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1 | /* |
2 | * intel-bts.c: Intel Processor Trace support | |
3 | * Copyright (c) 2013-2015, Intel Corporation. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms and conditions of the GNU General Public License, | |
7 | * version 2, as published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | */ | |
15 | ||
16 | #include <linux/kernel.h> | |
17 | #include <linux/types.h> | |
18 | #include <linux/bitops.h> | |
19 | #include <linux/log2.h> | |
20 | ||
21 | #include "../../util/cpumap.h" | |
22 | #include "../../util/evsel.h" | |
23 | #include "../../util/evlist.h" | |
24 | #include "../../util/session.h" | |
25 | #include "../../util/util.h" | |
26 | #include "../../util/pmu.h" | |
27 | #include "../../util/debug.h" | |
28 | #include "../../util/tsc.h" | |
29 | #include "../../util/auxtrace.h" | |
30 | #include "../../util/intel-bts.h" | |
31 | ||
32 | #define KiB(x) ((x) * 1024) | |
33 | #define MiB(x) ((x) * 1024 * 1024) | |
34 | #define KiB_MASK(x) (KiB(x) - 1) | |
35 | #define MiB_MASK(x) (MiB(x) - 1) | |
36 | ||
37 | #define INTEL_BTS_DFLT_SAMPLE_SIZE KiB(4) | |
38 | ||
39 | #define INTEL_BTS_MAX_SAMPLE_SIZE KiB(60) | |
40 | ||
41 | struct intel_bts_snapshot_ref { | |
42 | void *ref_buf; | |
43 | size_t ref_offset; | |
44 | bool wrapped; | |
45 | }; | |
46 | ||
47 | struct intel_bts_recording { | |
48 | struct auxtrace_record itr; | |
49 | struct perf_pmu *intel_bts_pmu; | |
50 | struct perf_evlist *evlist; | |
51 | bool snapshot_mode; | |
52 | size_t snapshot_size; | |
53 | int snapshot_ref_cnt; | |
54 | struct intel_bts_snapshot_ref *snapshot_refs; | |
55 | }; | |
56 | ||
57 | struct branch { | |
58 | u64 from; | |
59 | u64 to; | |
60 | u64 misc; | |
61 | }; | |
62 | ||
63 | static size_t intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused) | |
64 | { | |
65 | return INTEL_BTS_AUXTRACE_PRIV_SIZE; | |
66 | } | |
67 | ||
68 | static int intel_bts_info_fill(struct auxtrace_record *itr, | |
69 | struct perf_session *session, | |
70 | struct auxtrace_info_event *auxtrace_info, | |
71 | size_t priv_size) | |
72 | { | |
73 | struct intel_bts_recording *btsr = | |
74 | container_of(itr, struct intel_bts_recording, itr); | |
75 | struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu; | |
76 | struct perf_event_mmap_page *pc; | |
77 | struct perf_tsc_conversion tc = { .time_mult = 0, }; | |
78 | bool cap_user_time_zero = false; | |
79 | int err; | |
80 | ||
81 | if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE) | |
82 | return -EINVAL; | |
83 | ||
84 | if (!session->evlist->nr_mmaps) | |
85 | return -EINVAL; | |
86 | ||
87 | pc = session->evlist->mmap[0].base; | |
88 | if (pc) { | |
89 | err = perf_read_tsc_conversion(pc, &tc); | |
90 | if (err) { | |
91 | if (err != -EOPNOTSUPP) | |
92 | return err; | |
93 | } else { | |
94 | cap_user_time_zero = tc.time_mult != 0; | |
95 | } | |
96 | if (!cap_user_time_zero) | |
97 | ui__warning("Intel BTS: TSC not available\n"); | |
98 | } | |
99 | ||
100 | auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS; | |
101 | auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type; | |
102 | auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift; | |
103 | auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult; | |
104 | auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero; | |
105 | auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero; | |
106 | auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode; | |
107 | ||
108 | return 0; | |
109 | } | |
110 | ||
111 | static int intel_bts_recording_options(struct auxtrace_record *itr, | |
112 | struct perf_evlist *evlist, | |
113 | struct record_opts *opts) | |
114 | { | |
115 | struct intel_bts_recording *btsr = | |
116 | container_of(itr, struct intel_bts_recording, itr); | |
117 | struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu; | |
118 | struct perf_evsel *evsel, *intel_bts_evsel = NULL; | |
119 | const struct cpu_map *cpus = evlist->cpus; | |
120 | bool privileged = geteuid() == 0 || perf_event_paranoid() < 0; | |
121 | ||
122 | btsr->evlist = evlist; | |
123 | btsr->snapshot_mode = opts->auxtrace_snapshot_mode; | |
124 | ||
125 | evlist__for_each(evlist, evsel) { | |
126 | if (evsel->attr.type == intel_bts_pmu->type) { | |
127 | if (intel_bts_evsel) { | |
128 | pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n"); | |
129 | return -EINVAL; | |
130 | } | |
131 | evsel->attr.freq = 0; | |
132 | evsel->attr.sample_period = 1; | |
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 && !cpu_map__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(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 | perf_evlist__to_front(evlist, intel_bts_evsel); | |
223 | /* | |
224 | * In the case of per-cpu mmaps, we need the CPU on the | |
225 | * AUX event. | |
226 | */ | |
227 | if (!cpu_map__empty(cpus)) | |
228 | perf_evsel__set_sample_bit(intel_bts_evsel, CPU); | |
229 | } | |
230 | ||
231 | /* Add dummy event to keep tracking */ | |
232 | if (opts->full_auxtrace) { | |
233 | struct perf_evsel *tracking_evsel; | |
234 | int err; | |
235 | ||
236 | err = parse_events(evlist, "dummy:u", NULL); | |
237 | if (err) | |
238 | return err; | |
239 | ||
240 | tracking_evsel = perf_evlist__last(evlist); | |
241 | ||
242 | perf_evlist__set_tracking_event(evlist, tracking_evsel); | |
243 | ||
244 | tracking_evsel->attr.freq = 0; | |
245 | tracking_evsel->attr.sample_period = 1; | |
246 | } | |
247 | ||
248 | return 0; | |
249 | } | |
250 | ||
251 | static 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 | ||
274 | static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused) | |
275 | { | |
276 | return rdtsc(); | |
277 | } | |
278 | ||
279 | static 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 | ||
304 | static 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 | ||
313 | static 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 | ||
322 | static 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 perf_evsel *evsel; | |
327 | ||
328 | evlist__for_each(btsr->evlist, evsel) { | |
329 | if (evsel->attr.type == btsr->intel_bts_pmu->type) | |
330 | return perf_evlist__disable_event(btsr->evlist, evsel); | |
331 | } | |
332 | return -EINVAL; | |
333 | } | |
334 | ||
335 | static 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 perf_evsel *evsel; | |
340 | ||
341 | evlist__for_each(btsr->evlist, evsel) { | |
342 | if (evsel->attr.type == btsr->intel_bts_pmu->type) | |
343 | return perf_evlist__enable_event(btsr->evlist, evsel); | |
344 | } | |
345 | return -EINVAL; | |
346 | } | |
347 | ||
348 | static 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 | ||
365 | static 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((u64 *)data, 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 | ||
412 | out_err: | |
413 | pr_err("%s: failed, error %d\n", __func__, err); | |
414 | return err; | |
415 | } | |
416 | ||
417 | static int intel_bts_read_finish(struct auxtrace_record *itr, int idx) | |
418 | { | |
419 | struct intel_bts_recording *btsr = | |
420 | container_of(itr, struct intel_bts_recording, itr); | |
421 | struct perf_evsel *evsel; | |
422 | ||
423 | evlist__for_each(btsr->evlist, evsel) { | |
424 | if (evsel->attr.type == btsr->intel_bts_pmu->type) | |
425 | return perf_evlist__enable_event_idx(btsr->evlist, | |
426 | evsel, idx); | |
427 | } | |
428 | return -EINVAL; | |
429 | } | |
430 | ||
431 | struct auxtrace_record *intel_bts_recording_init(int *err) | |
432 | { | |
433 | struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME); | |
434 | struct intel_bts_recording *btsr; | |
435 | ||
436 | if (!intel_bts_pmu) | |
437 | return NULL; | |
438 | ||
439 | btsr = zalloc(sizeof(struct intel_bts_recording)); | |
440 | if (!btsr) { | |
441 | *err = -ENOMEM; | |
442 | return NULL; | |
443 | } | |
444 | ||
445 | btsr->intel_bts_pmu = intel_bts_pmu; | |
446 | btsr->itr.recording_options = intel_bts_recording_options; | |
447 | btsr->itr.info_priv_size = intel_bts_info_priv_size; | |
448 | btsr->itr.info_fill = intel_bts_info_fill; | |
449 | btsr->itr.free = intel_bts_recording_free; | |
450 | btsr->itr.snapshot_start = intel_bts_snapshot_start; | |
451 | btsr->itr.snapshot_finish = intel_bts_snapshot_finish; | |
452 | btsr->itr.find_snapshot = intel_bts_find_snapshot; | |
453 | btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options; | |
454 | btsr->itr.reference = intel_bts_reference; | |
455 | btsr->itr.read_finish = intel_bts_read_finish; | |
456 | btsr->itr.alignment = sizeof(struct branch); | |
457 | return &btsr->itr; | |
458 | } |