1// SPDX-License-Identifier: GPL-2.0-only
  2
  3#include "util/debug.h"
  4#include "util/evlist.h"
  5#include "util/evsel.h"
  6#include "util/mmap.h"
  7#include "util/perf_api_probe.h"
  8#include <perf/mmap.h>
  9#include <linux/perf_event.h>
 10#include <limits.h>
 11#include <pthread.h>
 12#include <sched.h>
 13#include <stdbool.h>
 14
 15int evlist__add_sb_event(struct evlist *evlist, struct perf_event_attr *attr,
 16			 evsel__sb_cb_t cb, void *data)
 17{
 18	struct evsel *evsel;
 19
 20	if (!attr->sample_id_all) {
 21		pr_warning("enabling sample_id_all for all side band events\n");
 22		attr->sample_id_all = 1;
 23	}
 24
 25	evsel = evsel__new_idx(attr, evlist->core.nr_entries);
 26	if (!evsel)
 27		return -1;
 28
 29	evsel->side_band.cb = cb;
 30	evsel->side_band.data = data;
 31	evlist__add(evlist, evsel);
 32	return 0;
 33}
 34
 35static void *perf_evlist__poll_thread(void *arg)
 36{
 37	struct evlist *evlist = arg;
 38	bool draining = false;
 39	int i, done = 0;
 40	/*
 41	 * In order to read symbols from other namespaces perf to needs to call
 42	 * setns(2).  This isn't permitted if the struct_fs has multiple users.
 43	 * unshare(2) the fs so that we may continue to setns into namespaces
 44	 * that we're observing when, for instance, reading the build-ids at
 45	 * the end of a 'perf record' session.
 46	 */
 47	unshare(CLONE_FS);
 48
 49	while (!done) {
 50		bool got_data = false;
 51
 52		if (evlist->thread.done)
 53			draining = true;
 54
 55		if (!draining)
 56			evlist__poll(evlist, 1000);
 57
 58		for (i = 0; i < evlist->core.nr_mmaps; i++) {
 59			struct mmap *map = &evlist->mmap[i];
 60			union perf_event *event;
 61
 62			if (perf_mmap__read_init(&map->core))
 63				continue;
 64			while ((event = perf_mmap__read_event(&map->core)) != NULL) {
 65				struct evsel *evsel = evlist__event2evsel(evlist, event);
 66
 67				if (evsel && evsel->side_band.cb)
 68					evsel->side_band.cb(event, evsel->side_band.data);
 69				else
 70					pr_warning("cannot locate proper evsel for the side band event\n");
 71
 72				perf_mmap__consume(&map->core);
 73				got_data = true;
 74			}
 75			perf_mmap__read_done(&map->core);
 76		}
 77
 78		if (draining && !got_data)
 79			break;
 80	}
 81	return NULL;
 82}
 83
 84void evlist__set_cb(struct evlist *evlist, evsel__sb_cb_t cb, void *data)
 85{
 86	struct evsel *evsel;
 87
 88	evlist__for_each_entry(evlist, evsel) {
 89		evsel->core.attr.sample_id_all    = 1;
 90		evsel->core.attr.watermark        = 1;
 91		evsel->core.attr.wakeup_watermark = 1;
 92		evsel->side_band.cb   = cb;
 93		evsel->side_band.data = data;
 94      }
 95}
 96
 97int evlist__start_sb_thread(struct evlist *evlist, struct target *target)
 98{
 99	struct evsel *counter;
100
101	if (!evlist)
102		return 0;
103
104	if (evlist__create_maps(evlist, target))
105		goto out_delete_evlist;
106
107	if (evlist->core.nr_entries > 1) {
108		bool can_sample_identifier = perf_can_sample_identifier();
109
110		evlist__for_each_entry(evlist, counter)
111			evsel__set_sample_id(counter, can_sample_identifier);
112
113		evlist__set_id_pos(evlist);
114	}
115
116	evlist__for_each_entry(evlist, counter) {
117		if (evsel__open(counter, evlist->core.user_requested_cpus,
118				evlist->core.threads) < 0)
119			goto out_delete_evlist;
120	}
121
122	if (evlist__mmap(evlist, UINT_MAX))
123		goto out_delete_evlist;
124
125	evlist__for_each_entry(evlist, counter) {
126		if (evsel__enable(counter))
127			goto out_delete_evlist;
128	}
129
130	evlist->thread.done = 0;
131	if (pthread_create(&evlist->thread.th, NULL, perf_evlist__poll_thread, evlist))
132		goto out_delete_evlist;
133
134	return 0;
135
136out_delete_evlist:
137	evlist__delete(evlist);
138	evlist = NULL;
139	return -1;
140}
141
142void evlist__stop_sb_thread(struct evlist *evlist)
143{
144	if (!evlist)
145		return;
146	evlist->thread.done = 1;
147	pthread_join(evlist->thread.th, NULL);
148	evlist__delete(evlist);
149}