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=-5.2 required=3.0 tests=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=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 57B77C43331 for ; Fri, 27 Mar 2020 11:39:13 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 24F812072F for ; Fri, 27 Mar 2020 11:39:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="oNRaC8X1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24F812072F 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+infradead-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=bombadil.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=NzlrOL8e0KtKWqZ72yQHXg3zBIFcvhR0HTOVkhLVA88=; b=oNRaC8X1UrfoG7 u4XLGDX+sud7bCZATOa5bsxzrWLGWj0Xk8jrxmVGGYYCkTZvmWjxDZOCUrAwNUXuul8TAIW9dNANv QDkD1ac98azMJxHidGrQ/fPFHUJ/q9WXUe1LjwNPTgaMF6bZTKsRbCpHQInzin8p9xOnBIYCW9V2v nhsMdGRk0YbZv45t20SuBhli0yof2JSQVUXIBnHzkXAy1f8zFdTjwsHATDwubyavGFnTdLqJC9CLB dOUnkRQBdcHfpijf7s1QnDjMPtTT7Jy7fZz04NxSplWbkpkNqSwsukoTukeAwe8F4CcLhVRbq8Gul JIcrTE7FP3jE7gUOZc9g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHnKP-0008IG-T2; Fri, 27 Mar 2020 11:39:09 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHnKM-0008Hd-97 for linux-arm-kernel@lists.infradead.org; Fri, 27 Mar 2020 11:39:08 +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 F12F430E; Fri, 27 Mar 2020 04:39:03 -0700 (PDT) Received: from mbp (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A8B253F71E; Fri, 27 Mar 2020 04:39:02 -0700 (PDT) Date: Fri, 27 Mar 2020 11:39:00 +0000 From: Catalin Marinas To: Will Deacon Subject: Re: [PATCH v2] arm64: Expose original FAR_EL1 value in sigcontext Message-ID: <20200327113859.GA18117@mbp> References: <20200312171755.177743-1-pcc@google.com> <20200325174001.234803-1-pcc@google.com> <20200326164538.GC26987@mbp> <20200327075655.GA32241@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200327075655.GA32241@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-20200327_043906_369006_9E4B103A X-CRM114-Status: GOOD ( 17.30 ) 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: Andrey Konovalov , Kevin Brodsky , Kostya Serebryany , Evgenii Stepanov , Vincenzo Frascino , Peter Collingbourne , Linux ARM , Richard Henderson Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Mar 27, 2020 at 07:56:56AM +0000, Will Deacon wrote: > On Thu, Mar 26, 2020 at 04:45:39PM +0000, Catalin Marinas wrote: > > On Wed, Mar 25, 2020 at 10:40:01AM -0700, Peter Collingbourne wrote: > > > The kernel currently clears the tag bits (i.e. bits 56-63) in the fault > > > address exposed via siginfo.si_addr and sigcontext.fault_address. However, > > > the tag bits may be needed by tools in order to accurately diagnose > > > memory errors, such as HWASan [1] or future tools based on the Memory > > > Tagging Extension (MTE). > > > > > > We should not stop clearing these bits in the existing fault address > > > fields, because there may be existing userspace applications that are > > > expecting the tag bits to be cleared. Instead, create a far_context in > > > sigcontext (similar to the existing esr_context), and store the original > > > value of FAR_EL1 (including the tag bits) there. > > > > > > [1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html > > > > > > Signed-off-by: Peter Collingbourne > > > > The patch looks fine. However, I wouldn't queue it for 5.7, it's too > > close to the merging window and I'd like it to sit in linux-next for a > > bit. Unless there are other comments, it looks fine to me for -rc8. > > You mean 5.8? Yes. > I'm also a bit surprised not to see a docs update, given that > we talk about the general lack of tags in siginfo_t towards the end of > Documentation/arm64/tagged-pointers.rst Good point. It's worth adding this to the tagged-pointers.rst document since the only use of the raw FAR_EL1 is for tagged pointers. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel