linux-kernel - [PATCH] drop unneeded variable in amd_apic_timer

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Date:	Tue, 7 Aug 2007 20:53:21 -0400 (EDT)
From:	Cal Peake <cp@...olutedigital.net>
To:	Andi Kleen <andi@...stfloor.org>
cc:	Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH] drop unneeded variable in amd_apic_timer_broken

On Wed, 8 Aug 2007, Andi Kleen wrote:

> Not sure why the MSR varies between cores though.

Yeah that boggled me too.

> It's better to just make it a global instead.

Haven't gotten to figuring out how to do *that* yet... but here's a 
cleanup for the detection function:

From: Cal Peake <cp@...olutedigital.net>

We only care about the lower 32-bits when reading the Interrupt Pending 
Message Register so drop the 'hi' variable and use rdmsrl() instead.

Signed-off-by: Cal Peake <cp@...olutedigital.net>

--- ./arch/i386/kernel/cpu/amd.c~orig	2007-08-07 20:22:26.000000000 -0400
+++ ./arch/i386/kernel/cpu/amd.c	2007-08-07 20:23:22.000000000 -0400
@@ -34,7 +34,7 @@ __asm__(".align 4\nvide: ret");
 /* AMD systems with C1E don't have a working lAPIC timer. Check for that. */
 static __cpuinit int amd_apic_timer_broken(void)
 {
-	u32 lo, hi;
+	u32 msr;
 	u32 eax = cpuid_eax(CPUID_PROCESSOR_SIGNATURE);
 	switch (eax & CPUID_XFAM) {
 	case CPUID_XFAM_K8:
@@ -42,8 +42,8 @@ static __cpuinit int amd_apic_timer_brok
 			break;
 	case CPUID_XFAM_10H:
 	case CPUID_XFAM_11H:
-		rdmsr(MSR_K8_ENABLE_C1E, lo, hi);
-		if (lo & ENABLE_C1E_MASK)
+		rdmsrl(MSR_K8_ENABLE_C1E, msr);
+		if (msr & ENABLE_C1E_MASK)
 			return 1;
                 break;
         default:
-
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