linux-kernel - [PATCH 02/10] x86/asm: Drop a comment left over from X86

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Date:	Tue, 26 Jan 2016 22:12:02 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 02/10] x86/asm: Drop a comment left over from X86_OOSTORE

From: "Michael S. Tsirkin" <mst@...hat.com>

The comment about wmb() being non-nop to deal with non-intel CPUs is a
left over from before commit

  09df7c4c8097 ("x86: Remove CONFIG_X86_OOSTORE").

It makes no sense now: in particular, wmb() is not a nop even for regular
intel CPUs because of weird use-cases e.g. dealing with WC memory.

Drop this comment.

Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
Cc: Andrey Konovalov <andreyknvl@...gle.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Davidlohr Bueso <dave@...olabs.net>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ralf Baechle <ralf@...ux-mips.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: virtualization <virtualization@...ts.linux-foundation.org>
Link: http://lkml.kernel.org/r/1452715911-12067-3-git-send-email-mst@redhat.com
Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/include/asm/barrier.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 5bce7865b623..d2aa66a3a4b5 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -11,10 +11,6 @@
  */
 
 #ifdef CONFIG_X86_32
-/*
- * Some non-Intel clones support out of order store. wmb() ceases to be a
- * nop for these.
- */
 #define mb() asm volatile(ALTERNATIVE("lock; addl $0,0(%%esp)", "mfence", \
 				      X86_FEATURE_XMM2) ::: "memory", "cc")
 #define rmb() asm volatile(ALTERNATIVE("lock; addl $0,0(%%esp)", "lfence", \
-- 
2.3.5