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