Re: i386 -> x86_64 cross compile failure (binutils bug?)

[Lee Revell]

On Sat, 2005-12-10 at 21:34 +0100, Xavier Bestel wrote:
> Le vendredi 09 décembre 2005 à 20:31 -0500, Lee Revell a écrit :
> > On Fri, 2005-12-09 at 23:43 +0100, Xavier Bestel wrote:
> > > Le vendredi 09 décembre 2005 à 13:50 -0500, Lee Revell a écrit :
> > > > I'm trying to build an x66-64 kernel on a 32 bit system (Ubuntu 5.10).
> > > > I added -m64 to the CFLAGS as per the gcc docs. 
> > > 
> > > Under debian 32bits with 64bits kernel, I just add -m64 somewhere in the
> > > main Makefile to rebuild my modules. Didn't try with a whole kernel
> > > though.
> > 
> > The bug seems to be that the kernel build system does not grok biarch
> > toolchains - it really insists on a separate toolchain for i386 and
> > x86_64 even though the situation can be handled with selective use of
> > -m64.  If I jsut add -m64 to everything then it fails when it gets to
> > the ia32 stuff.
> 
> Yes, you shouldn't compile host executables with -m64, obviously.
> 
> --- /usr/src/linux-headers-2.6.14-2/Makefile.old        2005-12-10 21:32:17.000000000 +0100
> +++ /usr/src/linux-headers-2.6.14-2/Makefile    2005-11-17 14:26:02.000000000 +0100
> @@ -352,7 +352,7 @@
> 
>  CFLAGS                 := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
>                    -fno-strict-aliasing -fno-common \
> -                  -ffreestanding
> +                  -ffreestanding -m64
>  AFLAGS         := -D__ASSEMBLY__
> 
>  export VERSION PATCHLEVEL SUBLEVEL EXTRAVERSION LOCALVERSION KERNELRELEASE \
> 
> 
> HTH,

This would break native 32 bit kernel builds.  Andi's patch seems to be
the correct solution.

Lee

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