perf_counter/powerpc: Fix oops on cpus without perf_counter hardware support
authorPaul Mackerras <paulus@samba.org>
Fri, 7 Aug 2009 06:59:45 +0000 (16:59 +1000)
committerIngo Molnar <mingo@elte.hu>
Sun, 9 Aug 2009 10:54:37 +0000 (12:54 +0200)
commitf36a1a133a947973efb8e6a1fbdcc23e4a011437
treec635e0a3a8329aac348c2e861f91347abe59792f
parentb26bc5a7f81474937e427b0c855eabee5ad56f89
perf_counter/powerpc: Fix oops on cpus without perf_counter hardware support

If we have the powerpc perf_counter backend compiled in, but
the cpu we are running on is one where we don't support the
PMU, we currently oops in hw_perf_group_sched_in if we try to
use any counters, because ppmu is NULL in that case, and we
unconditionally dereference ppmu.

This fixes the problem by adding a check if ppmu is NULL at the
beginning of hw_perf_group_sched_in, and also at the beginning
of the other functions that get called from the perf_counter
core, i.e. hw_perf_disable, hw_perf_enable, and
hw_perf_counter_setup.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: benh@kernel.crashing.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/powerpc/kernel/perf_counter.c