From patchwork Wed Sep 16 15:49:30 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boqun Feng X-Patchwork-Id: 518471 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 64381140180 for ; Thu, 17 Sep 2015 01:55:00 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b=zFtlrf6K; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3E3741A2CF5 for ; Thu, 17 Sep 2015 01:55:00 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b=zFtlrf6K; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mail-ob0-x22f.google.com (mail-ob0-x22f.google.com [IPv6:2607:f8b0:4003:c01::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 5639C1A089E for ; Thu, 17 Sep 2015 01:50:12 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b=zFtlrf6K; dkim-atps=neutral Received: by obqa2 with SMTP id a2so152859108obq.3 for ; Wed, 16 Sep 2015 08:50:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=l90R4FxPkQMKrFDYjoVn7V9yWnhHwq0xFfYdAP72u4c=; b=zFtlrf6Ku33suomw7Fzr8AcbyEPn9DuLFlIu5YSePvdBVlzRxczGgm/Xd8ccqfPK+A RcFUqvX1D/NyBte6d+jD++6gMCSkfhhETvztT9HVcJv8NarmKxGtwteio+egx3MGnYlW xLaXlzpJ4u+XnD3iVL5/QuHw0FLnLDoC7Vn0XYJJSkrsaChqv8n8YmKuVKfdG33AM+wL 4Jn1xv5laWMNvK89G8ztriefyLo7HObn+UARsKBCQ1HPM9FEZTOjfdxVb66+UNq4B+Z6 EKfDaBueecNOqT3P8iuKVEgabs3pwP8NaNd0qd9IIxdWGdfjm0Y7AGg3Xe8dQC4QVZar JcJw== X-Received: by 10.60.85.73 with SMTP id f9mr24138578oez.66.1442418610157; Wed, 16 Sep 2015 08:50:10 -0700 (PDT) Received: from localhost (vm.fixme.name. [192.157.208.129]) by smtp.gmail.com with ESMTPSA id pp2sm1960811oeb.1.2015.09.16.08.50.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Sep 2015 08:50:09 -0700 (PDT) From: Boqun Feng To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [RFC v2 2/7] atomics: Allow architectures to define their own __atomic_op_* helpers Date: Wed, 16 Sep 2015 23:49:30 +0800 Message-Id: <1442418575-12297-3-git-send-email-boqun.feng@gmail.com> X-Mailer: git-send-email 2.5.1 In-Reply-To: <1442418575-12297-1-git-send-email-boqun.feng@gmail.com> References: <1442418575-12297-1-git-send-email-boqun.feng@gmail.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Waiman Long , Peter Zijlstra , Boqun Feng , Will Deacon , Paul Mackerras , Thomas Gleixner , "Paul E. McKenney" , Ingo Molnar MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Some architectures may have their special barriers for acquire, release and fence semantics, so that general memory barriers(smp_mb__*_atomic()) in the default __atomic_op_*() may be too strong, so allow architectures to define their own helpers which can overwrite the default helpers. Signed-off-by: Boqun Feng --- include/linux/atomic.h | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 00a5763..590c023 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -34,20 +34,29 @@ * The idea here is to build acquire/release variants by adding explicit * barriers on top of the relaxed variant. In the case where the relaxed * variant is already fully ordered, no additional barriers are needed. + * + * Besides, if an arch has a special barrier for acquire/release, it could + * implement its own __atomic_op_* and use the same framework for building + * variants */ +#ifndef __atomic_op_acquire #define __atomic_op_acquire(op, args...) \ ({ \ typeof(op##_relaxed(args)) __ret = op##_relaxed(args); \ smp_mb__after_atomic(); \ __ret; \ }) +#endif +#ifndef __atomic_op_release #define __atomic_op_release(op, args...) \ ({ \ smp_mb__before_atomic(); \ op##_relaxed(args); \ }) +#endif +#ifndef __atomic_op_fence #define __atomic_op_fence(op, args...) \ ({ \ typeof(op##_relaxed(args)) __ret; \ @@ -56,6 +65,7 @@ smp_mb__after_atomic(); \ __ret; \ }) +#endif /* atomic_add_return_relaxed */ #ifndef atomic_add_return_relaxed