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Move libperf from its current location under tools/perf to a separate directory under tools/lib/. Also change various paths (mainly includes) to reflect the libperf move to a separate directory and add a new directory under MANIFEST. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20191206210612.8676-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
276 lines
6.1 KiB
C
276 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <sys/mman.h>
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#include <inttypes.h>
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#include <asm/bug.h>
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#include <errno.h>
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#include <string.h>
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#include <linux/ring_buffer.h>
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#include <linux/perf_event.h>
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#include <perf/mmap.h>
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#include <perf/event.h>
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#include <internal/mmap.h>
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#include <internal/lib.h>
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#include <linux/kernel.h>
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#include "internal.h"
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void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,
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bool overwrite, libperf_unmap_cb_t unmap_cb)
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{
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map->fd = -1;
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map->overwrite = overwrite;
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map->unmap_cb = unmap_cb;
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refcount_set(&map->refcnt, 0);
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if (prev)
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prev->next = map;
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}
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size_t perf_mmap__mmap_len(struct perf_mmap *map)
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{
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return map->mask + 1 + page_size;
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}
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int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
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int fd, int cpu)
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{
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map->prev = 0;
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map->mask = mp->mask;
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map->base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,
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MAP_SHARED, fd, 0);
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if (map->base == MAP_FAILED) {
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map->base = NULL;
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return -1;
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}
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map->fd = fd;
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map->cpu = cpu;
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return 0;
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}
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void perf_mmap__munmap(struct perf_mmap *map)
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{
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if (map && map->base != NULL) {
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munmap(map->base, perf_mmap__mmap_len(map));
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map->base = NULL;
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map->fd = -1;
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refcount_set(&map->refcnt, 0);
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}
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if (map && map->unmap_cb)
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map->unmap_cb(map);
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}
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void perf_mmap__get(struct perf_mmap *map)
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{
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refcount_inc(&map->refcnt);
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}
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void perf_mmap__put(struct perf_mmap *map)
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{
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BUG_ON(map->base && refcount_read(&map->refcnt) == 0);
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if (refcount_dec_and_test(&map->refcnt))
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perf_mmap__munmap(map);
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}
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static inline void perf_mmap__write_tail(struct perf_mmap *md, u64 tail)
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{
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ring_buffer_write_tail(md->base, tail);
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}
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u64 perf_mmap__read_head(struct perf_mmap *map)
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{
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return ring_buffer_read_head(map->base);
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}
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static bool perf_mmap__empty(struct perf_mmap *map)
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{
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struct perf_event_mmap_page *pc = map->base;
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return perf_mmap__read_head(map) == map->prev && !pc->aux_size;
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}
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void perf_mmap__consume(struct perf_mmap *map)
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{
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if (!map->overwrite) {
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u64 old = map->prev;
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perf_mmap__write_tail(map, old);
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}
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if (refcount_read(&map->refcnt) == 1 && perf_mmap__empty(map))
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perf_mmap__put(map);
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}
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static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
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{
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struct perf_event_header *pheader;
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u64 evt_head = *start;
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int size = mask + 1;
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pr_debug2("%s: buf=%p, start=%"PRIx64"\n", __func__, buf, *start);
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pheader = (struct perf_event_header *)(buf + (*start & mask));
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while (true) {
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if (evt_head - *start >= (unsigned int)size) {
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pr_debug("Finished reading overwrite ring buffer: rewind\n");
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if (evt_head - *start > (unsigned int)size)
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evt_head -= pheader->size;
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*end = evt_head;
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return 0;
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}
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pheader = (struct perf_event_header *)(buf + (evt_head & mask));
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if (pheader->size == 0) {
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pr_debug("Finished reading overwrite ring buffer: get start\n");
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*end = evt_head;
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return 0;
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}
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evt_head += pheader->size;
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pr_debug3("move evt_head: %"PRIx64"\n", evt_head);
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}
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WARN_ONCE(1, "Shouldn't get here\n");
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return -1;
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}
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/*
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* Report the start and end of the available data in ringbuffer
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*/
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static int __perf_mmap__read_init(struct perf_mmap *md)
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{
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u64 head = perf_mmap__read_head(md);
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u64 old = md->prev;
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unsigned char *data = md->base + page_size;
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unsigned long size;
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md->start = md->overwrite ? head : old;
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md->end = md->overwrite ? old : head;
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if ((md->end - md->start) < md->flush)
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return -EAGAIN;
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size = md->end - md->start;
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if (size > (unsigned long)(md->mask) + 1) {
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if (!md->overwrite) {
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WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
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md->prev = head;
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perf_mmap__consume(md);
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return -EAGAIN;
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}
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/*
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* Backward ring buffer is full. We still have a chance to read
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* most of data from it.
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*/
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if (overwrite_rb_find_range(data, md->mask, &md->start, &md->end))
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return -EINVAL;
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}
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return 0;
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}
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int perf_mmap__read_init(struct perf_mmap *map)
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{
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/*
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* Check if event was unmapped due to a POLLHUP/POLLERR.
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*/
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if (!refcount_read(&map->refcnt))
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return -ENOENT;
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return __perf_mmap__read_init(map);
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}
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/*
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* Mandatory for overwrite mode
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* The direction of overwrite mode is backward.
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* The last perf_mmap__read() will set tail to map->core.prev.
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* Need to correct the map->core.prev to head which is the end of next read.
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*/
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void perf_mmap__read_done(struct perf_mmap *map)
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{
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/*
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* Check if event was unmapped due to a POLLHUP/POLLERR.
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*/
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if (!refcount_read(&map->refcnt))
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return;
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map->prev = perf_mmap__read_head(map);
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}
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/* When check_messup is true, 'end' must points to a good entry */
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static union perf_event *perf_mmap__read(struct perf_mmap *map,
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u64 *startp, u64 end)
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{
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unsigned char *data = map->base + page_size;
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union perf_event *event = NULL;
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int diff = end - *startp;
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if (diff >= (int)sizeof(event->header)) {
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size_t size;
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event = (union perf_event *)&data[*startp & map->mask];
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size = event->header.size;
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if (size < sizeof(event->header) || diff < (int)size)
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return NULL;
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/*
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* Event straddles the mmap boundary -- header should always
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* be inside due to u64 alignment of output.
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*/
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if ((*startp & map->mask) + size != ((*startp + size) & map->mask)) {
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unsigned int offset = *startp;
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unsigned int len = min(sizeof(*event), size), cpy;
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void *dst = map->event_copy;
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do {
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cpy = min(map->mask + 1 - (offset & map->mask), len);
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memcpy(dst, &data[offset & map->mask], cpy);
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offset += cpy;
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dst += cpy;
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len -= cpy;
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} while (len);
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event = (union perf_event *)map->event_copy;
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}
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*startp += size;
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}
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return event;
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}
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/*
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* Read event from ring buffer one by one.
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* Return one event for each call.
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*
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* Usage:
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* perf_mmap__read_init()
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* while(event = perf_mmap__read_event()) {
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* //process the event
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* perf_mmap__consume()
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* }
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* perf_mmap__read_done()
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*/
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union perf_event *perf_mmap__read_event(struct perf_mmap *map)
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{
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union perf_event *event;
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/*
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* Check if event was unmapped due to a POLLHUP/POLLERR.
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*/
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if (!refcount_read(&map->refcnt))
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return NULL;
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/* non-overwirte doesn't pause the ringbuffer */
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if (!map->overwrite)
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map->end = perf_mmap__read_head(map);
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event = perf_mmap__read(map, &map->start, map->end);
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if (!map->overwrite)
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map->prev = map->start;
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return event;
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}
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