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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 E3BE9C433E2 for ; Thu, 17 Sep 2020 09:03:48 +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 7280D20795 for ; Thu, 17 Sep 2020 09:03:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ATu3U/uW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7280D20795 Authentication-Results: mail.kernel.org; dmarc=none (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=Hp+Kn7k0E4oc8s3R0OLthXYwf46h/Q3TWBfs2qBmLPA=; b=ATu3U/uWjPAcX8JwyqW/6PgVS 5NOZrTugmkVavhO0FlSVaclKw7cRaxgR95Knzy91gXoe5z6pS+uGU8u1dwFJoU845ZPKuSyf/j+JL YJBdE5d1SiPnDVB3ZRBJAORWN+4Bzcq/l8OKxmeiXy+xIKdG4prKfGm9wZ4tuXrkn1VOqPceYZ2eP byG/+D2wrUWJQ8vaLFjO6wLowhjr8wicS3XmOAtUi60XHuG29mND64JVlTJyIJW94A9oUGGd2RhwY SiBH8TQPUUmPazEthwKJmPaFD+69SsnJig4FnSfKyYfrT7P4ObJ2BygoSRD4EUyTPX6F5S21ooRvX FhpoaYqmg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIpoL-00067N-Cw; Thu, 17 Sep 2020 09:02:37 +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 1kIpoJ-00066e-FN for linux-arm-kernel@lists.infradead.org; Thu, 17 Sep 2020 09:02:36 +0000 Received: from gaia (unknown [31.124.44.166]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B24B820770; Thu, 17 Sep 2020 09:02:32 +0000 (UTC) Date: Thu, 17 Sep 2020 10:02:30 +0100 From: Catalin Marinas To: Will Deacon Subject: Re: [PATCH v9 29/29] arm64: mte: Add Memory Tagging Extension documentation Message-ID: <20200917090229.GA10662@gaia> References: <20200904103029.32083-1-catalin.marinas@arm.com> <20200904103029.32083-30-catalin.marinas@arm.com> <20200917081107.GA29031@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200917081107.GA29031@willie-the-truck> 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-20200917_050235_583431_63B9DAA4 X-CRM114-Status: GOOD ( 20.86 ) 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: linux-arch@vger.kernel.org, libc-alpha@sourceware.org, Szabolcs Nagy , Andrey Konovalov , Kevin Brodsky , linux-mm@kvack.org, Andrew Morton , Vincenzo Frascino , Peter Collingbourne , Dave P Martin , 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 Thu, Sep 17, 2020 at 09:11:08AM +0100, Will Deacon wrote: > On Fri, Sep 04, 2020 at 11:30:29AM +0100, Catalin Marinas wrote: > > From: Vincenzo Frascino > > > > Memory Tagging Extension (part of the ARMv8.5 Extensions) provides > > a mechanism to detect the sources of memory related errors which > > may be vulnerable to exploitation, including bounds violations, > > use-after-free, use-after-return, use-out-of-scope and use before > > initialization errors. > > > > Add Memory Tagging Extension documentation for the arm64 linux > > kernel support. > > > > Signed-off-by: Vincenzo Frascino > > Co-developed-by: Catalin Marinas > > Signed-off-by: Catalin Marinas > > Acked-by: Szabolcs Nagy > > I'm taking this to mean that Szabolcs is happy with the proposed ABI -- > please shout if that's not the case! I think Szabolcs is still on holiday. To summarise the past threads, AFAICT he's happy with this per-thread control ABI but the discussion went on whether to expand it in the future (with a new bit) to synchronise the tag checking mode across all threads of a process. This adds some complications for the kernel as it needs an IPI to the other CPUs to set SCTLR_EL1 and it's also racy with multiple threads requesting different modes. Now, in the glibc land, if the tag check mode is controlled via environment variables, the dynamic loader can set this at process start while still in single-threaded mode and not touch it at run-time. The MTE checking can still be enabled at run-time, per mapped memory range via the PROT_MTE flag. This approach doesn't require any additional changes to the current patches. But it's for Szabolcs to confirm once he's back. > Wasn't there a man page kicking around too? Would be good to see that > go upstream (to the manpages project, of course). Dave started writing one for the tagged address ABI, not sure where that is. For the MTE additions, we are waiting for the ABI to be upstreamed. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel