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 13 #include "../../util/cpumap.h" 14 #include "../../util/evsel.h" 15 #include "../../util/evlist.h" 16 #include "../../util/session.h" 17 #include "../../util/util.h" 18 #include "../../util/pmu.h" 19 #include "../../util/debug.h" 20 #include "../../util/tsc.h" 21 #include "../../util/auxtrace.h" 22 #include "../../util/intel-bts.h" 23 24 #define KiB(x) ((x) * 1024) 25 #define MiB(x) ((x) * 1024 * 1024) 26 #define KiB_MASK(x) (KiB(x) - 1) 27 #define MiB_MASK(x) (MiB(x) - 1) 28 29 struct intel_bts_snapshot_ref { 30 void *ref_buf; 31 size_t ref_offset; 32 bool wrapped; 33 }; 34 35 struct intel_bts_recording { 36 struct auxtrace_record itr; 37 struct perf_pmu *intel_bts_pmu; 38 struct perf_evlist *evlist; 39 bool snapshot_mode; 40 size_t snapshot_size; 41 int snapshot_ref_cnt; 42 struct intel_bts_snapshot_ref *snapshot_refs; 43 }; 44 45 struct branch { 46 u64 from; 47 u64 to; 48 u64 misc; 49 }; 50 51 static size_t 52 intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused, 53 struct perf_evlist *evlist __maybe_unused) 54 { 55 return INTEL_BTS_AUXTRACE_PRIV_SIZE; 56 } 57 58 static int intel_bts_info_fill(struct auxtrace_record *itr, 59 struct perf_session *session, 60 struct auxtrace_info_event *auxtrace_info, 61 size_t priv_size) 62 { 63 struct intel_bts_recording *btsr = 64 container_of(itr, struct intel_bts_recording, itr); 65 struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu; 66 struct perf_event_mmap_page *pc; 67 struct perf_tsc_conversion tc = { .time_mult = 0, }; 68 bool cap_user_time_zero = false; 69 int err; 70 71 if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE) 72 return -EINVAL; 73 74 if (!session->evlist->nr_mmaps) 75 return -EINVAL; 76 77 pc = session->evlist->mmap[0].base; 78 if (pc) { 79 err = perf_read_tsc_conversion(pc, &tc); 80 if (err) { 81 if (err != -EOPNOTSUPP) 82 return err; 83 } else { 84 cap_user_time_zero = tc.time_mult != 0; 85 } 86 if (!cap_user_time_zero) 87 ui__warning("Intel BTS: TSC not available\n"); 88 } 89 90 auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS; 91 auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type; 92 auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift; 93 auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult; 94 auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero; 95 auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero; 96 auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode; 97 98 return 0; 99 } 100 101 static int intel_bts_recording_options(struct auxtrace_record *itr, 102 struct perf_evlist *evlist, 103 struct record_opts *opts) 104 { 105 struct intel_bts_recording *btsr = 106 container_of(itr, struct intel_bts_recording, itr); 107 struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu; 108 struct perf_evsel *evsel, *intel_bts_evsel = NULL; 109 const struct cpu_map *cpus = evlist->cpus; 110 bool privileged = geteuid() == 0 || perf_event_paranoid() < 0; 111 112 btsr->evlist = evlist; 113 btsr->snapshot_mode = opts->auxtrace_snapshot_mode; 114 115 evlist__for_each_entry(evlist, evsel) { 116 if (evsel->attr.type == intel_bts_pmu->type) { 117 if (intel_bts_evsel) { 118 pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n"); 119 return -EINVAL; 120 } 121 evsel->attr.freq = 0; 122 evsel->attr.sample_period = 1; 123 intel_bts_evsel = evsel; 124 opts->full_auxtrace = true; 125 } 126 } 127 128 if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) { 129 pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n"); 130 return -EINVAL; 131 } 132 133 if (!opts->full_auxtrace) 134 return 0; 135 136 if (opts->full_auxtrace && !cpu_map__empty(cpus)) { 137 pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n"); 138 return -EINVAL; 139 } 140 141 /* Set default sizes for snapshot mode */ 142 if (opts->auxtrace_snapshot_mode) { 143 if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) { 144 if (privileged) { 145 opts->auxtrace_mmap_pages = MiB(4) / page_size; 146 } else { 147 opts->auxtrace_mmap_pages = KiB(128) / page_size; 148 if (opts->mmap_pages == UINT_MAX) 149 opts->mmap_pages = KiB(256) / page_size; 150 } 151 } else if (!opts->auxtrace_mmap_pages && !privileged && 152 opts->mmap_pages == UINT_MAX) { 153 opts->mmap_pages = KiB(256) / page_size; 154 } 155 if (!opts->auxtrace_snapshot_size) 156 opts->auxtrace_snapshot_size = 157 opts->auxtrace_mmap_pages * (size_t)page_size; 158 if (!opts->auxtrace_mmap_pages) { 159 size_t sz = opts->auxtrace_snapshot_size; 160 161 sz = round_up(sz, page_size) / page_size; 162 opts->auxtrace_mmap_pages = roundup_pow_of_two(sz); 163 } 164 if (opts->auxtrace_snapshot_size > 165 opts->auxtrace_mmap_pages * (size_t)page_size) { 166 pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n", 167 opts->auxtrace_snapshot_size, 168 opts->auxtrace_mmap_pages * (size_t)page_size); 169 return -EINVAL; 170 } 171 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) { 172 pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n"); 173 return -EINVAL; 174 } 175 pr_debug2("Intel BTS snapshot size: %zu\n", 176 opts->auxtrace_snapshot_size); 177 } 178 179 /* Set default sizes for full trace mode */ 180 if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) { 181 if (privileged) { 182 opts->auxtrace_mmap_pages = MiB(4) / page_size; 183 } else { 184 opts->auxtrace_mmap_pages = KiB(128) / page_size; 185 if (opts->mmap_pages == UINT_MAX) 186 opts->mmap_pages = KiB(256) / page_size; 187 } 188 } 189 190 /* Validate auxtrace_mmap_pages */ 191 if (opts->auxtrace_mmap_pages) { 192 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size; 193 size_t min_sz; 194 195 if (opts->auxtrace_snapshot_mode) 196 min_sz = KiB(4); 197 else 198 min_sz = KiB(8); 199 200 if (sz < min_sz || !is_power_of_2(sz)) { 201 pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n", 202 min_sz / 1024); 203 return -EINVAL; 204 } 205 } 206 207 if (intel_bts_evsel) { 208 /* 209 * To obtain the auxtrace buffer file descriptor, the auxtrace event 210 * must come first. 211 */ 212 perf_evlist__to_front(evlist, intel_bts_evsel); 213 /* 214 * In the case of per-cpu mmaps, we need the CPU on the 215 * AUX event. 216 */ 217 if (!cpu_map__empty(cpus)) 218 perf_evsel__set_sample_bit(intel_bts_evsel, CPU); 219 } 220 221 /* Add dummy event to keep tracking */ 222 if (opts->full_auxtrace) { 223 struct perf_evsel *tracking_evsel; 224 int err; 225 226 err = parse_events(evlist, "dummy:u", NULL); 227 if (err) 228 return err; 229 230 tracking_evsel = perf_evlist__last(evlist); 231 232 perf_evlist__set_tracking_event(evlist, tracking_evsel); 233 234 tracking_evsel->attr.freq = 0; 235 tracking_evsel->attr.sample_period = 1; 236 } 237 238 return 0; 239 } 240 241 static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr, 242 struct record_opts *opts, 243 const char *str) 244 { 245 struct intel_bts_recording *btsr = 246 container_of(itr, struct intel_bts_recording, itr); 247 unsigned long long snapshot_size = 0; 248 char *endptr; 249 250 if (str) { 251 snapshot_size = strtoull(str, &endptr, 0); 252 if (*endptr || snapshot_size > SIZE_MAX) 253 return -1; 254 } 255 256 opts->auxtrace_snapshot_mode = true; 257 opts->auxtrace_snapshot_size = snapshot_size; 258 259 btsr->snapshot_size = snapshot_size; 260 261 return 0; 262 } 263 264 static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused) 265 { 266 return rdtsc(); 267 } 268 269 static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr, 270 int idx) 271 { 272 const size_t sz = sizeof(struct intel_bts_snapshot_ref); 273 int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2; 274 struct intel_bts_snapshot_ref *refs; 275 276 if (!new_cnt) 277 new_cnt = 16; 278 279 while (new_cnt <= idx) 280 new_cnt *= 2; 281 282 refs = calloc(new_cnt, sz); 283 if (!refs) 284 return -ENOMEM; 285 286 memcpy(refs, btsr->snapshot_refs, cnt * sz); 287 288 btsr->snapshot_refs = refs; 289 btsr->snapshot_ref_cnt = new_cnt; 290 291 return 0; 292 } 293 294 static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr) 295 { 296 int i; 297 298 for (i = 0; i < btsr->snapshot_ref_cnt; i++) 299 zfree(&btsr->snapshot_refs[i].ref_buf); 300 zfree(&btsr->snapshot_refs); 301 } 302 303 static void intel_bts_recording_free(struct auxtrace_record *itr) 304 { 305 struct intel_bts_recording *btsr = 306 container_of(itr, struct intel_bts_recording, itr); 307 308 intel_bts_free_snapshot_refs(btsr); 309 free(btsr); 310 } 311 312 static int intel_bts_snapshot_start(struct auxtrace_record *itr) 313 { 314 struct intel_bts_recording *btsr = 315 container_of(itr, struct intel_bts_recording, itr); 316 struct perf_evsel *evsel; 317 318 evlist__for_each_entry(btsr->evlist, evsel) { 319 if (evsel->attr.type == btsr->intel_bts_pmu->type) 320 return perf_evsel__disable(evsel); 321 } 322 return -EINVAL; 323 } 324 325 static int intel_bts_snapshot_finish(struct auxtrace_record *itr) 326 { 327 struct intel_bts_recording *btsr = 328 container_of(itr, struct intel_bts_recording, itr); 329 struct perf_evsel *evsel; 330 331 evlist__for_each_entry(btsr->evlist, evsel) { 332 if (evsel->attr.type == btsr->intel_bts_pmu->type) 333 return perf_evsel__enable(evsel); 334 } 335 return -EINVAL; 336 } 337 338 static bool intel_bts_first_wrap(u64 *data, size_t buf_size) 339 { 340 int i, a, b; 341 342 b = buf_size >> 3; 343 a = b - 512; 344 if (a < 0) 345 a = 0; 346 347 for (i = a; i < b; i++) { 348 if (data[i]) 349 return true; 350 } 351 352 return false; 353 } 354 355 static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx, 356 struct auxtrace_mmap *mm, unsigned char *data, 357 u64 *head, u64 *old) 358 { 359 struct intel_bts_recording *btsr = 360 container_of(itr, struct intel_bts_recording, itr); 361 bool wrapped; 362 int err; 363 364 pr_debug3("%s: mmap index %d old head %zu new head %zu\n", 365 __func__, idx, (size_t)*old, (size_t)*head); 366 367 if (idx >= btsr->snapshot_ref_cnt) { 368 err = intel_bts_alloc_snapshot_refs(btsr, idx); 369 if (err) 370 goto out_err; 371 } 372 373 wrapped = btsr->snapshot_refs[idx].wrapped; 374 if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) { 375 btsr->snapshot_refs[idx].wrapped = true; 376 wrapped = true; 377 } 378 379 /* 380 * In full trace mode 'head' continually increases. However in snapshot 381 * mode 'head' is an offset within the buffer. Here 'old' and 'head' 382 * are adjusted to match the full trace case which expects that 'old' is 383 * always less than 'head'. 384 */ 385 if (wrapped) { 386 *old = *head; 387 *head += mm->len; 388 } else { 389 if (mm->mask) 390 *old &= mm->mask; 391 else 392 *old %= mm->len; 393 if (*old > *head) 394 *head += mm->len; 395 } 396 397 pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n", 398 __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head); 399 400 return 0; 401 402 out_err: 403 pr_err("%s: failed, error %d\n", __func__, err); 404 return err; 405 } 406 407 static int intel_bts_read_finish(struct auxtrace_record *itr, int idx) 408 { 409 struct intel_bts_recording *btsr = 410 container_of(itr, struct intel_bts_recording, itr); 411 struct perf_evsel *evsel; 412 413 evlist__for_each_entry(btsr->evlist, evsel) { 414 if (evsel->attr.type == btsr->intel_bts_pmu->type) 415 return perf_evlist__enable_event_idx(btsr->evlist, 416 evsel, idx); 417 } 418 return -EINVAL; 419 } 420 421 struct auxtrace_record *intel_bts_recording_init(int *err) 422 { 423 struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME); 424 struct intel_bts_recording *btsr; 425 426 if (!intel_bts_pmu) 427 return NULL; 428 429 if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) { 430 *err = -errno; 431 return NULL; 432 } 433 434 btsr = zalloc(sizeof(struct intel_bts_recording)); 435 if (!btsr) { 436 *err = -ENOMEM; 437 return NULL; 438 } 439 440 btsr->intel_bts_pmu = intel_bts_pmu; 441 btsr->itr.recording_options = intel_bts_recording_options; 442 btsr->itr.info_priv_size = intel_bts_info_priv_size; 443 btsr->itr.info_fill = intel_bts_info_fill; 444 btsr->itr.free = intel_bts_recording_free; 445 btsr->itr.snapshot_start = intel_bts_snapshot_start; 446 btsr->itr.snapshot_finish = intel_bts_snapshot_finish; 447 btsr->itr.find_snapshot = intel_bts_find_snapshot; 448 btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options; 449 btsr->itr.reference = intel_bts_reference; 450 btsr->itr.read_finish = intel_bts_read_finish; 451 btsr->itr.alignment = sizeof(struct branch); 452 return &btsr->itr; 453 } 454