From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cpsmtpb-ews02.kpnxchange.com ([213.75.39.5]:60747 "EHLO cpsmtpb-ews02.kpnxchange.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756488AbaICVLh (ORCPT ); Wed, 3 Sep 2014 17:11:37 -0400 Message-ID: <1409778695.5546.55.camel@x220> Subject: Re: [PATCH v2 4/4] kconfig: link CONFIG_CROSS_COMPILE with environment variable From: Paul Bolle Date: Wed, 03 Sep 2014 23:11:35 +0200 In-Reply-To: <20140901071639.28909.88888.stgit@zurg> References: <20140901065916.28909.35097.stgit@zurg> <20140901071639.28909.88888.stgit@zurg> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Konstantin Khlebnikov Cc: Michal Marek , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Geert Uytterhoeven Hi Konstantin, On Mon, 2014-09-01 at 11:16 +0400, Konstantin Khlebnikov wrote: > Cross-compiler tool prefix can be set in command line, in the environment > variable CROSS_COMPILE or in config file, in option CONFIG_COROSS_COMPILE. > Also some arch/*/Makefile provides default value. > > This patch links config option CONFIG_CROSS_COMPILE and variable CROSS_COMPILE > in both directions: environment/command line has higher priority and updates > value saved in the config file, config option acts as default value for it. > > This is especially useful together with option O=dir which allows to create > separate directory for each target architecture and kernel flavor: > > # make O=build/arm ARCH=arm CROSS_COMPILE=arm-none-eabi- defconfig > # make -C build/arm > > Signed-off-by: Konstantin Khlebnikov I have only had a quick glance at this series. Just a quick question to help me understand where it is going. Would this patch mean that, if a (def)config file has both ARCH and CROSS_COMPILE set, one could use that (def)config file and invoke "make $whatever_target" and expect it to do the right thing (provided a suitable cross compiler is installed)? This implies cross compiler prefixes are standardized across distributions, I guess. Maybe they're not. > --- > Makefile | 6 +++++- > init/Kconfig | 1 + > 2 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/Makefile b/Makefile > index f648405..1044f40 100644 > --- a/Makefile > +++ b/Makefile > @@ -263,7 +263,11 @@ endif > # "make" in the configured kernel build directory always uses that. > # Default value for CROSS_COMPILE is not to prefix executables > # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile > -CROSS_COMPILE ?= $(CONFIG_CROSS_COMPILE:"%"=%) > +ifndef CROSS_COMPILE > + CROSS_COMPILE := $(shell $(srctree)/scripts/config \ > + --file $(KBUILD_OUTPUT)$(KCONFIG_CONFIG) \ > + --if-undef "" --state "CROSS_COMPILE") > +endif > > # Architecture as present in compile.h > UTS_MACHINE := $(ARCH) > diff --git a/init/Kconfig b/init/Kconfig > index e84c642..1c2f621 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -47,6 +47,7 @@ config INIT_ENV_ARG_LIMIT > > config CROSS_COMPILE > string "Cross-compiler tool prefix" > + option env="CROSS_COMPILE" > help > Same as running 'make CROSS_COMPILE=prefix-' but stored for > default make runs in this kernel build directory. You don't > Paul Bolle