linux-kernel - [PATCH] perf,x86: Fix Userspace RDPMC switch

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Date:	Wed, 5 Feb 2014 11:28:15 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	junk@...af.co.uk
Cc:	fweisbec@...il.com, Ingo Molnar <mingo@...nel.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] perf,x86: Fix Userspace RDPMC switch

Subject: perf,x86: Fix Userspace RDPMC switch
From: Peter Zijlstra <peterz@...radead.org>
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@...il.com
Reported-by: Mark Davies <junk@...af.co.uk>
Suggested-by: Mark Davies <junk@...af.co.uk>
Signed-off-by: Peter Zijlstra <peterz@...radead.org>
---
 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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