^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) #include <sys/mman.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) #include <inttypes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) #include <asm/bug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) #include <errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) #include <string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include <linux/ring_buffer.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <linux/perf_event.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #include <perf/mmap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <perf/event.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <internal/mmap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <internal/lib.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include "internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) bool overwrite, libperf_unmap_cb_t unmap_cb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) map->fd = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) map->overwrite = overwrite;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) map->unmap_cb = unmap_cb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) refcount_set(&map->refcnt, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) if (prev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) prev->next = map;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) size_t perf_mmap__mmap_len(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) return map->mask + 1 + page_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) int fd, int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) map->prev = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) map->mask = mp->mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) map->base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) MAP_SHARED, fd, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) if (map->base == MAP_FAILED) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) map->base = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) map->fd = fd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) map->cpu = cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) void perf_mmap__munmap(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) if (map && map->base != NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) munmap(map->base, perf_mmap__mmap_len(map));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) map->base = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) map->fd = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) refcount_set(&map->refcnt, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) if (map && map->unmap_cb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) map->unmap_cb(map);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) void perf_mmap__get(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) refcount_inc(&map->refcnt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) void perf_mmap__put(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) BUG_ON(map->base && refcount_read(&map->refcnt) == 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) if (refcount_dec_and_test(&map->refcnt))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) perf_mmap__munmap(map);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) static inline void perf_mmap__write_tail(struct perf_mmap *md, u64 tail)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) ring_buffer_write_tail(md->base, tail);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) u64 perf_mmap__read_head(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) return ring_buffer_read_head(map->base);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) static bool perf_mmap__empty(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) struct perf_event_mmap_page *pc = map->base;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) return perf_mmap__read_head(map) == map->prev && !pc->aux_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) void perf_mmap__consume(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) if (!map->overwrite) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) u64 old = map->prev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) perf_mmap__write_tail(map, old);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) if (refcount_read(&map->refcnt) == 1 && perf_mmap__empty(map))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) perf_mmap__put(map);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) struct perf_event_header *pheader;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) u64 evt_head = *start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) int size = mask + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) pr_debug2("%s: buf=%p, start=%"PRIx64"\n", __func__, buf, *start);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) pheader = (struct perf_event_header *)(buf + (*start & mask));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) while (true) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) if (evt_head - *start >= (unsigned int)size) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) pr_debug("Finished reading overwrite ring buffer: rewind\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) if (evt_head - *start > (unsigned int)size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) evt_head -= pheader->size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) *end = evt_head;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) pheader = (struct perf_event_header *)(buf + (evt_head & mask));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) if (pheader->size == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) pr_debug("Finished reading overwrite ring buffer: get start\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) *end = evt_head;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) evt_head += pheader->size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) pr_debug3("move evt_head: %"PRIx64"\n", evt_head);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) WARN_ONCE(1, "Shouldn't get here\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) * Report the start and end of the available data in ringbuffer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) static int __perf_mmap__read_init(struct perf_mmap *md)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) u64 head = perf_mmap__read_head(md);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) u64 old = md->prev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) unsigned char *data = md->base + page_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) unsigned long size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) md->start = md->overwrite ? head : old;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) md->end = md->overwrite ? old : head;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) if ((md->end - md->start) < md->flush)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) return -EAGAIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) size = md->end - md->start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) if (size > (unsigned long)(md->mask) + 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) if (!md->overwrite) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) md->prev = head;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) perf_mmap__consume(md);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) return -EAGAIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) * Backward ring buffer is full. We still have a chance to read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) * most of data from it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) if (overwrite_rb_find_range(data, md->mask, &md->start, &md->end))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) int perf_mmap__read_init(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) * Check if event was unmapped due to a POLLHUP/POLLERR.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) if (!refcount_read(&map->refcnt))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) return -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) return __perf_mmap__read_init(map);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) * Mandatory for overwrite mode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) * The direction of overwrite mode is backward.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) * The last perf_mmap__read() will set tail to map->core.prev.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) * Need to correct the map->core.prev to head which is the end of next read.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) void perf_mmap__read_done(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) * Check if event was unmapped due to a POLLHUP/POLLERR.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) if (!refcount_read(&map->refcnt))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) map->prev = perf_mmap__read_head(map);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) /* When check_messup is true, 'end' must points to a good entry */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) static union perf_event *perf_mmap__read(struct perf_mmap *map,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) u64 *startp, u64 end)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) unsigned char *data = map->base + page_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) union perf_event *event = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) int diff = end - *startp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) if (diff >= (int)sizeof(event->header)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) size_t size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) event = (union perf_event *)&data[*startp & map->mask];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) size = event->header.size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) if (size < sizeof(event->header) || diff < (int)size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) * Event straddles the mmap boundary -- header should always
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) * be inside due to u64 alignment of output.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) if ((*startp & map->mask) + size != ((*startp + size) & map->mask)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) unsigned int offset = *startp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) unsigned int len = min(sizeof(*event), size), cpy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) void *dst = map->event_copy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) cpy = min(map->mask + 1 - (offset & map->mask), len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) memcpy(dst, &data[offset & map->mask], cpy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) offset += cpy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) dst += cpy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) len -= cpy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) } while (len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) event = (union perf_event *)map->event_copy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) *startp += size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) return event;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) * Read event from ring buffer one by one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) * Return one event for each call.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) * Usage:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) * perf_mmap__read_init()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) * while(event = perf_mmap__read_event()) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) * //process the event
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) * perf_mmap__consume()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) * }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) * perf_mmap__read_done()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) union perf_event *perf_mmap__read_event(struct perf_mmap *map)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) union perf_event *event;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) * Check if event was unmapped due to a POLLHUP/POLLERR.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) if (!refcount_read(&map->refcnt))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) /* non-overwirte doesn't pause the ringbuffer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) if (!map->overwrite)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) map->end = perf_mmap__read_head(map);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) event = perf_mmap__read(map, &map->start, map->end);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) if (!map->overwrite)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) map->prev = map->start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) return event;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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