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 1DE99C433E0 for ; Thu, 14 Jan 2021 09:39:05 +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 7E3C123A21 for ; Thu, 14 Jan 2021 09:39:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E3C123A21 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=DQ9v6+blXmjQeHs1g2YC+0lw8fOXroFc5pR82zDbT/c=; b=vjjoUjgSx8sbNpEIzTLN8SKU5 JWxnIdgHFdY4OkQXg8fSEROSwqOQ5H7nh4d6WXs3sUcO8Hb+LDG6PuAB7l66OHpSgUgmMoqkWxAX4 zddAPN15Bu/Qw0TuxD4n/6oY3Hm61vrpXjKx7hcJ6UzRBEsqGirbhDr1h6IVTOaPHYrQaisoim+eD oofWPKdalv1PJbGmFeQ1KVCKByWQXm+ACTxALzw8+/DByZ8N5n98zfQGV3HgTdGxNThsh9neCdL/U LbTTS3zX6PB9uGW16I6+qJTs3FiDKK6pUADls2eb009QTzPIZHhdbTqHHhIedZf49f/b3YAxGW9yL UQlgUWPxw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kzz4T-0000U6-2T; Thu, 14 Jan 2021 09:37:37 +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 1kzz4E-0000QZ-3i for linux-arm-kernel@lists.infradead.org; Thu, 14 Jan 2021 09:37:23 +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 1CB3E1FB; Thu, 14 Jan 2021 01:37:19 -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 66C6C3F70D; Thu, 14 Jan 2021 01:37:16 -0800 (PST) Subject: Re: [PATCH v2 1/4] kasan, arm64: Add KASAN light mode To: Catalin Marinas References: <20210107172908.42686-1-vincenzo.frascino@arm.com> <20210107172908.42686-2-vincenzo.frascino@arm.com> <20210113171602.GD27045@gaia> From: Vincenzo Frascino Message-ID: <7125af39-2572-1b08-d223-51f4ea6e686b@arm.com> Date: Thu, 14 Jan 2021 09:40:57 +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: <20210113171602.GD27045@gaia> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210114_043722_287381_DC46F14C X-CRM114-Status: GOOD ( 20.84 ) 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 5:16 PM, Catalin Marinas wrote: > On Thu, Jan 07, 2021 at 05:29:05PM +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. If an async exception occurs, the >> arm64 core updates a register which is asynchronously detected the next >> time in which the kernel is accessed. > > What do you mean by "the kernel is accessed"? Also, there is no > "exception" as such, only a bit in a register updated asynchronously. So > the last sentence could be something like: > > In this mode, if a tag check fault occurs, the TFSR_EL1 register is > updated asynchronously. The kernel checks the corresponding bits > periodically. > > (or you can be more precise on when the kernel checks for such faults) > Yes, I agree, I will change it accordingly. What I wrote has a similar meaning but your exposition is more clear. >> KASAN requires a specific mode of execution to make use of this hw feature. >> >> Add KASAN HW light execution mode. > > Shall we call it "fast"? ;) > >> --- /dev/null >> +++ b/include/linux/kasan_def.h >> @@ -0,0 +1,25 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +#ifndef _LINUX_KASAN_DEF_H >> +#define _LINUX_KASAN_DEF_H >> + >> +enum kasan_arg_mode { >> + KASAN_ARG_MODE_DEFAULT, >> + KASAN_ARG_MODE_OFF, >> + KASAN_ARG_MODE_LIGHT, >> + KASAN_ARG_MODE_PROD, >> + KASAN_ARG_MODE_FULL, >> +}; >> + >> +enum kasan_arg_stacktrace { >> + KASAN_ARG_STACKTRACE_DEFAULT, >> + KASAN_ARG_STACKTRACE_OFF, >> + KASAN_ARG_STACKTRACE_ON, >> +}; >> + >> +enum kasan_arg_fault { >> + KASAN_ARG_FAULT_DEFAULT, >> + KASAN_ARG_FAULT_REPORT, >> + KASAN_ARG_FAULT_PANIC, >> +}; >> + >> +#endif /* _LINUX_KASAN_DEF_H */ > > I thought we agreed not to expose the KASAN internal but come up with > another abstraction. Maybe this was after you posted these patches. > Yes, indeed we agreed and I am going to change it in v3. The agreement temporally came after I posted v2 hence it is not reflected here. -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel