc..
1486                  */
1487                 x86_pmu.del(event);
1488         }
1489 }
1490 
1491 int x86_pmu_handle_irq(struct pt_regs *regs)
1492 {
1493         struct perf_sample_data data;
1494         struct cpu_hw_events *cpuc;
1495         struct perf_event *event;
1496         int idx, handled = 0;
1497         u64 val;
1498 
1499         cpuc = this_cpu_ptr(&cpu_hw_events);
1500 
1501         /*
1502          * Some chipsets need to unmask the LVTPC in a particular spot
1503          * inside the nmi handler.  As a result, the unmasking was pushed
1504          * into all the nmi handlers.
1505          *
1506          * This generic handler doesn't seem to have any issues where the
1507          * unmasking occurs so it was left at the top.
1508          */
1509         apic_write(APIC_LVTPC, APIC_DM_NMI);
1510 
1511         for (idx = 0; idx < x86_pmu.num_counters; idx++) {
1512                 if (!test_bit(idx, cpuc->active_mask))
1513                         continue;
1514 
1515                 event = cpuc->events[idx];
1516 
1517                 val = x86_perf_event_update(event);
1518                 if (val & (1ULL << (x86_pmu.cntval_bits - 1)))
1519                         continue;
1520 
1521                 /*
1522                  * event overflow
1523                  */
1524                 handled++;
1525                 perf_sample_data_init(&data, 0, event->hw.last_period);
1526 
1527                 if (!x86_perf_event_set_period(event))
1528                         continue;
1529 
1530                 if (perf_event_overflow(event, &data, regs))
1531                         x86_pmu_stop(event, 0);
1532         }
1533 
1534         if (handled)
1535                 inc_irq_stat(apic_perf_irqs);
1536 
1537         return handled;
1538 }
1539 
1540 void perf_events_lapic_init(void)
1541 {
1542         if (!x86_pmu.apic || !x86_pmu_initialized())
1543                 return;
1544 
1545         /*
1546          * Always use NMI for PMU
1547          */
1548         apic_write(APIC_LVTPC, APIC_DM_NMI);
1549 }
1550 
1551 static int
1552 perf_event_nmi_handler(unsigned int cmd, struct pt_regs *regs)
1553 {
1554         u64 start_clock;
1555         u64 finish_clock;
1556         int ret;
1557 
1558         /*
1559          * All PMUs/events that share this PMI handler should make sure to
1560          * increment active_events for their events.
1561          */
1562         if (!atomic_read(&active_events))
1563                 return NMI_DONE;
1564 
1565         start_clock = sched_clock();
1566         ret = x86_pmu.handle_irq(regs);
1567         finish_clock = sched_clock();
1568 
1569         perf_sample_event_took(finish_clock - start_clock);
1570 
1571         return ret;
1572 }
1573 NOKPROBE_SYMBOL(perf_event_nmi_handler);
1574 
1575 struct event_constraint emptyconstraint;
1576 struct event_constraint unconstrained;
1577 
1578 static int x86_pmu_prepare_cpu(unsigned int cpu)
1579 {
1580         struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
1581         int i;
1582 
1583         for (i = 0 ; i < X86_PERF_KFREE_MAX; i++)
1584                 cpuc->kfree_on_online[i] = NULL;
1585         if (x86_pmu.cpu_prepare)
1586                 return x86_pmu.cpu_prepare(cpu);
1587         return 0;
1588 }
1589 
1590 static int x86_pmu_dead_cpu(unsigned int cpu)
1591 {
1592         if (x86_pmu.cpu_dead)
1593                 x86_pmu.cpu_dead(cpu);
1594         return 0;
1595 }
1596 
1597 static int x86_pmu_online_cpu(unsigned int cpu)
1598 {
1599         struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
1600         int i;
1601 
1602         for (i = 0 ; i < X86_PERF_KFREE_MAX; i++) {
1603                 kfree(cpuc->kfree_on_online[i]);
1604                 cpuc->kfree_on_online[i] = NULL;
1605         }
1606         return 0;
1607 }
1608 
1609 static int x86_pmu_starting_cpu(unsigned int cpu)
1610 {
1611         if (x86_pmu.cpu_starting)
1612                 x86_pmu.cpu_starting(cpu);
1613         return 0;
1614 }
1615 
1616 static int x86_pmu_dying_cpu(unsigned int cpu)
1617 {
1618         if (x86_pmu.cpu_dying)
1619                 x86_pmu.cpu_dying(cpu);
1620         return 0;
1621 }
1622 
1623 static void __init pmu_check_apic(void)
1624 {
1625         if (boot_cpu_has(X86_FEATURE_APIC))
1626                 return;
1627 
1628         x86_pmu.apic = 0;
1629         pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
1630         pr_info("no hardware sampling interrupt available.\n");
1631 
1632         /*
1633          * If we have a PMU initialized but no APIC
1634          * interrupts, we cannot sample hardware
1635          * events (user-space has to fall back and
1636          * sample via a hrtimer based software event):
1637          */
1638         pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
1639 
1640 }
1641 
1642 static struct attribute_group x86_pmu_format_group __ro_after_init = {
1643         .name = "format",
1644         .attrs = NULL,
1645 };
1646 
1647 ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page)
1648 {
1649         struct perf_pmu_events_attr *pmu_attr =
1650                 container_of(attr, struct perf_pmu_events_attr, attr);
1651         u64 config = 0;
1652 
1653         if (pmu_attr->id < x86_pmu.max_events)
1654                 config = x86_pmu.event_map(pmu_attr->id);
1655 
1656         /* string trumps id */
1657         if (pmu_attr->event_str)
1658                 return sprintf(page, "%s", pmu_attr->event_str);
1659 
1660         return x86_pmu.events_sysfs_show(page, config);
1661 }
1662 EXPORT_SYMBOL_GPL(events_sysfs_show);
1663 
1664 ssize_t events_ht_sysfs_show(struct device *dev, struct device_attribute *attr,
1665                           char *page)
1666 {
1667         struct perf_pmu_events_ht_attr *pmu_attr =
1668                 container_of(attr, struct perf_pmu_events_ht_attr, attr);
1669 
1670         /*
1671          * Report conditional events depending on Hyper-Threading.
1672          *
1673          * This is overly conservative as usually the HT special
1674          * handling is not needed if the other CPU thread is idle.
1675          *
1676          * Note this does not (and cannot) handle the case when thread
1677          * siblings are invisible, for example with virtualization
1678          * if they are owned by some other guest.  The user tool
1679          * has to re-read when a thread sibling gets onlined later.
1680          */
1681         return sprintf(page, "%s",
1682                         topology_max_smt_threads() > 1 ?
1683                         pmu_attr->event_str_ht :
1684                         pmu_attr->event_str_noht);
1685 }
1686 
1687 EVENT_ATTR(cpu-cycles,                  CPU_CYCLES              );
1688 EVENT_ATTR(instructions,                INSTRUCTIONS            );
1689 EVENT_ATTR(cache-references,            CACHE_REFERENCES        );
1690 EVENT_ATTR(cache-misses,                CACHE_MISSES            );
1691 EVENT_ATTR(branch-instructions,         BRANCH_INSTRUCTIONS     );
1692 EVENT_ATTR(branch-misses,               BRANCH_MISSES           );
1693 EVENT_ATTR(bus-cycles,                  BUS_CYCLES              );
1694 EVENT_ATTR(stalled-cycles-frontend,     STALLED_CYCLES_FRONTEND );
1695 EVENT_ATTR(stalled-cycles-backend,      STALLED_CYCLES_BACKEND  );
1696 EVENT_ATTR(ref-cycles,                  REF_CPU_CYCLES          );
1697 
1698 static struct attribute *empty_attrs;
1699 
1700 static struct attribute *events_attr[] = {
1701         EVENT_PTR(CPU_CYCLES),
1702         EVENT_PTR(INSTRUCTIONS),
1703         EVENT_PTR(CACHE_REFERENCES),
1704         EVENT_PTR(CACHE_MISSES),
1705         EVENT_PTR(BRANCH_INSTRUCTIONS),
1706         EVENT_PTR(BRANCH_MISSES),
1707         EVENT_PTR(BUS_CYCLES),
1708         EVENT_PTR(STALLED_CYCLES_FRONTEND),
1709         EVENT_PTR(STALLED_CYCLES_BACKEND),
1710         EVENT_PTR(REF_CPU_CYCLES),
1711         NULL,
1712 };
1713 
1714 /*
1715  * Remove all undefined events (x86_pmu.event_map(id) == 0)
1716  * out of events_attr attributes.
1717  */
1718 static umode_t
1719 is_visible(struct kobject *kobj, struct attribute *attr, int idx)
1720 {
1721         struct perf_pmu_events_attr *pmu_attr;
1722 
1723         if (idx >= x86_pmu.max_events)
1724                 return 0;
1725 
1726         pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr.attr);
1727         /* str trumps id */
1728         return pmu_attr->event_str || x86_pmu.event_map(idx) ? attr->mode : 0;
1729 }
1730 
1731 static struct attribute_group x86_pmu_events_group __ro_after_init = {
1732         .name = "events",
1733         .attrs = events_attr,
1734         .is_visible = is_visible,
1735 };
1736 
1737 ssize_t x86_event_sysfs_show(char *page, u64 config, u64 event)
1738 {
1739         u64 umask  = (config & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
1740         u64 cmask  = (config & ARCH_PERFMON_EVENTSEL_CMASK) >> 24;
1741         bool edge  = (config & ARCH_PERFMON_EVENTSEL_EDGE);
1742         bool pc    = (config & ARCH_PERFMON_EVENTSEL_PIN_CONTROL);
1743         bool any   = (config & ARCH_PERFMON_EVENTSEL_ANY);
1744         bool inv   = (config & ARCH_PERFMON_EVENTSEL_INV);
1745         ssize_t ret;
1746 
1747         /*
1748         * We have whole page size to spend and just little data
1749         * to write, so we can safely use sprintf.
1750         */
1751         ret = sprintf(page, "event=0x%02llx", event);
1752 
1753         if (umask)
1754                 ret += sprintf(page + ret, ",umask=0x%02llx", umask);
1755 
1756         if (edge)
1757                 ret += sprintf(page + ret, ",edge");
1758 
1759         if (pc)
1760                 ret += sprintf(page + ret, ",pc");
1761 
1762         if (any)
1763                 ret += sprintf(page + ret, ",any");
1764 
1765         if (inv)
1766                 ret += sprintf(page + ret, ",inv");
1767 
1768         if (cmask)
1769                 ret += sprintf(page + ret, ",cmask=0x%02llx", cmask);
1770 
1771         ret += sprintf(page + ret, "\n");
1772 
1773         return ret;
1774 }
1775 
1776 static struct attribute_group x86_pmu_attr_group;
1777 static struct attribute_group x86_pmu_caps_group;
1778 
1779 static int __init init_hw_perf_events(void)
1780 {
1781         struct x86_pmu_quirk *quirk;
1782         int err;
1783 
1784         pr_info("Performance Events: ");
1785 
1786         switch (boot_cpu_data.x86_vendor) {
1787         case X86_VENDOR_INTEL:
1788                 err = intel_pmu_init();
1789                 break;
1790         case X86_VENDOR_AMD:
1791                 err = amd_pmu_init();
1792                 break;
1793         case X86_VENDOR_HYGON:
1794                 err = amd_pmu_init();
1795                 x86_pmu.name = "HYGON";
1796                 break;
1797         default:
1798                 err = -ENOTSUPP;
1799         }
1800         if (err != 0) {
1801                 pr_cont("no PMU driver, software events only.\n");
1802                 return 0;
1803         }
1804 
1805         pmu_check_apic();
1806 
1807         /* sanity check that the hardware exists or is emulated */
1808         if (!check_hw_exists())
1809                 return 0;
1810 
1811         pr_cont("%s PMU driver.\n", x86_pmu.name);
1812 
1813         x86_pmu.attr_rdpmc = 1; /* enable userspace RDPMC usage by default */
1814 
1815         for (quirk = x86_pmu.quirks; quirk; quirk = quirk->next)
1816                 quirk->func();
1817 
1818         if (!x86_pmu.intel_ctrl)
1819                 x86_pmu.intel_ctrl = (1 << x86_pmu.num_counters) - 1;
1820 
1821         perf_events_lapic_init();
1822         register_nmi_handler(NMI_LOCAL, perf_event_nmi_handler, 0, "PMI");
1823 
1824         unconstrained = (struct event_constraint)
1825                 __EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_counters) - 1,
1826                                    0, x86_pmu.num_counters, 0, 0);
1827 
1828         x86_pmu_format_group.attrs = x86_pmu.format_attrs;
1829 
1830         if (!x86_pmu.events_sysfs_show)
1831                 x86_pmu_events_group.attrs = &empty_attrs;
1832 
1833         pmu.attr_update = x86_pmu.attr_update;
1834 
1835         pr_info("... version:                %d\n",     x86_pmu.version);
1836         pr_info("... bit width:              %d\n",     x86_pmu.cntval_bits);
1837         pr_info("... generic registers:      %d\n",     x86_pmu.num_counters);
1838         pr_info("... value mask:             %016Lx\n", x86_pmu.cntval_mask);
1839         pr_info("... max period:             %016Lx\n", x86_pmu.max_period);
1840         pr_info("... fixed-purpose events:   %d\n",     x86_pmu.num_counters_fixed);
1841         pr_info("... event mask:             %016Lx\n", x86_pmu.intel_ctrl);
1842 
1843         /*
1844          * Install callbacks. Core will call them for each online
1845          * cpu.
1846          */
1847         err = cpuhp_setup_state(CPUHP_PERF_X86_PREPARE, "perf/x86:prepare",
1848                                 x86_pmu_prepare_cpu, x86_pmu_dead_cpu);
1849         if (err)
1850                 return err;
1851 
1852         err = cpuhp_setup_state(CPUHP_AP_PERF_X86_STARTING,
1853                                 "perf/x86:starting", x86_pmu_starting_cpu,
1854                                 x86_pmu_dying_cpu);
1855         if (err)
1856                 goto out;
1857 
1858         err = cpuhp_setup_state(CPUHP_AP_PERF_X86_ONLINE, "perf/x86:online",
1859                                 x86_pmu_online_cpu, NULL);
1860         if (err)
1861                 goto out1;
1862 
1863         err = perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
1864         if (err)
1865                 goto out2;
1866 
1867         return 0;
1868 
1869 out2:
1870         cpuhp_remove_state(CPUHP_AP_PERF_X86_ONLINE);
1871 out1:
1872         cpuhp_remove_state(CPUHP_AP_PERF_X86_STARTING);
1873 out:
1874         cpuhp_remove_state(CPUHP_PERF_X86_PREPARE);
1875         return err;
1876 }
1877 early_initcall(init_hw_perf_events);
1878 
1879 static inline void x86_pmu_read(struct perf_event *event)
1880 {
1881         if (x86_pmu.read)
1882                 return x86_pmu.read(event);
1883         x86_perf_event_update(event);
1884 }
1885 
1886 /*
1887  * Start group events scheduling transaction
1888  * Set the flag to make pmu::enable() not perform the
1889  * schedulability test, it will be performed at commit time
1890  *
1891  * We only support PERF_PMU_TXN_ADD transactions. Save the
1892  * transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD
1893  * transactions.
1894  */
1895 static void x86_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
1896 {
1897         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
1898 
1899         WARN_ON_ONCE(cpuc->txn_flags);          /* txn already in flight */
1900 
1901         cpuc->txn_flags = txn_flags;
1902         if (txn_flags & ~PERF_PMU_TXN_ADD)
1903                 return;
1904 
1905         perf_pmu_disable(pmu);
1906         __this_cpu_write(cpu_hw_events.n_txn, 0);
1907 }
1908 
1909 /*
1910  * Stop group events scheduling transaction
1911  * Clear the flag and pmu::enable() will perform the
1912  * schedulability test.
1913  */
1914 static void x86_pmu_cancel_txn(struct pmu *pmu)
1915 {
1916         unsigned int txn_flags;
1917         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
1918 
1919         WARN_ON_ONCE(!cpuc->txn_flags); /* no txn in flight */
1920 
1921         txn_flags = cpuc->txn_flags;
1922         cpuc->txn_flags = 0;
1923         if (txn_flags & ~PERF_PMU_TXN_ADD)
1924                 return;
1925 
1926         /*
1927          * Truncate collected array by the number of events added in this
1928          * transaction. See x86_pmu_add() and x86_pmu_*_txn().
1929          */
1930         __this_cpu_sub(cpu_hw_events.n_added, __this_cpu_read(cpu_hw_events.n_txn));
1931         __this_cpu_sub(cpu_hw_events.n_events, __this_cpu_read(cpu_hw_events.n_txn));
1932         perf_pmu_enable(pmu);
1933 }
1934 
1935 /*
1936  * Commit group events scheduling transaction
1937  * Perform the group schedulability test as a whole
1938  * Return 0 if success
1939  *
1940  * Does not cancel the transaction on failure; expects the caller to do this.
1941  */
1942 static int x86_pmu_commit_txn(struct pmu *pmu)
1943 {
1944         struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
1945         int assign[X86_PMC_IDX_MAX];
1946         int n, ret;
1947 
1948         WARN_ON_ONCE(!cpuc->txn_flags); /* no txn in flight */
1949 
1950         if (cpuc->txn_flags & ~PERF_PMU_TXN_ADD) {
1951                 cpuc->txn_flags = 0;
1952                 return 0;
1953         }
1954 
1955         n = cpuc->n_events;
1956 
1957         if (!x86_pmu_initialized())
1958                 return -EAGAIN;
1959 
1960         ret = x86_pmu.schedule_events(cpuc, n, assign);
1961         if (ret)
1962                 return ret;
1963 
1964         /*
1965          * copy new assignment, now we know it is possible
1966          * will be used by hw_perf_enable()
1967          */
1968         memcpy(cpuc->assign, assign, n*sizeof(int));
1969 
1970         cpuc->txn_flags = 0;
1971         perf_pmu_enable(pmu);
1972         return 0;
1973 }
1974 /*
1975  * a fake_cpuc is used to validate event groups. Due to
1976  * the extra reg logic, we need to also allocate a fake
1977  * per_core and per_cpu structure. Otherwise, group events
1978  * using extra reg may conflict without the kernel being
1979  * able to catch this when the last event gets added to
1980  * the group.
1981  */
1982 static void free_fake_cpuc(struct cpu_hw_events *cpuc)
1983 {
1984         intel_cpuc_finish(cpuc);
1985         kfree(cpuc);
1986 }
1987 
1988 static struct cpu_hw_events *allocate_fake_cpuc(void)
1989 {
1990         struct cpu_hw_events *cpuc;
1991         int cpu = raw_smp_processor_id();
1992 
1993         cpuc = kzalloc(sizeof(*cpuc), GFP_KERNEL);
1994         if (!cpuc)
1995                 return ERR_PTR(-ENOMEM);
1996         cpuc->is_fake = 1;
1997 
1998         if (intel_cpuc_prepare(cpuc, cpu))
1999                 goto error;
2000 
2001         return cpuc;
2002 error:
2003         free_fake_cpuc(cpuc);
2004         return ERR_PTR(-ENOMEM);
2005 }
2006 
2007 /*
2008  * validate that we can schedule this event
2009  */
2010 static int validate_event(struct perf_event *event)
2011 {
2012         struct cpu_hw_events *fake_cpuc;
2013         struct event_constraint *c;
2014         int ret = 0;
2015 
2016         fake_cpuc = allocate_fake_cpuc();
2017         if (IS_ERR(fake_cpuc))
2018                 return PTR_ERR(fake_cpuc);
2019 
2020         c = x86_pmu.get_event_constraints(fake_cpuc, 0, event);
2021 
2022         if (!c || !c->weight)
2023                 ret = -EINVAL;
2024 
2025         if (x86_pmu.put_event_constraints)
2026                 x86_pmu.put_event_constraints(fake_cpuc, event);
2027 
2028         free_fake_cpuc(fake_cpuc);
2029 
2030         return ret;
2031 }
2032 
2033 /*
2034  * validate a single event group
2035  *
2036  * validation include:
2037  *      - check events are compatible which each other
2038  *      - events do not compete for the same counter
2039  *      - number of events <= number of counters
2040  *
2041  * validation ensures the group can be loaded onto the
2042  * PMU if it was the only group available.
2043  */
2044 static int validate_group(struct perf_event *event)
2045 {
2046         struct perf_event *leader = event->group_leader;
2047         struct cpu_hw_events *fake_cpuc;
2048         int ret = -EINVAL, n;
2049 
2050         fake_cpuc = allocate_fake_cpuc();
2051         if (IS_ERR(fake_cpuc))
2052                 return PTR_ERR(fake_cpuc);
2053         /*
2054          * the event is not yet connected with its
2055          * siblings therefore we must first collect
2056          * existing siblings, then add the new event
2057          * before we can simulate the scheduling
2058          */
2059         n = collect_events(fake_cpuc, leader, true);
2060         if (n < 0)
2061                 goto out;
2062 
2063         fake_cpuc->n_events = n;
2064         n = collect_events(fake_cpuc, event, false);
2065         if (n < 0)
2066                 goto out;
2067 
2068         fake_cpuc->n_events = 0;
2069         ret = x86_pmu.schedule_events(fake_cpuc, n, NULL);
2070 
2071 out:
2072         free_fake_cpuc(fake_cpuc);
2073         return ret;
2074 }
2075 
2076 static int x86_pmu_event_init(struct perf_event *event)
2077 {
2078         struct pmu *tmp;
2079         int err;
2080 
2081         switch (event->attr.type) {
2082         case PERF_TYPE_RAW:
2083         case PERF_TYPE_HARDWARE:
2084         case PERF_TYPE_HW_CACHE:
2085                 break;
2086 
2087         default:
2088                 return -ENOENT;
2089         }
2090 
2091         err = __x86_pmu_event_init(event);
2092         if (!err) {
2093                 /*
2094                  * we temporarily connect event to its pmu
2095                  * such that validate_group() can classify
2096                  * it as an x86 event using is_x86_event()
2097                  */
2098                 tmp = event->pmu;
2099                 event->pmu = &pmu;
2100 
2101                 if (event->group_leader != event)
2102                         err = validate_group(event);
2103                 else
2104                         err = validate_event(event);
2105 
2106                 event->pmu = tmp;
2107         }
2108         if (err) {
2109                 if (event->destroy)
2110                         event->destroy(event);
2111         }
2112 
2113         if (READ_ONCE(x86_pmu.attr_rdpmc) &&
2114             !(event->hw.flags & PERF_X86_EVENT_LARGE_PEBS))
2115                 event->hw.flags |= PERF_X86_EVENT_RDPMC_ALLOWED;
2116 
2117         return err;
2118 }
2119 
2120 static void refresh_pce(void *ignored)
2121 {
2122         load_mm_cr4_irqsoff(this_cpu_read(cpu_tlbstate.loaded_mm));
2123 }
2124 
2125 static void x86_pmu_event_mapped(struct perf_event *event, struct mm_struct *mm)
2126 {
2127         if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
2128                 return;
2129 
2130         /*
2131          * This function relies on not being called concurrently in two
2132          * tasks in the same mm.  Otherwise one task could observe
2133          * perf_rdpmc_allowed > 1 and return all the way back to
2134          * userspace with CR4.PCE clear while another task is still
2135          * doing on_each_cpu_mask() to propagate CR4.PCE.
2136          *
2137          * For now, this can't happen because all callers hold mmap_sem
2138          * for write.  If this changes, we'll need a different solution.
2139          */
2140         lockdep_assert_held_write(&mm->mmap_sem);
2141 
2142         if (atomic_inc_return(&mm->context.perf_rdpmc_allowed) == 1)
2143                 on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);
2144 }
2145 
2146 static void x86_pmu_event_unmapped(struct perf_event *event, struct mm_struct *mm)
2147 {
2148 
2149         if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
2150                 return;
2151 
2152         if (atomic_dec_and_test(&mm->context.perf_rdpmc_allowed))
2153                 on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);
2154 }
2155 
2156 static int x86_pmu_event_idx(struct perf_event *event)
2157 {
2158         int idx = event->hw.idx;
2159 
2160         if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
2161                 return 0;
2162 
2163         if (x86_pmu.num_counters_fixed && idx >= INTEL_PMC_IDX_FIXED) {
2164                 idx -= INTEL_PMC_IDX_FIXED;
2165                 idx |= 1 << 30;
2166         }
2167 
2168         return idx + 1;
2169 }
2170 
2171 static ssize_t get_attr_rdpmc(struct device *cdev,
2172                               struct device_attribute *attr,
2173                               char *buf)
2174 {
2175         return snprintf(buf, 40, "%d\n", x86_pmu.attr_rdpmc);
2176 }
2177 
2178 static ssize_t set_attr_rdpmc(struct device *cdev,
2179                               struct device_attribute *attr,
2180                               const char *buf, size_t count)
2181 {
2182         unsigned long val;
2183         ssize_t ret;
2184 
2185         ret = kstrtoul(buf, 0, &val);
2186         if (ret)
2187                 return ret;
2188 
2189         if (val > 2)
2190                 return -EINVAL;
2191 
2192         if (x86_pmu.attr_rdpmc_broken)
2193                 return -ENOTSUPP;
2194 
2195         if ((val == 2) != (x86_pmu.attr_rdpmc == 2)) {
2196                 /*
2197                  * Changing into or out of always available, aka
2198                  * perf-event-bypassing mode.  This path is extremely slow,
2199                  * but only root can trigger it, so it's okay.
