tools/perf/arch/x86/util/intel-pt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * intel_pt.c: Intel Processor Trace support
   4  * Copyright (c) 2013-2015, Intel Corporation.
   5  */
   6
   7 #include <errno.h>
   8 #include <stdbool.h>
   9 #include <linux/kernel.h>
  10 #include <linux/types.h>
  11 #include <linux/bitops.h>
  12 #include <linux/log2.h>
  13 #include <cpuid.h>
  14
  15 #include "../../perf.h"
  16 #include "../../util/session.h"
  17 #include "../../util/event.h"
  18 #include "../../util/evlist.h"
  19 #include "../../util/evsel.h"
  20 #include "../../util/cpumap.h"
  21 #include <subcmd/parse-options.h>
  22 #include "../../util/parse-events.h"
  23 #include "../../util/pmu.h"
  24 #include "../../util/debug.h"
  25 #include "../../util/auxtrace.h"
  26 #include "../../util/tsc.h"
  27 #include "../../util/intel-pt.h"
  28
  29 #define KiB(x) ((x) * 1024)
  30 #define MiB(x) ((x) * 1024 * 1024)
  31 #define KiB_MASK(x) (KiB(x) - 1)
  32 #define MiB_MASK(x) (MiB(x) - 1)
  33
  34 #define INTEL_PT_PSB_PERIOD_NEAR        256
  35
  36 struct intel_pt_snapshot_ref {
  37         void *ref_buf;
  38         size_t ref_offset;
  39         bool wrapped;
  40 };
  41
  42 struct intel_pt_recording {
  43         struct auxtrace_record          itr;
  44         struct perf_pmu                 *intel_pt_pmu;
  45         int                             have_sched_switch;
  46         struct perf_evlist              *evlist;
  47         bool                            snapshot_mode;
  48         bool                            snapshot_init_done;
  49         size_t                          snapshot_size;
  50         size_t                          snapshot_ref_buf_size;
  51         int                             snapshot_ref_cnt;
  52         struct intel_pt_snapshot_ref    *snapshot_refs;
  53         size_t                          priv_size;
  54 };
  55
  56 static int intel_pt_parse_terms_with_default(struct list_head *formats,
  57                                              const char *str,
  58                                              u64 *config)
  59 {
  60         struct list_head *terms;
  61         struct perf_event_attr attr = { .size = 0, };
  62         int err;
  63
  64         terms = malloc(sizeof(struct list_head));
  65         if (!terms)
  66                 return -ENOMEM;
  67
  68         INIT_LIST_HEAD(terms);
  69
  70         err = parse_events_terms(terms, str);
  71         if (err)
  72                 goto out_free;
  73
  74         attr.config = *config;
  75         err = perf_pmu__config_terms(formats, &attr, terms, true, NULL);
  76         if (err)
  77                 goto out_free;
  78
  79         *config = attr.config;
  80 out_free:
  81         parse_events_terms__delete(terms);
  82         return err;
  83 }
  84
  85 static int intel_pt_parse_terms(struct list_head *formats, const char *str,
  86                                 u64 *config)
  87 {
  88         *config = 0;
  89         return intel_pt_parse_terms_with_default(formats, str, config);
  90 }
  91
  92 static u64 intel_pt_masked_bits(u64 mask, u64 bits)
  93 {
  94         const u64 top_bit = 1ULL << 63;
  95         u64 res = 0;
  96         int i;
  97
  98         for (i = 0; i < 64; i++) {
  99                 if (mask & top_bit) {
 100                         res <<= 1;
 101                         if (bits & top_bit)
 102                                 res |= 1;
 103                 }
 104                 mask <<= 1;
 105                 bits <<= 1;
 106         }
 107
 108         return res;
 109 }
 110
 111 static int intel_pt_read_config(struct perf_pmu *intel_pt_pmu, const char *str,
 112                                 struct perf_evlist *evlist, u64 *res)
 113 {
 114         struct perf_evsel *evsel;
 115         u64 mask;
 116
 117         *res = 0;
 118
 119         mask = perf_pmu__format_bits(&intel_pt_pmu->format, str);
 120         if (!mask)
 121                 return -EINVAL;
 122
 123         evlist__for_each_entry(evlist, evsel) {
 124                 if (evsel->attr.type == intel_pt_pmu->type) {
 125                         *res = intel_pt_masked_bits(mask, evsel->attr.config);
 126                         return 0;
 127                 }
 128         }
 129
 130         return -EINVAL;
 131 }
 132
 133 static size_t intel_pt_psb_period(struct perf_pmu *intel_pt_pmu,
 134                                   struct perf_evlist *evlist)
 135 {
 136         u64 val;
 137         int err, topa_multiple_entries;
 138         size_t psb_period;
 139
 140         if (perf_pmu__scan_file(intel_pt_pmu, "caps/topa_multiple_entries",
 141                                 "%d", &topa_multiple_entries) != 1)
 142                 topa_multiple_entries = 0;
 143
 144         /*
 145          * Use caps/topa_multiple_entries to indicate early hardware that had
 146          * extra frequent PSBs.
 147          */
 148         if (!topa_multiple_entries) {
 149                 psb_period = 256;
 150                 goto out;
 151         }
 152
 153         err = intel_pt_read_config(intel_pt_pmu, "psb_period", evlist, &val);
 154         if (err)
 155                 val = 0;
 156
 157         psb_period = 1 << (val + 11);
 158 out:
 159         pr_debug2("%s psb_period %zu\n", intel_pt_pmu->name, psb_period);
 160         return psb_period;
 161 }
 162
 163 static int intel_pt_pick_bit(int bits, int target)
 164 {
 165         int pos, pick = -1;
 166
 167         for (pos = 0; bits; bits >>= 1, pos++) {
 168                 if (bits & 1) {
 169                         if (pos <= target || pick < 0)
 170                                 pick = pos;
 171                         if (pos >= target)
 172                                 break;
 173                 }
 174         }
 175
 176         return pick;
 177 }
 178
 179 static u64 intel_pt_default_config(struct perf_pmu *intel_pt_pmu)
 180 {
 181         char buf[256];
 182         int mtc, mtc_periods = 0, mtc_period;
 183         int psb_cyc, psb_periods, psb_period;
 184         int pos = 0;
 185         u64 config;
 186         char c;
 187
 188         pos += scnprintf(buf + pos, sizeof(buf) - pos, "tsc");
 189
 190         if (perf_pmu__scan_file(intel_pt_pmu, "caps/mtc", "%d",
 191                                 &mtc) != 1)
 192                 mtc = 1;
 193
 194         if (mtc) {
 195                 if (perf_pmu__scan_file(intel_pt_pmu, "caps/mtc_periods", "%x",
 196                                         &mtc_periods) != 1)
 197                         mtc_periods = 0;
 198                 if (mtc_periods) {
 199                         mtc_period = intel_pt_pick_bit(mtc_periods, 3);
 200                         pos += scnprintf(buf + pos, sizeof(buf) - pos,
 201                                          ",mtc,mtc_period=%d", mtc_period);
 202                 }
 203         }
 204
 205         if (perf_pmu__scan_file(intel_pt_pmu, "caps/psb_cyc", "%d",
 206                                 &psb_cyc) != 1)
 207                 psb_cyc = 1;
 208
 209         if (psb_cyc && mtc_periods) {
 210                 if (perf_pmu__scan_file(intel_pt_pmu, "caps/psb_periods", "%x",
 211                                         &psb_periods) != 1)
 212                         psb_periods = 0;
 213                 if (psb_periods) {
 214                         psb_period = intel_pt_pick_bit(psb_periods, 3);
 215                         pos += scnprintf(buf + pos, sizeof(buf) - pos,
 216                                          ",psb_period=%d", psb_period);
 217                 }
 218         }
 219
 220         if (perf_pmu__scan_file(intel_pt_pmu, "format/pt", "%c", &c) == 1 &&
 221             perf_pmu__scan_file(intel_pt_pmu, "format/branch", "%c", &c) == 1)
 222                 pos += scnprintf(buf + pos, sizeof(buf) - pos, ",pt,branch");
 223
 224         pr_debug2("%s default config: %s\n", intel_pt_pmu->name, buf);
 225
 226         intel_pt_parse_terms(&intel_pt_pmu->format, buf, &config);
 227
 228         return config;
 229 }
 230
 231 static int intel_pt_parse_snapshot_options(struct auxtrace_record *itr,
 232                                            struct record_opts *opts,
 233                                            const char *str)
 234 {
 235         struct intel_pt_recording *ptr =
 236                         container_of(itr, struct intel_pt_recording, itr);
 237         unsigned long long snapshot_size = 0;
 238         char *endptr;
 239
 240         if (str) {
 241                 snapshot_size = strtoull(str, &endptr, 0);
 242                 if (*endptr || snapshot_size > SIZE_MAX)
 243                         return -1;
 244         }
 245
 246         opts->auxtrace_snapshot_mode = true;
 247         opts->auxtrace_snapshot_size = snapshot_size;
 248
 249         ptr->snapshot_size = snapshot_size;
 250
 251         return 0;
 252 }
 253
 254 struct perf_event_attr *
 255 intel_pt_pmu_default_config(struct perf_pmu *intel_pt_pmu)
 256 {
 257         struct perf_event_attr *attr;
 258
 259         attr = zalloc(sizeof(struct perf_event_attr));
 260         if (!attr)
 261                 return NULL;
 262
 263         attr->config = intel_pt_default_config(intel_pt_pmu);
 264
 265         intel_pt_pmu->selectable = true;
 266
 267         return attr;
 268 }
 269
 270 static const char *intel_pt_find_filter(struct perf_evlist *evlist,
 271                                         struct perf_pmu *intel_pt_pmu)
 272 {
 273         struct perf_evsel *evsel;
 274
 275         evlist__for_each_entry(evlist, evsel) {
 276                 if (evsel->attr.type == intel_pt_pmu->type)
 277                         return evsel->filter;
 278         }
 279
 280         return NULL;
 281 }
 282
 283 static size_t intel_pt_filter_bytes(const char *filter)
 284 {
 285         size_t len = filter ? strlen(filter) : 0;
 286
 287         return len ? roundup(len + 1, 8) : 0;
 288 }
 289
 290 static size_t
 291 intel_pt_info_priv_size(struct auxtrace_record *itr, struct perf_evlist *evlist)
 292 {
 293         struct intel_pt_recording *ptr =
 294                         container_of(itr, struct intel_pt_recording, itr);
 295         const char *filter = intel_pt_find_filter(evlist, ptr->intel_pt_pmu);
 296
 297         ptr->priv_size = (INTEL_PT_AUXTRACE_PRIV_MAX * sizeof(u64)) +
 298                          intel_pt_filter_bytes(filter);
 299
 300         return ptr->priv_size;
 301 }
 302
 303 static void intel_pt_tsc_ctc_ratio(u32 *n, u32 *d)
 304 {
 305         unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0;
 306
 307         __get_cpuid(0x15, &eax, &ebx, &ecx, &edx);
 308         *n = ebx;
 309         *d = eax;
 310 }
 311
 312 static int intel_pt_info_fill(struct auxtrace_record *itr,
 313                               struct perf_session *session,
 314                               struct auxtrace_info_event *auxtrace_info,
 315                               size_t priv_size)
 316 {
 317         struct intel_pt_recording *ptr =
 318                         container_of(itr, struct intel_pt_recording, itr);
 319         struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
 320         struct perf_event_mmap_page *pc;
 321         struct perf_tsc_conversion tc = { .time_mult = 0, };
 322         bool cap_user_time_zero = false, per_cpu_mmaps;
 323         u64 tsc_bit, mtc_bit, mtc_freq_bits, cyc_bit, noretcomp_bit;
 324         u32 tsc_ctc_ratio_n, tsc_ctc_ratio_d;
 325         unsigned long max_non_turbo_ratio;
 326         size_t filter_str_len;
 327         const char *filter;
 328         u64 *info;
 329         int err;
 330
 331         if (priv_size != ptr->priv_size)
 332                 return -EINVAL;
 333
 334         intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
 335         intel_pt_parse_terms(&intel_pt_pmu->format, "noretcomp",
 336                              &noretcomp_bit);
 337         intel_pt_parse_terms(&intel_pt_pmu->format, "mtc", &mtc_bit);
 338         mtc_freq_bits = perf_pmu__format_bits(&intel_pt_pmu->format,
 339                                               "mtc_period");
 340         intel_pt_parse_terms(&intel_pt_pmu->format, "cyc", &cyc_bit);
 341
 342         intel_pt_tsc_ctc_ratio(&tsc_ctc_ratio_n, &tsc_ctc_ratio_d);
 343
 344         if (perf_pmu__scan_file(intel_pt_pmu, "max_nonturbo_ratio",
 345                                 "%lu", &max_non_turbo_ratio) != 1)
 346                 max_non_turbo_ratio = 0;
 347
 348         filter = intel_pt_find_filter(session->evlist, ptr->intel_pt_pmu);
 349         filter_str_len = filter ? strlen(filter) : 0;
 350
 351         if (!session->evlist->nr_mmaps)
 352                 return -EINVAL;
 353
 354         pc = session->evlist->mmap[0].base;
 355         if (pc) {
 356                 err = perf_read_tsc_conversion(pc, &tc);
 357                 if (err) {
 358                         if (err != -EOPNOTSUPP)
 359                                 return err;
 360                 } else {
 361                         cap_user_time_zero = tc.time_mult != 0;
 362                 }
 363                 if (!cap_user_time_zero)
 364                         ui__warning("Intel Processor Trace: TSC not available\n");
 365         }
 366
 367         per_cpu_mmaps = !cpu_map__empty(session->evlist->cpus);
 368
 369         auxtrace_info->type = PERF_AUXTRACE_INTEL_PT;
 370         auxtrace_info->priv[INTEL_PT_PMU_TYPE] = intel_pt_pmu->type;
 371         auxtrace_info->priv[INTEL_PT_TIME_SHIFT] = tc.time_shift;
 372         auxtrace_info->priv[INTEL_PT_TIME_MULT] = tc.time_mult;
 373         auxtrace_info->priv[INTEL_PT_TIME_ZERO] = tc.time_zero;
 374         auxtrace_info->priv[INTEL_PT_CAP_USER_TIME_ZERO] = cap_user_time_zero;
 375         auxtrace_info->priv[INTEL_PT_TSC_BIT] = tsc_bit;
 376         auxtrace_info->priv[INTEL_PT_NORETCOMP_BIT] = noretcomp_bit;
 377         auxtrace_info->priv[INTEL_PT_HAVE_SCHED_SWITCH] = ptr->have_sched_switch;
 378         auxtrace_info->priv[INTEL_PT_SNAPSHOT_MODE] = ptr->snapshot_mode;
 379         auxtrace_info->priv[INTEL_PT_PER_CPU_MMAPS] = per_cpu_mmaps;
 380         auxtrace_info->priv[INTEL_PT_MTC_BIT] = mtc_bit;
 381         auxtrace_info->priv[INTEL_PT_MTC_FREQ_BITS] = mtc_freq_bits;
 382         auxtrace_info->priv[INTEL_PT_TSC_CTC_N] = tsc_ctc_ratio_n;
 383         auxtrace_info->priv[INTEL_PT_TSC_CTC_D] = tsc_ctc_ratio_d;
 384         auxtrace_info->priv[INTEL_PT_CYC_BIT] = cyc_bit;
 385         auxtrace_info->priv[INTEL_PT_MAX_NONTURBO_RATIO] = max_non_turbo_ratio;
 386         auxtrace_info->priv[INTEL_PT_FILTER_STR_LEN] = filter_str_len;
 387
 388         info = &auxtrace_info->priv[INTEL_PT_FILTER_STR_LEN] + 1;
 389
 390         if (filter_str_len) {
 391                 size_t len = intel_pt_filter_bytes(filter);
 392
 393                 strncpy((char *)info, filter, len);
 394                 info += len >> 3;
 395         }
 396
 397         return 0;
 398 }
 399
 400 static int intel_pt_track_switches(struct perf_evlist *evlist)
 401 {
 402         const char *sched_switch = "sched:sched_switch";
 403         struct perf_evsel *evsel;
 404         int err;
 405
 406         if (!perf_evlist__can_select_event(evlist, sched_switch))
 407                 return -EPERM;
 408
 409         err = parse_events(evlist, sched_switch, NULL);
 410         if (err) {
 411                 pr_debug2("%s: failed to parse %s, error %d\n",
 412                           __func__, sched_switch, err);
 413                 return err;
 414         }
 415
 416         evsel = perf_evlist__last(evlist);
 417
 418         perf_evsel__set_sample_bit(evsel, CPU);
 419         perf_evsel__set_sample_bit(evsel, TIME);
 420
 421         evsel->system_wide = true;
 422         evsel->no_aux_samples = true;
 423         evsel->immediate = true;
 424
 425         return 0;
 426 }
 427
 428 static void intel_pt_valid_str(char *str, size_t len, u64 valid)
 429 {
 430         unsigned int val, last = 0, state = 1;
 431         int p = 0;
 432
 433         str[0] = '\0';
 434
 435         for (val = 0; val <= 64; val++, valid >>= 1) {
 436                 if (valid & 1) {
 437                         last = val;
 438                         switch (state) {
 439                         case 0:
 440                                 p += scnprintf(str + p, len - p, ",");
 441                                 /* Fall through */
 442                         case 1:
 443                                 p += scnprintf(str + p, len - p, "%u", val);
 444                                 state = 2;
 445                                 break;
 446                         case 2:
 447                                 state = 3;
 448                                 break;
 449                         case 3:
 450                                 state = 4;
 451                                 break;
 452                         default:
 453                                 break;
 454                         }
 455                 } else {
 456                         switch (state) {
 457                         case 3:
 458                                 p += scnprintf(str + p, len - p, ",%u", last);
 459                                 state = 0;
 460                                 break;
 461                         case 4:
 462                                 p += scnprintf(str + p, len - p, "-%u", last);
 463                                 state = 0;
 464                                 break;
 465                         default:
 466                                 break;
 467                         }
 468                         if (state != 1)
 469                                 state = 0;
 470                 }
 471         }
 472 }
 473
 474 static int intel_pt_val_config_term(struct perf_pmu *intel_pt_pmu,
 475                                     const char *caps, const char *name,
 476                                     const char *supported, u64 config)
 477 {
 478         char valid_str[256];
 479         unsigned int shift;
 480         unsigned long long valid;
 481         u64 bits;
 482         int ok;
 483
 484         if (perf_pmu__scan_file(intel_pt_pmu, caps, "%llx", &valid) != 1)
 485                 valid = 0;
 486
 487         if (supported &&
 488             perf_pmu__scan_file(intel_pt_pmu, supported, "%d", &ok) == 1 && !ok)
 489                 valid = 0;
 490
 491         valid |= 1;
 492
 493         bits = perf_pmu__format_bits(&intel_pt_pmu->format, name);
 494
 495         config &= bits;
 496
 497         for (shift = 0; bits && !(bits & 1); shift++)
 498                 bits >>= 1;
 499
 500         config >>= shift;
 501
 502         if (config > 63)
 503                 goto out_err;
 504
 505         if (valid & (1 << config))
 506                 return 0;
 507 out_err:
 508         intel_pt_valid_str(valid_str, sizeof(valid_str), valid);
 509         pr_err("Invalid %s for %s. Valid values are: %s\n",
 510                name, INTEL_PT_PMU_NAME, valid_str);
 511         return -EINVAL;
 512 }
 513
 514 static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu,
 515                                     struct perf_evsel *evsel)
 516 {
 517         int err;
 518         char c;
 519
 520         if (!evsel)
 521                 return 0;
 522
 523         /*
 524          * If supported, force pass-through config term (pt=1) even if user
 525          * sets pt=0, which avoids senseless kernel errors.
