linux_dsm_epyc7002/tools/perf/util/cloexec.c
Vinson Lee e1e455f4f4 perf tools: Work around lack of sched_getcpu in glibc < 2.6.
This patch fixes this build error with glibc < 2.6.

  CC       util/cloexec.o
cc1: warnings being treated as errors
util/cloexec.c: In function ‘perf_flag_probe’:
util/cloexec.c:24: error: implicit declaration of function
‘sched_getcpu’
util/cloexec.c:24: error: nested extern declaration of ‘sched_getcpu’
make: *** [util/cloexec.o] Error 1

Signed-off-by: Vinson Lee <vlee@twitter.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Yann Droneaud <ydroneaud@opteya.com>
Cc: stable@vger.kernel.org # 3.18+
Link: http://lkml.kernel.org/r/1427137761-16119-1-git-send-email-vlee@twopensource.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 12:08:07 -03:00

93 lines
1.7 KiB
C

#include <sched.h>
#include "util.h"
#include "../perf.h"
#include "cloexec.h"
#include "asm/bug.h"
#include "debug.h"
static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
int __weak sched_getcpu(void)
{
errno = ENOSYS;
return -1;
}
static int perf_flag_probe(void)
{
/* use 'safest' configuration as used in perf_evsel__fallback() */
struct perf_event_attr attr = {
.type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_CPU_CLOCK,
.exclude_kernel = 1,
};
int fd;
int err;
int cpu;
pid_t pid = -1;
char sbuf[STRERR_BUFSIZE];
cpu = sched_getcpu();
if (cpu < 0)
cpu = 0;
/*
* Using -1 for the pid is a workaround to avoid gratuitous jump label
* changes.
*/
while (1) {
/* check cloexec flag */
fd = sys_perf_event_open(&attr, pid, cpu, -1,
PERF_FLAG_FD_CLOEXEC);
if (fd < 0 && pid == -1 && errno == EACCES) {
pid = 0;
continue;
}
break;
}
err = errno;
if (fd >= 0) {
close(fd);
return 1;
}
WARN_ONCE(err != EINVAL && err != EBUSY,
"perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
err, strerror_r(err, sbuf, sizeof(sbuf)));
/* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
while (1) {
fd = sys_perf_event_open(&attr, pid, cpu, -1, 0);
if (fd < 0 && pid == -1 && errno == EACCES) {
pid = 0;
continue;
}
break;
}
err = errno;
if (fd >= 0)
close(fd);
if (WARN_ONCE(fd < 0 && err != EBUSY,
"perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
err, strerror_r(err, sbuf, sizeof(sbuf))))
return -1;
return 0;
}
unsigned long perf_event_open_cloexec_flag(void)
{
static bool probed;
if (!probed) {
if (perf_flag_probe() <= 0)
flag = 0;
probed = true;
}
return flag;
}