Re: Kconfig: ARCH=x86 causes wrong utsname.machine

[H. Peter Anvin]

Sam Ravnborg wrote:
> On Fri, Nov 16, 2007 at 07:20:15AM -0800, H. Peter Anvin wrote:
> > Andreas Herrmann wrote:
> > > The new ARCH=x86 kernel build causes weired machine strings on 32-bit.
> > > For a cross-compiled kernel I have
> > >
> > > 	 $ uname -m
> > > 	 x66_64
> > >
> > > For a kernel natively built on a 32 bit machine I have
> > >
> > > 	$ uname -m  
> > > 	x66
> > >
> > > Looking at the sources, I think that utsname->machine was initially
> > > set as "x86_64" and "x86", respectively.
> > > But in arch/x86/kernel/cpu/bugs.c in check_bugs() the second character
> > > is set to '6' on my K7.
> > >
> > > I think the right solution for that problem is to use "x86_64" as the
> > > machine name for 64-bit and to keep the old "i[3456]86" strings for
> > > 32-bit kernels.
> > Absolutely.  This would be userspace-visible ABI breakage.
>
> Any good suggestions here???
> UTS_MACHINE is set in top-level Makefile and if we specify
> make ARCH=x86
> we do not know if i386 or x86_&4 is correct until the configuration
> has been read.
>
> Should we report a "make ARCH=x86" as uname -m == x86??

That would break 5 years of a stable ABI.  I don't think that is even 
remotely feasible.

	-hpa
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