perf list: Fix checking for supported events on older kernels
"perf list" listing of hardware events doesn't work on older ARM devices. The change enabling event detection: commit b41f1cec Author: Namhyung Kim <namhyung.kim@lge.com> Date: Tue Aug 27 11:41:53 2013 +0900 perf list: Skip unsupported events uses the following code in tools/perf/util/parse-events.c: struct perf_event_attr attr = { .type = type, .config = config, .disabled = 1, .exclude_kernel = 1, }; On ARM machines pre-dating the Cortex-A15 this doesn't work, as these machines don't support .exclude_kernel. So starting with 3.12 "perf list" does not report any hardware events at all on older machines (seen on Rasp-Pi, Pandaboard, Beagleboard, etc). This version of the patch makes changes suggested by Namhyung Kim to check for EACCESS and retry (instead of just dropping the exclude_kernel) so we can properly handle machines where /proc/sys/kernel/perf_event_paranoid is set to 2. Reported-by:Chad Paradis <chad.paradis@umit.maine.edu> Signed-off-by:
Vince Weaver <vincent.weaver@maine.edu> Acked-by:
Namhyung Kim <namhyung@kernel.org> Cc: Chad Paradis <chad.paradis@umit.maine.edu> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1312301536150.28814@vincent-weaver-1.um.maine.eduSigned-off-by:
Arnaldo Carvalho de Melo <acme@redhat.com>
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