Re: GRUB2 Build on Mac OS X

[Andrei Warkentin]

On Dec 8, 2005, at 4:01 PM, address@hidden wrote:

> The Mac OS X GCC compiler will not build GRUB2, due static linking  
> at address 0x2000; this error can be confirmed during the configure  
> process. If I could build GRUB2 using the Mac OS X GCC, I would be  
> able to build GRUB2 images from Mac OS X.

The OS X ld is not the GNU linker - so sure it can't link at 0x2000,  
it doesn't know what -T means. You would probably use some  
permutation of the -segaddr option. Moreover, OS X uses the Mach-O  
binary format, not ELF...

> The binary I attempted the build using the cross compiler tool  
> chain powerpc-elf, would have executed on PowerPC Linux, but I  
> would not build due to the nested function support being disabled  
> in the Apple GCC

I don't think I understand - you can build a bootstrap GCC targetted  
at powerpc-linux, from the sources obtained via official GNU ftp.  
There would not be any restrictions there... This would allow you to  
build powerpc-elf binaries needed by OF.

> Since the GRUB2 tools built using a Linux GCC compiler will suffice  
> at the moment, I can see why the team is not overly concerned with  
> this issue. If GRUB2 is going to be portable(Mac OS X), then some  
> changes will be needed to accomplish this goal.

I think it would be an interesting idea to allow the use of different  
toolsets to produce the boot-time files and the system utilities.  
This way, the boot-time stuff can be build as powerpc-elf, while the  
OS X system utilities can be built as Mach-O (well, not 'can' -  
should, there is no other way here).

> If stack execution support is disabled in future releases of other  
> operating systems, it will become an issue of nested functions  
> implemented with stack execution, and less of an Apple GCC compiler  
> issue.
>
> I do agree that more arguments will be needed on function calls if  
> nested functions are not going to be used, if the list is willing  
> to accept patches to address this issue.
>
> As far as the GRUB2 tools, binaries executed on the PowerPC  
> platform only need to be pure ELF. I am not sure if creating Mach-O  
> boot binaries will yield any benefits for bringing up a kernel. If  
> GRUB2 is to be used on the Mac OS X operating system, the tools  
> need to be Mach-O based.
>
> Andre
>
> > -----Original Message-----
> > From: Andrei Warkentin [mailto:address@hidden
> > Sent: Thursday, December 8, 2005 08:10 PM
> > To: 'The development of GRUB 2'
> > Subject: Re: GRUB2 Build on Mac OS X
> >
> > I understand (still had my mind on GRUB 1 :)) - then looks like two
> > GCC installations will be
> > required to construct GRUB2 on OS X - one to generate OS X-hosted
> > GRUB utilities (which will
> > be Mach-O files), and one to generate ELF files  that will be used in
> > the booting process.
> >
> > On Dec 8, 2005, at 2:00 PM, Marco Gerards wrote:
> >
> > > Andrei Warkentin <address@hidden> writes:
> > >
> > > Hi Andrei,
> > >
> > > > There is another issue with GRUB2 on OS X which I am not sure has
> > > > been brought up yet.
> > > > Right now, AFAIK (but I haven't tested it), GRUB2 (the part that  
> > > > runs
> > > > from OpenFrimware) can be built
> > > > with a bootstrap powerpc-elf-targetted GCC hosted on OS X. However,
> > > > the local GRUB2 binary (one that can run
> > > > from OS X and perform installation and some such) needs to be
> > > > compiled with the OS X compiler. Why? OS X doesn't use ELF -
> > > > it uses Mach-O. If you want to be able to build GRUB2 in OS X with
> > > > purely the OS X GCC, then the build procedure must take into  
> > > > account
> > > > the Mach-O
> > > > output format. AFAIK, new OpenFirmware versions (3.x) can boot  
> > > > Mach-O
> > > > binaries but I haven't had a chance to experiment with this yet.
> > >
> > > You mean the utilities like grub-setup, grub-mkimage, grub-emu, etc?
> > > They should be able to run on macos, right?  Of perhaps I am missing
> > > your point.
> > >
> > > If those utilities can be build in a better way so nothing breaks  
> > > and
> > > it will work on macos, I am quite interested in hearing how to solve
> > > that.
> > >
> > > Mach-O binaries for booting is a different subject.  We rely on ELF
> > > files, grub-mkimage even creates ELF files and uses ELF load
> > > segments.  Without it GRUB just won't work, unless grub-mkimage is
> > > changed intensively.  So it seems easier just to use ELFs in any  
> > > case.
> > >
> > > --
> > > Marco
> > >
> > >
> > >
> > > _______________________________________________
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> > > address@hidden
> > > http://lists.gnu.org/mailman/listinfo/grub-devel
> >
> >
> >
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