arch/arc/kernel/perf_event.c

   1 /*
   2  * Linux performance counter support for ARC700 series
   3  *
   4  * Copyright (C) 2013-2015 Synopsys, Inc. (www.synopsys.com)
   5  *
   6  * This code is inspired by the perf support of various other architectures.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13 #include <linux/errno.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/perf_event.h>
  18 #include <linux/platform_device.h>
  19 #include <asm/arcregs.h>
  20 #include <asm/stacktrace.h>
  21
  22 struct arc_pmu {
  23         struct pmu      pmu;
  24         unsigned int    irq;
  25         int             n_counters;
  26         u64             max_period;
  27         int             ev_hw_idx[PERF_COUNT_ARC_HW_MAX];
  28 };
  29
  30 struct arc_pmu_cpu {
  31         /*
  32          * A 1 bit for an index indicates that the counter is being used for
  33          * an event. A 0 means that the counter can be used.
  34          */
  35         unsigned long   used_mask[BITS_TO_LONGS(ARC_PERF_MAX_COUNTERS)];
  36
  37         /*
  38          * The events that are active on the PMU for the given index.
  39          */
  40         struct perf_event *act_counter[ARC_PERF_MAX_COUNTERS];
  41 };
  42
  43 struct arc_callchain_trace {
  44         int depth;
  45         void *perf_stuff;
  46 };
  47
  48 static int callchain_trace(unsigned int addr, void *data)
  49 {
  50         struct arc_callchain_trace *ctrl = data;
  51         struct perf_callchain_entry_ctx *entry = ctrl->perf_stuff;
  52         perf_callchain_store(entry, addr);
  53
  54         if (ctrl->depth++ < 3)
  55                 return 0;
  56
  57         return -1;
  58 }
  59
  60 void
  61 perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
  62 {
  63         struct arc_callchain_trace ctrl = {
  64                 .depth = 0,
  65                 .perf_stuff = entry,
  66         };
  67
  68         arc_unwind_core(NULL, regs, callchain_trace, &ctrl);
  69 }
  70
  71 void
  72 perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
  73 {
  74         /*
  75          * User stack can't be unwound trivially with kernel dwarf unwinder
  76          * So for now just record the user PC
  77          */
  78         perf_callchain_store(entry, instruction_pointer(regs));
  79 }
  80
  81 static struct arc_pmu *arc_pmu;
  82 static DEFINE_PER_CPU(struct arc_pmu_cpu, arc_pmu_cpu);
  83
  84 /* read counter #idx; note that counter# != event# on ARC! */
  85 static uint64_t arc_pmu_read_counter(int idx)
  86 {
  87         uint32_t tmp;
  88         uint64_t result;
  89
  90         /*
  91          * ARC supports making 'snapshots' of the counters, so we don't
  92          * need to care about counters wrapping to 0 underneath our feet
  93          */
  94         write_aux_reg(ARC_REG_PCT_INDEX, idx);
  95         tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
  96         write_aux_reg(ARC_REG_PCT_CONTROL, tmp | ARC_REG_PCT_CONTROL_SN);
  97         result = (uint64_t) (read_aux_reg(ARC_REG_PCT_SNAPH)) << 32;
  98         result |= read_aux_reg(ARC_REG_PCT_SNAPL);
  99
 100         return result;
 101 }
 102
 103 static void arc_perf_event_update(struct perf_event *event,
 104                                   struct hw_perf_event *hwc, int idx)
 105 {
 106         uint64_t prev_raw_count = local64_read(&hwc->prev_count);
 107         uint64_t new_raw_count = arc_pmu_read_counter(idx);
 108         int64_t delta = new_raw_count - prev_raw_count;
 109
 110         /*
 111          * We aren't afraid of hwc->prev_count changing beneath our feet
 112          * because there's no way for us to re-enter this function anytime.
 113          */
 114         local64_set(&hwc->prev_count, new_raw_count);
 115         local64_add(delta, &event->count);
 116         local64_sub(delta, &hwc->period_left);
 117 }
 118
 119 static void arc_pmu_read(struct perf_event *event)
 120 {
 121         arc_perf_event_update(event, &event->hw, event->hw.idx);
 122 }
 123
 124 static int arc_pmu_cache_event(u64 config)
 125 {
 126         unsigned int cache_type, cache_op, cache_result;
 127         int ret;
 128
 129         cache_type      = (config >>  0) & 0xff;
 130         cache_op        = (config >>  8) & 0xff;
 131         cache_result    = (config >> 16) & 0xff;
 132         if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
 133                 return -EINVAL;
 134         if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
 135                 return -EINVAL;
 136         if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
 137                 return -EINVAL;
 138
 139         ret = arc_pmu_cache_map[cache_type][cache_op][cache_result];
 140
 141         if (ret == CACHE_OP_UNSUPPORTED)
 142                 return -ENOENT;
 143
 144         pr_debug("init cache event: type/op/result %d/%d/%d with h/w %d \'%s\'\n",
 145                  cache_type, cache_op, cache_result, ret,
 146                  arc_pmu_ev_hw_map[ret]);
 147
 148         return ret;
 149 }
 150
 151 /* initializes hw_perf_event structure if event is supported */
 152 static int arc_pmu_event_init(struct perf_event *event)
 153 {
 154         struct hw_perf_event *hwc = &event->hw;
 155         int ret;
 156
 157         if (!is_sampling_event(event)) {
 158                 hwc->sample_period  = arc_pmu->max_period;
 159                 hwc->last_period = hwc->sample_period;
 160                 local64_set(&hwc->period_left, hwc->sample_period);
 161         }
 162
 163         hwc->config = 0;
 164
 165         if (is_isa_arcv2()) {
 166                 /* "exclude user" means "count only kernel" */
 167                 if (event->attr.exclude_user)
 168                         hwc->config |= ARC_REG_PCT_CONFIG_KERN;
 169
 170                 /* "exclude kernel" means "count only user" */
 171                 if (event->attr.exclude_kernel)
 172                         hwc->config |= ARC_REG_PCT_CONFIG_USER;
 173         }
 174
 175         switch (event->attr.type) {
 176         case PERF_TYPE_HARDWARE:
 177                 if (event->attr.config >= PERF_COUNT_HW_MAX)
 178                         return -ENOENT;
 179                 if (arc_pmu->ev_hw_idx[event->attr.config] < 0)
 180                         return -ENOENT;
 181                 hwc->config |= arc_pmu->ev_hw_idx[event->attr.config];
 182                 pr_debug("init event %d with h/w %08x \'%s\'\n",
 183                          (int)event->attr.config, (int)hwc->config,
 184                          arc_pmu_ev_hw_map[event->attr.config]);
 185                 return 0;
 186
 187         case PERF_TYPE_HW_CACHE:
 188                 ret = arc_pmu_cache_event(event->attr.config);
 189                 if (ret < 0)
 190                         return ret;
 191                 hwc->config |= arc_pmu->ev_hw_idx[ret];
 192                 pr_debug("init cache event with h/w %08x \'%s\'\n",
 193                          (int)hwc->config, arc_pmu_ev_hw_map[ret]);
 194                 return 0;
 195         default:
 196                 return -ENOENT;
 197         }
 198 }
 199
 200 /* starts all counters */
 201 static void arc_pmu_enable(struct pmu *pmu)
 202 {
 203         uint32_t tmp;
 204         tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
 205         write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x1);
 206 }
 207
 208 /* stops all counters */
 209 static void arc_pmu_disable(struct pmu *pmu)
 210 {
 211         uint32_t tmp;
 212         tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
 213         write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x0);
 214 }
 215
 216 static int arc_pmu_event_set_period(struct perf_event *event)
 217 {
 218         struct hw_perf_event *hwc = &event->hw;
 219         s64 left = local64_read(&hwc->period_left);
 220         s64 period = hwc->sample_period;
 221         int idx = hwc->idx;
 222         int overflow = 0;
 223         u64 value;
 224
 225         if (unlikely(left <= -period)) {
 226                 /* left underflowed by more than period. */
 227                 left = period;
 228                 local64_set(&hwc->period_left, left);
 229                 hwc->last_period = period;
 230                 overflow = 1;
 231         } else  if (unlikely(left <= 0)) {
 232                 /* left underflowed by less than period. */
 233                 left += period;
 234                 local64_set(&hwc->period_left, left);
 235                 hwc->last_period = period;
 236                 overflow = 1;
 237         }
 238
 239         if (left > arc_pmu->max_period)
 240                 left = arc_pmu->max_period;
 241
 242         value = arc_pmu->max_period - left;
 243         local64_set(&hwc->prev_count, value);
 244
 245         /* Select counter */
 246         write_aux_reg(ARC_REG_PCT_INDEX, idx);
 247
 248         /* Write value */
 249         write_aux_reg(ARC_REG_PCT_COUNTL, (u32)value);
 250         write_aux_reg(ARC_REG_PCT_COUNTH, (value >> 32));
 251
 252         perf_event_update_userpage(event);
 253
 254         return overflow;
 255 }
 256
 257 /*
 258  * Assigns hardware counter to hardware condition.
 259  * Note that there is no separate start/stop mechanism;
 260  * stopping is achieved by assigning the 'never' condition
 261  */
 262 static void arc_pmu_start(struct perf_event *event, int flags)
 263 {
 264         struct hw_perf_event *hwc = &event->hw;
 265         int idx = hwc->idx;
 266
 267         if (WARN_ON_ONCE(idx == -1))
 268                 return;
 269
 270         if (flags & PERF_EF_RELOAD)
 271                 WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
 272
 273         hwc->state = 0;
 274
 275         arc_pmu_event_set_period(event);
 276
 277         /* Enable interrupt for this counter */
 278         if (is_sampling_event(event))
 279                 write_aux_reg(ARC_REG_PCT_INT_CTRL,
 280                               read_aux_reg(ARC_REG_PCT_INT_CTRL) | (1 << idx));
 281
 282         /* enable ARC pmu here */
 283         write_aux_reg(ARC_REG_PCT_INDEX, idx);          /* counter # */
 284         write_aux_reg(ARC_REG_PCT_CONFIG, hwc->config); /* condition */
 285 }
 286
 287 static void arc_pmu_stop(struct perf_event *event, int flags)
 288 {
 289         struct hw_perf_event *hwc = &event->hw;
 290         int idx = hwc->idx;
 291
 292         /* Disable interrupt for this counter */
 293         if (is_sampling_event(event)) {
 294                 /*
 295                  * Reset interrupt flag by writing of 1. This is required
 296                  * to make sure pending interrupt was not left.
 297                  */
 298                 write_aux_reg(ARC_REG_PCT_INT_ACT, 1 << idx);
 299                 write_aux_reg(ARC_REG_PCT_INT_CTRL,
 300                               read_aux_reg(ARC_REG_PCT_INT_CTRL) & ~(1 << idx));
 301         }
 302
 303         if (!(event->hw.state & PERF_HES_STOPPED)) {
 304                 /* stop ARC pmu here */
 305                 write_aux_reg(ARC_REG_PCT_INDEX, idx);
 306
 307                 /* condition code #0 is always "never" */
 308                 write_aux_reg(ARC_REG_PCT_CONFIG, 0);
 309
 310                 event->hw.state |= PERF_HES_STOPPED;
 311         }
 312
 313         if ((flags & PERF_EF_UPDATE) &&
 314             !(event->hw.state & PERF_HES_UPTODATE)) {
 315                 arc_perf_event_update(event, &event->hw, idx);
 316                 event->hw.state |= PERF_HES_UPTODATE;
 317         }
 318 }
 319
 320 static void arc_pmu_del(struct perf_event *event, int flags)
 321 {
 322         struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
 323
 324         arc_pmu_stop(event, PERF_EF_UPDATE);
 325         __clear_bit(event->hw.idx, pmu_cpu->used_mask);
 326
 327         pmu_cpu->act_counter[event->hw.idx] = 0;
 328
 329         perf_event_update_userpage(event);
 330 }
 331
 332 /* allocate hardware counter and optionally start counting */
 333 static int arc_pmu_add(struct perf_event *event, int flags)
 334 {
 335         struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
 336         struct hw_perf_event *hwc = &event->hw;
 337         int idx = hwc->idx;
 338
 339         if (__test_and_set_bit(idx, pmu_cpu->used_mask)) {
 340                 idx = find_first_zero_bit(pmu_cpu->used_mask,
 341                                           arc_pmu->n_counters);
 342                 if (idx == arc_pmu->n_counters)
 343                         return -EAGAIN;
 344
 345                 __set_bit(idx, pmu_cpu->used_mask);
 346                 hwc->idx = idx;
 347         }
 348
 349         write_aux_reg(ARC_REG_PCT_INDEX, idx);
 350
 351         pmu_cpu->act_counter[idx] = event;
 352
 353         if (is_sampling_event(event)) {
 354                 /* Mimic full counter overflow as other arches do */
 355                 write_aux_reg(ARC_REG_PCT_INT_CNTL, (u32)arc_pmu->max_period);
 356                 write_aux_reg(ARC_REG_PCT_INT_CNTH,
 357                               (arc_pmu->max_period >> 32));
 358         }
 359
 360         write_aux_reg(ARC_REG_PCT_CONFIG, 0);
 361         write_aux_reg(ARC_REG_PCT_COUNTL, 0);
 362         write_aux_reg(ARC_REG_PCT_COUNTH, 0);
 363         local64_set(&hwc->prev_count, 0);
 364
 365         hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
 366         if (flags & PERF_EF_START)
 367                 arc_pmu_start(event, PERF_EF_RELOAD);
 368
 369         perf_event_update_userpage(event);
 370
 371         return 0;
 372 }
 373
 374 #ifdef CONFIG_ISA_ARCV2
 375 static irqreturn_t arc_pmu_intr(int irq, void *dev)
 376 {
 377         struct perf_sample_data data;
 378         struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
 379         struct pt_regs *regs;
 380         int active_ints;
 381         int idx;
 382
 383         arc_pmu_disable(&arc_pmu->pmu);
 384
 385         active_ints = read_aux_reg(ARC_REG_PCT_INT_ACT);
 386
 387         regs = get_irq_regs();
 388
 389         for (idx = 0; idx < arc_pmu->n_counters; idx++) {
 390                 struct perf_event *event = pmu_cpu->act_counter[idx];
 391                 struct hw_perf_event *hwc;
 392
 393                 if (!(active_ints & (1 << idx)))
 394                         continue;
 395
 396                 /* Reset interrupt flag by writing of 1 */
 397                 write_aux_reg(ARC_REG_PCT_INT_ACT, 1 << idx);
 398
 399                 /*
 400                  * On reset of "interrupt active" bit corresponding
 401                  * "interrupt enable" bit gets automatically reset as well.
 402                  * Now we need to re-enable interrupt for the counter.
 403                  */
 404                 write_aux_reg(ARC_REG_PCT_INT_CTRL,
 405                         read_aux_reg(ARC_REG_PCT_INT_CTRL) | (1 << idx));
 406
 407                 hwc = &event->hw;
 408
 409                 WARN_ON_ONCE(hwc->idx != idx);
 410
 411                 arc_perf_event_update(event, &event->hw, event->hw.idx);
 412                 perf_sample_data_init(&data, 0, hwc->last_period);
 413                 if (!arc_pmu_event_set_period(event))
 414                         continue;
 415
 416                 if (perf_event_overflow(event, &data, regs))
 417                         arc_pmu_stop(event, 0);
 418         }
 419
 420         arc_pmu_enable(&arc_pmu->pmu);
 421
 422         return IRQ_HANDLED;
 423 }
 424 #else
 425
 426 static irqreturn_t arc_pmu_intr(int irq, void *dev)
 427 {
 428         return IRQ_NONE;
 429 }
 430
 431 #endif /* CONFIG_ISA_ARCV2 */
 432
 433 static void arc_cpu_pmu_irq_init(void *data)
 434 {
 435         int irq = *(int *)data;
 436
 437         enable_percpu_irq(irq, IRQ_TYPE_NONE);
 438
 439         /* Clear all pending interrupt flags */
 440         write_aux_reg(ARC_REG_PCT_INT_ACT, 0xffffffff);
 441 }
 442
 443 static int arc_pmu_device_probe(struct platform_device *pdev)
 444 {
 445         struct arc_reg_pct_build pct_bcr;
 446         struct arc_reg_cc_build cc_bcr;
 447         int i, j, has_interrupts;
 448         int counter_size;       /* in bits */
 449
 450         union cc_name {
 451                 struct {
 452                         uint32_t word0, word1;
 453                         char sentinel;
 454                 } indiv;
 455                 char str[9];
 456         } cc_name;
 457
 458
 459         READ_BCR(ARC_REG_PCT_BUILD, pct_bcr);
 460         if (!pct_bcr.v) {
 461                 pr_err("This core does not have performance counters!\n");
 462                 return -ENODEV;
 463         }
 464         BUG_ON(pct_bcr.c > ARC_PERF_MAX_COUNTERS);
 465
 466         READ_BCR(ARC_REG_CC_BUILD, cc_bcr);
 467         BUG_ON(!cc_bcr.v); /* Counters exist but No countable conditions ? */
 468
