1 // SPDX-License-Identifier: GPL-2.0 2 #include "tests/tests.h" 3 #include "cloexec.h" 4 #include "debug.h" 5 #include "evlist.h" 6 #include "evsel.h" 7 #include "arch-tests.h" 8 #include <internal/lib.h> // page_size 9 10 #include <signal.h> 11 #include <sys/mman.h> 12 #include <sys/wait.h> 13 #include <errno.h> 14 #include <string.h> 15 16 static pid_t spawn(void) 17 { 18 pid_t pid; 19 20 pid = fork(); 21 if (pid) 22 return pid; 23 24 while(1) 25 sleep(5); 26 return 0; 27 } 28 29 /* 30 * Create an event group that contains both a sampled hardware 31 * (cpu-cycles) and software (intel_cqm/llc_occupancy/) event. We then 32 * wait for the hardware perf counter to overflow and generate a PMI, 33 * which triggers an event read for both of the events in the group. 34 * 35 * Since reading Intel CQM event counters requires sending SMP IPIs, the 36 * CQM pmu needs to handle the above situation gracefully, and return 37 * the last read counter value to avoid triggering a WARN_ON_ONCE() in 38 * smp_call_function_many() caused by sending IPIs from NMI context. 39 */ 40 int test__intel_cqm_count_nmi_context(struct test *test __maybe_unused, int subtest __maybe_unused) 41 { 42 struct evlist *evlist = NULL; 43 struct evsel *evsel = NULL; 44 struct perf_event_attr pe; 45 int i, fd[2], flag, ret; 46 size_t mmap_len; 47 void *event; 48 pid_t pid; 49 int err = TEST_FAIL; 50 51 flag = perf_event_open_cloexec_flag(); 52 53 evlist = evlist__new(); 54 if (!evlist) { 55 pr_debug("perf_evlist__new failed\n"); 56 return TEST_FAIL; 57 } 58 59 ret = parse_events(evlist, "intel_cqm/llc_occupancy/", NULL); 60 if (ret) { 61 pr_debug("parse_events failed, is \"intel_cqm/llc_occupancy/\" available?\n"); 62 err = TEST_SKIP; 63 goto out; 64 } 65 66 evsel = evlist__first(evlist); 67 if (!evsel) { 68 pr_debug("evlist__first failed\n"); 69 goto out; 70 } 71 72 memset(&pe, 0, sizeof(pe)); 73 pe.size = sizeof(pe); 74 75 pe.type = PERF_TYPE_HARDWARE; 76 pe.config = PERF_COUNT_HW_CPU_CYCLES; 77 pe.read_format = PERF_FORMAT_GROUP; 78 79 pe.sample_period = 128; 80 pe.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_READ; 81 82 pid = spawn(); 83 84 fd[0] = sys_perf_event_open(&pe, pid, -1, -1, flag); 85 if (fd[0] < 0) { 86 pr_debug("failed to open event\n"); 87 goto out; 88 } 89 90 memset(&pe, 0, sizeof(pe)); 91 pe.size = sizeof(pe); 92 93 pe.type = evsel->attr.type; 94 pe.config = evsel->attr.config; 95 96 fd[1] = sys_perf_event_open(&pe, pid, -1, fd[0], flag); 97 if (fd[1] < 0) { 98 pr_debug("failed to open event\n"); 99 goto out; 100 } 101 102 /* 103 * Pick a power-of-two number of pages + 1 for the meta-data 104 * page (struct perf_event_mmap_page). See tools/perf/design.txt. 105 */ 106 mmap_len = page_size * 65; 107 108 event = mmap(NULL, mmap_len, PROT_READ, MAP_SHARED, fd[0], 0); 109 if (event == (void *)(-1)) { 110 pr_debug("failed to mmap %d\n", errno); 111 goto out; 112 } 113 114 sleep(1); 115 116 err = TEST_OK; 117 118 munmap(event, mmap_len); 119 120 for (i = 0; i < 2; i++) 121 close(fd[i]); 122 123 kill(pid, SIGKILL); 124 wait(NULL); 125 out: 126 evlist__delete(evlist); 127 return err; 128 } 129