arch/powerpc/perf/core-fsl-emb.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Performance event support - Freescale Embedded Performance Monitor
   4  *
   5  * Copyright 2008-2009 Paul Mackerras, IBM Corporation.
   6  * Copyright 2010 Freescale Semiconductor, Inc.
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/sched.h>
  10 #include <linux/perf_event.h>
  11 #include <linux/percpu.h>
  12 #include <linux/hardirq.h>
  13 #include <asm/reg_fsl_emb.h>
  14 #include <asm/pmc.h>
  15 #include <asm/machdep.h>
  16 #include <asm/firmware.h>
  17 #include <asm/ptrace.h>
  18
  19 struct cpu_hw_events {
  20         int n_events;
  21         int disabled;
  22         u8  pmcs_enabled;
  23         struct perf_event *event[MAX_HWEVENTS];
  24 };
  25 static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
  26
  27 static struct fsl_emb_pmu *ppmu;
  28
  29 /* Number of perf_events counting hardware events */
  30 static atomic_t num_events;
  31 /* Used to avoid races in calling reserve/release_pmc_hardware */
  32 static DEFINE_MUTEX(pmc_reserve_mutex);
  33
  34 /*
  35  * If interrupts were soft-disabled when a PMU interrupt occurs, treat
  36  * it as an NMI.
  37  */
  38 static inline int perf_intr_is_nmi(struct pt_regs *regs)
  39 {
  40 #ifdef __powerpc64__
  41         return (regs->softe & IRQS_DISABLED);
  42 #else
  43         return 0;
  44 #endif
  45 }
  46
  47 static void perf_event_interrupt(struct pt_regs *regs);
  48
  49 /*
  50  * Read one performance monitor counter (PMC).
  51  */
  52 static unsigned long read_pmc(int idx)
  53 {
  54         unsigned long val;
  55
  56         switch (idx) {
  57         case 0:
  58                 val = mfpmr(PMRN_PMC0);
  59                 break;
  60         case 1:
  61                 val = mfpmr(PMRN_PMC1);
  62                 break;
  63         case 2:
  64                 val = mfpmr(PMRN_PMC2);
  65                 break;
  66         case 3:
  67                 val = mfpmr(PMRN_PMC3);
  68                 break;
  69         case 4:
  70                 val = mfpmr(PMRN_PMC4);
  71                 break;
  72         case 5:
  73                 val = mfpmr(PMRN_PMC5);
  74                 break;
  75         default:
  76                 printk(KERN_ERR "oops trying to read PMC%d\n", idx);
  77                 val = 0;
  78         }
  79         return val;
  80 }
  81
  82 /*
  83  * Write one PMC.
  84  */
  85 static void write_pmc(int idx, unsigned long val)
  86 {
  87         switch (idx) {
  88         case 0:
  89                 mtpmr(PMRN_PMC0, val);
  90                 break;
  91         case 1:
  92                 mtpmr(PMRN_PMC1, val);
  93                 break;
  94         case 2:
  95                 mtpmr(PMRN_PMC2, val);
  96                 break;
  97         case 3:
  98                 mtpmr(PMRN_PMC3, val);
  99                 break;
 100         case 4:
 101                 mtpmr(PMRN_PMC4, val);
 102                 break;
 103         case 5:
 104                 mtpmr(PMRN_PMC5, val);
 105                 break;
 106         default:
 107                 printk(KERN_ERR "oops trying to write PMC%d\n", idx);
 108         }
 109
 110         isync();
 111 }
 112
 113 /*
 114  * Write one local control A register
 115  */
 116 static void write_pmlca(int idx, unsigned long val)
 117 {
 118         switch (idx) {
 119         case 0:
 120                 mtpmr(PMRN_PMLCA0, val);
 121                 break;
 122         case 1:
 123                 mtpmr(PMRN_PMLCA1, val);
 124                 break;
 125         case 2:
 126                 mtpmr(PMRN_PMLCA2, val);
 127                 break;
 128         case 3:
 129                 mtpmr(PMRN_PMLCA3, val);
 130                 break;
 131         case 4:
 132                 mtpmr(PMRN_PMLCA4, val);
 133                 break;
 134         case 5:
 135                 mtpmr(PMRN_PMLCA5, val);
 136                 break;
 137         default:
 138                 printk(KERN_ERR "oops trying to write PMLCA%d\n", idx);
 139         }
 140
 141         isync();
 142 }
 143
 144 /*
 145  * Write one local control B register
 146  */
 147 static void write_pmlcb(int idx, unsigned long val)
 148 {
 149         switch (idx) {
 150         case 0:
 151                 mtpmr(PMRN_PMLCB0, val);
 152                 break;
 153         case 1:
 154                 mtpmr(PMRN_PMLCB1, val);
 155                 break;
 156         case 2:
 157                 mtpmr(PMRN_PMLCB2, val);
 158                 break;
 159         case 3:
 160                 mtpmr(PMRN_PMLCB3, val);
 161                 break;
 162         case 4:
 163                 mtpmr(PMRN_PMLCB4, val);
 164                 break;
 165         case 5:
 166                 mtpmr(PMRN_PMLCB5, val);
 167                 break;
 168         default:
 169                 printk(KERN_ERR "oops trying to write PMLCB%d\n", idx);
 170         }
 171
 172         isync();
 173 }
 174
 175 static void fsl_emb_pmu_read(struct perf_event *event)
 176 {
 177         s64 val, delta, prev;
 178
 179         if (event->hw.state & PERF_HES_STOPPED)
 180                 return;
 181
 182         /*
 183          * Performance monitor interrupts come even when interrupts
 184          * are soft-disabled, as long as interrupts are hard-enabled.
 185          * Therefore we treat them like NMIs.
 186          */
 187         do {
 188                 prev = local64_read(&event->hw.prev_count);
 189                 barrier();
 190                 val = read_pmc(event->hw.idx);
 191         } while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
 192
 193         /* The counters are only 32 bits wide */
 194         delta = (val - prev) & 0xfffffffful;
 195         local64_add(delta, &event->count);
 196         local64_sub(delta, &event->hw.period_left);
 197 }
 198
 199 /*
 200  * Disable all events to prevent PMU interrupts and to allow
 201  * events to be added or removed.
 202  */
 203 static void fsl_emb_pmu_disable(struct pmu *pmu)
 204 {
 205         struct cpu_hw_events *cpuhw;
 206         unsigned long flags;
 207
 208         local_irq_save(flags);
 209         cpuhw = this_cpu_ptr(&cpu_hw_events);
 210
 211         if (!cpuhw->disabled) {
 212                 cpuhw->disabled = 1;
 213
 214                 /*
 215                  * Check if we ever enabled the PMU on this cpu.
 216                  */
 217                 if (!cpuhw->pmcs_enabled) {
 218                         ppc_enable_pmcs();
 219                         cpuhw->pmcs_enabled = 1;
 220                 }
 221
 222                 if (atomic_read(&num_events)) {
 223                         /*
 224                          * Set the 'freeze all counters' bit, and disable
 225                          * interrupts.  The barrier is to make sure the
 226                          * mtpmr has been executed and the PMU has frozen
 227                          * the events before we return.
 228                          */
 229
 230                         mtpmr(PMRN_PMGC0, PMGC0_FAC);
 231                         isync();
 232                 }
 233         }
 234         local_irq_restore(flags);
 235 }
 236
 237 /*
 238  * Re-enable all events if disable == 0.
 239  * If we were previously disabled and events were added, then
 240  * put the new config on the PMU.
 241  */
 242 static void fsl_emb_pmu_enable(struct pmu *pmu)
 243 {
 244         struct cpu_hw_events *cpuhw;
 245         unsigned long flags;
 246
 247         local_irq_save(flags);
 248         cpuhw = this_cpu_ptr(&cpu_hw_events);
 249         if (!cpuhw->disabled)
 250                 goto out;
 251
 252         cpuhw->disabled = 0;
 253         ppc_set_pmu_inuse(cpuhw->n_events != 0);
 254
 255         if (cpuhw->n_events > 0) {
 256                 mtpmr(PMRN_PMGC0, PMGC0_PMIE | PMGC0_FCECE);
 257                 isync();
 258         }
 259
 260  out:
 261         local_irq_restore(flags);
 262 }
 263
 264 static int collect_events(struct perf_event *group, int max_count,
 265                           struct perf_event *ctrs[])
 266 {
 267         int n = 0;
 268         struct perf_event *event;
 269
 270         if (!is_software_event(group)) {
 271                 if (n >= max_count)
 272                         return -1;
 273                 ctrs[n] = group;
 274                 n++;
 275         }
 276         for_each_sibling_event(event, group) {
 277                 if (!is_software_event(event) &&
 278                     event->state != PERF_EVENT_STATE_OFF) {
 279                         if (n >= max_count)
 280                                 return -1;
 281                         ctrs[n] = event;
 282                         n++;
 283                 }
 284         }
 285         return n;
 286 }
 287
 288 /* context locked on entry */
 289 static int fsl_emb_pmu_add(struct perf_event *event, int flags)
 290 {
 291         struct cpu_hw_events *cpuhw;
 292         int ret = -EAGAIN;
 293         int num_counters = ppmu->n_counter;
 294         u64 val;
 295         int i;
 296
 297         perf_pmu_disable(event->pmu);
 298         cpuhw = &get_cpu_var(cpu_hw_events);
 299
 300         if (event->hw.config & FSL_EMB_EVENT_RESTRICTED)
 301                 num_counters = ppmu->n_restricted;
 302
 303         /*
 304          * Allocate counters from top-down, so that restricted-capable
 305          * counters are kept free as long as possible.
 306          */
 307         for (i = num_counters - 1; i >= 0; i--) {
 308                 if (cpuhw->event[i])
 309                         continue;
 310
 311                 break;
 312         }
 313
 314         if (i < 0)
 315                 goto out;
 316
 317         event->hw.idx = i;
 318         cpuhw->event[i] = event;
 319         ++cpuhw->n_events;
 320
 321         val = 0;
 322         if (event->hw.sample_period) {
 323                 s64 left = local64_read(&event->hw.period_left);
 324                 if (left < 0x80000000L)
 325                         val = 0x80000000L - left;
 326         }
 327         local64_set(&event->hw.prev_count, val);
 328
 329         if (unlikely(!(flags & PERF_EF_START))) {
 330                 event->hw.state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
 331                 val = 0;
 332         } else {
 333                 event->hw.state &= ~(PERF_HES_STOPPED | PERF_HES_UPTODATE);
 334         }
 335
 336         write_pmc(i, val);
 337         perf_event_update_userpage(event);
 338
 339         write_pmlcb(i, event->hw.config >> 32);
 340         write_pmlca(i, event->hw.config_base);
 341
 342         ret = 0;
 343  out:
 344         put_cpu_var(cpu_hw_events);
 345         perf_pmu_enable(event->pmu);
 346         return ret;
 347 }
 348
 349 /* context locked on entry */
 350 static void fsl_emb_pmu_del(struct perf_event *event, int flags)
 351 {
 352         struct cpu_hw_events *cpuhw;
 353         int i = event->hw.idx;
 354
 355         perf_pmu_disable(event->pmu);
 356         if (i < 0)
 357                 goto out;
 358
 359         fsl_emb_pmu_read(event);
 360
 361         cpuhw = &get_cpu_var(cpu_hw_events);
 362
 363         WARN_ON(event != cpuhw->event[event->hw.idx]);
 364
 365         write_pmlca(i, 0);
 366         write_pmlcb(i, 0);
 367         write_pmc(i, 0);
 368
 369         cpuhw->event[i] = NULL;
 370         event->hw.idx = -1;
 371
 372         /*
 373          * TODO: if at least one restricted event exists, and we
 374          * just freed up a non-restricted-capable counter, and
 375          * there is a restricted-capable counter occupied by
 376          * a non-restricted event, migrate that event to the
 377          * vacated counter.
 378          */
 379
 380         cpuhw->n_events--;
 381
 382  out:
 383         perf_pmu_enable(event->pmu);
 384         put_cpu_var(cpu_hw_events);
 385 }
 386
 387 static void fsl_emb_pmu_start(struct perf_event *event, int ef_flags)
 388 {
 389         unsigned long flags;
 390         unsigned long val;
 391         s64 left;
 392
 393         if (event->hw.idx < 0 || !event->hw.sample_period)
 394                 return;
 395
 396         if (!(event->hw.state & PERF_HES_STOPPED))
 397                 return;
 398
 399         if (ef_flags & PERF_EF_RELOAD)
 400                 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
 401
 402         local_irq_save(flags);
 403         perf_pmu_disable(event->pmu);
 404
 405         event->hw.state = 0;
 406         left = local64_read(&event->hw.period_left);
 407         val = 0;
 408         if (left < 0x80000000L)
 409                 val = 0x80000000L - left;
 410         write_pmc(event->hw.idx, val);
 411
 412         perf_event_update_userpage(event);
 413         perf_pmu_enable(event->pmu);
 414         local_irq_restore(flags);
 415 }
 416
 417 static void fsl_emb_pmu_stop(struct perf_event *event, int ef_flags)
 418 {
 419         unsigned long flags;
 420
 421         if (event->hw.idx < 0 || !event->hw.sample_period)
 422                 return;
 423
 424         if (event->hw.state & PERF_HES_STOPPED)
 425                 return;
 426
 427         local_irq_save(flags);
 428         perf_pmu_disable(event->pmu);
 429
 430         fsl_emb_pmu_read(event);
 431         event->hw.state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
 432         write_pmc(event->hw.idx, 0);
 433
 434         perf_event_update_userpage(event);
 435         perf_pmu_enable(event->pmu);
 436         local_irq_restore(flags);
 437 }
 438
 439 /*
 440  * Release the PMU if this is the last perf_event.
 441  */
 442 static void hw_perf_event_destroy(struct perf_event *event)
 443 {
 444         if (!atomic_add_unless(&num_events, -1, 1)) {
 445                 mutex_lock(&pmc_reserve_mutex);
 446                 if (atomic_dec_return(&num_events) == 0)
 447                         release_pmc_hardware();
 448                 mutex_unlock(&pmc_reserve_mutex);
 449         }
 450 }
 451
 452 /*
 453  * Translate a generic cache event_id config to a raw event_id code.
 454  */
 455 static int hw_perf_cache_event(u64 config, u64 *eventp)
 456 {
 457         unsigned long type, op, result;
 458         int ev;
 459
 460         if (!ppmu->cache_events)
 461                 return -EINVAL;
 462
 463         /* unpack config */
 464         type = config & 0xff;
 465         op = (config >> 8) & 0xff;
 466         result = (config >> 16) & 0xff;
 467
 468         if (type >= PERF_COUNT_HW_CACHE_MAX ||
 469             op >= PERF_COUNT_HW_CACHE_OP_MAX ||
 470             result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
 471                 return -EINVAL;
 472
 473         ev = (*ppmu->cache_events)[type][op][result];
 474         if (ev == 0)
 475                 return -EOPNOTSUPP;
 476         if (ev == -1)
 477                 return -EINVAL;
 478         *eventp = ev;
 479         return 0;
 480 }
 481
 482 static int fsl_emb_pmu_event_init(struct perf_event *event)
 483 {
 484         u64 ev;
 485         struct perf_event *events[MAX_HWEVENTS];
 486         int n;
 487         int err;
 488         int num_restricted;
 489         int i;
 490
 491         if (ppmu->n_counter > MAX_HWEVENTS) {
 492                 WARN(1, "No. of perf counters (%d) is higher than max array size(%d)\n",
 493                         ppmu->n_counter, MAX_HWEVENTS);
 494                 ppmu->n_counter = MAX_HWEVENTS;
 495         }
 496
 497         switch (event->attr.type) {
 498         case PERF_TYPE_HARDWARE:
 499                 ev = event->attr.config;
 500                 if (ev >= ppmu->n_generic || ppmu->generic_events[ev] == 0)
 501                         return -EOPNOTSUPP;
 502                 ev = ppmu->generic_events[ev];
 503                 break;
 504
 505         case PERF_TYPE_HW_CACHE:
 506                 err = hw_perf_cache_event(event->attr.config, &ev);
 507                 if (err)
 508                         return err;
 509                 break;
 510
 511         case PERF_TYPE_RAW:
 512                 ev = event->attr.config;
 513                 break;
 514
 515         default:
 516                 return -ENOENT;
 517         }
 518
 519         event->hw.config = ppmu->xlate_event(ev);
 520         if (!(event->hw.config & FSL_EMB_EVENT_VALID))
 521                 return -EINVAL;
 522
 523         /*
 524          * If this is in a group, check if it can go on with all the
 525          * other hardware events in the group.  We assume the event
 526          * hasn't been linked into its leader's sibling list at this point.
 527          */
 528         n = 0;
 529         if (event->group_leader != event) {
 530                 n = collect_events(event->group_leader,
 531                                    ppmu->n_counter - 1, events);
 532                 if (n < 0)
 533                         return -EINVAL;
 534         }
 535
 536         if (event->hw.config & FSL_EMB_EVENT_RESTRICTED) {
 537                 num_restricted = 0;
 538                 for (i = 0; i < n; i++) {
 539                         if (events[i]->hw.config & FSL_EMB_EVENT_RESTRICTED)
 540                                 num_restricted++;
 541                 }
 542
 543                 if (num_restricted >= ppmu->n_restricted)
 544                         return -EINVAL;
 545         }
 546
 547         event->hw.idx = -1;
 548
 549         event->hw.config_base = PMLCA_CE | PMLCA_FCM1 |
 550                                 (u32)((ev << 16) & PMLCA_EVENT_MASK);
 551
 552         if (event->attr.exclude_user)
 553                 event->hw.config_base |= PMLCA_FCU;
 554         if (event->attr.exclude_kernel)
 555                 event->hw.config_base |= PMLCA_FCS;
 556         if (event->attr.exclude_idle)
 557                 return -ENOTSUPP;
 558
 559         event->hw.last_period = event->hw.sample_period;
 560         local64_set(&event->hw.period_left, event->hw.last_period);
 561
 562         /*
 563          * See if we need to reserve the PMU.
 564          * If no events are currently in use, then we have to take a
 565          * mutex to ensure that we don't race with another task doing
 566          * reserve_pmc_hardware or release_pmc_hardware.
 567          */
 568         err = 0;
 569         if (!atomic_inc_not_zero(&num_events)) {
 570                 mutex_lock(&pmc_reserve_mutex);
 571                 if (atomic_read(&num_events) == 0 &&
 572                     reserve_pmc_hardware(perf_event_interrupt))
 573                         err = -EBUSY;
 574                 else
 575                         atomic_inc(&num_events);
 576                 mutex_unlock(&pmc_reserve_mutex);
 577
 578                 mtpmr(PMRN_PMGC0, PMGC0_FAC);
 579                 isync();
 580         }
 581         event->destroy = hw_perf_event_destroy;
 582
 583         return err;
 584 }
 585
 586 static struct pmu fsl_emb_pmu = {
 587         .pmu_enable     = fsl_emb_pmu_enable,
 588         .pmu_disable    = fsl_emb_pmu_disable,
 589         .event_init     = fsl_emb_pmu_event_init,
 590         .add            = fsl_emb_pmu_add,
 591         .del            = fsl_emb_pmu_del,
 592         .start          = fsl_emb_pmu_start,
 593         .stop           = fsl_emb_pmu_stop,
 594         .read           = fsl_emb_pmu_read,
 595 };
 596
 597 /*
 598  * A counter has overflowed; update its count and record
 599  * things if requested.  Note that interrupts are hard-disabled
 600  * here so there is no possibility of being interrupted.
 601  */
 602 static void record_and_restart(struct perf_event *event, unsigned long val,
 603                                struct pt_regs *regs)
 604 {
 605         u64 period = event->hw.sample_period;
 606         s64 prev, delta, left;
 607         int record = 0;
 608
 609         if (event->hw.state & PERF_HES_STOPPED) {
 610                 write_pmc(event->hw.idx, 0);
 611                 return;
 612         }
 613
 614         /* we don't have to worry about interrupts here */
 615         prev = local64_read(&event->hw.prev_count);
 616         delta = (val - prev) & 0xfffffffful;
 617         local64_add(delta, &event->count);
 618
 619         /*
 620          * See if the total period for this event has expired,
 621          * and update for the next period.
 622          */
 623         val = 0;
 624         left = local64_read(&event->hw.period_left) - delta;
 625         if (period) {
 626                 if (left <= 0) {
 627                         left += period;
 628                         if (left <= 0)
 629                                 left = period;
 630                         record = 1;
 631                         event->hw.last_period = event->hw.sample_period;
 632                 }
 633                 if (left < 0x80000000LL)
 634                         val = 0x80000000LL - left;
 635         }
 636
 637         write_pmc(event->hw.idx, val);
 638         local64_set(&event->hw.prev_count, val);
 639         local64_set(&event->hw.period_left, left);
 640         perf_event_update_userpage(event);
 641
 642         /*
 643          * Finally record data if requested.
 644          */
 645         if (record) {
 646                 struct perf_sample_data data;
 647
 648                 perf_sample_data_init(&data, 0, event->hw.last_period);
 649
 650                 if (perf_event_overflow(event, &data, regs))
 651                         fsl_emb_pmu_stop(event, 0);
 652         }
 653 }
 654
 655 static void perf_event_interrupt(struct pt_regs *regs)
 656 {
 657         int i;
 658         struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
 659         struct perf_event *event;
 660         unsigned long val;
 661         int found = 0;
 662         int nmi;
 663
 664         nmi = perf_intr_is_nmi(regs);
 665         if (nmi)
 666                 nmi_enter();
 667         else
 668                 irq_enter();
 669
 670         for (i = 0; i < ppmu->n_counter; ++i) {
 671                 event = cpuhw->event[i];
 672
 673                 val = read_pmc(i);
 674                 if ((int)val < 0) {
 675                         if (event) {
 676                                 /* event has overflowed */
 677                                 found = 1;
 678                                 record_and_restart(event, val, regs);
 679                         } else {
 680                                 /*
 681                                  * Disabled counter is negative,
 682                                  * reset it just in case.
 683                                  */
 684                                 write_pmc(i, 0);
 685                         }
 686                 }
 687         }
 688
 689         /* PMM will keep counters frozen until we return from the interrupt. */
 690         mtmsr(mfmsr() | MSR_PMM);
 691         mtpmr(PMRN_PMGC0, PMGC0_PMIE | PMGC0_FCECE);
 692         isync();
 693
 694         if (nmi)
 695                 nmi_exit();
 696         else
 697                 irq_exit();
 698 }
 699
 700 void hw_perf_event_setup(int cpu)
 701 {
 702         struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
 703
 704         memset(cpuhw, 0, sizeof(*cpuhw));
 705 }
 706
 707 int register_fsl_emb_pmu(struct fsl_emb_pmu *pmu)
 708 {
 709         if (ppmu)
 710                 return -EBUSY;          /* something's already registered */
 711
 712         ppmu = pmu;
 713         pr_info("%s performance monitor hardware support registered\n",
 714                 pmu->name);
 715
 716         perf_pmu_register(&fsl_emb_pmu, "cpu", PERF_TYPE_RAW);
 717
 718         return 0;
 719 }