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authorPaul Mackerras <paulus@samba.org>2009-08-07 16:59:45 +1000
committerIngo Molnar <mingo@elte.hu>2009-08-09 12:54:37 +0200
commitf36a1a133a947973efb8e6a1fbdcc23e4a011437 (patch)
treec635e0a3a8329aac348c2e861f91347abe59792f
parentb26bc5a7f81474937e427b0c855eabee5ad56f89 (diff)
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>
-rw-r--r--arch/powerpc/kernel/perf_counter.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c
index 809fdf94b95..70e1f57f7dd 100644
--- a/arch/powerpc/kernel/perf_counter.c
+++ b/arch/powerpc/kernel/perf_counter.c
@@ -518,6 +518,8 @@ void hw_perf_disable(void)
struct cpu_hw_counters *cpuhw;
unsigned long flags;
+ if (!ppmu)
+ return;
local_irq_save(flags);
cpuhw = &__get_cpu_var(cpu_hw_counters);
@@ -572,6 +574,8 @@ void hw_perf_enable(void)
int n_lim;
int idx;
+ if (!ppmu)
+ return;
local_irq_save(flags);
cpuhw = &__get_cpu_var(cpu_hw_counters);
if (!cpuhw->disabled) {
@@ -737,6 +741,8 @@ int hw_perf_group_sched_in(struct perf_counter *group_leader,
long i, n, n0;
struct perf_counter *sub;
+ if (!ppmu)
+ return 0;
cpuhw = &__get_cpu_var(cpu_hw_counters);
n0 = cpuhw->n_counters;
n = collect_events(group_leader, ppmu->n_counter - n0,
@@ -1281,6 +1287,8 @@ void hw_perf_counter_setup(int cpu)
{
struct cpu_hw_counters *cpuhw = &per_cpu(cpu_hw_counters, cpu);
+ if (!ppmu)
+ return;
memset(cpuhw, 0, sizeof(*cpuhw));
cpuhw->mmcr[0] = MMCR0_FC;
}