drivers/perf/arm_pmu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #undef DEBUG
   3
   4 /*
   5  * ARM performance counter support.
   6  *
   7  * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
   8  * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
   9  *
  10  * This code is based on the sparc64 perf event code, which is in turn based
  11  * on the x86 code.
  12  */
  13 #define pr_fmt(fmt) "hw perfevents: " fmt
  14
  15 #include <linux/bitmap.h>
  16 #include <linux/cpumask.h>
  17 #include <linux/cpu_pm.h>
  18 #include <linux/export.h>
  19 #include <linux/kernel.h>
  20 #include <linux/perf/arm_pmu.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 armpmu_count_irq_users(const int irq);
  30
  31 struct pmu_irq_ops {
  32         void (*enable_pmuirq)(unsigned int irq);
  33         void (*disable_pmuirq)(unsigned int irq);
  34         void (*free_pmuirq)(unsigned int irq, int cpu, void __percpu *devid);
  35 };
  36
  37 static void armpmu_free_pmuirq(unsigned int irq, int cpu, void __percpu *devid)
  38 {
  39         free_irq(irq, per_cpu_ptr(devid, cpu));
  40 }
  41
  42 static const struct pmu_irq_ops pmuirq_ops = {
  43         .enable_pmuirq = enable_irq,
  44         .disable_pmuirq = disable_irq_nosync,
  45         .free_pmuirq = armpmu_free_pmuirq
  46 };
  47
  48 static void armpmu_free_pmunmi(unsigned int irq, int cpu, void __percpu *devid)
  49 {
  50         free_nmi(irq, per_cpu_ptr(devid, cpu));
  51 }
  52
  53 static const struct pmu_irq_ops pmunmi_ops = {
  54         .enable_pmuirq = enable_nmi,
  55         .disable_pmuirq = disable_nmi_nosync,
  56         .free_pmuirq = armpmu_free_pmunmi
  57 };
  58
  59 static void armpmu_enable_percpu_pmuirq(unsigned int irq)
  60 {
  61         enable_percpu_irq(irq, IRQ_TYPE_NONE);
  62 }
  63
  64 static void armpmu_free_percpu_pmuirq(unsigned int irq, int cpu,
  65                                    void __percpu *devid)
  66 {
  67         if (armpmu_count_irq_users(irq) == 1)
  68                 free_percpu_irq(irq, devid);
  69 }
  70
  71 static const struct pmu_irq_ops percpu_pmuirq_ops = {
  72         .enable_pmuirq = armpmu_enable_percpu_pmuirq,
  73         .disable_pmuirq = disable_percpu_irq,
  74         .free_pmuirq = armpmu_free_percpu_pmuirq
  75 };
  76
  77 static void armpmu_enable_percpu_pmunmi(unsigned int irq)
  78 {
  79         if (!prepare_percpu_nmi(irq))
  80                 enable_percpu_nmi(irq, IRQ_TYPE_NONE);
  81 }
  82
  83 static void armpmu_disable_percpu_pmunmi(unsigned int irq)
  84 {
  85         disable_percpu_nmi(irq);
  86         teardown_percpu_nmi(irq);
  87 }
  88
  89 static void armpmu_free_percpu_pmunmi(unsigned int irq, int cpu,
  90                                       void __percpu *devid)
  91 {
  92         if (armpmu_count_irq_users(irq) == 1)
  93                 free_percpu_nmi(irq, devid);
  94 }
  95
  96 static const struct pmu_irq_ops percpu_pmunmi_ops = {
  97         .enable_pmuirq = armpmu_enable_percpu_pmunmi,
  98         .disable_pmuirq = armpmu_disable_percpu_pmunmi,
  99         .free_pmuirq = armpmu_free_percpu_pmunmi
 100 };
 101
 102 static DEFINE_PER_CPU(struct arm_pmu *, cpu_armpmu);
 103 static DEFINE_PER_CPU(int, cpu_irq);
 104 static DEFINE_PER_CPU(const struct pmu_irq_ops *, cpu_irq_ops);
 105
 106 static bool has_nmi;
 107
 108 static inline u64 arm_pmu_event_max_period(struct perf_event *event)
 109 {
 110         if (event->hw.flags & ARMPMU_EVT_64BIT)
 111                 return GENMASK_ULL(63, 0);
 112         else if (event->hw.flags & ARMPMU_EVT_63BIT)
 113                 return GENMASK_ULL(62, 0);
 114         else if (event->hw.flags & ARMPMU_EVT_47BIT)
 115                 return GENMASK_ULL(46, 0);
 116         else
 117                 return GENMASK_ULL(31, 0);
 118 }
 119
 120 static int
 121 armpmu_map_cache_event(const unsigned (*cache_map)
 122                                       [PERF_COUNT_HW_CACHE_MAX]
 123                                       [PERF_COUNT_HW_CACHE_OP_MAX]
 124                                       [PERF_COUNT_HW_CACHE_RESULT_MAX],
 125                        u64 config)
 126 {
 127         unsigned int cache_type, cache_op, cache_result, ret;
 128
 129         cache_type = (config >>  0) & 0xff;
 130         if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
 131                 return -EINVAL;
 132
 133         cache_op = (config >>  8) & 0xff;
 134         if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
 135                 return -EINVAL;
 136
 137         cache_result = (config >> 16) & 0xff;
 138         if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
 139                 return -EINVAL;
 140
 141         if (!cache_map)
 142                 return -ENOENT;
 143
 144         ret = (int)(*cache_map)[cache_type][cache_op][cache_result];
 145
 146         if (ret == CACHE_OP_UNSUPPORTED)
 147                 return -ENOENT;
 148
 149         return ret;
 150 }
 151
 152 static int
 153 armpmu_map_hw_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
 154 {
 155         int mapping;
 156
 157         if (config >= PERF_COUNT_HW_MAX)
 158                 return -EINVAL;
 159
 160         if (!event_map)
 161                 return -ENOENT;
 162
 163         mapping = (*event_map)[config];
 164         return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping;
 165 }
 166
 167 static int
 168 armpmu_map_raw_event(u32 raw_event_mask, u64 config)
 169 {
 170         return (int)(config & raw_event_mask);
 171 }
 172
 173 int
 174 armpmu_map_event(struct perf_event *event,
 175                  const unsigned (*event_map)[PERF_COUNT_HW_MAX],
 176                  const unsigned (*cache_map)
 177                                 [PERF_COUNT_HW_CACHE_MAX]
 178                                 [PERF_COUNT_HW_CACHE_OP_MAX]
 179                                 [PERF_COUNT_HW_CACHE_RESULT_MAX],
 180                  u32 raw_event_mask)
 181 {
 182         u64 config = event->attr.config;
 183         int type = event->attr.type;
 184
 185         if (type == event->pmu->type)
 186                 return armpmu_map_raw_event(raw_event_mask, config);
 187
 188         switch (type) {
 189         case PERF_TYPE_HARDWARE:
 190                 return armpmu_map_hw_event(event_map, config);
 191         case PERF_TYPE_HW_CACHE:
 192                 return armpmu_map_cache_event(cache_map, config);
 193         case PERF_TYPE_RAW:
 194                 return armpmu_map_raw_event(raw_event_mask, config);
 195         }
 196
 197         return -ENOENT;
 198 }
 199
 200 int armpmu_event_set_period(struct perf_event *event)
 201 {
 202         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 203         struct hw_perf_event *hwc = &event->hw;
 204         s64 left = local64_read(&hwc->period_left);
 205         s64 period = hwc->sample_period;
 206         u64 max_period;
 207         int ret = 0;
 208
 209         max_period = arm_pmu_event_max_period(event);
 210         if (unlikely(left <= -period)) {
 211                 left = period;
 212                 local64_set(&hwc->period_left, left);
 213                 hwc->last_period = period;
 214                 ret = 1;
 215         }
 216
 217         if (unlikely(left <= 0)) {
 218                 left += period;
 219                 local64_set(&hwc->period_left, left);
 220                 hwc->last_period = period;
 221                 ret = 1;
 222         }
 223
 224         /*
 225          * Limit the maximum period to prevent the counter value
 226          * from overtaking the one we are about to program. In
 227          * effect we are reducing max_period to account for
 228          * interrupt latency (and we are being very conservative).
 229          */
 230         if (left > (max_period >> 1))
 231                 left = (max_period >> 1);
 232
 233         local64_set(&hwc->prev_count, (u64)-left);
 234
 235         armpmu->write_counter(event, (u64)(-left) & max_period);
 236
 237         perf_event_update_userpage(event);
 238
 239         return ret;
 240 }
 241
 242 u64 armpmu_event_update(struct perf_event *event)
 243 {
 244         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 245         struct hw_perf_event *hwc = &event->hw;
 246         u64 delta, prev_raw_count, new_raw_count;
 247         u64 max_period = arm_pmu_event_max_period(event);
 248
 249 again:
 250         prev_raw_count = local64_read(&hwc->prev_count);
 251         new_raw_count = armpmu->read_counter(event);
 252
 253         if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
 254                              new_raw_count) != prev_raw_count)
 255                 goto again;
 256
 257         delta = (new_raw_count - prev_raw_count) & max_period;
 258
 259         local64_add(delta, &event->count);
 260         local64_sub(delta, &hwc->period_left);
 261
 262         return new_raw_count;
 263 }
 264
 265 static void
 266 armpmu_read(struct perf_event *event)
 267 {
 268         armpmu_event_update(event);
 269 }
 270
 271 static void
 272 armpmu_stop(struct perf_event *event, int flags)
 273 {
 274         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 275         struct hw_perf_event *hwc = &event->hw;
 276
 277         /*
 278          * ARM pmu always has to update the counter, so ignore
 279          * PERF_EF_UPDATE, see comments in armpmu_start().
 280          */
 281         if (!(hwc->state & PERF_HES_STOPPED)) {
 282                 armpmu->disable(event);
 283                 armpmu_event_update(event);
 284                 hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
 285         }
 286 }
 287
 288 static void armpmu_start(struct perf_event *event, int flags)
 289 {
 290         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 291         struct hw_perf_event *hwc = &event->hw;
 292
 293         /*
 294          * ARM pmu always has to reprogram the period, so ignore
 295          * PERF_EF_RELOAD, see the comment below.
 296          */
 297         if (flags & PERF_EF_RELOAD)
 298                 WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
 299
 300         hwc->state = 0;
 301         /*
 302          * Set the period again. Some counters can't be stopped, so when we
 303          * were stopped we simply disabled the IRQ source and the counter
 304          * may have been left counting. If we don't do this step then we may
 305          * get an interrupt too soon or *way* too late if the overflow has
 306          * happened since disabling.
 307          */
 308         armpmu_event_set_period(event);
 309         armpmu->enable(event);
 310 }
 311
 312 static void
 313 armpmu_del(struct perf_event *event, int flags)
 314 {
 315         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 316         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 317         struct hw_perf_event *hwc = &event->hw;
 318         int idx = hwc->idx;
 319
 320         armpmu_stop(event, PERF_EF_UPDATE);
 321         hw_events->events[idx] = NULL;
 322         armpmu->clear_event_idx(hw_events, event);
 323         perf_event_update_userpage(event);
 324         /* Clear the allocated counter */
 325         hwc->idx = -1;
 326 }
 327
 328 static int
 329 armpmu_add(struct perf_event *event, int flags)
 330 {
 331         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 332         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 333         struct hw_perf_event *hwc = &event->hw;
 334         int idx;
 335
 336         /* An event following a process won't be stopped earlier */
 337         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 338                 return -ENOENT;
 339
 340         /* If we don't have a space for the counter then finish early. */
 341         idx = armpmu->get_event_idx(hw_events, event);
 342         if (idx < 0)
 343                 return idx;
 344
 345         /*
 346          * If there is an event in the counter we are going to use then make
 347          * sure it is disabled.
 348          */
 349         event->hw.idx = idx;
 350         armpmu->disable(event);
 351         hw_events->events[idx] = event;
 352
 353         hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
 354         if (flags & PERF_EF_START)
 355                 armpmu_start(event, PERF_EF_RELOAD);
 356
 357         /* Propagate our changes to the userspace mapping. */
 358         perf_event_update_userpage(event);
 359
 360         return 0;
 361 }
 362
 363 static int
 364 validate_event(struct pmu *pmu, struct pmu_hw_events *hw_events,
 365                                struct perf_event *event)
 366 {
 367         struct arm_pmu *armpmu;
 368
 369         if (is_software_event(event))
 370                 return 1;
 371
 372         /*
 373          * Reject groups spanning multiple HW PMUs (e.g. CPU + CCI). The
 374          * core perf code won't check that the pmu->ctx == leader->ctx
 375          * until after pmu->event_init(event).
 376          */
 377         if (event->pmu != pmu)
 378                 return 0;
 379
 380         if (event->state < PERF_EVENT_STATE_OFF)
 381                 return 1;
 382
 383         if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec)
 384                 return 1;
 385
 386         armpmu = to_arm_pmu(event->pmu);
 387         return armpmu->get_event_idx(hw_events, event) >= 0;
 388 }
 389
 390 static int
 391 validate_group(struct perf_event *event)
 392 {
 393         struct perf_event *sibling, *leader = event->group_leader;
 394         struct pmu_hw_events fake_pmu;
 395
 396         /*
 397          * Initialise the fake PMU. We only need to populate the
 398          * used_mask for the purposes of validation.
 399          */
 400         memset(&fake_pmu.used_mask, 0, sizeof(fake_pmu.used_mask));
 401
 402         if (!validate_event(event->pmu, &fake_pmu, leader))
 403                 return -EINVAL;
 404
 405         if (event == leader)
 406                 return 0;
 407
 408         for_each_sibling_event(sibling, leader) {
 409                 if (!validate_event(event->pmu, &fake_pmu, sibling))
 410                         return -EINVAL;
 411         }
 412
 413         if (!validate_event(event->pmu, &fake_pmu, event))
 414                 return -EINVAL;
 415
 416         return 0;
 417 }
 418
 419 static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
 420 {
 421         struct arm_pmu *armpmu;
 422         int ret;
 423         u64 start_clock, finish_clock;
 424
 425         /*
 426          * we request the IRQ with a (possibly percpu) struct arm_pmu**, but
 427          * the handlers expect a struct arm_pmu*. The percpu_irq framework will
 428          * do any necessary shifting, we just need to perform the first
 429          * dereference.
 430          */
 431         armpmu = *(void **)dev;
 432         if (WARN_ON_ONCE(!armpmu))
 433                 return IRQ_NONE;
 434
 435         start_clock = sched_clock();
 436         ret = armpmu->handle_irq(armpmu);
 437         finish_clock = sched_clock();
 438
 439         perf_sample_event_took(finish_clock - start_clock);
 440         return ret;
 441 }
 442
 443 static int
 444 __hw_perf_event_init(struct perf_event *event)
 445 {
 446         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 447         struct hw_perf_event *hwc = &event->hw;
 448         int mapping, ret;
 449
 450         hwc->flags = 0;
 451         mapping = armpmu->map_event(event);
 452
 453         if (mapping < 0) {
 454                 pr_debug("event %x:%llx not supported\n", event->attr.type,
 455                          event->attr.config);
 456                 return mapping;
 457         }
 458
 459         /*
 460          * We don't assign an index until we actually place the event onto
 461          * hardware. Use -1 to signify that we haven't decided where to put it
 462          * yet. For SMP systems, each core has it's own PMU so we can't do any
 463          * clever allocation or constraints checking at this point.
 464          */
 465         hwc->idx                = -1;
 466         hwc->config_base        = 0;
 467         hwc->config             = 0;
 468         hwc->event_base         = 0;
 469
 470         /*
 471          * Check whether we need to exclude the counter from certain modes.
 472          */
 473         if (armpmu->set_event_filter) {
 474                 ret = armpmu->set_event_filter(hwc, &event->attr);
 475                 if (ret)
 476                         return ret;
 477         }
 478
 479         /*
 480          * Store the event encoding into the config_base field.
 481          */
 482         hwc->config_base            |= (unsigned long)mapping;
 483
 484         if (!is_sampling_event(event)) {
 485                 /*
 486                  * For non-sampling runs, limit the sample_period to half
 487                  * of the counter width. That way, the new counter value
 488                  * is far less likely to overtake the previous one unless
 489                  * you have some serious IRQ latency issues.
 490                  */
 491                 hwc->sample_period  = arm_pmu_event_max_period(event) >> 1;
 492                 hwc->last_period    = hwc->sample_period;
 493                 local64_set(&hwc->period_left, hwc->sample_period);
 494         }
 495
 496         return validate_group(event);
 497 }
 498
 499 static int armpmu_event_init(struct perf_event *event)
 500 {
 501         struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 502
 503         /*
 504          * Reject CPU-affine events for CPUs that are of a different class to
 505          * that which this PMU handles. Process-following events (where
 506          * event->cpu == -1) can be migrated between CPUs, and thus we have to
 507          * reject them later (in armpmu_add) if they're scheduled on a
 508          * different class of CPU.
 509          */
 510         if (event->cpu != -1 &&
 511                 !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus))
 512                 return -ENOENT;
 513
 514         /* does not support taken branch sampling */
 515         if (has_branch_stack(event))
 516                 return -EOPNOTSUPP;
 517
 518         return __hw_perf_event_init(event);
 519 }
 520
 521 static void armpmu_enable(struct pmu *pmu)
 522 {
 523         struct arm_pmu *armpmu = to_arm_pmu(pmu);
 524         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 525         bool enabled = !bitmap_empty(hw_events->used_mask, armpmu->num_events);
 526
 527         /* For task-bound events we may be called on other CPUs */
 528         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 529                 return;
 530
 531         if (enabled)
 532                 armpmu->start(armpmu);
 533 }
 534
 535 static void armpmu_disable(struct pmu *pmu)
 536 {
 537         struct arm_pmu *armpmu = to_arm_pmu(pmu);
 538
 539         /* For task-bound events we may be called on other CPUs */
 540         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 541                 return;
 542
 543         armpmu->stop(armpmu);
 544 }
 545
 546 /*
 547  * In heterogeneous systems, events are specific to a particular
 548  * microarchitecture, and aren't suitable for another. Thus, only match CPUs of
 549  * the same microarchitecture.
 550  */
 551 static bool armpmu_filter(struct pmu *pmu, int cpu)
 552 {
 553         struct arm_pmu *armpmu = to_arm_pmu(pmu);
 554         return !cpumask_test_cpu(cpu, &armpmu->supported_cpus);
 555 }
 556
 557 static ssize_t cpus_show(struct device *dev,
 558                          struct device_attribute *attr, char *buf)
 559 {
 560         struct arm_pmu *armpmu = to_arm_pmu(dev_get_drvdata(dev));
 561         return cpumap_print_to_pagebuf(true, buf, &armpmu->supported_cpus);
 562 }
 563
 564 static DEVICE_ATTR_RO(cpus);
 565
 566 static struct attribute *armpmu_common_attrs[] = {
 567         &dev_attr_cpus.attr,
 568         NULL,
 569 };
 570
 571 static const struct attribute_group armpmu_common_attr_group = {
 572         .attrs = armpmu_common_attrs,
 573 };
 574
 575 static int armpmu_count_irq_users(const int irq)
 576 {
 577         int cpu, count = 0;
 578
 579         for_each_possible_cpu(cpu) {
 580                 if (per_cpu(cpu_irq, cpu) == irq)
 581                         count++;
 582         }
 583
 584         return count;
 585 }
 586
 587 static const struct pmu_irq_ops *armpmu_find_irq_ops(int irq)
 588 {
 589         const struct pmu_irq_ops *ops = NULL;
 590         int cpu;
 591
 592         for_each_possible_cpu(cpu) {
 593                 if (per_cpu(cpu_irq, cpu) != irq)
 594                         continue;
 595
 596                 ops = per_cpu(cpu_irq_ops, cpu);
 597                 if (ops)
 598                         break;
 599         }
 600
 601         return ops;
 602 }
 603
 604 void armpmu_free_irq(int irq, int cpu)
 605 {
 606         if (per_cpu(cpu_irq, cpu) == 0)
 607                 return;
 608         if (WARN_ON(irq != per_cpu(cpu_irq, cpu)))
 609                 return;
 610
 611         per_cpu(cpu_irq_ops, cpu)->free_pmuirq(irq, cpu, &cpu_armpmu);
 612
 613         per_cpu(cpu_irq, cpu) = 0;
 614         per_cpu(cpu_irq_ops, cpu) = NULL;
 615 }
 616
 617 int armpmu_request_irq(int irq, int cpu)
 618 {
 619         int err = 0;
 620         const irq_handler_t handler = armpmu_dispatch_irq;
 621         const struct pmu_irq_ops *irq_ops;
 622
 623         if (!irq)
 624                 return 0;
 625
 626         if (!irq_is_percpu_devid(irq)) {
 627                 unsigned long irq_flags;
 628
 629                 err = irq_force_affinity(irq, cpumask_of(cpu));
 630
 631                 if (err && num_possible_cpus() > 1) {
 632                         pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
 633                                 irq, cpu);
 634                         goto err_out;
 635                 }
 636
 637                 irq_flags = IRQF_PERCPU |
 638                             IRQF_NOBALANCING | IRQF_NO_AUTOEN |
 639                             IRQF_NO_THREAD;
 640
 641                 err = request_nmi(irq, handler, irq_flags, "arm-pmu",
 642                                   per_cpu_ptr(&cpu_armpmu, cpu));
 643
 644                 /* If cannot get an NMI, get a normal interrupt */
 645                 if (err) {
 646                         err = request_irq(irq, handler, irq_flags, "arm-pmu",
 647                                           per_cpu_ptr(&cpu_armpmu, cpu));
 648                         irq_ops = &pmuirq_ops;
 649                 } else {
 650                         has_nmi = true;
 651                         irq_ops = &pmunmi_ops;
 652                 }
 653         } else if (armpmu_count_irq_users(irq) == 0) {
 654                 err = request_percpu_nmi(irq, handler, "arm-pmu", &cpu_armpmu);
 655
 656                 /* If cannot get an NMI, get a normal interrupt */
 657                 if (err) {
 658                         err = request_percpu_irq(irq, handler, "arm-pmu",
 659                                                  &cpu_armpmu);
 660                         irq_ops = &percpu_pmuirq_ops;
 661                 } else {
 662                         has_nmi = true;
 663                         irq_ops = &percpu_pmunmi_ops;
 664                 }
 665         } else {
 666                 /* Per cpudevid irq was already requested by another CPU */
 667                 irq_ops = armpmu_find_irq_ops(irq);
 668
 669                 if (WARN_ON(!irq_ops))
 670                         err = -EINVAL;
 671         }
 672
 673         if (err)
 674                 goto err_out;
 675
 676         per_cpu(cpu_irq, cpu) = irq;
 677         per_cpu(cpu_irq_ops, cpu) = irq_ops;
 678         return 0;
 679
 680 err_out:
 681         pr_err("unable to request IRQ%d for ARM PMU counters\n", irq);
 682         return err;
 683 }
 684
 685 static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu)
 686 {
 687         struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
 688         return per_cpu(hw_events->irq, cpu);
 689 }
 690
 691 bool arm_pmu_irq_is_nmi(void)
 692 {
 693         return has_nmi;
 694 }
 695
 696 /*
 697  * PMU hardware loses all context when a CPU goes offline.
 698  * When a CPU is hotplugged back in, since some hardware registers are
 699  * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
 700  * junk values out of them.
 701  */
 702 static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
 703 {
 704         struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
 705         int irq;
 706
 707         if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
 708                 return 0;
 709         if (pmu->reset)
 710                 pmu->reset(pmu);
 711
 712         per_cpu(cpu_armpmu, cpu) = pmu;
 713
 714         irq = armpmu_get_cpu_irq(pmu, cpu);
 715         if (irq)
 716                 per_cpu(cpu_irq_ops, cpu)->enable_pmuirq(irq);
 717
 718         return 0;
 719 }
 720
 721 static int arm_perf_teardown_cpu(unsigned int cpu, struct hlist_node *node)
 722 {
 723         struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
 724         int irq;
 725
 726         if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
 727                 return 0;
 728
 729         irq = armpmu_get_cpu_irq(pmu, cpu);
 730         if (irq)
 731                 per_cpu(cpu_irq_ops, cpu)->disable_pmuirq(irq);
 732
 733         per_cpu(cpu_armpmu, cpu) = NULL;
 734
 735         return 0;
 736 }
 737
 738 #ifdef CONFIG_CPU_PM
 739 static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd)
 740 {
 741         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 742         struct perf_event *event;
 743         int idx;
 744
 745         for (idx = 0; idx < armpmu->num_events; idx++) {
 746                 event = hw_events->events[idx];
 747                 if (!event)
 748                         continue;
 749
 750                 switch (cmd) {
 751                 case CPU_PM_ENTER:
 752                         /*
 753                          * Stop and update the counter
 754                          */
 755                         armpmu_stop(event, PERF_EF_UPDATE);
 756                         break;
 757                 case CPU_PM_EXIT:
 758                 case CPU_PM_ENTER_FAILED:
 759                          /*
 760                           * Restore and enable the counter.
 761                           */
 762                         armpmu_start(event, PERF_EF_RELOAD);
 763                         break;
 764                 default:
 765                         break;
 766                 }
 767         }
 768 }
 769
 770 static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
 771                              void *v)
 772 {
 773         struct arm_pmu *armpmu = container_of(b, struct arm_pmu, cpu_pm_nb);
 774         struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
 775         bool enabled = !bitmap_empty(hw_events->used_mask, armpmu->num_events);
 776
 777         if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
 778                 return NOTIFY_DONE;
 779
 780         /*
 781          * Always reset the PMU registers on power-up even if
 782          * there are no events running.
 783          */
 784         if (cmd == CPU_PM_EXIT && armpmu->reset)
 785                 armpmu->reset(armpmu);
 786
 787         if (!enabled)
 788                 return NOTIFY_OK;
 789
 790         switch (cmd) {
 791         case CPU_PM_ENTER:
 792                 armpmu->stop(armpmu);
 793                 cpu_pm_pmu_setup(armpmu, cmd);
 794                 break;
 795         case CPU_PM_EXIT:
 796         case CPU_PM_ENTER_FAILED:
 797                 cpu_pm_pmu_setup(armpmu, cmd);
 798                 armpmu->start(armpmu);
 799                 break;
 800         default:
 801                 return NOTIFY_DONE;
 802         }
 803
 804         return NOTIFY_OK;
 805 }
 806
 807 static int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu)
 808 {
 809         cpu_pmu->cpu_pm_nb.notifier_call = cpu_pm_pmu_notify;
 810         return cpu_pm_register_notifier(&cpu_pmu->cpu_pm_nb);
 811 }
 812
 813 static void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu)
 814 {
 815         cpu_pm_unregister_notifier(&cpu_pmu->cpu_pm_nb);
 816 }
 817 #else
 818 static inline int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu) { return 0; }
 819 static inline void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu) { }
 820 #endif
 821
 822 static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 823 {
 824         int err;
 825
 826         err = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_STARTING,
 827                                        &cpu_pmu->node);
 828         if (err)
 829                 goto out;
 830
 831         err = cpu_pm_pmu_register(cpu_pmu);
 832         if (err)
 833                 goto out_unregister;
 834
 835         return 0;
 836
 837 out_unregister:
 838         cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
 839                                             &cpu_pmu->node);
 840 out:
 841         return err;
 842 }
 843
 844 static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
 845 {
 846         cpu_pm_pmu_unregister(cpu_pmu);
 847         cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
 848                                             &cpu_pmu->node);
 849 }
 850
 851 struct arm_pmu *armpmu_alloc(void)
 852 {
 853         struct arm_pmu *pmu;
 854         int cpu;
 855
 856         pmu = kzalloc(sizeof(*pmu), GFP_KERNEL);
 857         if (!pmu)
 858                 goto out;
 859
 860         pmu->hw_events = alloc_percpu_gfp(struct pmu_hw_events, GFP_KERNEL);
 861         if (!pmu->hw_events) {
 862                 pr_info("failed to allocate per-cpu PMU data.\n");
 863                 goto out_free_pmu;
 864         }
 865
 866         pmu->pmu = (struct pmu) {
 867                 .pmu_enable     = armpmu_enable,
 868                 .pmu_disable    = armpmu_disable,
 869                 .event_init     = armpmu_event_init,
 870                 .add            = armpmu_add,
 871                 .del            = armpmu_del,
 872                 .start          = armpmu_start,
 873                 .stop           = armpmu_stop,
 874                 .read           = armpmu_read,
 875                 .filter         = armpmu_filter,
 876                 .attr_groups    = pmu->attr_groups,
 877                 /*
 878                  * This is a CPU PMU potentially in a heterogeneous
 879                  * configuration (e.g. big.LITTLE) so
 880                  * PERF_PMU_CAP_EXTENDED_HW_TYPE is required to open
 881                  * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE events on a
 882                  * specific PMU.
 883                  */
 884                 .capabilities   = PERF_PMU_CAP_EXTENDED_REGS |
 885                                   PERF_PMU_CAP_EXTENDED_HW_TYPE,
 886         };
 887
 888         pmu->attr_groups[ARMPMU_ATTR_GROUP_COMMON] =
 889                 &armpmu_common_attr_group;
 890
 891         for_each_possible_cpu(cpu) {
 892                 struct pmu_hw_events *events;
 893
 894                 events = per_cpu_ptr(pmu->hw_events, cpu);
 895                 events->percpu_pmu = pmu;
 896         }
 897
 898         return pmu;
 899
 900 out_free_pmu:
 901         kfree(pmu);
 902 out:
 903         return NULL;
 904 }
 905
 906 void armpmu_free(struct arm_pmu *pmu)
 907 {
 908         free_percpu(pmu->hw_events);
 909         kfree(pmu);
 910 }
 911
 912 int armpmu_register(struct arm_pmu *pmu)
 913 {
 914         int ret;
 915
 916         ret = cpu_pmu_init(pmu);
 917         if (ret)
 918                 return ret;
 919
 920         if (!pmu->set_event_filter)
 921                 pmu->pmu.capabilities |= PERF_PMU_CAP_NO_EXCLUDE;
 922
 923         ret = perf_pmu_register(&pmu->pmu, pmu->name, -1);
 924         if (ret)
 925                 goto out_destroy;
 926
 927         pr_info("enabled with %s PMU driver, %d counters available%s\n",
 928                 pmu->name, pmu->num_events,
 929                 has_nmi ? ", using NMIs" : "");
 930
 931         kvm_host_pmu_init(pmu);
 932
 933         return 0;
 934
 935 out_destroy:
 936         cpu_pmu_destroy(pmu);
 937         return ret;
 938 }
 939
 940 static int arm_pmu_hp_init(void)
 941 {
 942         int ret;
 943
 944         ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_STARTING,
 945                                       "perf/arm/pmu:starting",
 946                                       arm_perf_starting_cpu,
 947                                       arm_perf_teardown_cpu);
 948         if (ret)
 949                 pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n",
 950                        ret);
 951         return ret;
 952 }
 953 subsys_initcall(arm_pmu_hp_init);