From patchwork Thu Aug 16 15:35:56 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Stabellini X-Patchwork-Id: 1333731 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id DE17C40210 for ; Thu, 16 Aug 2012 15:40:22 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1T227z-00089Y-Je; Thu, 16 Aug 2012 15:36:55 +0000 Received: from smtp02.citrix.com ([66.165.176.63]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1T227j-00086M-JH for linux-arm-kernel@lists.infradead.org; Thu, 16 Aug 2012 15:36:40 +0000 X-IronPort-AV: E=Sophos;i="4.77,778,1336363200"; d="scan'208";a="205386125" Received: from ftlpmailmx01.citrite.net ([10.13.107.65]) by FTLPIPO02.CITRIX.COM with ESMTP/TLS/RC4-MD5; 16 Aug 2012 11:36:36 -0400 Received: from ukmail1.uk.xensource.com (10.80.16.128) by smtprelay.citrix.com (10.13.107.65) with Microsoft SMTP Server id 8.3.213.0; Thu, 16 Aug 2012 11:36:36 -0400 Received: from kaball.uk.xensource.com ([10.80.2.59]) by ukmail1.uk.xensource.com with esmtp (Exim 4.69) (envelope-from ) id 1T227b-0007Iu-2d; Thu, 16 Aug 2012 16:36:31 +0100 From: Stefano Stabellini To: Subject: [PATCH v3 04/25] xen/arm: sync_bitops Date: Thu, 16 Aug 2012 16:35:56 +0100 Message-ID: <1345131377-14713-4-git-send-email-stefano.stabellini@eu.citrix.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: MIME-Version: 1.0 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [66.165.176.63 listed in list.dnswl.org] -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record 0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: xen-devel@lists.xensource.com, linaro-dev@lists.linaro.org, Ian.Campbell@citrix.com, arnd@arndb.de, konrad.wilk@oracle.com, catalin.marinas@arm.com, Stefano Stabellini , tim@xen.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org sync_bitops functions are equivalent to the SMP implementation of the original functions, independently from CONFIG_SMP being defined. We need them because _set_bit etc are not SMP safe if !CONFIG_SMP. But under Xen you might be communicating with a completely external entity who might be on another CPU (e.g. two uniprocessor guests communicating via event channels and grant tables). So we need a variant of the bit ops which are SMP safe even on a UP kernel. Signed-off-by: Stefano Stabellini Acked-by: Konrad Rzeszutek Wilk --- arch/arm/include/asm/sync_bitops.h | 27 +++++++++++++++++++++++++++ 1 files changed, 27 insertions(+), 0 deletions(-) create mode 100644 arch/arm/include/asm/sync_bitops.h diff --git a/arch/arm/include/asm/sync_bitops.h b/arch/arm/include/asm/sync_bitops.h new file mode 100644 index 0000000..63479ee --- /dev/null +++ b/arch/arm/include/asm/sync_bitops.h @@ -0,0 +1,27 @@ +#ifndef __ASM_SYNC_BITOPS_H__ +#define __ASM_SYNC_BITOPS_H__ + +#include +#include + +/* sync_bitops functions are equivalent to the SMP implementation of the + * original functions, independently from CONFIG_SMP being defined. + * + * We need them because _set_bit etc are not SMP safe if !CONFIG_SMP. But + * under Xen you might be communicating with a completely external entity + * who might be on another CPU (e.g. two uniprocessor guests communicating + * via event channels and grant tables). So we need a variant of the bit + * ops which are SMP safe even on a UP kernel. + */ + +#define sync_set_bit(nr, p) _set_bit(nr, p) +#define sync_clear_bit(nr, p) _clear_bit(nr, p) +#define sync_change_bit(nr, p) _change_bit(nr, p) +#define sync_test_and_set_bit(nr, p) _test_and_set_bit(nr, p) +#define sync_test_and_clear_bit(nr, p) _test_and_clear_bit(nr, p) +#define sync_test_and_change_bit(nr, p) _test_and_change_bit(nr, p) +#define sync_test_bit(nr, addr) test_bit(nr, addr) +#define sync_cmpxchg cmpxchg + + +#endif