1// SPDX-License-Identifier: GPL-2.0
  2#include <errno.h>
  3#include <inttypes.h>
  4/* For the CLR_() macros */
  5#include <pthread.h>
  6
  7#include "evlist.h"
  8#include "evsel.h"
  9#include "thread_map.h"
 10#include "cpumap.h"
 11#include "tests.h"
 12#include <linux/err.h>
 13#include <linux/kernel.h>
 14
 15/*
 16 * This test will generate random numbers of calls to some getpid syscalls,
 17 * then establish an mmap for a group of events that are created to monitor
 18 * the syscalls.
 19 *
 20 * It will receive the events, using mmap, use its PERF_SAMPLE_ID generated
 21 * sample.id field to map back to its respective perf_evsel instance.
 22 *
 23 * Then it checks if the number of syscalls reported as perf events by
 24 * the kernel corresponds to the number of syscalls made.
 25 */
 26int test__basic_mmap(struct test *test __maybe_unused, int subtest __maybe_unused)
 27{
 28	int err = -1;
 29	union perf_event *event;
 30	struct thread_map *threads;
 31	struct cpu_map *cpus;
 32	struct perf_evlist *evlist;
 33	cpu_set_t cpu_set;
 34	const char *syscall_names[] = { "getsid", "getppid", "getpgid", };
 35	pid_t (*syscalls[])(void) = { (void *)getsid, getppid, (void*)getpgid };
 36#define nsyscalls ARRAY_SIZE(syscall_names)
 37	unsigned int nr_events[nsyscalls],
 38		     expected_nr_events[nsyscalls], i, j;
 39	struct perf_evsel *evsels[nsyscalls], *evsel;
 40	char sbuf[STRERR_BUFSIZE];
 41	struct perf_mmap *md;
 42
 43	threads = thread_map__new(-1, getpid(), UINT_MAX);
 44	if (threads == NULL) {
 45		pr_debug("thread_map__new\n");
 46		return -1;
 47	}
 48
 49	cpus = cpu_map__new(NULL);
 50	if (cpus == NULL) {
 51		pr_debug("cpu_map__new\n");
 52		goto out_free_threads;
 53	}
 54
 55	CPU_ZERO(&cpu_set);
 56	CPU_SET(cpus->map[0], &cpu_set);
 57	sched_setaffinity(0, sizeof(cpu_set), &cpu_set);
 58	if (sched_setaffinity(0, sizeof(cpu_set), &cpu_set) < 0) {
 59		pr_debug("sched_setaffinity() failed on CPU %d: %s ",
 60			 cpus->map[0], str_error_r(errno, sbuf, sizeof(sbuf)));
 61		goto out_free_cpus;
 62	}
 63
 64	evlist = perf_evlist__new();
 65	if (evlist == NULL) {
 66		pr_debug("perf_evlist__new\n");
 67		goto out_free_cpus;
 68	}
 69
 70	perf_evlist__set_maps(evlist, cpus, threads);
 71
 72	for (i = 0; i < nsyscalls; ++i) {
 73		char name[64];
 74
 75		snprintf(name, sizeof(name), "sys_enter_%s", syscall_names[i]);
 76		evsels[i] = perf_evsel__newtp("syscalls", name);
 77		if (IS_ERR(evsels[i])) {
 78			pr_debug("perf_evsel__new(%s)\n", name);
 79			goto out_delete_evlist;
 80		}
 81
 82		evsels[i]->attr.wakeup_events = 1;
 83		perf_evsel__set_sample_id(evsels[i], false);
 84
 85		perf_evlist__add(evlist, evsels[i]);
 86
 87		if (perf_evsel__open(evsels[i], cpus, threads) < 0) {
 88			pr_debug("failed to open counter: %s, "
 89				 "tweak /proc/sys/kernel/perf_event_paranoid?\n",
 90				 str_error_r(errno, sbuf, sizeof(sbuf)));
 91			goto out_delete_evlist;
 92		}
 93
 94		nr_events[i] = 0;
 95		expected_nr_events[i] = 1 + rand() % 127;
 96	}
 97
 98	if (perf_evlist__mmap(evlist, 128) < 0) {
 99		pr_debug("failed to mmap events: %d (%s)\n", errno,
100			 str_error_r(errno, sbuf, sizeof(sbuf)));
101		goto out_delete_evlist;
102	}
103
104	for (i = 0; i < nsyscalls; ++i)
105		for (j = 0; j < expected_nr_events[i]; ++j) {
106			int foo = syscalls[i]();
107			++foo;
108		}
109
110	md = &evlist->mmap[0];
111	if (perf_mmap__read_init(md) < 0)
112		goto out_init;
113
114	while ((event = perf_mmap__read_event(md)) != NULL) {
115		struct perf_sample sample;
116
117		if (event->header.type != PERF_RECORD_SAMPLE) {
118			pr_debug("unexpected %s event\n",
119				 perf_event__name(event->header.type));
120			goto out_delete_evlist;
121		}
122
123		err = perf_evlist__parse_sample(evlist, event, &sample);
124		if (err) {
125			pr_err("Can't parse sample, err = %d\n", err);
126			goto out_delete_evlist;
127		}
128
129		err = -1;
130		evsel = perf_evlist__id2evsel(evlist, sample.id);
131		if (evsel == NULL) {
132			pr_debug("event with id %" PRIu64
133				 " doesn't map to an evsel\n", sample.id);
134			goto out_delete_evlist;
135		}
136		nr_events[evsel->idx]++;
137		perf_mmap__consume(md);
138	}
139	perf_mmap__read_done(md);
140
141out_init:
142	err = 0;
143	evlist__for_each_entry(evlist, evsel) {
144		if (nr_events[evsel->idx] != expected_nr_events[evsel->idx]) {
145			pr_debug("expected %d %s events, got %d\n",
146				 expected_nr_events[evsel->idx],
147				 perf_evsel__name(evsel), nr_events[evsel->idx]);
148			err = -1;
149			goto out_delete_evlist;
150		}
151	}
152
153out_delete_evlist:
154	perf_evlist__delete(evlist);
155	cpus	= NULL;
156	threads = NULL;
157out_free_cpus:
158	cpu_map__put(cpus);
159out_free_threads:
160	thread_map__put(threads);
161	return err;
162}