ELF boot and Multiboot

[SONE Takeshi]

On Wed, Jun 11, 2003 at 11:20:23PM -0600, Eric W. Biederman wrote:
> > In the source of mkelfImage, linux-i386/convert_params.c,
> > there is some code to retrieve information like memory map
> > from Multiboot information structure.
> > However, ELF images created by mkelfImage does not have
> > Multiboot header, according to 'mbchk' of GRUB boot loader.
> > In what situation is this code supposed to run (and tested)?
> 
> The partial multiboot support in etherboot, is where it was used.

Thanks for the information.

> > If one added a (trivial) Multiboot header in the head.S,
> > the resulting kernel could be loaded from GRUB, while it could also
> > be loaded by ELF boot of LinuxBIOS and Etherboot?
> 
> It probably could.  And I would not have a problem with something
> like that in theory.  The multiboot spec is quite poorly done,
> so I am not a major fan.  I think I would prefer to just add a
> dummy elf segment at the start of the file with that information
> in it.  From mkelfImage 2.5 that would probably be the easiest thing
> to do.

I couldn't find an easy way to do it.
What PT_* type would that segment have?

> I would almost rather fix GRUB to use something sensible and portable
> like ELF notes.  The multiboot data structure is  a disaster in terms
> of both future expansion, and of expansion by multiple groups.

I considered to add ELFboot support to GRUB, but adding Multiboot
header to ELF kernel looked much easier.

--
Takeshi