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 AF9CCC433FE for ; Wed, 30 Nov 2022 12:29:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Lclx2H42vfE7Vnwg+PPKO/R66ZWjFTWHcolPFVgOEDo=; b=s5Z5y55T+b4W3m l3MxsFgUuWYVJsFonFbkl3tWNYU5NUkd5LkAxcnrpaP8L9pXc025hTTPnjTIykuGqGIVbKF5u6pow nsP2MyqL/IsO0lky5auRQLoo1hnWMgnttTPs0GH1YM75BQxYXxtLSN39Tlubgbc5hjMbbve/4Qic2 sWOWzUYILS240vUf2Uh3ZTVgYLAxJBPHUQVLdE7YRI74Q5t6dywTVeAWMS6/VVUUjXS/5qUe05+yP D0IufSNAHCEgEi5BsR6LL/+59mv0RJtuzqAwhMJ19VZTuliU9bp4Mqz3NYBl4naJwocyUSgetvLAE asrQ3s2XIQ8qwzMj0NbQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p0MCX-00G7I5-Hp; Wed, 30 Nov 2022 12:28:33 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p0MCT-00G7Fm-Iw for linux-arm-kernel@lists.infradead.org; Wed, 30 Nov 2022 12:28:31 +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 847D6D6E; Wed, 30 Nov 2022 04:28:29 -0800 (PST) Received: from [10.57.71.118] (unknown [10.57.71.118]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CBB8E3F73D; Wed, 30 Nov 2022 04:28:21 -0800 (PST) Message-ID: Date: Wed, 30 Nov 2022 12:28:17 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH] perf/arm-cmn: Add shutdown routine Content-Language: en-GB To: Will Deacon , Geoff Blake , linux-kernel@vger.kernel.org Cc: catalin.marinas@arm.com, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, Mark Rutland References: <20221125230153.49468-1-blakgeof@amazon.com> <166973320082.112522.10687339610259452670.b4-ty@kernel.org> From: Robin Murphy In-Reply-To: <166973320082.112522.10687339610259452670.b4-ty@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221130_042829_716171_9C3748B5 X-CRM114-Status: GOOD ( 12.82 ) 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: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2022-11-29 19:52, Will Deacon wrote: > On Fri, 25 Nov 2022 17:01:53 -0600, Geoff Blake wrote: >> The CMN driver does not gracefully handle all >> restart cases, such as kexec. On a kexec if the >> arm-cmn driver is in use it can be left in a state >> with still active events that can cause spurious and/or >> unhandled interrupts that appear as non-fatal kernel errors >> like below, that can be confusing and misleading: >> >> [...] > > Applied to will (for-next/perf), thanks! > > [1/1] perf/arm-cmn: Add shutdown routine > https://git.kernel.org/will/c/316f862a787c Oh, if I'd seen this I'd have said the same thing as when asked about it off-list, that it's needlessly overcomplicated and doesn't really solve the problem anyway. If there's a need to be robust against spurious interrupts then that needs to be done in the interrupt handler. Even if we do think it's worth stopping the PMU on shutdown, as we do on remove, that still only needs a single register write (per the current remove implementation). Thanks, Robin. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel