Re: patch for PPC Old World Macintosh

[Hollis Blanchard]

On Aug 30, 2004, at 11:17 AM, Marco Gerards wrote:

> Hollis Blanchard <address@hidden> writes:
>
> Did you had the chance to test your code on a new world mac?  If not,
> I will do so.

I haven't, no.

> I see that you are claiming all memory available.  This is really nice
> but we need to consider two things when doing this.
>
> 1) It all needs to be freed.  Currently I did not free the claimed
>    memory (shame on me).

Could this can be done by walking the grub_mm_regions allocated via 
grub_mm_init_region() and freeing them one by one? I guess we only want 
to release the memory just before launching a kernel, so even if the 
memory is still "in use" by GRUB code it should be safe to give it up.

> 2) The linux loader claims some memory and want it to be mapped on the
>    address on which the kernel was linked.  If all memory is claimed
>    already this will not work.

Hmm. I think the i386 loader doesn't worry about such things, but 
rather loads the kernel in a fixed region?

One easy possibility is this: don't reserve all memory at all. Instead 
reserve a fixed amount that we know we need, and if a kernel wants to 
be loaded there then fail. Since the kernel load address doesn't change 
often we can probably find a spot that's both big enough for GRUB and 
doesn't conflict.

What is the advantage of giving more memory to grub_mm_init_region() 
anyways? If it's not very important (e.g. a small performance 
improvement when loading a file from a filesystem) then I think we can 
agree that avoiding conflict with the kernel is more important...

-Hollis