linux-kernel - [PATCH v1 11/12] x86, alternative: Use alternative_2 in rdtsc

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Date:	Tue,  3 Feb 2015 19:16:29 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	X86 ML <x86@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Richard Weinberger <richard@....at>
Subject: [PATCH v1 11/12] x86, alternative: Use alternative_2 in rdtsc_barrier

From: Borislav Petkov <bp@...e.de>

... now that we have it.

Cc: Richard Weinberger <richard@....at>
Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/include/asm/barrier.h | 6 ++----
 arch/x86/um/asm/barrier.h      | 4 ++--
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 2ab1eb33106e..959e45b81fe2 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -95,13 +95,11 @@ do {									\
  * Stop RDTSC speculation. This is needed when you need to use RDTSC
  * (or get_cycles or vread that possibly accesses the TSC) in a defined
  * code region.
- *
- * (Could use an alternative three way for this if there was one.)
  */
 static __always_inline void rdtsc_barrier(void)
 {
-	alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
-	alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
+	alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC,
+			  "lfence", X86_FEATURE_LFENCE_RDTSC);
 }
 
 #endif /* _ASM_X86_BARRIER_H */
diff --git a/arch/x86/um/asm/barrier.h b/arch/x86/um/asm/barrier.h
index 2d7d9a1f5b53..8ffd2146fa6a 100644
--- a/arch/x86/um/asm/barrier.h
+++ b/arch/x86/um/asm/barrier.h
@@ -64,8 +64,8 @@
  */
 static inline void rdtsc_barrier(void)
 {
-	alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
-	alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
+	alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC,
+			  "lfence", X86_FEATURE_LFENCE_RDTSC);
 }
 
 #endif
-- 
2.2.0.33.gc18b867

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