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