linux-kernel - [patch] x86: lfence fix

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Date:	Tue, 15 Jan 2008 22:03:21 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	Jeremy Fitzhardinge <jeremy@...p.org>, tglx@...utronix.de,
	linux-kernel@...r.kernel.org
Subject: [patch] x86: lfence fix


* Andi Kleen <andi@...stfloor.org> wrote:

> I just tested x86.git and then x86.git + patch you send (+ build fixes 
> in both cases), none of your patchkits. If you want me to test some 
> other patchkit please point me to it.
> 
> The problem happens with plain git-x86 (+ build fixes) and also with 
> git-x86 + your patch.

i was held up from debugging your problem by a bug introduced by you 
into x86.git ;-) See the fix below.

	Ingo

----------------------------->
Subject: x86: lfence fix
From: Ingo Molnar <mingo@...e.hu>

LFENCE is available on XMM2 or higher Intel CPUs - not XMM or higher...

this caused boot failures on pre-XMM2 CPUs.

Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/kernel/cpu/intel.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-x86.q/arch/x86/kernel/cpu/intel.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/cpu/intel.c
+++ linux-x86.q/arch/x86/kernel/cpu/intel.c
@@ -206,7 +206,7 @@ static void __cpuinit init_intel(struct 
 	}
 #endif
 
-	if (cpu_has_xmm)
+	if (cpu_has_xmm2)
 		set_bit(X86_FEATURE_LFENCE_RDTSC, c->x86_capability);
 	if (c->x86 == 15) {
 		set_bit(X86_FEATURE_P4, c->x86_capability);
--
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