2200                  */
2201                 if (val == 2)
2202                         static_branch_inc(&rdpmc_always_available_key);
2203                 else
2204                         static_branch_dec(&rdpmc_always_available_key);
2205                 on_each_cpu(refresh_pce, NULL, 1);
2206         }
2207 
2208         x86_pmu.attr_rdpmc = val;
2209 
2210         return count;
2211 }
2212 
2213 static DEVICE_ATTR(rdpmc, S_IRUSR | S_IWUSR, get_attr_rdpmc, set_attr_rdpmc);
2214 
2215 static struct attribute *x86_pmu_attrs[] = {
2216         &dev_attr_rdpmc.attr,
2217         NULL,
2218 };
2219 
2220 static struct attribute_group x86_pmu_attr_group __ro_after_init = {
2221         .attrs = x86_pmu_attrs,
2222 };
2223 
2224 static ssize_t max_precise_show(struct device *cdev,
2225                                   struct device_attribute *attr,
2226                                   char *buf)
2227 {
2228         return snprintf(buf, PAGE_SIZE, "%d\n", x86_pmu_max_precise());
2229 }
2230 
2231 static DEVICE_ATTR_RO(max_precise);
2232 
2233 static struct attribute *x86_pmu_caps_attrs[] = {
2234         &dev_attr_max_precise.attr,
2235         NULL
2236 };
2237 
2238 static struct attribute_group x86_pmu_caps_group __ro_after_init = {
2239         .name = "caps",
2240         .attrs = x86_pmu_caps_attrs,
2241 };
2242 
2243 static const struct attribute_group *x86_pmu_attr_groups[] = {
2244         &x86_pmu_attr_group,
2245         &x86_pmu_format_group,
2246         &x86_pmu_events_group,
2247         &x86_pmu_caps_group,
2248         NULL,
2249 };
2250 
2251 static void x86_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
2252 {
2253         if (x86_pmu.sched_task)
2254                 x86_pmu.sched_task(ctx, sched_in);
2255 }
2256 
2257 void perf_check_microcode(void)
2258 {
2259         if (x86_pmu.check_microcode)
2260                 x86_pmu.check_microcode();
2261 }
2262 
2263 static int x86_pmu_check_period(struct perf_event *event, u64 value)
2264 {
2265         if (x86_pmu.check_period && x86_pmu.check_period(event, value))
2266                 return -EINVAL;
2267 
2268         if (value && x86_pmu.limit_period) {
2269                 if (x86_pmu.limit_period(event, value) > value)
2270                         return -EINVAL;
2271         }
2272 
2273         return 0;
2274 }
2275 
2276 static int x86_pmu_aux_output_match(struct perf_event *event)
2277 {
2278         if (!(pmu.capabilities & PERF_PMU_CAP_AUX_OUTPUT))
2279                 return 0;
2280 
2281         if (x86_pmu.aux_output_match)
2282                 return x86_pmu.aux_output_match(event);
2283 
2284         return 0;
2285 }
2286 
2287 static struct pmu pmu = {
2288         .pmu_enable             = x86_pmu_enable,
2289         .pmu_disable            = x86_pmu_disable,
2290 
2291         .attr_groups            = x86_pmu_attr_groups,
2292 
2293         .event_init             = x86_pmu_event_init,
2294 
2295         .event_mapped           = x86_pmu_event_mapped,
2296         .event_unmapped         = x86_pmu_event_unmapped,
2297 
2298         .add                    = x86_pmu_add,
2299         .del                    = x86_pmu_del,
2300         .start                  = x86_pmu_start,
2301         .stop                   = x86_pmu_stop,
2302         .read                   = x86_pmu_read,
2303 
2304         .start_txn              = x86_pmu_start_txn,
2305         .cancel_txn             = x86_pmu_cancel_txn,
2306         .commit_txn             = x86_pmu_commit_txn,
2307 
2308         .event_idx              = x86_pmu_event_idx,
2309         .sched_task             = x86_pmu_sched_task,
2310         .task_ctx_size          = sizeof(struct x86_perf_task_context),
2311         .check_period           = x86_pmu_check_period,
2312 
2313         .aux_output_match       = x86_pmu_aux_output_match,
2314 };
2315 
2316 void arch_perf_update_userpage(struct perf_event *event,
2317                                struct perf_event_mmap_page *userpg, u64 now)
2318 {
2319         struct cyc2ns_data data;
2320         u64 offset;
2321 
2322         userpg->cap_user_time = 0;
2323         userpg->cap_user_time_zero = 0;
2324         userpg->cap_user_rdpmc =
2325                 !!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED);
2326         userpg->pmc_width = x86_pmu.cntval_bits;
2327 
2328         if (!using_native_sched_clock() || !sched_clock_stable())
2329                 return;
2330 
2331         cyc2ns_read_begin(&data);
2332 
2333         offset = data.cyc2ns_offset + __sched_clock_offset;
2334 
2335         /*
2336          * Internal timekeeping for enabled/running/stopped times
2337          * is always in the local_clock domain.
2338          */
2339         userpg->cap_user_time = 1;
2340         userpg->time_mult = data.cyc2ns_mul;
2341         userpg->time_shift = data.cyc2ns_shift;
2342         userpg->time_offset = offset - now;
2343 
2344         /*
2345          * cap_user_time_zero doesn't make sense when we're using a different
2346          * time base for the records.
2347          */
2348         if (!event->attr.use_clockid) {
2349                 userpg->cap_user_time_zero = 1;
2350                 userpg->time_zero = offset;
2351         }
2352 
2353         cyc2ns_read_end();
2354 }
2355 
2356 /*
2357  * Determine whether the regs were taken from an irq/exception handler rather
2358  * than from perf_arch_fetch_caller_regs().
2359  */
2360 static bool perf_hw_regs(struct pt_regs *regs)
2361 {
2362         return regs->flags & X86_EFLAGS_FIXED;
2363 }
2364 
2365 void
2366 perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
2367 {
2368         struct unwind_state state;
2369         unsigned long addr;
2370 
2371         if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
2372                 /* TODO: We don't support guest os callchain now */
2373                 return;
2374         }
2375 
2376         if (perf_callchain_store(entry, regs->ip))
2377                 return;
2378 
2379         if (perf_hw_regs(regs))
2380                 unwind_start(&state, current, regs, NULL);
2381         else
2382                 unwind_start(&state, current, NULL, (void *)regs->sp);
2383 
2384         for (; !unwind_done(&state); unwind_next_frame(&state)) {
2385                 addr = unwind_get_return_address(&state);
2386                 if (!addr || perf_callchain_store(entry, addr))
2387                         return;
2388         }
2389 }
2390 
2391 static inline int
2392 valid_user_frame(const void __user *fp, unsigned long size)
2393 {
2394         return (__range_not_ok(fp, size, TASK_SIZE) == 0);
2395 }
2396 
2397 static unsigned long get_segment_base(unsigned int segment)
2398 {
2399         struct desc_struct *desc;
2400         unsigned int idx = segment >> 3;
2401 
2402         if ((segment & SEGMENT_TI_MASK) == SEGMENT_LDT) {
2403 #ifdef CONFIG_MODIFY_LDT_SYSCALL
2404                 struct ldt_struct *ldt;
2405 
2406                 /* IRQs are off, so this synchronizes with smp_store_release */
2407                 ldt = READ_ONCE(current->active_mm->context.ldt);
2408                 if (!ldt || idx >= ldt->nr_entries)
2409                         return 0;
2410 
2411                 desc = &ldt->entries[idx];
2412 #else
2413                 return 0;
2414 #endif
2415         } else {
2416                 if (idx >= GDT_ENTRIES)
2417                         return 0;
2418 
2419                 desc = raw_cpu_ptr(gdt_page.gdt) + idx;
2420         }
2421 
2422         return get_desc_base(desc);
2423 }
2424 
2425 #ifdef CONFIG_IA32_EMULATION
2426 
2427 #include <linux/compat.h>
2428 
2429 static inline int
2430 perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry_ctx *entry)
2431 {
2432         /* 32-bit process in 64-bit kernel. */
2433         unsigned long ss_base, cs_base;
2434         struct stack_frame_ia32 frame;
2435         const void __user *fp;
2436 
2437         if (!test_thread_flag(TIF_IA32))
2438                 return 0;
2439 
2440         cs_base = get_segment_base(regs->cs);
2441         ss_base = get_segment_base(regs->ss);
2442 
2443         fp = compat_ptr(ss_base + regs->bp);
2444         pagefault_disable();
2445         while (entry->nr < entry->max_stack) {
2446                 unsigned long bytes;
2447                 frame.next_frame     = 0;
2448                 frame.return_address = 0;
2449 
2450                 if (!valid_user_frame(fp, sizeof(frame)))
2451                         break;
2452 
2453                 bytes = __copy_from_user_nmi(&frame.next_frame, fp, 4);
2454                 if (bytes != 0)
2455                         break;
2456                 bytes = __copy_from_user_nmi(&frame.return_address, fp+4, 4);
2457                 if (bytes != 0)
2458                         break;
2459 
2460                 perf_callchain_store(entry, cs_base + frame.return_address);
2461                 fp = compat_ptr(ss_base + frame.next_frame);
2462         }
2463         pagefault_enable();
2464         return 1;
2465 }
2466 #else
2467 static inline int
2468 perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry_ctx *entry)
2469 {
2470     return 0;
2471 }
2472 #endif
2473 
2474 void
2475 perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
2476 {
2477         struct stack_frame frame;
2478         const unsigned long __user *fp;
2479 
2480         if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
2481                 /* TODO: We don't support guest os callchain now */
2482                 return;
2483         }
2484 
2485         /*
2486          * We don't know what to do with VM86 stacks.. ignore them for now.
