From 2b9ff0db19b5e2c77000b7201525f9c3d6e8328d Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Sun, 14 Dec 2008 18:36:30 +0100
Subject: [PATCH] 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>
---
arch/x86/kernel/cpu/perf_counter.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 5afae13d8d59..6d30f603b62c 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -157,6 +157,9 @@ 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);
}
@@ -164,14 +167,21 @@ 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);
--
2.34.1