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/pmus.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.user_requested_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                         evsel->needs_auxtrace_mmap = true;
 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 && !perf_cpu_map__is_any_cpu_or_is_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                 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 (!perf_cpu_map__is_any_cpu_or_is_empty(cpus))
 228                         evsel__set_sample_bit(intel_bts_evsel, CPU);
 229         }
 230
 231         /* Add dummy event to keep tracking */
 232         if (opts->full_auxtrace) {
 233                 struct evsel *tracking_evsel;
 234                 int err;
 235
 236                 err = parse_event(evlist, "dummy:u");
 237                 if (err)
 238                         return err;
 239
 240                 tracking_evsel = evlist__last(evlist);
 241
 242                 evlist__set_tracking_event(evlist, tracking_evsel);
 243
 244                 tracking_evsel->core.attr.freq = 0;
 245                 tracking_evsel->core.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 evsel *evsel;
 327
 328         evlist__for_each_entry(btsr->evlist, evsel) {
 329                 if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
 330                         return evsel__disable(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 evsel *evsel;
 340
 341         evlist__for_each_entry(btsr->evlist, evsel) {
 342                 if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
 343                         return evsel__enable(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 struct auxtrace_record *intel_bts_recording_init(int *err)
 418 {
 419         struct perf_pmu *intel_bts_pmu = perf_pmus__find(INTEL_BTS_PMU_NAME);
 420         struct intel_bts_recording *btsr;
 421
 422         if (!intel_bts_pmu)
 423                 return NULL;
 424
 425         if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
 426                 *err = -errno;
 427                 return NULL;
 428         }
 429
 430         btsr = zalloc(sizeof(struct intel_bts_recording));
 431         if (!btsr) {
 432                 *err = -ENOMEM;
 433                 return NULL;
 434         }
 435
 436         btsr->intel_bts_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 }