 526          */
 527         if (perf_pmu__scan_file(intel_pt_pmu, "format/pt", "%c", &c) == 1 &&
 528             !(evsel->attr.config & 1)) {
 529                 pr_warning("pt=0 doesn't make sense, forcing pt=1\n");
 530                 evsel->attr.config |= 1;
 531         }
 532
 533         err = intel_pt_val_config_term(intel_pt_pmu, "caps/cycle_thresholds",
 534                                        "cyc_thresh", "caps/psb_cyc",
 535                                        evsel->attr.config);
 536         if (err)
 537                 return err;
 538
 539         err = intel_pt_val_config_term(intel_pt_pmu, "caps/mtc_periods",
 540                                        "mtc_period", "caps/mtc",
 541                                        evsel->attr.config);
 542         if (err)
 543                 return err;
 544
 545         return intel_pt_val_config_term(intel_pt_pmu, "caps/psb_periods",
 546                                         "psb_period", "caps/psb_cyc",
 547                                         evsel->attr.config);
 548 }
 549
 550 static int intel_pt_recording_options(struct auxtrace_record *itr,
 551                                       struct perf_evlist *evlist,
 552                                       struct record_opts *opts)
 553 {
 554         struct intel_pt_recording *ptr =
 555                         container_of(itr, struct intel_pt_recording, itr);
 556         struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
 557         bool have_timing_info, need_immediate = false;
 558         struct perf_evsel *evsel, *intel_pt_evsel = NULL;
 559         const struct cpu_map *cpus = evlist->cpus;
 560         bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
 561         u64 tsc_bit;
 562         int err;
 563
 564         ptr->evlist = evlist;
 565         ptr->snapshot_mode = opts->auxtrace_snapshot_mode;
 566
 567         evlist__for_each_entry(evlist, evsel) {
 568                 if (evsel->attr.type == intel_pt_pmu->type) {
 569                         if (intel_pt_evsel) {
 570                                 pr_err("There may be only one " INTEL_PT_PMU_NAME " event\n");
 571                                 return -EINVAL;
 572                         }
 573                         evsel->attr.freq = 0;
 574                         evsel->attr.sample_period = 1;
 575                         intel_pt_evsel = evsel;
 576                         opts->full_auxtrace = true;
 577                 }
 578         }
 579
 580         if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
 581                 pr_err("Snapshot mode (-S option) requires " INTEL_PT_PMU_NAME " PMU event (-e " INTEL_PT_PMU_NAME ")\n");
 582                 return -EINVAL;
 583         }
 584
 585         if (opts->use_clockid) {
 586                 pr_err("Cannot use clockid (-k option) with " INTEL_PT_PMU_NAME "\n");
 587                 return -EINVAL;
 588         }
 589
 590         if (!opts->full_auxtrace)
 591                 return 0;
 592
 593         err = intel_pt_validate_config(intel_pt_pmu, intel_pt_evsel);
 594         if (err)
 595                 return err;
 596
 597         /* Set default sizes for snapshot mode */
 598         if (opts->auxtrace_snapshot_mode) {
 599                 size_t psb_period = intel_pt_psb_period(intel_pt_pmu, evlist);
 600
 601                 if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
 602                         if (privileged) {
 603                                 opts->auxtrace_mmap_pages = MiB(4) / page_size;
 604                         } else {
 605                                 opts->auxtrace_mmap_pages = KiB(128) / page_size;
 606                                 if (opts->mmap_pages == UINT_MAX)
 607                                         opts->mmap_pages = KiB(256) / page_size;
 608                         }
 609                 } else if (!opts->auxtrace_mmap_pages && !privileged &&
 610                            opts->mmap_pages == UINT_MAX) {
 611                         opts->mmap_pages = KiB(256) / page_size;
 612                 }
 613                 if (!opts->auxtrace_snapshot_size)
 614                         opts->auxtrace_snapshot_size =
 615                                 opts->auxtrace_mmap_pages * (size_t)page_size;
 616                 if (!opts->auxtrace_mmap_pages) {
 617                         size_t sz = opts->auxtrace_snapshot_size;
 618
 619                         sz = round_up(sz, page_size) / page_size;
 620                         opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
 621                 }
 622                 if (opts->auxtrace_snapshot_size >
 623                                 opts->auxtrace_mmap_pages * (size_t)page_size) {
 624                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
 625                                opts->auxtrace_snapshot_size,
 626                                opts->auxtrace_mmap_pages * (size_t)page_size);
 627                         return -EINVAL;
 628                 }
 629                 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
 630                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
 631                         return -EINVAL;
 632                 }
 633                 pr_debug2("Intel PT snapshot size: %zu\n",
 634                           opts->auxtrace_snapshot_size);
 635                 if (psb_period &&
 636                     opts->auxtrace_snapshot_size <= psb_period +
 637                                                   INTEL_PT_PSB_PERIOD_NEAR)
 638                         ui__warning("Intel PT snapshot size (%zu) may be too small for PSB period (%zu)\n",
 639                                     opts->auxtrace_snapshot_size, psb_period);
 640         }
 641
 642         /* Set default sizes for full trace mode */
 643         if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
 644                 if (privileged) {
 645                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 646                 } else {
 647                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 648                         if (opts->mmap_pages == UINT_MAX)
 649                                 opts->mmap_pages = KiB(256) / page_size;
 650                 }
 651         }
 652
 653         /* Validate auxtrace_mmap_pages */
 654         if (opts->auxtrace_mmap_pages) {
 655                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
 656                 size_t min_sz;
 657
 658                 if (opts->auxtrace_snapshot_mode)
 659                         min_sz = KiB(4);
 660                 else
 661                         min_sz = KiB(8);
 662
 663                 if (sz < min_sz || !is_power_of_2(sz)) {
 664                         pr_err("Invalid mmap size for Intel Processor Trace: must be at least %zuKiB and a power of 2\n",
 665                                min_sz / 1024);
 666                         return -EINVAL;
 667                 }
 668         }
 669
 670         intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
 671
 672         if (opts->full_auxtrace && (intel_pt_evsel->attr.config & tsc_bit))
 673                 have_timing_info = true;
 674         else
 675                 have_timing_info = false;
 676
 677         /*
 678          * Per-cpu recording needs sched_switch events to distinguish different
 679          * threads.
