Re: Building GRUB on platforms without ELF support

[Christian Franke]

Marco Gerards wrote:
> Robert Millan <address@hidden> writes:
>
>   
> > On Fri, Nov 16, 2007 at 11:58:14PM +0100, Christian Franke wrote:
> >     
> > > ...
> > > For specific conversions, fixing this in objcopy itself is easy. But 
> > > there is not much chance that such pragmatic patches will be accepted 
> > > upstream.
> > > (http://sourceware.org/ml/binutils/2007-10/threads.html#00302)
> > >
> > > I have prepared a reduced (~680 LoC) version of objcopy with the PE->ELF 
> > > fix added. To support build on non-ELF platforms, I would suggest to add 
> > > this to the GRUB codebase. It can be later extended for other platforms 
> > > if desired.
> > >       
> > I'm not sure what the GRUB maintainers will think, but I'm not very inclined
> > to duplicate stuff that binutils already have.
> >     
>
> So am I.
>
>   

Actually, binutils actually does not have this ("convert relocatable 
object files from format X to ELF") stuff.


> > How about building binutils with --enable-targets=i386-elf ?  Maybe the
> > Cygwin maintainers would even add it as default.  


It is not so easy:

Cygwin's libbfd, ld and objcopy support elf32-i386, gas does not.

But ld refuses to output elf32-i386 if pe-i386 is the input format. This 
restriction is hard-coded into ld because some pe-specific operations 
are hard-coded into bfd backend (This includes the hack which fixes the 
pc-relative relocation in the executable).

Enable elf32-i386 as additional output format for gas does not work. The 
compilation fails, multiple emulations are not supported on i386 platform.

But even building gas as a cross-assembler does not help. Some assembler 
directives, like symbol type specs, are output format specific. Output 
from Cygwin's gcc produces syntax errors.

Therefore, you would need also a gcc build as a cross-compiler.



Not really worth the effort, so I posted the patch for kern/i386/dl.c 
instead.


> > We could also have a
> > configure check that aborts build when -m elf_i386 is not supported (which
> > may also be a problem on pure-x86_64 environment!) and prompt user to
> > rebuild binutils.
> >     
>
>   

Better prompt "sorry", as rebuilding binutils probably won't work OOTB 
in many cases ... :-)

Christian