Commit | Line | Data |
---|---|---|
57480d2c YD |
1 | #include "util.h" |
2 | #include "../perf.h" | |
3 | #include "cloexec.h" | |
4 | #include "asm/bug.h" | |
5 | ||
6 | static unsigned long flag = PERF_FLAG_FD_CLOEXEC; | |
7 | ||
8 | static int perf_flag_probe(void) | |
9 | { | |
10 | /* use 'safest' configuration as used in perf_evsel__fallback() */ | |
11 | struct perf_event_attr attr = { | |
038fa0b9 | 12 | .type = PERF_TYPE_SOFTWARE, |
57480d2c YD |
13 | .config = PERF_COUNT_SW_CPU_CLOCK, |
14 | }; | |
15 | int fd; | |
16 | int err; | |
17 | ||
18 | /* check cloexec flag */ | |
8578b891 | 19 | fd = sys_perf_event_open(&attr, 0, -1, -1, |
57480d2c YD |
20 | PERF_FLAG_FD_CLOEXEC); |
21 | err = errno; | |
22 | ||
23 | if (fd >= 0) { | |
24 | close(fd); | |
25 | return 1; | |
26 | } | |
27 | ||
63914aca | 28 | WARN_ONCE(err != EINVAL && err != EBUSY, |
57480d2c YD |
29 | "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", |
30 | err, strerror(err)); | |
31 | ||
32 | /* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */ | |
8578b891 | 33 | fd = sys_perf_event_open(&attr, 0, -1, -1, 0); |
57480d2c YD |
34 | err = errno; |
35 | ||
63914aca | 36 | if (WARN_ONCE(fd < 0 && err != EBUSY, |
57480d2c YD |
37 | "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", |
38 | err, strerror(err))) | |
39 | return -1; | |
40 | ||
41 | close(fd); | |
42 | ||
43 | return 0; | |
44 | } | |
45 | ||
46 | unsigned long perf_event_open_cloexec_flag(void) | |
47 | { | |
48 | static bool probed; | |
49 | ||
50 | if (!probed) { | |
51 | if (perf_flag_probe() <= 0) | |
52 | flag = 0; | |
53 | probed = true; | |
54 | } | |
55 | ||
56 | return flag; | |
57 | } |