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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,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 AFD57C33CAF for ; Thu, 16 Jan 2020 18:10:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 89117214AF for ; Thu, 16 Jan 2020 18:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579198240; bh=8SPtXhgDABdtkfo2azlbC9YC/FrYRauKdCnSEeS0iXM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=UhYAYYVC3Ytvz5UAcIAqc7pOu4MQxXVTv9ba1FfwY74bSTFe1/dUt7ZI7VJ+TPq6l INrC8Og5ayundTDxhHNnn1/1g9DVbXVsHXEaAfQVF9M3KbP5S7CO1xJpBbaFfHaGea KxvHaWnAEul8Bs7hyEZcgrKJUpBgycm92hR1MYjA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395043AbgAPSKj (ORCPT ); Thu, 16 Jan 2020 13:10:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:53268 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393203AbgAPRhq (ORCPT ); Thu, 16 Jan 2020 12:37:46 -0500 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (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 9E60A246C6; Thu, 16 Jan 2020 17:37:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579196266; bh=8SPtXhgDABdtkfo2azlbC9YC/FrYRauKdCnSEeS0iXM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aoQqHHUeXgvXc3azh487blarI0nv3o9hiUY19N5hBxZdSanJP57l8QoyH8C3FOFjC fLQ8JocSkcenfCgyEQRD2Ifv3ibu/nrKUInfNAWFxvAldWYgdgJIldKkvBmgdKx2w0 hqYJXkIVAjhzdK2jGG3gP7p0i0lxRgVM6+nUpx58= Date: Thu, 16 Jan 2020 17:37:40 +0000 From: Will Deacon To: Sami Tolvanen Cc: Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland , Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 09/15] arm64: reserve x18 from general allocation with SCS Message-ID: <20200116173739.GA21396@willie-the-truck> References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> <20191206221351.38241-10-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191206221351.38241-10-samitolvanen@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 06, 2019 at 02:13:45PM -0800, Sami Tolvanen wrote: > Reserve the x18 register from general allocation when SCS is enabled, > because the compiler uses the register to store the current task's > shadow stack pointer. Note that all external kernel modules must also be > compiled with -ffixed-x18 if the kernel has SCS enabled. > > Signed-off-by: Sami Tolvanen > Reviewed-by: Nick Desaulniers > Reviewed-by: Kees Cook > --- > arch/arm64/Makefile | 4 ++++ > 1 file changed, 4 insertions(+) Acked-by: Will Deacon Will