1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * intel-bts.c: Intel Processor Trace support
4 * Copyright (c) 2013-2015, Intel Corporation.
5 */
6
7#include <errno.h>
8#include <linux/kernel.h>
9#include <linux/types.h>
10#include <linux/bitops.h>
11#include <linux/log2.h>
12#include <linux/zalloc.h>
13
14#include "../../../util/cpumap.h"
15#include "../../../util/event.h"
16#include "../../../util/evsel.h"
17#include "../../../util/evlist.h"
18#include "../../../util/mmap.h"
19#include "../../../util/session.h"
20#include "../../../util/pmus.h"
21#include "../../../util/debug.h"
22#include "../../../util/record.h"
23#include "../../../util/tsc.h"
24#include "../../../util/auxtrace.h"
25#include "../../../util/intel-bts.h"
26#include <internal/lib.h> // page_size
27
28#define KiB(x) ((x) * 1024)
29#define MiB(x) ((x) * 1024 * 1024)
30#define KiB_MASK(x) (KiB(x) - 1)
31#define MiB_MASK(x) (MiB(x) - 1)
32
33struct intel_bts_snapshot_ref {
34 void *ref_buf;
35 size_t ref_offset;
36 bool wrapped;
37};
38
39struct intel_bts_recording {
40 struct auxtrace_record itr;
41 struct perf_pmu *intel_bts_pmu;
42 struct evlist *evlist;
43 bool snapshot_mode;
44 size_t snapshot_size;
45 int snapshot_ref_cnt;
46 struct intel_bts_snapshot_ref *snapshot_refs;
47};
48
49struct branch {
50 u64 from;
51 u64 to;
52 u64 misc;
53};
54
55static size_t
56intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused,
57 struct evlist *evlist __maybe_unused)
58{
59 return INTEL_BTS_AUXTRACE_PRIV_SIZE;
60}
61
62static int intel_bts_info_fill(struct auxtrace_record *itr,
63 struct perf_session *session,
64 struct perf_record_auxtrace_info *auxtrace_info,
65 size_t priv_size)
66{
67 struct intel_bts_recording *btsr =
68 container_of(itr, struct intel_bts_recording, itr);
69 struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
70 struct perf_event_mmap_page *pc;
71 struct perf_tsc_conversion tc = { .time_mult = 0, };
72 bool cap_user_time_zero = false;
73 int err;
74
75 if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE)
76 return -EINVAL;
77
78 if (!session->evlist->core.nr_mmaps)
79 return -EINVAL;
80
81 pc = session->evlist->mmap[0].core.base;
82 if (pc) {
83 err = perf_read_tsc_conversion(pc, tc: &tc);
84 if (err) {
85 if (err != -EOPNOTSUPP)
86 return err;
87 } else {
88 cap_user_time_zero = tc.time_mult != 0;
89 }
90 if (!cap_user_time_zero)
91 ui__warning(format: "Intel BTS: TSC not available\n");
92 }
93
94 auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS;
95 auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type;
96 auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift;
97 auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult;
98 auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero;
99 auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero;
100 auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode;
101
102 return 0;
103}
104
105static int intel_bts_recording_options(struct auxtrace_record *itr,
106 struct evlist *evlist,
107 struct record_opts *opts)
108{
109 struct intel_bts_recording *btsr =
110 container_of(itr, struct intel_bts_recording, itr);
111 struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
112 struct evsel *evsel, *intel_bts_evsel = NULL;
113 const struct perf_cpu_map *cpus = evlist->core.user_requested_cpus;
114 bool privileged = perf_event_paranoid_check(max_level: -1);
115
116 if (opts->auxtrace_sample_mode) {
117 pr_err("Intel BTS does not support AUX area sampling\n");
118 return -EINVAL;
119 }
120
121 btsr->evlist = evlist;
122 btsr->snapshot_mode = opts->auxtrace_snapshot_mode;
123
124 evlist__for_each_entry(evlist, evsel) {
125 if (evsel->core.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->core.attr.freq = 0;
131 evsel->core.attr.sample_period = 1;
132 evsel->needs_auxtrace_mmap = true;
133 intel_bts_evsel = evsel;
134 opts->full_auxtrace = true;
135 }
136 }
137
138 if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
139 pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
140 return -EINVAL;
141 }
142
143 if (!opts->full_auxtrace)
144 return 0;
145
146 if (opts->full_auxtrace && !perf_cpu_map__is_any_cpu_or_is_empty(cpus)) {
147 pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
148 return -EINVAL;
149 }
150
151 /* Set default sizes for snapshot mode */
152 if (opts->auxtrace_snapshot_mode) {
153 if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
154 if (privileged) {
155 opts->auxtrace_mmap_pages = MiB(4) / page_size;
156 } else {
157 opts->auxtrace_mmap_pages = KiB(128) / page_size;
158 if (opts->mmap_pages == UINT_MAX)
159 opts->mmap_pages = KiB(256) / page_size;
160 }
161 } else if (!opts->auxtrace_mmap_pages && !privileged &&
162 opts->mmap_pages == UINT_MAX) {
163 opts->mmap_pages = KiB(256) / page_size;
164 }
165 if (!opts->auxtrace_snapshot_size)
166 opts->auxtrace_snapshot_size =
167 opts->auxtrace_mmap_pages * (size_t)page_size;
168 if (!opts->auxtrace_mmap_pages) {
169 size_t sz = opts->auxtrace_snapshot_size;
170
171 sz = round_up(sz, page_size) / page_size;
172 opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
173 }
174 if (opts->auxtrace_snapshot_size >
175 opts->auxtrace_mmap_pages * (size_t)page_size) {
176 pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
177 opts->auxtrace_snapshot_size,
178 opts->auxtrace_mmap_pages * (size_t)page_size);
179 return -EINVAL;
180 }
181 if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
182 pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
183 return -EINVAL;
184 }
185 pr_debug2("Intel BTS snapshot size: %zu\n",
186 opts->auxtrace_snapshot_size);
187 }
188
189 /* Set default sizes for full trace mode */
190 if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
191 if (privileged) {
192 opts->auxtrace_mmap_pages = MiB(4) / page_size;
193 } else {
194 opts->auxtrace_mmap_pages = KiB(128) / page_size;
195 if (opts->mmap_pages == UINT_MAX)
196 opts->mmap_pages = KiB(256) / page_size;
197 }
198 }
199
200 /* Validate auxtrace_mmap_pages */
201 if (opts->auxtrace_mmap_pages) {
202 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
203 size_t min_sz;
204
205 if (opts->auxtrace_snapshot_mode)
206 min_sz = KiB(4);
207 else
208 min_sz = KiB(8);
209
210 if (sz < min_sz || !is_power_of_2(n: sz)) {
211 pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
212 min_sz / 1024);
213 return -EINVAL;
214 }
215 }
216
217 if (intel_bts_evsel) {
218 /*
219 * To obtain the auxtrace buffer file descriptor, the auxtrace event
220 * must come first.
221 */
222 evlist__to_front(evlist, move_evsel: intel_bts_evsel);
223 /*
224 * In the case of per-cpu mmaps, we need the CPU on the
225 * AUX event.
226 */
227 if (!perf_cpu_map__is_any_cpu_or_is_empty(cpus))
228 evsel__set_sample_bit(intel_bts_evsel, CPU);
229 }
230
231 /* Add dummy event to keep tracking */
232 if (opts->full_auxtrace) {
233 struct evsel *tracking_evsel;
234 int err;
235
236 err = parse_event(evlist, str: "dummy:u");
237 if (err)
238 return err;
239
240 tracking_evsel = evlist__last(evlist);
241
242 evlist__set_tracking_event(evlist, tracking_evsel);
243
244 tracking_evsel->core.attr.freq = 0;
245 tracking_evsel->core.attr.sample_period = 1;
246 }
247
248 return 0;
249}
250
251static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
252 struct record_opts *opts,
253 const char *str)
254{
255 struct intel_bts_recording *btsr =
256 container_of(itr, struct intel_bts_recording, itr);
257 unsigned long long snapshot_size = 0;
258 char *endptr;
259
260 if (str) {
261 snapshot_size = strtoull(str, &endptr, 0);
262 if (*endptr || snapshot_size > SIZE_MAX)
263 return -1;
264 }
265
266 opts->auxtrace_snapshot_mode = true;
267 opts->auxtrace_snapshot_size = snapshot_size;
268
269 btsr->snapshot_size = snapshot_size;
270
271 return 0;
272}
273
274static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
275{
276 return rdtsc();
277}
278
279static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
280 int idx)
281{
282 const size_t sz = sizeof(struct intel_bts_snapshot_ref);
283 int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
284 struct intel_bts_snapshot_ref *refs;
285
286 if (!new_cnt)
287 new_cnt = 16;
288
289 while (new_cnt <= idx)
290 new_cnt *= 2;
291
292 refs = calloc(new_cnt, sz);
293 if (!refs)
294 return -ENOMEM;
295
296 memcpy(refs, btsr->snapshot_refs, cnt * sz);
297
298 btsr->snapshot_refs = refs;
299 btsr->snapshot_ref_cnt = new_cnt;
300
301 return 0;
302}
303
304static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
305{
306 int i;
307
308 for (i = 0; i < btsr->snapshot_ref_cnt; i++)
309 zfree(&btsr->snapshot_refs[i].ref_buf);
310 zfree(&btsr->snapshot_refs);
311}
312
313static void intel_bts_recording_free(struct auxtrace_record *itr)
314{
315 struct intel_bts_recording *btsr =
316 container_of(itr, struct intel_bts_recording, itr);
317
318 intel_bts_free_snapshot_refs(btsr);
319 free(btsr);
320}
321
322static int intel_bts_snapshot_start(struct auxtrace_record *itr)
323{
324 struct intel_bts_recording *btsr =
325 container_of(itr, struct intel_bts_recording, itr);
326 struct evsel *evsel;
327
328 evlist__for_each_entry(btsr->evlist, evsel) {
329 if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
330 return evsel__disable(evsel);
331 }
332 return -EINVAL;
333}
334
335static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
336{
337 struct intel_bts_recording *btsr =
338 container_of(itr, struct intel_bts_recording, itr);
339 struct evsel *evsel;
340
341 evlist__for_each_entry(btsr->evlist, evsel) {
342 if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
343 return evsel__enable(evsel);
344 }
345 return -EINVAL;
346}
347
348static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
349{
350 int i, a, b;
351
352 b = buf_size >> 3;
353 a = b - 512;
354 if (a < 0)
355 a = 0;
356
357 for (i = a; i < b; i++) {
358 if (data[i])
359 return true;
360 }
361
362 return false;
363}
364
365static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
366 struct auxtrace_mmap *mm, unsigned char *data,
367 u64 *head, u64 *old)
368{
369 struct intel_bts_recording *btsr =
370 container_of(itr, struct intel_bts_recording, itr);
371 bool wrapped;
372 int err;
373
374 pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
375 __func__, idx, (size_t)*old, (size_t)*head);
376
377 if (idx >= btsr->snapshot_ref_cnt) {
378 err = intel_bts_alloc_snapshot_refs(btsr, idx);
379 if (err)
380 goto out_err;
381 }
382
383 wrapped = btsr->snapshot_refs[idx].wrapped;
384 if (!wrapped && intel_bts_first_wrap(data: (u64 *)data, buf_size: mm->len)) {
385 btsr->snapshot_refs[idx].wrapped = true;
386 wrapped = true;
387 }
388
389 /*
390 * In full trace mode 'head' continually increases. However in snapshot
391 * mode 'head' is an offset within the buffer. Here 'old' and 'head'
392 * are adjusted to match the full trace case which expects that 'old' is
393 * always less than 'head'.
394 */
395 if (wrapped) {
396 *old = *head;
397 *head += mm->len;
398 } else {
399 if (mm->mask)
400 *old &= mm->mask;
401 else
402 *old %= mm->len;
403 if (*old > *head)
404 *head += mm->len;
405 }
406
407 pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
408 __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
409
410 return 0;
411
412out_err:
413 pr_err("%s: failed, error %d\n", __func__, err);
414 return err;
415}
416
417struct auxtrace_record *intel_bts_recording_init(int *err)
418{
419 struct perf_pmu *intel_bts_pmu = perf_pmus__find(INTEL_BTS_PMU_NAME);
420 struct intel_bts_recording *btsr;
421
422 if (!intel_bts_pmu)
423 return NULL;
424
425 if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
426 *err = -errno;
427 return NULL;
428 }
429
430 btsr = zalloc(sizeof(struct intel_bts_recording));
431 if (!btsr) {
432 *err = -ENOMEM;
433 return NULL;
434 }
435
436 btsr->intel_bts_pmu = intel_bts_pmu;
437 btsr->itr.recording_options = intel_bts_recording_options;
438 btsr->itr.info_priv_size = intel_bts_info_priv_size;
439 btsr->itr.info_fill = intel_bts_info_fill;
440 btsr->itr.free = intel_bts_recording_free;
441 btsr->itr.snapshot_start = intel_bts_snapshot_start;
442 btsr->itr.snapshot_finish = intel_bts_snapshot_finish;
443 btsr->itr.find_snapshot = intel_bts_find_snapshot;
444 btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options;
445 btsr->itr.reference = intel_bts_reference;
446 btsr->itr.read_finish = auxtrace_record__read_finish;
447 btsr->itr.alignment = sizeof(struct branch);
448 return &btsr->itr;
449}
450

source code of linux/tools/perf/arch/x86/util/intel-bts.c