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=-10.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 A0A55C433E0 for ; Thu, 14 Jan 2021 09:42:19 +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 4DBF823A21 for ; Thu, 14 Jan 2021 09:42:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4DBF823A21 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=Tln069qP4fTsMnwJzWk6etNBPjdU0QfRnPe5/9rYUoA=; b=hMG90BeSOz94GMJgaImkfSUps SN+ZUZtFyLpmp9gQiXQftIRRNjC7YYQ2ei4gcfGMMXfnXiA6M/x35qdpdC2rkMmDM2JaQErAIET0K ByF6vDJ6T14H2lYVCRUU0pmOWN8/6Ly4wEc1ggDpcni3nT/uGZjo5+GK1R/8iYTBriwZdzWagacAL VHhpjbrLdN4aXaaQPrsWh426oGqfgq6CZ4og4kfROfOCpPAhezc+zM8I2PjSxOoIeCIELoN9mQUfM NVrgpKxvBJqow9o7epfmykKEGCW6h3aJ22EiKCeoqzxtt+Rbz2TI8bCJtWEBlgIY1iahqj+3wqkbW +IpOMoZ+g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kzz75-0001oS-IN; Thu, 14 Jan 2021 09:40:19 +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 1kzz6O-0001Zd-Ld for linux-arm-kernel@lists.infradead.org; Thu, 14 Jan 2021 09:39:39 +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 AE12A1FB; Thu, 14 Jan 2021 01:39:35 -0800 (PST) Received: from [10.0.0.31] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1EC303F70D; Thu, 14 Jan 2021 01:39:32 -0800 (PST) Subject: Re: [PATCH v2 2/4] arm64: mte: Add asynchronous mode support To: Catalin Marinas References: <20210107172908.42686-1-vincenzo.frascino@arm.com> <20210107172908.42686-3-vincenzo.frascino@arm.com> <20210113172228.GE27045@gaia> From: Vincenzo Frascino Message-ID: <16a57293-37fa-4526-e6cd-61f80b93e12a@arm.com> Date: Thu, 14 Jan 2021 09:43:19 +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: <20210113172228.GE27045@gaia> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210114_043936_954159_314C928F X-CRM114-Status: GOOD ( 19.18 ) 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 , 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 1/13/21 5:22 PM, Catalin Marinas wrote: > On Thu, Jan 07, 2021 at 05:29:06PM +0000, Vincenzo Frascino wrote: >> MTE provides an asynchronous mode for detecting tag exceptions. In >> particular instead of triggering a fault the arm64 core updates a >> register which is checked by the kernel at the first entry after the tag >> exception has occurred. > > Just rephrase the "tag exception" here as there's no exception taken. > Also we don't check this only when the kernel is first entered after a > tag check fault, as per patch 3. > Ok, I will clarify it in v3. >> --- a/arch/arm64/kernel/mte.c >> +++ b/arch/arm64/kernel/mte.c >> @@ -153,8 +153,35 @@ void mte_init_tags(u64 max_tag) >> >> void mte_enable_kernel(enum kasan_arg_mode mode) >> { >> - /* Enable MTE Sync Mode for EL1. */ >> - sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); >> + const char *m; >> + >> + /* Preset parameter values based on the mode. */ >> + switch (mode) { >> + case KASAN_ARG_MODE_OFF: >> + return; >> + case KASAN_ARG_MODE_LIGHT: >> + /* Enable MTE Async Mode for EL1. */ >> + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_ASYNC); >> + m = "asynchronous"; >> + break; >> + case KASAN_ARG_MODE_DEFAULT: >> + case KASAN_ARG_MODE_PROD: >> + case KASAN_ARG_MODE_FULL: >> + /* Enable MTE Sync Mode for EL1. */ >> + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); >> + m = "synchronous"; >> + break; >> + default: >> + /* >> + * kasan mode should be always set hence we should >> + * not reach this condition. >> + */ >> + WARN_ON_ONCE(1); >> + return; >> + } > > I guess the switch statement here will be re-written as we want kasan to > drive the actual sync/async modes as it sees fit rather than MTE > guessing what PROD/FULL/LIGHT means. > Yes, this is correct, it will present only sync/async mode. -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel