xref: /openbmc/linux/tools/perf/arch/x86/util/intel-bts.c (revision 4f205687)
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
64 intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused,
65 			 struct perf_evlist *evlist __maybe_unused)
66 {
67 	return INTEL_BTS_AUXTRACE_PRIV_SIZE;
68 }
69 
70 static int intel_bts_info_fill(struct auxtrace_record *itr,
71 			       struct perf_session *session,
72 			       struct auxtrace_info_event *auxtrace_info,
73 			       size_t priv_size)
74 {
75 	struct intel_bts_recording *btsr =
76 			container_of(itr, struct intel_bts_recording, itr);
77 	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
78 	struct perf_event_mmap_page *pc;
79 	struct perf_tsc_conversion tc = { .time_mult = 0, };
80 	bool cap_user_time_zero = false;
81 	int err;
82 
83 	if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE)
84 		return -EINVAL;
85 
86 	if (!session->evlist->nr_mmaps)
87 		return -EINVAL;
88 
89 	pc = session->evlist->mmap[0].base;
90 	if (pc) {
91 		err = perf_read_tsc_conversion(pc, &tc);
92 		if (err) {
93 			if (err != -EOPNOTSUPP)
94 				return err;
95 		} else {
96 			cap_user_time_zero = tc.time_mult != 0;
97 		}
98 		if (!cap_user_time_zero)
99 			ui__warning("Intel BTS: TSC not available\n");
100 	}
101 
102 	auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS;
103 	auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type;
104 	auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift;
105 	auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult;
106 	auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero;
107 	auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero;
108 	auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode;
109 
110 	return 0;
111 }
112 
113 static int intel_bts_recording_options(struct auxtrace_record *itr,
114 				       struct perf_evlist *evlist,
115 				       struct record_opts *opts)
116 {
117 	struct intel_bts_recording *btsr =
118 			container_of(itr, struct intel_bts_recording, itr);
119 	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
120 	struct perf_evsel *evsel, *intel_bts_evsel = NULL;
121 	const struct cpu_map *cpus = evlist->cpus;
122 	bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
123 
124 	btsr->evlist = evlist;
125 	btsr->snapshot_mode = opts->auxtrace_snapshot_mode;
126 
127 	evlist__for_each(evlist, evsel) {
128 		if (evsel->attr.type == intel_bts_pmu->type) {
129 			if (intel_bts_evsel) {
130 				pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n");
131 				return -EINVAL;
132 			}
133 			evsel->attr.freq = 0;
134 			evsel->attr.sample_period = 1;
135 			intel_bts_evsel = evsel;
136 			opts->full_auxtrace = true;
137 		}
138 	}
139 
140 	if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
141 		pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
142 		return -EINVAL;
143 	}
144 
145 	if (!opts->full_auxtrace)
146 		return 0;
147 
148 	if (opts->full_auxtrace && !cpu_map__empty(cpus)) {
149 		pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
150 		return -EINVAL;
151 	}
152 
153 	/* Set default sizes for snapshot mode */
154 	if (opts->auxtrace_snapshot_mode) {
155 		if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
156 			if (privileged) {
157 				opts->auxtrace_mmap_pages = MiB(4) / page_size;
158 			} else {
159 				opts->auxtrace_mmap_pages = KiB(128) / page_size;
160 				if (opts->mmap_pages == UINT_MAX)
161 					opts->mmap_pages = KiB(256) / page_size;
162 			}
163 		} else if (!opts->auxtrace_mmap_pages && !privileged &&
164 			   opts->mmap_pages == UINT_MAX) {
165 			opts->mmap_pages = KiB(256) / page_size;
166 		}
167 		if (!opts->auxtrace_snapshot_size)
168 			opts->auxtrace_snapshot_size =
169 				opts->auxtrace_mmap_pages * (size_t)page_size;
170 		if (!opts->auxtrace_mmap_pages) {
171 			size_t sz = opts->auxtrace_snapshot_size;
172 
173 			sz = round_up(sz, page_size) / page_size;
174 			opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
175 		}
176 		if (opts->auxtrace_snapshot_size >
177 				opts->auxtrace_mmap_pages * (size_t)page_size) {
178 			pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
179 			       opts->auxtrace_snapshot_size,
180 			       opts->auxtrace_mmap_pages * (size_t)page_size);
181 			return -EINVAL;
182 		}
183 		if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
184 			pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
185 			return -EINVAL;
186 		}
187 		pr_debug2("Intel BTS snapshot size: %zu\n",
188 			  opts->auxtrace_snapshot_size);
189 	}
190 
191 	/* Set default sizes for full trace mode */
192 	if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
193 		if (privileged) {
194 			opts->auxtrace_mmap_pages = MiB(4) / page_size;
195 		} else {
196 			opts->auxtrace_mmap_pages = KiB(128) / page_size;
197 			if (opts->mmap_pages == UINT_MAX)
198 				opts->mmap_pages = KiB(256) / page_size;
199 		}
200 	}
201 
202 	/* Validate auxtrace_mmap_pages */
203 	if (opts->auxtrace_mmap_pages) {
204 		size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
205 		size_t min_sz;
206 
207 		if (opts->auxtrace_snapshot_mode)
208 			min_sz = KiB(4);
209 		else
210 			min_sz = KiB(8);
211 
212 		if (sz < min_sz || !is_power_of_2(sz)) {
213 			pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
214 			       min_sz / 1024);
215 			return -EINVAL;
216 		}
217 	}
218 
219 	if (intel_bts_evsel) {
220 		/*
221 		 * To obtain the auxtrace buffer file descriptor, the auxtrace event
222 		 * must come first.
223 		 */
224 		perf_evlist__to_front(evlist, intel_bts_evsel);
225 		/*
226 		 * In the case of per-cpu mmaps, we need the CPU on the
227 		 * AUX event.
228 		 */
229 		if (!cpu_map__empty(cpus))
230 			perf_evsel__set_sample_bit(intel_bts_evsel, CPU);
231 	}
232 
233 	/* Add dummy event to keep tracking */
234 	if (opts->full_auxtrace) {
235 		struct perf_evsel *tracking_evsel;
236 		int err;
237 
238 		err = parse_events(evlist, "dummy:u", NULL);
239 		if (err)
240 			return err;
241 
242 		tracking_evsel = perf_evlist__last(evlist);
243 
244 		perf_evlist__set_tracking_event(evlist, tracking_evsel);
245 
246 		tracking_evsel->attr.freq = 0;
247 		tracking_evsel->attr.sample_period = 1;
248 	}
249 
250 	return 0;
251 }
252 
253 static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
254 					    struct record_opts *opts,
255 					    const char *str)
256 {
257 	struct intel_bts_recording *btsr =
258 			container_of(itr, struct intel_bts_recording, itr);
259 	unsigned long long snapshot_size = 0;
260 	char *endptr;
261 
262 	if (str) {
263 		snapshot_size = strtoull(str, &endptr, 0);
264 		if (*endptr || snapshot_size > SIZE_MAX)
265 			return -1;
266 	}
267 
268 	opts->auxtrace_snapshot_mode = true;
269 	opts->auxtrace_snapshot_size = snapshot_size;
270 
271 	btsr->snapshot_size = snapshot_size;
272 
273 	return 0;
274 }
275 
276 static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
277 {
278 	return rdtsc();
279 }
280 
281 static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
282 					 int idx)
283 {
284 	const size_t sz = sizeof(struct intel_bts_snapshot_ref);
285 	int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
286 	struct intel_bts_snapshot_ref *refs;
287 
288 	if (!new_cnt)
289 		new_cnt = 16;
290 
291 	while (new_cnt <= idx)
292 		new_cnt *= 2;
293 
294 	refs = calloc(new_cnt, sz);
295 	if (!refs)
296 		return -ENOMEM;
297 
298 	memcpy(refs, btsr->snapshot_refs, cnt * sz);
299 
300 	btsr->snapshot_refs = refs;
301 	btsr->snapshot_ref_cnt = new_cnt;
302 
303 	return 0;
304 }
305 
306 static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
307 {
308 	int i;
309 
310 	for (i = 0; i < btsr->snapshot_ref_cnt; i++)
311 		zfree(&btsr->snapshot_refs[i].ref_buf);
312 	zfree(&btsr->snapshot_refs);
313 }
314 
315 static void intel_bts_recording_free(struct auxtrace_record *itr)
316 {
317 	struct intel_bts_recording *btsr =
318 			container_of(itr, struct intel_bts_recording, itr);
319 
320 	intel_bts_free_snapshot_refs(btsr);
321 	free(btsr);
322 }
323 
324 static int intel_bts_snapshot_start(struct auxtrace_record *itr)
325 {
326 	struct intel_bts_recording *btsr =
327 			container_of(itr, struct intel_bts_recording, itr);
328 	struct perf_evsel *evsel;
329 
330 	evlist__for_each(btsr->evlist, evsel) {
331 		if (evsel->attr.type == btsr->intel_bts_pmu->type)
332 			return perf_evsel__disable(evsel);
333 	}
334 	return -EINVAL;
335 }
336 
337 static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
338 {
339 	struct intel_bts_recording *btsr =
340 			container_of(itr, struct intel_bts_recording, itr);
341 	struct perf_evsel *evsel;
342 
343 	evlist__for_each(btsr->evlist, evsel) {
344 		if (evsel->attr.type == btsr->intel_bts_pmu->type)
345 			return perf_evsel__enable(evsel);
346 	}
347 	return -EINVAL;
348 }
349 
350 static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
351 {
352 	int i, a, b;
353 
354 	b = buf_size >> 3;
355 	a = b - 512;
356 	if (a < 0)
357 		a = 0;
358 
359 	for (i = a; i < b; i++) {
360 		if (data[i])
361 			return true;
362 	}
363 
364 	return false;
365 }
366 
367 static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
368 				   struct auxtrace_mmap *mm, unsigned char *data,
369 				   u64 *head, u64 *old)
370 {
371 	struct intel_bts_recording *btsr =
372 			container_of(itr, struct intel_bts_recording, itr);
373 	bool wrapped;
374 	int err;
375 
376 	pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
377 		  __func__, idx, (size_t)*old, (size_t)*head);
378 
379 	if (idx >= btsr->snapshot_ref_cnt) {
380 		err = intel_bts_alloc_snapshot_refs(btsr, idx);
381 		if (err)
382 			goto out_err;
383 	}
384 
385 	wrapped = btsr->snapshot_refs[idx].wrapped;
386 	if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) {
387 		btsr->snapshot_refs[idx].wrapped = true;
388 		wrapped = true;
389 	}
390 
391 	/*
392 	 * In full trace mode 'head' continually increases.  However in snapshot
393 	 * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
394 	 * are adjusted to match the full trace case which expects that 'old' is
395 	 * always less than 'head'.
396 	 */
397 	if (wrapped) {
398 		*old = *head;
399 		*head += mm->len;
400 	} else {
401 		if (mm->mask)
402 			*old &= mm->mask;
403 		else
404 			*old %= mm->len;
405 		if (*old > *head)
406 			*head += mm->len;
407 	}
408 
409 	pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
410 		  __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
411 
412 	return 0;
413 
414 out_err:
415 	pr_err("%s: failed, error %d\n", __func__, err);
416 	return err;
417 }
418 
419 static int intel_bts_read_finish(struct auxtrace_record *itr, int idx)
420 {
421 	struct intel_bts_recording *btsr =
422 			container_of(itr, struct intel_bts_recording, itr);
423 	struct perf_evsel *evsel;
424 
425 	evlist__for_each(btsr->evlist, evsel) {
426 		if (evsel->attr.type == btsr->intel_bts_pmu->type)
427 			return perf_evlist__enable_event_idx(btsr->evlist,
428 							     evsel, idx);
429 	}
430 	return -EINVAL;
431 }
432 
433 struct auxtrace_record *intel_bts_recording_init(int *err)
434 {
435 	struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME);
436 	struct intel_bts_recording *btsr;
437 
438 	if (!intel_bts_pmu)
439 		return NULL;
440 
441 	if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
442 		*err = -errno;
443 		return NULL;
444 	}
445 
446 	btsr = zalloc(sizeof(struct intel_bts_recording));
447 	if (!btsr) {
448 		*err = -ENOMEM;
449 		return NULL;
450 	}
451 
452 	btsr->intel_bts_pmu = intel_bts_pmu;
453 	btsr->itr.recording_options = intel_bts_recording_options;
454 	btsr->itr.info_priv_size = intel_bts_info_priv_size;
455 	btsr->itr.info_fill = intel_bts_info_fill;
456 	btsr->itr.free = intel_bts_recording_free;
457 	btsr->itr.snapshot_start = intel_bts_snapshot_start;
458 	btsr->itr.snapshot_finish = intel_bts_snapshot_finish;
459 	btsr->itr.find_snapshot = intel_bts_find_snapshot;
460 	btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options;
461 	btsr->itr.reference = intel_bts_reference;
462 	btsr->itr.read_finish = intel_bts_read_finish;
463 	btsr->itr.alignment = sizeof(struct branch);
464 	return &btsr->itr;
465 }
466