linux-kernel - Re: config automatically switches from 32-bit to 64-bit for x86

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Message-ID: <20100602082039.GB5103@cr0.nay.redhat.com>
Date:	Wed, 2 Jun 2010 16:20:39 +0800
From:	Américo Wang <xiyou.wangcong@...il.com>
To:	Jaswinder Singh Rajput <jaswinderlinux@...il.com>
Cc:	Sam Ravnborg <sam@...nborg.org>,
	Christoph Hellwig <hch@...radead.org>,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	the arch/x86 maintainers <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Américo Wang <xiyou.wangcong@...il.com>,
	mmarek@...e.cz
Subject: Re: config automatically switches from 32-bit to 64-bit for x86

On Sat, May 29, 2010 at 10:49:25PM +0530, Jaswinder Singh Rajput wrote:
>Hello Sam and Américo,
>
>On Sat, May 29, 2010 at 4:49 PM, Sam Ravnborg <sam@...nborg.org> wrote:
>> On Fri, May 28, 2010 at 03:37:00AM +0530, Jaswinder Singh Rajput wrote:
>>> Hello Sam,
>>>
>>> On Fri, May 28, 2010 at 12:16 AM, Sam Ravnborg <sam@...nborg.org> wrote:
>>> > On Thu, May 27, 2010 at 11:49:16AM -0400, Christoph Hellwig wrote:
>>> >> On Thu, May 27, 2010 at 05:37:36AM +0530, Jaswinder Singh Rajput wrote:
>>> >> > Hello,
>>> >> >
>>> >> > I am trying to build 32 bit kernel image on 64-bit machine but after
>>> >> > 'make menuconfig' it automatically switches 32-bit to 64-bit.
>>> >> >
>>> >> > Is this a BUG or did intentionally.
>>> >>
>>> >> I think it's intentional, but I'm really annoyed by this behaviour.
>>> >
>>> > The request when we did the merge of 32 and 64 bit was that we
>>> > should continue to build 64bit kernels on 64 bit machines.
>>> > And likewise for 32bit.
>>> > Because this was what the users where used to.
>>> >
>>> > We could simplify metters by defining new rules.
>>> > As you suggest that uname on an intel box always resulted in ARCH=x86.
>>> > But then people would complain why a 32 bit kernel is default when
>>> > the box is 64 bit.
>>> >
>>> > Something like this:
>>> > [The escape chars align nicely in the patched Makefile]
>>> >
>>> >        Sam
>>> >
>>> > diff --git a/Makefile b/Makefile
>>> > index ebc8225..e7f97a5 100644
>>> > --- a/Makefile
>>> > +++ b/Makefile
>>> > @@ -161,10 +161,11 @@ 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/ \
>>> > -                                 -e s/arm.*/arm/ -e s/sa110/arm/ \
>>> > +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/ \
>>> > +                                 -e s/ppc.*/powerpc/ -e s/mips.*/mips/  \
>>> >                                  -e s/sh[234].*/sh/ )
>>> >
>>> >  # Cross compiling and selecting different set of gcc/bin-utils
>>> >
>>> >
>>>
>>> Thanks, this patch fixes the issue. Now 'make menuconfig' is following .config.
>>
>> If you think this is the right way to do things you can take it up
>> with the x86 maintainers.
>>
>> Although the patch touches only a generic file this is x86 specific.
>>
>
>Américo Wang, Do you mind handle this kconfig patch.
>


Sorry for the delay.

Usually Michal should take this patch. Cc'ing him.


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