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 <evlist.h>
  8#include <sys/prctl.h>
  9#include "record.h"
 10#include "tests.h"
 11#include "debug.h"
 12#include "parse-events.h"
 13#include "util/mmap.h"
 14#include <errno.h>
 15#include <linux/string.h>
 16
 17#define NR_ITERS 111
 18
 19static void testcase(void)
 20{
 21	int i;
 22
 23	for (i = 0; i < NR_ITERS; i++) {
 24		char proc_name[15];
 25
 26		snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);
 27		prctl(PR_SET_NAME, proc_name);
 28	}
 29}
 30
 31static int count_samples(struct evlist *evlist, int *sample_count,
 32			 int *comm_count)
 33{
 34	int i;
 35
 36	for (i = 0; i < evlist->core.nr_mmaps; i++) {
 37		struct mmap *map = &evlist->overwrite_mmap[i];
 38		union perf_event *event;
 39
 40		perf_mmap__read_init(map);
 41		while ((event = perf_mmap__read_event(map)) != NULL) {
 42			const u32 type = event->header.type;
 43
 44			switch (type) {
 45			case PERF_RECORD_SAMPLE:
 46				(*sample_count)++;
 47				break;
 48			case PERF_RECORD_COMM:
 49				(*comm_count)++;
 50				break;
 51			default:
 52				pr_err("Unexpected record of type %d\n", type);
 53				return TEST_FAIL;
 54			}
 55		}
 56		perf_mmap__read_done(map);
 57	}
 58	return TEST_OK;
 59}
 60
 61static int do_test(struct evlist *evlist, int mmap_pages,
 62		   int *sample_count, int *comm_count)
 63{
 64	int err;
 65	char sbuf[STRERR_BUFSIZE];
 66
 67	err = evlist__mmap(evlist, mmap_pages);
 68	if (err < 0) {
 69		pr_debug("evlist__mmap: %s\n",
 70			 str_error_r(errno, sbuf, sizeof(sbuf)));
 71		return TEST_FAIL;
 72	}
 73
 74	evlist__enable(evlist);
 75	testcase();
 76	evlist__disable(evlist);
 77
 78	err = count_samples(evlist, sample_count, comm_count);
 79	evlist__munmap(evlist);
 80	return err;
 81}
 82
 83
 84int test__backward_ring_buffer(struct test *test __maybe_unused, int subtest __maybe_unused)
 85{
 86	int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
 87	char pid[16], sbuf[STRERR_BUFSIZE];
 88	struct evlist *evlist;
 89	struct evsel *evsel __maybe_unused;
 90	struct parse_events_error parse_error;
 91	struct record_opts opts = {
 92		.target = {
 93			.uid = UINT_MAX,
 94			.uses_mmap = true,
 95		},
 96		.freq	      = 0,
 97		.mmap_pages   = 256,
 98		.default_interval = 1,
 99	};
100
101	snprintf(pid, sizeof(pid), "%d", getpid());
102	pid[sizeof(pid) - 1] = '\0';
103	opts.target.tid = opts.target.pid = pid;
104
105	evlist = evlist__new();
106	if (!evlist) {
107		pr_debug("Not enough memory to create evlist\n");
108		return TEST_FAIL;
109	}
110
111	err = perf_evlist__create_maps(evlist, &opts.target);
112	if (err < 0) {
113		pr_debug("Not enough memory to create thread/cpu maps\n");
114		goto out_delete_evlist;
115	}
116
117	bzero(&parse_error, sizeof(parse_error));
118	/*
119	 * Set backward bit, ring buffer should be writing from end. Record
120	 * it in aux evlist
121	 */
122	err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
123	if (err) {
124		pr_debug("Failed to parse tracepoint event, try use root\n");
125		ret = TEST_SKIP;
126		goto out_delete_evlist;
127	}
128
129	perf_evlist__config(evlist, &opts, NULL);
130
131	err = evlist__open(evlist);
132	if (err < 0) {
133		pr_debug("perf_evlist__open: %s\n",
134			 str_error_r(errno, sbuf, sizeof(sbuf)));
135		goto out_delete_evlist;
136	}
137
138	ret = TEST_FAIL;
139	err = do_test(evlist, opts.mmap_pages, &sample_count,
140		      &comm_count);
141	if (err != TEST_OK)
142		goto out_delete_evlist;
143
144	if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
145		pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
146		       sample_count, comm_count);
147		goto out_delete_evlist;
148	}
149
150	err = do_test(evlist, 1, &sample_count, &comm_count);
151	if (err != TEST_OK)
152		goto out_delete_evlist;
153
154	ret = TEST_OK;
155out_delete_evlist:
156	evlist__delete(evlist);
157	return ret;
158}