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perf/abi: Change the errno for sampling event not supported in hardware 

Change the return code for sampling event not supported from -ENOTSUPP
to -EOPNOTSUPP.

This allows userspace to identify this case specifically, instead of
printing the catch-all error message it did previously.

Technically this is an ABI change, but we think we can get away
with it.

Old behavior:
 -------
 | # perf record ls
 | Error:
 | The sys_perf_event_open() syscall returned with 524 (Unknown error 524)
 | for event (cycles:ppp).
 | /bin/dmesg may provide additional information.
 | No CONFIG_PERF_EVENTS=y kernel support configured?

New behavior:
 -------
 | # perf record ls
 | Error:
 | PMU Hardware doesn't support sampling/overflow-interrupts.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <acme@redhat.com>
Cc: <linux-snps-arc@lists.infradead.org>
Cc: <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Link: http://lkml.kernel.org/r/1462786660-2900-3-git-send-email-vgupta@synopsys.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Vineet Gupta 2016-05-09 15:07:40 +05:30 committed by Ingo Molnar
parent a54fa07930
commit a1396555ab
1 changed files with 1 additions and 1 deletions
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2
kernel/events/core.c
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@ -9309,7 +9309,7 @@ SYSCALL_DEFINE5(perf_event_open,
if (is_sampling_event(event)) { if (is_sampling_event(event)) {
if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
err = -ENOTSUPP; err = -EOPNOTSUPP;
goto err_alloc; goto err_alloc;
} }
} }