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/perf/arm_pmu.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/slab.h>
  22 #include <linux/sched/clock.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/irq.h>
  25 #include <linux/irqdesc.h>
  26
  27 #include <asm/irq_regs.h>
  28
  29 static int
  30 armpmu_map_cache_event(const unsigned (*cache_map)
  31                                       [PERF_COUNT_HW_CACHE_MAX]
  32                                       [PERF_COUNT_HW_CACHE_OP_MAX]
  33                                       [PERF_COUNT_HW_CACHE_RESULT_MAX],
  34                        u64 config)
  35 {
  36         unsigned int cache_type, cache_op, cache_result, ret;
  37
  38         cache_type = (config >>  0) & 0xff;
  39         if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
  40                 return -EINVAL;
  41
  42         cache_op = (config >>  8) & 0xff;
  43         if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
  44                 return -EINVAL;
  45
  46         cache_result = (config >> 16) & 0xff;
  47         if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
  48                 return -EINVAL;
  49
  50         if (!cache_map)
  51                 return -ENOENT;
  52
  53         ret = (int)(*cache_map)[cache_type][cache_op][cache_result];
  54
  55         if (ret == CACHE_OP_UNSUPPORTED)
  56                 return -ENOENT;
  57
  58         return ret;
  59 }
  60
  61 static int
  62 armpmu_map_hw_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
  63 {
  64         int mapping;
  65
  66         if (config >= PERF_COUNT_HW_MAX)
  67                 return -EINVAL;
  68
  69         if (!event_map)
  70                 return -ENOENT;
  71
  72         mapping = (*event_map)[config];
  73         return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping;
  74 }
  75
  76 static int
  77 armpmu_map_raw_event(u32 raw_event_mask, u64 config)
  78 {
  79         return (int)(config & raw_event_mask);
  80 }
  81
  82 int
  83 armpmu_map_event(struct perf_event *event,
  84                  const unsigned (*event_map)[PERF_COUNT_HW_MAX],
  85                  const unsigned (*cache_map)
  86                                 [PERF_COUNT_HW_CACHE_MAX]
  87                                 [PERF_COUNT_HW_CACHE_OP_MAX]
  88                                 [PERF_COUNT_HW_CACHE_RESULT_MAX],
  89                  u32 raw_event_mask)
  90 {
  91         u64 config = event->attr.config;
  92         int type = event->attr.type;
  93
  94         if (type == event->pmu->type)
  95                 return armpmu_map_raw_event(raw_event_mask, config);
  96
  97         switch (type) {
  98         case PERF_TYPE_HARDWARE:
  99                 return armpmu_map_hw_event(event_map, config);
 100         case PERF_TYPE_HW_CACHE:
 101                 return armpmu_map_cache_event(cache_map, config);
 102         case PERF_TYPE_RAW:
 103                 return armpmu_map_raw_event(raw_event_mask, config);
 104         }
 105
 106         return -ENOENT;
 107 }
 108
 109 int armpmu_event_set_period(struct perf_event *event)
 110 {
 111         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 112         struct hw_perf_event *hwc = &event->hw;
 113         s64 left = local64_read(&hwc->period_left);
 114         s64 period = hwc->sample_period;
 115         int ret = 0;
 116
 117         if (unlikely(left <= -period)) {
 118                 left = period;
 119                 local64_set(&hwc->period_left, left);
 120                 hwc->last_period = period;
 121                 ret = 1;
 122         }
 123
 124         if (unlikely(left <= 0)) {
 125                 left += period;
 126                 local64_set(&hwc->period_left, left);
 127                 hwc->last_period = period;
 128                 ret = 1;
 129         }
 130
 131         /*
 132          * Limit the maximum period to prevent the counter value
 133          * from overtaking the one we are about to program. In
 134          * effect we are reducing max_period to account for
 135          * interrupt latency (and we are being very conservative).
 136          */
 137         if (left > (armpmu->max_period >> 1))
 138                 left = armpmu->max_period >> 1;
 139
 140         local64_set(&hwc->prev_count, (u64)-left);
 141
 142         armpmu->write_counter(event, (u64)(-left) & 0xffffffff);
 143
 144         perf_event_update_userpage(event);
 145
 146         return ret;
 147 }
 148
 149 u64 armpmu_event_update(struct perf_event *event)
 150 {
 151         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 152         struct hw_perf_event *hwc = &event->hw;
 153         u64 delta, prev_raw_count, new_raw_count;
 154
 155 again:
 156         prev_raw_count = local64_read(&hwc->prev_count);
 157         new_raw_count = armpmu->read_counter(event);
 158
 159         if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
 160                              new_raw_count) != prev_raw_count)
 161                 goto again;
 162
 163         delta = (new_raw_count - prev_raw_count) & armpmu->max_period;
 164
 165         local64_add(delta, &event->count);
 166         local64_sub(delta, &hwc->period_left);
 167
 168         return new_raw_count;
 169 }
 170
 171 static void
 172 armpmu_read(struct perf_event *event)
 173 {
 174         armpmu_event_update(event);
 175 }
 176
 177 static void
 178 armpmu_stop(struct perf_event *event, int flags)
 179 {
 180         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 181         struct hw_perf_event *hwc = &event->hw;
 182
 183         /*
 184          * ARM pmu always has to update the counter, so ignore
 185          * PERF_EF_UPDATE, see comments in armpmu_start().
 186          */
 187         if (!(hwc->state & PERF_HES_STOPPED)) {
 188                 armpmu->disable(event);
 189                 armpmu_event_update(event);
 190                 hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
 191         }
 192 }
 193
 194 static void armpmu_start(struct perf_event *event, int flags)
 195 {
 196         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 197         struct hw_perf_event *hwc = &event->hw;
 198
 199         /*
 200          * ARM pmu always has to reprogram the period, so ignore
 201          * PERF_EF_RELOAD, see the comment below.
 202          */
 203         if (flags & PERF_EF_RELOAD)
 204                 WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
 205
 206         hwc->state = 0;
 207         /*
 208          * Set the period again. Some counters can't be stopped, so when we
 209          * were stopped we simply disabled the IRQ source and the counter
 210          * may have been left counting. If we don't do this step then we may
 211          * get an interrupt too soon or *way* too late if the overflow has
 212          * happened since disabling.
 213          */
 214         armpmu_event_set_period(event);
 215         armpmu->enable(event);
 216 }
 217
 218 static void
 219 armpmu_del(struct perf_event *event, int flags)
 220 {
 221         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 222         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 223         struct hw_perf_event *hwc = &event->hw;
 224         int idx = hwc->idx;
 225
 226         armpmu_stop(event, PERF_EF_UPDATE);
 227         hw_events->events[idx] = NULL;
 228         clear_bit(idx, hw_events->used_mask);
 229         if (armpmu->clear_event_idx)
 230                 armpmu->clear_event_idx(hw_events, event);
 231
 232         perf_event_update_userpage(event);
 233 }
 234
 235 static int
 236 armpmu_add(struct perf_event *event, int flags)
 237 {
 238         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 239         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 240         struct hw_perf_event *hwc = &event->hw;
 241         int idx;
 242
 243         /* An event following a process won't be stopped earlier */
 244         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 245                 return -ENOENT;
 246
 247         /* If we don't have a space for the counter then finish early. */
 248         idx = armpmu->get_event_idx(hw_events, event);
 249         if (idx < 0)
 250                 return idx;
 251
 252         /*
 253          * If there is an event in the counter we are going to use then make
 254          * sure it is disabled.
 255          */
 256         event->hw.idx = idx;
 257         armpmu->disable(event);
 258         hw_events->events[idx] = event;
 259
 260         hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
 261         if (flags & PERF_EF_START)
 262                 armpmu_start(event, PERF_EF_RELOAD);
 263
 264         /* Propagate our changes to the userspace mapping. */
 265         perf_event_update_userpage(event);
 266
 267         return 0;
 268 }
 269
 270 static int
 271 validate_event(struct pmu *pmu, struct pmu_hw_events *hw_events,
 272                                struct perf_event *event)
 273 {
 274         struct arm_pmu *armpmu;
 275
 276         if (is_software_event(event))
 277                 return 1;
 278
 279         /*
 280          * Reject groups spanning multiple HW PMUs (e.g. CPU + CCI). The
 281          * core perf code won't check that the pmu->ctx == leader->ctx
 282          * until after pmu->event_init(event).
 283          */
 284         if (event->pmu != pmu)
 285                 return 0;
 286
 287         if (event->state < PERF_EVENT_STATE_OFF)
 288                 return 1;
 289
 290         if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec)
 291                 return 1;
 292
 293         armpmu = to_arm_pmu(event->pmu);
 294         return armpmu->get_event_idx(hw_events, event) >= 0;
 295 }
 296
 297 static int
 298 validate_group(struct perf_event *event)
 299 {
 300         struct perf_event *sibling, *leader = event->group_leader;
 301         struct pmu_hw_events fake_pmu;
 302
 303         /*
 304          * Initialise the fake PMU. We only need to populate the
 305          * used_mask for the purposes of validation.
 306          */
 307         memset(&fake_pmu.used_mask, 0, sizeof(fake_pmu.used_mask));
 308
 309         if (!validate_event(event->pmu, &fake_pmu, leader))
 310                 return -EINVAL;
 311
 312         list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
 313                 if (!validate_event(event->pmu, &fake_pmu, sibling))
 314                         return -EINVAL;
 315         }
 316
 317         if (!validate_event(event->pmu, &fake_pmu, event))
 318                 return -EINVAL;
 319
 320         return 0;
 321 }
 322
 323 static struct arm_pmu_platdata *armpmu_get_platdata(struct arm_pmu *armpmu)
 324 {
 325         struct platform_device *pdev = armpmu->plat_device;
 326
 327         return pdev ? dev_get_platdata(&pdev->dev) : NULL;
 328 }
 329
 330 static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
 331 {
 332         struct arm_pmu *armpmu;
 333         struct arm_pmu_platdata *plat;
 334         int ret;
 335         u64 start_clock, finish_clock;
 336
 337         /*
 338          * we request the IRQ with a (possibly percpu) struct arm_pmu**, but
 339          * the handlers expect a struct arm_pmu*. The percpu_irq framework will
 340          * do any necessary shifting, we just need to perform the first
 341          * dereference.
 342          */
 343         armpmu = *(void **)dev;
 344
 345         plat = armpmu_get_platdata(armpmu);
 346
 347         start_clock = sched_clock();
 348         if (plat && plat->handle_irq)
 349                 ret = plat->handle_irq(irq, armpmu, armpmu->handle_irq);
 350         else
 351                 ret = armpmu->handle_irq(irq, armpmu);
 352         finish_clock = sched_clock();
 353
 354         perf_sample_event_took(finish_clock - start_clock);
 355         return ret;
 356 }
 357
 358 static int
 359 event_requires_mode_exclusion(struct perf_event_attr *attr)
 360 {
 361         return attr->exclude_idle || attr->exclude_user ||
 362                attr->exclude_kernel || attr->exclude_hv;
 363 }
 364
 365 static int
 366 __hw_perf_event_init(struct perf_event *event)
 367 {
 368         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 369         struct hw_perf_event *hwc = &event->hw;
 370         int mapping;
 371
 372         mapping = armpmu->map_event(event);
 373
 374         if (mapping < 0) {
 375                 pr_debug("event %x:%llx not supported\n", event->attr.type,
 376                          event->attr.config);
 377                 return mapping;
 378         }
 379
 380         /*
 381          * We don't assign an index until we actually place the event onto
 382          * hardware. Use -1 to signify that we haven't decided where to put it
 383          * yet. For SMP systems, each core has it's own PMU so we can't do any
 384          * clever allocation or constraints checking at this point.
 385          */
 386         hwc->idx                = -1;
 387         hwc->config_base        = 0;
 388         hwc->config             = 0;
 389         hwc->event_base         = 0;
 390
 391         /*
 392          * Check whether we need to exclude the counter from certain modes.
 393          */
 394         if ((!armpmu->set_event_filter ||
 395              armpmu->set_event_filter(hwc, &event->attr)) &&
 396              event_requires_mode_exclusion(&event->attr)) {
 397                 pr_debug("ARM performance counters do not support "
 398                          "mode exclusion\n");
 399                 return -EOPNOTSUPP;
 400         }
 401
 402         /*
 403          * Store the event encoding into the config_base field.
 404          */
 405         hwc->config_base            |= (unsigned long)mapping;
 406
 407         if (!is_sampling_event(event)) {
 408                 /*
 409                  * For non-sampling runs, limit the sample_period to half
 410                  * of the counter width. That way, the new counter value
 411                  * is far less likely to overtake the previous one unless
 412                  * you have some serious IRQ latency issues.
 413                  */
 414                 hwc->sample_period  = armpmu->max_period >> 1;
 415                 hwc->last_period    = hwc->sample_period;
 416                 local64_set(&hwc->period_left, hwc->sample_period);
 417         }
 418
 419         if (event->group_leader != event) {
 420                 if (validate_group(event) != 0)
 421                         return -EINVAL;
 422         }
 423
 424         return 0;
 425 }
 426
 427 static int armpmu_event_init(struct perf_event *event)
 428 {
 429         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 430
 431         /*
 432          * Reject CPU-affine events for CPUs that are of a different class to
 433          * that which this PMU handles. Process-following events (where
 434          * event->cpu == -1) can be migrated between CPUs, and thus we have to
 435          * reject them later (in armpmu_add) if they're scheduled on a
 436          * different class of CPU.
 437          */
 438         if (event->cpu != -1 &&
 439                 !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus))
 440                 return -ENOENT;
 441
 442         /* does not support taken branch sampling */
 443         if (has_branch_stack(event))
 444                 return -EOPNOTSUPP;
 445
 446         if (armpmu->map_event(event) == -ENOENT)
 447                 return -ENOENT;
 448
 449         return __hw_perf_event_init(event);
 450 }
 451
 452 static void armpmu_enable(struct pmu *pmu)
 453 {
 454         struct arm_pmu *armpmu = to_arm_pmu(pmu);
 455         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 456         int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
 457
 458         /* For task-bound events we may be called on other CPUs */
 459         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 460                 return;
 461
 462         if (enabled)
 463                 armpmu->start(armpmu);
 464 }
 465
 466 static void armpmu_disable(struct pmu *pmu)
 467 {
 468         struct arm_pmu *armpmu = to_arm_pmu(pmu);
 469
 470         /* For task-bound events we may be called on other CPUs */
 471         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 472                 return;
 473
 474         armpmu->stop(armpmu);
 475 }
 476
 477 /*
 478  * In heterogeneous systems, events are specific to a particular
 479  * microarchitecture, and aren't suitable for another. Thus, only match CPUs of
 480  * the same microarchitecture.
 481  */
 482 static int armpmu_filter_match(struct perf_event *event)
 483 {
 484         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 485         unsigned int cpu = smp_processor_id();
 486         return cpumask_test_cpu(cpu, &armpmu->supported_cpus);
 487 }
 488
 489 static ssize_t armpmu_cpumask_show(struct device *dev,
 490                                    struct device_attribute *attr, char *buf)
 491 {
 492         struct arm_pmu *armpmu = to_arm_pmu(dev_get_drvdata(dev));
 493         return cpumap_print_to_pagebuf(true, buf, &armpmu->supported_cpus);
 494 }
 495
 496 static DEVICE_ATTR(cpus, S_IRUGO, armpmu_cpumask_show, NULL);
 497
 498 static struct attribute *armpmu_common_attrs[] = {
 499         &dev_attr_cpus.attr,
 500         NULL,
 501 };
 502
 503 static struct attribute_group armpmu_common_attr_group = {
 504         .attrs = armpmu_common_attrs,
 505 };
 506
 507 /* Set at runtime when we know what CPU type we are. */
 508 static struct arm_pmu *__oprofile_cpu_pmu;
 509
 510 /*
 511  * Despite the names, these two functions are CPU-specific and are used
 512  * by the OProfile/perf code.
 513  */
 514 const char *perf_pmu_name(void)
 515 {
 516         if (!__oprofile_cpu_pmu)
 517                 return NULL;
 518
 519         return __oprofile_cpu_pmu->name;
 520 }
 521 EXPORT_SYMBOL_GPL(perf_pmu_name);
 522
 523 int perf_num_counters(void)
 524 {
 525         int max_events = 0;
 526
 527         if (__oprofile_cpu_pmu != NULL)
 528                 max_events = __oprofile_cpu_pmu->num_events;
 529
 530         return max_events;
 531 }
 532 EXPORT_SYMBOL_GPL(perf_num_counters);
 533
 534 void armpmu_free_irq(struct arm_pmu *armpmu, int cpu)
 535 {
 536         struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
 537         int irq = per_cpu(hw_events->irq, cpu);
 538
 539         if (!cpumask_test_and_clear_cpu(cpu, &armpmu->active_irqs))
 540                 return;
 541
 542         if (irq_is_percpu(irq)) {
 543                 free_percpu_irq(irq, &hw_events->percpu_pmu);
 544                 cpumask_clear(&armpmu->active_irqs);
 545                 return;
 546         }
 547
 548         free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
 549 }
 550
 551 void armpmu_free_irqs(struct arm_pmu *armpmu)
 552 {
 553         int cpu;
 554
 555         for_each_cpu(cpu, &armpmu->supported_cpus)
 556                 armpmu_free_irq(armpmu, cpu);
 557 }
 558
 559 int armpmu_request_irq(struct arm_pmu *armpmu, int cpu)
 560 {
 561         int err = 0;
 562         struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
 563         const irq_handler_t handler = armpmu_dispatch_irq;
 564         int irq = per_cpu(hw_events->irq, cpu);
 565         if (!irq)
 566                 return 0;
 567
 568         if (irq_is_percpu(irq) && cpumask_empty(&armpmu->active_irqs)) {
 569                 err = request_percpu_irq(irq, handler, "arm-pmu",
 570                                          &hw_events->percpu_pmu);
 571         } else if (irq_is_percpu(irq)) {
 572                 int other_cpu = cpumask_first(&armpmu->active_irqs);
 573                 int other_irq = per_cpu(hw_events->irq, other_cpu);
 574
 575                 if (irq != other_irq) {
 576                         pr_warn("mismatched PPIs detected.\n");
 577                         err = -EINVAL;
 578                         goto err_out;
 579                 }
 580         } else {
 581                 struct arm_pmu_platdata *platdata = armpmu_get_platdata(armpmu);
 582                 unsigned long irq_flags;
 583
 584                 err = irq_force_affinity(irq, cpumask_of(cpu));
 585
 586                 if (err && num_possible_cpus() > 1) {
 587                         pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
 588                                 irq, cpu);
 589                         goto err_out;
 590                 }
 591
 592                 if (platdata && platdata->irq_flags) {
 593                         irq_flags = platdata->irq_flags;
 594                 } else {
 595                         irq_flags = IRQF_PERCPU |
 596                                     IRQF_NOBALANCING |
 597                                     IRQF_NO_THREAD;
 598                 }
 599
 600                 err = request_irq(irq, handler, irq_flags, "arm-pmu",
 601                                   per_cpu_ptr(&hw_events->percpu_pmu, cpu));
 602         }
 603
 604         if (err)
 605                 goto err_out;
 606
 607         cpumask_set_cpu(cpu, &armpmu->active_irqs);
 608         return 0;
 609
 610 err_out:
 611         pr_err("unable to request IRQ%d for ARM PMU counters\n", irq);
 612         return err;
 613 }
 614
 615 int armpmu_request_irqs(struct arm_pmu *armpmu)
 616 {
 617         int cpu, err;
 618
 619         for_each_cpu(cpu, &armpmu->supported_cpus) {
 620                 err = armpmu_request_irq(armpmu, cpu);
 621                 if (err)
 622                         break;
 623         }
 624
 625         return err;
 626 }
 627
 628 static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu)
 629 {
 630         struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
 631         return per_cpu(hw_events->irq, cpu);
 632 }
 633
 634 /*
 635  * PMU hardware loses all context when a CPU goes offline.
 636  * When a CPU is hotplugged back in, since some hardware registers are
 637  * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
 638  * junk values out of them.
