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=-10.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,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 4459EC433E0 for ; Wed, 13 Jan 2021 17:24:34 +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 D01AB205CA for ; Wed, 13 Jan 2021 17:24:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D01AB205CA 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:References:Message-ID: Subject: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=yweqLlIu93+LvU9EwwGQDxa98VcESmIPaYzfRWGQju4=; b=ltHZrFs0B6nbHRhYKP1xnFBeK KMtO5MV2oLZmHXRrb/FduPZym+ngkXbCDqhh/og9dHzi5ajyfrlCSj6RinmlQVXPHCvjJQ1F8n7ab Ck8VVRjFlbwt3RazjOrW1cSBP11DArZDVxu8MENUTJPlC+CHv3b9gCzdz3sDVaEtx7SOfVOqwQlxY 4mGyGm58lD4INFsKgoCFUewCSNghuJkW0YLgQVu47jeTRhIrFCPL/m/nwm34iLU4MK/TZrdnmfneH vn3qpLaDtkGbqKc3rHUQXwfO5bc7ICgEoN1bXQiTcICTIdnd9O4i7kxiI0/obIBqAVP/9nx7ewSqi RbQwZlv1Q==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kzjqw-0001uq-Iz; Wed, 13 Jan 2021 17:22:38 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kzjqt-0001uP-5o for linux-arm-kernel@lists.infradead.org; Wed, 13 Jan 2021 17:22:36 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2CDA423437; Wed, 13 Jan 2021 17:22:31 +0000 (UTC) Date: Wed, 13 Jan 2021 17:22:28 +0000 From: Catalin Marinas To: Vincenzo Frascino Subject: Re: [PATCH v2 2/4] arm64: mte: Add asynchronous mode support Message-ID: <20210113172228.GE27045@gaia> References: <20210107172908.42686-1-vincenzo.frascino@arm.com> <20210107172908.42686-3-vincenzo.frascino@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210107172908.42686-3-vincenzo.frascino@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210113_122235_304135_B729323A X-CRM114-Status: GOOD ( 15.89 ) 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 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. > --- 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. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel