perfcounters: fix non-intel-perfmon CPUs

Do not write MSR_CORE_PERF_GLOBAL_CTRL on CPUs where it does not exist. Signed-off-by: Ingo Molnar <mingo@elte.hu>
git-mirror · Dec 14, 2008 · 2b9ff0d · 2b9ff0d
1 parent e06c61a
commit 2b9ff0d
Showing 1 changed file with 10 additions and 0 deletions.
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
@@ -157,21 +157,31 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
 
 void hw_perf_enable_all(void)
 {
+	if (unlikely(!perf_counters_initialized))
+		return;
+
 	wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, perf_counter_mask, 0);
 }
 
 u64 hw_perf_save_disable(void)
 {
 	u64 ctrl;
 
+	if (unlikely(!perf_counters_initialized))
+		return 0;
+
 	rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
 	wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0);
+
 	return ctrl;
 }
 EXPORT_SYMBOL_GPL(hw_perf_save_disable);
 
 void hw_perf_restore(u64 ctrl)
 {
+	if (unlikely(!perf_counters_initialized))
+		return;
+
 	wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, ctrl, 0);
 }
 EXPORT_SYMBOL_GPL(hw_perf_restore);