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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 182F2C433DF for ; Fri, 26 Jun 2020 20:37:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E66712075D for ; Fri, 26 Jun 2020 20:37:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="LasIkQVy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725900AbgFZUhD (ORCPT ); Fri, 26 Jun 2020 16:37:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725832AbgFZUhC (ORCPT ); Fri, 26 Jun 2020 16:37:02 -0400 Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E37CEC03E97B for ; Fri, 26 Jun 2020 13:37:02 -0700 (PDT) Received: by mail-pl1-x641.google.com with SMTP id g17so4659520plq.12 for ; Fri, 26 Jun 2020 13:37:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=nt/218p7v20WGusEjZTRWNofL1UTU7wXJpxnIwWbqck=; b=LasIkQVyh7YOVLhmmWjNknLdRMiIhvmSIsX6upZZEv19wZkBLTDXThFG+IoJtTQ1DK zcl6LQej91z8gS9IaBIyAs1OvHj/0GDMvNCjRsmmphnLs25aUBJeB2/1LelcaqiXTaN0 pdUtgwESOtklxyeVHayu+6UmjFTjibUVnEUdE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=nt/218p7v20WGusEjZTRWNofL1UTU7wXJpxnIwWbqck=; b=KBZ4Jx3GrFz3aHZdwhiQbO2o1Ojvg9mGXeV+EZaVAwx4MoJdGur7vT4FKGb5It42hg w4vOtewug+CTEg7+CAs/mEp4UjshpCjRu6Xywfa4NA8Bw7+pqF9Ks08cVhUpUIX5XzhD sC5FanNsZ9DD6bG3nlITDEPDWM1zMxuR6b3067bttuVinXAA9kfyCYclXNzZu52sECkd 9Lmj9WAn4Y+Pvj9slPxbu7+Ixa1UJxNrzeKP0f0Wnv+dCcQJHagx7UVlKaXxHTBcp4Dh Lc8a3I+VpztcRIUgCxJjPH1jUujYKXCSLbN/HihoQ6KLDhCEchQEsyLi3vv0LOx7iIDc geiA== X-Gm-Message-State: AOAM530/aefcAbKgguTG54VTBlsMFve9q49wbah8kOFayrbtwwNypODT dhk1VdwhXtj74k903Pyc+R/1d1B1lTE= X-Google-Smtp-Source: ABdhPJzRjBzSEkMCU+0/yeMZIBtu9OcMQa8md9tY/FMmEyvlXIZhD94nhAwv0QyEtFY0fbb9xk24ng== X-Received: by 2002:a17:902:7896:: with SMTP id q22mr3972740pll.338.1593203822398; Fri, 26 Jun 2020 13:37:02 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id r8sm27166377pfq.16.2020.06.26.13.37.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jun 2020 13:37:01 -0700 (PDT) Date: Fri, 26 Jun 2020 13:37:00 -0700 From: Kees Cook To: Nick Desaulniers Cc: Masahiro Yamada , Linux Kbuild mailing list , clang-built-linux , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , linux-efi , LKML Subject: Re: [PATCH 1/2] kbuild: remove cc-option test of -fno-stack-protector Message-ID: <202006261331.3A94DB7@keescook> References: <20200626185913.92890-1-masahiroy@kernel.org> <202006261319.F130204@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On Fri, Jun 26, 2020 at 01:25:27PM -0700, Nick Desaulniers wrote: > Ah, right. Thanks for pointing that out. I'm still curious if the > CFLAGS_.o rules get appended or overwrite all flags for that > translation unit? CFLAGS_file.o gets appended to the CFLAGS. For example, after my updated patch[1], the command line for syscall_64.o looks like this: gcc -Wp,-MMD,arch/x86/entry/.syscall_64.o.d -nostdinc -isystem \ ... -Wframe-larger-than=2048 -fstack-protector-strong \ ... -fno-stack-protector -Wno-override-init \ -DKBUILD_MODFILE='"arch/x86/entry/syscall_64"' \ -DKBUILD_BASENAME='"syscall_64"' \ -DKBUILD_MODNAME='"syscall_64"' \ -c -o arch/x86/entry/syscall_64.o \ arch/x86/entry/syscall_64.c -Kees [1] https://lore.kernel.org/lkml/202006261333.585319CA6B@keescook/ -- Kees Cook