tools/perf/arch/arm64/util/arm-spe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Arm Statistical Profiling Extensions (SPE) support
   4  * Copyright (c) 2017-2018, Arm Ltd.
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/types.h>
   9 #include <linux/bitops.h>
  10 #include <linux/log2.h>
  11 #include <linux/zalloc.h>
  12 #include <time.h>
  13
  14 #include "../../../util/cpumap.h"
  15 #include "../../../util/event.h"
  16 #include "../../../util/evsel.h"
  17 #include "../../../util/evsel_config.h"
  18 #include "../../../util/evlist.h"
  19 #include "../../../util/session.h"
  20 #include <internal/lib.h> // page_size
  21 #include "../../../util/pmu.h"
  22 #include "../../../util/debug.h"
  23 #include "../../../util/auxtrace.h"
  24 #include "../../../util/record.h"
  25 #include "../../../util/arm-spe.h"
  26 #include <tools/libc_compat.h> // reallocarray
  27
  28 #define KiB(x) ((x) * 1024)
  29 #define MiB(x) ((x) * 1024 * 1024)
  30
  31 struct arm_spe_recording {
  32         struct auxtrace_record          itr;
  33         struct perf_pmu                 *arm_spe_pmu;
  34         struct evlist           *evlist;
  35         int                     wrapped_cnt;
  36         bool                    *wrapped;
  37 };
  38
  39 static void arm_spe_set_timestamp(struct auxtrace_record *itr,
  40                                   struct evsel *evsel)
  41 {
  42         struct arm_spe_recording *ptr;
  43         struct perf_pmu *arm_spe_pmu;
  44         struct evsel_config_term *term = evsel__get_config_term(evsel, CFG_CHG);
  45         u64 user_bits = 0, bit;
  46
  47         ptr = container_of(itr, struct arm_spe_recording, itr);
  48         arm_spe_pmu = ptr->arm_spe_pmu;
  49
  50         if (term)
  51                 user_bits = term->val.cfg_chg;
  52
  53         bit = perf_pmu__format_bits(&arm_spe_pmu->format, "ts_enable");
  54
  55         /* Skip if user has set it */
  56         if (bit & user_bits)
  57                 return;
  58
  59         evsel->core.attr.config |= bit;
  60 }
  61
  62 static size_t
  63 arm_spe_info_priv_size(struct auxtrace_record *itr __maybe_unused,
  64                        struct evlist *evlist __maybe_unused)
  65 {
  66         return ARM_SPE_AUXTRACE_PRIV_SIZE;
  67 }
  68
  69 static int arm_spe_info_fill(struct auxtrace_record *itr,
  70                              struct perf_session *session,
  71                              struct perf_record_auxtrace_info *auxtrace_info,
  72                              size_t priv_size)
  73 {
  74         struct arm_spe_recording *sper =
  75                         container_of(itr, struct arm_spe_recording, itr);
  76         struct perf_pmu *arm_spe_pmu = sper->arm_spe_pmu;
  77
  78         if (priv_size != ARM_SPE_AUXTRACE_PRIV_SIZE)
  79                 return -EINVAL;
  80
  81         if (!session->evlist->core.nr_mmaps)
  82                 return -EINVAL;
  83
  84         auxtrace_info->type = PERF_AUXTRACE_ARM_SPE;
  85         auxtrace_info->priv[ARM_SPE_PMU_TYPE] = arm_spe_pmu->type;
  86
  87         return 0;
  88 }
  89
  90 static void
  91 arm_spe_snapshot_resolve_auxtrace_defaults(struct record_opts *opts,
  92                                            bool privileged)
  93 {
  94         /*
  95          * The default snapshot size is the auxtrace mmap size. If neither auxtrace mmap size nor
  96          * snapshot size is specified, then the default is 4MiB for privileged users, 128KiB for
  97          * unprivileged users.
  98          *
  99          * The default auxtrace mmap size is 4MiB/page_size for privileged users, 128KiB for
 100          * unprivileged users. If an unprivileged user does not specify mmap pages, the mmap pages
 101          * will be reduced from the default 512KiB/page_size to 256KiB/page_size, otherwise the
 102          * user is likely to get an error as they exceed their mlock limmit.
 103          */
 104
 105         /*
 106          * No size were given to '-S' or '-m,', so go with the default
 107          */
 108         if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
 109                 if (privileged) {
 110                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 111                 } else {
 112                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 113                         if (opts->mmap_pages == UINT_MAX)
 114                                 opts->mmap_pages = KiB(256) / page_size;
 115                 }
 116         } else if (!opts->auxtrace_mmap_pages && !privileged && opts->mmap_pages == UINT_MAX) {
 117                 opts->mmap_pages = KiB(256) / page_size;
 118         }
 119
 120         /*
 121          * '-m,xyz' was specified but no snapshot size, so make the snapshot size as big as the
 122          * auxtrace mmap area.
 123          */
 124         if (!opts->auxtrace_snapshot_size)
 125                 opts->auxtrace_snapshot_size = opts->auxtrace_mmap_pages * (size_t)page_size;
 126
 127         /*
 128          * '-Sxyz' was specified but no auxtrace mmap area, so make the auxtrace mmap area big
 129          * enough to fit the requested snapshot size.
 130          */
 131         if (!opts->auxtrace_mmap_pages) {
 132                 size_t sz = opts->auxtrace_snapshot_size;
 133
 134                 sz = round_up(sz, page_size) / page_size;
 135                 opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
 136         }
 137 }
 138
 139 static int arm_spe_recording_options(struct auxtrace_record *itr,
 140                                      struct evlist *evlist,
 141                                      struct record_opts *opts)
 142 {
 143         struct arm_spe_recording *sper =
 144                         container_of(itr, struct arm_spe_recording, itr);
 145         struct perf_pmu *arm_spe_pmu = sper->arm_spe_pmu;
 146         struct evsel *evsel, *arm_spe_evsel = NULL;
 147         struct perf_cpu_map *cpus = evlist->core.user_requested_cpus;
 148         bool privileged = perf_event_paranoid_check(-1);
 149         struct evsel *tracking_evsel;
 150         int err;
 151
 152         sper->evlist = evlist;
 153
 154         evlist__for_each_entry(evlist, evsel) {
 155                 if (evsel->core.attr.type == arm_spe_pmu->type) {
 156                         if (arm_spe_evsel) {
 157                                 pr_err("There may be only one " ARM_SPE_PMU_NAME "x event\n");
 158                                 return -EINVAL;
 159                         }
 160                         evsel->core.attr.freq = 0;
 161                         evsel->core.attr.sample_period = arm_spe_pmu->default_config->sample_period;
 162                         arm_spe_evsel = evsel;
 163                         opts->full_auxtrace = true;
 164                 }
 165         }
 166
 167         if (!opts->full_auxtrace)
 168                 return 0;
 169
 170         /*
 171          * we are in snapshot mode.
 172          */
 173         if (opts->auxtrace_snapshot_mode) {
 174                 /*
 175                  * Command arguments '-Sxyz' and/or '-m,xyz' are missing, so fill those in with
 176                  * default values.
 177                  */
 178                 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages)
 179                         arm_spe_snapshot_resolve_auxtrace_defaults(opts, privileged);
 180
 181                 /*
 182                  * Snapshot size can't be bigger than the auxtrace area.
 183                  */
 184                 if (opts->auxtrace_snapshot_size > opts->auxtrace_mmap_pages * (size_t)page_size) {
 185                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
 186                                opts->auxtrace_snapshot_size,
 187                                opts->auxtrace_mmap_pages * (size_t)page_size);
 188                         return -EINVAL;
 189                 }
 190
 191                 /*
 192                  * Something went wrong somewhere - this shouldn't happen.
 193                  */
 194                 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
 195                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
 196                         return -EINVAL;
 197                 }
 198         }
 199
 200         /* We are in full trace mode but '-m,xyz' wasn't specified */
 201         if (!opts->auxtrace_mmap_pages) {
 202                 if (privileged) {
 203                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 204                 } else {
 205                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 206                         if (opts->mmap_pages == UINT_MAX)
 207                                 opts->mmap_pages = KiB(256) / page_size;
 208                 }
 209         }
 210
 211         /* Validate auxtrace_mmap_pages */
 212         if (opts->auxtrace_mmap_pages) {
 213                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
 214                 size_t min_sz = KiB(8);
 215
 216                 if (sz < min_sz || !is_power_of_2(sz)) {
 217                         pr_err("Invalid mmap size for ARM SPE: must be at least %zuKiB and a power of 2\n",
 218                                min_sz / 1024);
 219                         return -EINVAL;
 220                 }
 221         }
 222
 223         if (opts->auxtrace_snapshot_mode)
 224                 pr_debug2("%sx snapshot size: %zu\n", ARM_SPE_PMU_NAME,
 225                           opts->auxtrace_snapshot_size);
 226
 227         /*
 228          * To obtain the auxtrace buffer file descriptor, the auxtrace event
 229          * must come first.
 230          */
 231         evlist__to_front(evlist, arm_spe_evsel);
 232
 233         /*
 234          * In the case of per-cpu mmaps, sample CPU for AUX event;
 235          * also enable the timestamp tracing for samples correlation.
 236          */
 237         if (!perf_cpu_map__empty(cpus)) {
 238                 evsel__set_sample_bit(arm_spe_evsel, CPU);
 239                 arm_spe_set_timestamp(itr, arm_spe_evsel);
 240         }
 241
 242         /* Add dummy event to keep tracking */
 243         err = parse_events(evlist, "dummy:u", NULL);
 244         if (err)
 245                 return err;
 246
 247         tracking_evsel = evlist__last(evlist);
 248         evlist__set_tracking_event(evlist, tracking_evsel);
 249
 250         tracking_evsel->core.attr.freq = 0;
 251         tracking_evsel->core.attr.sample_period = 1;
 252
 253         /* In per-cpu case, always need the time of mmap events etc */
 254         if (!perf_cpu_map__empty(cpus)) {
 255                 evsel__set_sample_bit(tracking_evsel, TIME);
 256                 evsel__set_sample_bit(tracking_evsel, CPU);
 257
 258                 /* also track task context switch */
 259                 if (!record_opts__no_switch_events(opts))
 260                         tracking_evsel->core.attr.context_switch = 1;
 261         }
 262
 263         return 0;
 264 }
 265
 266 static int arm_spe_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
 267                                          struct record_opts *opts,
 268                                          const char *str)
 269 {
 270         unsigned long long snapshot_size = 0;
 271         char *endptr;
 272
 273         if (str) {
 274                 snapshot_size = strtoull(str, &endptr, 0);
 275                 if (*endptr || snapshot_size > SIZE_MAX)
 276                         return -1;
 277         }
 278
 279         opts->auxtrace_snapshot_mode = true;
 280         opts->auxtrace_snapshot_size = snapshot_size;
 281
 282         return 0;
 283 }
 284
 285 static int arm_spe_snapshot_start(struct auxtrace_record *itr)
 286 {
 287         struct arm_spe_recording *ptr =
 288                         container_of(itr, struct arm_spe_recording, itr);
 289         struct evsel *evsel;
 290
 291         evlist__for_each_entry(ptr->evlist, evsel) {
 292                 if (evsel->core.attr.type == ptr->arm_spe_pmu->type)
 293                         return evsel__disable(evsel);
 294         }
 295         return -EINVAL;
 296 }
 297
 298 static int arm_spe_snapshot_finish(struct auxtrace_record *itr)
 299 {
 300         struct arm_spe_recording *ptr =
 301                         container_of(itr, struct arm_spe_recording, itr);
 302         struct evsel *evsel;
 303
 304         evlist__for_each_entry(ptr->evlist, evsel) {
 305                 if (evsel->core.attr.type == ptr->arm_spe_pmu->type)
 306                         return evsel__enable(evsel);
 307         }
 308         return -EINVAL;
 309 }
 310
 311 static int arm_spe_alloc_wrapped_array(struct arm_spe_recording *ptr, int idx)
 312 {
 313         bool *wrapped;
 314         int cnt = ptr->wrapped_cnt, new_cnt, i;
 315
 316         /*
 317          * No need to allocate, so return early.
 318          */
 319         if (idx < cnt)
 320                 return 0;
 321
 322         /*
 323          * Make ptr->wrapped as big as idx.
 324          */
 325         new_cnt = idx + 1;
 326
 327         /*
 328          * Free'ed in arm_spe_recording_free().
 329          */
 330         wrapped = reallocarray(ptr->wrapped, new_cnt, sizeof(bool));
 331         if (!wrapped)
 332                 return -ENOMEM;
 333
 334         /*
 335          * init new allocated values.
 336          */
 337         for (i = cnt; i < new_cnt; i++)
 338                 wrapped[i] = false;
 339
 340         ptr->wrapped_cnt = new_cnt;
 341         ptr->wrapped = wrapped;
 342
 343         return 0;
 344 }
 345
 346 static bool arm_spe_buffer_has_wrapped(unsigned char *buffer,
 347                                       size_t buffer_size, u64 head)
 348 {
 349         u64 i, watermark;
 350         u64 *buf = (u64 *)buffer;
 351         size_t buf_size = buffer_size;
 352
 353         /*
 354          * Defensively handle the case where head might be continually increasing - if its value is
 355          * equal or greater than the size of the ring buffer, then we can safely determine it has
 356          * wrapped around. Otherwise, continue to detect if head might have wrapped.
 357          */
 358         if (head >= buffer_size)
 359                 return true;
 360
 361         /*
 362          * We want to look the very last 512 byte (chosen arbitrarily) in the ring buffer.
 363          */
 364         watermark = buf_size - 512;
 365
 366         /*
 367          * The value of head is somewhere within the size of the ring buffer. This can be that there
 368          * hasn't been enough data to fill the ring buffer yet or the trace time was so long that
 369          * head has numerically wrapped around.  To find we need to check if we have data at the
 370          * very end of the ring buffer.  We can reliably do this because mmap'ed pages are zeroed
 371          * out and there is a fresh mapping with every new session.
 372          */
 373
 374         /*
 375          * head is less than 512 byte from the end of the ring buffer.
 376          */
 377         if (head > watermark)
 378                 watermark = head;
 379
 380         /*
 381          * Speed things up by using 64 bit transactions (see "u64 *buf" above)
 382          */
 383         watermark /= sizeof(u64);
 384         buf_size /= sizeof(u64);
 385
 386         /*
 387          * If we find trace data at the end of the ring buffer, head has been there and has
 388          * numerically wrapped around at least once.
 389          */
 390         for (i = watermark; i < buf_size; i++)
 391                 if (buf[i])
 392                         return true;
 393
 394         return false;
 395 }
 396
 397 static int arm_spe_find_snapshot(struct auxtrace_record *itr, int idx,
 398                                   struct auxtrace_mmap *mm, unsigned char *data,
 399                                   u64 *head, u64 *old)
 400 {
 401         int err;
 402         bool wrapped;
 403         struct arm_spe_recording *ptr =
 404                         container_of(itr, struct arm_spe_recording, itr);
 405
 406         /*
 407          * Allocate memory to keep track of wrapping if this is the first
 408          * time we deal with this *mm.
 409          */
 410         if (idx >= ptr->wrapped_cnt) {
 411                 err = arm_spe_alloc_wrapped_array(ptr, idx);
 412                 if (err)
 413                         return err;
 414         }
 415
 416         /*
 417          * Check to see if *head has wrapped around.  If it hasn't only the
 418          * amount of data between *head and *old is snapshot'ed to avoid
 419          * bloating the perf.data file with zeros.  But as soon as *head has
 420          * wrapped around the entire size of the AUX ring buffer it taken.
 421          */
 422         wrapped = ptr->wrapped[idx];
 423         if (!wrapped && arm_spe_buffer_has_wrapped(data, mm->len, *head)) {
 424                 wrapped = true;
 425                 ptr->wrapped[idx] = true;
 426         }
 427
 428         pr_debug3("%s: mmap index %d old head %zu new head %zu size %zu\n",
 429                   __func__, idx, (size_t)*old, (size_t)*head, mm->len);
 430
 431         /*
 432          * No wrap has occurred, we can just use *head and *old.
 433          */
 434         if (!wrapped)
 435                 return 0;
 436
 437         /*
 438          * *head has wrapped around - adjust *head and *old to pickup the
 439          * entire content of the AUX buffer.
 440          */
 441         if (*head >= mm->len) {
 442                 *old = *head - mm->len;
 443         } else {
 444                 *head += mm->len;
 445                 *old = *head - mm->len;
 446         }
 447
 448         return 0;
 449 }
 450
 451 static u64 arm_spe_reference(struct auxtrace_record *itr __maybe_unused)
 452 {
 453         struct timespec ts;
 454
 455         clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
 456
 457         return ts.tv_sec ^ ts.tv_nsec;
 458 }
 459
 460 static void arm_spe_recording_free(struct auxtrace_record *itr)
 461 {
 462         struct arm_spe_recording *sper =
 463                         container_of(itr, struct arm_spe_recording, itr);
 464
 465         free(sper->wrapped);
 466         free(sper);
 467 }
 468
 469 struct auxtrace_record *arm_spe_recording_init(int *err,
 470                                                struct perf_pmu *arm_spe_pmu)
 471 {
 472         struct arm_spe_recording *sper;
 473
 474         if (!arm_spe_pmu) {
 475                 *err = -ENODEV;
 476                 return NULL;
 477         }
 478
 479         sper = zalloc(sizeof(struct arm_spe_recording));
 480         if (!sper) {
 481                 *err = -ENOMEM;
 482                 return NULL;
 483         }
 484
 485         sper->arm_spe_pmu = arm_spe_pmu;
 486         sper->itr.pmu = arm_spe_pmu;
 487         sper->itr.snapshot_start = arm_spe_snapshot_start;
 488         sper->itr.snapshot_finish = arm_spe_snapshot_finish;
 489         sper->itr.find_snapshot = arm_spe_find_snapshot;
 490         sper->itr.parse_snapshot_options = arm_spe_parse_snapshot_options;
 491         sper->itr.recording_options = arm_spe_recording_options;
 492         sper->itr.info_priv_size = arm_spe_info_priv_size;
 493         sper->itr.info_fill = arm_spe_info_fill;
 494         sper->itr.free = arm_spe_recording_free;
 495         sper->itr.reference = arm_spe_reference;
 496         sper->itr.read_finish = auxtrace_record__read_finish;
 497         sper->itr.alignment = 0;
 498
 499         *err = 0;
 500         return &sper->itr;
 501 }
 502
 503 struct perf_event_attr
 504 *arm_spe_pmu_default_config(struct perf_pmu *arm_spe_pmu)
 505 {
 506         struct perf_event_attr *attr;
 507
 508         attr = zalloc(sizeof(struct perf_event_attr));
 509         if (!attr) {
 510                 pr_err("arm_spe default config cannot allocate a perf_event_attr\n");
 511                 return NULL;
 512         }
 513
 514         /*
 515          * If kernel driver doesn't advertise a minimum,
 516          * use max allowable by PMSIDR_EL1.INTERVAL
 517          */
 518         if (perf_pmu__scan_file(arm_spe_pmu, "caps/min_interval", "%llu",
 519                                   &attr->sample_period) != 1) {
 520                 pr_debug("arm_spe driver doesn't advertise a min. interval. Using 4096\n");
 521                 attr->sample_period = 4096;
 522         }
 523
 524         arm_spe_pmu->selectable = true;
 525         arm_spe_pmu->is_uncore = false;
 526
 527         return attr;
 528 }