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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vince Weaver <[email protected]>
Cc: Vineet Gupta <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f94f164b5054..5d48306879d5 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9309,7 +9309,7 @@ SYSCALL_DEFINE5(perf_event_open,
 
 	if (is_sampling_event(event)) {
 		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
-			err = -ENOTSUPP;
+			err = -EOPNOTSUPP;
 			goto err_alloc;
 		}
 	}