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 "../../util/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__free_terms(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(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 intel_pt_info_priv_size(struct auxtrace_record *itr __maybe_unused)
 277 {
 278         return INTEL_PT_AUXTRACE_PRIV_SIZE;
 279 }
 280
 281 static void intel_pt_tsc_ctc_ratio(u32 *n, u32 *d)
 282 {
 283         unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0;
 284
 285         __get_cpuid(0x15, &eax, &ebx, &ecx, &edx);
 286         *n = ebx;
 287         *d = eax;
 288 }
 289
 290 static int intel_pt_info_fill(struct auxtrace_record *itr,
 291                               struct perf_session *session,
 292                               struct auxtrace_info_event *auxtrace_info,
 293                               size_t priv_size)
 294 {
 295         struct intel_pt_recording *ptr =
 296                         container_of(itr, struct intel_pt_recording, itr);
 297         struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
 298         struct perf_event_mmap_page *pc;
 299         struct perf_tsc_conversion tc = { .time_mult = 0, };
 300         bool cap_user_time_zero = false, per_cpu_mmaps;
 301         u64 tsc_bit, mtc_bit, mtc_freq_bits, cyc_bit, noretcomp_bit;
 302         u32 tsc_ctc_ratio_n, tsc_ctc_ratio_d;
 303         int err;
 304
 305         if (priv_size != INTEL_PT_AUXTRACE_PRIV_SIZE)
 306                 return -EINVAL;
 307
 308         intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
 309         intel_pt_parse_terms(&intel_pt_pmu->format, "noretcomp",
 310                              &noretcomp_bit);
 311         intel_pt_parse_terms(&intel_pt_pmu->format, "mtc", &mtc_bit);
 312         mtc_freq_bits = perf_pmu__format_bits(&intel_pt_pmu->format,
 313                                               "mtc_period");
 314         intel_pt_parse_terms(&intel_pt_pmu->format, "cyc", &cyc_bit);
 315
 316         intel_pt_tsc_ctc_ratio(&tsc_ctc_ratio_n, &tsc_ctc_ratio_d);
 317
 318         if (!session->evlist->nr_mmaps)
 319                 return -EINVAL;
 320
 321         pc = session->evlist->mmap[0].base;
 322         if (pc) {
 323                 err = perf_read_tsc_conversion(pc, &tc);
 324                 if (err) {
 325                         if (err != -EOPNOTSUPP)
 326                                 return err;
 327                 } else {
 328                         cap_user_time_zero = tc.time_mult != 0;
 329                 }
 330                 if (!cap_user_time_zero)
 331                         ui__warning("Intel Processor Trace: TSC not available\n");
 332         }
 333
 334         per_cpu_mmaps = !cpu_map__empty(session->evlist->cpus);
 335
 336         auxtrace_info->type = PERF_AUXTRACE_INTEL_PT;
 337         auxtrace_info->priv[INTEL_PT_PMU_TYPE] = intel_pt_pmu->type;
 338         auxtrace_info->priv[INTEL_PT_TIME_SHIFT] = tc.time_shift;
 339         auxtrace_info->priv[INTEL_PT_TIME_MULT] = tc.time_mult;
 340         auxtrace_info->priv[INTEL_PT_TIME_ZERO] = tc.time_zero;
 341         auxtrace_info->priv[INTEL_PT_CAP_USER_TIME_ZERO] = cap_user_time_zero;
 342         auxtrace_info->priv[INTEL_PT_TSC_BIT] = tsc_bit;
 343         auxtrace_info->priv[INTEL_PT_NORETCOMP_BIT] = noretcomp_bit;
 344         auxtrace_info->priv[INTEL_PT_HAVE_SCHED_SWITCH] = ptr->have_sched_switch;
 345         auxtrace_info->priv[INTEL_PT_SNAPSHOT_MODE] = ptr->snapshot_mode;
 346         auxtrace_info->priv[INTEL_PT_PER_CPU_MMAPS] = per_cpu_mmaps;
 347         auxtrace_info->priv[INTEL_PT_MTC_BIT] = mtc_bit;
 348         auxtrace_info->priv[INTEL_PT_MTC_FREQ_BITS] = mtc_freq_bits;
 349         auxtrace_info->priv[INTEL_PT_TSC_CTC_N] = tsc_ctc_ratio_n;
 350         auxtrace_info->priv[INTEL_PT_TSC_CTC_D] = tsc_ctc_ratio_d;
 351         auxtrace_info->priv[INTEL_PT_CYC_BIT] = cyc_bit;
 352
 353         return 0;
 354 }
 355
 356 static int intel_pt_track_switches(struct perf_evlist *evlist)
 357 {
 358         const char *sched_switch = "sched:sched_switch";
 359         struct perf_evsel *evsel;
 360         int err;
 361
 362         if (!perf_evlist__can_select_event(evlist, sched_switch))
 363                 return -EPERM;
 364
 365         err = parse_events(evlist, sched_switch, NULL);
 366         if (err) {
 367                 pr_debug2("%s: failed to parse %s, error %d\n",
 368                           __func__, sched_switch, err);
 369                 return err;
 370         }
 371
 372         evsel = perf_evlist__last(evlist);
 373
 374         perf_evsel__set_sample_bit(evsel, CPU);
 375         perf_evsel__set_sample_bit(evsel, TIME);
 376
 377         evsel->system_wide = true;
 378         evsel->no_aux_samples = true;
 379         evsel->immediate = true;
 380
 381         return 0;
 382 }
