drivers/perf/arm_pmu.c

   1 #undef DEBUG
   2
   3 /*
   4  * ARM performance counter support.
   5  *
   6  * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
   7  * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
   8  *
   9  * This code is based on the sparc64 perf event code, which is in turn based
  10  * on the x86 code.
  11  */
  12 #define pr_fmt(fmt) "hw perfevents: " fmt
  13
  14 #include <linux/bitmap.h>
  15 #include <linux/cpumask.h>
  16 #include <linux/cpu_pm.h>
  17 #include <linux/export.h>
  18 #include <linux/kernel.h>
  19 #include <linux/of_device.h>
  20 #include <linux/perf/arm_pmu.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/slab.h>
  23 #include <linux/sched/clock.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/irq.h>
  26 #include <linux/irqdesc.h>
  27
  28 #include <asm/cputype.h>
  29 #include <asm/irq_regs.h>
  30
  31 static int
  32 armpmu_map_cache_event(const unsigned (*cache_map)
  33                                       [PERF_COUNT_HW_CACHE_MAX]
  34                                       [PERF_COUNT_HW_CACHE_OP_MAX]
  35                                       [PERF_COUNT_HW_CACHE_RESULT_MAX],
  36                        u64 config)
  37 {
  38         unsigned int cache_type, cache_op, cache_result, ret;
  39
  40         cache_type = (config >>  0) & 0xff;
  41         if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
  42                 return -EINVAL;
  43
  44         cache_op = (config >>  8) & 0xff;
  45         if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
  46                 return -EINVAL;
  47
  48         cache_result = (config >> 16) & 0xff;
  49         if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
  50                 return -EINVAL;
  51
  52         ret = (int)(*cache_map)[cache_type][cache_op][cache_result];
  53
  54         if (ret == CACHE_OP_UNSUPPORTED)
  55                 return -ENOENT;
  56
  57         return ret;
  58 }
  59
  60 static int
  61 armpmu_map_hw_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
  62 {
  63         int mapping;
  64
  65         if (config >= PERF_COUNT_HW_MAX)
  66                 return -EINVAL;
  67
  68         mapping = (*event_map)[config];
  69         return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping;
  70 }
  71
  72 static int
  73 armpmu_map_raw_event(u32 raw_event_mask, u64 config)
  74 {
  75         return (int)(config & raw_event_mask);
  76 }
  77
  78 int
  79 armpmu_map_event(struct perf_event *event,
  80                  const unsigned (*event_map)[PERF_COUNT_HW_MAX],
  81                  const unsigned (*cache_map)
  82                                 [PERF_COUNT_HW_CACHE_MAX]
  83                                 [PERF_COUNT_HW_CACHE_OP_MAX]
  84                                 [PERF_COUNT_HW_CACHE_RESULT_MAX],
  85                  u32 raw_event_mask)
  86 {
  87         u64 config = event->attr.config;
  88         int type = event->attr.type;
  89
  90         if (type == event->pmu->type)
  91                 return armpmu_map_raw_event(raw_event_mask, config);
  92
  93         switch (type) {
  94         case PERF_TYPE_HARDWARE:
  95                 return armpmu_map_hw_event(event_map, config);
  96         case PERF_TYPE_HW_CACHE:
  97                 return armpmu_map_cache_event(cache_map, config);
  98         case PERF_TYPE_RAW:
  99                 return armpmu_map_raw_event(raw_event_mask, config);
 100         }
 101
 102         return -ENOENT;
 103 }
 104
 105 int armpmu_event_set_period(struct perf_event *event)
 106 {
 107         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 108         struct hw_perf_event *hwc = &event->hw;
 109         s64 left = local64_read(&hwc->period_left);
 110         s64 period = hwc->sample_period;
 111         int ret = 0;
 112
 113         if (unlikely(left <= -period)) {
 114                 left = period;
 115                 local64_set(&hwc->period_left, left);
 116                 hwc->last_period = period;
 117                 ret = 1;
 118         }
 119
 120         if (unlikely(left <= 0)) {
 121                 left += period;
 122                 local64_set(&hwc->period_left, left);
 123                 hwc->last_period = period;
 124                 ret = 1;
 125         }
 126
 127         /*
 128          * Limit the maximum period to prevent the counter value
 129          * from overtaking the one we are about to program. In
 130          * effect we are reducing max_period to account for
 131          * interrupt latency (and we are being very conservative).
 132          */
 133         if (left > (armpmu->max_period >> 1))
 134                 left = armpmu->max_period >> 1;
 135
 136         local64_set(&hwc->prev_count, (u64)-left);
 137
 138         armpmu->write_counter(event, (u64)(-left) & 0xffffffff);
 139
 140         perf_event_update_userpage(event);
 141
 142         return ret;
 143 }
 144
 145 u64 armpmu_event_update(struct perf_event *event)
 146 {
 147         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 148         struct hw_perf_event *hwc = &event->hw;
 149         u64 delta, prev_raw_count, new_raw_count;
 150
 151 again:
 152         prev_raw_count = local64_read(&hwc->prev_count);
 153         new_raw_count = armpmu->read_counter(event);
 154
 155         if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
 156                              new_raw_count) != prev_raw_count)
 157                 goto again;
 158
 159         delta = (new_raw_count - prev_raw_count) & armpmu->max_period;
 160
 161         local64_add(delta, &event->count);
 162         local64_sub(delta, &hwc->period_left);
 163
 164         return new_raw_count;
 165 }
 166
 167 static void
 168 armpmu_read(struct perf_event *event)
 169 {
 170         armpmu_event_update(event);
 171 }
 172
 173 static void
 174 armpmu_stop(struct perf_event *event, int flags)
 175 {
 176         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 177         struct hw_perf_event *hwc = &event->hw;
 178
 179         /*
 180          * ARM pmu always has to update the counter, so ignore
 181          * PERF_EF_UPDATE, see comments in armpmu_start().
 182          */
 183         if (!(hwc->state & PERF_HES_STOPPED)) {
 184                 armpmu->disable(event);
 185                 armpmu_event_update(event);
 186                 hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
 187         }
 188 }
 189
 190 static void armpmu_start(struct perf_event *event, int flags)
 191 {
 192         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 193         struct hw_perf_event *hwc = &event->hw;
 194
 195         /*
 196          * ARM pmu always has to reprogram the period, so ignore
 197          * PERF_EF_RELOAD, see the comment below.
 198          */
 199         if (flags & PERF_EF_RELOAD)
 200                 WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
 201
 202         hwc->state = 0;
 203         /*
 204          * Set the period again. Some counters can't be stopped, so when we
 205          * were stopped we simply disabled the IRQ source and the counter
 206          * may have been left counting. If we don't do this step then we may
 207          * get an interrupt too soon or *way* too late if the overflow has
 208          * happened since disabling.
 209          */
 210         armpmu_event_set_period(event);
 211         armpmu->enable(event);
 212 }
 213
 214 static void
 215 armpmu_del(struct perf_event *event, int flags)
 216 {
 217         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 218         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 219         struct hw_perf_event *hwc = &event->hw;
 220         int idx = hwc->idx;
 221
 222         armpmu_stop(event, PERF_EF_UPDATE);
 223         hw_events->events[idx] = NULL;
 224         clear_bit(idx, hw_events->used_mask);
 225         if (armpmu->clear_event_idx)
 226                 armpmu->clear_event_idx(hw_events, event);
 227
 228         perf_event_update_userpage(event);
 229 }
 230
 231 static int
 232 armpmu_add(struct perf_event *event, int flags)
 233 {
 234         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 235         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 236         struct hw_perf_event *hwc = &event->hw;
 237         int idx;
 238         int err = 0;
 239
 240         /* An event following a process won't be stopped earlier */
 241         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 242                 return -ENOENT;
 243
 244         perf_pmu_disable(event->pmu);
 245
 246         /* If we don't have a space for the counter then finish early. */
 247         idx = armpmu->get_event_idx(hw_events, event);
 248         if (idx < 0) {
 249                 err = idx;
 250                 goto out;
 251         }
 252
 253         /*
 254          * If there is an event in the counter we are going to use then make
 255          * sure it is disabled.
 256          */
 257         event->hw.idx = idx;
 258         armpmu->disable(event);
 259         hw_events->events[idx] = event;
 260
 261         hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
 262         if (flags & PERF_EF_START)
 263                 armpmu_start(event, PERF_EF_RELOAD);
 264
 265         /* Propagate our changes to the userspace mapping. */
 266         perf_event_update_userpage(event);
 267
 268 out:
 269         perf_pmu_enable(event->pmu);
 270         return err;
 271 }
 272
 273 static int
 274 validate_event(struct pmu *pmu, struct pmu_hw_events *hw_events,
 275                                struct perf_event *event)
 276 {
 277         struct arm_pmu *armpmu;
 278
 279         if (is_software_event(event))
 280                 return 1;
 281
 282         /*
 283          * Reject groups spanning multiple HW PMUs (e.g. CPU + CCI). The
 284          * core perf code won't check that the pmu->ctx == leader->ctx
 285          * until after pmu->event_init(event).
 286          */
 287         if (event->pmu != pmu)
 288                 return 0;
 289
 290         if (event->state < PERF_EVENT_STATE_OFF)
 291                 return 1;
 292
 293         if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec)
 294                 return 1;
 295
 296         armpmu = to_arm_pmu(event->pmu);
 297         return armpmu->get_event_idx(hw_events, event) >= 0;
 298 }
 299
 300 static int
 301 validate_group(struct perf_event *event)
 302 {
 303         struct perf_event *sibling, *leader = event->group_leader;
 304         struct pmu_hw_events fake_pmu;
 305
 306         /*
 307          * Initialise the fake PMU. We only need to populate the
 308          * used_mask for the purposes of validation.
 309          */
 310         memset(&fake_pmu.used_mask, 0, sizeof(fake_pmu.used_mask));
 311
 312         if (!validate_event(event->pmu, &fake_pmu, leader))
 313                 return -EINVAL;
 314
 315         list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
 316                 if (!validate_event(event->pmu, &fake_pmu, sibling))
 317                         return -EINVAL;
 318         }
 319
 320         if (!validate_event(event->pmu, &fake_pmu, event))
 321                 return -EINVAL;
 322
 323         return 0;
 324 }
 325
 326 static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
 327 {
 328         struct arm_pmu *armpmu;
 329         struct platform_device *plat_device;
 330         struct arm_pmu_platdata *plat;
 331         int ret;
 332         u64 start_clock, finish_clock;
 333
 334         /*
 335          * we request the IRQ with a (possibly percpu) struct arm_pmu**, but
 336          * the handlers expect a struct arm_pmu*. The percpu_irq framework will
 337          * do any necessary shifting, we just need to perform the first
 338          * dereference.
 339          */
 340         armpmu = *(void **)dev;
 341         plat_device = armpmu->plat_device;
 342         plat = dev_get_platdata(&plat_device->dev);
 343
 344         start_clock = sched_clock();
 345         if (plat && plat->handle_irq)
 346                 ret = plat->handle_irq(irq, armpmu, armpmu->handle_irq);
 347         else
 348                 ret = armpmu->handle_irq(irq, armpmu);
 349         finish_clock = sched_clock();
 350
 351         perf_sample_event_took(finish_clock - start_clock);
 352         return ret;
 353 }
 354
 355 static void
 356 armpmu_release_hardware(struct arm_pmu *armpmu)
 357 {
 358         armpmu->free_irq(armpmu);
 359 }
 360
 361 static int
 362 armpmu_reserve_hardware(struct arm_pmu *armpmu)
 363 {
 364         int err = armpmu->request_irq(armpmu, armpmu_dispatch_irq);
 365         if (err) {
 366                 armpmu_release_hardware(armpmu);
 367                 return err;
 368         }
 369
 370         return 0;
 371 }
 372
 373 static void
 374 hw_perf_event_destroy(struct perf_event *event)
 375 {
 376         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 377         atomic_t *active_events  = &armpmu->active_events;
 378         struct mutex *pmu_reserve_mutex = &armpmu->reserve_mutex;
 379
 380         if (atomic_dec_and_mutex_lock(active_events, pmu_reserve_mutex)) {
 381                 armpmu_release_hardware(armpmu);
 382                 mutex_unlock(pmu_reserve_mutex);
 383         }
 384 }
 385
 386 static int
 387 event_requires_mode_exclusion(struct perf_event_attr *attr)
 388 {
 389         return attr->exclude_idle || attr->exclude_user ||
 390                attr->exclude_kernel || attr->exclude_hv;
 391 }
 392
 393 static int
 394 __hw_perf_event_init(struct perf_event *event)
 395 {
 396         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 397         struct hw_perf_event *hwc = &event->hw;
 398         int mapping;
 399
 400         mapping = armpmu->map_event(event);
 401
 402         if (mapping < 0) {
 403                 pr_debug("event %x:%llx not supported\n", event->attr.type,
 404                          event->attr.config);
 405                 return mapping;
 406         }
 407
 408         /*
 409          * We don't assign an index until we actually place the event onto
 410          * hardware. Use -1 to signify that we haven't decided where to put it
 411          * yet. For SMP systems, each core has it's own PMU so we can't do any
 412          * clever allocation or constraints checking at this point.
 413          */
 414         hwc->idx                = -1;
 415         hwc->config_base        = 0;
 416         hwc->config             = 0;
 417         hwc->event_base         = 0;
 418
 419         /*
 420          * Check whether we need to exclude the counter from certain modes.
 421          */
 422         if ((!armpmu->set_event_filter ||
 423              armpmu->set_event_filter(hwc, &event->attr)) &&
 424              event_requires_mode_exclusion(&event->attr)) {
 425                 pr_debug("ARM performance counters do not support "
 426                          "mode exclusion\n");
 427                 return -EOPNOTSUPP;
 428         }
 429
 430         /*
 431          * Store the event encoding into the config_base field.
 432          */
 433         hwc->config_base            |= (unsigned long)mapping;
 434
 435         if (!is_sampling_event(event)) {
 436                 /*
 437                  * For non-sampling runs, limit the sample_period to half
 438                  * of the counter width. That way, the new counter value
 439                  * is far less likely to overtake the previous one unless
 440                  * you have some serious IRQ latency issues.
 441                  */
 442                 hwc->sample_period  = armpmu->max_period >> 1;
 443                 hwc->last_period    = hwc->sample_period;
 444                 local64_set(&hwc->period_left, hwc->sample_period);
 445         }
 446
 447         if (event->group_leader != event) {
 448                 if (validate_group(event) != 0)
 449                         return -EINVAL;
 450         }
 451
 452         return 0;
 453 }
 454
 455 static int armpmu_event_init(struct perf_event *event)
 456 {
 457         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 458         int err = 0;
 459         atomic_t *active_events = &armpmu->active_events;
 460
 461         /*
 462          * Reject CPU-affine events for CPUs that are of a different class to
 463          * that which this PMU handles. Process-following events (where
 464          * event->cpu == -1) can be migrated between CPUs, and thus we have to
 465          * reject them later (in armpmu_add) if they're scheduled on a
 466          * different class of CPU.
 467          */
 468         if (event->cpu != -1 &&
 469                 !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus))
 470                 return -ENOENT;
 471
 472         /* does not support taken branch sampling */
 473         if (has_branch_stack(event))
 474                 return -EOPNOTSUPP;
 475
 476         if (armpmu->map_event(event) == -ENOENT)
 477                 return -ENOENT;
 478
 479         event->destroy = hw_perf_event_destroy;
 480
 481         if (!atomic_inc_not_zero(active_events)) {
 482                 mutex_lock(&armpmu->reserve_mutex);
 483                 if (atomic_read(active_events) == 0)
 484                         err = armpmu_reserve_hardware(armpmu);
 485
 486                 if (!err)
 487                         atomic_inc(active_events);
 488                 mutex_unlock(&armpmu->reserve_mutex);
 489         }
 490
 491         if (err)
 492                 return err;
 493
 494         err = __hw_perf_event_init(event);
 495         if (err)
 496                 hw_perf_event_destroy(event);
 497
 498         return err;
 499 }
 500
 501 static void armpmu_enable(struct pmu *pmu)
 502 {
 503         struct arm_pmu *armpmu = to_arm_pmu(pmu);
 504         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 505         int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
 506
 507         /* For task-bound events we may be called on other CPUs */
 508         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 509                 return;
 510
 511         if (enabled)
 512                 armpmu->start(armpmu);
 513 }
 514
 515 static void armpmu_disable(struct pmu *pmu)
 516 {
 517         struct arm_pmu *armpmu = to_arm_pmu(pmu);
 518
 519         /* For task-bound events we may be called on other CPUs */
 520         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 521                 return;
 522
 523         armpmu->stop(armpmu);
 524 }
 525
 526 /*
 527  * In heterogeneous systems, events are specific to a particular
 528  * microarchitecture, and aren't suitable for another. Thus, only match CPUs of
 529  * the same microarchitecture.
 530  */
 531 static int armpmu_filter_match(struct perf_event *event)
 532 {
 533         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 534         unsigned int cpu = smp_processor_id();
 535         return cpumask_test_cpu(cpu, &armpmu->supported_cpus);
 536 }
 537
 538 static ssize_t armpmu_cpumask_show(struct device *dev,
 539                                    struct device_attribute *attr, char *buf)
 540 {
 541         struct arm_pmu *armpmu = to_arm_pmu(dev_get_drvdata(dev));
 542         return cpumap_print_to_pagebuf(true, buf, &armpmu->supported_cpus);
 543 }
 544
 545 static DEVICE_ATTR(cpus, S_IRUGO, armpmu_cpumask_show, NULL);
 546
 547 static struct attribute *armpmu_common_attrs[] = {
 548         &dev_attr_cpus.attr,
 549         NULL,
 550 };
 551
 552 static struct attribute_group armpmu_common_attr_group = {
 553         .attrs = armpmu_common_attrs,
 554 };
 555
 556 static void armpmu_init(struct arm_pmu *armpmu)
 557 {
 558         atomic_set(&armpmu->active_events, 0);
 559         mutex_init(&armpmu->reserve_mutex);
 560
 561         armpmu->pmu = (struct pmu) {
 562                 .pmu_enable     = armpmu_enable,
 563                 .pmu_disable    = armpmu_disable,
 564                 .event_init     = armpmu_event_init,
 565                 .add            = armpmu_add,
 566                 .del            = armpmu_del,
 567                 .start          = armpmu_start,
 568                 .stop           = armpmu_stop,
 569                 .read           = armpmu_read,
 570                 .filter_match   = armpmu_filter_match,
 571                 .attr_groups    = armpmu->attr_groups,
 572         };
 573         armpmu->attr_groups[ARMPMU_ATTR_GROUP_COMMON] =
 574                 &armpmu_common_attr_group;
 575 }
 576
 577 /* Set at runtime when we know what CPU type we are. */
 578 static struct arm_pmu *__oprofile_cpu_pmu;
 579
 580 /*
 581  * Despite the names, these two functions are CPU-specific and are used
 582  * by the OProfile/perf code.
 583  */
 584 const char *perf_pmu_name(void)
 585 {
 586         if (!__oprofile_cpu_pmu)
 587                 return NULL;
 588
 589         return __oprofile_cpu_pmu->name;
 590 }
 591 EXPORT_SYMBOL_GPL(perf_pmu_name);
 592
 593 int perf_num_counters(void)
 594 {
 595         int max_events = 0;
 596
 597         if (__oprofile_cpu_pmu != NULL)
 598                 max_events = __oprofile_cpu_pmu->num_events;
 599
 600         return max_events;
 601 }
 602 EXPORT_SYMBOL_GPL(perf_num_counters);
 603
 604 static void cpu_pmu_enable_percpu_irq(void *data)
 605 {
 606         int irq = *(int *)data;
 607
 608         enable_percpu_irq(irq, IRQ_TYPE_NONE);
 609 }
 610
 611 static void cpu_pmu_disable_percpu_irq(void *data)
 612 {
 613         int irq = *(int *)data;
 614
 615         disable_percpu_irq(irq);
 616 }
 617
 618 static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
 619 {
 620         int cpu;
 621         struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
 622
 623         for_each_cpu(cpu, &cpu_pmu->supported_cpus) {
 624                 int irq = per_cpu(hw_events->irq, cpu);
 625                 if (!irq)
 626                         continue;
 627
 628                 if (irq_is_percpu(irq)) {
 629                         on_each_cpu_mask(&cpu_pmu->supported_cpus,
 630                                          cpu_pmu_disable_percpu_irq, &irq, 1);
 631                         free_percpu_irq(irq, &hw_events->percpu_pmu);
 632
 633                         break;
 634                 }
 635
 636                 if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
 637                         continue;
 638
 639                 free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
 640         }
 641 }
 642
 643 static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 644 {
 645         int cpu, err;
 646         struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
 647
 648         for_each_cpu(cpu, &cpu_pmu->supported_cpus) {
 649                 int irq = per_cpu(hw_events->irq, cpu);
 650                 if (!irq)
 651                         continue;
 652
 653                 if (irq_is_percpu(irq)) {
 654                         err = request_percpu_irq(irq, handler, "arm-pmu",
 655                                                  &hw_events->percpu_pmu);
 656                         if (err) {
 657                                 pr_err("unable to request IRQ%d for ARM PMU counters\n",
 658                                         irq);
 659                                 return err;
 660                         }
 661
 662                         on_each_cpu_mask(&cpu_pmu->supported_cpus,
 663                                          cpu_pmu_enable_percpu_irq, &irq, 1);
 664
 665                         break;
 666                 }
 667
 668                 /*
 669                  * If we have a single PMU interrupt that we can't shift,
 670                  * assume that we're running on a uniprocessor machine and
 671                  * continue. Otherwise, continue without this interrupt.
 672                  */
 673                 if (irq_set_affinity(irq, cpumask_of(cpu)) &&
 674                     num_possible_cpus() > 1) {
 675                         pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
 676                                 irq, cpu);
 677                         continue;
 678                 }
 679
 680                 err = request_irq(irq, handler,
 681                                   IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
 682                                   per_cpu_ptr(&hw_events->percpu_pmu, cpu));
 683                 if (err) {
 684                         pr_err("unable to request IRQ%d for ARM PMU counters\n",
 685                                 irq);
 686                         return err;
 687                 }
 688
 689                 cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);
 690         }
 691
 692         return 0;
 693 }
 694
 695 /*
 696  * PMU hardware loses all context when a CPU goes offline.
 697  * When a CPU is hotplugged back in, since some hardware registers are
 698  * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
 699  * junk values out of them.
 700  */
 701 static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
 702 {
 703         struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
 704
 705         if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
 706                 return 0;
 707         if (pmu->reset)
 708                 pmu->reset(pmu);
 709         return 0;
 710 }
 711
 712 #ifdef CONFIG_CPU_PM
 713 static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd)
 714 {
 715         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 716         struct perf_event *event;
 717         int idx;
 718
 719         for (idx = 0; idx < armpmu->num_events; idx++) {
 720                 /*
 721                  * If the counter is not used skip it, there is no
 722                  * need of stopping/restarting it.
 723                  */
 724                 if (!test_bit(idx, hw_events->used_mask))
 725                         continue;
 726
 727                 event = hw_events->events[idx];
 728
 729                 switch (cmd) {
 730                 case CPU_PM_ENTER:
 731                         /*
 732                          * Stop and update the counter
 733                          */
 734                         armpmu_stop(event, PERF_EF_UPDATE);
 735                         break;
 736                 case CPU_PM_EXIT:
 737                 case CPU_PM_ENTER_FAILED:
 738                          /*
 739                           * Restore and enable the counter.
 740                           * armpmu_start() indirectly calls
 741                           *
 742                           * perf_event_update_userpage()
 743                           *
 744                           * that requires RCU read locking to be functional,
 745                           * wrap the call within RCU_NONIDLE to make the
 746                           * RCU subsystem aware this cpu is not idle from
 747                           * an RCU perspective for the armpmu_start() call
 748                           * duration.
 749                           */
 750                         RCU_NONIDLE(armpmu_start(event, PERF_EF_RELOAD));
 751                         break;
 752                 default:
 753                         break;
 754                 }
 755         }
 756 }
 757
 758 static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
 759                              void *v)
 760 {
 761         struct arm_pmu *armpmu = container_of(b, struct arm_pmu, cpu_pm_nb);
 762         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 763         int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
 764
 765         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 766                 return NOTIFY_DONE;
 767
 768         /*
 769          * Always reset the PMU registers on power-up even if
 770          * there are no events running.
 771          */
 772         if (cmd == CPU_PM_EXIT && armpmu->reset)
 773                 armpmu->reset(armpmu);
 774
 775         if (!enabled)
 776                 return NOTIFY_OK;
 777
 778         switch (cmd) {
 779         case CPU_PM_ENTER:
 780                 armpmu->stop(armpmu);
 781                 cpu_pm_pmu_setup(armpmu, cmd);
 782                 break;
 783         case CPU_PM_EXIT:
 784                 cpu_pm_pmu_setup(armpmu, cmd);
 785         case CPU_PM_ENTER_FAILED:
 786                 armpmu->start(armpmu);
 787                 break;
 788         default:
 789                 return NOTIFY_DONE;
 790         }
 791
 792         return NOTIFY_OK;
 793 }
 794
 795 static int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu)
 796 {
 797         cpu_pmu->cpu_pm_nb.notifier_call = cpu_pm_pmu_notify;
 798         return cpu_pm_register_notifier(&cpu_pmu->cpu_pm_nb);
 799 }
 800
 801 static void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu)
 802 {
 803         cpu_pm_unregister_notifier(&cpu_pmu->cpu_pm_nb);
 804 }
 805 #else
 806 static inline int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu) { return 0; }
 807 static inline void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu) { }
 808 #endif
 809
 810 static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 811 {
 812         int err;
 813
 814         err = cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
 815                                                &cpu_pmu->node);
 816         if (err)
 817                 goto out;
 818
 819         err = cpu_pm_pmu_register(cpu_pmu);
 820         if (err)
 821                 goto out_unregister;
 822
 823         cpu_pmu->request_irq    = cpu_pmu_request_irq;
 824         cpu_pmu->free_irq       = cpu_pmu_free_irq;
 825
 826         /* Ensure the PMU has sane values out of reset. */
 827         if (cpu_pmu->reset)
 828                 on_each_cpu_mask(&cpu_pmu->supported_cpus, cpu_pmu->reset,
 829                          cpu_pmu, 1);
 830
 831         /*
 832          * This is a CPU PMU potentially in a heterogeneous configuration (e.g.
 833          * big.LITTLE). This is not an uncore PMU, and we have taken ctx
 834          * sharing into account (e.g. with our pmu::filter_match callback and
 835          * pmu::event_init group validation).
 836          */
 837         cpu_pmu->pmu.capabilities |= PERF_PMU_CAP_HETEROGENEOUS_CPUS;
 838
 839         return 0;
 840
 841 out_unregister:
 842         cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
 843                                             &cpu_pmu->node);
 844 out:
 845         return err;
 846 }
 847
 848 static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
 849 {
 850         cpu_pm_pmu_unregister(cpu_pmu);
 851         cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
 852                                             &cpu_pmu->node);
 853 }
 854
 855 /*
 856  * CPU PMU identification and probing.
