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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 740A2C433DB for ; Tue, 9 Feb 2021 19:58:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2368D64EAC for ; Tue, 9 Feb 2021 19:58:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233839AbhBIT4a (ORCPT ); Tue, 9 Feb 2021 14:56:30 -0500 Received: from foss.arm.com ([217.140.110.172]:55224 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233237AbhBISWQ (ORCPT ); Tue, 9 Feb 2021 13:22:16 -0500 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 8FE53113E; Tue, 9 Feb 2021 10:21:29 -0800 (PST) Received: from [10.37.8.18] (unknown [10.37.8.18]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 94D513F73B; Tue, 9 Feb 2021 10:21:27 -0800 (PST) Subject: Re: [PATCH v12 6/7] arm64: mte: Save/Restore TFSR_EL1 during suspend To: Catalin Marinas , Lorenzo Pieralisi Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Andrew Morton , Will Deacon , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Andrey Konovalov References: <20210208165617.9977-1-vincenzo.frascino@arm.com> <20210208165617.9977-7-vincenzo.frascino@arm.com> <20210209115533.GE1435@arm.com> <20210209143328.GA27791@e121166-lin.cambridge.arm.com> <20210209172821.GI1435@arm.com> From: Vincenzo Frascino Message-ID: <89c95a1e-cfd2-7840-3175-deaeb336190b@arm.com> Date: Tue, 9 Feb 2021 18:25:31 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210209172821.GI1435@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/9/21 5:28 PM, Catalin Marinas wrote: >> I don't think though you can "check" with IRQs disabled so I suspect >> that TFSR_EL1 has to be saved/restored (which means that there is a >> black out period where we run kernel code without being able to detect >> faults but there is no solution to that other than delaying saving the >> value to just before calling into PSCI). Likewise on resume from low >> power. > It depends on whether kasan_report can be called with IRQs disabled. I > don't see why not, so if this works I'd rather just call mte_check_async > (or whatever it's called) on the suspend path and zero the register on > resume (mte_suspend_exit). We avoid any saving of the state. Fine by me, I tried a quick test and can confirm that kasan_report can be invoked with IRQ disabled. -- Regards, Vincenzo