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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 E1537C433DB for ; Wed, 10 Mar 2021 16:25:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACF9464FC5 for ; Wed, 10 Mar 2021 16:25:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231831AbhCJQYb (ORCPT ); Wed, 10 Mar 2021 11:24:31 -0500 Received: from mx2.suse.de ([195.135.220.15]:53716 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229602AbhCJQYE (ORCPT ); Wed, 10 Mar 2021 11:24:04 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 7CDBEABD7; Wed, 10 Mar 2021 16:24:03 +0000 (UTC) Date: Wed, 10 Mar 2021 17:24:02 +0100 From: Michal =?iso-8859-1?Q?Such=E1nek?= To: Masahiro Yamada Cc: linux-arm-kernel , Catalin Marinas , Will Deacon , Linux Kernel Mailing List Subject: Re: [PATCH] arm64: make STACKPROTECTOR_PER_TASK configurable. Message-ID: <20210310162402.GH6564@kitsune.suse.cz> References: <20210309123544.14040-1-msuchanek@suse.de> <20210309133523.GX6564@kitsune.suse.cz> <20210309151046.GZ6564@kitsune.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 10, 2021 at 04:07:00AM +0900, Masahiro Yamada wrote: > On Wed, Mar 10, 2021 at 12:10 AM Michal Suchánek wrote: > > > > On Tue, Mar 09, 2021 at 11:53:21PM +0900, Masahiro Yamada wrote: > > > On Tue, Mar 9, 2021 at 10:35 PM Michal Suchánek wrote: > > > > > > > > On Tue, Mar 09, 2021 at 10:22:36PM +0900, Masahiro Yamada wrote: > > > > > On Tue, Mar 9, 2021 at 9:35 PM Michal Suchanek wrote: > > > > > > > > > > > > When using dummy-tools STACKPROTECTOR_PER_TASK is unconditionally > > > > > > selected. This defeats the purpose of the all-enabled tool. > > > > > > > > > > > > Description copied from arm > > > > > > > > > > > > Cc: Masahiro Yamada > > > > > > Signed-off-by: Michal Suchanek > > > > > > > > > > > > > > > Could you explain what problem > > > > > this patch is trying to solve? > > > > > > > > The option cannot be disabled when compiler has the required capability. > > > > > > > > > Yes. > > > Currently, this symbol claims "def_bool y", > > > so there is no way to disable it. > > > > > > But, it comes from the nature of Kconfig in general. > > > > > > dummy-tools is completely unrelated here. > > > > dummy-tools makes all configuration options available in order to be > > able to author configuration files on system different from the one > > where the kernel is built. This prevents authoring a configuration file > > with this option disabled. > > > No. > dummy-tools enables as many $(cc-option, ...) > and $(shell, ...) as possible. That's it. > > > In my understanding, STACKPROTECTOR_PER_TASK > should not be user-configurable. > That is why 'def_bool y'. And that's wrong. Either it's a required copiler feature and then it should be always enabled. Or it is optional and then it should be possible to disable - one or the other. When it is optional you should be able to - (de) select in randconfig - test/bisect the old code path without crippling your toolchain - author configuration file that does not have the option enabled for build on system that uses older toolchain Thanks Michal