linux-kernel - [tip:x86/pti] x86/msr: Remove now unused definition of MFENCE

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Message-ID: <tip-eeab3eee2fa4a8e8eb52e2abf034f14f1d010e0d@git.kernel.org>
Date:   Sat, 6 Jan 2018 13:06:25 -0800
From:   tip-bot for Tom Lendacky <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     torvalds@...ux-foundation.org, tim.c.chen@...ux.intel.com,
        hpa@...or.com, linux-kernel@...r.kernel.org, tglx@...utronix.de,
        dwmw@...zon.co.uk, thomas.lendacky@....com, dave.hansen@...el.com,
        gregkh@...ux-foundation.org, pjt@...gle.com, peterz@...radead.org,
        mingo@...nel.org, bp@...en8.de
Subject: [tip:x86/pti] x86/msr: Remove now unused definition of MFENCE_RDTSC
 feature

Commit-ID:  eeab3eee2fa4a8e8eb52e2abf034f14f1d010e0d
Gitweb:     https://git.kernel.org/tip/eeab3eee2fa4a8e8eb52e2abf034f14f1d010e0d
Author:     Tom Lendacky <thomas.lendacky@....com>
AuthorDate: Fri, 5 Jan 2018 10:08:05 -0600
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Sat, 6 Jan 2018 21:57:41 +0100

x86/msr: Remove now unused definition of MFENCE_RDTSC feature

With the switch to using LFENCE_RDTSC on AMD platforms there is no longer
a need for the MFENCE_RDTSC feature.  Remove its usage and definition.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Borislav Petkov <bp@...en8.de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Tim Chen <tim.c.chen@...ux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@...ux-foundation.org>
Cc: David Woodhouse <dwmw@...zon.co.uk>
Cc: Paul Turner <pjt@...gle.com>
Cc: stable@...r.kernel.org
Link: https://lkml.kernel.org/r/20180105160805.23786.5177.stgit@tlendack-t1.amdoffice.net

---
 arch/x86/include/asm/cpufeatures.h | 2 +-
 arch/x86/include/asm/msr.h         | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 1641c2f..511d909 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -96,7 +96,7 @@
 #define X86_FEATURE_SYSCALL32		( 3*32+14) /* "" syscall in IA32 userspace */
 #define X86_FEATURE_SYSENTER32		( 3*32+15) /* "" sysenter in IA32 userspace */
 #define X86_FEATURE_REP_GOOD		( 3*32+16) /* REP microcode works well */
-#define X86_FEATURE_MFENCE_RDTSC	( 3*32+17) /* "" MFENCE synchronizes RDTSC */
+/* free, was: #define X86_FEATURE_MFENCE_RDTSC	( 3*32+17)  "" MFENCE synchronizes RDTSC */
 #define X86_FEATURE_LFENCE_RDTSC	( 3*32+18) /* "" LFENCE synchronizes RDTSC */
 #define X86_FEATURE_ACC_POWER		( 3*32+19) /* AMD Accumulated Power Mechanism */
 #define X86_FEATURE_NOPL		( 3*32+20) /* The NOPL (0F 1F) instructions */
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 07962f5..8d8d7ae 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -214,8 +214,7 @@ static __always_inline unsigned long long rdtsc_ordered(void)
 	 * that some other imaginary CPU is updating continuously with a
 	 * time stamp.
 	 */
-	alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC,
-			  "lfence", X86_FEATURE_LFENCE_RDTSC);
+	alternative("", "lfence", X86_FEATURE_LFENCE_RDTSC);
 	return rdtsc();
 }