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Linux/tools/perf/arch/x86/util/intel-pt.c

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  1 /*
  2  * intel_pt.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 <stdbool.h>
 18 #include <linux/kernel.h>
 19 #include <linux/types.h>
 20 #include <linux/bitops.h>
 21 #include <linux/log2.h>
 22 #include <cpuid.h>
 23 
 24 #include "../../perf.h"
 25 #include "../../util/session.h"
 26 #include "../../util/event.h"
 27 #include "../../util/evlist.h"
 28 #include "../../util/evsel.h"
 29 #include "../../util/cpumap.h"
 30 #include <subcmd/parse-options.h>
 31 #include "../../util/parse-events.h"
 32 #include "../../util/pmu.h"
 33 #include "../../util/debug.h"
 34 #include "../../util/auxtrace.h"
 35 #include "../../util/tsc.h"
 36 #include "../../util/intel-pt.h"
 37 
 38 #define KiB(x) ((x) * 1024)
 39 #define MiB(x) ((x) * 1024 * 1024)
 40 #define KiB_MASK(x) (KiB(x) - 1)
 41 #define MiB_MASK(x) (MiB(x) - 1)
 42 
 43 #define INTEL_PT_PSB_PERIOD_NEAR        256
 44 
 45 struct intel_pt_snapshot_ref {
 46         void *ref_buf;
 47         size_t ref_offset;
 48         bool wrapped;
 49 };
 50 
 51 struct intel_pt_recording {
 52         struct auxtrace_record          itr;
 53         struct perf_pmu                 *intel_pt_pmu;
 54         int                             have_sched_switch;
 55         struct perf_evlist              *evlist;
 56         bool                            snapshot_mode;
 57         bool                            snapshot_init_done;
 58         size_t                          snapshot_size;
 59         size_t                          snapshot_ref_buf_size;
 60         int                             snapshot_ref_cnt;
 61         struct intel_pt_snapshot_ref    *snapshot_refs;
 62         size_t                          priv_size;
 63 };
 64 
 65 static int intel_pt_parse_terms_with_default(struct list_head *formats,
 66                                              const char *str,
 67                                              u64 *config)
 68 {
 69         struct list_head *terms;
 70         struct perf_event_attr attr = { .size = 0, };
 71         int err;
 72 
 73         terms = malloc(sizeof(struct list_head));
 74         if (!terms)
 75                 return -ENOMEM;
 76 
 77         INIT_LIST_HEAD(terms);
 78 
 79         err = parse_events_terms(terms, str);
 80         if (err)
 81                 goto out_free;
 82 
 83         attr.config = *config;
 84         err = perf_pmu__config_terms(formats, &attr, terms, true, NULL);
 85         if (err)
 86                 goto out_free;
 87 
 88         *config = attr.config;
 89 out_free:
 90         parse_events_terms__delete(terms);
 91         return err;
 92 }
 93 
 94 static int intel_pt_parse_terms(struct list_head *formats, const char *str,
 95                                 u64 *config)
 96 {
 97         *config = 0;
 98         return intel_pt_parse_terms_with_default(formats, str, config);
 99 }
100 
101 static u64 intel_pt_masked_bits(u64 mask, u64 bits)
102 {
103         const u64 top_bit = 1ULL << 63;
104         u64 res = 0;
105         int i;
106 
107         for (i = 0; i < 64; i++) {
108                 if (mask & top_bit) {
109                         res <<= 1;
110                         if (bits & top_bit)
111                                 res |= 1;
112                 }
113                 mask <<= 1;
114                 bits <<= 1;
115         }
116 
117         return res;
118 }
119 
120 static int intel_pt_read_config(struct perf_pmu *intel_pt_pmu, const char *str,
121                                 struct perf_evlist *evlist, u64 *res)
122 {
123         struct perf_evsel *evsel;
124         u64 mask;
125 
126         *res = 0;
127 
128         mask = perf_pmu__format_bits(&intel_pt_pmu->format, str);
129         if (!mask)
130                 return -EINVAL;
131 
132         evlist__for_each_entry(evlist, evsel) {
133                 if (evsel->attr.type == intel_pt_pmu->type) {
134                         *res = intel_pt_masked_bits(mask, evsel->attr.config);
135                         return 0;
136                 }
137         }
138 
139         return -EINVAL;
140 }
141 
142 static size_t intel_pt_psb_period(struct perf_pmu *intel_pt_pmu,
143                                   struct perf_evlist *evlist)
144 {
145         u64 val;
146         int err, topa_multiple_entries;
147         size_t psb_period;
148 
149         if (perf_pmu__scan_file(intel_pt_pmu, "caps/topa_multiple_entries",
150                                 "%d", &topa_multiple_entries) != 1)
151                 topa_multiple_entries = 0;
152 
153         /*
154          * Use caps/topa_multiple_entries to indicate early hardware that had
155          * extra frequent PSBs.
156          */
157         if (!topa_multiple_entries) {
158                 psb_period = 256;
159                 goto out;
160         }
161 
162         err = intel_pt_read_config(intel_pt_pmu, "psb_period", evlist, &val);
163         if (err)
164                 val = 0;
165 
166         psb_period = 1 << (val + 11);
167 out:
168         pr_debug2("%s psb_period %zu\n", intel_pt_pmu->name, psb_period);
169         return psb_period;
170 }
171 
172 static int intel_pt_pick_bit(int bits, int target)
173 {
174         int pos, pick = -1;
175 
176         for (pos = 0; bits; bits >>= 1, pos++) {
177                 if (bits & 1) {
178                         if (pos <= target || pick < 0)
179                                 pick = pos;
180                         if (pos >= target)
181                                 break;
182                 }
183         }
184 
185         return pick;
186 }
187 
188 static u64 intel_pt_default_config(struct perf_pmu *intel_pt_pmu)
189 {
190         char buf[256];
191         int mtc, mtc_periods = 0, mtc_period;
192         int psb_cyc, psb_periods, psb_period;
193         int pos = 0;
194         u64 config;
195         char c;
196 
197         pos += scnprintf(buf + pos, sizeof(buf) - pos, "tsc");
198 
199         if (perf_pmu__scan_file(intel_pt_pmu, "caps/mtc", "%d",
200                                 &mtc) != 1)
201                 mtc = 1;
202 
203         if (mtc) {
204                 if (perf_pmu__scan_file(intel_pt_pmu, "caps/mtc_periods", "%x",
205                                         &mtc_periods) != 1)
206                         mtc_periods = 0;
207                 if (mtc_periods) {
208                         mtc_period = intel_pt_pick_bit(mtc_periods, 3);
209                         pos += scnprintf(buf + pos, sizeof(buf) - pos,
210                                          ",mtc,mtc_period=%d", mtc_period);
211                 }
212         }
213 
214         if (perf_pmu__scan_file(intel_pt_pmu, "caps/psb_cyc", "%d",
215                                 &psb_cyc) != 1)
216                 psb_cyc = 1;
217 
218         if (psb_cyc && mtc_periods) {
219                 if (perf_pmu__scan_file(intel_pt_pmu, "caps/psb_periods", "%x",
220                                         &psb_periods) != 1)
221                         psb_periods = 0;
222                 if (psb_periods) {
223                         psb_period = intel_pt_pick_bit(psb_periods, 3);
224                         pos += scnprintf(buf + pos, sizeof(buf) - pos,
225                                          ",psb_period=%d", psb_period);
226                 }
227         }
228 
229         if (perf_pmu__scan_file(intel_pt_pmu, "format/pt", "%c", &c) == 1 &&
230             perf_pmu__scan_file(intel_pt_pmu, "format/branch", "%c", &c) == 1)
231                 pos += scnprintf(buf + pos, sizeof(buf) - pos, ",pt,branch");
232 
233         pr_debug2("%s default config: %s\n", intel_pt_pmu->name, buf);
234 
235         intel_pt_parse_terms(&intel_pt_pmu->format, buf, &config);
236 
237         return config;
238 }
239 
240 static int intel_pt_parse_snapshot_options(struct auxtrace_record *itr,
241                                            struct record_opts *opts,
242                                            const char *str)
243 {
244         struct intel_pt_recording *ptr =
245                         container_of(itr, struct intel_pt_recording, itr);
246         unsigned long long snapshot_size = 0;
247         char *endptr;
248 
249         if (str) {
250                 snapshot_size = strtoull(str, &endptr, 0);
251                 if (*endptr || snapshot_size > SIZE_MAX)
252                         return -1;
253         }
254 
255         opts->auxtrace_snapshot_mode = true;
256         opts->auxtrace_snapshot_size = snapshot_size;
257 
258         ptr->snapshot_size = snapshot_size;
259 
260         return 0;
261 }
262 
263 struct perf_event_attr *
264 intel_pt_pmu_default_config(struct perf_pmu *intel_pt_pmu)
265 {
266         struct perf_event_attr *attr;
267 
268         attr = zalloc(sizeof(struct perf_event_attr));
269         if (!attr)
270                 return NULL;
271 
272         attr->config = intel_pt_default_config(intel_pt_pmu);
273 
274         intel_pt_pmu->selectable = true;
275 
276         return attr;
277 }
278 
279 static const char *intel_pt_find_filter(struct perf_evlist *evlist,
280                                         struct perf_pmu *intel_pt_pmu)
281 {
282         struct perf_evsel *evsel;
283 
284         evlist__for_each_entry(evlist, evsel) {
285                 if (evsel->attr.type == intel_pt_pmu->type)
286                         return evsel->filter;
287         }
288 
289         return NULL;
290 }
291 
292 static size_t intel_pt_filter_bytes(const char *filter)
293 {
294         size_t len = filter ? strlen(filter) : 0;
295 
296         return len ? roundup(len + 1, 8) : 0;
297 }
298 
299 static size_t
300 intel_pt_info_priv_size(struct auxtrace_record *itr, struct perf_evlist *evlist)
301 {
302         struct intel_pt_recording *ptr =
303                         container_of(itr, struct intel_pt_recording, itr);
304         const char *filter = intel_pt_find_filter(evlist, ptr->intel_pt_pmu);
305 
306         ptr->priv_size = (INTEL_PT_AUXTRACE_PRIV_MAX * sizeof(u64)) +
307                          intel_pt_filter_bytes(filter);
308 
309         return ptr->priv_size;
310 }
311 
312 static void intel_pt_tsc_ctc_ratio(u32 *n, u32 *d)
313 {
314         unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0;
315 
316         __get_cpuid(0x15, &eax, &ebx, &ecx, &edx);
317         *n = ebx;
318         *d = eax;
319 }
320 
321 static int intel_pt_info_fill(struct auxtrace_record *itr,
322                               struct perf_session *session,
323                               struct auxtrace_info_event *auxtrace_info,
324                               size_t priv_size)
325 {
326         struct intel_pt_recording *ptr =
327                         container_of(itr, struct intel_pt_recording, itr);
328         struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
329         struct perf_event_mmap_page *pc;
330         struct perf_tsc_conversion tc = { .time_mult = 0, };
331         bool cap_user_time_zero = false, per_cpu_mmaps;
332         u64 tsc_bit, mtc_bit, mtc_freq_bits, cyc_bit, noretcomp_bit;
333         u32 tsc_ctc_ratio_n, tsc_ctc_ratio_d;
334         unsigned long max_non_turbo_ratio;
335         size_t filter_str_len;
336         const char *filter;
337         u64 *info;
338         int err;
339 
340         if (priv_size != ptr->priv_size)
341                 return -EINVAL;
342 
343         intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
344         intel_pt_parse_terms(&intel_pt_pmu->format, "noretcomp",
345                              &noretcomp_bit);
346         intel_pt_parse_terms(&intel_pt_pmu->format, "mtc", &mtc_bit);
347         mtc_freq_bits = perf_pmu__format_bits(&intel_pt_pmu->format,
348                                               "mtc_period");
349         intel_pt_parse_terms(&intel_pt_pmu->format, "cyc", &cyc_bit);
350 
351         intel_pt_tsc_ctc_ratio(&tsc_ctc_ratio_n, &tsc_ctc_ratio_d);
352 
353         if (perf_pmu__scan_file(intel_pt_pmu, "max_nonturbo_ratio",
354                                 "%lu", &max_non_turbo_ratio) != 1)
355                 max_non_turbo_ratio = 0;
356 
357         filter = intel_pt_find_filter(session->evlist, ptr->intel_pt_pmu);
358         filter_str_len = filter ? strlen(filter) : 0;
359 
360         if (!session->evlist->nr_mmaps)
361                 return -EINVAL;
362 
363         pc = session->evlist->mmap[0].base;
364         if (pc) {
365                 err = perf_read_tsc_conversion(pc, &tc);
366                 if (err) {
367                         if (err != -EOPNOTSUPP)
368                                 return err;
369                 } else {
370                         cap_user_time_zero = tc.time_mult != 0;
371                 }
372                 if (!cap_user_time_zero)
373                         ui__warning("Intel Processor Trace: TSC not available\n");
374         }
375 
376         per_cpu_mmaps = !cpu_map__empty(session->evlist->cpus);
377 
378         auxtrace_info->type = PERF_AUXTRACE_INTEL_PT;
379         auxtrace_info->priv[INTEL_PT_PMU_TYPE] = intel_pt_pmu->type;
380         auxtrace_info->priv[INTEL_PT_TIME_SHIFT] = tc.time_shift;
381         auxtrace_info->priv[INTEL_PT_TIME_MULT] = tc.time_mult;
382         auxtrace_info->priv[INTEL_PT_TIME_ZERO] = tc.time_zero;
383         auxtrace_info->priv[INTEL_PT_CAP_USER_TIME_ZERO] = cap_user_time_zero;
384         auxtrace_info->priv[INTEL_PT_TSC_BIT] = tsc_bit;
385         auxtrace_info->priv[INTEL_PT_NORETCOMP_BIT] = noretcomp_bit;
386         auxtrace_info->priv[INTEL_PT_HAVE_SCHED_SWITCH] = ptr->have_sched_switch;
387         auxtrace_info->priv[INTEL_PT_SNAPSHOT_MODE] = ptr->snapshot_mode;
388         auxtrace_info->priv[INTEL_PT_PER_CPU_MMAPS] = per_cpu_mmaps;
389         auxtrace_info->priv[INTEL_PT_MTC_BIT] = mtc_bit;
390         auxtrace_info->priv[INTEL_PT_MTC_FREQ_BITS] = mtc_freq_bits;
391         auxtrace_info->priv[INTEL_PT_TSC_CTC_N] = tsc_ctc_ratio_n;
392         auxtrace_info->priv[INTEL_PT_TSC_CTC_D] = tsc_ctc_ratio_d;
393         auxtrace_info->priv[INTEL_PT_CYC_BIT] = cyc_bit;
394         auxtrace_info->priv[INTEL_PT_MAX_NONTURBO_RATIO] = max_non_turbo_ratio;
395         auxtrace_info->priv[INTEL_PT_FILTER_STR_LEN] = filter_str_len;
396 
397         info = &auxtrace_info->priv[INTEL_PT_FILTER_STR_LEN] + 1;
398 
399         if (filter_str_len) {
400                 size_t len = intel_pt_filter_bytes(filter);
401 
402                 strncpy((char *)info, filter, len);
403                 info += len >> 3;
404         }
405 
406         return 0;
407 }
408 
409 static int intel_pt_track_switches(struct perf_evlist *evlist)
410 {
411         const char *sched_switch = "sched:sched_switch";
412         struct perf_evsel *evsel;
413         int err;
414 
415         if (!perf_evlist__can_select_event(evlist, sched_switch))
416                 return -EPERM;
417 
418         err = parse_events(evlist, sched_switch, NULL);
419         if (err) {
420                 pr_debug2("%s: failed to parse %s, error %d\n",
421                           __func__, sched_switch, err);
422                 return err;
423         }
424 
425         evsel = perf_evlist__last(evlist);
426 
427         perf_evsel__set_sample_bit(evsel, CPU);
428         perf_evsel__set_sample_bit(evsel, TIME);
429 
430         evsel->system_wide = true;
431         evsel->no_aux_samples = true;
432         evsel->immediate = true;
433 
434         return 0;
435 }
436 
437 static void intel_pt_valid_str(char *str, size_t len, u64 valid)
438 {
439         unsigned int val, last = 0, state = 1;
440         int p = 0;
441 
442         str[0] = '\0';
443 
444         for (val = 0; val <= 64; val++, valid >>= 1) {
445                 if (valid & 1) {
446                         last = val;
447                         switch (state) {
448                         case 0:
449                                 p += scnprintf(str + p, len - p, ",");
450                                 /* Fall through */
451                         case 1:
452                                 p += scnprintf(str + p, len - p, "%u", val);
453                                 state = 2;
454                                 break;
455                         case 2:
456                                 state = 3;
457                                 break;
458                         case 3:
459                                 state = 4;
460                                 break;
461                         default:
462                                 break;
463                         }
464                 } else {
465                         switch (state) {
466                         case 3:
467                                 p += scnprintf(str + p, len - p, ",%u", last);
468                                 state = 0;
469                                 break;
470                         case 4:
471                                 p += scnprintf(str + p, len - p, "-%u", last);
472                                 state = 0;
473                                 break;
474                         default:
475                                 break;
476                         }
477                         if (state != 1)
478                                 state = 0;
479                 }
480         }
481 }
482 
483 static int intel_pt_val_config_term(struct perf_pmu *intel_pt_pmu,
484                                     const char *caps, const char *name,
485                                     const char *supported, u64 config)
486 {
487         char valid_str[256];
488         unsigned int shift;
489         unsigned long long valid;
490         u64 bits;
491         int ok;
492 
493         if (perf_pmu__scan_file(intel_pt_pmu, caps, "%llx", &valid) != 1)
494                 valid = 0;
495 
496         if (supported &&
497             perf_pmu__scan_file(intel_pt_pmu, supported, "%d", &ok) == 1 && !ok)
498                 valid = 0;
499 
500         valid |= 1;
501 
502         bits = perf_pmu__format_bits(&intel_pt_pmu->format, name);
503 
504         config &= bits;
505 
506         for (shift = 0; bits && !(bits & 1); shift++)
507                 bits >>= 1;
508 
509         config >>= shift;
510 
511         if (config > 63)
512                 goto out_err;
513 
514         if (valid & (1 << config))
515                 return 0;
516 out_err:
517         intel_pt_valid_str(valid_str, sizeof(valid_str), valid);
518         pr_err("Invalid %s for %s. Valid values are: %s\n",
519                name, INTEL_PT_PMU_NAME, valid_str);
520         return -EINVAL;
521 }
522 
523 static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu,
524                                     struct perf_evsel *evsel)
525 {
526         int err;
527 
528         if (!evsel)
529                 return 0;
530 
531         err = intel_pt_val_config_term(intel_pt_pmu, "caps/cycle_thresholds",
532                                        "cyc_thresh", "caps/psb_cyc",
533                                        evsel->attr.config);
534         if (err)
535                 return err;
536 
537         err = intel_pt_val_config_term(intel_pt_pmu, "caps/mtc_periods",
538                                        "mtc_period", "caps/mtc",
539                                        evsel->attr.config);
540         if (err)
541                 return err;
542 
543         return intel_pt_val_config_term(intel_pt_pmu, "caps/psb_periods",
544                                         "psb_period", "caps/psb_cyc",
545                                         evsel->attr.config);
546 }
547 
548 static int intel_pt_recording_options(struct auxtrace_record *itr,
549                                       struct perf_evlist *evlist,
550                                       struct record_opts *opts)
551 {
552         struct intel_pt_recording *ptr =
553                         container_of(itr, struct intel_pt_recording, itr);
554         struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
555         bool have_timing_info, need_immediate = false;
556         struct perf_evsel *evsel, *intel_pt_evsel = NULL;
557         const struct cpu_map *cpus = evlist->cpus;
558         bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
559         u64 tsc_bit;
560         int err;
561 
562         ptr->evlist = evlist;
563         ptr->snapshot_mode = opts->auxtrace_snapshot_mode;
564 
565         evlist__for_each_entry(evlist, evsel) {
566                 if (evsel->attr.type == intel_pt_pmu->type) {
567                         if (intel_pt_evsel) {
568                                 pr_err("There may be only one " INTEL_PT_PMU_NAME " event\n");
569                                 return -EINVAL;
570                         }
571                         evsel->attr.freq = 0;
572                         evsel->attr.sample_period = 1;
573                         intel_pt_evsel = evsel;
574                         opts->full_auxtrace = true;
575                 }
576         }
577 
578         if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
579                 pr_err("Snapshot mode (-S option) requires " INTEL_PT_PMU_NAME " PMU event (-e " INTEL_PT_PMU_NAME ")\n");
580                 return -EINVAL;
581         }
582 
583         if (opts->use_clockid) {
584                 pr_err("Cannot use clockid (-k option) with " INTEL_PT_PMU_NAME "\n");
585                 return -EINVAL;
586         }
587 
588         if (!opts->full_auxtrace)
589                 return 0;
590 
591         err = intel_pt_validate_config(intel_pt_pmu, intel_pt_evsel);
592         if (err)
593                 return err;
594 
595         /* Set default sizes for snapshot mode */
596         if (opts->auxtrace_snapshot_mode) {
597                 size_t psb_period = intel_pt_psb_period(intel_pt_pmu, evlist);
598 
599                 if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
600                         if (privileged) {
601                                 opts->auxtrace_mmap_pages = MiB(4) / page_size;
602                         } else {
603                                 opts->auxtrace_mmap_pages = KiB(128) / page_size;
604                                 if (opts->mmap_pages == UINT_MAX)
605                                         opts->mmap_pages = KiB(256) / page_size;
606                         }
607                 } else if (!opts->auxtrace_mmap_pages && !privileged &&
608                            opts->mmap_pages == UINT_MAX) {
609                         opts->mmap_pages = KiB(256) / page_size;
610                 }
611                 if (!opts->auxtrace_snapshot_size)
612                         opts->auxtrace_snapshot_size =
613                                 opts->auxtrace_mmap_pages * (size_t)page_size;
614                 if (!opts->auxtrace_mmap_pages) {
615                         size_t sz = opts->auxtrace_snapshot_size;
616 
617                         sz = round_up(sz, page_size) / page_size;
618                         opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
619                 }
620                 if (opts->auxtrace_snapshot_size >
621                                 opts->auxtrace_mmap_pages * (size_t)page_size) {
622                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
623                                opts->auxtrace_snapshot_size,
624                                opts->auxtrace_mmap_pages * (size_t)page_size);
625                         return -EINVAL;
626                 }
627                 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
628                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
629                         return -EINVAL;
630                 }
631                 pr_debug2("Intel PT snapshot size: %zu\n",
632                           opts->auxtrace_snapshot_size);
633                 if (psb_period &&
634                     opts->auxtrace_snapshot_size <= psb_period +
635                                                   INTEL_PT_PSB_PERIOD_NEAR)
636                         ui__warning("Intel PT snapshot size (%zu) may be too small for PSB period (%zu)\n",
637                                     opts->auxtrace_snapshot_size, psb_period);
638         }
639 
640         /* Set default sizes for full trace mode */
641         if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
642                 if (privileged) {
643                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
644                 } else {
645                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
646                         if (opts->mmap_pages == UINT_MAX)
647                                 opts->mmap_pages = KiB(256) / page_size;
648                 }
649         }
650 
651         /* Validate auxtrace_mmap_pages */
652         if (opts->auxtrace_mmap_pages) {
653                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
654                 size_t min_sz;
655 
656                 if (opts->auxtrace_snapshot_mode)
657                         min_sz = KiB(4);
658                 else
659                         min_sz = KiB(8);
660 
661                 if (sz < min_sz || !is_power_of_2(sz)) {
662                         pr_err("Invalid mmap size for Intel Processor Trace: must be at least %zuKiB and a power of 2\n",
663                                min_sz / 1024);
664                         return -EINVAL;
665                 }
666         }
667 
668         intel_pt_parse_terms(&intel_pt_pmu->format, "tsc", &tsc_bit);
669 
670         if (opts->full_auxtrace && (intel_pt_evsel->attr.config & tsc_bit))
671                 have_timing_info = true;
672         else
673                 have_timing_info = false;
674 
675         /*
676          * Per-cpu recording needs sched_switch events to distinguish different
677          * threads.
678          */
679         if (have_timing_info && !cpu_map__empty(cpus)) {
680                 if (perf_can_record_switch_events()) {
681                         bool cpu_wide = !target__none(&opts->target) &&
682                                         !target__has_task(&opts->target);
683 
684                         if (!cpu_wide && perf_can_record_cpu_wide()) {
685                                 struct perf_evsel *switch_evsel;
686 
687                                 err = parse_events(evlist, "dummy:u", NULL);
688                                 if (err)
689                                         return err;
690 
691                                 switch_evsel = perf_evlist__last(evlist);
692 
693                                 switch_evsel->attr.freq = 0;
694                                 switch_evsel->attr.sample_period = 1;
695                                 switch_evsel->attr.context_switch = 1;
696 
697                                 switch_evsel->system_wide = true;
698                                 switch_evsel->no_aux_samples = true;
699                                 switch_evsel->immediate = true;
700 
701                                 perf_evsel__set_sample_bit(switch_evsel, TID);
702                                 perf_evsel__set_sample_bit(switch_evsel, TIME);
703                                 perf_evsel__set_sample_bit(switch_evsel, CPU);
704 
705                                 opts->record_switch_events = false;
706                                 ptr->have_sched_switch = 3;
707                         } else {
708                                 opts->record_switch_events = true;
709                                 need_immediate = true;
710                                 if (cpu_wide)
711                                         ptr->have_sched_switch = 3;
712                                 else
713                                         ptr->have_sched_switch = 2;
714                         }
715                 } else {
716                         err = intel_pt_track_switches(evlist);
717                         if (err == -EPERM)
718                                 pr_debug2("Unable to select sched:sched_switch\n");
719                         else if (err)
720                                 return err;
721                         else
722                                 ptr->have_sched_switch = 1;
723                 }
724         }
725 
726         if (intel_pt_evsel) {
727                 /*
728                  * To obtain the auxtrace buffer file descriptor, the auxtrace
729                  * event must come first.
730                  */
731                 perf_evlist__to_front(evlist, intel_pt_evsel);
732                 /*
733                  * In the case of per-cpu mmaps, we need the CPU on the
734                  * AUX event.
735                  */
736                 if (!cpu_map__empty(cpus))
737                         perf_evsel__set_sample_bit(intel_pt_evsel, CPU);
738         }
739 
740         /* Add dummy event to keep tracking */
741         if (opts->full_auxtrace) {
742                 struct perf_evsel *tracking_evsel;
743 
744                 err = parse_events(evlist, "dummy:u", NULL);
745                 if (err)
746                         return err;
747 
748                 tracking_evsel = perf_evlist__last(evlist);
749 
750                 perf_evlist__set_tracking_event(evlist, tracking_evsel);
751 
752                 tracking_evsel->attr.freq = 0;
753                 tracking_evsel->attr.sample_period = 1;
754 
755                 if (need_immediate)
756                         tracking_evsel->immediate = true;
757 
758                 /* In per-cpu case, always need the time of mmap events etc */
759                 if (!cpu_map__empty(cpus)) {
760                         perf_evsel__set_sample_bit(tracking_evsel, TIME);
761                         /* And the CPU for switch events */
762                         perf_evsel__set_sample_bit(tracking_evsel, CPU);
763                 }
764         }
765 
766         /*
767          * Warn the user when we do not have enough information to decode i.e.
768          * per-cpu with no sched_switch (except workload-only).
769          */
770         if (!ptr->have_sched_switch && !cpu_map__empty(cpus) &&
771             !target__none(&opts->target))
772                 ui__warning("Intel Processor Trace decoding will not be possible except for kernel tracing!\n");
773 
774         return 0;
775 }
776 
777 static int intel_pt_snapshot_start(struct auxtrace_record *itr)
778 {
779         struct intel_pt_recording *ptr =
780                         container_of(itr, struct intel_pt_recording, itr);
781         struct perf_evsel *evsel;
782 
783         evlist__for_each_entry(ptr->evlist, evsel) {
784                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
785                         return perf_evsel__disable(evsel);
786         }
787         return -EINVAL;
788 }
789 
790 static int intel_pt_snapshot_finish(struct auxtrace_record *itr)
791 {
792         struct intel_pt_recording *ptr =
793                         container_of(itr, struct intel_pt_recording, itr);
794         struct perf_evsel *evsel;
795 
796         evlist__for_each_entry(ptr->evlist, evsel) {
797                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
798                         return perf_evsel__enable(evsel);
799         }
800         return -EINVAL;
801 }
802 
803 static int intel_pt_alloc_snapshot_refs(struct intel_pt_recording *ptr, int idx)
804 {
805         const size_t sz = sizeof(struct intel_pt_snapshot_ref);
806         int cnt = ptr->snapshot_ref_cnt, new_cnt = cnt * 2;
807         struct intel_pt_snapshot_ref *refs;
808 
809         if (!new_cnt)
810                 new_cnt = 16;
811 
812         while (new_cnt <= idx)
813                 new_cnt *= 2;
814 
815         refs = calloc(new_cnt, sz);
816         if (!refs)
817                 return -ENOMEM;
818 
819         memcpy(refs, ptr->snapshot_refs, cnt * sz);
820 
821         ptr->snapshot_refs = refs;
822         ptr->snapshot_ref_cnt = new_cnt;
823 
824         return 0;
825 }
826 
827 static void intel_pt_free_snapshot_refs(struct intel_pt_recording *ptr)
828 {
829         int i;
830 
831         for (i = 0; i < ptr->snapshot_ref_cnt; i++)
832                 zfree(&ptr->snapshot_refs[i].ref_buf);
833         zfree(&ptr->snapshot_refs);
834 }
835 
836 static void intel_pt_recording_free(struct auxtrace_record *itr)
837 {
838         struct intel_pt_recording *ptr =
839                         container_of(itr, struct intel_pt_recording, itr);
840 
841         intel_pt_free_snapshot_refs(ptr);
842         free(ptr);
843 }
844 
845 static int intel_pt_alloc_snapshot_ref(struct intel_pt_recording *ptr, int idx,
846                                        size_t snapshot_buf_size)
847 {
848         size_t ref_buf_size = ptr->snapshot_ref_buf_size;
849         void *ref_buf;
850 
851         ref_buf = zalloc(ref_buf_size);
852         if (!ref_buf)
853                 return -ENOMEM;
854 
855         ptr->snapshot_refs[idx].ref_buf = ref_buf;
856         ptr->snapshot_refs[idx].ref_offset = snapshot_buf_size - ref_buf_size;
857 
858         return 0;
859 }
860 
861 static size_t intel_pt_snapshot_ref_buf_size(struct intel_pt_recording *ptr,
862                                              size_t snapshot_buf_size)
863 {
864         const size_t max_size = 256 * 1024;
865         size_t buf_size = 0, psb_period;
866 
867         if (ptr->snapshot_size <= 64 * 1024)
868                 return 0;
869 
870         psb_period = intel_pt_psb_period(ptr->intel_pt_pmu, ptr->evlist);
871         if (psb_period)
872                 buf_size = psb_period * 2;
873 
874         if (!buf_size || buf_size > max_size)
875                 buf_size = max_size;
876 
877         if (buf_size >= snapshot_buf_size)
878                 return 0;
879 
880         if (buf_size >= ptr->snapshot_size / 2)
881                 return 0;
882 
883         return buf_size;
884 }
885 
886 static int intel_pt_snapshot_init(struct intel_pt_recording *ptr,
887                                   size_t snapshot_buf_size)
888 {
889         if (ptr->snapshot_init_done)
890                 return 0;
891 
892         ptr->snapshot_init_done = true;
893 
894         ptr->snapshot_ref_buf_size = intel_pt_snapshot_ref_buf_size(ptr,
895                                                         snapshot_buf_size);
896 
897         return 0;
898 }
899 
900 /**
901  * intel_pt_compare_buffers - compare bytes in a buffer to a circular buffer.
902  * @buf1: first buffer
903  * @compare_size: number of bytes to compare
904  * @buf2: second buffer (a circular buffer)
905  * @offs2: offset in second buffer
906  * @buf2_size: size of second buffer
907  *
908  * The comparison allows for the possibility that the bytes to compare in the
909  * circular buffer are not contiguous.  It is assumed that @compare_size <=
910  * @buf2_size.  This function returns %false if the bytes are identical, %true
911  * otherwise.
912  */
913 static bool intel_pt_compare_buffers(void *buf1, size_t compare_size,
914                                      void *buf2, size_t offs2, size_t buf2_size)
915 {
916         size_t end2 = offs2 + compare_size, part_size;
917 
918         if (end2 <= buf2_size)
919                 return memcmp(buf1, buf2 + offs2, compare_size);
920 
921         part_size = end2 - buf2_size;
922         if (memcmp(buf1, buf2 + offs2, part_size))
923                 return true;
924 
925         compare_size -= part_size;
926 
927         return memcmp(buf1 + part_size, buf2, compare_size);
928 }
929 
930 static bool intel_pt_compare_ref(void *ref_buf, size_t ref_offset,
931                                  size_t ref_size, size_t buf_size,
932                                  void *data, size_t head)
933 {
934         size_t ref_end = ref_offset + ref_size;
935 
936         if (ref_end > buf_size) {
937                 if (head > ref_offset || head < ref_end - buf_size)
938                         return true;
939         } else if (head > ref_offset && head < ref_end) {
940                 return true;
941         }
942 
943         return intel_pt_compare_buffers(ref_buf, ref_size, data, ref_offset,
944                                         buf_size);
945 }
946 
947 static void intel_pt_copy_ref(void *ref_buf, size_t ref_size, size_t buf_size,
948                               void *data, size_t head)
949 {
950         if (head >= ref_size) {
951                 memcpy(ref_buf, data + head - ref_size, ref_size);
952         } else {
953                 memcpy(ref_buf, data, head);
954                 ref_size -= head;
955                 memcpy(ref_buf + head, data + buf_size - ref_size, ref_size);
956         }
957 }
958 
959 static bool intel_pt_wrapped(struct intel_pt_recording *ptr, int idx,
960                              struct auxtrace_mmap *mm, unsigned char *data,
961                              u64 head)
962 {
