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=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 06CA7C433DB for ; Tue, 9 Feb 2021 14:51:28 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9CE3B64E5A for ; Tue, 9 Feb 2021 14:51:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9CE3B64E5A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TaNKDZ92YEDUfNWKDOOoNabhvF8QbaACtIVtoQM+/b8=; b=3MJwqdUuEfffXD0SvMV/64yiL gbvl97Llo2XPuJtAr7+hKArOcgXP+L31vpsYWnTLjtYRujE05IC8BQBwVJ6bLI70vVlQnIVDj1hyL zO+EmW9pL4ZX0peK6KcYHrhiO86ilRy7ablkYzz5AMUJNsb3GwRb29oEd5aq/uCj1y4bjaBQCOB3A 2sS5Xtw1f4zRnq3s47KOp8um9bxUC+lZ2Twyj9FHXbfa1PwWqcG8ctMjUIyJ1H+g4StKX7l+MgJCX /ppOsBfUHtLfg9MrnFQEslD7GvFzjrREDYsjoio8YEPi3Xsojg4wE547BE0KWR55Gu0aDqhVlWWnd qHIrbHLrg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9ULI-00020V-C8; Tue, 09 Feb 2021 14:50:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9ULE-0001yz-Rm for linux-arm-kernel@lists.infradead.org; Tue, 09 Feb 2021 14:50:14 +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 B9B54101E; Tue, 9 Feb 2021 06:50:11 -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 C0F223F73D; Tue, 9 Feb 2021 06:50:09 -0800 (PST) Subject: Re: [PATCH v12 6/7] arm64: mte: Save/Restore TFSR_EL1 during suspend To: Lorenzo Pieralisi , Catalin Marinas 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> From: Vincenzo Frascino Message-ID: <2a551330-111b-4cb4-51d1-190f2c6d8493@arm.com> Date: Tue, 9 Feb 2021 14:54:13 +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: <20210209143328.GA27791@e121166-lin.cambridge.arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210209_095013_152569_AE720AAC X-CRM114-Status: GOOD ( 19.76 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Branislav Rankov , Marco Elver , Andrey Konovalov , Evgenii Stepanov , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Alexander Potapenko , linux-arm-kernel@lists.infradead.org, Andrey Ryabinin , Andrew Morton , Will Deacon , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2/9/21 2:33 PM, Lorenzo Pieralisi wrote: >> Do we need a similar fix for TFSRE0_EL1? We get away with this if >> suspend is only entered on the idle (kernel) thread but I recall we >> could also enter suspend on behalf of a user process (I may be wrong >> though). > Yes, when we suspend the machine to RAM, we execute suspend on behalf > on a userspace process (but that's only running on 1 cpu, the others > are hotplugged out). > > IIUC (and that's an if) TFSRE0_EL1 is checked on kernel entry so I don't > think there is a need to save/restore it (just reset it on suspend > exit). > > TFSR_EL1, I don't see a point in saving/restoring it (it is a bit > per-CPU AFAICS) either, IMO we should "check" it on suspend (if it is > possible in that context) and reset it on resume. > > 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. > Ok, based on what you are saying it seems that the most viable solution here is to save and restore TFSR_EL1. I will update my code accordingly. > Thanks, > Lorenzo > -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel