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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 17574C2BA83 for ; Wed, 12 Feb 2020 17:36:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E07C821569 for ; Wed, 12 Feb 2020 17:36:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="WTUFnbqw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728728AbgBLRgg (ORCPT ); Wed, 12 Feb 2020 12:36:36 -0500 Received: from mail-ua1-f65.google.com ([209.85.222.65]:42559 "EHLO mail-ua1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727054AbgBLRgf (ORCPT ); Wed, 12 Feb 2020 12:36:35 -0500 Received: by mail-ua1-f65.google.com with SMTP id p2so1172323uao.9 for ; Wed, 12 Feb 2020 09:36:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oXC2J3nEK5SwOdFoK4ULqW0570rBTdySIYo3+gIlo9M=; b=WTUFnbqwYf+rL57s/FGxM1+vxE9Jz5IK7E+OqB1D8Yag+QT+LdUeuoco6oTC4zgy7L TKipBuXtB2O8hn6XUjmdUpdrUfke0F8SCdmbLI53UNP2BplyGiw6vXFuWmFYFzZtLQeN 5wpar/5ILukP9S05BShLrDSCKEPCKcsSH/oAGyElM1PsKMhn2zidyE008XJx5PD7dUMg n4j6E1083epW+BkViMtDeuVftqlXVyhEyjY2m1kZGGBAfrXmhWXYSRy7y6cbm8taKOCJ y3l8mKYES7s2h2SOYn+hKiFfdkCBn2+SUUTjhfBmJGbvU+drkZVcb4Ou3zqNKzp4BpKd nG4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oXC2J3nEK5SwOdFoK4ULqW0570rBTdySIYo3+gIlo9M=; b=Y4oVU/AhlH9eO/UCFQvp/cJnN2CK5oC+QwyLjIOd3y2w78QxBwNnnEpeH6OBNrVp+S g9udZ0OwZFV+VZpZHamNFprKEv4ow5AQbcxTPmkhgiecaeYRpX7oJfColCAlYhDlKNoH mcZxUX6yCc2UulhgSShtsmNtT/bc1AcTWnlMDEHfAYbK0Tu1G06zf5LXIVVnugJ388J8 uPL+AFNDUitpt4hqsIzr9NM/82aGdjvFAFUxSSlJIFeigz/ovRiMeftauY5+OsuVRB8O xGdZ+jJ8LvqqOKgqtZuakFQcTbKhTjleVJy86sGSQSJNZlOTQiGy9XJrY24Cs+Q9hxp1 gctA== X-Gm-Message-State: APjAAAXN9pm7NzArLEDnzH5EkHzS8GvXYe4GGnnvfQ1+fVQQrDEH5Op8 MdKZkejAOquzNJlOiMfXXJEVnoeCkisAoxrKi8dqGA== X-Google-Smtp-Source: APXvYqySnCPpjBgnelV684/U07lYpWTQs3A+aOrC5t4BnyXhAn03wUz7JH8o/EDUYvzcfRllMDnDJ3B306fqXtaeZDQ= X-Received: by 2002:ab0:422:: with SMTP id 31mr5283734uav.98.1581528994562; Wed, 12 Feb 2020 09:36:34 -0800 (PST) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200128184934.77625-1-samitolvanen@google.com> <63517cff-4bd6-bb6c-9a54-23de4f5fbb4a@arm.com> In-Reply-To: <63517cff-4bd6-bb6c-9a54-23de4f5fbb4a@arm.com> From: Sami Tolvanen Date: Wed, 12 Feb 2020 09:36:23 -0800 Message-ID: Subject: Re: [PATCH v7 00/11] add support for Clang's Shadow Call Stack To: James Morse Cc: Will Deacon , 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 , Kernel Hardening , linux-arm-kernel , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 11, 2020 at 5:57 AM James Morse wrote: > I found I had to add: > | KBUILD_CFLAGS := $(filter-out -ffixed-x18 $(CC_FLAGS_SCS), $(KBUILD_CFLAGS)) > > to drivers/firmware/efi/libstub/Makefile, to get this going. Ah, good catch! > I don't think there is much point supporting SCS for the EFIstub, its already isolated > from the rest of the kernel's C code by the __efistub symbol prefix machinery, and trying > to use it would expose us to buggy firmware at a point we can't handle it! Yes, fully agreed. > I can send a patch if its easier for you, It's not a problem, I will include a patch for this in v8. Sami