 383
 384 static void intel_pt_valid_str(char *str, size_t len, u64 valid)
 385 {
 386         unsigned int val, last = 0, state = 1;
 387         int p = 0;
 388
 389         str[0] = '\0';
 390
 391         for (val = 0; val <= 64; val++, valid >>= 1) {
 392                 if (valid & 1) {
 393                         last = val;
 394                         switch (state) {
 395                         case 0:
 396                                 p += scnprintf(str + p, len - p, ",");
 397                                 /* Fall through */
 398                         case 1:
 399                                 p += scnprintf(str + p, len - p, "%u", val);
 400                                 state = 2;
 401                                 break;
 402                         case 2:
 403                                 state = 3;
 404                                 break;
 405                         case 3:
 406                                 state = 4;
 407                                 break;
 408                         default:
 409                                 break;
 410                         }
 411                 } else {
 412                         switch (state) {
 413                         case 3:
 414                                 p += scnprintf(str + p, len - p, ",%u", last);
 415                                 state = 0;
 416                                 break;
 417                         case 4:
 418                                 p += scnprintf(str + p, len - p, "-%u", last);
 419                                 state = 0;
 420                                 break;
 421                         default:
 422                                 break;
 423                         }
 424                         if (state != 1)
 425                                 state = 0;
 426                 }
 427         }
 428 }
 429
 430 static int intel_pt_val_config_term(struct perf_pmu *intel_pt_pmu,
 431                                     const char *caps, const char *name,
 432                                     const char *supported, u64 config)
 433 {
 434         char valid_str[256];
 435         unsigned int shift;
 436         unsigned long long valid;
 437         u64 bits;
 438         int ok;
 439
 440         if (perf_pmu__scan_file(intel_pt_pmu, caps, "%llx", &valid) != 1)
 441                 valid = 0;
 442
 443         if (supported &&
 444             perf_pmu__scan_file(intel_pt_pmu, supported, "%d", &ok) == 1 && !ok)
 445                 valid = 0;
 446
 447         valid |= 1;
 448
 449         bits = perf_pmu__format_bits(&intel_pt_pmu->format, name);
 450
 451         config &= bits;
 452
 453         for (shift = 0; bits && !(bits & 1); shift++)
 454                 bits >>= 1;
 455
 456         config >>= shift;
 457
 458         if (config > 63)
 459                 goto out_err;
 460
 461         if (valid & (1 << config))
 462                 return 0;
 463 out_err:
 464         intel_pt_valid_str(valid_str, sizeof(valid_str), valid);
 465         pr_err("Invalid %s for %s. Valid values are: %s\n",
 466                name, INTEL_PT_PMU_NAME, valid_str);
 467         return -EINVAL;
 468 }
 469
 470 static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu,
 471                                     struct perf_evsel *evsel)
 472 {
 473         int err;
 474
 475         if (!evsel)
 476                 return 0;
 477
 478         err = intel_pt_val_config_term(intel_pt_pmu, "caps/cycle_thresholds",
 479                                        "cyc_thresh", "caps/psb_cyc",
 480                                        evsel->attr.config);
 481         if (err)
 482                 return err;
 483
 484         err = intel_pt_val_config_term(intel_pt_pmu, "caps/mtc_periods",
 485                                        "mtc_period", "caps/mtc",
 486                                        evsel->attr.config);
 487         if (err)
 488                 return err;
 489
 490         return intel_pt_val_config_term(intel_pt_pmu, "caps/psb_periods",
 491                                         "psb_period", "caps/psb_cyc",
 492                                         evsel->attr.config);
 493 }
 494
 495 static int intel_pt_recording_options(struct auxtrace_record *itr,
 496                                       struct perf_evlist *evlist,
 497                                       struct record_opts *opts)
 498 {
 499         struct intel_pt_recording *ptr =
 500                         container_of(itr, struct intel_pt_recording, itr);
 501         struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
 502         bool have_timing_info;
 503         struct perf_evsel *evsel, *intel_pt_evsel = NULL;
 504         const struct cpu_map *cpus = evlist->cpus;
 505         bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
 506         u64 tsc_bit;
 507         int err;
 508
 509         ptr->evlist = evlist;
 510         ptr->snapshot_mode = opts->auxtrace_snapshot_mode;
 511
 512         evlist__for_each(evlist, evsel) {
 513                 if (evsel->attr.type == intel_pt_pmu->type) {
 514                         if (intel_pt_evsel) {
 515                                 pr_err("There may be only one " INTEL_PT_PMU_NAME " event\n");
 516                                 return -EINVAL;
 517                         }
 518                         evsel->attr.freq = 0;
 519                         evsel->attr.sample_period = 1;
 520                         intel_pt_evsel = evsel;
 521                         opts->full_auxtrace = true;
 522                 }
 523         }
 524
 525         if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
 526                 pr_err("Snapshot mode (-S option) requires " INTEL_PT_PMU_NAME " PMU event (-e " INTEL_PT_PMU_NAME ")\n");
 527                 return -EINVAL;
 528         }
 529
 530         if (opts->use_clockid) {
 531                 pr_err("Cannot use clockid (-k option) with " INTEL_PT_PMU_NAME "\n");
 532                 return -EINVAL;
 533         }
 534
 535         if (!opts->full_auxtrace)
 536                 return 0;
 537
 538         err = intel_pt_validate_config(intel_pt_pmu, intel_pt_evsel);
 539         if (err)
 540                 return err;
 541
 542         /* Set default sizes for snapshot mode */
 543         if (opts->auxtrace_snapshot_mode) {
 544                 size_t psb_period = intel_pt_psb_period(intel_pt_pmu, evlist);
 545
 546                 if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
 547                         if (privileged) {
 548                                 opts->auxtrace_mmap_pages = MiB(4) / page_size;
 549                         } else {
 550                                 opts->auxtrace_mmap_pages = KiB(128) / page_size;
 551                                 if (opts->mmap_pages == UINT_MAX)
 552                                         opts->mmap_pages = KiB(256) / page_size;
 553                         }
 554                 } else if (!opts->auxtrace_mmap_pages && !privileged &&
 555                            opts->mmap_pages == UINT_MAX) {
 556                         opts->mmap_pages = KiB(256) / page_size;
 557                 }
 558                 if (!opts->auxtrace_snapshot_size)
 559                         opts->auxtrace_snapshot_size =
 560                                 opts->auxtrace_mmap_pages * (size_t)page_size;
 561                 if (!opts->auxtrace_mmap_pages) {
 562                         size_t sz = opts->auxtrace_snapshot_size;
 563
 564                         sz = round_up(sz, page_size) / page_size;
 565                         opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
 566                 }
 567                 if (opts->auxtrace_snapshot_size >
 568                                 opts->auxtrace_mmap_pages * (size_t)page_size) {
 569                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
 570                                opts->auxtrace_snapshot_size,
 571                                opts->auxtrace_mmap_pages * (size_t)page_size);
 572                         return -EINVAL;
 573                 }
 574                 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
 575                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
 576                         return -EINVAL;
 577                 }
 578                 pr_debug2("Intel PT snapshot size: %zu\n",
 579                           opts->auxtrace_snapshot_size);
 580                 if (psb_period &&
 581                     opts->auxtrace_snapshot_size <= psb_period +
 582                                                   INTEL_PT_PSB_PERIOD_NEAR)
 583                         ui__warning("Intel PT snapshot size (%zu) may be too small for PSB period (%zu)\n",
 584                                     opts->auxtrace_snapshot_size, psb_period);
 585         }
 586
 587         /* Set default sizes for full trace mode */
 588         if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
 589                 if (privileged) {
 590                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 591                 } else {
 592                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 593                         if (opts->mmap_pages == UINT_MAX)
 594                                 opts->mmap_pages = KiB(256) / page_size;
 595                 }
 596         }
 597
 598         /* Validate auxtrace_mmap_pages */
 599         if (opts->auxtrace_mmap_pages) {
 600                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
 601                 size_t min_sz;
 602
 603                 if (opts->auxtrace_snapshot_mode)
 604                         min_sz = KiB(4);
 605                 else
 606                         min_sz = KiB(8);
 607
 608                 if (sz < min_sz || !is_power_of_2(sz)) {
 609                         pr_err("Invalid mmap size for Intel Processor Trace: must be at least %zuKiB and a power of 2\n",
 610                                min_sz / 1024);
 611                         return -EINVAL;
 612                 }
 613         }
 614
 615         intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
 616
 617         if (opts->full_auxtrace && (intel_pt_evsel->attr.config & tsc_bit))
 618                 have_timing_info = true;
 619         else
 620                 have_timing_info = false;
 621
 622         /*
 623          * Per-cpu recording needs sched_switch events to distinguish different
 624          * threads.
 625          */
 626         if (have_timing_info && !cpu_map__empty(cpus)) {
 627                 if (perf_can_record_switch_events()) {
 628                         bool cpu_wide = !target__none(&opts->target) &&
 629                                         !target__has_task(&opts->target);
 630
 631                         if (!cpu_wide && perf_can_record_cpu_wide()) {
 632                                 struct perf_evsel *switch_evsel;
 633
 634                                 err = parse_events(evlist, "dummy:u", NULL);
 635                                 if (err)
 636                                         return err;
 637
 638                                 switch_evsel = perf_evlist__last(evlist);
 639
 640                                 switch_evsel->attr.freq = 0;
 641                                 switch_evsel->attr.sample_period = 1;
 642                                 switch_evsel->attr.context_switch = 1;
 643
 644                                 switch_evsel->system_wide = true;
 645                                 switch_evsel->no_aux_samples = true;
 646                                 switch_evsel->immediate = true;
 647
 648                                 perf_evsel__set_sample_bit(switch_evsel, TID);
 649                                 perf_evsel__set_sample_bit(switch_evsel, TIME);
 650                                 perf_evsel__set_sample_bit(switch_evsel, CPU);
 651
 652                                 opts->record_switch_events = false;
 653                                 ptr->have_sched_switch = 3;
 654                         } else {
 655                                 opts->record_switch_events = true;
 656                                 if (cpu_wide)
 657                                         ptr->have_sched_switch = 3;
 658                                 else
 659                                         ptr->have_sched_switch = 2;
 660                         }
 661                 } else {
 662                         err = intel_pt_track_switches(evlist);
 663                         if (err == -EPERM)
 664                                 pr_debug2("Unable to select sched:sched_switch\n");
 665                         else if (err)
 666                                 return err;
 667                         else
 668                                 ptr->have_sched_switch = 1;
 669                 }
 670         }
 671
 672         if (intel_pt_evsel) {
 673                 /*
 674                  * To obtain the auxtrace buffer file descriptor, the auxtrace
 675                  * event must come first.
 676                  */
 677                 perf_evlist__to_front(evlist, intel_pt_evsel);
 678                 /*
 679                  * In the case of per-cpu mmaps, we need the CPU on the
 680                  * AUX event.
 681                  */
 682                 if (!cpu_map__empty(cpus))
 683                         perf_evsel__set_sample_bit(intel_pt_evsel, CPU);
 684         }
 685
 686         /* Add dummy event to keep tracking */
 687         if (opts->full_auxtrace) {
 688                 struct perf_evsel *tracking_evsel;
 689
 690                 err = parse_events(evlist, "dummy:u", NULL);
 691                 if (err)
 692                         return err;
 693
 694                 tracking_evsel = perf_evlist__last(evlist);
 695
 696                 perf_evlist__set_tracking_event(evlist, tracking_evsel);
 697
 698                 tracking_evsel->attr.freq = 0;
 699                 tracking_evsel->attr.sample_period = 1;
 700
 701                 /* In per-cpu case, always need the time of mmap events etc */
 702                 if (!cpu_map__empty(cpus)) {
 703                         perf_evsel__set_sample_bit(tracking_evsel, TIME);
 704                         /* And the CPU for switch events */
 705                         perf_evsel__set_sample_bit(tracking_evsel, CPU);
 706                 }
 707         }
 708
 709         /*
 710          * Warn the user when we do not have enough information to decode i.e.
 711          * per-cpu with no sched_switch (except workload-only).
 712          */
 713         if (!ptr->have_sched_switch && !cpu_map__empty(cpus) &&
 714             !target__none(&opts->target))
 715                 ui__warning("Intel Processor Trace decoding will not be possible except for kernel tracing!\n");
 716
 717         return 0;
 718 }
 719
 720 static int intel_pt_snapshot_start(struct auxtrace_record *itr)
 721 {
 722         struct intel_pt_recording *ptr =
 723                         container_of(itr, struct intel_pt_recording, itr);
 724         struct perf_evsel *evsel;
 725
 726         evlist__for_each(ptr->evlist, evsel) {
 727                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
 728                         return perf_evlist__disable_event(ptr->evlist, evsel);
 729         }
 730         return -EINVAL;
 731 }
 732
 733 static int intel_pt_snapshot_finish(struct auxtrace_record *itr)
 734 {
 735         struct intel_pt_recording *ptr =
 736                         container_of(itr, struct intel_pt_recording, itr);
 737         struct perf_evsel *evsel;
 738
 739         evlist__for_each(ptr->evlist, evsel) {
 740                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
 741                         return perf_evlist__enable_event(ptr->evlist, evsel);
 742         }
 743         return -EINVAL;
 744 }
 745
 746 static int intel_pt_alloc_snapshot_refs(struct intel_pt_recording *ptr, int idx)
 747 {
 748         const size_t sz = sizeof(struct intel_pt_snapshot_ref);
 749         int cnt = ptr->snapshot_ref_cnt, new_cnt = cnt * 2;
 750         struct intel_pt_snapshot_ref *refs;
 751
 752         if (!new_cnt)
 753                 new_cnt = 16;
 754
 755         while (new_cnt <= idx)
 756                 new_cnt *= 2;
 757
 758         refs = calloc(new_cnt, sz);
 759         if (!refs)
 760                 return -ENOMEM;
 761
 762         memcpy(refs, ptr->snapshot_refs, cnt * sz);
 763
 764         ptr->snapshot_refs = refs;
 765         ptr->snapshot_ref_cnt = new_cnt;
 766
 767         return 0;
 768 }
 769
 770 static void intel_pt_free_snapshot_refs(struct intel_pt_recording *ptr)
 771 {
 772         int i;
 773
 774         for (i = 0; i < ptr->snapshot_ref_cnt; i++)
 775                 zfree(&ptr->snapshot_refs[i].ref_buf);
 776         zfree(&ptr->snapshot_refs);
 777 }
 778
 779 static void intel_pt_recording_free(struct auxtrace_record *itr)
 780 {
 781         struct intel_pt_recording *ptr =
 782                         container_of(itr, struct intel_pt_recording, itr);
 783
 784         intel_pt_free_snapshot_refs(ptr);
 785         free(ptr);
 786 }
 787
 788 static int intel_pt_alloc_snapshot_ref(struct intel_pt_recording *ptr, int idx,
 789                                        size_t snapshot_buf_size)
 790 {
 791         size_t ref_buf_size = ptr->snapshot_ref_buf_size;
 792         void *ref_buf;
 793
 794         ref_buf = zalloc(ref_buf_size);
 795         if (!ref_buf)
 796                 return -ENOMEM;
 797
 798         ptr->snapshot_refs[idx].ref_buf = ref_buf;
 799         ptr->snapshot_refs[idx].ref_offset = snapshot_buf_size - ref_buf_size;
 800
 801         return 0;
 802 }
 803
 804 static size_t intel_pt_snapshot_ref_buf_size(struct intel_pt_recording *ptr,
 805                                              size_t snapshot_buf_size)
 806 {
 807         const size_t max_size = 256 * 1024;
 808         size_t buf_size = 0, psb_period;
 809
 810         if (ptr->snapshot_size <= 64 * 1024)
 811                 return 0;
 812
 813         psb_period = intel_pt_psb_period(ptr->intel_pt_pmu, ptr->evlist);
 814         if (psb_period)
 815                 buf_size = psb_period * 2;
 816
 817         if (!buf_size || buf_size > max_size)
 818                 buf_size = max_size;
 819
 820         if (buf_size >= snapshot_buf_size)
 821                 return 0;
 822
 823         if (buf_size >= ptr->snapshot_size / 2)
 824                 return 0;
 825
 826         return buf_size;
 827 }
 828
 829 static int intel_pt_snapshot_init(struct intel_pt_recording *ptr,
 830                                   size_t snapshot_buf_size)
 831 {
 832         if (ptr->snapshot_init_done)
 833                 return 0;
 834
 835         ptr->snapshot_init_done = true;
 836
 837         ptr->snapshot_ref_buf_size = intel_pt_snapshot_ref_buf_size(ptr,
 838                                                         snapshot_buf_size);
 839
 840         return 0;
 841 }
 842
 843 /**
 844  * intel_pt_compare_buffers - compare bytes in a buffer to a circular buffer.
 845  * @buf1: first buffer
 846  * @compare_size: number of bytes to compare
 847  * @buf2: second buffer (a circular buffer)
 848  * @offs2: offset in second buffer
 849  * @buf2_size: size of second buffer
 850  *
 851  * The comparison allows for the possibility that the bytes to compare in the
 852  * circular buffer are not contiguous.  It is assumed that @compare_size <=
 853  * @buf2_size.  This function returns %false if the bytes are identical, %true
 854  * otherwise.
 855  */
 856 static bool intel_pt_compare_buffers(void *buf1, size_t compare_size,
 857                                      void *buf2, size_t offs2, size_t buf2_size)
 858 {
 859         size_t end2 = offs2 + compare_size, part_size;
 860
 861         if (end2 <= buf2_size)
 862                 return memcmp(buf1, buf2 + offs2, compare_size);
 863
 864         part_size = end2 - buf2_size;
 865         if (memcmp(buf1, buf2 + offs2, part_size))
 866                 return true;
 867
 868         compare_size -= part_size;
 869
 870         return memcmp(buf1 + part_size, buf2, compare_size);
 871 }
 872
 873 static bool intel_pt_compare_ref(void *ref_buf, size_t ref_offset,
 874                                  size_t ref_size, size_t buf_size,
 875                                  void *data, size_t head)
 876 {
 877         size_t ref_end = ref_offset + ref_size;
 878
 879         if (ref_end > buf_size) {
 880                 if (head > ref_offset || head < ref_end - buf_size)
 881                         return true;
 882         } else if (head > ref_offset && head < ref_end) {
 883                 return true;
 884         }
 885
 886         return intel_pt_compare_buffers(ref_buf, ref_size, data, ref_offset,
 887                                         buf_size);
 888 }
 889
 890 static void intel_pt_copy_ref(void *ref_buf, size_t ref_size, size_t buf_size,
 891                               void *data, size_t head)
 892 {
 893         if (head >= ref_size) {
 894                 memcpy(ref_buf, data + head - ref_size, ref_size);
 895         } else {
 896                 memcpy(ref_buf, data, head);
 897                 ref_size -= head;
 898                 memcpy(ref_buf + head, data + buf_size - ref_size, ref_size);
 899         }
 900 }
 901
 902 static bool intel_pt_wrapped(struct intel_pt_recording *ptr, int idx,
 903                              struct auxtrace_mmap *mm, unsigned char *data,
 904                              u64 head)
 905 {
 906         struct intel_pt_snapshot_ref *ref = &ptr->snapshot_refs[idx];
 907         bool wrapped;
 908
 909         wrapped = intel_pt_compare_ref(ref->ref_buf, ref->ref_offset,
 910                                        ptr->snapshot_ref_buf_size, mm->len,
 911                                        data, head);
 912
 913         intel_pt_copy_ref(ref->ref_buf, ptr->snapshot_ref_buf_size, mm->len,
 914                           data, head);
 915
 916         return wrapped;
 917 }
 918
 919 static bool intel_pt_first_wrap(u64 *data, size_t buf_size)
 920 {
 921         int i, a, b;
 922
 923         b = buf_size >> 3;
 924         a = b - 512;
 925         if (a < 0)
 926                 a = 0;
 927
 928         for (i = a; i < b; i++) {
 929                 if (data[i])
 930                         return true;
 931         }
 932
 933         return false;
 934 }
 935
 936 static int intel_pt_find_snapshot(struct auxtrace_record *itr, int idx,
 937                                   struct auxtrace_mmap *mm, unsigned char *data,
 938                                   u64 *head, u64 *old)
 939 {
 940         struct intel_pt_recording *ptr =
 941                         container_of(itr, struct intel_pt_recording, itr);
 942         bool wrapped;
 943         int err;
 944
 945         pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
 946                   __func__, idx, (size_t)*old, (size_t)*head);
 947
 948         err = intel_pt_snapshot_init(ptr, mm->len);
 949         if (err)
 950                 goto out_err;
 951
 952         if (idx >= ptr->snapshot_ref_cnt) {
 953                 err = intel_pt_alloc_snapshot_refs(ptr, idx);
 954                 if (err)
 955                         goto out_err;
 956         }
 957
 958         if (ptr->snapshot_ref_buf_size) {
 959                 if (!ptr->snapshot_refs[idx].ref_buf) {
 960                         err = intel_pt_alloc_snapshot_ref(ptr, idx, mm->len);
 961                         if (err)
 962                                 goto out_err;
 963                 }
 964                 wrapped = intel_pt_wrapped(ptr, idx, mm, data, *head);
 965         } else {
 966                 wrapped = ptr->snapshot_refs[idx].wrapped;
 967                 if (!wrapped && intel_pt_first_wrap((u64 *)data, mm->len)) {
 968                         ptr->snapshot_refs[idx].wrapped = true;
 969                         wrapped = true;
 970                 }
 971         }
 972
 973         /*
 974          * In full trace mode 'head' continually increases.  However in snapshot
 975          * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
 976          * are adjusted to match the full trace case which expects that 'old' is
 977          * always less than 'head'.
 978          */
 979         if (wrapped) {
 980                 *old = *head;
 981                 *head += mm->len;
 982         } else {
 983                 if (mm->mask)
 984                         *old &= mm->mask;
 985                 else
 986                         *old %= mm->len;
 987                 if (*old > *head)
 988                         *head += mm->len;
 989         }
 990
 991         pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
 992                   __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
 993
 994         return 0;
 995
 996 out_err:
 997         pr_err("%s: failed, error %d\n", __func__, err);
 998         return err;
 999 }
1000
1001 static u64 intel_pt_reference(struct auxtrace_record *itr __maybe_unused)
1002 {
1003         return rdtsc();
1004 }
1005
1006 static int intel_pt_read_finish(struct auxtrace_record *itr, int idx)
1007 {
1008         struct intel_pt_recording *ptr =
1009                         container_of(itr, struct intel_pt_recording, itr);
1010         struct perf_evsel *evsel;
1011
1012         evlist__for_each(ptr->evlist, evsel) {
1013                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
1014                         return perf_evlist__enable_event_idx(ptr->evlist, evsel,
1015                                                              idx);
1016         }
1017         return -EINVAL;
1018 }
1019
1020 struct auxtrace_record *intel_pt_recording_init(int *err)
1021 {
1022         struct perf_pmu *intel_pt_pmu = perf_pmu__find(INTEL_PT_PMU_NAME);
1023         struct intel_pt_recording *ptr;
1024
1025         if (!intel_pt_pmu)
1026                 return NULL;
1027
1028         ptr = zalloc(sizeof(struct intel_pt_recording));
1029         if (!ptr) {
1030                 *err = -ENOMEM;
1031                 return NULL;
1032         }
1033
1034         ptr->intel_pt_pmu = intel_pt_pmu;
1035         ptr->itr.recording_options = intel_pt_recording_options;
1036         ptr->itr.info_priv_size = intel_pt_info_priv_size;
1037         ptr->itr.info_fill = intel_pt_info_fill;
1038         ptr->itr.free = intel_pt_recording_free;
1039         ptr->itr.snapshot_start = intel_pt_snapshot_start;
1040         ptr->itr.snapshot_finish = intel_pt_snapshot_finish;
1041         ptr->itr.find_snapshot = intel_pt_find_snapshot;
1042         ptr->itr.parse_snapshot_options = intel_pt_parse_snapshot_options;
1043         ptr->itr.reference = intel_pt_reference;
1044         ptr->itr.read_finish = intel_pt_read_finish;
1045         return &ptr->itr;
1046 }