1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Test backward bit in event attribute, read ring buffer from end to
  4 * beginning
  5 */
  6
  7#include <perf.h>
  8#include <evlist.h>
  9#include <sys/prctl.h>
 10#include "tests.h"
 11#include "debug.h"
 12#include <errno.h>
 13
 14#define NR_ITERS 111
 15
 16static void testcase(void)
 17{
 18	int i;
 19
 20	for (i = 0; i < NR_ITERS; i++) {
 21		char proc_name[10];
 22
 23		snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);
 24		prctl(PR_SET_NAME, proc_name);
 25	}
 26}
 27
 28static int count_samples(struct perf_evlist *evlist, int *sample_count,
 29			 int *comm_count)
 30{
 31	int i;
 32
 33	for (i = 0; i < evlist->nr_mmaps; i++) {
 34		struct perf_mmap *map = &evlist->overwrite_mmap[i];
 35		union perf_event *event;
 36
 37		perf_mmap__read_init(map);
 38		while ((event = perf_mmap__read_event(map)) != NULL) {
 39			const u32 type = event->header.type;
 40
 41			switch (type) {
 42			case PERF_RECORD_SAMPLE:
 43				(*sample_count)++;
 44				break;
 45			case PERF_RECORD_COMM:
 46				(*comm_count)++;
 47				break;
 48			default:
 49				pr_err("Unexpected record of type %d\n", type);
 50				return TEST_FAIL;
 51			}
 52		}
 53		perf_mmap__read_done(map);
 54	}
 55	return TEST_OK;
 56}
 57
 58static int do_test(struct perf_evlist *evlist, int mmap_pages,
 59		   int *sample_count, int *comm_count)
 60{
 61	int err;
 62	char sbuf[STRERR_BUFSIZE];
 63
 64	err = perf_evlist__mmap(evlist, mmap_pages);
 65	if (err < 0) {
 66		pr_debug("perf_evlist__mmap: %s\n",
 67			 str_error_r(errno, sbuf, sizeof(sbuf)));
 68		return TEST_FAIL;
 69	}
 70
 71	perf_evlist__enable(evlist);
 72	testcase();
 73	perf_evlist__disable(evlist);
 74
 75	err = count_samples(evlist, sample_count, comm_count);
 76	perf_evlist__munmap(evlist);
 77	return err;
 78}
 79
 80
 81int test__backward_ring_buffer(struct test *test __maybe_unused, int subtest __maybe_unused)
 82{
 83	int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
 84	char pid[16], sbuf[STRERR_BUFSIZE];
 85	struct perf_evlist *evlist;
 86	struct perf_evsel *evsel __maybe_unused;
 87	struct parse_events_error parse_error;
 88	struct record_opts opts = {
 89		.target = {
 90			.uid = UINT_MAX,
 91			.uses_mmap = true,
 92		},
 93		.freq	      = 0,
 94		.mmap_pages   = 256,
 95		.default_interval = 1,
 96	};
 97
 98	snprintf(pid, sizeof(pid), "%d", getpid());
 99	pid[sizeof(pid) - 1] = '\0';
100	opts.target.tid = opts.target.pid = pid;
101
102	evlist = perf_evlist__new();
103	if (!evlist) {
104		pr_debug("Not enough memory to create evlist\n");
105		return TEST_FAIL;
106	}
107
108	err = perf_evlist__create_maps(evlist, &opts.target);
109	if (err < 0) {
110		pr_debug("Not enough memory to create thread/cpu maps\n");
111		goto out_delete_evlist;
112	}
113
114	bzero(&parse_error, sizeof(parse_error));
115	/*
116	 * Set backward bit, ring buffer should be writing from end. Record
117	 * it in aux evlist
118	 */
119	err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
120	if (err) {
121		pr_debug("Failed to parse tracepoint event, try use root\n");
122		ret = TEST_SKIP;
123		goto out_delete_evlist;
124	}
125
126	perf_evlist__config(evlist, &opts, NULL);
127
128	err = perf_evlist__open(evlist);
129	if (err < 0) {
130		pr_debug("perf_evlist__open: %s\n",
131			 str_error_r(errno, sbuf, sizeof(sbuf)));
132		goto out_delete_evlist;
133	}
134
135	ret = TEST_FAIL;
136	err = do_test(evlist, opts.mmap_pages, &sample_count,
137		      &comm_count);
138	if (err != TEST_OK)
139		goto out_delete_evlist;
140
141	if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
142		pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
143		       sample_count, comm_count);
144		goto out_delete_evlist;
145	}
146
147	err = do_test(evlist, 1, &sample_count, &comm_count);
148	if (err != TEST_OK)
149		goto out_delete_evlist;
150
151	ret = TEST_OK;
152out_delete_evlist:
153	perf_evlist__delete(evlist);
154	return ret;
155}