From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752573AbeEQHwK (ORCPT ); Thu, 17 May 2018 03:52:10 -0400 Received: from mail-pl0-f65.google.com ([209.85.160.65]:41816 "EHLO mail-pl0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752243AbeEQHwI (ORCPT ); Thu, 17 May 2018 03:52:08 -0400 X-Google-Smtp-Source: AB8JxZrlUbiUmJeXYYjianfoqsC+7Heq1dVoPqU4WHfhTbJfvjIYtjoFyMU0mpcSMaBg2UAesNAbQw== Date: Thu, 17 May 2018 17:51:56 +1000 From: Nicholas Piggin To: Masahiro Yamada Cc: linux-kbuild@vger.kernel.org, Linus Torvalds , Sam Ravnborg , Ulf Magnusson , "Luis R . Rodriguez" , linux-kernel@vger.kernel.org, Kees Cook , Emese Revfy , x86@kernel.org Subject: Re: [PATCH v4 00/31] kconfig: move compiler capability tests to Kconfig Message-ID: <20180517175156.4c4246f6@roar.ozlabs.ibm.com> In-Reply-To: <1526537830-22606-1-git-send-email-yamada.masahiro@socionext.com> References: <1526537830-22606-1-git-send-email-yamada.masahiro@socionext.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 17 May 2018 15:16:39 +0900 Masahiro Yamada wrote: > [Introduction] > > The motivation of this work is to move the compiler option tests to > Kconfig from Makefile. A number of kernel features require the > compiler support. Enabling such features blindly in Kconfig ends up > with a lot of nasty build-time testing in Makefiles. If a chosen > feature turns out unsupported by the compiler, what the build system > can do is either to disable it (silently!) or to forcibly break the > build, despite Kconfig has let the user to enable it. By moving the > compiler capability tests to Kconfig, Kconfig entries will be visible > only when they are available. > > [Major Changes in V4] Do you have a git tree for v4? I can test it with the powerpc patches. The new scripting capability in kconfig has allowed us to already improve the config process on powerpc: https://marc.info/?l=linuxppc-embedded&m=152648110727868&w=2 I'm sure there's more clever things we can do with it but I haven't had time to think about it yet. One thing that comes to mind is that It might be nice to show the option as disabled, then the user could upgrade their compiler to get the options they want. Anyway v3 worked fine for me, the documentation is really nice, I could implement the above patch without any problem despite being a kbuild dummy. Thanks for the series, ack from me. Thanks, Nick