perf list: Fix checking for supported events on older kernels
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 b41f1cec91c37eeea6fdb15effbfa24ea0a5536b
 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 <9ec30cbe6866ea02e0164f8ba2bb9ead0052680e@umit.maine.edu>
Signed-off-by: Vince Weaver <b486a64568929e3535e394c7ca98794b49f6ab74@maine.edu>
Acked-by: Namhyung Kim <5c915a589b3ddf58cebf14bec41bcc143b37ac3c@kernel.org>
Cc: Chad Paradis <9ec30cbe6866ea02e0164f8ba2bb9ead0052680e@umit.maine.edu>
Cc: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@redhat.com>
Cc: Namhyung Kim <5c915a589b3ddf58cebf14bec41bcc143b37ac3c@kernel.org>
Cc: Paul Mackerras <19a0ba370c443ba08d20b5061586430ab449ee8c@samba.org>
Cc: Peter Zijlstra <645ca7d3a8d3d4f60557176cd361ea8351edc32b@chello.nl>
Link: c636d1003f91237ae1c9ca801298e4060fe456e7@vincent-weaver-1.um.maine.edu
Signed-off-by: Arnaldo Carvalho de Melo <293abb6b76d7791c0732cc517d38c4b5c734b87f@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs