From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752891Ab1GaVry (ORCPT ); Sun, 31 Jul 2011 17:47:54 -0400 Received: from mail-pz0-f42.google.com ([209.85.210.42]:37387 "EHLO mail-pz0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752656Ab1GaVrt convert rfc822-to-8bit (ORCPT ); Sun, 31 Jul 2011 17:47:49 -0400 MIME-Version: 1.0 In-Reply-To: <1311986969.20983.52.camel@i7.infradead.org> References: <1306707270.2029.377.camel@i7.infradead.org> <20110530072300.GA9802@elte.hu> <1306745835.2029.389.camel@i7.infradead.org> <20110530104231.GF17821@elte.hu> <20110530104656.GA19532@elte.hu> <20110530105809.GA20133@elte.hu> <1A4DB87D-9B32-44C0-B7C9-47A003CABD96@mit.edu> <20110530195545.GG2890@dhcp-172-31-194-241.cam.corp.google.com> <1306795186.2029.459.camel@i7.infradead.org> <1306856937.27477.3.camel@i7.infradead.org> <4E0495F4.7080300@suse.cz> <1311986969.20983.52.camel@i7.infradead.org> Date: Sun, 31 Jul 2011 17:47:48 -0400 Message-ID: Subject: Re: [PATCH v3] x86, kconfig: Default to ARCH=x86 to avoid overriding CONFIG_64BIT From: Arnaud Lacombe To: David Woodhouse Cc: Michal Marek , "Ted Ts'o" , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, hpa@zytor.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Fri, Jul 29, 2011 at 8:49 PM, David Woodhouse wrote: > I *frequently* waste a bunch of time when I take a 32-bit .config from a > test machine and try to build it on a faster 64-bit system, and its > existing setting of CONFIG_64BIT=n gets *changed* to match the build host. > > This is because the default setting for $ARCH when discovered from > 'uname' is one of the legacy pre-x86-merge values (i386 or x86_64), > which effectively force the setting of CONFIG_64BIT to match. We should > default to ARCH=x86 instead, finally completing the merge that we > started so long ago. > AFAICS, `scripts/mkcompile_h' ends up using ${ARCH} to build UTS_MACHINE, so it ends up being directly visible to userland. I would wonder which userland application (both script and binaries), relying on this interface, you are breaking... - Arnaud > This patch preserves the behaviour of the legacy ARCH settings for commands > such as: > >   make ARCH=x86_64 randconfig >   make ARCH=i386 randconfig > > ... although since my commit "Enable 'make CONFIG_FOO=y oldconfig'" those > would be better expressed as: > >   make CONFIG_64BIT=y randconfig >   make CONFIG_64BIT=n randconfig > > ... since that is a more generic way to set *any* config option, and > there's no other technical reason to keep the legacy ARCH values around > any more just to achieve that purpose; they could be removed at any > time. > > Signed-off-by: David Woodhouse > Link: http://lkml.kernel.org/r/1306707270.2029.377.camel@i7.infradead.org > --- > v2: Explicitly turn off CONFIG_64BIT in i386_defconfig. The default for >    CONFIG_64BIT has *changed* (from n to y) for ARCH=x86, so it needs to >    be explicitly turned off or 'make i386_defconfig' will give you 64-bit. > v3: Same patch as before; just updated changelog. > >  Makefile                        |    3 ++- >  arch/x86/Kconfig                |    2 +- >  arch/x86/Makefile               |    4 ++++ >  arch/x86/configs/i386_defconfig |    1 + >  4 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/Makefile b/Makefile > index d018956..303df9b 100644 > --- a/Makefile > +++ b/Makefile > @@ -165,7 +165,8 @@ export srctree objtree VPATH >  # then ARCH is assigned, getting whatever value it gets normally, and >  # SUBARCH is subsequently ignored. > > -SUBARCH := $(shell uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \ > +SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x86/ \ > +                                 -e s/sun4u/sparc64/ \ >                                  -e s/arm.*/arm/ -e s/sa110/arm/ \ >                                  -e s/s390x/s390/ -e s/parisc64/parisc/ \ >                                  -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \ > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 153aa6f..9467fdd 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -1,7 +1,7 @@ >  # Select 32 or 64 bit >  config 64BIT >        bool "64-bit kernel" if ARCH = "x86" > -       default ARCH = "x86_64" > +       default ARCH != "i386" >        ---help--- >          Say yes to build a 64-bit kernel - formerly known as x86_64 >          Say no to build a 32-bit kernel - formerly known as i386 > diff --git a/arch/x86/Makefile b/arch/x86/Makefile > index b02e509..94c2d8c 100644 > --- a/arch/x86/Makefile > +++ b/arch/x86/Makefile > @@ -2,7 +2,11 @@ > >  # select defconfig based on actual architecture >  ifeq ($(ARCH),x86) > +  ifeq ($(shell uname -m),x86_64) > +        KBUILD_DEFCONFIG := x86_64_defconfig > +  else >         KBUILD_DEFCONFIG := i386_defconfig > +  endif >  else >         KBUILD_DEFCONFIG := $(ARCH)_defconfig >  endif > diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig > index 2bf18059f..5f96c1c 100644 > --- a/arch/x86/configs/i386_defconfig > +++ b/arch/x86/configs/i386_defconfig > @@ -1,3 +1,4 @@ > +# CONFIG_64BIT is not set >  CONFIG_EXPERIMENTAL=y >  # CONFIG_LOCALVERSION_AUTO is not set >  CONFIG_SYSVIPC=y > -- > 1.7.6 > > > > -- > dwmw2 > >