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https://github.com/torvalds/linux
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e1e455f4f4
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>
93 lines
1.7 KiB
C
93 lines
1.7 KiB
C
#include <sched.h>
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#include "util.h"
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#include "../perf.h"
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#include "cloexec.h"
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#include "asm/bug.h"
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#include "debug.h"
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static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
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int __weak sched_getcpu(void)
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{
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errno = ENOSYS;
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return -1;
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}
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static int perf_flag_probe(void)
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{
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/* use 'safest' configuration as used in perf_evsel__fallback() */
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struct perf_event_attr attr = {
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.type = PERF_TYPE_SOFTWARE,
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.config = PERF_COUNT_SW_CPU_CLOCK,
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.exclude_kernel = 1,
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};
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int fd;
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int err;
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int cpu;
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pid_t pid = -1;
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char sbuf[STRERR_BUFSIZE];
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cpu = sched_getcpu();
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if (cpu < 0)
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cpu = 0;
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/*
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* Using -1 for the pid is a workaround to avoid gratuitous jump label
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* changes.
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*/
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while (1) {
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/* check cloexec flag */
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fd = sys_perf_event_open(&attr, pid, cpu, -1,
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PERF_FLAG_FD_CLOEXEC);
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if (fd < 0 && pid == -1 && errno == EACCES) {
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pid = 0;
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continue;
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}
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break;
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}
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err = errno;
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if (fd >= 0) {
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close(fd);
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return 1;
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}
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WARN_ONCE(err != EINVAL && err != EBUSY,
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"perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
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err, strerror_r(err, sbuf, sizeof(sbuf)));
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/* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
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while (1) {
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fd = sys_perf_event_open(&attr, pid, cpu, -1, 0);
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if (fd < 0 && pid == -1 && errno == EACCES) {
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pid = 0;
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continue;
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}
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break;
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}
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err = errno;
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if (fd >= 0)
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close(fd);
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if (WARN_ONCE(fd < 0 && err != EBUSY,
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"perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
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err, strerror_r(err, sbuf, sizeof(sbuf))))
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return -1;
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return 0;
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}
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unsigned long perf_event_open_cloexec_flag(void)
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{
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static bool probed;
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if (!probed) {
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if (perf_flag_probe() <= 0)
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flag = 0;
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probed = true;
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}
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return flag;
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}
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