Received: by 2002:ac0:a594:0:0:0:0:0 with SMTP id m20-v6csp2973672imm; Thu, 17 May 2018 00:53:02 -0700 (PDT) X-Google-Smtp-Source: AB8JxZp9d22vSmmAi+HbVUv4QunobFUfz5B6c66j66Mw8znYD7Fp0wiD3sdn6//NXd64dCXhkDpa X-Received: by 2002:a17:902:7844:: with SMTP id e4-v6mr4170738pln.296.1526543582930; Thu, 17 May 2018 00:53:02 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1526543582; cv=none; d=google.com; s=arc-20160816; b=wKmgjZaFZKsRILeZYVtCtzdlkku8X7pkhjI+V528wPTRIBbuzFB4xSB/i3iSYe2DIk K8GX0kH3HITTUGcKzGeNhykviZUBURiqrdvW8dQj2uJ4TMjWgbyL+JPsrh1yopGNGDIy 0QH+leoAFqGaf0WxL3RnNjVHxQW8FOok+fe0PjYqiiqX4gGNtXw+sWdV87jm0PrGQDVG dMCZMK+R2Ls+wAoZtqKwr2Rh/sr9iyOZyfWZVozgxjpSk+tnyNqiDHobbkGEETpMgTum SJFipcBQ0VosjxE7ADFkSeiGp8Jl6rVnSli9zAy/TMLacYeW9tkZeRmnw/+LweFlKHiZ qJjg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date :dkim-signature:arc-authentication-results; bh=hf8rcU1li/VKMqGBpQBQUxU51GtZSCYl6c/zoCFMAZg=; b=f39qRhJF5YNcyLrocExznNuxv0FK3qnbJEkzXP6x5IEGmCgRv/d6zdijcRSQrsaI0e 1StShPa7PQh6nQdAXhxkuZN+vnzExZqCPJb0HW0IUhgGTtfr/xVCKcT92EQHIWj/KT4N vRJVeYN5XC0+JPfQUSWYa/FRDQckq9qLSvy3MtV4xeluOg3F9Dd8gzz1gAEJmY7R3RpJ w0M1k0Hi0Y7/NC2VgDkgSjthr1A9V4KOBTcSpPNtcroiTdnOHozQvd7Je0t5Pbp/4WqQ uxXtypjChidXucV3JjOYLKm3QBLAEh3JfFCtu75gPvE9xmZSNKlScqYfjOrfIX8fbIYa 75Nw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=X3K1cvVD; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id x22-v6si4668860pfe.318.2018.05.17.00.52.48; Thu, 17 May 2018 00:53:02 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=X3K1cvVD; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752555AbeEQHwK (ORCPT + 99 others); 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 Received: by mail-pl0-f65.google.com with SMTP id az12-v6so2027035plb.8; Thu, 17 May 2018 00:52:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=hf8rcU1li/VKMqGBpQBQUxU51GtZSCYl6c/zoCFMAZg=; b=X3K1cvVDMll9U0K3rJVS9/LYMzbKmQDAh4pNCQ1asFQg2WGhWWgbG3WOYxJZfB5r82 ZeYcq7LJnnmA9kGWcL0i+1BHdm9XKFdaQaGz1e8pEQelyLHsuQw6/qesU54EdPGgPpB8 FSYloXIVq8ukThM+J0QmHh3gC8PhdCtDYXfjxqwPrv2rRcrYwGAtd9HmUmohem3yseAz pvDCKjvmPZ1IWMww8dy5uJVpiVT8IGdmYRONDwkhzuCMhfqdxd39SmcpgHaj+e5dWxaa q2BNouDNCSWbeMqo5VoUdVzUwNpj86cttwDibHJU/Sq+iKVXccMUUn6EvijbyJ1wZxts SMrw== 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=hf8rcU1li/VKMqGBpQBQUxU51GtZSCYl6c/zoCFMAZg=; b=KR+3ldHtHmlw2MRqdunvXbovYyt+4nWsSU+4nVG+lixQ8YeqeDjQcQDRK/E62E59CD dLcx0KNFXWY6QzY5YyDC2TXg5AKlqhBXCN43W77EsfKYkSCTFHufvKs+5djUHa+L8iY3 Ym2PP7uVju0TqlkBh7upqnhQ4GgLiyLnq+E0BO8CvyHWj9xYUTW0bgOEM4pB8g3j/JHX Z6hMppaIF9IVn2DODgW+dyp9jVvlwzIFWn8kTpJ4I5JUVg1m8eZ8rtaI2gyshSKR3gGu G2gl0aDtypWlamx0wwq4nuuZ1BYn31/gfdN4iK0bKpw3msouKpWm++Nxx+Ci3ypYl5cg 0xKA== X-Gm-Message-State: ALKqPwel3PoZF4Pp7BR8tE9Wtvn/wDPN7eExZJj/Ce70wR2fxqTTs0wa miilBm2n0sKyldT3GwlpgBo= X-Received: by 2002:a17:902:28a7:: with SMTP id f36-v6mr4207126plb.155.1526543528025; Thu, 17 May 2018 00:52:08 -0700 (PDT) Received: from roar.ozlabs.ibm.com (59-102-70-78.tpgi.com.au. [59.102.70.78]) by smtp.gmail.com with ESMTPSA id x8-v6sm8756676pfa.173.2018.05.17.00.52.03 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 17 May 2018 00:52:07 -0700 (PDT) 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 Precedence: bulk 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