From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759464AbYHOQ5S (ORCPT ); Fri, 15 Aug 2008 12:57:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754553AbYHOQ5F (ORCPT ); Fri, 15 Aug 2008 12:57:05 -0400 Received: from tomts25-srv.bellnexxia.net ([209.226.175.188]:44119 "EHLO tomts25-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754436AbYHOQ5D (ORCPT ); Fri, 15 Aug 2008 12:57:03 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AuYEAFxQpUhMRKxB/2dsb2JhbACBYrIZgVc Date: Fri, 15 Aug 2008 12:56:59 -0400 From: Mathieu Desnoyers To: Linus Torvalds Cc: Ingo Molnar , Jeremy Fitzhardinge , Harvey Harrison , Andi Kleen , Steven Rostedt , Steven Rostedt , LKML , Thomas Gleixner , Peter Zijlstra , Andrew Morton , David Miller , Roland McGrath , Ulrich Drepper , Rusty Russell , Gregory Haskins , Arnaldo Carvalho de Melo , "Luis Claudio R. Goncalves" , Clark Williams , Christoph Lameter , "H. Peter Anvin" Subject: [PATCH] x86 : spinlock use LOCK_PREFIX Message-ID: <20080815165659.GD21138@Krystal> References: <20080814205815.GA14076@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 12:45:13 up 71 days, 21:25, 7 users, load average: 1.48, 1.37, 1.01 User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org x86 : spinlock use LOCK_PREFIX * Linus Torvalds (torvalds@linux-foundation.org) wrote: > > > On Thu, 14 Aug 2008, Mathieu Desnoyers wrote: > > > > Changing the 0x90 (single-byte nop) currently used into a 0x3E DS segment > > override prefix should fix this issue. Since the default of the atomic > > instructions is to use the DS segment anyway, it should not affect the > > behavior. > > Ok, so I think this is an _excellent_ patch, but I'd like to also then use > LOCK_PREFIX in include/asm-x86/futex.h. > > See commit 9d55b9923a1b7ea8193b8875c57ec940dc2ff027. > > Linus Unless there a rationale for this, I think these be changed to LOCK_PREFIX too. grep "lock ;" include/asm-x86/spinlock.h "lock ; cmpxchgw %w1,%2\n\t" asm volatile("lock ; xaddl %0, %1\n" "lock ; cmpxchgl %1,%2\n\t" Applies to 2.6.27-rc2. Signed-off-by: Mathieu Desnoyers CC: Linus Torvalds CC: H. Peter Anvin CC: Jeremy Fitzhardinge CC: Roland McGrath CC: Ingo Molnar Cc: Steven Rostedt CC: Steven Rostedt CC: Thomas Gleixner CC: Peter Zijlstra CC: Andrew Morton CC: David Miller CC: Ulrich Drepper CC: Rusty Russell CC: Gregory Haskins CC: Arnaldo Carvalho de Melo CC: "Luis Claudio R. Goncalves" CC: Clark Williams CC: Christoph Lameter CC: Andi Kleen CC: Harvey Harrison --- include/asm-x86/spinlock.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) Index: linux-2.6-lttng/include/asm-x86/spinlock.h =================================================================== --- linux-2.6-lttng.orig/include/asm-x86/spinlock.h 2008-08-15 12:51:59.000000000 -0400 +++ linux-2.6-lttng/include/asm-x86/spinlock.h 2008-08-15 12:52:10.000000000 -0400 @@ -97,7 +97,7 @@ static __always_inline int __ticket_spin "jne 1f\n\t" "movw %w0,%w1\n\t" "incb %h1\n\t" - "lock ; cmpxchgw %w1,%2\n\t" + LOCK_PREFIX "cmpxchgw %w1,%2\n\t" "1:" "sete %b1\n\t" "movzbl %b1,%0\n\t" @@ -135,7 +135,7 @@ static __always_inline void __ticket_spi int inc = 0x00010000; int tmp; - asm volatile("lock ; xaddl %0, %1\n" + asm volatile(LOCK_PREFIX "xaddl %0, %1\n" "movzwl %w0, %2\n\t" "shrl $16, %0\n\t" "1:\t" @@ -162,7 +162,7 @@ static __always_inline int __ticket_spin "cmpl %0,%1\n\t" "jne 1f\n\t" "addl $0x00010000, %1\n\t" - "lock ; cmpxchgl %1,%2\n\t" + LOCK_PREFIX "cmpxchgl %1,%2\n\t" "1:" "sete %b1\n\t" "movzbl %b1,%0\n\t" -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68