[PATCH 12/12] [POWERPC] 85xx: Add support for relocatble kernel (and booting at non-zero)

Kumar Gala galak at kernel.crashing.org
Wed Apr 16 10:50:55 EST 2008


On Apr 15, 2008, at 7:03 PM, Paul Mackerras wrote:
> Kumar Gala writes:
>
>>> What happens if CONFIG_KERNEL_START != CONFIG_PAGE_OFFSET and the
>>> kernel is loaded at some address != CONFIG_PHYSICAL_START?
>>
>> Assuming its not a CONFIG_RELOCATABLE kernel than bad things.  Is
>> there some concern you have here?
>
> No, I meant if it is a CONFIG_RELOCATABLE kernel.

if CONFIG_RELOCATABLE is set, than PHYSICAL_START has no meaning  
(beyond being what we set paddr to for the PHDR).

Its ok if KERNEL_START != PAGE_OFFSET.  The key is that the physical  
address the kernel is loaded at meet the alignment requirements.   
(currently 256M, will relax in the future once we get a form of this  
in the tree).

> BTW, the various bits of discussion we've about this stuff would make
> good material for the patch description.

Agreed was thinking the same thing.  Suggestions on useful bits to add  
are welcome.

- k



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