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=-7.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 5E3CDC43216 for ; Thu, 26 Aug 2021 12:16:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41B65608FE for ; Thu, 26 Aug 2021 12:16:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242506AbhHZMRD (ORCPT ); Thu, 26 Aug 2021 08:17:03 -0400 Received: from codesynthesis.com ([188.40.148.39]:49622 "EHLO codesynthesis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242415AbhHZMRC (ORCPT ); Thu, 26 Aug 2021 08:17:02 -0400 Received: from brak.codesynthesis.com (197-255-152-207.static.adept.co.za [197.255.152.207]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by codesynthesis.com (Postfix) with ESMTPSA id 4760D5F7CB; Thu, 26 Aug 2021 12:16:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codesynthesis.com; s=mail1; t=1629980173; bh=Wcp+spva27SDUMn5lh3p20Ss4YEIqbN0awnBME542Vc=; h=Date:From:To:Subject:Message-ID:MIME-Version:From; b=eaN58FnQWvzkHM296c9v+VrbfZQ49nAoJFz9UJX992sl6ORTlxe4hFsAr3kmjn3+t t5lEvmW+IVk4jEzoiuoeNBve+Q7EZho2ZKqCc+YHWky+7OHD4gqhxts5aFcXdUu8m7 Dt/Fa1lmZldSU/4Yqq4NDO/p7NvA9IWQyisNDs0bNN4ANOx074wGDTokR0YA4ACnu2 LKLauFGA+Ax0Q5OAJ+yYB1fC8Ogp1vvo1YbNQpSHPEcDPcn3XCwUbCSe3FIFj2lsGJ EeW5BL4FEolSf6EvSnLdd3szd8mf6pUEYEDBdaA+hzAiN9600nM1WcfKnNZT+FiZuc hfcHt8oR5T2cw== Received: by brak.codesynthesis.com (Postfix, from userid 1000) id F0E911A800C4; Thu, 26 Aug 2021 14:16:09 +0200 (SAST) Date: Thu, 26 Aug 2021 14:16:09 +0200 From: Boris Kolpackov To: Masahiro Yamada Cc: Linux Kbuild mailing list , "David S. Miller" , Jakub Kicinski , Jaroslav Kysela , Kalle Valo , Liam Girdwood , Luca Coelho , Mark Brown , Peter Ujfalusi , Takashi Iwai , ALSA Development Mailing List , Linux Kernel Mailing List , linux-wireless@vger.kernel.org, Networking Subject: Re: [PATCH] kconfig: forbid symbols that end with '_MODULE' Message-ID: References: <20210825041637.365171-1-masahiroy@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Code Synthesis User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Masahiro Yamada writes: > On Thu, Aug 26, 2021 at 12:42 AM Boris Kolpackov > wrote: > > > > Masahiro Yamada writes: > > > > > Kconfig (syncconfig) generates include/generated/autoconf.h to make > > > CONFIG options available to the pre-processor. > > > > > > The macros are suffixed with '_MODULE' for symbols with the value 'm'. > > > > > > Here is a conflict; CONFIG_FOO=m results in '#define CONFIG_FOO_MODULE 1', > > > but CONFIG_FOO_MODULE=y also results in the same define. > > > > > > fixdep always assumes CONFIG_FOO_MODULE comes from CONFIG_FOO=m, so the > > > dependency is not properly tracked for symbols that end with '_MODULE'. > > > > It seem to me the problem is in autoconf.h/fixdep, not in the Kconfig > > language. > > So, what is your suggestion for doing this correctly? > (of course without breaking the compatibility > because this is how the kernel is configured/built > for more than 20 years) Yes, I appreciate that fixing this properly may not be an option due to backwards-compatibility. How about then moving the check from the language closer to the place where it will actually be an issue. Specifically, can the error be triggered when we are about to write #define to autoconf.h and see that the name ends with _MODULE? > > I know you don't care, but I will voice my objection, for the record: > > Kconfig is used by projects other than the Linux kernel and some of > > them do not use the autoconf.h functionality. For such projects this > > restriction seems arbitrary and potentially backwards-incompatible. > > I am not sure what your worry is, but this check resides in > "if (modules_sym)" conditional, so projects using Kconfig but > not module functionality (e.g. buildroot) will not be affected. The Kconfig module semantics is actually general enough that a project other than the Linux kernel could reuse it. (I've written more on this possibility here[1]). [1] https://build2.org/libbuild2-kconfig/doc/build2-kconfig-manual.xhtml#lang-mod