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

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