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 | |
33 | struct intel_bts_snapshot_ref { |
34 | void *ref_buf; |
35 | size_t ref_offset; |
36 | bool wrapped; |
37 | }; |
38 | |
39 | struct 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 | |
49 | struct branch { |
50 | u64 from; |
51 | u64 to; |
52 | u64 misc; |
53 | }; |
54 | |
55 | static size_t |
56 | intel_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 | |
62 | static 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 | |
105 | static 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__has_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__has_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 | |
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 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 | |
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 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 | |
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(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 | |
412 | out_err: |
413 | pr_err("%s: failed, error %d\n" , __func__, err); |
414 | return err; |
415 | } |
416 | |
417 | struct 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.pmu = intel_bts_pmu; |
438 | btsr->itr.recording_options = intel_bts_recording_options; |
439 | btsr->itr.info_priv_size = intel_bts_info_priv_size; |
440 | btsr->itr.info_fill = intel_bts_info_fill; |
441 | btsr->itr.free = intel_bts_recording_free; |
442 | btsr->itr.snapshot_start = intel_bts_snapshot_start; |
443 | btsr->itr.snapshot_finish = intel_bts_snapshot_finish; |
444 | btsr->itr.find_snapshot = intel_bts_find_snapshot; |
445 | btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options; |
446 | btsr->itr.reference = intel_bts_reference; |
447 | btsr->itr.read_finish = auxtrace_record__read_finish; |
448 | btsr->itr.alignment = sizeof(struct branch); |
449 | return &btsr->itr; |
450 | } |
451 | |