 639  */
 640 static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
 641 {
 642         struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
 643         int irq;
 644
 645         if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
 646                 return 0;
 647         if (pmu->reset)
 648                 pmu->reset(pmu);
 649
 650         irq = armpmu_get_cpu_irq(pmu, cpu);
 651         if (irq) {
 652                 if (irq_is_percpu(irq)) {
 653                         enable_percpu_irq(irq, IRQ_TYPE_NONE);
 654                         return 0;
 655                 }
 656         }
 657
 658         return 0;
 659 }
 660
 661 static int arm_perf_teardown_cpu(unsigned int cpu, struct hlist_node *node)
 662 {
 663         struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
 664         int irq;
 665
 666         if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
 667                 return 0;
 668
 669         irq = armpmu_get_cpu_irq(pmu, cpu);
 670         if (irq && irq_is_percpu(irq))
 671                 disable_percpu_irq(irq);
 672
 673         return 0;
 674 }
 675
 676 #ifdef CONFIG_CPU_PM
 677 static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd)
 678 {
 679         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 680         struct perf_event *event;
 681         int idx;
 682
 683         for (idx = 0; idx < armpmu->num_events; idx++) {
 684                 /*
 685                  * If the counter is not used skip it, there is no
 686                  * need of stopping/restarting it.
 687                  */
 688                 if (!test_bit(idx, hw_events->used_mask))
 689                         continue;
 690
 691                 event = hw_events->events[idx];
 692
 693                 switch (cmd) {
 694                 case CPU_PM_ENTER:
 695                         /*
 696                          * Stop and update the counter
 697                          */
 698                         armpmu_stop(event, PERF_EF_UPDATE);
 699                         break;
 700                 case CPU_PM_EXIT:
 701                 case CPU_PM_ENTER_FAILED:
 702                          /*
 703                           * Restore and enable the counter.
 704                           * armpmu_start() indirectly calls
 705                           *
 706                           * perf_event_update_userpage()
 707                           *
 708                           * that requires RCU read locking to be functional,
 709                           * wrap the call within RCU_NONIDLE to make the
 710                           * RCU subsystem aware this cpu is not idle from
 711                           * an RCU perspective for the armpmu_start() call
 712                           * duration.
 713                           */
 714                         RCU_NONIDLE(armpmu_start(event, PERF_EF_RELOAD));
 715                         break;
 716                 default:
 717                         break;
 718                 }
 719         }
 720 }
 721
 722 static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
 723                              void *v)
 724 {
 725         struct arm_pmu *armpmu = container_of(b, struct arm_pmu, cpu_pm_nb);
 726         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 727         int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
 728
 729         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 730                 return NOTIFY_DONE;
 731
 732         /*
 733          * Always reset the PMU registers on power-up even if
 734          * there are no events running.
 735          */
 736         if (cmd == CPU_PM_EXIT && armpmu->reset)
 737                 armpmu->reset(armpmu);
 738
 739         if (!enabled)
 740                 return NOTIFY_OK;
 741
 742         switch (cmd) {
 743         case CPU_PM_ENTER:
 744                 armpmu->stop(armpmu);
 745                 cpu_pm_pmu_setup(armpmu, cmd);
 746                 break;
 747         case CPU_PM_EXIT:
 748                 cpu_pm_pmu_setup(armpmu, cmd);
 749         case CPU_PM_ENTER_FAILED:
 750                 armpmu->start(armpmu);
 751                 break;
 752         default:
 753                 return NOTIFY_DONE;
 754         }
 755
 756         return NOTIFY_OK;
 757 }
 758
 759 static int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu)
 760 {
 761         cpu_pmu->cpu_pm_nb.notifier_call = cpu_pm_pmu_notify;
 762         return cpu_pm_register_notifier(&cpu_pmu->cpu_pm_nb);
 763 }
 764
 765 static void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu)
 766 {
 767         cpu_pm_unregister_notifier(&cpu_pmu->cpu_pm_nb);
 768 }
 769 #else
 770 static inline int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu) { return 0; }
 771 static inline void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu) { }
 772 #endif
 773
 774 static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 775 {
 776         int err;
 777
 778         err = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_STARTING,
 779                                        &cpu_pmu->node);
 780         if (err)
 781                 goto out;
 782
 783         err = cpu_pm_pmu_register(cpu_pmu);
 784         if (err)
 785                 goto out_unregister;
 786
 787         return 0;
 788
 789 out_unregister:
 790         cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
 791                                             &cpu_pmu->node);
 792 out:
 793         return err;
 794 }
 795
 796 static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
 797 {
 798         cpu_pm_pmu_unregister(cpu_pmu);
 799         cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
 800                                             &cpu_pmu->node);
 801 }
 802
 803 struct arm_pmu *armpmu_alloc(void)
 804 {
 805         struct arm_pmu *pmu;
 806         int cpu;
 807
 808         pmu = kzalloc(sizeof(*pmu), GFP_KERNEL);
 809         if (!pmu) {
 810                 pr_info("failed to allocate PMU device!\n");
 811                 goto out;
 812         }
 813
 814         pmu->hw_events = alloc_percpu(struct pmu_hw_events);
 815         if (!pmu->hw_events) {
 816                 pr_info("failed to allocate per-cpu PMU data.\n");
 817                 goto out_free_pmu;
 818         }
 819
 820         pmu->pmu = (struct pmu) {
 821                 .pmu_enable     = armpmu_enable,
 822                 .pmu_disable    = armpmu_disable,
 823                 .event_init     = armpmu_event_init,
 824                 .add            = armpmu_add,
 825                 .del            = armpmu_del,
 826                 .start          = armpmu_start,
 827                 .stop           = armpmu_stop,
 828                 .read           = armpmu_read,
 829                 .filter_match   = armpmu_filter_match,
 830                 .attr_groups    = pmu->attr_groups,
 831                 /*
 832                  * This is a CPU PMU potentially in a heterogeneous
 833                  * configuration (e.g. big.LITTLE). This is not an uncore PMU,
 834                  * and we have taken ctx sharing into account (e.g. with our
 835                  * pmu::filter_match callback and pmu::event_init group
 836                  * validation).
 837                  */
 838                 .capabilities   = PERF_PMU_CAP_HETEROGENEOUS_CPUS,
 839         };
 840
 841         pmu->attr_groups[ARMPMU_ATTR_GROUP_COMMON] =
 842                 &armpmu_common_attr_group;
 843
 844         for_each_possible_cpu(cpu) {
 845                 struct pmu_hw_events *events;
 846
 847                 events = per_cpu_ptr(pmu->hw_events, cpu);
 848                 raw_spin_lock_init(&events->pmu_lock);
 849                 events->percpu_pmu = pmu;
 850         }
 851
 852         return pmu;
 853
 854 out_free_pmu:
 855         kfree(pmu);
 856 out:
 857         return NULL;
 858 }
 859
 860 void armpmu_free(struct arm_pmu *pmu)
 861 {
 862         free_percpu(pmu->hw_events);
 863         kfree(pmu);
 864 }
 865
 866 int armpmu_register(struct arm_pmu *pmu)
 867 {
 868         int ret;
 869
 870         ret = cpu_pmu_init(pmu);
 871         if (ret)
 872                 return ret;
 873
 874         ret = perf_pmu_register(&pmu->pmu, pmu->name, -1);
 875         if (ret)
 876                 goto out_destroy;
 877
 878         if (!__oprofile_cpu_pmu)
 879                 __oprofile_cpu_pmu = pmu;
 880
 881         pr_info("enabled with %s PMU driver, %d counters available\n",
 882                 pmu->name, pmu->num_events);
 883
 884         return 0;
 885
 886 out_destroy:
 887         cpu_pmu_destroy(pmu);
 888         return ret;
 889 }
 890
 891 static int arm_pmu_hp_init(void)
 892 {
 893         int ret;
 894
 895         ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_STARTING,
 896                                       "perf/arm/pmu:starting",
 897                                       arm_perf_starting_cpu,
 898                                       arm_perf_teardown_cpu);
 899         if (ret)
 900                 pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n",
 901                        ret);
 902         return ret;
 903 }
 904 subsys_initcall(arm_pmu_hp_init);