linux-kernel - [PATCH] mtrr: fix PGE mask

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Message-ID: <464E7EFC.5030608@didntduck.org>
Date:	Sat, 19 May 2007 00:37:16 -0400
From:	Brian Gerst <bgerst@...ntduck.org>
To:	Andi Kleen <ak@...e.de>
CC:	lkml <linux-kernel@...r.kernel.org>
Subject: [PATCH] mtrr: fix PGE mask

cr4 is a 32-bit register, so casting the mask to an unsigned char is wrong,
as it clears more than the PGE bit.

Signed-off-by: Brian Gerst <bgerst@...ntduck.org>
---
 arch/i386/kernel/cpu/mtrr/cyrix.c |    2 +-
 arch/i386/kernel/cpu/mtrr/state.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/i386/kernel/cpu/mtrr/cyrix.c b/arch/i386/kernel/cpu/mtrr/cyrix.c
index 0737a59..9edf562 100644
--- a/arch/i386/kernel/cpu/mtrr/cyrix.c
+++ b/arch/i386/kernel/cpu/mtrr/cyrix.c
@@ -136,7 +136,7 @@ static void prepare_set(void)
 	/*  Save value of CR4 and clear Page Global Enable (bit 7)  */
 	if ( cpu_has_pge ) {
 		cr4 = read_cr4();
-		write_cr4(cr4 & (unsigned char) ~(1 << 7));
+		write_cr4(cr4 & ~X86_CR4_PGE);
 	}
 
 	/*  Disable and flush caches. Note that wbinvd flushes the TLBs as
diff --git a/arch/i386/kernel/cpu/mtrr/state.c b/arch/i386/kernel/cpu/mtrr/state.c
index f62ecd1..7b39a2f 100644
--- a/arch/i386/kernel/cpu/mtrr/state.c
+++ b/arch/i386/kernel/cpu/mtrr/state.c
@@ -19,7 +19,7 @@ void set_mtrr_prepare_save(struct set_mtrr_context *ctxt)
 		/*  Save value of CR4 and clear Page Global Enable (bit 7)  */
 		if ( cpu_has_pge ) {
 			ctxt->cr4val = read_cr4();
-			write_cr4(ctxt->cr4val & (unsigned char) ~(1 << 7));
+			write_cr4(ctxt->cr4val & ~X86_CR4_PGE);
 		}
 
 		/*  Disable and flush caches. Note that wbinvd flushes the TLBs as
-- 
1.5.2.rc3.39.gaf9b



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