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=-5.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 C8ED7C433DB for ; Mon, 1 Feb 2021 03:21:40 +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 30EE764E25 for ; Mon, 1 Feb 2021 03:21:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 30EE764E25 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.microsoft.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:References: To:From:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pl+CCoFWmTmmCAG39AJmVy60CW1azeMcI012UQOp5JM=; b=jH/CcmqfgO2musg8eUYQOCdVM iwEjD9ElJ9QxoOb136kc8d0iWfJWndip0rD9MfefZGSKVGI0c7CqrFbzhvbBWK7PB4oV7+9ENeSwl uiDN0yaSpaQzbXPvV0U3zD5jjfsIK9hIBqh5DGP0a8Yjkjsq+hmwuxfij7YhTy0V/pzC8HYN0p/sz y0WJIOJhV5Vhk3VGBTAMbprmDJ0dqyhyjd8DqmITeopjcpNAsW14ZlGhHRn80dRY2bvs9vXj9h80r UmMThI/HnPbZgtz1hN9ql5UnGeNxJOgnay7L9HteXtDgL7lxNNs2RA3rGT2G5ThuUJMq5m8IPA2qd Ec932GYlw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6PlA-0000V1-1G; Mon, 01 Feb 2021 03:20:16 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6Pl6-0000R9-Po for linux-arm-kernel@lists.infradead.org; Mon, 01 Feb 2021 03:20:14 +0000 Received: from [192.168.254.32] (unknown [47.187.219.45]) by linux.microsoft.com (Postfix) with ESMTPSA id 6C2A620B7192; Sun, 31 Jan 2021 19:20:08 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 6C2A620B7192 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1612149609; bh=9D3JZS5Sq22g4xuiddpectS4Z8xVUROWzJ/Ic1ob8is=; h=Subject:From:To:Cc:References:Date:In-Reply-To:From; b=bg/I9Od/gbOaJuVFx8x+PFWZdTLLA5+WUjhD0lh5BtvNZ5VHrOrMHx2j0KoPco8CD hb/3S8im9STu6mxnsDky3OdDTYXs+Pf4Uupm7Y3WHaEtDXmdQxQsRJ88UehmUY7eLv xcJevzt0q+rw3jfiI1JjyA6noQ2q/Ws1yf0AKPMY= Subject: Re: [RFC PATCH 0/3] arm64: Implement reliable stack trace From: "Madhavan T. Venkataraman" To: Josh Poimboeuf , Mark Brown References: <20201012172605.10715-1-broonie@kernel.org> <13095563-ff6d-b806-1bf3-efde4383456e@linux.microsoft.com> <20210128142250.GC4537@sirena.org.uk> <20210128152649.6zin3hzim3etbv2p@treble> <4a934966-0460-459c-cce3-ca67f099d781@linux.microsoft.com> Message-ID: <30d538ab-2ffe-6df9-5217-62944b90806d@linux.microsoft.com> Date: Sun, 31 Jan 2021 21:20:07 -0600 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: <4a934966-0460-459c-cce3-ca67f099d781@linux.microsoft.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210131_222013_085514_650D1F41 X-CRM114-Status: GOOD ( 11.36 ) 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: Mark Rutland , Julien Thierry , Catalin Marinas , Miroslav Benes , 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 1/29/21 3:39 PM, Madhavan T. Venkataraman wrote: > - A separate register has to be reserved for holding the shadow stack > pointer. The compiler (gcc) has to be changed to not use this register for > other purposes. And we have to trust that there are no compiler bugs > in this area. All assembly code that currently uses this register for > anything needs to be reviewed and potentially changed. This includes > all inline assembly code. BTW, I believe clang uses x18 for the shadow > stack pointer register. Actually, if the stack and the shadow stack are allocated so that they are adjacent or at a fixed distance from each other, we don't need a separate register. We can compute parallel stack addresses from stack addresses by a simple calculation. So, this is not an issue. Madhavan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel