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

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