 857  */
 858 static int probe_current_pmu(struct arm_pmu *pmu,
 859                              const struct pmu_probe_info *info)
 860 {
 861         int cpu = get_cpu();
 862         unsigned int cpuid = read_cpuid_id();
 863         int ret = -ENODEV;
 864
 865         pr_info("probing PMU on CPU %d\n", cpu);
 866
 867         for (; info->init != NULL; info++) {
 868                 if ((cpuid & info->mask) != info->cpuid)
 869                         continue;
 870                 ret = info->init(pmu);
 871                 break;
 872         }
 873
 874         put_cpu();
 875         return ret;
 876 }
 877
 878 static int pmu_parse_percpu_irq(struct arm_pmu *pmu, int irq)
 879 {
 880         int cpu, ret;
 881         struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
 882
 883         ret = irq_get_percpu_devid_partition(irq, &pmu->supported_cpus);
 884         if (ret)
 885                 return ret;
 886
 887         for_each_cpu(cpu, &pmu->supported_cpus)
 888                 per_cpu(hw_events->irq, cpu) = irq;
 889
 890         return 0;
 891 }
 892
 893 static bool pmu_has_irq_affinity(struct device_node *node)
 894 {
 895         return !!of_find_property(node, "interrupt-affinity", NULL);
 896 }
 897
 898 static int pmu_parse_irq_affinity(struct device_node *node, int i)
 899 {
 900         struct device_node *dn;
 901         int cpu;
 902
 903         /*
 904          * If we don't have an interrupt-affinity property, we guess irq
 905          * affinity matches our logical CPU order, as we used to assume.
 906          * This is fragile, so we'll warn in pmu_parse_irqs().
 907          */
 908         if (!pmu_has_irq_affinity(node))
 909                 return i;
 910
 911         dn = of_parse_phandle(node, "interrupt-affinity", i);
 912         if (!dn) {
 913                 pr_warn("failed to parse interrupt-affinity[%d] for %s\n",
 914                         i, node->name);
 915                 return -EINVAL;
 916         }
 917
 918         /* Now look up the logical CPU number */
 919         for_each_possible_cpu(cpu) {
 920                 struct device_node *cpu_dn;
 921
 922                 cpu_dn = of_cpu_device_node_get(cpu);
 923                 of_node_put(cpu_dn);
 924
 925                 if (dn == cpu_dn)
 926                         break;
 927         }
 928
 929         if (cpu >= nr_cpu_ids) {
 930                 pr_warn("failed to find logical CPU for %s\n", dn->name);
 931         }
 932
 933         of_node_put(dn);
 934
 935         return cpu;
 936 }
 937
 938 static int pmu_parse_irqs(struct arm_pmu *pmu)
 939 {
 940         int i = 0, irqs;
 941         struct platform_device *pdev = pmu->plat_device;
 942         struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
 943
 944         irqs = platform_irq_count(pdev);
 945         if (irqs < 0) {
 946                 pr_err("unable to count PMU IRQs\n");
 947                 return irqs;
 948         }
 949
 950         /*
 951          * In this case we have no idea which CPUs are covered by the PMU.
 952          * To match our prior behaviour, we assume all CPUs in this case.
 953          */
 954         if (irqs == 0) {
 955                 pr_warn("no irqs for PMU, sampling events not supported\n");
 956                 pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 957                 cpumask_setall(&pmu->supported_cpus);
 958                 return 0;
 959         }
 960
 961         if (irqs == 1) {
 962                 int irq = platform_get_irq(pdev, 0);
 963                 if (irq && irq_is_percpu(irq))
 964                         return pmu_parse_percpu_irq(pmu, irq);
 965         }
 966
 967         if (!pmu_has_irq_affinity(pdev->dev.of_node)) {
 968                 pr_warn("no interrupt-affinity property for %s, guessing.\n",
 969                         of_node_full_name(pdev->dev.of_node));
 970         }
 971
 972         /*
 973          * Some platforms have all PMU IRQs OR'd into a single IRQ, with a
 974          * special platdata function that attempts to demux them.
