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 psb_cyc, psb_periods, psb_period;
 194         int pos = 0;
 195         u64 config;
 196
 197         pos += scnprintf(buf + pos, sizeof(buf) - pos, "tsc");
 198
 199         if (perf_pmu__scan_file(intel_pt_pmu, "caps/psb_cyc", "%d",
 200                                 &psb_cyc) != 1)
 201                 psb_cyc = 1;
 202
 203         if (psb_cyc) {
 204                 if (perf_pmu__scan_file(intel_pt_pmu, "caps/psb_periods", "%x",
 205                                         &psb_periods) != 1)
 206                         psb_periods = 0;
 207                 if (psb_periods) {
 208                         psb_period = intel_pt_pick_bit(psb_periods, 3);
 209                         pos += scnprintf(buf + pos, sizeof(buf) - pos,
 210                                          ",psb_period=%d", psb_period);
 211                 }
 212         }
 213
 214         pr_debug2("%s default config: %s\n", intel_pt_pmu->name, buf);
 215
 216         intel_pt_parse_terms(&intel_pt_pmu->format, buf, &config);
 217
 218         return config;
 219 }
 220
 221 static int intel_pt_parse_snapshot_options(struct auxtrace_record *itr,
 222                                            struct record_opts *opts,
 223                                            const char *str)
 224 {
 225         struct intel_pt_recording *ptr =
 226                         container_of(itr, struct intel_pt_recording, itr);
 227         unsigned long long snapshot_size = 0;
 228         char *endptr;
 229
 230         if (str) {
 231                 snapshot_size = strtoull(str, &endptr, 0);
 232                 if (*endptr || snapshot_size > SIZE_MAX)
 233                         return -1;
 234         }
 235
 236         opts->auxtrace_snapshot_mode = true;
 237         opts->auxtrace_snapshot_size = snapshot_size;
 238
 239         ptr->snapshot_size = snapshot_size;
 240
 241         return 0;
 242 }
 243
 244 struct perf_event_attr *
 245 intel_pt_pmu_default_config(struct perf_pmu *intel_pt_pmu)
 246 {
 247         struct perf_event_attr *attr;
 248
 249         attr = zalloc(sizeof(struct perf_event_attr));
 250         if (!attr)
 251                 return NULL;
 252
 253         attr->config = intel_pt_default_config(intel_pt_pmu);
 254
 255         intel_pt_pmu->selectable = true;
 256
 257         return attr;
 258 }
 259
 260 static size_t intel_pt_info_priv_size(struct auxtrace_record *itr __maybe_unused)
 261 {
 262         return INTEL_PT_AUXTRACE_PRIV_SIZE;
 263 }
 264
 265 static void intel_pt_tsc_ctc_ratio(u32 *n, u32 *d)
 266 {
 267         unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0;
 268
 269         __get_cpuid(0x15, &eax, &ebx, &ecx, &edx);
 270         *n = ebx;
 271         *d = eax;
 272 }
 273
 274 static int intel_pt_info_fill(struct auxtrace_record *itr,
 275                               struct perf_session *session,
 276                               struct auxtrace_info_event *auxtrace_info,
 277                               size_t priv_size)
 278 {
 279         struct intel_pt_recording *ptr =
 280                         container_of(itr, struct intel_pt_recording, itr);
 281         struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
 282         struct perf_event_mmap_page *pc;
 283         struct perf_tsc_conversion tc = { .time_mult = 0, };
 284         bool cap_user_time_zero = false, per_cpu_mmaps;
 285         u64 tsc_bit, mtc_bit, mtc_freq_bits, cyc_bit, noretcomp_bit;
 286         u32 tsc_ctc_ratio_n, tsc_ctc_ratio_d;
 287         int err;
 288
 289         if (priv_size != INTEL_PT_AUXTRACE_PRIV_SIZE)
 290                 return -EINVAL;
 291
 292         intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
 293         intel_pt_parse_terms(&intel_pt_pmu->format, "noretcomp",
 294                              &noretcomp_bit);
 295         intel_pt_parse_terms(&intel_pt_pmu->format, "mtc", &mtc_bit);
 296         mtc_freq_bits = perf_pmu__format_bits(&intel_pt_pmu->format,
 297                                               "mtc_period");
 298         intel_pt_parse_terms(&intel_pt_pmu->format, "cyc", &cyc_bit);
 299
 300         intel_pt_tsc_ctc_ratio(&tsc_ctc_ratio_n, &tsc_ctc_ratio_d);
 301
 302         if (!session->evlist->nr_mmaps)
 303                 return -EINVAL;
 304
 305         pc = session->evlist->mmap[0].base;
 306         if (pc) {
 307                 err = perf_read_tsc_conversion(pc, &tc);
 308                 if (err) {
 309                         if (err != -EOPNOTSUPP)
 310                                 return err;
 311                 } else {
 312                         cap_user_time_zero = tc.time_mult != 0;
 313                 }
 314                 if (!cap_user_time_zero)
 315                         ui__warning("Intel Processor Trace: TSC not available\n");
 316         }
 317
 318         per_cpu_mmaps = !cpu_map__empty(session->evlist->cpus);
 319
 320         auxtrace_info->type = PERF_AUXTRACE_INTEL_PT;
 321         auxtrace_info->priv[INTEL_PT_PMU_TYPE] = intel_pt_pmu->type;
 322         auxtrace_info->priv[INTEL_PT_TIME_SHIFT] = tc.time_shift;
 323         auxtrace_info->priv[INTEL_PT_TIME_MULT] = tc.time_mult;
 324         auxtrace_info->priv[INTEL_PT_TIME_ZERO] = tc.time_zero;
 325         auxtrace_info->priv[INTEL_PT_CAP_USER_TIME_ZERO] = cap_user_time_zero;
 326         auxtrace_info->priv[INTEL_PT_TSC_BIT] = tsc_bit;
 327         auxtrace_info->priv[INTEL_PT_NORETCOMP_BIT] = noretcomp_bit;
 328         auxtrace_info->priv[INTEL_PT_HAVE_SCHED_SWITCH] = ptr->have_sched_switch;
 329         auxtrace_info->priv[INTEL_PT_SNAPSHOT_MODE] = ptr->snapshot_mode;
 330         auxtrace_info->priv[INTEL_PT_PER_CPU_MMAPS] = per_cpu_mmaps;
 331         auxtrace_info->priv[INTEL_PT_MTC_BIT] = mtc_bit;
 332         auxtrace_info->priv[INTEL_PT_MTC_FREQ_BITS] = mtc_freq_bits;
 333         auxtrace_info->priv[INTEL_PT_TSC_CTC_N] = tsc_ctc_ratio_n;
 334         auxtrace_info->priv[INTEL_PT_TSC_CTC_D] = tsc_ctc_ratio_d;
 335         auxtrace_info->priv[INTEL_PT_CYC_BIT] = cyc_bit;
 336
 337         return 0;
 338 }
 339
 340 static int intel_pt_track_switches(struct perf_evlist *evlist)
 341 {
 342         const char *sched_switch = "sched:sched_switch";
 343         struct perf_evsel *evsel;
 344         int err;
 345
 346         if (!perf_evlist__can_select_event(evlist, sched_switch))
 347                 return -EPERM;
 348
 349         err = parse_events(evlist, sched_switch, NULL);
 350         if (err) {
 351                 pr_debug2("%s: failed to parse %s, error %d\n",
 352                           __func__, sched_switch, err);
 353                 return err;
 354         }
 355
 356         evsel = perf_evlist__last(evlist);
 357
 358         perf_evsel__set_sample_bit(evsel, CPU);
 359         perf_evsel__set_sample_bit(evsel, TIME);
 360
 361         evsel->system_wide = true;
 362         evsel->no_aux_samples = true;
 363         evsel->immediate = true;
 364
 365         return 0;
 366 }
 367
 368 static void intel_pt_valid_str(char *str, size_t len, u64 valid)
 369 {
 370         unsigned int val, last = 0, state = 1;
 371         int p = 0;
 372
 373         str[0] = '\0';
 374
 375         for (val = 0; val <= 64; val++, valid >>= 1) {
 376                 if (valid & 1) {
 377                         last = val;
 378                         switch (state) {
 379                         case 0:
 380                                 p += scnprintf(str + p, len - p, ",");
 381                                 /* Fall through */
 382                         case 1:
 383                                 p += scnprintf(str + p, len - p, "%u", val);
 384                                 state = 2;
 385                                 break;
 386                         case 2:
 387                                 state = 3;
 388                                 break;
 389                         case 3:
 390                                 state = 4;
 391                                 break;
 392                         default:
 393                                 break;
 394                         }
 395                 } else {
 396                         switch (state) {
 397                         case 3:
 398                                 p += scnprintf(str + p, len - p, ",%u", last);
 399                                 state = 0;
 400                                 break;
 401                         case 4:
 402                                 p += scnprintf(str + p, len - p, "-%u", last);
 403                                 state = 0;
 404                                 break;
 405                         default:
 406                                 break;
 407                         }
 408                         if (state != 1)
 409                                 state = 0;
 410                 }
 411         }
 412 }
 413
 414 static int intel_pt_val_config_term(struct perf_pmu *intel_pt_pmu,
 415                                     const char *caps, const char *name,
 416                                     const char *supported, u64 config)
 417 {
 418         char valid_str[256];
 419         unsigned int shift;
 420         unsigned long long valid;
 421         u64 bits;
 422         int ok;
 423
 424         if (perf_pmu__scan_file(intel_pt_pmu, caps, "%llx", &valid) != 1)
 425                 valid = 0;
 426
 427         if (supported &&
 428             perf_pmu__scan_file(intel_pt_pmu, supported, "%d", &ok) == 1 && !ok)
 429                 valid = 0;
 430
 431         valid |= 1;
 432
 433         bits = perf_pmu__format_bits(&intel_pt_pmu->format, name);
 434
 435         config &= bits;
 436
 437         for (shift = 0; bits && !(bits & 1); shift++)
 438                 bits >>= 1;
 439
 440         config >>= shift;
 441
 442         if (config > 63)
 443                 goto out_err;
 444
 445         if (valid & (1 << config))
 446                 return 0;
 447 out_err:
 448         intel_pt_valid_str(valid_str, sizeof(valid_str), valid);
 449         pr_err("Invalid %s for %s. Valid values are: %s\n",
 450                name, INTEL_PT_PMU_NAME, valid_str);
 451         return -EINVAL;
 452 }
 453
 454 static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu,
 455                                     struct perf_evsel *evsel)
 456 {
 457         if (!evsel)
 458                 return 0;
 459
 460         return intel_pt_val_config_term(intel_pt_pmu, "caps/psb_periods",
 461                                         "psb_period", "caps/psb_cyc",
 462                                         evsel->attr.config);
 463 }
 464
 465 static int intel_pt_recording_options(struct auxtrace_record *itr,
 466                                       struct perf_evlist *evlist,
 467                                       struct record_opts *opts)
 468 {
 469         struct intel_pt_recording *ptr =
 470                         container_of(itr, struct intel_pt_recording, itr);
 471         struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
 472         bool have_timing_info;
 473         struct perf_evsel *evsel, *intel_pt_evsel = NULL;
 474         const struct cpu_map *cpus = evlist->cpus;
 475         bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
 476         u64 tsc_bit;
 477         int err;
 478
 479         ptr->evlist = evlist;
 480         ptr->snapshot_mode = opts->auxtrace_snapshot_mode;
 481
 482         evlist__for_each(evlist, evsel) {
 483                 if (evsel->attr.type == intel_pt_pmu->type) {
 484                         if (intel_pt_evsel) {
 485                                 pr_err("There may be only one " INTEL_PT_PMU_NAME " event\n");
 486                                 return -EINVAL;
 487                         }
 488                         evsel->attr.freq = 0;
 489                         evsel->attr.sample_period = 1;
 490                         intel_pt_evsel = evsel;
 491                         opts->full_auxtrace = true;
 492                 }
 493         }
 494
 495         if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
 496                 pr_err("Snapshot mode (-S option) requires " INTEL_PT_PMU_NAME " PMU event (-e " INTEL_PT_PMU_NAME ")\n");
 497                 return -EINVAL;
 498         }
 499
 500         if (opts->use_clockid) {
 501                 pr_err("Cannot use clockid (-k option) with " INTEL_PT_PMU_NAME "\n");
 502                 return -EINVAL;
 503         }
 504
 505         if (!opts->full_auxtrace)
 506                 return 0;
 507
 508         err = intel_pt_validate_config(intel_pt_pmu, intel_pt_evsel);
 509         if (err)
 510                 return err;
 511
 512         /* Set default sizes for snapshot mode */
 513         if (opts->auxtrace_snapshot_mode) {
 514                 size_t psb_period = intel_pt_psb_period(intel_pt_pmu, evlist);
 515
 516                 if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
 517                         if (privileged) {
 518                                 opts->auxtrace_mmap_pages = MiB(4) / page_size;
 519                         } else {
 520                                 opts->auxtrace_mmap_pages = KiB(128) / page_size;
 521                                 if (opts->mmap_pages == UINT_MAX)
 522                                         opts->mmap_pages = KiB(256) / page_size;
 523                         }
 524                 } else if (!opts->auxtrace_mmap_pages && !privileged &&
 525                            opts->mmap_pages == UINT_MAX) {
 526                         opts->mmap_pages = KiB(256) / page_size;
 527                 }
 528                 if (!opts->auxtrace_snapshot_size)
 529                         opts->auxtrace_snapshot_size =
 530                                 opts->auxtrace_mmap_pages * (size_t)page_size;
 531                 if (!opts->auxtrace_mmap_pages) {
 532                         size_t sz = opts->auxtrace_snapshot_size;
 533
 534                         sz = round_up(sz, page_size) / page_size;
 535                         opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
 536                 }
 537                 if (opts->auxtrace_snapshot_size >
 538                                 opts->auxtrace_mmap_pages * (size_t)page_size) {
 539                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
 540                                opts->auxtrace_snapshot_size,
 541                                opts->auxtrace_mmap_pages * (size_t)page_size);
 542                         return -EINVAL;
 543                 }
 544                 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
 545                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
 546                         return -EINVAL;
 547                 }
 548                 pr_debug2("Intel PT snapshot size: %zu\n",
 549                           opts->auxtrace_snapshot_size);
 550                 if (psb_period &&
 551                     opts->auxtrace_snapshot_size <= psb_period +
 552                                                   INTEL_PT_PSB_PERIOD_NEAR)
 553                         ui__warning("Intel PT snapshot size (%zu) may be too small for PSB period (%zu)\n",
 554                                     opts->auxtrace_snapshot_size, psb_period);
 555         }
 556
 557         /* Set default sizes for full trace mode */
 558         if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
 559                 if (privileged) {
 560                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 561                 } else {
 562                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 563                         if (opts->mmap_pages == UINT_MAX)
 564                                 opts->mmap_pages = KiB(256) / page_size;
 565                 }
 566         }
 567
 568         /* Validate auxtrace_mmap_pages */
 569         if (opts->auxtrace_mmap_pages) {
 570                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
 571                 size_t min_sz;
 572
 573                 if (opts->auxtrace_snapshot_mode)
 574                         min_sz = KiB(4);
 575                 else
 576                         min_sz = KiB(8);
 577
 578                 if (sz < min_sz || !is_power_of_2(sz)) {
 579                         pr_err("Invalid mmap size for Intel Processor Trace: must be at least %zuKiB and a power of 2\n",
 580                                min_sz / 1024);
 581                         return -EINVAL;
 582                 }
 583         }
 584
 585         intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
 586
 587         if (opts->full_auxtrace && (intel_pt_evsel->attr.config & tsc_bit))
 588                 have_timing_info = true;
 589         else
 590                 have_timing_info = false;
 591
 592         /*
 593          * Per-cpu recording needs sched_switch events to distinguish different
 594          * threads.
 595          */
 596         if (have_timing_info && !cpu_map__empty(cpus)) {
 597                 err = intel_pt_track_switches(evlist);
 598                 if (err == -EPERM)
 599                         pr_debug2("Unable to select sched:sched_switch\n");
 600                 else if (err)
 601                         return err;
 602                 else
 603                         ptr->have_sched_switch = 1;
 604         }
 605
 606         if (intel_pt_evsel) {
 607                 /*
 608                  * To obtain the auxtrace buffer file descriptor, the auxtrace
 609                  * event must come first.
 610                  */
 611                 perf_evlist__to_front(evlist, intel_pt_evsel);
 612                 /*
 613                  * In the case of per-cpu mmaps, we need the CPU on the
 614                  * AUX event.
 615                  */
 616                 if (!cpu_map__empty(cpus))
 617                         perf_evsel__set_sample_bit(intel_pt_evsel, CPU);
 618         }
 619
 620         /* Add dummy event to keep tracking */
 621         if (opts->full_auxtrace) {
 622                 struct perf_evsel *tracking_evsel;
 623
 624                 err = parse_events(evlist, "dummy:u", NULL);
 625                 if (err)
 626                         return err;
 627
 628                 tracking_evsel = perf_evlist__last(evlist);
 629
 630                 perf_evlist__set_tracking_event(evlist, tracking_evsel);
 631
 632                 tracking_evsel->attr.freq = 0;
 633                 tracking_evsel->attr.sample_period = 1;
 634
 635                 /* In per-cpu case, always need the time of mmap events etc */
 636                 if (!cpu_map__empty(cpus))
 637                         perf_evsel__set_sample_bit(tracking_evsel, TIME);
 638         }
 639
 640         /*
 641          * Warn the user when we do not have enough information to decode i.e.
 642          * per-cpu with no sched_switch (except workload-only).
 643          */
 644         if (!ptr->have_sched_switch && !cpu_map__empty(cpus) &&
 645             !target__none(&opts->target))
 646                 ui__warning("Intel Processor Trace decoding will not be possible except for kernel tracing!\n");
 647
 648         return 0;
 649 }
 650
 651 static int intel_pt_snapshot_start(struct auxtrace_record *itr)
 652 {
 653         struct intel_pt_recording *ptr =
 654                         container_of(itr, struct intel_pt_recording, itr);
 655         struct perf_evsel *evsel;
 656
 657         evlist__for_each(ptr->evlist, evsel) {
 658                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
 659                         return perf_evlist__disable_event(ptr->evlist, evsel);
 660         }
 661         return -EINVAL;
 662 }
 663
 664 static int intel_pt_snapshot_finish(struct auxtrace_record *itr)
 665 {
 666         struct intel_pt_recording *ptr =
 667                         container_of(itr, struct intel_pt_recording, itr);
 668         struct perf_evsel *evsel;
 669
 670         evlist__for_each(ptr->evlist, evsel) {
 671                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
 672                         return perf_evlist__enable_event(ptr->evlist, evsel);
 673         }
 674         return -EINVAL;
 675 }
 676
 677 static int intel_pt_alloc_snapshot_refs(struct intel_pt_recording *ptr, int idx)
 678 {
 679         const size_t sz = sizeof(struct intel_pt_snapshot_ref);
 680         int cnt = ptr->snapshot_ref_cnt, new_cnt = cnt * 2;
 681         struct intel_pt_snapshot_ref *refs;
 682
 683         if (!new_cnt)
 684                 new_cnt = 16;
 685
 686         while (new_cnt <= idx)
 687                 new_cnt *= 2;
 688
 689         refs = calloc(new_cnt, sz);
 690         if (!refs)
 691                 return -ENOMEM;
 692
 693         memcpy(refs, ptr->snapshot_refs, cnt * sz);
 694
 695         ptr->snapshot_refs = refs;
 696         ptr->snapshot_ref_cnt = new_cnt;
 697
 698         return 0;
 699 }
 700
 701 static void intel_pt_free_snapshot_refs(struct intel_pt_recording *ptr)
 702 {
 703         int i;
 704
 705         for (i = 0; i < ptr->snapshot_ref_cnt; i++)
 706                 zfree(&ptr->snapshot_refs[i].ref_buf);
 707         zfree(&ptr->snapshot_refs);
 708 }
 709
 710 static void intel_pt_recording_free(struct auxtrace_record *itr)
 711 {
 712         struct intel_pt_recording *ptr =
 713                         container_of(itr, struct intel_pt_recording, itr);
 714
 715         intel_pt_free_snapshot_refs(ptr);
 716         free(ptr);
 717 }
 718
 719 static int intel_pt_alloc_snapshot_ref(struct intel_pt_recording *ptr, int idx,
 720                                        size_t snapshot_buf_size)
 721 {
 722         size_t ref_buf_size = ptr->snapshot_ref_buf_size;
 723         void *ref_buf;
 724
 725         ref_buf = zalloc(ref_buf_size);
 726         if (!ref_buf)
 727                 return -ENOMEM;
 728
 729         ptr->snapshot_refs[idx].ref_buf = ref_buf;
 730         ptr->snapshot_refs[idx].ref_offset = snapshot_buf_size - ref_buf_size;
 731
 732         return 0;
 733 }
 734
 735 static size_t intel_pt_snapshot_ref_buf_size(struct intel_pt_recording *ptr,
 736                                              size_t snapshot_buf_size)
 737 {
 738         const size_t max_size = 256 * 1024;
 739         size_t buf_size = 0, psb_period;
 740
 741         if (ptr->snapshot_size <= 64 * 1024)
 742                 return 0;
 743
 744         psb_period = intel_pt_psb_period(ptr->intel_pt_pmu, ptr->evlist);
 745         if (psb_period)
 746                 buf_size = psb_period * 2;
 747
 748         if (!buf_size || buf_size > max_size)
 749                 buf_size = max_size;
 750
 751         if (buf_size >= snapshot_buf_size)
 752                 return 0;
 753
 754         if (buf_size >= ptr->snapshot_size / 2)
 755                 return 0;
 756
 757         return buf_size;
 758 }
 759
 760 static int intel_pt_snapshot_init(struct intel_pt_recording *ptr,
 761                                   size_t snapshot_buf_size)
 762 {
 763         if (ptr->snapshot_init_done)
 764                 return 0;
 765
 766         ptr->snapshot_init_done = true;
 767
 768         ptr->snapshot_ref_buf_size = intel_pt_snapshot_ref_buf_size(ptr,
 769                                                         snapshot_buf_size);
 770
 771         return 0;
 772 }
 773
 774 /**
 775  * intel_pt_compare_buffers - compare bytes in a buffer to a circular buffer.
 776  * @buf1: first buffer
 777  * @compare_size: number of bytes to compare
 778  * @buf2: second buffer (a circular buffer)
 779  * @offs2: offset in second buffer
 780  * @buf2_size: size of second buffer
 781  *
 782  * The comparison allows for the possibility that the bytes to compare in the
 783  * circular buffer are not contiguous.  It is assumed that @compare_size <=
 784  * @buf2_size.  This function returns %false if the bytes are identical, %true
 785  * otherwise.
 786  */
 787 static bool intel_pt_compare_buffers(void *buf1, size_t compare_size,
 788                                      void *buf2, size_t offs2, size_t buf2_size)
 789 {
 790         size_t end2 = offs2 + compare_size, part_size;
 791
 792         if (end2 <= buf2_size)
 793                 return memcmp(buf1, buf2 + offs2, compare_size);
 794
 795         part_size = end2 - buf2_size;
 796         if (memcmp(buf1, buf2 + offs2, part_size))
 797                 return true;
 798
 799         compare_size -= part_size;
 800
 801         return memcmp(buf1 + part_size, buf2, compare_size);
 802 }
 803
 804 static bool intel_pt_compare_ref(void *ref_buf, size_t ref_offset,
 805                                  size_t ref_size, size_t buf_size,
 806                                  void *data, size_t head)
 807 {
 808         size_t ref_end = ref_offset + ref_size;
 809
 810         if (ref_end > buf_size) {
 811                 if (head > ref_offset || head < ref_end - buf_size)
 812                         return true;
 813         } else if (head > ref_offset && head < ref_end) {
 814                 return true;
 815         }
 816
 817         return intel_pt_compare_buffers(ref_buf, ref_size, data, ref_offset,
 818                                         buf_size);
 819 }
 820
 821 static void intel_pt_copy_ref(void *ref_buf, size_t ref_size, size_t buf_size,
 822                               void *data, size_t head)
 823 {
 824         if (head >= ref_size) {
 825                 memcpy(ref_buf, data + head - ref_size, ref_size);
 826         } else {
 827                 memcpy(ref_buf, data, head);
 828                 ref_size -= head;
 829                 memcpy(ref_buf + head, data + buf_size - ref_size, ref_size);
 830         }
 831 }
 832
 833 static bool intel_pt_wrapped(struct intel_pt_recording *ptr, int idx,
 834                              struct auxtrace_mmap *mm, unsigned char *data,
 835                              u64 head)
 836 {
 837         struct intel_pt_snapshot_ref *ref = &ptr->snapshot_refs[idx];
 838         bool wrapped;
 839
 840         wrapped = intel_pt_compare_ref(ref->ref_buf, ref->ref_offset,
 841                                        ptr->snapshot_ref_buf_size, mm->len,
 842                                        data, head);
 843
 844         intel_pt_copy_ref(ref->ref_buf, ptr->snapshot_ref_buf_size, mm->len,
 845                           data, head);
 846
 847         return wrapped;
 848 }
 849
 850 static bool intel_pt_first_wrap(u64 *data, size_t buf_size)
 851 {
 852         int i, a, b;
 853
 854         b = buf_size >> 3;
 855         a = b - 512;
 856         if (a < 0)
 857                 a = 0;
 858
 859         for (i = a; i < b; i++) {
 860                 if (data[i])
 861                         return true;
 862         }
 863
 864         return false;
 865 }
 866
 867 static int intel_pt_find_snapshot(struct auxtrace_record *itr, int idx,
 868                                   struct auxtrace_mmap *mm, unsigned char *data,
 869                                   u64 *head, u64 *old)
 870 {
 871         struct intel_pt_recording *ptr =
 872                         container_of(itr, struct intel_pt_recording, itr);
 873         bool wrapped;
 874         int err;
 875
 876         pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
 877                   __func__, idx, (size_t)*old, (size_t)*head);
 878
 879         err = intel_pt_snapshot_init(ptr, mm->len);
 880         if (err)
 881                 goto out_err;
 882
 883         if (idx >= ptr->snapshot_ref_cnt) {
 884                 err = intel_pt_alloc_snapshot_refs(ptr, idx);
 885                 if (err)
 886                         goto out_err;
 887         }
 888
 889         if (ptr->snapshot_ref_buf_size) {
 890                 if (!ptr->snapshot_refs[idx].ref_buf) {
 891                         err = intel_pt_alloc_snapshot_ref(ptr, idx, mm->len);
 892                         if (err)
 893                                 goto out_err;
 894                 }
 895                 wrapped = intel_pt_wrapped(ptr, idx, mm, data, *head);
 896         } else {
 897                 wrapped = ptr->snapshot_refs[idx].wrapped;
 898                 if (!wrapped && intel_pt_first_wrap((u64 *)data, mm->len)) {
 899                         ptr->snapshot_refs[idx].wrapped = true;
 900                         wrapped = true;
 901                 }
 902         }
 903
 904         /*
 905          * In full trace mode 'head' continually increases.  However in snapshot
 906          * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
 907          * are adjusted to match the full trace case which expects that 'old' is
 908          * always less than 'head'.
 909          */
 910         if (wrapped) {
 911                 *old = *head;
 912                 *head += mm->len;
 913         } else {
 914                 if (mm->mask)
 915                         *old &= mm->mask;
 916                 else
 917                         *old %= mm->len;
 918                 if (*old > *head)
 919                         *head += mm->len;
 920         }
 921
 922         pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
 923                   __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
 924
 925         return 0;
 926
 927 out_err:
 928         pr_err("%s: failed, error %d\n", __func__, err);
 929         return err;
 930 }
 931
 932 static u64 intel_pt_reference(struct auxtrace_record *itr __maybe_unused)
 933 {
 934         return rdtsc();
 935 }
 936
 937 static int intel_pt_read_finish(struct auxtrace_record *itr, int idx)
 938 {
 939         struct intel_pt_recording *ptr =
 940                         container_of(itr, struct intel_pt_recording, itr);
 941         struct perf_evsel *evsel;
 942
 943         evlist__for_each(ptr->evlist, evsel) {
 944                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
 945                         return perf_evlist__enable_event_idx(ptr->evlist, evsel,
 946                                                              idx);
 947         }
 948         return -EINVAL;
 949 }
 950
 951 struct auxtrace_record *intel_pt_recording_init(int *err)
 952 {
 953         struct perf_pmu *intel_pt_pmu = perf_pmu__find(INTEL_PT_PMU_NAME);
 954         struct intel_pt_recording *ptr;
 955
 956         if (!intel_pt_pmu)
 957                 return NULL;
 958
 959         ptr = zalloc(sizeof(struct intel_pt_recording));
 960         if (!ptr) {
 961                 *err = -ENOMEM;
 962                 return NULL;
 963         }
 964
 965         ptr->intel_pt_pmu = intel_pt_pmu;
 966         ptr->itr.recording_options = intel_pt_recording_options;
 967         ptr->itr.info_priv_size = intel_pt_info_priv_size;
 968         ptr->itr.info_fill = intel_pt_info_fill;
 969         ptr->itr.free = intel_pt_recording_free;
 970         ptr->itr.snapshot_start = intel_pt_snapshot_start;
 971         ptr->itr.snapshot_finish = intel_pt_snapshot_finish;
 972         ptr->itr.find_snapshot = intel_pt_find_snapshot;
 973         ptr->itr.parse_snapshot_options = intel_pt_parse_snapshot_options;
 974         ptr->itr.reference = intel_pt_reference;
 975         ptr->itr.read_finish = intel_pt_read_finish;
 976         return &ptr->itr;
 977 }