Re: Building GRUB on platforms without ELF support

[Robert Millan]

On Fri, Nov 16, 2007 at 11:58:14PM +0100, Christian Franke wrote:
> Building GRUB modules requires ELF support in gas and ld. For platforms 
> where ELF is not the native format, ld may support ELF output. If not 
> (like on Cywin) some conversion to ELF is necessary.
> 
> In general, GNU objcopy allows conversion between object file formats. 
> Unfortunately, objcopy (and BFD itself) does not include any support for 
> the conversion of relocation formats (even conversion between ELF 
> variants do not work). In particular, when converting PE (a COFF 
> variant) to ELF, objcopy does not abort but silently produces bad 
> PC-relative relocation offsets. In my first Cygwin patch, there is a 
> hack to fix this in the GRUB ELF loader.
> 
> 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.

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

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call, if you are unable to speak?
(as seen on /.)