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From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>, "H Peter Anvin" <hpa@zytor.com>
Cc: "Ashok Raj" <ashok.raj@intel.com>,
	"Alan Cox" <alan@linux.intel.com>,
	"Ravi V Shankar" <ravi.v.shankar@intel.com>,
	"linux-kernel" <linux-kernel@vger.kernel.org>,
	"x86" <x86@kernel.org>, Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH 2/7] x86/cpufeatures: Enumerate MOVDIR64B instruction
Date: Mon, 23 Jul 2018 05:55:52 -0700	[thread overview]
Message-ID: <1532350557-98388-3-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1532350557-98388-1-git-send-email-fenghua.yu@intel.com>

MOVDIR64B moves 64-bytes as direct-store with 64-bytes write atomicity.
Direct store is implemented by using write combining (WC) for writing
data directly into memory without caching the data.

In low latency offload (e.g. Non-Volatile Memory, etc), MOVDIR64B writes
work descriptors (and data in some cases) to device-hosted work-queues
atomically without cache pollution.

Availability of the MOVDIR64B instruction is indicated by the
presence of the CPUID feature flag MOVDIR64B (CPUID.0x07.0x0:ECX[bit 28]).

Please check the latest Intel Architecture Instruction Set Extensions
and Future Features Programming Reference for more details on the CPUID
feature MOVDIR64B flag.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
 arch/x86/include/asm/cpufeatures.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 92630c469675..69f1137877b6 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -330,6 +330,7 @@
 #define X86_FEATURE_RDPID		(16*32+22) /* RDPID instruction */
 #define X86_FEATURE_CLDEMOTE		(16*32+25) /* CLDEMOTE instruction */
 #define X86_FEATURE_MOVDIRI		(16*32+27) /* MOVDIRI instruction */
+#define X86_FEATURE_MOVDIR64B		(16*32+28) /* MOVDIR64B instruction */
 
 /* AMD-defined CPU features, CPUID level 0x80000007 (EBX), word 17 */
 #define X86_FEATURE_OVERFLOW_RECOV	(17*32+ 0) /* MCA overflow recovery support */
-- 
2.5.0


  parent reply	other threads:[~2018-07-23 14:27 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-23 12:55 [PATCH 0/7] x86: Enable a few new instructions Fenghua Yu
2018-07-23 12:55 ` [PATCH 1/7] x86/cpufeatures: Enumerate MOVDIRI instruction Fenghua Yu
2018-07-23 12:55 ` Fenghua Yu [this message]
2018-07-23 12:55 ` [PATCH 3/7] x86/cpufeatures: Enumerate UMONITOR, UMWAIT, and TPAUSE instructions Fenghua Yu
2018-07-23 12:55 ` [PATCH 4/7] x86/umwait_contro: Set global umwait maximum time limit and umwait C0.2 state Fenghua Yu
2018-07-24  1:41   ` Andy Lutomirski
2018-08-01  9:01     ` Thomas Gleixner
2018-07-23 12:55 ` [PATCH 5/7] x86/vdso: Add vDSO functions for direct store instructions Fenghua Yu
2018-07-24  1:48   ` Andy Lutomirski
2018-07-24  3:42     ` Fenghua Yu
2018-07-24  5:27       ` Andy Lutomirski
2018-07-25 22:18         ` Fenghua Yu
2018-07-23 12:55 ` [PATCH 6/7] x86/vdso: Add vDSO functions for user wait instructions Fenghua Yu
2018-07-24  2:11   ` Andy Lutomirski
2018-07-24 15:14     ` Andy Lutomirski
2018-07-31 21:22     ` Thomas Gleixner
2018-07-31 21:38       ` Andy Lutomirski
2018-08-01  8:55         ` Thomas Gleixner
2018-07-23 12:55 ` [PATCH 7/7] selftests/vDSO: Add selftest to test vDSO functions for direct store and " Fenghua Yu

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