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=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 6CF04C07E98 for ; Mon, 5 Jul 2021 09:16:42 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 3D183613DD for ; Mon, 5 Jul 2021 09:16:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3D183613DD 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=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Os3u9OnYzSTu1G3JnHUzbDYxmZstzOnZto7ltTRK4J0=; b=rP9aBqGhRhJN1/ 7sb0zETtUujgRE5+2apnHMFggL5it7jM7Fo9rPi+X2XaJxGnY2dz1uGuKrbr3ltXKuv26MTHqmKg4 qQ6m3Vo1TvT9rZYZGfHsKiq+k7+TLMcauGR1anXdxUhx3o96gBbOoTolhGXE0lnx/krd0xednX97B 9KnhKeOSrPjr8etOMbDFEvBtKFFdev7HZjhSFTQP0hOucD7vOYzQ+LXUJrjXL/TkSkNRjf1/KtzMb yiNFWxCUFhHv9EHDuN+7Gt668ULlsg8dfM9Fsk/VWL2kA4xlJK2i5ImSqAhONppNcrEFSMMq+bv3y 3VlcXJ63edImL/xZ1Z1g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m0Kgm-008Nub-F6; Mon, 05 Jul 2021 09:14:52 +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 1m0Kgj-008NtT-8l for linux-arm-kernel@lists.infradead.org; Mon, 05 Jul 2021 09:14:50 +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 19AA313D5; Mon, 5 Jul 2021 02:14:42 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.8.167]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 313C43F5A1; Mon, 5 Jul 2021 02:14:38 -0700 (PDT) Date: Mon, 5 Jul 2021 10:14:36 +0100 From: Mark Rutland To: Bharat Bhushan Cc: catalin.marinas@arm.com, will@kernel.org, daniel.lezcano@linaro.org, maz@kernel.org, konrad.dybcio@somainline.org, saiprakash.ranjan@codeaurora.org, robh@kernel.org, marcan@marcan.st, suzuki.poulose@arm.com, broonie@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Linu Cherian Subject: Re: [PATCH] clocksource: Add Marvell Errata-38627 workaround Message-ID: <20210705091436.GE38629@C02TD0UTHF1T.local> References: <20210705060843.3150-1-bbhushan2@marvell.com> <20210705090753.GD38629@C02TD0UTHF1T.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210705090753.GD38629@C02TD0UTHF1T.local> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210705_021449_397868_AA519959 X-CRM114-Status: GOOD ( 15.43 ) 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-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 Mon, Jul 05, 2021 at 10:07:53AM +0100, Mark Rutland wrote: > Hi Bharat, > > On Mon, Jul 05, 2021 at 11:38:43AM +0530, Bharat Bhushan wrote: > > CPU pipeline have unpredicted behavior when timer > > interrupt appears and then disappears prior to the > > exception happening. Time interrupt appears on timer > > expiry and disappears when timer programming or timer > > disable. This typically can happen when a load > > instruction misses in the cache, which can take > > few hundreds of cycles, and an interrupt appears > > after the load instruction starts executing but > > disappears before the load instruction completes. > > Could you elaborate on the scenario? What sort of unpredictable > behaviour can occur? e.g: > > * Does the CPU lockup? > * Does the CPU take the exception at all? > * Does the load behave erroneously? > * Does any CPU state (e.g. GPRs, PC, PSTATE) become corrupted? > > Does the problem manifest when IRQs are masked by DAIF.I, or by > CNT8_CTL_EL0.{IMASK,ENABLE} ? Whoops, that was supposed to say: | CNT*_CTL_EL0.{IMASK,ENABLE} ... i.e. those fields in either CNTP_CTL_EL0 or CNTV_CTL_EL0. Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel