From patchwork Fri Jun 25 14:56:49 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 56948 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 1E399B6F10 for ; Sat, 26 Jun 2010 04:30:28 +1000 (EST) Received: from localhost ([127.0.0.1]:49143 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OSDex-0001oY-6x for incoming@patchwork.ozlabs.org; Fri, 25 Jun 2010 14:29:51 -0400 Received: from [140.186.70.92] (port=46279 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OSCxn-0003wG-HQ for qemu-devel@nongnu.org; Fri, 25 Jun 2010 13:45:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OSAL0-0005vA-1n for qemu-devel@nongnu.org; Fri, 25 Jun 2010 10:57:05 -0400 Received: from goliath.siemens.de ([192.35.17.28]:17786) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OSAKz-0005ty-LZ for qemu-devel@nongnu.org; Fri, 25 Jun 2010 10:57:01 -0400 Received: from mail2.siemens.de (mail2.siemens.de [139.25.208.11]) by goliath.siemens.de (8.12.11.20060308/8.12.11) with ESMTP id o5PEuvqG016771 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 25 Jun 2010 16:56:57 +0200 Received: from mchn012c.mchp.siemens.de (mchn012c.mchp.siemens.de [139.25.109.167] (may be forged)) by mail2.siemens.de (8.12.11.20060308/8.12.11) with ESMTP id o5PEuvZa013168; Fri, 25 Jun 2010 16:56:57 +0200 From: Jan Kiszka To: qemu-devel@nongnu.org, Anthony Liguori Date: Fri, 25 Jun 2010 16:56:49 +0200 Message-Id: <9a37eceacb7bb54e123bab9a31094d464d3c9040.1277477810.git.jan.kiszka@siemens.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: References: In-Reply-To: References: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4-2.6 Cc: Glauber Costa , Marcelo Tosatti , Avi Kivity , Alexander Graf Subject: [Qemu-devel] [PATCH 1/8] Introduce proper compiler barrier X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Define barrier() as optimization barrier and replace (potentially unreliable) asm("") fences. Signed-off-by: Jan Kiszka --- cpu-exec.c | 5 +++-- qemu-barrier.h | 3 +++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/cpu-exec.c b/cpu-exec.c index 026980a..525b3b4 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -21,6 +21,7 @@ #include "disas.h" #include "tcg.h" #include "kvm.h" +#include "qemu-barrier.h" #if !defined(CONFIG_SOFTMMU) #undef EAX @@ -233,7 +234,7 @@ int cpu_exec(CPUState *env1) use it. */ QEMU_BUILD_BUG_ON (sizeof (saved_env_reg) != sizeof (env)); saved_env_reg = (host_reg_t) env; - asm(""); + barrier(); env = env1; if (exit_request) { @@ -669,7 +670,7 @@ int cpu_exec(CPUState *env1) #endif /* restore global registers */ - asm(""); + barrier(); env = (void *) saved_env_reg; /* fail safe : never use cpu_single_env outside cpu_exec() */ diff --git a/qemu-barrier.h b/qemu-barrier.h index 3bd1075..b77fce2 100644 --- a/qemu-barrier.h +++ b/qemu-barrier.h @@ -4,4 +4,7 @@ /* FIXME: arch dependant, x86 version */ #define smp_wmb() asm volatile("" ::: "memory") +/* Compiler barrier */ +#define barrier() asm volatile("" ::: "memory") + #endif