 680          */
 681         if (have_timing_info && !cpu_map__empty(cpus)) {
 682                 if (perf_can_record_switch_events()) {
 683                         bool cpu_wide = !target__none(&opts->target) &&
 684                                         !target__has_task(&opts->target);
 685
 686                         if (!cpu_wide && perf_can_record_cpu_wide()) {
 687                                 struct perf_evsel *switch_evsel;
 688
 689                                 err = parse_events(evlist, "dummy:u", NULL);
 690                                 if (err)
 691                                         return err;
 692
 693                                 switch_evsel = perf_evlist__last(evlist);
 694
 695                                 switch_evsel->attr.freq = 0;
 696                                 switch_evsel->attr.sample_period = 1;
 697                                 switch_evsel->attr.context_switch = 1;
 698
 699                                 switch_evsel->system_wide = true;
 700                                 switch_evsel->no_aux_samples = true;
 701                                 switch_evsel->immediate = true;
 702
 703                                 perf_evsel__set_sample_bit(switch_evsel, TID);
 704                                 perf_evsel__set_sample_bit(switch_evsel, TIME);
 705                                 perf_evsel__set_sample_bit(switch_evsel, CPU);
 706                                 perf_evsel__reset_sample_bit(switch_evsel, BRANCH_STACK);
 707
 708                                 opts->record_switch_events = false;
 709                                 ptr->have_sched_switch = 3;
 710                         } else {
 711                                 opts->record_switch_events = true;
 712                                 need_immediate = true;
 713                                 if (cpu_wide)
 714                                         ptr->have_sched_switch = 3;
 715                                 else
 716                                         ptr->have_sched_switch = 2;
 717                         }
 718                 } else {
 719                         err = intel_pt_track_switches(evlist);
 720                         if (err == -EPERM)
 721                                 pr_debug2("Unable to select sched:sched_switch\n");
 722                         else if (err)
 723                                 return err;
 724                         else
 725                                 ptr->have_sched_switch = 1;
 726                 }
 727         }
 728
 729         if (intel_pt_evsel) {
 730                 /*
 731                  * To obtain the auxtrace buffer file descriptor, the auxtrace
 732                  * event must come first.
 733                  */
 734                 perf_evlist__to_front(evlist, intel_pt_evsel);
 735                 /*
 736                  * In the case of per-cpu mmaps, we need the CPU on the
 737                  * AUX event.
 738                  */
 739                 if (!cpu_map__empty(cpus))
 740                         perf_evsel__set_sample_bit(intel_pt_evsel, CPU);
 741         }
 742
 743         /* Add dummy event to keep tracking */
 744         if (opts->full_auxtrace) {
 745                 struct perf_evsel *tracking_evsel;
 746
 747                 err = parse_events(evlist, "dummy:u", NULL);
 748                 if (err)
 749                         return err;
 750
 751                 tracking_evsel = perf_evlist__last(evlist);
 752
 753                 perf_evlist__set_tracking_event(evlist, tracking_evsel);
 754
 755                 tracking_evsel->attr.freq = 0;
 756                 tracking_evsel->attr.sample_period = 1;
 757
 758                 tracking_evsel->no_aux_samples = true;
 759                 if (need_immediate)
 760                         tracking_evsel->immediate = true;
 761
 762                 /* In per-cpu case, always need the time of mmap events etc */
 763                 if (!cpu_map__empty(cpus)) {
 764                         perf_evsel__set_sample_bit(tracking_evsel, TIME);
 765                         /* And the CPU for switch events */
 766                         perf_evsel__set_sample_bit(tracking_evsel, CPU);
 767                 }
 768                 perf_evsel__reset_sample_bit(tracking_evsel, BRANCH_STACK);
 769         }
 770
 771         /*
 772          * Warn the user when we do not have enough information to decode i.e.
 773          * per-cpu with no sched_switch (except workload-only).
 774          */
 775         if (!ptr->have_sched_switch && !cpu_map__empty(cpus) &&
 776             !target__none(&opts->target))
 777                 ui__warning("Intel Processor Trace decoding will not be possible except for kernel tracing!\n");
 778
 779         return 0;
 780 }
 781
 782 static int intel_pt_snapshot_start(struct auxtrace_record *itr)
 783 {
 784         struct intel_pt_recording *ptr =
 785                         container_of(itr, struct intel_pt_recording, itr);
 786         struct perf_evsel *evsel;
 787
 788         evlist__for_each_entry(ptr->evlist, evsel) {
 789                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
 790                         return perf_evsel__disable(evsel);
 791         }
 792         return -EINVAL;
 793 }
 794
 795 static int intel_pt_snapshot_finish(struct auxtrace_record *itr)
 796 {
 797         struct intel_pt_recording *ptr =
 798                         container_of(itr, struct intel_pt_recording, itr);
 799         struct perf_evsel *evsel;
 800
 801         evlist__for_each_entry(ptr->evlist, evsel) {
 802                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
 803                         return perf_evsel__enable(evsel);
 804         }
 805         return -EINVAL;
 806 }
 807
 808 static int intel_pt_alloc_snapshot_refs(struct intel_pt_recording *ptr, int idx)
 809 {
 810         const size_t sz = sizeof(struct intel_pt_snapshot_ref);
 811         int cnt = ptr->snapshot_ref_cnt, new_cnt = cnt * 2;
 812         struct intel_pt_snapshot_ref *refs;
 813
 814         if (!new_cnt)
 815                 new_cnt = 16;
 816
 817         while (new_cnt <= idx)
 818                 new_cnt *= 2;
 819
 820         refs = calloc(new_cnt, sz);
 821         if (!refs)
 822                 return -ENOMEM;
 823
 824         memcpy(refs, ptr->snapshot_refs, cnt * sz);
 825
 826         ptr->snapshot_refs = refs;
 827         ptr->snapshot_ref_cnt = new_cnt;
 828
 829         return 0;
 830 }
 831
 832 static void intel_pt_free_snapshot_refs(struct intel_pt_recording *ptr)
 833 {
 834         int i;
 835
 836         for (i = 0; i < ptr->snapshot_ref_cnt; i++)
 837                 zfree(&ptr->snapshot_refs[i].ref_buf);
 838         zfree(&ptr->snapshot_refs);
 839 }
 840
 841 static void intel_pt_recording_free(struct auxtrace_record *itr)
 842 {
 843         struct intel_pt_recording *ptr =
 844                         container_of(itr, struct intel_pt_recording, itr);
 845
 846         intel_pt_free_snapshot_refs(ptr);
 847         free(ptr);
 848 }
 849
 850 static int intel_pt_alloc_snapshot_ref(struct intel_pt_recording *ptr, int idx,
 851                                        size_t snapshot_buf_size)
 852 {
 853         size_t ref_buf_size = ptr->snapshot_ref_buf_size;
 854         void *ref_buf;
 855
 856         ref_buf = zalloc(ref_buf_size);
 857         if (!ref_buf)
 858                 return -ENOMEM;
 859
 860         ptr->snapshot_refs[idx].ref_buf = ref_buf;
 861         ptr->snapshot_refs[idx].ref_offset = snapshot_buf_size - ref_buf_size;
 862
 863         return 0;
 864 }
 865
 866 static size_t intel_pt_snapshot_ref_buf_size(struct intel_pt_recording *ptr,
 867                                              size_t snapshot_buf_size)
 868 {
 869         const size_t max_size = 256 * 1024;
 870         size_t buf_size = 0, psb_period;
 871
 872         if (ptr->snapshot_size <= 64 * 1024)
 873                 return 0;
 874
 875         psb_period = intel_pt_psb_period(ptr->intel_pt_pmu, ptr->evlist);
 876         if (psb_period)
 877                 buf_size = psb_period * 2;
 878
 879         if (!buf_size || buf_size > max_size)
 880                 buf_size = max_size;
 881
 882         if (buf_size >= snapshot_buf_size)
 883                 return 0;
 884
 885         if (buf_size >= ptr->snapshot_size / 2)
 886                 return 0;
 887
 888         return buf_size;
 889 }
 890
 891 static int intel_pt_snapshot_init(struct intel_pt_recording *ptr,
 892                                   size_t snapshot_buf_size)
 893 {
 894         if (ptr->snapshot_init_done)
 895                 return 0;
 896
 897         ptr->snapshot_init_done = true;
 898
 899         ptr->snapshot_ref_buf_size = intel_pt_snapshot_ref_buf_size(ptr,
 900                                                         snapshot_buf_size);
 901
 902         return 0;
 903 }
 904
 905 /**
 906  * intel_pt_compare_buffers - compare bytes in a buffer to a circular buffer.
 907  * @buf1: first buffer
 908  * @compare_size: number of bytes to compare
 909  * @buf2: second buffer (a circular buffer)
 910  * @offs2: offset in second buffer
 911  * @buf2_size: size of second buffer
 912  *
 913  * The comparison allows for the possibility that the bytes to compare in the
 914  * circular buffer are not contiguous.  It is assumed that @compare_size <=
 915  * @buf2_size.  This function returns %false if the bytes are identical, %true
 916  * otherwise.
 917  */
 918 static bool intel_pt_compare_buffers(void *buf1, size_t compare_size,
 919                                      void *buf2, size_t offs2, size_t buf2_size)
 920 {
 921         size_t end2 = offs2 + compare_size, part_size;
 922
 923         if (end2 <= buf2_size)
 924                 return memcmp(buf1, buf2 + offs2, compare_size);
 925
 926         part_size = end2 - buf2_size;
 927         if (memcmp(buf1, buf2 + offs2, part_size))
 928                 return true;
 929
 930         compare_size -= part_size;
 931
 932         return memcmp(buf1 + part_size, buf2, compare_size);
 933 }
 934
 935 static bool intel_pt_compare_ref(void *ref_buf, size_t ref_offset,
 936                                  size_t ref_size, size_t buf_size,
 937                                  void *data, size_t head)
 938 {
 939         size_t ref_end = ref_offset + ref_size;
 940
 941         if (ref_end > buf_size) {
 942                 if (head > ref_offset || head < ref_end - buf_size)
 943                         return true;
 944         } else if (head > ref_offset && head < ref_end) {
 945                 return true;
 946         }
 947
 948         return intel_pt_compare_buffers(ref_buf, ref_size, data, ref_offset,
 949                                         buf_size);
 950 }
 951
 952 static void intel_pt_copy_ref(void *ref_buf, size_t ref_size, size_t buf_size,
 953                               void *data, size_t head)
 954 {
 955         if (head >= ref_size) {
 956                 memcpy(ref_buf, data + head - ref_size, ref_size);
 957         } else {
 958                 memcpy(ref_buf, data, head);
 959                 ref_size -= head;
 960                 memcpy(ref_buf + head, data + buf_size - ref_size, ref_size);
 961         }
 962 }
 963
 964 static bool intel_pt_wrapped(struct intel_pt_recording *ptr, int idx,
 965                              struct auxtrace_mmap *mm, unsigned char *data,
 966                              u64 head)
 967 {
 968         struct intel_pt_snapshot_ref *ref = &ptr->snapshot_refs[idx];
 969         bool wrapped;
 970
 971         wrapped = intel_pt_compare_ref(ref->ref_buf, ref->ref_offset,
 972                                        ptr->snapshot_ref_buf_size, mm->len,
 973                                        data, head);
 974
 975         intel_pt_copy_ref(ref->ref_buf, ptr->snapshot_ref_buf_size, mm->len,
 976                           data, head);
 977
 978         return wrapped;
 979 }
 980
 981 static bool intel_pt_first_wrap(u64 *data, size_t buf_size)
 982 {
 983         int i, a, b;
 984
 985         b = buf_size >> 3;
 986         a = b - 512;
 987         if (a < 0)
 988                 a = 0;
 989
 990         for (i = a; i < b; i++) {
 991                 if (data[i])
 992                         return true;
 993         }
 994
 995         return false;
 996 }
 997
 998 static int intel_pt_find_snapshot(struct auxtrace_record *itr, int idx,
 999                                   struct auxtrace_mmap *mm, unsigned char *data,
1000                                   u64 *head, u64 *old)
1001 {
1002         struct intel_pt_recording *ptr =
1003                         container_of(itr, struct intel_pt_recording, itr);
1004         bool wrapped;
1005         int err;
1006
1007         pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
1008                   __func__, idx, (size_t)*old, (size_t)*head);
1009
1010         err = intel_pt_snapshot_init(ptr, mm->len);
1011         if (err)
1012                 goto out_err;
1013
1014         if (idx >= ptr->snapshot_ref_cnt) {
1015                 err = intel_pt_alloc_snapshot_refs(ptr, idx);
1016                 if (err)
1017                         goto out_err;
1018         }
1019
1020         if (ptr->snapshot_ref_buf_size) {
1021                 if (!ptr->snapshot_refs[idx].ref_buf) {
1022                         err = intel_pt_alloc_snapshot_ref(ptr, idx, mm->len);
1023                         if (err)
1024                                 goto out_err;
1025                 }
1026                 wrapped = intel_pt_wrapped(ptr, idx, mm, data, *head);
1027         } else {
1028                 wrapped = ptr->snapshot_refs[idx].wrapped;
1029                 if (!wrapped && intel_pt_first_wrap((u64 *)data, mm->len)) {
1030                         ptr->snapshot_refs[idx].wrapped = true;
1031                         wrapped = true;
1032                 }
1033         }
1034
1035         /*
1036          * In full trace mode 'head' continually increases.  However in snapshot
1037          * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
1038          * are adjusted to match the full trace case which expects that 'old' is
1039          * always less than 'head'.
1040          */
1041         if (wrapped) {
1042                 *old = *head;
1043                 *head += mm->len;
1044         } else {
1045                 if (mm->mask)
1046                         *old &= mm->mask;
1047                 else
1048                         *old %= mm->len;
1049                 if (*old > *head)
1050                         *head += mm->len;
1051         }
1052
1053         pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
1054                   __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
1055
1056         return 0;
1057
1058 out_err:
1059         pr_err("%s: failed, error %d\n", __func__, err);
1060         return err;
1061 }
1062
1063 static u64 intel_pt_reference(struct auxtrace_record *itr __maybe_unused)
1064 {
1065         return rdtsc();
1066 }
1067
1068 static int intel_pt_read_finish(struct auxtrace_record *itr, int idx)
1069 {
1070         struct intel_pt_recording *ptr =
1071                         container_of(itr, struct intel_pt_recording, itr);
1072         struct perf_evsel *evsel;
1073
1074         evlist__for_each_entry(ptr->evlist, evsel) {
1075                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
1076                         return perf_evlist__enable_event_idx(ptr->evlist, evsel,
1077                                                              idx);
1078         }
1079         return -EINVAL;
1080 }
1081
1082 struct auxtrace_record *intel_pt_recording_init(int *err)
1083 {
1084         struct perf_pmu *intel_pt_pmu = perf_pmu__find(INTEL_PT_PMU_NAME);
1085         struct intel_pt_recording *ptr;
1086
1087         if (!intel_pt_pmu)
1088                 return NULL;
1089
1090         if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
1091                 *err = -errno;
1092                 return NULL;
1093         }
1094
1095         ptr = zalloc(sizeof(struct intel_pt_recording));
1096         if (!ptr) {
1097                 *err = -ENOMEM;
1098                 return NULL;
1099         }
1100
1101         ptr->intel_pt_pmu = intel_pt_pmu;
1102         ptr->itr.recording_options = intel_pt_recording_options;
1103         ptr->itr.info_priv_size = intel_pt_info_priv_size;
1104         ptr->itr.info_fill = intel_pt_info_fill;
1105         ptr->itr.free = intel_pt_recording_free;
1106         ptr->itr.snapshot_start = intel_pt_snapshot_start;
1107         ptr->itr.snapshot_finish = intel_pt_snapshot_finish;
1108         ptr->itr.find_snapshot = intel_pt_find_snapshot;
1109         ptr->itr.parse_snapshot_options = intel_pt_parse_snapshot_options;
1110         ptr->itr.reference = intel_pt_reference;
1111         ptr->itr.read_finish = intel_pt_read_finish;
1112         return &ptr->itr;
1113 }