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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011-2017, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
4 *
5 * Parts came from evlist.c builtin-{top,stat,record}.c, see those files for further
6 * copyright notes.
7 */
8
9#include <sys/mman.h>
10#include <inttypes.h>
11#include <asm/bug.h>
12#include <linux/zalloc.h>
13#include <stdlib.h>
14#include <string.h>
15#include <unistd.h> // sysconf()
16#ifdef HAVE_LIBNUMA_SUPPORT
17#include <numaif.h>
18#endif
19#include "cpumap.h"
20#include "debug.h"
21#include "event.h"
22#include "mmap.h"
23#include "../perf.h"
24#include <internal/lib.h> /* page_size */
25
26size_t perf_mmap__mmap_len(struct mmap *map)
27{
28 return map->core.mask + 1 + page_size;
29}
30
31/* When check_messup is true, 'end' must points to a good entry */
32static union perf_event *perf_mmap__read(struct mmap *map,
33 u64 *startp, u64 end)
34{
35 unsigned char *data = map->core.base + page_size;
36 union perf_event *event = NULL;
37 int diff = end - *startp;
38
39 if (diff >= (int)sizeof(event->header)) {
40 size_t size;
41
42 event = (union perf_event *)&data[*startp & map->core.mask];
43 size = event->header.size;
44
45 if (size < sizeof(event->header) || diff < (int)size)
46 return NULL;
47
48 /*
49 * Event straddles the mmap boundary -- header should always
50 * be inside due to u64 alignment of output.
51 */
52 if ((*startp & map->core.mask) + size != ((*startp + size) & map->core.mask)) {
53 unsigned int offset = *startp;
54 unsigned int len = min(sizeof(*event), size), cpy;
55 void *dst = map->core.event_copy;
56
57 do {
58 cpy = min(map->core.mask + 1 - (offset & map->core.mask), len);
59 memcpy(dst, &data[offset & map->core.mask], cpy);
60 offset += cpy;
61 dst += cpy;
62 len -= cpy;
63 } while (len);
64
65 event = (union perf_event *)map->core.event_copy;
66 }
67
68 *startp += size;
69 }
70
71 return event;
72}
73
74/*
75 * Read event from ring buffer one by one.
76 * Return one event for each call.
77 *
78 * Usage:
79 * perf_mmap__read_init()
80 * while(event = perf_mmap__read_event()) {
81 * //process the event
82 * perf_mmap__consume()
83 * }
84 * perf_mmap__read_done()
85 */
86union perf_event *perf_mmap__read_event(struct mmap *map)
87{
88 union perf_event *event;
89
90 /*
91 * Check if event was unmapped due to a POLLHUP/POLLERR.
92 */
93 if (!refcount_read(&map->core.refcnt))
94 return NULL;
95
96 /* non-overwirte doesn't pause the ringbuffer */
97 if (!map->core.overwrite)
98 map->core.end = perf_mmap__read_head(map);
99
100 event = perf_mmap__read(map, &map->core.start, map->core.end);
101
102 if (!map->core.overwrite)
103 map->core.prev = map->core.start;
104
105 return event;
106}
107
108static bool perf_mmap__empty(struct mmap *map)
109{
110 return perf_mmap__read_head(map) == map->core.prev && !map->auxtrace_mmap.base;
111}
112
113void perf_mmap__get(struct mmap *map)
114{
115 refcount_inc(&map->core.refcnt);
116}
117
118void perf_mmap__put(struct mmap *map)
119{
120 BUG_ON(map->core.base && refcount_read(&map->core.refcnt) == 0);
121
122 if (refcount_dec_and_test(&map->core.refcnt))
123 perf_mmap__munmap(map);
124}
125
126void perf_mmap__consume(struct mmap *map)
127{
128 if (!map->core.overwrite) {
129 u64 old = map->core.prev;
130
131 perf_mmap__write_tail(map, old);
132 }
133
134 if (refcount_read(&map->core.refcnt) == 1 && perf_mmap__empty(map))
135 perf_mmap__put(map);
136}
137
138int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,
139 struct auxtrace_mmap_params *mp __maybe_unused,
140 void *userpg __maybe_unused,
141 int fd __maybe_unused)
142{
143 return 0;
144}
145
146void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused)
147{
148}
149
150void __weak auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp __maybe_unused,
151 off_t auxtrace_offset __maybe_unused,
152 unsigned int auxtrace_pages __maybe_unused,
153 bool auxtrace_overwrite __maybe_unused)
154{
155}
156
157void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __maybe_unused,
158 struct evlist *evlist __maybe_unused,
159 int idx __maybe_unused,
160 bool per_cpu __maybe_unused)
161{
162}
163
164#ifdef HAVE_AIO_SUPPORT
165static int perf_mmap__aio_enabled(struct mmap *map)
166{
167 return map->aio.nr_cblocks > 0;
168}
169
170#ifdef HAVE_LIBNUMA_SUPPORT
171static int perf_mmap__aio_alloc(struct mmap *map, int idx)
172{
173 map->aio.data[idx] = mmap(NULL, perf_mmap__mmap_len(map), PROT_READ|PROT_WRITE,
174 MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
175 if (map->aio.data[idx] == MAP_FAILED) {
176 map->aio.data[idx] = NULL;
177 return -1;
178 }
179
180 return 0;
181}
182
183static void perf_mmap__aio_free(struct mmap *map, int idx)
184{
185 if (map->aio.data[idx]) {
186 munmap(map->aio.data[idx], perf_mmap__mmap_len(map));
187 map->aio.data[idx] = NULL;
188 }
189}
190
191static int perf_mmap__aio_bind(struct mmap *map, int idx, int cpu, int affinity)
192{
193 void *data;
194 size_t mmap_len;
195 unsigned long node_mask;
196
197 if (affinity != PERF_AFFINITY_SYS && cpu__max_node() > 1) {
198 data = map->aio.data[idx];
199 mmap_len = perf_mmap__mmap_len(map);
200 node_mask = 1UL << cpu__get_node(cpu);
201 if (mbind(data, mmap_len, MPOL_BIND, &node_mask, 1, 0)) {
202 pr_err("Failed to bind [%p-%p] AIO buffer to node %d: error %m\n",
203 data, data + mmap_len, cpu__get_node(cpu));
204 return -1;
205 }
206 }
207
208 return 0;
209}
210#else /* !HAVE_LIBNUMA_SUPPORT */
211static int perf_mmap__aio_alloc(struct mmap *map, int idx)
212{
213 map->aio.data[idx] = malloc(perf_mmap__mmap_len(map));
214 if (map->aio.data[idx] == NULL)
215 return -1;
216
217 return 0;
218}
219
220static void perf_mmap__aio_free(struct mmap *map, int idx)
221{
222 zfree(&(map->aio.data[idx]));
223}
224
225static int perf_mmap__aio_bind(struct mmap *map __maybe_unused, int idx __maybe_unused,
226 int cpu __maybe_unused, int affinity __maybe_unused)
227{
228 return 0;
229}
230#endif
231
232static int perf_mmap__aio_mmap(struct mmap *map, struct mmap_params *mp)
233{
234 int delta_max, i, prio, ret;
235
236 map->aio.nr_cblocks = mp->nr_cblocks;
237 if (map->aio.nr_cblocks) {
238 map->aio.aiocb = calloc(map->aio.nr_cblocks, sizeof(struct aiocb *));
239 if (!map->aio.aiocb) {
240 pr_debug2("failed to allocate aiocb for data buffer, error %m\n");
241 return -1;
242 }
243 map->aio.cblocks = calloc(map->aio.nr_cblocks, sizeof(struct aiocb));
244 if (!map->aio.cblocks) {
245 pr_debug2("failed to allocate cblocks for data buffer, error %m\n");
246 return -1;
247 }
248 map->aio.data = calloc(map->aio.nr_cblocks, sizeof(void *));
249 if (!map->aio.data) {
250 pr_debug2("failed to allocate data buffer, error %m\n");
251 return -1;
252 }
253 delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
254 for (i = 0; i < map->aio.nr_cblocks; ++i) {
255 ret = perf_mmap__aio_alloc(map, i);
256 if (ret == -1) {
257 pr_debug2("failed to allocate data buffer area, error %m");
258 return -1;
259 }
260 ret = perf_mmap__aio_bind(map, i, map->core.cpu, mp->affinity);
261 if (ret == -1)
262 return -1;
263 /*
264 * Use cblock.aio_fildes value different from -1
265 * to denote started aio write operation on the
266 * cblock so it requires explicit record__aio_sync()
267 * call prior the cblock may be reused again.
268 */
269 map->aio.cblocks[i].aio_fildes = -1;
270 /*
271 * Allocate cblocks with priority delta to have
272 * faster aio write system calls because queued requests
273 * are kept in separate per-prio queues and adding
274 * a new request will iterate thru shorter per-prio
275 * list. Blocks with numbers higher than
276 * _SC_AIO_PRIO_DELTA_MAX go with priority 0.
277 */
278 prio = delta_max - i;
279 map->aio.cblocks[i].aio_reqprio = prio >= 0 ? prio : 0;
280 }
281 }
282
283 return 0;
284}
285
286static void perf_mmap__aio_munmap(struct mmap *map)
287{
288 int i;
289
290 for (i = 0; i < map->aio.nr_cblocks; ++i)
291 perf_mmap__aio_free(map, i);
292 if (map->aio.data)
293 zfree(&map->aio.data);
294 zfree(&map->aio.cblocks);
295 zfree(&map->aio.aiocb);
296}
297#else /* !HAVE_AIO_SUPPORT */
298static int perf_mmap__aio_enabled(struct mmap *map __maybe_unused)
299{
300 return 0;
301}
302
303static int perf_mmap__aio_mmap(struct mmap *map __maybe_unused,
304 struct mmap_params *mp __maybe_unused)
305{
306 return 0;
307}
308
309static void perf_mmap__aio_munmap(struct mmap *map __maybe_unused)
310{
311}
312#endif
313
314void perf_mmap__munmap(struct mmap *map)
315{
316 perf_mmap__aio_munmap(map);
317 if (map->data != NULL) {
318 munmap(map->data, perf_mmap__mmap_len(map));
319 map->data = NULL;
320 }
321 if (map->core.base != NULL) {
322 munmap(map->core.base, perf_mmap__mmap_len(map));
323 map->core.base = NULL;
324 map->core.fd = -1;
325 refcount_set(&map->core.refcnt, 0);
326 }
327 auxtrace_mmap__munmap(&map->auxtrace_mmap);
328}
329
330static void build_node_mask(int node, cpu_set_t *mask)
331{
332 int c, cpu, nr_cpus;
333 const struct perf_cpu_map *cpu_map = NULL;
334
335 cpu_map = cpu_map__online();
336 if (!cpu_map)
337 return;
338
339 nr_cpus = perf_cpu_map__nr(cpu_map);
340 for (c = 0; c < nr_cpus; c++) {
341 cpu = cpu_map->map[c]; /* map c index to online cpu index */
342 if (cpu__get_node(cpu) == node)
343 CPU_SET(cpu, mask);
344 }
345}
346
347static void perf_mmap__setup_affinity_mask(struct mmap *map, struct mmap_params *mp)
348{
349 CPU_ZERO(&map->affinity_mask);
350 if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1)
351 build_node_mask(cpu__get_node(map->core.cpu), &map->affinity_mask);
352 else if (mp->affinity == PERF_AFFINITY_CPU)
353 CPU_SET(map->core.cpu, &map->affinity_mask);
354}
355
356int perf_mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, int cpu)
357{
358 /*
359 * The last one will be done at perf_mmap__consume(), so that we
360 * make sure we don't prevent tools from consuming every last event in
361 * the ring buffer.
362 *
363 * I.e. we can get the POLLHUP meaning that the fd doesn't exist
364 * anymore, but the last events for it are still in the ring buffer,
365 * waiting to be consumed.
366 *
367 * Tools can chose to ignore this at their own discretion, but the
368 * evlist layer can't just drop it when filtering events in
369 * perf_evlist__filter_pollfd().
370 */
371 refcount_set(&map->core.refcnt, 2);
372 map->core.prev = 0;
373 map->core.mask = mp->mask;
374 map->core.base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,
375 MAP_SHARED, fd, 0);
376 if (map->core.base == MAP_FAILED) {
377 pr_debug2("failed to mmap perf event ring buffer, error %d\n",
378 errno);
379 map->core.base = NULL;
380 return -1;
381 }
382 map->core.fd = fd;
383 map->core.cpu = cpu;
384
385 perf_mmap__setup_affinity_mask(map, mp);
386
387 map->core.flush = mp->flush;
388
389 map->comp_level = mp->comp_level;
390
391 if (map->comp_level && !perf_mmap__aio_enabled(map)) {
392 map->data = mmap(NULL, perf_mmap__mmap_len(map), PROT_READ|PROT_WRITE,
393 MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
394 if (map->data == MAP_FAILED) {
395 pr_debug2("failed to mmap data buffer, error %d\n",
396 errno);
397 map->data = NULL;
398 return -1;
399 }
400 }
401
402 if (auxtrace_mmap__mmap(&map->auxtrace_mmap,
403 &mp->auxtrace_mp, map->core.base, fd))
404 return -1;
405
406 return perf_mmap__aio_mmap(map, mp);
407}
408
409static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
410{
411 struct perf_event_header *pheader;
412 u64 evt_head = *start;
413 int size = mask + 1;
414
415 pr_debug2("%s: buf=%p, start=%"PRIx64"\n", __func__, buf, *start);
416 pheader = (struct perf_event_header *)(buf + (*start & mask));
417 while (true) {
418 if (evt_head - *start >= (unsigned int)size) {
419 pr_debug("Finished reading overwrite ring buffer: rewind\n");
420 if (evt_head - *start > (unsigned int)size)
421 evt_head -= pheader->size;
422 *end = evt_head;
423 return 0;
424 }
425
426 pheader = (struct perf_event_header *)(buf + (evt_head & mask));
427
428 if (pheader->size == 0) {
429 pr_debug("Finished reading overwrite ring buffer: get start\n");
430 *end = evt_head;
431 return 0;
432 }
433
434 evt_head += pheader->size;
435 pr_debug3("move evt_head: %"PRIx64"\n", evt_head);
436 }
437 WARN_ONCE(1, "Shouldn't get here\n");
438 return -1;
439}
440
441/*
442 * Report the start and end of the available data in ringbuffer
443 */
444static int __perf_mmap__read_init(struct mmap *md)
445{
446 u64 head = perf_mmap__read_head(md);
447 u64 old = md->core.prev;
448 unsigned char *data = md->core.base + page_size;
449 unsigned long size;
450
451 md->core.start = md->core.overwrite ? head : old;
452 md->core.end = md->core.overwrite ? old : head;
453
454 if ((md->core.end - md->core.start) < md->core.flush)
455 return -EAGAIN;
456
457 size = md->core.end - md->core.start;
458 if (size > (unsigned long)(md->core.mask) + 1) {
459 if (!md->core.overwrite) {
460 WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
461
462 md->core.prev = head;
463 perf_mmap__consume(md);
464 return -EAGAIN;
465 }
466
467 /*
468 * Backward ring buffer is full. We still have a chance to read
469 * most of data from it.
470 */
471 if (overwrite_rb_find_range(data, md->core.mask, &md->core.start, &md->core.end))
472 return -EINVAL;
473 }
474
475 return 0;
476}
477
478int perf_mmap__read_init(struct mmap *map)
479{
480 /*
481 * Check if event was unmapped due to a POLLHUP/POLLERR.
482 */
483 if (!refcount_read(&map->core.refcnt))
484 return -ENOENT;
485
486 return __perf_mmap__read_init(map);
487}
488
489int perf_mmap__push(struct mmap *md, void *to,
490 int push(struct mmap *map, void *to, void *buf, size_t size))
491{
492 u64 head = perf_mmap__read_head(md);
493 unsigned char *data = md->core.base + page_size;
494 unsigned long size;
495 void *buf;
496 int rc = 0;
497
498 rc = perf_mmap__read_init(md);
499 if (rc < 0)
500 return (rc == -EAGAIN) ? 1 : -1;
501
502 size = md->core.end - md->core.start;
503
504 if ((md->core.start & md->core.mask) + size != (md->core.end & md->core.mask)) {
505 buf = &data[md->core.start & md->core.mask];
506 size = md->core.mask + 1 - (md->core.start & md->core.mask);
507 md->core.start += size;
508
509 if (push(md, to, buf, size) < 0) {
510 rc = -1;
511 goto out;
512 }
513 }
514
515 buf = &data[md->core.start & md->core.mask];
516 size = md->core.end - md->core.start;
517 md->core.start += size;
518
519 if (push(md, to, buf, size) < 0) {
520 rc = -1;
521 goto out;
522 }
523
524 md->core.prev = head;
525 perf_mmap__consume(md);
526out:
527 return rc;
528}
529
530/*
531 * Mandatory for overwrite mode
532 * The direction of overwrite mode is backward.
533 * The last perf_mmap__read() will set tail to map->core.prev.
534 * Need to correct the map->core.prev to head which is the end of next read.
535 */
536void perf_mmap__read_done(struct mmap *map)
537{
538 /*
539 * Check if event was unmapped due to a POLLHUP/POLLERR.
540 */
541 if (!refcount_read(&map->core.refcnt))
542 return;
543
544 map->core.prev = perf_mmap__read_head(map);
545}