Re: [ppc patch] grub-mkimage

[Hollis Blanchard]

On Dec 3, 2004, at 6:50 AM, Marco Gerards wrote:

> Hollis Blanchard <address@hidden> writes:
>
> > Use the -n/--note switch to add the CHRP NOTE segment on CHRP 
> > platforms
> > (e.g. briQ and Pegasos). NEVER use this switch on Power Macintosh. I
> > guess that should be documented better in the help text, but 
> > anyways...
>
> Oh, weird.  For me grubof worked on the PegasosII without doing this.

Ah, my mistake then, good to know. The NOTE segment is still needed on 
briQ, RS/6000, and pSeries of course.

> > It may be possible to place module variables into their own section
> > containing nothing else, yet still in a LOAD segment.  Then 
> > grub-mkimage
> > could parse the *section* table (right now it only does segments) and
> > overwrite the contents of this section to inform the runtime of the
> > module location. I'm not convinced it's worth the effort.
>
> Whatever is the most flexible seems the best to me...

I was aiming for simplicity really... What's the simplest possible way 
we can inform grubof of the location of its modules? :)

> AS Hollis said, I'm working on the relocator for PPC at the moment.
> It is quite easy, but PPC_REL24 is a bit more complex.  It is used for
> relative jumps.  That means the module should be loaded close to
> grubof, which IMHO really sucks...

24-bit offsets give you a 16 MiB range, is that really a problem?

> I am now trying to get option 2 to work first (by using black magic to
> get everything loaded at the right address ;)) and when module loading
> works for me I will try to make 3 work.

I agree this makes sense. I'm not sure that option 3 will end up being 
necessary, but option 2 is obviously needed.

> Does someone else think I
> try to do something else, or can someone help a bit somehow?  As you
> might have noticed I really suck at this stuff and doing it just
> because no one else does. ;)

I've never seen relocation code before, but if it's still not working 
when I get back I'd be happy to take a look...

-Hollis