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 <errno.h> 13 14 #define NR_ITERS 111 15 16 static void testcase(void) 17 { 18 int i; 19 20 for (i = 0; i < NR_ITERS; i++) { 21 char proc_name[15]; 22 23 snprintf(proc_name, sizeof(proc_name), "p:%d\n", i); 24 prctl(PR_SET_NAME, proc_name); 25 } 26 } 27 28 static int count_samples(struct 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 58 static int do_test(struct 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 evlist__enable(evlist); 72 testcase(); 73 evlist__disable(evlist); 74 75 err = count_samples(evlist, sample_count, comm_count); 76 perf_evlist__munmap(evlist); 77 return err; 78 } 79 80 81 int 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 evlist *evlist; 86 struct 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 = 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 = 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; 152 out_delete_evlist: 153 evlist__delete(evlist); 154 return ret; 155 } 156