linux-kernel - [tip:x86/cpu] x86/MSR: Chop off lower 32-bit value

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Date:	Tue, 24 Nov 2015 01:33:52 -0800
From:	tip-bot for Borislav Petkov <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, brgerst@...il.com,
	torvalds@...ux-foundation.org, luto@...capital.net,
	dvlasenk@...hat.com, peterz@...radead.org, hpa@...or.com,
	mingo@...nel.org, bp@...en8.de, tglx@...utronix.de, bp@...e.de,
	luto@...nel.org
Subject: [tip:x86/cpu] x86/MSR: Chop off lower 32-bit value

Commit-ID:  679bcea857d72868e3431dde3a0e158bf0ed9119
Gitweb:     http://git.kernel.org/tip/679bcea857d72868e3431dde3a0e158bf0ed9119
Author:     Borislav Petkov <bp@...e.de>
AuthorDate: Mon, 23 Nov 2015 11:12:26 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 24 Nov 2015 09:15:55 +0100

x86/MSR: Chop off lower 32-bit value

sparse complains that the cast truncates the high bits. But here
we really do know what we're doing and we need the lower 32 bits
only as the @low argument. So make that explicit.

Suggested-by: Andy Lutomirski <luto@...nel.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/1448273546-2567-7-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/msr.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 77d8b28..8613382 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -190,7 +190,7 @@ static inline void wrmsr(unsigned msr, unsigned low, unsigned high)
 
 static inline void wrmsrl(unsigned msr, u64 val)
 {
-	native_write_msr(msr, (u32)val, (u32)(val >> 32));
+	native_write_msr(msr, (u32)(val & 0xffffffffULL), (u32)(val >> 32));
 }
 
 /* wrmsr with exception handling */
--
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