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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1748DC433F5 for ; Fri, 28 Jan 2022 22:49:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351770AbiA1Wtj (ORCPT ); Fri, 28 Jan 2022 17:49:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348293AbiA1Wt3 (ORCPT ); Fri, 28 Jan 2022 17:49:29 -0500 Received: from mail-lf1-x132.google.com (mail-lf1-x132.google.com [IPv6:2a00:1450:4864:20::132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B00D0C061747 for ; Fri, 28 Jan 2022 14:49:28 -0800 (PST) Received: by mail-lf1-x132.google.com with SMTP id x11so14667906lfa.2 for ; Fri, 28 Jan 2022 14:49:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Ga12vASgQepzopTf7itk5qo6jciiWvEYo54yaueBv/k=; b=ocuHiLSMSPTflZxrNNESvCIQ9i+7KDA5CgbR62QaQKXXDLgjYsHYlv8V7w7m89YSBv uqDFU8pu0wkTuGojbwMOm4xC4j81ouCZqMQUv4ylul1TzqWYa5Ej6sz/dpO4Xx6Tk5av UXItrbB9Ml1gsjXRDAWJ85uAnmftgLgl+I/3ZPdhD7ISL1Rx/oofWx6I5gZvy0O+ebnd CCtov4e6Wjt3VZbONDqtD2zgyJK7ekvkOfRukUUMmiEIf1WPwG/vQtQg51YleVk2+yru vtbMsL+rLA3DMH7e2gqooF1lNdWj9PV5SMlT604dQ55IYytTAWSziScWu9bvSVp9McF6 OPmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Ga12vASgQepzopTf7itk5qo6jciiWvEYo54yaueBv/k=; b=QorpWZaqE8SzCH7eyr36FEa/BJz28/HJLAN2Q2sBATtJIWWAi6Zj03zsZDggF3Ri9d HXhfYIFsSbEnf2Sy+c906gOQu0DvRpqOzwTl+LJwikAEYrQ9tqPl2+8yBOZb5Xx0voNE p/9ca2otudqK7srTswZrpbGXPkp4tX5fxtoE9FczzufadkEA5Q0eTyMKD29UpLgYoX0Y lLdVGuI0UzAvx4zBRtU6LqCPpOiiN+5v+ESuc/WSEdmOw1i9tHOtWveQ/pbgMycEqcLf tuZFl71B73xGxhSlhB1dHEchHhLeMxC9jCOLVsk1Ebi0/8ZrscZsLYw1VE/JRlIzEy3R hSOw== X-Gm-Message-State: AOAM531Ax41pQslY8E5fS6lux4zzev4/D5liDZrsrTO5Hfi52eNx37+y ogIaBOAVbyhuaQkub3MQUUuzvZK8PAgzx3srHEQRPs3u5hTHQA== X-Google-Smtp-Source: ABdhPJzaJFI+R0ILoPy/Efjd+HHvfSdGQyGuwezXUpAsCFmnl8paU8d50L8ZlP2AF/lXoKPXGH4nExxQp3vxfXwFFHg= X-Received: by 2002:a05:6512:3ba5:: with SMTP id g37mr7601124lfv.651.1643410166929; Fri, 28 Jan 2022 14:49:26 -0800 (PST) MIME-Version: 1.0 References: <20220112224342.958358-1-quic_eberman@quicinc.com> <20220128220841.3222637-1-quic_eberman@quicinc.com> <20220128224528.f7ejzw55t6kfefmm@google.com> In-Reply-To: <20220128224528.f7ejzw55t6kfefmm@google.com> From: Nick Desaulniers Date: Fri, 28 Jan 2022 14:49:15 -0800 Message-ID: Subject: Re: [PATCH v2] kbuild: Add environment variables for userprogs flags To: Elliot Berman Cc: Masahiro Yamada , Michal Marek , Nathan Chancellor , Matthias Maennich , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Fangrui Song Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 28, 2022 at 2:45 PM Fangrui Song wrote: > > On 2022-01-28, Elliot Berman wrote: > >Allow additional arguments be passed to userprogs compilation. > >Reproducible clang builds need to provide a sysroot and gcc path to > >ensure same toolchain is used across hosts. KCFLAGS is not currently > >used for any user programs compilation, so add new USERCFLAGS and > >USERLDFLAGS which serves similar purpose as HOSTCFLAGS/HOSTLDFLAGS. > > > >Specifically, I'm trying to force CC_CAN_LINK to consistently fail in > >an environment where a user sysroot is not specifically available. > >Currently, Clang might automatically detect GCC installation on hosts > >which have it installed to a default location in /. With addition of > >these environment variables, you can specify flags such as: > > > >$ make USERCFLAGS=--sysroot=/dev/null USERLDFLAGS=-Wl,--sysroot=/dev/null > > > >to force sysroot detection to fail. > > -Wl,--sysroot=/dev/null => --sysroot > > As I mentioned in > https://lore.kernel.org/all/20220128031549.w5a4bilxbkppagfu@google.com/ > -Wl,--sysroot=/dev/null does not suppress search paths like -L/lib . In that case, Elliot, can you please test whether USERLDFLAGS is necessary to be specified AT ALL? Maybe we can drop that addition from this patch if so? -- Thanks, ~Nick Desaulniers