 975          */
 976         if (dev_get_platdata(&pdev->dev))
 977                 cpumask_setall(&pmu->supported_cpus);
 978
 979         for (i = 0; i < irqs; i++) {
 980                 int cpu, irq;
 981
 982                 irq = platform_get_irq(pdev, i);
 983                 if (WARN_ON(irq <= 0))
 984                         continue;
 985
 986                 if (irq_is_percpu(irq)) {
 987                         pr_warn("multiple PPIs or mismatched SPI/PPI detected\n");
 988                         return -EINVAL;
 989                 }
 990
 991                 cpu = pmu_parse_irq_affinity(pdev->dev.of_node, i);
 992                 if (cpu < 0)
 993                         return cpu;
 994                 if (cpu >= nr_cpu_ids)
 995                         continue;
 996
 997                 if (per_cpu(hw_events->irq, cpu)) {
 998                         pr_warn("multiple PMU IRQs for the same CPU detected\n");
 999                         return -EINVAL;
1000                 }
1001
1002                 per_cpu(hw_events->irq, cpu) = irq;
1003                 cpumask_set_cpu(cpu, &pmu->supported_cpus);
1004         }
1005
1006         return 0;
1007 }
1008
1009 static struct arm_pmu *armpmu_alloc(void)
1010 {
1011         struct arm_pmu *pmu;
1012         int cpu;
1013
1014         pmu = kzalloc(sizeof(*pmu), GFP_KERNEL);
1015         if (!pmu) {
1016                 pr_info("failed to allocate PMU device!\n");
1017                 goto out;
1018         }
1019
1020         pmu->hw_events = alloc_percpu(struct pmu_hw_events);
1021         if (!pmu->hw_events) {
1022                 pr_info("failed to allocate per-cpu PMU data.\n");
1023                 goto out_free_pmu;
1024         }
1025
1026         for_each_possible_cpu(cpu) {
1027                 struct pmu_hw_events *events;
1028
1029                 events = per_cpu_ptr(pmu->hw_events, cpu);
1030                 raw_spin_lock_init(&events->pmu_lock);
1031                 events->percpu_pmu = pmu;
1032         }
1033
1034         return pmu;
1035
1036 out_free_pmu:
1037         kfree(pmu);
1038 out:
1039         return NULL;
1040 }
1041
1042 static void armpmu_free(struct arm_pmu *pmu)
1043 {
1044         free_percpu(pmu->hw_events);
1045         kfree(pmu);
1046 }
1047
1048 int arm_pmu_device_probe(struct platform_device *pdev,
1049                          const struct of_device_id *of_table,
1050                          const struct pmu_probe_info *probe_table)
1051 {
1052         const struct of_device_id *of_id;
1053         const int (*init_fn)(struct arm_pmu *);
1054         struct device_node *node = pdev->dev.of_node;
1055         struct arm_pmu *pmu;
1056         int ret = -ENODEV;
1057
1058         pmu = armpmu_alloc();
1059         if (!pmu)
1060                 return -ENOMEM;
1061
1062         armpmu_init(pmu);
1063
1064         pmu->plat_device = pdev;
1065
1066         ret = pmu_parse_irqs(pmu);
1067         if (ret)
1068                 goto out_free;
1069
1070         if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
1071                 init_fn = of_id->data;
1072
1073                 pmu->secure_access = of_property_read_bool(pdev->dev.of_node,
1074                                                            "secure-reg-access");
1075
1076                 /* arm64 systems boot only as non-secure */
1077                 if (IS_ENABLED(CONFIG_ARM64) && pmu->secure_access) {
1078                         pr_warn("ignoring \"secure-reg-access\" property for arm64\n");
1079                         pmu->secure_access = false;
1080                 }
1081
1082                 ret = init_fn(pmu);
1083         } else if (probe_table) {
1084                 cpumask_setall(&pmu->supported_cpus);
1085                 ret = probe_current_pmu(pmu, probe_table);
1086         }
1087
1088         if (ret) {
1089                 pr_info("%s: failed to probe PMU!\n", of_node_full_name(node));
1090                 goto out_free;
1091         }
1092
1093
1094         ret = cpu_pmu_init(pmu);
1095         if (ret)
1096                 goto out_free;
1097
1098         ret = perf_pmu_register(&pmu->pmu, pmu->name, -1);
1099         if (ret)
1100                 goto out_destroy;
1101
1102         if (!__oprofile_cpu_pmu)
1103                 __oprofile_cpu_pmu = pmu;
1104
1105         pr_info("enabled with %s PMU driver, %d counters available\n",
1106                         pmu->name, pmu->num_events);
1107
1108         return 0;
1109
1110 out_destroy:
1111         cpu_pmu_destroy(pmu);
1112 out_free:
1113         pr_info("%s: failed to register PMU devices!\n",
1114                 of_node_full_name(node));
1115         armpmu_free(pmu);
1116         return ret;
1117 }
1118
1119 static int arm_pmu_hp_init(void)
1120 {
1121         int ret;
1122
1123         ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_STARTING,
1124                                       "perf/arm/pmu:starting",
1125                                       arm_perf_starting_cpu, NULL);
1126         if (ret)
1127                 pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n",
1128                        ret);
1129         return ret;
1130 }
1131 subsys_initcall(arm_pmu_hp_init);