xref: /linux/tools/perf/arch/arm64/util/arm-spe.c (revision e7d759f31ca295d589f7420719c311870bb3166f)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Arm Statistical Profiling Extensions (SPE) support
4  * Copyright (c) 2017-2018, Arm Ltd.
5  */
6 
7 #include <linux/kernel.h>
8 #include <linux/types.h>
9 #include <linux/bitops.h>
10 #include <linux/log2.h>
11 #include <linux/zalloc.h>
12 #include <time.h>
13 
14 #include "../../../util/cpumap.h"
15 #include "../../../util/event.h"
16 #include "../../../util/evsel.h"
17 #include "../../../util/evsel_config.h"
18 #include "../../../util/evlist.h"
19 #include "../../../util/session.h"
20 #include <internal/lib.h> // page_size
21 #include "../../../util/pmu.h"
22 #include "../../../util/debug.h"
23 #include "../../../util/auxtrace.h"
24 #include "../../../util/record.h"
25 #include "../../../util/arm-spe.h"
26 #include <tools/libc_compat.h> // reallocarray
27 
28 #define KiB(x) ((x) * 1024)
29 #define MiB(x) ((x) * 1024 * 1024)
30 
31 struct arm_spe_recording {
32 	struct auxtrace_record		itr;
33 	struct perf_pmu			*arm_spe_pmu;
34 	struct evlist		*evlist;
35 	int			wrapped_cnt;
36 	bool			*wrapped;
37 };
38 
39 static size_t
40 arm_spe_info_priv_size(struct auxtrace_record *itr __maybe_unused,
41 		       struct evlist *evlist __maybe_unused)
42 {
43 	return ARM_SPE_AUXTRACE_PRIV_SIZE;
44 }
45 
46 static int arm_spe_info_fill(struct auxtrace_record *itr,
47 			     struct perf_session *session,
48 			     struct perf_record_auxtrace_info *auxtrace_info,
49 			     size_t priv_size)
50 {
51 	struct arm_spe_recording *sper =
52 			container_of(itr, struct arm_spe_recording, itr);
53 	struct perf_pmu *arm_spe_pmu = sper->arm_spe_pmu;
54 
55 	if (priv_size != ARM_SPE_AUXTRACE_PRIV_SIZE)
56 		return -EINVAL;
57 
58 	if (!session->evlist->core.nr_mmaps)
59 		return -EINVAL;
60 
61 	auxtrace_info->type = PERF_AUXTRACE_ARM_SPE;
62 	auxtrace_info->priv[ARM_SPE_PMU_TYPE] = arm_spe_pmu->type;
63 
64 	return 0;
65 }
66 
67 static void
68 arm_spe_snapshot_resolve_auxtrace_defaults(struct record_opts *opts,
69 					   bool privileged)
70 {
71 	/*
72 	 * The default snapshot size is the auxtrace mmap size. If neither auxtrace mmap size nor
73 	 * snapshot size is specified, then the default is 4MiB for privileged users, 128KiB for
74 	 * unprivileged users.
75 	 *
76 	 * The default auxtrace mmap size is 4MiB/page_size for privileged users, 128KiB for
77 	 * unprivileged users. If an unprivileged user does not specify mmap pages, the mmap pages
78 	 * will be reduced from the default 512KiB/page_size to 256KiB/page_size, otherwise the
79 	 * user is likely to get an error as they exceed their mlock limmit.
80 	 */
81 
82 	/*
83 	 * No size were given to '-S' or '-m,', so go with the default
84 	 */
85 	if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
86 		if (privileged) {
87 			opts->auxtrace_mmap_pages = MiB(4) / page_size;
88 		} else {
89 			opts->auxtrace_mmap_pages = KiB(128) / page_size;
90 			if (opts->mmap_pages == UINT_MAX)
91 				opts->mmap_pages = KiB(256) / page_size;
92 		}
93 	} else if (!opts->auxtrace_mmap_pages && !privileged && opts->mmap_pages == UINT_MAX) {
94 		opts->mmap_pages = KiB(256) / page_size;
95 	}
96 
97 	/*
98 	 * '-m,xyz' was specified but no snapshot size, so make the snapshot size as big as the
99 	 * auxtrace mmap area.
100 	 */
101 	if (!opts->auxtrace_snapshot_size)
102 		opts->auxtrace_snapshot_size = opts->auxtrace_mmap_pages * (size_t)page_size;
103 
104 	/*
105 	 * '-Sxyz' was specified but no auxtrace mmap area, so make the auxtrace mmap area big
106 	 * enough to fit the requested snapshot size.
107 	 */
108 	if (!opts->auxtrace_mmap_pages) {
109 		size_t sz = opts->auxtrace_snapshot_size;
110 
111 		sz = round_up(sz, page_size) / page_size;
112 		opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
113 	}
114 }
115 
116 static __u64 arm_spe_pmu__sample_period(const struct perf_pmu *arm_spe_pmu)
117 {
118 	static __u64 sample_period;
119 
120 	if (sample_period)
121 		return sample_period;
122 
123 	/*
124 	 * If kernel driver doesn't advertise a minimum,
125 	 * use max allowable by PMSIDR_EL1.INTERVAL
126 	 */
127 	if (perf_pmu__scan_file(arm_spe_pmu, "caps/min_interval", "%llu",
128 				&sample_period) != 1) {
129 		pr_debug("arm_spe driver doesn't advertise a min. interval. Using 4096\n");
130 		sample_period = 4096;
131 	}
132 	return sample_period;
133 }
134 
135 static int arm_spe_recording_options(struct auxtrace_record *itr,
136 				     struct evlist *evlist,
137 				     struct record_opts *opts)
138 {
139 	struct arm_spe_recording *sper =
140 			container_of(itr, struct arm_spe_recording, itr);
141 	struct perf_pmu *arm_spe_pmu = sper->arm_spe_pmu;
142 	struct evsel *evsel, *arm_spe_evsel = NULL;
143 	struct perf_cpu_map *cpus = evlist->core.user_requested_cpus;
144 	bool privileged = perf_event_paranoid_check(-1);
145 	struct evsel *tracking_evsel;
146 	int err;
147 	u64 bit;
148 
149 	sper->evlist = evlist;
150 
151 	evlist__for_each_entry(evlist, evsel) {
152 		if (evsel->core.attr.type == arm_spe_pmu->type) {
153 			if (arm_spe_evsel) {
154 				pr_err("There may be only one " ARM_SPE_PMU_NAME "x event\n");
155 				return -EINVAL;
156 			}
157 			evsel->core.attr.freq = 0;
158 			evsel->core.attr.sample_period = arm_spe_pmu__sample_period(arm_spe_pmu);
159 			evsel->needs_auxtrace_mmap = true;
160 			arm_spe_evsel = evsel;
161 			opts->full_auxtrace = true;
162 		}
163 	}
164 
165 	if (!opts->full_auxtrace)
166 		return 0;
167 
168 	/*
169 	 * we are in snapshot mode.
170 	 */
171 	if (opts->auxtrace_snapshot_mode) {
172 		/*
173 		 * Command arguments '-Sxyz' and/or '-m,xyz' are missing, so fill those in with
174 		 * default values.
175 		 */
176 		if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages)
177 			arm_spe_snapshot_resolve_auxtrace_defaults(opts, privileged);
178 
179 		/*
180 		 * Snapshot size can't be bigger than the auxtrace area.
181 		 */
182 		if (opts->auxtrace_snapshot_size > opts->auxtrace_mmap_pages * (size_t)page_size) {
183 			pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
184 			       opts->auxtrace_snapshot_size,
185 			       opts->auxtrace_mmap_pages * (size_t)page_size);
186 			return -EINVAL;
187 		}
188 
189 		/*
190 		 * Something went wrong somewhere - this shouldn't happen.
191 		 */
192 		if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
193 			pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
194 			return -EINVAL;
195 		}
196 	}
197 
198 	/* We are in full trace mode but '-m,xyz' wasn't specified */
199 	if (!opts->auxtrace_mmap_pages) {
200 		if (privileged) {
201 			opts->auxtrace_mmap_pages = MiB(4) / page_size;
202 		} else {
203 			opts->auxtrace_mmap_pages = KiB(128) / page_size;
204 			if (opts->mmap_pages == UINT_MAX)
205 				opts->mmap_pages = KiB(256) / page_size;
206 		}
207 	}
208 
209 	/* Validate auxtrace_mmap_pages */
210 	if (opts->auxtrace_mmap_pages) {
211 		size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
212 		size_t min_sz = KiB(8);
213 
214 		if (sz < min_sz || !is_power_of_2(sz)) {
215 			pr_err("Invalid mmap size for ARM SPE: must be at least %zuKiB and a power of 2\n",
216 			       min_sz / 1024);
217 			return -EINVAL;
218 		}
219 	}
220 
221 	if (opts->auxtrace_snapshot_mode)
222 		pr_debug2("%sx snapshot size: %zu\n", ARM_SPE_PMU_NAME,
223 			  opts->auxtrace_snapshot_size);
224 
225 	/*
226 	 * To obtain the auxtrace buffer file descriptor, the auxtrace event
227 	 * must come first.
228 	 */
229 	evlist__to_front(evlist, arm_spe_evsel);
230 
231 	/*
232 	 * In the case of per-cpu mmaps, sample CPU for AUX event;
233 	 * also enable the timestamp tracing for samples correlation.
234 	 */
235 	if (!perf_cpu_map__has_any_cpu_or_is_empty(cpus)) {
236 		evsel__set_sample_bit(arm_spe_evsel, CPU);
237 		evsel__set_config_if_unset(arm_spe_pmu, arm_spe_evsel,
238 					   "ts_enable", 1);
239 	}
240 
241 	/*
242 	 * Set this only so that perf report knows that SPE generates memory info. It has no effect
243 	 * on the opening of the event or the SPE data produced.
244 	 */
245 	evsel__set_sample_bit(arm_spe_evsel, DATA_SRC);
246 
247 	/*
248 	 * The PHYS_ADDR flag does not affect the driver behaviour, it is used to
249 	 * inform that the resulting output's SPE samples contain physical addresses
250 	 * where applicable.
251 	 */
252 	bit = perf_pmu__format_bits(arm_spe_pmu, "pa_enable");
253 	if (arm_spe_evsel->core.attr.config & bit)
254 		evsel__set_sample_bit(arm_spe_evsel, PHYS_ADDR);
255 
256 	/* Add dummy event to keep tracking */
257 	err = parse_event(evlist, "dummy:u");
258 	if (err)
259 		return err;
260 
261 	tracking_evsel = evlist__last(evlist);
262 	evlist__set_tracking_event(evlist, tracking_evsel);
263 
264 	tracking_evsel->core.attr.freq = 0;
265 	tracking_evsel->core.attr.sample_period = 1;
266 
267 	/* In per-cpu case, always need the time of mmap events etc */
268 	if (!perf_cpu_map__has_any_cpu_or_is_empty(cpus)) {
269 		evsel__set_sample_bit(tracking_evsel, TIME);
270 		evsel__set_sample_bit(tracking_evsel, CPU);
271 
272 		/* also track task context switch */
273 		if (!record_opts__no_switch_events(opts))
274 			tracking_evsel->core.attr.context_switch = 1;
275 	}
276 
277 	return 0;
278 }
279 
280 static int arm_spe_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
281 					 struct record_opts *opts,
282 					 const char *str)
283 {
284 	unsigned long long snapshot_size = 0;
285 	char *endptr;
286 
287 	if (str) {
288 		snapshot_size = strtoull(str, &endptr, 0);
289 		if (*endptr || snapshot_size > SIZE_MAX)
290 			return -1;
291 	}
292 
293 	opts->auxtrace_snapshot_mode = true;
294 	opts->auxtrace_snapshot_size = snapshot_size;
295 
296 	return 0;
297 }
298 
299 static int arm_spe_snapshot_start(struct auxtrace_record *itr)
300 {
301 	struct arm_spe_recording *ptr =
302 			container_of(itr, struct arm_spe_recording, itr);
303 	struct evsel *evsel;
304 
305 	evlist__for_each_entry(ptr->evlist, evsel) {
306 		if (evsel->core.attr.type == ptr->arm_spe_pmu->type)
307 			return evsel__disable(evsel);
308 	}
309 	return -EINVAL;
310 }
311 
312 static int arm_spe_snapshot_finish(struct auxtrace_record *itr)
313 {
314 	struct arm_spe_recording *ptr =
315 			container_of(itr, struct arm_spe_recording, itr);
316 	struct evsel *evsel;
317 
318 	evlist__for_each_entry(ptr->evlist, evsel) {
319 		if (evsel->core.attr.type == ptr->arm_spe_pmu->type)
320 			return evsel__enable(evsel);
321 	}
322 	return -EINVAL;
323 }
324 
325 static int arm_spe_alloc_wrapped_array(struct arm_spe_recording *ptr, int idx)
326 {
327 	bool *wrapped;
328 	int cnt = ptr->wrapped_cnt, new_cnt, i;
329 
330 	/*
331 	 * No need to allocate, so return early.
332 	 */
333 	if (idx < cnt)
334 		return 0;
335 
336 	/*
337 	 * Make ptr->wrapped as big as idx.
338 	 */
339 	new_cnt = idx + 1;
340 
341 	/*
342 	 * Free'ed in arm_spe_recording_free().
343 	 */
344 	wrapped = reallocarray(ptr->wrapped, new_cnt, sizeof(bool));
345 	if (!wrapped)
346 		return -ENOMEM;
347 
348 	/*
349 	 * init new allocated values.
350 	 */
351 	for (i = cnt; i < new_cnt; i++)
352 		wrapped[i] = false;
353 
354 	ptr->wrapped_cnt = new_cnt;
355 	ptr->wrapped = wrapped;
356 
357 	return 0;
358 }
359 
360 static bool arm_spe_buffer_has_wrapped(unsigned char *buffer,
361 				      size_t buffer_size, u64 head)
362 {
363 	u64 i, watermark;
364 	u64 *buf = (u64 *)buffer;
365 	size_t buf_size = buffer_size;
366 
367 	/*
368 	 * Defensively handle the case where head might be continually increasing - if its value is
369 	 * equal or greater than the size of the ring buffer, then we can safely determine it has
370 	 * wrapped around. Otherwise, continue to detect if head might have wrapped.
371 	 */
372 	if (head >= buffer_size)
373 		return true;
374 
375 	/*
376 	 * We want to look the very last 512 byte (chosen arbitrarily) in the ring buffer.
377 	 */
378 	watermark = buf_size - 512;
379 
380 	/*
381 	 * The value of head is somewhere within the size of the ring buffer. This can be that there
382 	 * hasn't been enough data to fill the ring buffer yet or the trace time was so long that
383 	 * head has numerically wrapped around.  To find we need to check if we have data at the
384 	 * very end of the ring buffer.  We can reliably do this because mmap'ed pages are zeroed
385 	 * out and there is a fresh mapping with every new session.
386 	 */
387 
388 	/*
389 	 * head is less than 512 byte from the end of the ring buffer.
390 	 */
391 	if (head > watermark)
392 		watermark = head;
393 
394 	/*
395 	 * Speed things up by using 64 bit transactions (see "u64 *buf" above)
396 	 */
397 	watermark /= sizeof(u64);
398 	buf_size /= sizeof(u64);
399 
400 	/*
401 	 * If we find trace data at the end of the ring buffer, head has been there and has
402 	 * numerically wrapped around at least once.
403 	 */
404 	for (i = watermark; i < buf_size; i++)
405 		if (buf[i])
406 			return true;
407 
408 	return false;
409 }
410 
411 static int arm_spe_find_snapshot(struct auxtrace_record *itr, int idx,
412 				  struct auxtrace_mmap *mm, unsigned char *data,
413 				  u64 *head, u64 *old)
414 {
415 	int err;
416 	bool wrapped;
417 	struct arm_spe_recording *ptr =
418 			container_of(itr, struct arm_spe_recording, itr);
419 
420 	/*
421 	 * Allocate memory to keep track of wrapping if this is the first
422 	 * time we deal with this *mm.
423 	 */
424 	if (idx >= ptr->wrapped_cnt) {
425 		err = arm_spe_alloc_wrapped_array(ptr, idx);
426 		if (err)
427 			return err;
428 	}
429 
430 	/*
431 	 * Check to see if *head has wrapped around.  If it hasn't only the
432 	 * amount of data between *head and *old is snapshot'ed to avoid
433 	 * bloating the perf.data file with zeros.  But as soon as *head has
434 	 * wrapped around the entire size of the AUX ring buffer it taken.
435 	 */
436 	wrapped = ptr->wrapped[idx];
437 	if (!wrapped && arm_spe_buffer_has_wrapped(data, mm->len, *head)) {
438 		wrapped = true;
439 		ptr->wrapped[idx] = true;
440 	}
441 
442 	pr_debug3("%s: mmap index %d old head %zu new head %zu size %zu\n",
443 		  __func__, idx, (size_t)*old, (size_t)*head, mm->len);
444 
445 	/*
446 	 * No wrap has occurred, we can just use *head and *old.
447 	 */
448 	if (!wrapped)
449 		return 0;
450 
451 	/*
452 	 * *head has wrapped around - adjust *head and *old to pickup the
453 	 * entire content of the AUX buffer.
454 	 */
455 	if (*head >= mm->len) {
456 		*old = *head - mm->len;
457 	} else {
458 		*head += mm->len;
459 		*old = *head - mm->len;
460 	}
461 
462 	return 0;
463 }
464 
465 static u64 arm_spe_reference(struct auxtrace_record *itr __maybe_unused)
466 {
467 	struct timespec ts;
468 
469 	clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
470 
471 	return ts.tv_sec ^ ts.tv_nsec;
472 }
473 
474 static void arm_spe_recording_free(struct auxtrace_record *itr)
475 {
476 	struct arm_spe_recording *sper =
477 			container_of(itr, struct arm_spe_recording, itr);
478 
479 	zfree(&sper->wrapped);
480 	free(sper);
481 }
482 
483 struct auxtrace_record *arm_spe_recording_init(int *err,
484 					       struct perf_pmu *arm_spe_pmu)
485 {
486 	struct arm_spe_recording *sper;
487 
488 	if (!arm_spe_pmu) {
489 		*err = -ENODEV;
490 		return NULL;
491 	}
492 
493 	sper = zalloc(sizeof(struct arm_spe_recording));
494 	if (!sper) {
495 		*err = -ENOMEM;
496 		return NULL;
497 	}
498 
499 	sper->arm_spe_pmu = arm_spe_pmu;
500 	sper->itr.pmu = arm_spe_pmu;
501 	sper->itr.snapshot_start = arm_spe_snapshot_start;
502 	sper->itr.snapshot_finish = arm_spe_snapshot_finish;
503 	sper->itr.find_snapshot = arm_spe_find_snapshot;
504 	sper->itr.parse_snapshot_options = arm_spe_parse_snapshot_options;
505 	sper->itr.recording_options = arm_spe_recording_options;
506 	sper->itr.info_priv_size = arm_spe_info_priv_size;
507 	sper->itr.info_fill = arm_spe_info_fill;
508 	sper->itr.free = arm_spe_recording_free;
509 	sper->itr.reference = arm_spe_reference;
510 	sper->itr.read_finish = auxtrace_record__read_finish;
511 	sper->itr.alignment = 0;
512 
513 	*err = 0;
514 	return &sper->itr;
515 }
516 
517 void
518 arm_spe_pmu_default_config(const struct perf_pmu *arm_spe_pmu, struct perf_event_attr *attr)
519 {
520 	attr->sample_period = arm_spe_pmu__sample_period(arm_spe_pmu);
521 }
522