On Fri, Oct 30, 2015 at 08:32:53PM +0100, Borislav Petkov wrote: > On Fri, Oct 30, 2015 at 12:26:42PM -0700, Andy Lutomirski wrote: > > Want to add that to the patch or make it another patch? > > Yeah, I'll make another one as it is going to document why we're > explicitly ANDing with 0xffffffffull.
--- >From 89bfdb82447fd5c9f5bd9753040a639364b0c9d2 Mon Sep 17 00:00:00 2001 From: Borislav Petkov <[email protected]> Date: Sat, 31 Oct 2015 12:40:48 +0100 Subject: [PATCH] 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. Signed-off-by: Borislav Petkov <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> --- 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 77d8b284e4a7..86133827c75c 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 */ -- 2.3.5 -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
