arch/powerpc/kernel/perf_event_fsl_emb.c

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