2487          */
2488         if (regs->flags & (X86_VM_MASK | PERF_EFLAGS_VM))
2489                 return;
2490 
2491         fp = (unsigned long __user *)regs->bp;
2492 
2493         perf_callchain_store(entry, regs->ip);
2494 
2495         if (!nmi_uaccess_okay())
2496                 return;
2497 
2498         if (perf_callchain_user32(regs, entry))
2499                 return;
2500 
2501         pagefault_disable();
2502         while (entry->nr < entry->max_stack) {
2503                 unsigned long bytes;
2504 
2505                 frame.next_frame             = NULL;
2506                 frame.return_address = 0;
2507 
2508                 if (!valid_user_frame(fp, sizeof(frame)))
2509                         break;
2510 
2511                 bytes = __copy_from_user_nmi(&frame.next_frame, fp, sizeof(*fp));
2512                 if (bytes != 0)
2513                         break;
2514                 bytes = __copy_from_user_nmi(&frame.return_address, fp + 1, sizeof(*fp));
2515                 if (bytes != 0)
2516                         break;
2517 
2518                 perf_callchain_store(entry, frame.return_address);
2519                 fp = (void __user *)frame.next_frame;
2520         }
2521         pagefault_enable();
2522 }
2523 
2524 /*
2525  * Deal with code segment offsets for the various execution modes:
2526  *
2527  *   VM86 - the good olde 16 bit days, where the linear address is
2528  *          20 bits and we use regs->ip + 0x10 * regs->cs.
2529  *
2530  *   IA32 - Where we need to look at GDT/LDT segment descriptor tables
2531  *          to figure out what the 32bit base address is.
2532  *
2533  *    X32 - has TIF_X32 set, but is running in x86_64
2534  *
2535  * X86_64 - CS,DS,SS,ES are all zero based.
2536  */
2537 static unsigned long code_segment_base(struct pt_regs *regs)
2538 {
2539         /*
2540          * For IA32 we look at the GDT/LDT segment base to convert the
2541          * effective IP to a linear address.
2542          */
2543 
2544 #ifdef CONFIG_X86_32
2545         /*
2546          * If we are in VM86 mode, add the segment offset to convert to a
2547          * linear address.
2548          */
2549         if (regs->flags & X86_VM_MASK)
2550                 return 0x10 * regs->cs;
2551 
2552         if (user_mode(regs) && regs->cs != __USER_CS)
2553                 return get_segment_base(regs->cs);
2554 #else
2555         if (user_mode(regs) && !user_64bit_mode(regs) &&
2556             regs->cs != __USER32_CS)
2557                 return get_segment_base(regs->cs);
2558 #endif
2559         return 0;
2560 }
2561 
2562 unsigned long perf_instruction_pointer(struct pt_regs *regs)
2563 {
2564         if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
2565                 return perf_guest_cbs->get_guest_ip();
2566 
2567         return regs->ip + code_segment_base(regs);
2568 }
2569 
2570 unsigned long perf_misc_flags(struct pt_regs *regs)
2571 {
2572         int misc = 0;
2573 
2574         if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
2575                 if (perf_guest_cbs->is_user_mode())
2576                         misc |= PERF_RECORD_MISC_GUEST_USER;
2577                 else
2578                         misc |= PERF_RECORD_MISC_GUEST_KERNEL;
2579         } else {
2580                 if (user_mode(regs))
2581                         misc |= PERF_RECORD_MISC_USER;
2582                 else
2583                         misc |= PERF_RECORD_MISC_KERNEL;
2584         }
2585 
2586         if (regs->flags & PERF_EFLAGS_EXACT)
2587                 misc |= PERF_RECORD_MISC_EXACT_IP;
2588 
2589         return misc;
2590 }
2591 
2592 void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap)
2593 {
2594         cap->version            = x86_pmu.version;
2595         cap->num_counters_gp    = x86_pmu.num_counters;
2596         cap->num_counters_fixed = x86_pmu.num_counters_fixed;
2597         cap->bit_width_gp       = x86_pmu.cntval_bits;
2598         cap->bit_width_fixed    = x86_pmu.cntval_bits;
2599         cap->events_mask        = (unsigned int)x86_pmu.events_maskl;
2600         cap->events_mask_len    = x86_pmu.events_mask_len;
2601 }
2602 EXPORT_SYMBOL_GPL(perf_get_x86_pmu_capability);
/* [<][>][^][v][top][bottom][index][help] */
root/arch/x86/events/core.c

DEFINITIONS
