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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/pmu.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
intel_bts_info_priv_size(struct auxtrace_record * itr __maybe_unused,struct evlist * evlist __maybe_unused)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 
intel_bts_info_fill(struct auxtrace_record * itr,struct perf_session * session,struct perf_record_auxtrace_info * auxtrace_info,size_t priv_size)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);
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("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 
intel_bts_recording_options(struct auxtrace_record * itr,struct evlist * evlist,struct record_opts * opts)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.cpus;
114 	bool privileged = perf_event_paranoid_check(-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 			intel_bts_evsel = evsel;
133 			opts->full_auxtrace = true;
134 		}
135 	}
136 
137 	if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
138 		pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
139 		return -EINVAL;
140 	}
141 
142 	if (!opts->full_auxtrace)
143 		return 0;
144 
145 	if (opts->full_auxtrace && !perf_cpu_map__empty(cpus)) {
146 		pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
147 		return -EINVAL;
148 	}
149 
150 	/* Set default sizes for snapshot mode */
151 	if (opts->auxtrace_snapshot_mode) {
152 		if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
153 			if (privileged) {
154 				opts->auxtrace_mmap_pages = MiB(4) / page_size;
155 			} else {
156 				opts->auxtrace_mmap_pages = KiB(128) / page_size;
157 				if (opts->mmap_pages == UINT_MAX)
158 					opts->mmap_pages = KiB(256) / page_size;
159 			}
160 		} else if (!opts->auxtrace_mmap_pages && !privileged &&
161 			   opts->mmap_pages == UINT_MAX) {
162 			opts->mmap_pages = KiB(256) / page_size;
163 		}
164 		if (!opts->auxtrace_snapshot_size)
165 			opts->auxtrace_snapshot_size =
166 				opts->auxtrace_mmap_pages * (size_t)page_size;
167 		if (!opts->auxtrace_mmap_pages) {
168 			size_t sz = opts->auxtrace_snapshot_size;
169 
170 			sz = round_up(sz, page_size) / page_size;
171 			opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
172 		}
173 		if (opts->auxtrace_snapshot_size >
174 				opts->auxtrace_mmap_pages * (size_t)page_size) {
175 			pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
176 			       opts->auxtrace_snapshot_size,
177 			       opts->auxtrace_mmap_pages * (size_t)page_size);
178 			return -EINVAL;
179 		}
180 		if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
181 			pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
182 			return -EINVAL;
183 		}
184 		pr_debug2("Intel BTS snapshot size: %zu\n",
185 			  opts->auxtrace_snapshot_size);
186 	}
187 
188 	/* Set default sizes for full trace mode */
189 	if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
190 		if (privileged) {
191 			opts->auxtrace_mmap_pages = MiB(4) / page_size;
192 		} else {
193 			opts->auxtrace_mmap_pages = KiB(128) / page_size;
194 			if (opts->mmap_pages == UINT_MAX)
195 				opts->mmap_pages = KiB(256) / page_size;
196 		}
197 	}
198 
199 	/* Validate auxtrace_mmap_pages */
200 	if (opts->auxtrace_mmap_pages) {
201 		size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
202 		size_t min_sz;
203 
204 		if (opts->auxtrace_snapshot_mode)
205 			min_sz = KiB(4);
206 		else
207 			min_sz = KiB(8);
208 
209 		if (sz < min_sz || !is_power_of_2(sz)) {
210 			pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
211 			       min_sz / 1024);
212 			return -EINVAL;
213 		}
214 	}
215 
216 	if (intel_bts_evsel) {
217 		/*
218 		 * To obtain the auxtrace buffer file descriptor, the auxtrace event
219 		 * must come first.
220 		 */
221 		evlist__to_front(evlist, intel_bts_evsel);
222 		/*
223 		 * In the case of per-cpu mmaps, we need the CPU on the
224 		 * AUX event.
225 		 */
226 		if (!perf_cpu_map__empty(cpus))
227 			evsel__set_sample_bit(intel_bts_evsel, CPU);
228 	}
229 
230 	/* Add dummy event to keep tracking */
231 	if (opts->full_auxtrace) {
232 		struct evsel *tracking_evsel;
233 		int err;
234 
235 		err = parse_events(evlist, "dummy:u", NULL);
236 		if (err)
237 			return err;
238 
239 		tracking_evsel = evlist__last(evlist);
240 
241 		evlist__set_tracking_event(evlist, tracking_evsel);
242 
243 		tracking_evsel->core.attr.freq = 0;
244 		tracking_evsel->core.attr.sample_period = 1;
245 	}
246 
247 	return 0;
248 }
249 
intel_bts_parse_snapshot_options(struct auxtrace_record * itr,struct record_opts * opts,const char * str)250 static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
251 					    struct record_opts *opts,
252 					    const char *str)
253 {
254 	struct intel_bts_recording *btsr =
255 			container_of(itr, struct intel_bts_recording, itr);
256 	unsigned long long snapshot_size = 0;
257 	char *endptr;
258 
259 	if (str) {
260 		snapshot_size = strtoull(str, &endptr, 0);
261 		if (*endptr || snapshot_size > SIZE_MAX)
262 			return -1;
263 	}
264 
265 	opts->auxtrace_snapshot_mode = true;
266 	opts->auxtrace_snapshot_size = snapshot_size;
267 
268 	btsr->snapshot_size = snapshot_size;
269 
270 	return 0;
271 }
272 
intel_bts_reference(struct auxtrace_record * itr __maybe_unused)273 static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
274 {
275 	return rdtsc();
276 }
277 
intel_bts_alloc_snapshot_refs(struct intel_bts_recording * btsr,int idx)278 static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
279 					 int idx)
280 {
281 	const size_t sz = sizeof(struct intel_bts_snapshot_ref);
282 	int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
283 	struct intel_bts_snapshot_ref *refs;
284 
285 	if (!new_cnt)
286 		new_cnt = 16;
287 
288 	while (new_cnt <= idx)
289 		new_cnt *= 2;
290 
291 	refs = calloc(new_cnt, sz);
292 	if (!refs)
293 		return -ENOMEM;
294 
295 	memcpy(refs, btsr->snapshot_refs, cnt * sz);
296 
297 	btsr->snapshot_refs = refs;
298 	btsr->snapshot_ref_cnt = new_cnt;
299 
300 	return 0;
301 }
302 
intel_bts_free_snapshot_refs(struct intel_bts_recording * btsr)303 static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
304 {
305 	int i;
306 
307 	for (i = 0; i < btsr->snapshot_ref_cnt; i++)
308 		zfree(&btsr->snapshot_refs[i].ref_buf);
309 	zfree(&btsr->snapshot_refs);
310 }
311 
intel_bts_recording_free(struct auxtrace_record * itr)312 static void intel_bts_recording_free(struct auxtrace_record *itr)
313 {
314 	struct intel_bts_recording *btsr =
315 			container_of(itr, struct intel_bts_recording, itr);
316 
317 	intel_bts_free_snapshot_refs(btsr);
318 	free(btsr);
319 }
320 
intel_bts_snapshot_start(struct auxtrace_record * itr)321 static int intel_bts_snapshot_start(struct auxtrace_record *itr)
322 {
323 	struct intel_bts_recording *btsr =
324 			container_of(itr, struct intel_bts_recording, itr);
325 	struct evsel *evsel;
326 
327 	evlist__for_each_entry(btsr->evlist, evsel) {
328 		if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
329 			return evsel__disable(evsel);
330 	}
331 	return -EINVAL;
332 }
333 
intel_bts_snapshot_finish(struct auxtrace_record * itr)334 static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
335 {
336 	struct intel_bts_recording *btsr =
337 			container_of(itr, struct intel_bts_recording, itr);
338 	struct evsel *evsel;
339 
340 	evlist__for_each_entry(btsr->evlist, evsel) {
341 		if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
342 			return evsel__enable(evsel);
343 	}
344 	return -EINVAL;
345 }
346 
intel_bts_first_wrap(u64 * data,size_t buf_size)347 static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
348 {
349 	int i, a, b;
350 
351 	b = buf_size >> 3;
352 	a = b - 512;
353 	if (a < 0)
354 		a = 0;
355 
356 	for (i = a; i < b; i++) {
357 		if (data[i])
358 			return true;
359 	}
360 
361 	return false;
362 }
363 
intel_bts_find_snapshot(struct auxtrace_record * itr,int idx,struct auxtrace_mmap * mm,unsigned char * data,u64 * head,u64 * old)364 static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
365 				   struct auxtrace_mmap *mm, unsigned char *data,
366 				   u64 *head, u64 *old)
367 {
368 	struct intel_bts_recording *btsr =
369 			container_of(itr, struct intel_bts_recording, itr);
370 	bool wrapped;
371 	int err;
372 
373 	pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
374 		  __func__, idx, (size_t)*old, (size_t)*head);
375 
376 	if (idx >= btsr->snapshot_ref_cnt) {
377 		err = intel_bts_alloc_snapshot_refs(btsr, idx);
378 		if (err)
379 			goto out_err;
380 	}
381 
382 	wrapped = btsr->snapshot_refs[idx].wrapped;
383 	if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) {
384 		btsr->snapshot_refs[idx].wrapped = true;
385 		wrapped = true;
386 	}
387 
388 	/*
389 	 * In full trace mode 'head' continually increases.  However in snapshot
390 	 * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
391 	 * are adjusted to match the full trace case which expects that 'old' is
392 	 * always less than 'head'.
393 	 */
394 	if (wrapped) {
395 		*old = *head;
396 		*head += mm->len;
397 	} else {
398 		if (mm->mask)
399 			*old &= mm->mask;
400 		else
401 			*old %= mm->len;
402 		if (*old > *head)
403 			*head += mm->len;
404 	}
405 
406 	pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
407 		  __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
408 
409 	return 0;
410 
411 out_err:
412 	pr_err("%s: failed, error %d\n", __func__, err);
413 	return err;
414 }
415 
intel_bts_recording_init(int * err)416 struct auxtrace_record *intel_bts_recording_init(int *err)
417 {
418 	struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME);
419 	struct intel_bts_recording *btsr;
420 
421 	if (!intel_bts_pmu)
422 		return NULL;
423 
424 	if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
425 		*err = -errno;
426 		return NULL;
427 	}
428 
429 	btsr = zalloc(sizeof(struct intel_bts_recording));
430 	if (!btsr) {
431 		*err = -ENOMEM;
432 		return NULL;
433 	}
434 
435 	btsr->intel_bts_pmu = intel_bts_pmu;
436 	btsr->itr.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