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perf_counter: powerpc: initialize cpuhw pointer before use 

Commit 9e35ad38 ("perf_counter: Rework the perf counter
disable/enable") added code to the powerpc hw_perf_enable (renamed
from hw_perf_restore) to test cpuhw->disabled and return immediately
if it is not set (i.e. if the PMU is already enabled).

Unfortunately the test got added before cpuhw was initialized,
resulting in an oops the first time hw_perf_enable got called.
This fixes it by moving the initialization of cpuhw to before
cpuhw->disabled is tested.

[ Impact: fix oops-causing bug on powerpc ]

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <18960.56772.869734.304631@drongo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul Mackerras 2009-05-18 14:02:12 +10:00 committed by Ingo Molnar
parent dc3f81b129
commit c0daaf3f1f
1 changed files with 1 additions and 2 deletions
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3
arch/powerpc/kernel/perf_counter.c
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@ -450,12 +450,11 @@ void hw_perf_enable(void)
int idx;
local_irq_save(flags);
cpuhw = &__get_cpu_var(cpu_hw_counters);
if (!cpuhw->disabled) {
local_irq_restore(flags);
return;
}
cpuhw = &__get_cpu_var(cpu_hw_counters);
cpuhw->disabled = 0;
/*