963         struct intel_pt_snapshot_ref *ref = &ptr->snapshot_refs[idx];
964         bool wrapped;
965 
966         wrapped = intel_pt_compare_ref(ref->ref_buf, ref->ref_offset,
967                                        ptr->snapshot_ref_buf_size, mm->len,
968                                        data, head);
969 
970         intel_pt_copy_ref(ref->ref_buf, ptr->snapshot_ref_buf_size, mm->len,
971                           data, head);
972 
973         return wrapped;
974 }
975 
976 static bool intel_pt_first_wrap(u64 *data, size_t buf_size)
977 {
978         int i, a, b;
979 
980         b = buf_size >> 3;
981         a = b - 512;
982         if (a < 0)
983                 a = 0;
984 
985         for (i = a; i < b; i++) {
986                 if (data[i])
987                         return true;
988         }
989 
990         return false;
991 }
992 
993 static int intel_pt_find_snapshot(struct auxtrace_record *itr, int idx,
994                                   struct auxtrace_mmap *mm, unsigned char *data,
995                                   u64 *head, u64 *old)
996 {
997         struct intel_pt_recording *ptr =
998                         container_of(itr, struct intel_pt_recording, itr);
999         bool wrapped;
1000         int err;
1001 
1002         pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
1003                   __func__, idx, (size_t)*old, (size_t)*head);
1004 
1005         err = intel_pt_snapshot_init(ptr, mm->len);
1006         if (err)
1007                 goto out_err;
1008 
1009         if (idx >= ptr->snapshot_ref_cnt) {
1010                 err = intel_pt_alloc_snapshot_refs(ptr, idx);
1011                 if (err)
1012                         goto out_err;
1013         }
1014 
1015         if (ptr->snapshot_ref_buf_size) {
1016                 if (!ptr->snapshot_refs[idx].ref_buf) {
1017                         err = intel_pt_alloc_snapshot_ref(ptr, idx, mm->len);
1018                         if (err)
1019                                 goto out_err;
1020                 }
1021                 wrapped = intel_pt_wrapped(ptr, idx, mm, data, *head);
1022         } else {
1023                 wrapped = ptr->snapshot_refs[idx].wrapped;
1024                 if (!wrapped && intel_pt_first_wrap((u64 *)data, mm->len)) {
1025                         ptr->snapshot_refs[idx].wrapped = true;
1026                         wrapped = true;
1027                 }
1028         }
1029 
1030         /*
1031          * In full trace mode 'head' continually increases.  However in snapshot
1032          * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
1033          * are adjusted to match the full trace case which expects that 'old' is
1034          * always less than 'head'.
1035          */
1036         if (wrapped) {
1037                 *old = *head;
1038                 *head += mm->len;
1039         } else {
1040                 if (mm->mask)
1041                         *old &= mm->mask;
1042                 else
1043                         *old %= mm->len;
1044                 if (*old > *head)
1045                         *head += mm->len;
1046         }
1047 
1048         pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
1049                   __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
1050 
1051         return 0;
1052 
1053 out_err:
1054         pr_err("%s: failed, error %d\n", __func__, err);
1055         return err;
1056 }
1057 
1058 static u64 intel_pt_reference(struct auxtrace_record *itr __maybe_unused)
1059 {
1060         return rdtsc();
1061 }
1062 
1063 static int intel_pt_read_finish(struct auxtrace_record *itr, int idx)
1064 {
1065         struct intel_pt_recording *ptr =
1066                         container_of(itr, struct intel_pt_recording, itr);
1067         struct perf_evsel *evsel;
1068 
1069         evlist__for_each_entry(ptr->evlist, evsel) {
1070                 if (evsel->attr.type == ptr->intel_pt_pmu->type)
1071                         return perf_evlist__enable_event_idx(ptr->evlist, evsel,
1072                                                              idx);
1073         }
1074         return -EINVAL;
1075 }
1076 
1077 struct auxtrace_record *intel_pt_recording_init(int *err)
1078 {
1079         struct perf_pmu *intel_pt_pmu = perf_pmu__find(INTEL_PT_PMU_NAME);
1080         struct intel_pt_recording *ptr;
1081 
1082         if (!intel_pt_pmu)
1083                 return NULL;
1084 
1085         if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
1086                 *err = -errno;
1087                 return NULL;
1088         }
1089 
1090         ptr = zalloc(sizeof(struct intel_pt_recording));
1091         if (!ptr) {
1092                 *err = -ENOMEM;
1093                 return NULL;
1094         }
1095 
1096         ptr->intel_pt_pmu = intel_pt_pmu;
1097         ptr->itr.recording_options = intel_pt_recording_options;
1098         ptr->itr.info_priv_size = intel_pt_info_priv_size;
1099         ptr->itr.info_fill = intel_pt_info_fill;
1100         ptr->itr.free = intel_pt_recording_free;
1101         ptr->itr.snapshot_start = intel_pt_snapshot_start;
1102         ptr->itr.snapshot_finish = intel_pt_snapshot_finish;
1103         ptr->itr.find_snapshot = intel_pt_find_snapshot;
1104         ptr->itr.parse_snapshot_options = intel_pt_parse_snapshot_options;
1105         ptr->itr.reference = intel_pt_reference;
1106         ptr->itr.read_finish = intel_pt_read_finish;
1107         return &ptr->itr;
1108 }
1109 

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