From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61F15C433DF for ; Wed, 20 May 2020 08:29:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 27429206C3 for ; Wed, 20 May 2020 08:29:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="L+1U8zzm"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="H4yZxE/w" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 27429206C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=C0Oa+/QbY7GVa1eTA1V7eDOGtNYy9FT80bWNf4fmlHU=; b=L+1U8zzmj3bZnj 0LC9SbxGm1LnkTyzd17UtCoslR7Oz91ztPy98WCM6kPJtItZWB+IZNvPZ+k2hWOatei9/tTyc09P7 v4w6eppxfcF3kS1o+Dsucgg07hmxcEn9wIO0gcIonZFAEfTzKCkTQ3h2qlkfMBk1vN6UTC5ew+s7B 4rNF+a9JfvIoF/tJYrnkmtbT/F6DmrjLdZ5TYst6wIv0UejBEcOt8jgTnxlBERxVEkD0feqBH2Ftk mTCkIs0tl/ILbFdlnb3/nVZII4xeQPrTWCHmcBk02EeDIptSO/W7cehTfiQ2K8UAmiUbWKDWDACw/ TZ8khu0Ra5fZkF3GQ05Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbK64-00035N-Ui; Wed, 20 May 2020 08:29:04 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbK62-000352-D0 for linux-arm-kernel@lists.infradead.org; Wed, 20 May 2020 08:29:03 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 35915207ED; Wed, 20 May 2020 08:29:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589963341; bh=Q+iJzQpwjrFd6M+y+y1WH0wGJm9kOclpP9m1i3eCkoU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=H4yZxE/wBTDUafZJ+OAeSSn2ylH6Lg8vFhVIhMpZtgwPV7qteoI6eMBshap1zK6xn 58uihSJzToS1yATGGYPfY89uUdKLZge+pTAs6g6Q2q/a7ihx/jOlohJDIMZI/ZTwZC /a2hdNvz4WDPWFLROT5nbwc6chMjRBj+Jaupp4ew= Date: Wed, 20 May 2020 09:28:57 +0100 From: Will Deacon To: Linu Cherian Subject: Re: Clarification on necessary barriers before generating IPI Message-ID: <20200520082856.GA24293@willie-the-truck> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200520_012902_458869_C2C6BEFA X-CRM114-Status: UNSURE ( 8.73 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: maz@kernel.org, Linu Cherian , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, May 20, 2020 at 01:38:24PM +0530, Linu Cherian wrote: > How is it ensured that system register write using msr instruction(gic_send_sgi) > doesnt get reordered before the stores to IPI call processing > list(call_single_queue in kernel/smp.c), so that IPI is guaranteed to > be generated after the stores get completed. I think the flow is: DSB ST MSR SGI1R ISB and then on the receiver: MRS IAR DSB SY MSR EOIR ISB > CMIIW, Dont we need an isb() in addition to to the wmb() in the below code ? There is an isb?() in the code, after the loop. Are you saying it should be somewhere else? If so, why? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel