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 #define __maybe_unused __attribute__((__unused__))
21
22 static int sigio_count;
23
24 static void handle_sigio(int signum __maybe_unused,
25 siginfo_t *oh __maybe_unused,
26 void *uc __maybe_unused)
27 {
28 ++sigio_count;
29 }
30
31 static void do_child(void)
32 {
33 raise(SIGSTOP);
34
35 for (int i = 0; i < 20; ++i)
36 sleep(1);
37
38 raise(SIGSTOP);
39
40 exit(0);
41 }
42
43 TEST(watermark_signal)
44 {
45 struct perf_event_attr attr;
46 struct perf_event_mmap_page *p = NULL;
47 struct sigaction previous_sigio, sigio = { 0 };
48 pid_t child = -1;
49 int child_status;
50 int fd = -1;
51 long page_size = sysconf(_SC_PAGE_SIZE);
52
53 sigio.sa_sigaction = handle_sigio;
54 EXPECT_EQ(sigaction(SIGIO, &sigio, &previous_sigio), 0);
55
56 memset(&attr, 0, sizeof(attr));
57 attr.size = sizeof(attr);
58 attr.type = PERF_TYPE_SOFTWARE;
59 attr.config = PERF_COUNT_SW_DUMMY;
60 attr.sample_period = 1;
61 attr.disabled = 1;
62 attr.watermark = 1;
63 attr.context_switch = 1;
64 attr.wakeup_watermark = 1;
65
66 child = fork();
67 EXPECT_GE(child, 0);
68 if (child == 0)
69 do_child();
70 else if (child < 0) {
71 perror("fork()");
72 goto cleanup;
73 }
74
75 if (waitpid(child, &child_status, WSTOPPED) != child ||
76 !(WIFSTOPPED(child_status) && WSTOPSIG(child_status) == SIGSTOP)) {
77 fprintf(stderr,
78 "failed to sycnhronize with child errno=%d status=%x\n",
79 errno,
80 child_status);
81 goto cleanup;
82 }
83
84 fd = syscall(__NR_perf_event_open, &attr, child, -1, -1,
85 PERF_FLAG_FD_CLOEXEC);
86 if (fd < 0) {
87 fprintf(stderr, "failed opening event %llx\n", attr.config);
88 goto cleanup;
89 }
90
91 if (fcntl(fd, F_SETFL, FASYNC)) {
92 perror("F_SETFL FASYNC");
93 goto cleanup;
94 }
95
96 if (fcntl(fd, F_SETOWN, getpid())) {
97 perror("F_SETOWN getpid()");
98 goto cleanup;
99 }
100
101 if (fcntl(fd, F_SETSIG, SIGIO)) {
102 perror("F_SETSIG SIGIO");
103 goto cleanup;
104 }
105
106 p = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
107 if (p == NULL) {
108 perror("mmap");
109 goto cleanup;
110 }
111
112 if (ioctl(fd, PERF_EVENT_IOC_ENABLE, 0)) {
113 perror("PERF_EVENT_IOC_ENABLE");
114 goto cleanup;
115 }
116
117 if (kill(child, SIGCONT) < 0) {
118 perror("SIGCONT");
119 goto cleanup;
120 }
121
122 if (waitpid(child, &child_status, WSTOPPED) != -1 || errno != EINTR)
123 fprintf(stderr,
124 "expected SIGIO to terminate wait errno=%d status=%x\n%d",
125 errno,
126 child_status,
127 sigio_count);
128
129 EXPECT_GE(sigio_count, 1);
130
131 cleanup:
132 if (p != NULL)
133 munmap(p, 2 * page_size);
134
135 if (fd >= 0)
136 close(fd);
137
138 if (child > 0) {
139 kill(child, SIGKILL);
140 waitpid(child, NULL, 0);
141 }
142
143 sigaction(SIGIO, &previous_sigio, NULL);
144 }
145
146 TEST_HARNESS_MAIN
147
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