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#include <perf/mmap.h>
 17
 18#define NR_ITERS 111
 19
 20static void testcase(void)
 21{
 22	int i;
 23
 24	for (i = 0; i < NR_ITERS; i++) {
 25		char proc_name[15];
 26
 27		snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);
 28		prctl(PR_SET_NAME, proc_name);
 29	}
 30}
 31
 32static int count_samples(struct evlist *evlist, int *sample_count,
 33			 int *comm_count)
 34{
 35	int i;
 36
 37	for (i = 0; i < evlist->core.nr_mmaps; i++) {
 38		struct mmap *map = &evlist->overwrite_mmap[i];
 39		union perf_event *event;
 40
 41		perf_mmap__read_init(&map->core);
 42		while ((event = perf_mmap__read_event(&map->core)) != NULL) {
 43			const u32 type = event->header.type;
 44
 45			switch (type) {
 46			case PERF_RECORD_SAMPLE:
 47				(*sample_count)++;
 48				break;
 49			case PERF_RECORD_COMM:
 50				(*comm_count)++;
 51				break;
 52			default:
 53				pr_err("Unexpected record of type %d\n", type);
 54				return TEST_FAIL;
 55			}
 56		}
 57		perf_mmap__read_done(&map->core);
 58	}
 59	return TEST_OK;
 60}
 61
 62static int do_test(struct evlist *evlist, int mmap_pages,
 63		   int *sample_count, int *comm_count)
 64{
 65	int err;
 66	char sbuf[STRERR_BUFSIZE];
 67
 68	err = evlist__mmap(evlist, mmap_pages);
 69	if (err < 0) {
 70		pr_debug("evlist__mmap: %s\n",
 71			 str_error_r(errno, sbuf, sizeof(sbuf)));
 72		return TEST_FAIL;
 73	}
 74
 75	evlist__enable(evlist);
 76	testcase();
 77	evlist__disable(evlist);
 78
 79	err = count_samples(evlist, sample_count, comm_count);
 80	evlist__munmap(evlist);
 81	return err;
 82}
 83
 84
 85static int test__backward_ring_buffer(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 86{
 87	int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
 88	char pid[16], sbuf[STRERR_BUFSIZE];
 89	struct evlist *evlist;
 90	struct evsel *evsel __maybe_unused;
 91	struct parse_events_error parse_error;
 92	struct record_opts opts = {
 93		.target = {
 94			.uid = UINT_MAX,
 95			.uses_mmap = true,
 96		},
 97		.freq	      = 0,
 98		.mmap_pages   = 256,
 99		.default_interval = 1,
100	};
101
102	snprintf(pid, sizeof(pid), "%d", getpid());
103	pid[sizeof(pid) - 1] = '\0';
104	opts.target.tid = opts.target.pid = pid;
105
106	evlist = evlist__new();
107	if (!evlist) {
108		pr_debug("Not enough memory to create evlist\n");
109		return TEST_FAIL;
110	}
111
112	err = evlist__create_maps(evlist, &opts.target);
113	if (err < 0) {
114		pr_debug("Not enough memory to create thread/cpu maps\n");
115		goto out_delete_evlist;
116	}
117
118	parse_events_error__init(&parse_error);
119	/*
120	 * Set backward bit, ring buffer should be writing from end. Record
121	 * it in aux evlist
122	 */
123	err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
124	parse_events_error__exit(&parse_error);
125	if (err) {
126		pr_debug("Failed to parse tracepoint event, try use root\n");
127		ret = TEST_SKIP;
128		goto out_delete_evlist;
129	}
130
131	evlist__config(evlist, &opts, NULL);
132
133	err = evlist__open(evlist);
134	if (err < 0) {
135		pr_debug("perf_evlist__open: %s\n",
136			 str_error_r(errno, sbuf, sizeof(sbuf)));
137		goto out_delete_evlist;
138	}
139
140	ret = TEST_FAIL;
141	err = do_test(evlist, opts.mmap_pages, &sample_count,
142		      &comm_count);
143	if (err != TEST_OK)
144		goto out_delete_evlist;
145
146	if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
147		pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
148		       sample_count, comm_count);
149		goto out_delete_evlist;
150	}
151
152	evlist__close(evlist);
153
154	err = evlist__open(evlist);
155	if (err < 0) {
156		pr_debug("perf_evlist__open: %s\n",
157			 str_error_r(errno, sbuf, sizeof(sbuf)));
158		goto out_delete_evlist;
159	}
160
161	err = do_test(evlist, 1, &sample_count, &comm_count);
162	if (err != TEST_OK)
163		goto out_delete_evlist;
164
165	ret = TEST_OK;
166out_delete_evlist:
167	evlist__delete(evlist);
168	return ret;
169}
170
171DEFINE_SUITE("Read backward ring buffer", backward_ring_buffer);