mirror of
https://github.com/torvalds/linux
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8578b891ec
This reverts commit deaff8b659.
This commit makes CLOEXEC feature undetected for normal users,
because per-cpu events are priviledged.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20140728065844.GK6758@twins.programming.kicks-ass.net
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
58 lines
1.1 KiB
C
58 lines
1.1 KiB
C
#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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static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
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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_COUNT_SW_CPU_CLOCK,
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.config = PERF_COUNT_SW_CPU_CLOCK,
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};
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int fd;
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int err;
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/* check cloexec flag */
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fd = sys_perf_event_open(&attr, 0, -1, -1,
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PERF_FLAG_FD_CLOEXEC);
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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,
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"perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
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err, strerror(err));
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/* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
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fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
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err = errno;
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if (WARN_ONCE(fd < 0,
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"perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
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err, strerror(err)))
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return -1;
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close(fd);
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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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