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
16static 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 */
40int 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);
125out:
126	evlist__delete(evlist);
127	return err;
128}
129