From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756720AbbEVHC6 (ORCPT ); Fri, 22 May 2015 03:02:58 -0400 Received: from mail-wi0-f175.google.com ([209.85.212.175]:37741 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756636AbbEVHCz (ORCPT ); Fri, 22 May 2015 03:02:55 -0400 Date: Fri, 22 May 2015 09:02:50 +0200 From: Ingo Molnar To: Arnaldo Carvalho de Melo Cc: Martin =?utf-8?B?TGnFoWth?= , linux-kernel@vger.kernel.org, Ingo Molnar , Paul Mackerras , Peter Zijlstra Subject: Re: [PATCH] perf: fix wrong DEBUG configuration Message-ID: <20150522070250.GA30715@gmail.com> References: <555B3D6F.6000301@suse.cz> <20150519140422.GJ13946@kernel.org> <555C871B.90900@suse.cz> <20150520131748.GC2955@kernel.org> <555C8C41.1080608@suse.cz> <20150520135333.GE2955@kernel.org> <20150520145506.GA15679@gmail.com> <555CB373.7090007@suse.cz> <20150521150536.GB13933@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20150521150536.GB13933@kernel.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Arnaldo Carvalho de Melo wrote: > Em Wed, May 20, 2015 at 06:16:51PM +0200, Martin Liška escreveu: > > On 05/20/2015 04:55 PM, Ingo Molnar wrote: > > >* Arnaldo Carvalho de Melo wrote: > > >>So the rule has been: What are the kernel requirements for the > > >>toolchain? tools/perf/ should build with that. > > > > > >So we could use -Og if it works, like Kbuild does it: > > > > > > KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) > > > > > >the 'cc-option' Make function does some magic of silently calling GCC > > >with that option and observing the result. > > > >See: > > > > scripts/Kbuild.include:cc-option = $(call try-run,\ > > > I am sorry, I did mistake in understanding of DEBUG variable. > > Following patch should be fixed, except missing auto-detection > > of -Og option. > > > > Unfortunately, following hunk does not work, no -Ox is added to CFLAGS? > > > > -- CFLAGS += -Og > > ++ CFLAGS += $(call cc-option,-Og,-O0) > > I don't know if we have this cc-option, perhaps Ingo is suggesting > we get it in tools/build/? Or include scripts/Kbuild.include and > then use it? > > I.e. we have checks to see if we can use, for instance > -fstack-protector-all, see tools/build/feature/Makefile, using this > cc-option thing, importing it from Kbuild would solve the issue at > hand in a definitive way and in line with what we have been > pursuing: to make the tools/ build system be based on Kbuild. So I'd suggest copying any necessary functions instead of outright including all of Kbuild in the tooling build system which creates non-trivial dependencies that is not necessarily tested as thoroughly on the kbuild side as on the tooling side. Thanks, Ingo