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

From: tip-bot for Borislav Petkov
Date: Tue Nov 24 2015 - 04:34:58 EST


Commit-ID: 679bcea857d72868e3431dde3a0e158bf0ed9119
Gitweb: http://git.kernel.org/tip/679bcea857d72868e3431dde3a0e158bf0ed9119
Author: Borislav Petkov <bp@xxxxxxx>
AuthorDate: Mon, 23 Nov 2015 11:12:26 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1448273546-2567-7-git-send-email-bp@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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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