linux-kernel - [tip:x86/urgent] x86, mtrr: Fix a type overflow in range_to

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Date:	Wed, 30 May 2012 16:22:50 -0700
From:	"tip-bot for zhenzhong.duan" <zhenzhong.duan@...cle.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	zhenzhong.duan@...cle.com, tglx@...utronix.de
Subject: [tip:x86/urgent] x86, mtrr:
  Fix a type overflow in range_to_mtrr func

Commit-ID:  2da06af8106f8f35318bb084baf8448797ef058a
Gitweb:     http://git.kernel.org/tip/2da06af8106f8f35318bb084baf8448797ef058a
Author:     zhenzhong.duan <zhenzhong.duan@...cle.com>
AuthorDate: Wed, 30 May 2012 12:52:15 +0800
Committer:  H. Peter Anvin <hpa@...or.com>
CommitDate: Wed, 30 May 2012 14:37:00 -0700

x86, mtrr: Fix a type overflow in range_to_mtrr func

When boot on sun G5+ with 4T mem, see an overflow in mtrr cleanup as below.

*BAD*gran_size: 2G      chunk_size: 2G  num_reg: 10     lose cover RAM:
-18014398505283592M

This is because 1<<31 sign extended. Use an unsigned long constant to
fix it.  Useful for mem larger than or equal to 4T.

-v2: Use 64bit constant instead of explicit type conversion as suggested
by Yinghai. Description updated too.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
Link: http://lkml.kernel.org/r/4FC5A77F.6060505@oracle.com
Signed-off-by: H. Peter Anvin <hpa@...or.com>
---
 arch/x86/kernel/cpu/mtrr/cleanup.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
index ac140c7..bdda2e6 100644
--- a/arch/x86/kernel/cpu/mtrr/cleanup.c
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -266,7 +266,7 @@ range_to_mtrr(unsigned int reg, unsigned long range_startk,
 		if (align > max_align)
 			align = max_align;
 
-		sizek = 1 << align;
+		sizek = 1UL << align;
 		if (debug_print) {
 			char start_factor = 'K', size_factor = 'K';
 			unsigned long start_base, size_base;
--
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