kernel/tools/perf/arch/x86/util/intel-bts.c

   1 /*
   2  * intel-bts.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 <linux/kernel.h>
  17 #include <linux/types.h>
  18 #include <linux/bitops.h>
  19 #include <linux/log2.h>
  20
  21 #include "../../util/cpumap.h"
  22 #include "../../util/evsel.h"
  23 #include "../../util/evlist.h"
  24 #include "../../util/session.h"
  25 #include "../../util/util.h"
  26 #include "../../util/pmu.h"
  27 #include "../../util/debug.h"
  28 #include "../../util/tsc.h"
  29 #include "../../util/auxtrace.h"
  30 #include "../../util/intel-bts.h"
  31
  32 #define KiB(x) ((x) * 1024)
  33 #define MiB(x) ((x) * 1024 * 1024)
  34 #define KiB_MASK(x) (KiB(x) - 1)
  35 #define MiB_MASK(x) (MiB(x) - 1)
  36
  37 #define INTEL_BTS_DFLT_SAMPLE_SIZE      KiB(4)
  38
  39 #define INTEL_BTS_MAX_SAMPLE_SIZE       KiB(60)
  40
  41 struct intel_bts_snapshot_ref {
  42         void    *ref_buf;
  43         size_t  ref_offset;
  44         bool    wrapped;
  45 };
  46
  47 struct intel_bts_recording {
  48         struct auxtrace_record          itr;
  49         struct perf_pmu                 *intel_bts_pmu;
  50         struct perf_evlist              *evlist;
  51         bool                            snapshot_mode;
  52         size_t                          snapshot_size;
  53         int                             snapshot_ref_cnt;
  54         struct intel_bts_snapshot_ref   *snapshot_refs;
  55 };
  56
  57 struct branch {
  58         u64 from;
  59         u64 to;
  60         u64 misc;
  61 };
  62
  63 static size_t intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused)
  64 {
  65         return INTEL_BTS_AUXTRACE_PRIV_SIZE;
  66 }
  67
  68 static int intel_bts_info_fill(struct auxtrace_record *itr,
  69                                struct perf_session *session,
  70                                struct auxtrace_info_event *auxtrace_info,
  71                                size_t priv_size)
  72 {
  73         struct intel_bts_recording *btsr =
  74                         container_of(itr, struct intel_bts_recording, itr);
  75         struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
  76         struct perf_event_mmap_page *pc;
  77         struct perf_tsc_conversion tc = { .time_mult = 0, };
  78         bool cap_user_time_zero = false;
  79         int err;
  80
  81         if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE)
  82                 return -EINVAL;
  83
  84         if (!session->evlist->nr_mmaps)
  85                 return -EINVAL;
  86
  87         pc = session->evlist->mmap[0].base;
  88         if (pc) {
  89                 err = perf_read_tsc_conversion(pc, &tc);
  90                 if (err) {
  91                         if (err != -EOPNOTSUPP)
  92                                 return err;
  93                 } else {
  94                         cap_user_time_zero = tc.time_mult != 0;
  95                 }
  96                 if (!cap_user_time_zero)
  97                         ui__warning("Intel BTS: TSC not available\n");
  98         }
  99
 100         auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS;
 101         auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type;
 102         auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift;
 103         auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult;
 104         auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero;
 105         auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero;
 106         auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode;
 107
 108         return 0;
 109 }
 110
 111 static int intel_bts_recording_options(struct auxtrace_record *itr,
 112                                        struct perf_evlist *evlist,
 113                                        struct record_opts *opts)
 114 {
 115         struct intel_bts_recording *btsr =
 116                         container_of(itr, struct intel_bts_recording, itr);
 117         struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
 118         struct perf_evsel *evsel, *intel_bts_evsel = NULL;
 119         const struct cpu_map *cpus = evlist->cpus;
 120         bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
 121
 122         btsr->evlist = evlist;
 123         btsr->snapshot_mode = opts->auxtrace_snapshot_mode;
 124
 125         evlist__for_each(evlist, evsel) {
 126                 if (evsel->attr.type == intel_bts_pmu->type) {
 127                         if (intel_bts_evsel) {
 128                                 pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n");
 129                                 return -EINVAL;
 130                         }
 131                         evsel->attr.freq = 0;
 132                         evsel->attr.sample_period = 1;
 133                         intel_bts_evsel = evsel;
 134                         opts->full_auxtrace = true;
 135                 }
 136         }
 137
 138         if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
 139                 pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
 140                 return -EINVAL;
 141         }
 142
 143         if (!opts->full_auxtrace)
 144                 return 0;
 145
 146         if (opts->full_auxtrace && !cpu_map__empty(cpus)) {
 147                 pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
 148                 return -EINVAL;
 149         }
 150
 151         /* Set default sizes for snapshot mode */
 152         if (opts->auxtrace_snapshot_mode) {
 153                 if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
 154                         if (privileged) {
 155                                 opts->auxtrace_mmap_pages = MiB(4) / page_size;
 156                         } else {
 157                                 opts->auxtrace_mmap_pages = KiB(128) / page_size;
 158                                 if (opts->mmap_pages == UINT_MAX)
 159                                         opts->mmap_pages = KiB(256) / page_size;
 160                         }
 161                 } else if (!opts->auxtrace_mmap_pages && !privileged &&
 162                            opts->mmap_pages == UINT_MAX) {
 163                         opts->mmap_pages = KiB(256) / page_size;
 164                 }
 165                 if (!opts->auxtrace_snapshot_size)
 166                         opts->auxtrace_snapshot_size =
 167                                 opts->auxtrace_mmap_pages * (size_t)page_size;
 168                 if (!opts->auxtrace_mmap_pages) {
 169                         size_t sz = opts->auxtrace_snapshot_size;
 170
 171                         sz = round_up(sz, page_size) / page_size;
 172                         opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
 173                 }
 174                 if (opts->auxtrace_snapshot_size >
 175                                 opts->auxtrace_mmap_pages * (size_t)page_size) {
 176                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
 177                                opts->auxtrace_snapshot_size,
 178                                opts->auxtrace_mmap_pages * (size_t)page_size);
 179                         return -EINVAL;
 180                 }
 181                 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
 182                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
 183                         return -EINVAL;
 184                 }
 185                 pr_debug2("Intel BTS snapshot size: %zu\n",
 186                           opts->auxtrace_snapshot_size);
 187         }
 188
 189         /* Set default sizes for full trace mode */
 190         if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
 191                 if (privileged) {
 192                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 193                 } else {
 194                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 195                         if (opts->mmap_pages == UINT_MAX)
 196                                 opts->mmap_pages = KiB(256) / page_size;
 197                 }
 198         }
 199
 200         /* Validate auxtrace_mmap_pages */
 201         if (opts->auxtrace_mmap_pages) {
 202                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
 203                 size_t min_sz;
 204
 205                 if (opts->auxtrace_snapshot_mode)
 206                         min_sz = KiB(4);
 207                 else
 208                         min_sz = KiB(8);
 209
 210                 if (sz < min_sz || !is_power_of_2(sz)) {
 211                         pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
 212                                min_sz / 1024);
 213                         return -EINVAL;
 214                 }
 215         }
 216
 217         if (intel_bts_evsel) {
 218                 /*
 219                  * To obtain the auxtrace buffer file descriptor, the auxtrace event
 220                  * must come first.
 221                  */
 222                 perf_evlist__to_front(evlist, intel_bts_evsel);
 223                 /*
 224                  * In the case of per-cpu mmaps, we need the CPU on the
 225                  * AUX event.
 226                  */
 227                 if (!cpu_map__empty(cpus))
 228                         perf_evsel__set_sample_bit(intel_bts_evsel, CPU);
 229         }
 230
 231         /* Add dummy event to keep tracking */
 232         if (opts->full_auxtrace) {
 233                 struct perf_evsel *tracking_evsel;
 234                 int err;
 235
 236                 err = parse_events(evlist, "dummy:u", NULL);
 237                 if (err)
 238                         return err;
 239
 240                 tracking_evsel = perf_evlist__last(evlist);
 241
 242                 perf_evlist__set_tracking_event(evlist, tracking_evsel);
 243
 244                 tracking_evsel->attr.freq = 0;
 245                 tracking_evsel->attr.sample_period = 1;
 246         }
 247
 248         return 0;
 249 }
 250
 251 static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
 252                                             struct record_opts *opts,
 253                                             const char *str)
 254 {
 255         struct intel_bts_recording *btsr =
 256                         container_of(itr, struct intel_bts_recording, itr);
 257         unsigned long long snapshot_size = 0;
 258         char *endptr;
 259
 260         if (str) {
 261                 snapshot_size = strtoull(str, &endptr, 0);
 262                 if (*endptr || snapshot_size > SIZE_MAX)
 263                         return -1;
 264         }
 265
 266         opts->auxtrace_snapshot_mode = true;
 267         opts->auxtrace_snapshot_size = snapshot_size;
 268
 269         btsr->snapshot_size = snapshot_size;
 270
 271         return 0;
 272 }
 273
 274 static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
 275 {
 276         return rdtsc();
 277 }
 278
 279 static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
 280                                          int idx)
 281 {
 282         const size_t sz = sizeof(struct intel_bts_snapshot_ref);
 283         int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
 284         struct intel_bts_snapshot_ref *refs;
 285
 286         if (!new_cnt)
 287                 new_cnt = 16;
 288
 289         while (new_cnt <= idx)
 290                 new_cnt *= 2;
 291
 292         refs = calloc(new_cnt, sz);
 293         if (!refs)
 294                 return -ENOMEM;
 295
 296         memcpy(refs, btsr->snapshot_refs, cnt * sz);
 297
 298         btsr->snapshot_refs = refs;
 299         btsr->snapshot_ref_cnt = new_cnt;
 300
 301         return 0;
 302 }
 303
 304 static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
 305 {
 306         int i;
 307
 308         for (i = 0; i < btsr->snapshot_ref_cnt; i++)
 309                 zfree(&btsr->snapshot_refs[i].ref_buf);
 310         zfree(&btsr->snapshot_refs);
 311 }
 312
 313 static void intel_bts_recording_free(struct auxtrace_record *itr)
 314 {
 315         struct intel_bts_recording *btsr =
 316                         container_of(itr, struct intel_bts_recording, itr);
 317
 318         intel_bts_free_snapshot_refs(btsr);
 319         free(btsr);
 320 }
 321
 322 static int intel_bts_snapshot_start(struct auxtrace_record *itr)
 323 {
 324         struct intel_bts_recording *btsr =
 325                         container_of(itr, struct intel_bts_recording, itr);
 326         struct perf_evsel *evsel;
 327
 328         evlist__for_each(btsr->evlist, evsel) {
 329                 if (evsel->attr.type == btsr->intel_bts_pmu->type)
 330                         return perf_evlist__disable_event(btsr->evlist, evsel);
 331         }
 332         return -EINVAL;
 333 }
 334
 335 static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
 336 {
 337         struct intel_bts_recording *btsr =
 338                         container_of(itr, struct intel_bts_recording, itr);
 339         struct perf_evsel *evsel;
 340
 341         evlist__for_each(btsr->evlist, evsel) {
 342                 if (evsel->attr.type == btsr->intel_bts_pmu->type)
 343                         return perf_evlist__enable_event(btsr->evlist, evsel);
 344         }
 345         return -EINVAL;
 346 }
 347
 348 static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
 349 {
 350         int i, a, b;
 351
 352         b = buf_size >> 3;
 353         a = b - 512;
 354         if (a < 0)
 355                 a = 0;
 356
 357         for (i = a; i < b; i++) {
 358                 if (data[i])
 359                         return true;
 360         }
 361
 362         return false;
 363 }
 364
 365 static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
 366                                    struct auxtrace_mmap *mm, unsigned char *data,
 367                                    u64 *head, u64 *old)
 368 {
 369         struct intel_bts_recording *btsr =
 370                         container_of(itr, struct intel_bts_recording, itr);
 371         bool wrapped;
 372         int err;
 373
 374         pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
 375                   __func__, idx, (size_t)*old, (size_t)*head);
 376
 377         if (idx >= btsr->snapshot_ref_cnt) {
 378                 err = intel_bts_alloc_snapshot_refs(btsr, idx);
 379                 if (err)
 380                         goto out_err;
 381         }
 382
 383         wrapped = btsr->snapshot_refs[idx].wrapped;
 384         if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) {
 385                 btsr->snapshot_refs[idx].wrapped = true;
 386                 wrapped = true;
 387         }
 388
 389         /*
 390          * In full trace mode 'head' continually increases.  However in snapshot
 391          * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
 392          * are adjusted to match the full trace case which expects that 'old' is
 393          * always less than 'head'.
 394          */
 395         if (wrapped) {
 396                 *old = *head;
 397                 *head += mm->len;
 398         } else {
 399                 if (mm->mask)
 400                         *old &= mm->mask;
 401                 else
 402                         *old %= mm->len;
 403                 if (*old > *head)
 404                         *head += mm->len;
 405         }
 406
 407         pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
 408                   __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
 409
 410         return 0;
 411
 412 out_err:
 413         pr_err("%s: failed, error %d\n", __func__, err);
 414         return err;
 415 }
 416
 417 static int intel_bts_read_finish(struct auxtrace_record *itr, int idx)
 418 {
 419         struct intel_bts_recording *btsr =
 420                         container_of(itr, struct intel_bts_recording, itr);
 421         struct perf_evsel *evsel;
 422
 423         evlist__for_each(btsr->evlist, evsel) {
 424                 if (evsel->attr.type == btsr->intel_bts_pmu->type)
 425                         return perf_evlist__enable_event_idx(btsr->evlist,
 426                                                              evsel, idx);
 427         }
 428         return -EINVAL;
 429 }
 430
 431 struct auxtrace_record *intel_bts_recording_init(int *err)
 432 {
 433         struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME);
 434         struct intel_bts_recording *btsr;
 435
 436         if (!intel_bts_pmu)
 437                 return NULL;
 438
 439         btsr = zalloc(sizeof(struct intel_bts_recording));
 440         if (!btsr) {
 441                 *err = -ENOMEM;
 442                 return NULL;
 443         }
 444
 445         btsr->intel_bts_pmu = intel_bts_pmu;
 446         btsr->itr.recording_options = intel_bts_recording_options;
 447         btsr->itr.info_priv_size = intel_bts_info_priv_size;
 448         btsr->itr.info_fill = intel_bts_info_fill;
 449         btsr->itr.free = intel_bts_recording_free;
 450         btsr->itr.snapshot_start = intel_bts_snapshot_start;
 451         btsr->itr.snapshot_finish = intel_bts_snapshot_finish;
 452         btsr->itr.find_snapshot = intel_bts_find_snapshot;
 453         btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options;
 454         btsr->itr.reference = intel_bts_reference;
 455         btsr->itr.read_finish = intel_bts_read_finish;
 456         btsr->itr.alignment = sizeof(struct branch);
 457         return &btsr->itr;
 458 }