1 /* 2 * intel-bts.c: Intel Processor Trace support 3 * Copyright (c) 2013-2015, Intel Corporation. 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms and conditions of the GNU General Public License, 7 * version 2, as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 12 * more details. 13 * 14 */ 15 16 #include <errno.h> 17 #include <linux/kernel.h> 18 #include <linux/types.h> 19 #include <linux/bitops.h> 20 #include <linux/log2.h> 21 22 #include "../../util/cpumap.h" 23 #include "../../util/evsel.h" 24 #include "../../util/evlist.h" 25 #include "../../util/session.h" 26 #include "../../util/util.h" 27 #include "../../util/pmu.h" 28 #include "../../util/debug.h" 29 #include "../../util/tsc.h" 30 #include "../../util/auxtrace.h" 31 #include "../../util/intel-bts.h" 32 33 #define KiB(x) ((x) * 1024) 34 #define MiB(x) ((x) * 1024 * 1024) 35 #define KiB_MASK(x) (KiB(x) - 1) 36 #define MiB_MASK(x) (MiB(x) - 1) 37 38 struct intel_bts_snapshot_ref { 39 void *ref_buf; 40 size_t ref_offset; 41 bool wrapped; 42 }; 43 44 struct intel_bts_recording { 45 struct auxtrace_record itr; 46 struct perf_pmu *intel_bts_pmu; 47 struct perf_evlist *evlist; 48 bool snapshot_mode; 49 size_t snapshot_size; 50 int snapshot_ref_cnt; 51 struct intel_bts_snapshot_ref *snapshot_refs; 52 }; 53 54 struct branch { 55 u64 from; 56 u64 to; 57 u64 misc; 58 }; 59 60 static size_t 61 intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused, 62 struct perf_evlist *evlist __maybe_unused) 63 { 64 return INTEL_BTS_AUXTRACE_PRIV_SIZE; 65 } 66 67 static int intel_bts_info_fill(struct auxtrace_record *itr, 68 struct perf_session *session, 69 struct auxtrace_info_event *auxtrace_info, 70 size_t priv_size) 71 { 72 struct intel_bts_recording *btsr = 73 container_of(itr, struct intel_bts_recording, itr); 74 struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu; 75 struct perf_event_mmap_page *pc; 76 struct perf_tsc_conversion tc = { .time_mult = 0, }; 77 bool cap_user_time_zero = false; 78 int err; 79 80 if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE) 81 return -EINVAL; 82 83 if (!session->evlist->nr_mmaps) 84 return -EINVAL; 85 86 pc = session->evlist->mmap[0].base; 87 if (pc) { 88 err = perf_read_tsc_conversion(pc, &tc); 89 if (err) { 90 if (err != -EOPNOTSUPP) 91 return err; 92 } else { 93 cap_user_time_zero = tc.time_mult != 0; 94 } 95 if (!cap_user_time_zero) 96 ui__warning("Intel BTS: TSC not available\n"); 97 } 98 99 auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS; 100 auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type; 101 auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift; 102 auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult; 103 auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero; 104 auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero; 105 auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode; 106 107 return 0; 108 } 109 110 static int intel_bts_recording_options(struct auxtrace_record *itr, 111 struct perf_evlist *evlist, 112 struct record_opts *opts) 113 { 114 struct intel_bts_recording *btsr = 115 container_of(itr, struct intel_bts_recording, itr); 116 struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu; 117 struct perf_evsel *evsel, *intel_bts_evsel = NULL; 118 const struct cpu_map *cpus = evlist->cpus; 119 bool privileged = geteuid() == 0 || perf_event_paranoid() < 0; 120 121 btsr->evlist = evlist; 122 btsr->snapshot_mode = opts->auxtrace_snapshot_mode; 123 124 evlist__for_each_entry(evlist, evsel) { 125 if (evsel->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->attr.freq = 0; 131 evsel->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 && !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 perf_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 (!cpu_map__empty(cpus)) 227 perf_evsel__set_sample_bit(intel_bts_evsel, CPU); 228 } 229 230 /* Add dummy event to keep tracking */ 231 if (opts->full_auxtrace) { 232 struct perf_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 = perf_evlist__last(evlist); 240 241 perf_evlist__set_tracking_event(evlist, tracking_evsel); 242 243 tracking_evsel->attr.freq = 0; 244 tracking_evsel->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 perf_evsel *evsel; 326 327 evlist__for_each_entry(btsr->evlist, evsel) { 328 if (evsel->attr.type == btsr->intel_bts_pmu->type) 329 return perf_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 perf_evsel *evsel; 339 340 evlist__for_each_entry(btsr->evlist, evsel) { 341 if (evsel->attr.type == btsr->intel_bts_pmu->type) 342 return perf_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 static int intel_bts_read_finish(struct auxtrace_record *itr, int idx) 417 { 418 struct intel_bts_recording *btsr = 419 container_of(itr, struct intel_bts_recording, itr); 420 struct perf_evsel *evsel; 421 422 evlist__for_each_entry(btsr->evlist, evsel) { 423 if (evsel->attr.type == btsr->intel_bts_pmu->type) 424 return perf_evlist__enable_event_idx(btsr->evlist, 425 evsel, idx); 426 } 427 return -EINVAL; 428 } 429 430 struct auxtrace_record *intel_bts_recording_init(int *err) 431 { 432 struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME); 433 struct intel_bts_recording *btsr; 434 435 if (!intel_bts_pmu) 436 return NULL; 437 438 if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) { 439 *err = -errno; 440 return NULL; 441 } 442 443 btsr = zalloc(sizeof(struct intel_bts_recording)); 444 if (!btsr) { 445 *err = -ENOMEM; 446 return NULL; 447 } 448 449 btsr->intel_bts_pmu = intel_bts_pmu; 450 btsr->itr.recording_options = intel_bts_recording_options; 451 btsr->itr.info_priv_size = intel_bts_info_priv_size; 452 btsr->itr.info_fill = intel_bts_info_fill; 453 btsr->itr.free = intel_bts_recording_free; 454 btsr->itr.snapshot_start = intel_bts_snapshot_start; 455 btsr->itr.snapshot_finish = intel_bts_snapshot_finish; 456 btsr->itr.find_snapshot = intel_bts_find_snapshot; 457 btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options; 458 btsr->itr.reference = intel_bts_reference; 459 btsr->itr.read_finish = intel_bts_read_finish; 460 btsr->itr.alignment = sizeof(struct branch); 461 return &btsr->itr; 462 } 463