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=-5.4 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 E228BCA90AF for ; Tue, 12 May 2020 16:25:35 +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 B2842206B8 for ; Tue, 12 May 2020 16:25:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="RlAvaBI3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B2842206B8 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=atfmzJ1KSwNmFvNYi4/SwFOqX+3WzkorxW9qfXP4KuE=; b=RlAvaBI3U18xZ1 gUydY6DCV/s+GkSrjcNWgOxE+jHEvtI0HkIlAup5Tgi3aZ0RNw+Cqn3uja7CK9LCtUxTvRNV89HY5 hgxWVaCpMo5EBpuZGn6WMhvbGSFzCJLQbfIQphV4y6pL9P8yEeSaM4BvMfnXzG+oEe/bDpS7W4Jct VZRKqe4JwyBeAloP74+VR/Y3nxPaHjdyytn3TVXDtsXMt85uOYrI1MYR4ezWbnSwyy6WON/RQ0rMP v/8NrUNlr11mN9+sL6IdNUpFMLoU/MbMGq3zKQ860lLqu+ZcJOoAIftQzwjOHk1uPF7uv5y+QPCbV oJxgO6WG8JGVmRJLBMcA==; 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 1jYXio-0000rJ-Dl; Tue, 12 May 2020 16:25:34 +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 1jYXil-0000qd-15 for linux-arm-kernel@lists.infradead.org; Tue, 12 May 2020 16:25:32 +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 499191FB; Tue, 12 May 2020 09:25:26 -0700 (PDT) Received: from gaia (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D66653F305; Tue, 12 May 2020 09:25:24 -0700 (PDT) Date: Tue, 12 May 2020 17:25:21 +0100 From: Catalin Marinas To: Peter Collingbourne Subject: Re: [PATCH v5] arm64: Expose FAR_EL1 tag bits in sigcontext Message-ID: <20200512162520.GE14943@gaia> References: <20200507175713.162890-1-pcc@google.com> <20200508020106.136652-1-pcc@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200508020106.136652-1-pcc@google.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-20200512_092531_114876_206D7D0D X-CRM114-Status: GOOD ( 11.72 ) 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 , Will Deacon , Dave Martin , 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 Thu, May 07, 2020 at 07:01:06PM -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 fault_addr_top_byte_context in sigcontext > (similar to the existing esr_context), and store the tag bits of FAR_EL1 there. > > [1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html > > Signed-off-by: Peter Collingbourne It looks alright to me. Reviewed-by: Catalin Marinas _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel