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_suite *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("evlist__new failed\n");
56 return TEST_FAIL;
57 }
58
59 ret = parse_event(evlist, "intel_cqm/llc_occupancy/");
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
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