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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71A98C4332F for ; Wed, 30 Nov 2022 12:28:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234575AbiK3M21 (ORCPT ); Wed, 30 Nov 2022 07:28:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234232AbiK3M2Y (ORCPT ); Wed, 30 Nov 2022 07:28:24 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 75AE04C25F for ; Wed, 30 Nov 2022 04:28:23 -0800 (PST) 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> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.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.