 469         arc_pmu = devm_kzalloc(&pdev->dev, sizeof(struct arc_pmu), GFP_KERNEL);
 470         if (!arc_pmu)
 471                 return -ENOMEM;
 472
 473         has_interrupts = is_isa_arcv2() ? pct_bcr.i : 0;
 474
 475         arc_pmu->n_counters = pct_bcr.c;
 476         counter_size = 32 + (pct_bcr.s << 4);
 477
 478         arc_pmu->max_period = (1ULL << counter_size) / 2 - 1ULL;
 479
 480         pr_info("ARC perf\t: %d counters (%d bits), %d conditions%s\n",
 481                 arc_pmu->n_counters, counter_size, cc_bcr.c,
 482                 has_interrupts ? ", [overflow IRQ support]":"");
 483
 484         cc_name.str[8] = 0;
 485         for (i = 0; i < PERF_COUNT_ARC_HW_MAX; i++)
 486                 arc_pmu->ev_hw_idx[i] = -1;
 487
 488         /* loop thru all available h/w condition indexes */
 489         for (j = 0; j < cc_bcr.c; j++) {
 490                 write_aux_reg(ARC_REG_CC_INDEX, j);
 491                 cc_name.indiv.word0 = le32_to_cpu(read_aux_reg(ARC_REG_CC_NAME0));
 492                 cc_name.indiv.word1 = le32_to_cpu(read_aux_reg(ARC_REG_CC_NAME1));
 493
 494                 /* See if it has been mapped to a perf event_id */
 495                 for (i = 0; i < ARRAY_SIZE(arc_pmu_ev_hw_map); i++) {
 496                         if (arc_pmu_ev_hw_map[i] &&
 497                             !strcmp(arc_pmu_ev_hw_map[i], cc_name.str) &&
 498                             strlen(arc_pmu_ev_hw_map[i])) {
 499                                 pr_debug("mapping perf event %2d to h/w event \'%8s\' (idx %d)\n",
 500                                          i, cc_name.str, j);
 501                                 arc_pmu->ev_hw_idx[i] = j;
 502                         }
 503                 }
 504         }
 505
 506         arc_pmu->pmu = (struct pmu) {
 507                 .pmu_enable     = arc_pmu_enable,
 508                 .pmu_disable    = arc_pmu_disable,
 509                 .event_init     = arc_pmu_event_init,
 510                 .add            = arc_pmu_add,
 511                 .del            = arc_pmu_del,
 512                 .start          = arc_pmu_start,
 513                 .stop           = arc_pmu_stop,
 514                 .read           = arc_pmu_read,
 515         };
 516
 517         if (has_interrupts) {
 518                 int irq = platform_get_irq(pdev, 0);
 519
 520                 if (irq < 0) {
 521                         pr_err("Cannot get IRQ number for the platform\n");
 522                         return -ENODEV;
 523                 }
 524
 525                 arc_pmu->irq = irq;
 526
 527                 /* intc map function ensures irq_set_percpu_devid() called */
 528                 request_percpu_irq(irq, arc_pmu_intr, "ARC perf counters",
 529                                    this_cpu_ptr(&arc_pmu_cpu));
 530
 531                 on_each_cpu(arc_cpu_pmu_irq_init, &irq, 1);
 532
 533         } else
 534                 arc_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 535
 536         return perf_pmu_register(&arc_pmu->pmu, pdev->name, PERF_TYPE_RAW);
 537 }
 538
 539 #ifdef CONFIG_OF
 540 static const struct of_device_id arc_pmu_match[] = {
 541         { .compatible = "snps,arc700-pct" },
 542         { .compatible = "snps,archs-pct" },
 543         {},
 544 };
 545 MODULE_DEVICE_TABLE(of, arc_pmu_match);
 546 #endif
 547
 548 static struct platform_driver arc_pmu_driver = {
 549         .driver = {
 550                 .name           = "arc-pct",
 551                 .of_match_table = of_match_ptr(arc_pmu_match),
 552         },
 553         .probe          = arc_pmu_device_probe,
 554 };
 555
 556 module_platform_driver(arc_pmu_driver);
 557
 558 MODULE_LICENSE("GPL");
 559 MODULE_AUTHOR("Mischa Jonker <mjonker@synopsys.com>");
 560 MODULE_DESCRIPTION("ARC PMU driver");