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

[Ken Moffat]

On Fri, 9 Dec 2005, Lee Revell wrote:

> 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.  But the build fails
> with:
>
> $ make ARCH=x86_64
>  [...]
>  CC      init/initramfs.o
>  CC      init/calibrate.o
>  LD      init/built-in.o
>  CHK     usr/initramfs_list
>  CC      arch/x86_64/kernel/process.o
>  CC      arch/x86_64/kernel/signal.o
>  AS      arch/x86_64/kernel/entry.o
> arch/x86_64/kernel/entry.S: Assembler messages:
> arch/x86_64/kernel/entry.S:204: Error: cannot represent relocation type BFD_RELOC_X86_64_32S

 Unless ubuntu provides a biarch toolchain (and the fact gcc accepts 
'-m64' means nothing - use 'file' on init/built-in.o), you have to build 
a cross toolchain, (just binutils and gcc), put that on your path, and 
use

make ARCH=x86_64 CROSS_COMPILE=x86_64-pc-linux-gnu-

 so that the build will use x86_64-pc-linux-gnu-as and friends.  You 
should not need to mess with the CFLAGS.

Ken
--
 das eine Mal als Tragödie, das andere Mal als Farce