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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id D9474C43327 for ; Fri, 26 Jun 2026 17:35:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=tG9B+nb6q7AJXdqBeEZmjPB+auopz/lufEKOo/Tem/E=; b=er64HMVwWQBlrV/CfQUbf/GISQ STmtl6Fm4qNlI4kqgM1JeixMLgY/1F2N3wJXhVbpK6ARAxKBj/bxFIUTjAN58Wo+SR2a+MwILroo9 re2bNui1Ak3zNqvWVCrZMQTu4pIjrVVGrUaTwX3X8Fg0DLFvnB1I0CNbpOhEmhWFyzDEJQbpkZvxE Oh5b/CpgX69RnQ87sMd5tfujHyXJcayIpg8Jz+FJmvwJkqJQ00+mSJpRRGTCFUl2ql2mMPTuqCr9c Sz0H+l9cAVriaU55zAfJVOhT+7n/xTMWCRtacFhOVKPIR3COKm4aG9/sR4H3UUNtmFoK73JEam+YN BLYd4j7A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wdA5b-0000000BgYY-2f9d; Fri, 26 Jun 2026 17:11:39 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wdA5Y-0000000BgXy-1MKC; Fri, 26 Jun 2026 17:11:37 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2EEAA1F60; Fri, 26 Jun 2026 10:11:30 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BFA563F632; Fri, 26 Jun 2026 10:11:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782493894; bh=2Utd0N86MYNjJo+OrS+WeKcY0n7FZPkf9EAQgABOrpw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mWabBNRIZ+FuDwevXn80U/01DGm1UIj9+lSegSodD3K4KHVC5SqDQuvu1fCVjKaNq tYVHSozu47HG5f0KDSGbuppXwpLz97F0fMxy9j6Tc/eZzmaw0vCN3TUPdT3W0MowWD wxjnNqas9sm94L4ui9R6FbMysK3ZODCWqtouZ+Ho= Date: Fri, 26 Jun 2026 18:11:29 +0100 From: Catalin Marinas To: Kiryl Shutsemau Cc: Will Deacon , James Morse , Mark Rutland , Marc Zyngier , Doug Anderson , Petr Mladek , Thomas Gleixner , Andrew Morton , Baoquan He , Puranjay Mohan , Usama Arif , Breno Leitao , Julien Thierry , Lecopzer Chen , Sumit Garg , kernel-team@meta.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "Kiryl Shutsemau (Meta)" Subject: Re: [PATCH v4 3/4] drivers/firmware: add SDEI cross-CPU NMI service for arm64 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260626_101136_423223_7B5A8AEC X-CRM114-Status: GOOD ( 10.66 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jun 17, 2026 at 08:20:04PM +0100, Kiryl Shutsemau wrote: > +/* > + * Raise callback for nmi_trigger_cpumask_backtrace(): signal event 0 > + * at every CPU still pending in @mask. The framework excludes the local > + * CPU from @mask before calling us. > + */ > +static void sdei_nmi_raise_backtrace(cpumask_t *mask) > +{ > + unsigned int cpu; > + > + for_each_cpu(cpu, mask) > + sdei_nmi_fire(cpu); > +} Does this need a barrier as in patch 4? Sashiko spotted that backtrace_mask won't be visible without a dsb(ishst). Again, as per my comment in patch 4, we get away with this because of the TF-A implementation but that's not guaranteed (we could ask for the SDEI spec to be updated assuming all firmware implementations do this). -- Catalin