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 EF2E9C433FE for ; Wed, 30 Nov 2022 13:30:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235005AbiK3NaB (ORCPT ); Wed, 30 Nov 2022 08:30:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235612AbiK3N34 (ORCPT ); Wed, 30 Nov 2022 08:29:56 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83E656DCEA for ; Wed, 30 Nov 2022 05:29:53 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2EF25B81B4E for ; Wed, 30 Nov 2022 13:29:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D017C433D6; Wed, 30 Nov 2022 13:29:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669814990; bh=sP2qxHqOzBLVqNoiwojKC0COyARR01VWRMLMQXAbFHs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KFNR8KlKCWZYPbBmoi9ggWRPIauHdC6kTOYCHlWXKGCFcubWTJFeOrCz7f0sNUWcU uA9nt20wyz4yEw+nVtrg8vxiBk8ZXzqtXPzH6LGdyWfeQH1IfkYMiU8937x5ct7vNk nHuyk49wEt6MKfD2pYrRdu6w9JtV2Puj/TIQ+a+dV55w5rLS96wqecsRRM9IWUBgoF 5TvXXtLN7wf7NkMyTH2X6KAdJG3137NhhZx4mB2iqI9QycG+RNiaL2ySfHndq2M2Gs IIIutVLowic/XjbYGz97h2s+fl+piub14eI/FwicshDxWf0loN7QUk9xDgYR6hKXxB lsxNfS8FNI4qQ== Date: Wed, 30 Nov 2022 13:29:45 +0000 From: Will Deacon To: Robin Murphy Cc: Geoff Blake , linux-kernel@vger.kernel.org, catalin.marinas@arm.com, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, Mark Rutland Subject: Re: [PATCH] perf/arm-cmn: Add shutdown routine Message-ID: <20221130132945.GA27624@willie-the-truck> References: <20221125230153.49468-1-blakgeof@amazon.com> <166973320082.112522.10687339610259452670.b4-ty@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 30, 2022 at 12:28:17PM +0000, Robin Murphy wrote: > 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). Sorry Robin, I didn't spot that you weren't on cc for this. I've dropped the patch locally and I'll update the branches later on today. Please can you help Geoff come up with something better? Will