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=-7.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,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 0228FC433E0 for ; Fri, 22 Jan 2021 17:46:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6D3A23A68 for ; Fri, 22 Jan 2021 17:45:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729693AbhAVRpk (ORCPT ); Fri, 22 Jan 2021 12:45:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:52692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729636AbhAVRpG (ORCPT ); Fri, 22 Jan 2021 12:45:06 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2A71E23A68; Fri, 22 Jan 2021 17:44:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611337462; bh=Fbw7hbg4eFinWbI+ufZKhLlJam1o9Uua400X/NfxFCE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tX8UzS/eD1cr7yrQUJIL18lkdaJbV4NkcQq6ejfOaQuFv2hdvx2Dk2NxHKCELL+tm gB5LH/E2jHzoODl+l5pC9LnH4BX3C8cNb+HMFLlzVvs2z9GeO5N2HamAgsoag69397 xM9GyS+b9vSwcmDLtnJqh2UqiyZe/LtRxD0SvL15ZIehVGJ/1nwh5tcC5zdIfDSuTg UA9DbMktYrr+7xDQjw+RV13CbEuXa78wQrGoTQX5eF7DP8NsrLjY+eWMkokeOdrx4s IdtW124T7EH7s2t0LQV2LfAo+FSU6r0qSwCHNJSxp+ByPvpWcJ+fa8vzlsM7HV6JE0 Wj6V1sT2vNblg== Date: Fri, 22 Jan 2021 17:43:42 +0000 From: Mark Brown To: Josh Poimboeuf Cc: Ard Biesheuvel , Peter Zijlstra , Julien Thierry , Linux Kernel Mailing List , Linux ARM , Catalin Marinas , Will Deacon , Masahiro Yamada , Kees Cook , Michal Marek , Mark Rutland , linux-efi , linux-hardening@vger.kernel.org, live-patching@vger.kernel.org Subject: Re: [RFC PATCH 00/17] objtool: add base support for arm64 Message-ID: <20210122174342.GG6391@sirena.org.uk> References: <20210120173800.1660730-1-jthierry@redhat.com> <186bb660-6e70-6bbf-4e96-1894799c79ce@redhat.com> <20210121185452.fxoz4ehqfv75bdzq@treble> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="z9ECzHErBrwFF8sy" Content-Disposition: inline In-Reply-To: <20210121185452.fxoz4ehqfv75bdzq@treble> X-Cookie: 98% lean. User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org --z9ECzHErBrwFF8sy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Jan 21, 2021 at 12:54:52PM -0600, Josh Poimboeuf wrote: > 2) The shadow stack idea sounds promising -- how hard would it be to > make a prototype reliable unwinder? In theory it doesn't look too hard and I can't see a particular reason not to try doing this - there's going to be edge cases but hopefully for reliable stack trace they're all in areas where we would be happy to just decide the stack isn't reliable anyway, things like nesting which allocates separate shadow stacks for each nested level for example. I'll take a look. --z9ECzHErBrwFF8sy Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmALDs0ACgkQJNaLcl1U h9D+zggAgtOONPllLfslr6X/wB/43FjYYsgGfKtPctsQgrbSMbqrDXOu8z6jJTT9 WfzvJoic373/eZzXRIu2mQIAjMNLC9bsYKFSjL3YdM4QN17TuvxyawY6GTMi+7HK p+wANJD/JE0Hze6QtsM4uyVUd3t16oHVTaJ7wn7bc9CThv4wtj7BMD7Lrj98OGJ2 BDwZKSWLroBkd1DBUdEnS1ROAlVq/QFvZ6VcqbrFobcsGsSoBiC9XgpEYzF68cW9 ywYhjF1o3mdhCtJF2actzFz6at/aWkfGWa0O93EZsRjON6DEklJLMVBf2ylexGBY MoROeAM/bDf4oj3hrKxGNKy4Zm+C6w== =6hN/ -----END PGP SIGNATURE----- --z9ECzHErBrwFF8sy--