linux-kernel - [PATCH] x86/msr: Make wrmsrl

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Date:	Thu,  4 Jun 2015 17:13:44 -0700
From:	Andy Lutomirski <luto@...nel.org>
To:	x86@...nel.org
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Borislav Petkov <bp@...en8.de>,
	Andy Lutomirski <luto@...nel.org>
Subject: [PATCH] x86/msr: Make wrmsrl_safe a function

The wrmsrl_safe macro performs invalid shifts if the value argument
is 32 bits.  This makes it unnecessarily awkward to write code that
puts an unsigned long into an MSR.

Convert it to a real inline function.

For inspiration, see 7c74d5b7b7b6 ("x86/asm/entry/64: Fix
MSR_IA32_SYSENTER_CS MSR value").

Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
 arch/x86/include/asm/msr.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index de36f22eb0b9..4c576877396c 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -205,8 +205,10 @@ do {                                                            \
 
 #endif	/* !CONFIG_PARAVIRT */
 
-#define wrmsrl_safe(msr, val) wrmsr_safe((msr), (u32)(val),		\
-					     (u32)((val) >> 32))
+static inline int wrmsrl_safe(unsigned msr, u64 val)
+{
+	return wrmsr_safe((msr), (u32)val,  (u32)(val >> 32));
+}
 
 #define write_tsc(low, high) wrmsr(MSR_IA32_TSC, (low), (high))
 
-- 
2.4.2

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