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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * intel-bts.c: Intel Processor Trace support
   4  * Copyright (c) 2013-2015, Intel Corporation.
   5  */
   6
   7 #include <errno.h>
   8 #include <linux/kernel.h>
   9 #include <linux/types.h>
  10 #include <linux/bitops.h>
  11 #include <linux/log2.h>
  12 #include <linux/zalloc.h>
  13
  14 #include "../../../util/cpumap.h"
  15 #include "../../../util/event.h"
  16 #include "../../../util/evsel.h"
  17 #include "../../../util/evlist.h"
  18 #include "../../../util/mmap.h"
  19 #include "../../../util/session.h"
  20 #include "../../../util/pmu.h"
  21 #include "../../../util/debug.h"
  22 #include "../../../util/record.h"
  23 #include "../../../util/tsc.h"
  24 #include "../../../util/auxtrace.h"
  25 #include "../../../util/intel-bts.h"
  26 #include <internal/lib.h> // page_size
  27
  28 #define KiB(x) ((x) * 1024)
  29 #define MiB(x) ((x) * 1024 * 1024)
  30 #define KiB_MASK(x) (KiB(x) - 1)
  31 #define MiB_MASK(x) (MiB(x) - 1)
  32
  33 struct intel_bts_snapshot_ref {
  34         void    *ref_buf;
  35         size_t  ref_offset;
  36         bool    wrapped;
  37 };
  38
  39 struct intel_bts_recording {
  40         struct auxtrace_record          itr;
  41         struct perf_pmu                 *intel_bts_pmu;
  42         struct evlist           *evlist;
  43         bool                            snapshot_mode;
  44         size_t                          snapshot_size;
  45         int                             snapshot_ref_cnt;
  46         struct intel_bts_snapshot_ref   *snapshot_refs;
  47 };
  48
  49 struct branch {
  50         u64 from;
  51         u64 to;
  52         u64 misc;
  53 };
  54
  55 static size_t
  56 intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused,
  57                          struct evlist *evlist __maybe_unused)
  58 {
  59         return INTEL_BTS_AUXTRACE_PRIV_SIZE;
  60 }
  61
  62 static int intel_bts_info_fill(struct auxtrace_record *itr,
  63                                struct perf_session *session,
  64                                struct perf_record_auxtrace_info *auxtrace_info,
  65                                size_t priv_size)
  66 {
  67         struct intel_bts_recording *btsr =
  68                         container_of(itr, struct intel_bts_recording, itr);
  69         struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
  70         struct perf_event_mmap_page *pc;
  71         struct perf_tsc_conversion tc = { .time_mult = 0, };
  72         bool cap_user_time_zero = false;
  73         int err;
  74
  75         if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE)
  76                 return -EINVAL;
  77
  78         if (!session->evlist->core.nr_mmaps)
  79                 return -EINVAL;
  80
  81         pc = session->evlist->mmap[0].core.base;
  82         if (pc) {
  83                 err = perf_read_tsc_conversion(pc, &tc);
  84                 if (err) {
  85                         if (err != -EOPNOTSUPP)
  86                                 return err;
  87                 } else {
  88                         cap_user_time_zero = tc.time_mult != 0;
  89                 }
  90                 if (!cap_user_time_zero)
  91                         ui__warning("Intel BTS: TSC not available\n");
  92         }
  93
  94         auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS;
  95         auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type;
  96         auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift;
  97         auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult;
  98         auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero;
  99         auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero;
 100         auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode;
 101
 102         return 0;
 103 }
 104
 105 static int intel_bts_recording_options(struct auxtrace_record *itr,
 106                                        struct evlist *evlist,
 107                                        struct record_opts *opts)
 108 {
 109         struct intel_bts_recording *btsr =
 110                         container_of(itr, struct intel_bts_recording, itr);
 111         struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
 112         struct evsel *evsel, *intel_bts_evsel = NULL;
 113         const struct perf_cpu_map *cpus = evlist->core.cpus;
 114         bool privileged = perf_event_paranoid_check(-1);
 115
 116         if (opts->auxtrace_sample_mode) {
 117                 pr_err("Intel BTS does not support AUX area sampling\n");
 118                 return -EINVAL;
 119         }
 120
 121         btsr->evlist = evlist;
 122         btsr->snapshot_mode = opts->auxtrace_snapshot_mode;
 123
 124         evlist__for_each_entry(evlist, evsel) {
 125                 if (evsel->core.attr.type == intel_bts_pmu->type) {
 126                         if (intel_bts_evsel) {
 127                                 pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n");
 128                                 return -EINVAL;
 129                         }
 130                         evsel->core.attr.freq = 0;
 131                         evsel->core.attr.sample_period = 1;
 132                         intel_bts_evsel = evsel;
 133                         opts->full_auxtrace = true;
 134                 }
 135         }
 136
 137         if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
 138                 pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
 139                 return -EINVAL;
 140         }
 141
 142         if (!opts->full_auxtrace)
 143                 return 0;
 144
 145         if (opts->full_auxtrace && !perf_cpu_map__empty(cpus)) {
 146                 pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
 147                 return -EINVAL;
 148         }
 149
 150         /* Set default sizes for snapshot mode */
 151         if (opts->auxtrace_snapshot_mode) {
 152                 if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
 153                         if (privileged) {
 154                                 opts->auxtrace_mmap_pages = MiB(4) / page_size;
 155                         } else {
 156                                 opts->auxtrace_mmap_pages = KiB(128) / page_size;
 157                                 if (opts->mmap_pages == UINT_MAX)
 158                                         opts->mmap_pages = KiB(256) / page_size;
 159                         }
 160                 } else if (!opts->auxtrace_mmap_pages && !privileged &&
 161                            opts->mmap_pages == UINT_MAX) {
 162                         opts->mmap_pages = KiB(256) / page_size;
 163                 }
 164                 if (!opts->auxtrace_snapshot_size)
 165                         opts->auxtrace_snapshot_size =
 166                                 opts->auxtrace_mmap_pages * (size_t)page_size;
 167                 if (!opts->auxtrace_mmap_pages) {
 168                         size_t sz = opts->auxtrace_snapshot_size;
 169
 170                         sz = round_up(sz, page_size) / page_size;
 171                         opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
 172                 }
 173                 if (opts->auxtrace_snapshot_size >
 174                                 opts->auxtrace_mmap_pages * (size_t)page_size) {
 175                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
 176                                opts->auxtrace_snapshot_size,
 177                                opts->auxtrace_mmap_pages * (size_t)page_size);
 178                         return -EINVAL;
 179                 }
 180                 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
 181                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
 182                         return -EINVAL;
 183                 }
 184                 pr_debug2("Intel BTS snapshot size: %zu\n",
 185                           opts->auxtrace_snapshot_size);
 186         }
 187
 188         /* Set default sizes for full trace mode */
 189         if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
 190                 if (privileged) {
 191                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 192                 } else {
 193                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 194                         if (opts->mmap_pages == UINT_MAX)
 195                                 opts->mmap_pages = KiB(256) / page_size;
 196                 }
 197         }
 198
 199         /* Validate auxtrace_mmap_pages */
 200         if (opts->auxtrace_mmap_pages) {
 201                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
 202                 size_t min_sz;
 203
 204                 if (opts->auxtrace_snapshot_mode)
 205                         min_sz = KiB(4);
 206                 else
 207                         min_sz = KiB(8);
 208
 209                 if (sz < min_sz || !is_power_of_2(sz)) {
 210                         pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
 211                                min_sz / 1024);
 212                         return -EINVAL;
 213                 }
 214         }
 215
 216         if (intel_bts_evsel) {
 217                 /*
 218                  * To obtain the auxtrace buffer file descriptor, the auxtrace event
 219                  * must come first.
 220                  */
 221                 evlist__to_front(evlist, intel_bts_evsel);
 222                 /*
 223                  * In the case of per-cpu mmaps, we need the CPU on the
 224                  * AUX event.
 225                  */
 226                 if (!perf_cpu_map__empty(cpus))
 227                         evsel__set_sample_bit(intel_bts_evsel, CPU);
 228         }
 229
 230         /* Add dummy event to keep tracking */
 231         if (opts->full_auxtrace) {
 232                 struct evsel *tracking_evsel;
 233                 int err;
 234
 235                 err = parse_events(evlist, "dummy:u", NULL);
 236                 if (err)
 237                         return err;
 238
 239                 tracking_evsel = evlist__last(evlist);
 240
 241                 evlist__set_tracking_event(evlist, tracking_evsel);
 242
 243                 tracking_evsel->core.attr.freq = 0;
 244                 tracking_evsel->core.attr.sample_period = 1;
 245         }
 246
 247         return 0;
 248 }
 249
 250 static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
 251                                             struct record_opts *opts,
 252                                             const char *str)
 253 {
 254         struct intel_bts_recording *btsr =
 255                         container_of(itr, struct intel_bts_recording, itr);
 256         unsigned long long snapshot_size = 0;
 257         char *endptr;
 258
 259         if (str) {
 260                 snapshot_size = strtoull(str, &endptr, 0);
 261                 if (*endptr || snapshot_size > SIZE_MAX)
 262                         return -1;
 263         }
 264
 265         opts->auxtrace_snapshot_mode = true;
 266         opts->auxtrace_snapshot_size = snapshot_size;
 267
 268         btsr->snapshot_size = snapshot_size;
 269
 270         return 0;
 271 }
 272
 273 static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
 274 {
 275         return rdtsc();
 276 }
 277
 278 static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
 279                                          int idx)
 280 {
 281         const size_t sz = sizeof(struct intel_bts_snapshot_ref);
 282         int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
 283         struct intel_bts_snapshot_ref *refs;
 284
 285         if (!new_cnt)
 286                 new_cnt = 16;
 287
 288         while (new_cnt <= idx)
 289                 new_cnt *= 2;
 290
 291         refs = calloc(new_cnt, sz);
 292         if (!refs)
 293                 return -ENOMEM;
 294
 295         memcpy(refs, btsr->snapshot_refs, cnt * sz);
 296
 297         btsr->snapshot_refs = refs;
 298         btsr->snapshot_ref_cnt = new_cnt;
 299
 300         return 0;
 301 }
 302
 303 static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
 304 {
 305         int i;
 306
 307         for (i = 0; i < btsr->snapshot_ref_cnt; i++)
 308                 zfree(&btsr->snapshot_refs[i].ref_buf);
 309         zfree(&btsr->snapshot_refs);
 310 }
 311
 312 static void intel_bts_recording_free(struct auxtrace_record *itr)
 313 {
 314         struct intel_bts_recording *btsr =
 315                         container_of(itr, struct intel_bts_recording, itr);
 316
 317         intel_bts_free_snapshot_refs(btsr);
 318         free(btsr);
 319 }
 320
 321 static int intel_bts_snapshot_start(struct auxtrace_record *itr)
 322 {
 323         struct intel_bts_recording *btsr =
 324                         container_of(itr, struct intel_bts_recording, itr);
 325         struct evsel *evsel;
 326
 327         evlist__for_each_entry(btsr->evlist, evsel) {
 328                 if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
 329                         return evsel__disable(evsel);
 330         }
 331         return -EINVAL;
 332 }
 333
 334 static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
 335 {
 336         struct intel_bts_recording *btsr =
 337                         container_of(itr, struct intel_bts_recording, itr);
 338         struct evsel *evsel;
 339
 340         evlist__for_each_entry(btsr->evlist, evsel) {
 341                 if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
 342                         return evsel__enable(evsel);
 343         }
 344         return -EINVAL;
 345 }
 346
 347 static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
 348 {
 349         int i, a, b;
 350
 351         b = buf_size >> 3;
 352         a = b - 512;
 353         if (a < 0)
 354                 a = 0;
 355
 356         for (i = a; i < b; i++) {
 357                 if (data[i])
 358                         return true;
 359         }
 360
 361         return false;
 362 }
 363
 364 static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
 365                                    struct auxtrace_mmap *mm, unsigned char *data,
 366                                    u64 *head, u64 *old)
 367 {
 368         struct intel_bts_recording *btsr =
 369                         container_of(itr, struct intel_bts_recording, itr);
 370         bool wrapped;
 371         int err;
 372
 373         pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
 374                   __func__, idx, (size_t)*old, (size_t)*head);
 375
 376         if (idx >= btsr->snapshot_ref_cnt) {
 377                 err = intel_bts_alloc_snapshot_refs(btsr, idx);
 378                 if (err)
 379                         goto out_err;
 380         }
 381
 382         wrapped = btsr->snapshot_refs[idx].wrapped;
 383         if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) {
 384                 btsr->snapshot_refs[idx].wrapped = true;
 385                 wrapped = true;
 386         }
 387
 388         /*
 389          * In full trace mode 'head' continually increases.  However in snapshot
 390          * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
 391          * are adjusted to match the full trace case which expects that 'old' is
 392          * always less than 'head'.
 393          */
 394         if (wrapped) {
 395                 *old = *head;
 396                 *head += mm->len;
 397         } else {
 398                 if (mm->mask)
 399                         *old &= mm->mask;
 400                 else
 401                         *old %= mm->len;
 402                 if (*old > *head)
 403                         *head += mm->len;
 404         }
 405
 406         pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
 407                   __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
 408
 409         return 0;
 410
 411 out_err:
 412         pr_err("%s: failed, error %d\n", __func__, err);
 413         return err;
 414 }
 415
 416 struct auxtrace_record *intel_bts_recording_init(int *err)
 417 {
 418         struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME);
 419         struct intel_bts_recording *btsr;
 420
 421         if (!intel_bts_pmu)
 422                 return NULL;
 423
 424         if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
 425                 *err = -errno;
 426                 return NULL;
 427         }
 428
 429         btsr = zalloc(sizeof(struct intel_bts_recording));
 430         if (!btsr) {
 431                 *err = -ENOMEM;
 432                 return NULL;
 433         }
 434
 435         btsr->intel_bts_pmu = intel_bts_pmu;
 436         btsr->itr.pmu = intel_bts_pmu;
 437         btsr->itr.recording_options = intel_bts_recording_options;
 438         btsr->itr.info_priv_size = intel_bts_info_priv_size;
 439         btsr->itr.info_fill = intel_bts_info_fill;
 440         btsr->itr.free = intel_bts_recording_free;
 441         btsr->itr.snapshot_start = intel_bts_snapshot_start;
 442         btsr->itr.snapshot_finish = intel_bts_snapshot_finish;
 443         btsr->itr.find_snapshot = intel_bts_find_snapshot;
 444         btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options;
 445         btsr->itr.reference = intel_bts_reference;
 446         btsr->itr.read_finish = auxtrace_record__read_finish;
 447         btsr->itr.alignment = sizeof(struct branch);
 448         return &btsr->itr;
 449 }