From: Tom Lendacky <thomas.lendacky@amd.com>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Dave Hansen <dave.hansen@intel.com>,
Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
Tim Chen <tim.c.chen@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linux-foundation.org>,
David Woodhouse <dwmw@amazon.co.uk>, Paul Turner <pjt@google.com>
Subject: [PATCH v1 3/3] x86/msr: Remove now unused definition of MFENCE_RDTSC feature
Date: Fri, 05 Jan 2018 10:08:05 -0600 [thread overview]
Message-ID: <20180105160805.23786.5177.stgit@tlendack-t1.amdoffice.net> (raw)
In-Reply-To: <20180105160736.23786.45026.stgit@tlendack-t1.amdoffice.net>
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@amd.com>
---
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 07cdd17..14ad778 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();
}
next prev parent reply other threads:[~2018-01-05 16:08 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-05 16:07 [PATCH v1 0/3] x86/cpu/AMD: Make LFENCE a serializing instruction on AMD Tom Lendacky
2018-01-05 16:07 ` [PATCH v1 1/3] x86/cpu/AMD: Make LFENCE a serializing instruction Tom Lendacky
2018-01-05 16:35 ` Brian Gerst
2018-01-05 16:36 ` Tom Lendacky
2018-01-06 21:05 ` [tip:x86/pti] " tip-bot for Tom Lendacky
2018-01-05 16:07 ` [PATCH v1 2/3] x86/cpu/AMD: Use LFENCE_RDTSC instead of MFENCE_RDTSC Tom Lendacky
2018-01-06 21:06 ` [tip:x86/pti] " tip-bot for Tom Lendacky
2018-01-08 10:08 ` Thomas Gleixner
2018-01-08 10:23 ` Woodhouse, David
2018-01-08 10:25 ` Thomas Gleixner
2018-01-08 10:40 ` Andrew Cooper
2018-01-08 11:10 ` Thomas Gleixner
2018-01-08 14:47 ` Tom Lendacky
2018-01-08 14:54 ` Andrew Cooper
2018-01-08 16:48 ` Dr. David Alan Gilbert
2018-01-08 17:01 ` Paolo Bonzini
2018-01-08 17:39 ` Tom Lendacky
2018-01-08 17:42 ` Paolo Bonzini
2018-01-17 17:21 ` Tom Lendacky
2018-01-17 17:53 ` Paolo Bonzini
2018-01-08 15:02 ` David Woodhouse
2018-01-08 15:15 ` Thomas Gleixner
2018-01-08 17:31 ` Tom Lendacky
2018-01-08 20:57 ` Thomas Gleixner
2018-01-05 16:08 ` Tom Lendacky [this message]
2018-01-06 21:06 ` [tip:x86/pti] x86/msr: Remove now unused definition of MFENCE_RDTSC feature tip-bot for Tom Lendacky
2018-01-05 16:56 ` [PATCH v1 0/3] x86/cpu/AMD: Make LFENCE a serializing instruction on AMD Borislav Petkov
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