1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3
4 #include <errno.h>
5 #include <fcntl.h>
6 #include <linux/perf_event.h>
7 #include <stddef.h>
8 #include <sched.h>
9 #include <signal.h>
10 #include <stdlib.h>
11 #include <string.h>
12 #include <sys/ioctl.h>
13 #include <sys/mman.h>
14 #include <sys/syscall.h>
15 #include <sys/wait.h>
16 #include <unistd.h>
17
18 #include "../kselftest_harness.h"
19
20 static int sigio_count;
21
handle_sigio(int signum __maybe_unused,siginfo_t * oh __maybe_unused,void * uc __maybe_unused)22 static void handle_sigio(int signum __maybe_unused,
23 siginfo_t *oh __maybe_unused,
24 void *uc __maybe_unused)
25 {
26 ++sigio_count;
27 }
28
do_child(void)29 static void do_child(void)
30 {
31 raise(SIGSTOP);
32
33 for (int i = 0; i < 20; ++i)
34 sleep(1);
35
36 raise(SIGSTOP);
37
38 exit(0);
39 }
40
TEST(watermark_signal)41 TEST(watermark_signal)
42 {
43 struct perf_event_attr attr;
44 struct perf_event_mmap_page *p = NULL;
45 struct sigaction previous_sigio, sigio = { 0 };
46 pid_t child = -1;
47 int child_status;
48 int fd = -1;
49 long page_size = sysconf(_SC_PAGE_SIZE);
50
51 sigio.sa_sigaction = handle_sigio;
52 EXPECT_EQ(sigaction(SIGIO, &sigio, &previous_sigio), 0);
53
54 memset(&attr, 0, sizeof(attr));
55 attr.size = sizeof(attr);
56 attr.type = PERF_TYPE_SOFTWARE;
57 attr.config = PERF_COUNT_SW_DUMMY;
58 attr.sample_period = 1;
59 attr.disabled = 1;
60 attr.watermark = 1;
61 attr.context_switch = 1;
62 attr.wakeup_watermark = 1;
63
64 child = fork();
65 EXPECT_GE(child, 0);
66 if (child == 0)
67 do_child();
68 else if (child < 0) {
69 perror("fork()");
70 goto cleanup;
71 }
72
73 if (waitpid(child, &child_status, WSTOPPED) != child ||
74 !(WIFSTOPPED(child_status) && WSTOPSIG(child_status) == SIGSTOP)) {
75 fprintf(stderr,
76 "failed to synchronize with child errno=%d status=%x\n",
77 errno,
78 child_status);
79 goto cleanup;
80 }
81
82 fd = syscall(__NR_perf_event_open, &attr, child, -1, -1,
83 PERF_FLAG_FD_CLOEXEC);
84 if (fd < 0) {
85 fprintf(stderr, "failed opening event %llx\n", attr.config);
86 goto cleanup;
87 }
88
89 if (fcntl(fd, F_SETFL, FASYNC)) {
90 perror("F_SETFL FASYNC");
91 goto cleanup;
92 }
93
94 if (fcntl(fd, F_SETOWN, getpid())) {
95 perror("F_SETOWN getpid()");
96 goto cleanup;
97 }
98
99 if (fcntl(fd, F_SETSIG, SIGIO)) {
100 perror("F_SETSIG SIGIO");
101 goto cleanup;
102 }
103
104 p = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
105 if (p == NULL) {
106 perror("mmap");
107 goto cleanup;
108 }
109
110 if (ioctl(fd, PERF_EVENT_IOC_ENABLE, 0)) {
111 perror("PERF_EVENT_IOC_ENABLE");
112 goto cleanup;
113 }
114
115 if (kill(child, SIGCONT) < 0) {
116 perror("SIGCONT");
117 goto cleanup;
118 }
119
120 if (waitpid(child, &child_status, WSTOPPED) != -1 || errno != EINTR)
121 fprintf(stderr,
122 "expected SIGIO to terminate wait errno=%d status=%x\n%d",
123 errno,
124 child_status,
125 sigio_count);
126
127 EXPECT_GE(sigio_count, 1);
128
129 cleanup:
130 if (p != NULL)
131 munmap(p, 2 * page_size);
132
133 if (fd >= 0)
134 close(fd);
135
136 if (child > 0) {
137 kill(child, SIGKILL);
138 waitpid(child, NULL, 0);
139 }
140
141 sigaction(SIGIO, &previous_sigio, NULL);
142 }
143
144 TEST_HARNESS_MAIN
145