[PATCH] perf,x86: Fix Userspace RDPMC switch

From: Peter Zijlstra
Date: Wed Feb 05 2014 - 05:28:26 EST


Subject: perf,x86: Fix Userspace RDPMC switch
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Wed Feb 5 11:19:56 CET 2014

The current code forgets to change the CR4 state on the current CPU.
User on_each_cpu() instead of smp_call_function().

Cc: fweisbec@xxxxxxxxx
Reported-by: Mark Davies <junk@xxxxxxxxxxx>
Suggested-by: Mark Davies <junk@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1826,7 +1826,7 @@ static ssize_t set_attr_rdpmc(struct dev

if (!!val != !!x86_pmu.attr_rdpmc) {
x86_pmu.attr_rdpmc = !!val;
- smp_call_function(change_rdpmc, (void *)val, 1);
+ on_each_cpu(change_rdpmc, (void *)val, 1);
}

return count;
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