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=-9.0 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 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 50D01C433E6 for ; Fri, 15 Jan 2021 15:10:04 +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 0CD9A2054F for ; Fri, 15 Jan 2021 15:10:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CD9A2054F 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=oG1M3qH25NpJJnccgpK2EXH5wZGUykEByhhmdZ5RMl4=; b=Xc7YKF4YGd1r88CR0lyo2mAJW Eu3hsAOc+POync90yu6aa7aiIMGB6HINCvaZnZaUjAmw4LLzD2KyZytXfEavcJob1e50EJpF9B2tR NJp8h7UcZ5DC0fVN7pHin3w/TgtbdXPv8WTncRxWu2QLUY99+5a1czMRHw7VhzvjSQbF08FcRec7f 11912xK2J9O9mU6f5IONLumY1y+gOlxLXMwITeO7Jf5QN17h3mNy5sfPCSiSpksiG/XlERUQaBl3y cqK5tITSsrb256VzeqqAfwrXLV3Wlxfx96K/Buq7wi7AWZmzCkJBqvBNNfJfWsdYOE8uFvjyIvd2i 24DXQuXxw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l0QiG-0001jJ-M8; Fri, 15 Jan 2021 15:08:32 +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 1l0Qi9-0001iR-QM for linux-arm-kernel@lists.infradead.org; Fri, 15 Jan 2021 15:08:30 +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 1D92BD6E; Fri, 15 Jan 2021 07:08:23 -0800 (PST) Received: from C02TD0UTHF1T.local (unknown [10.57.41.13]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 270B53F70D; Fri, 15 Jan 2021 07:08:18 -0800 (PST) Date: Fri, 15 Jan 2021 15:08:11 +0000 From: Mark Rutland To: Vincenzo Frascino Subject: Re: [PATCH v3 1/4] kasan, arm64: Add KASAN light mode Message-ID: <20210115150811.GA44111@C02TD0UTHF1T.local> References: <20210115120043.50023-1-vincenzo.frascino@arm.com> <20210115120043.50023-2-vincenzo.frascino@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210115120043.50023-2-vincenzo.frascino@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210115_100825_914496_56212387 X-CRM114-Status: GOOD ( 17.79 ) 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: Marco Elver , Catalin Marinas , Branislav Rankov , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, Alexander Potapenko , Evgenii Stepanov , Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , Will Deacon , linux-arm-kernel@lists.infradead.org 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 Fri, Jan 15, 2021 at 12:00:40PM +0000, Vincenzo Frascino wrote: > Architectures supported by KASAN HW can provide a light mode of > execution. On an MTE enabled arm64 hw for example this can be identified > with the asynch mode of execution. > In this mode, if a tag check fault occurs, the TFSR_EL1 register is > updated asynchronously. The kernel checks the corresponding bits > periodically. What's the expected usage of this relative to prod, given that this has to be chosen at boot time? When/where is this expected to be used relative to prod mode? > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 18fce223b67b..3a7c5beb7096 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -231,7 +231,7 @@ static inline const void *__tag_set(const void *addr, u8 tag) > } > > #ifdef CONFIG_KASAN_HW_TAGS > -#define arch_enable_tagging() mte_enable_kernel() > +#define arch_enable_tagging(mode) mte_enable_kernel(mode) Rather than passing a mode in, I think it'd be better to have: * arch_enable_tagging_prod() * arch_enable_tagging_light() ... that we can map in the arch code to separate: * mte_enable_kernel_sync() * mte_enable_kernel_async() ... as by construction that avoids calls with an unhandled mode, and we wouldn't need the mode enum kasan_hw_tags_mode... > +static inline int hw_init_mode(enum kasan_arg_mode mode) > +{ > + switch (mode) { > + case KASAN_ARG_MODE_LIGHT: > + return KASAN_HW_TAGS_ASYNC; > + default: > + return KASAN_HW_TAGS_SYNC; > + } > +} ... and we can just have a wrapper like this to call either of the two functions directly, i.e. static inline void hw_enable_tagging_mode(enum kasan_arg_mode mode) { if (mode == KASAN_ARG_MODE_LIGHT) arch_enable_tagging_mode_light(); else arch_enable_tagging_mode_prod(); } Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel