Re: [PATCH 1/6] bootwrapper: arch/powerpc/boot code reorg

["Mark A. Greer" <mgreer@mvista.com>]

On Wed, Aug 02, 2006 at 04:15:05PM +1000, Paul Mackerras wrote:
> I wrote:
> 
> > The ops structure seems like a reasonable concept, but I question
> > whether we need to have platform_ops separate from fw_ops, since the
> > firmware is essentially part of the implementation of the platform.
> > Also I don't see why we need to do a double indirection to get to each
> > ops function.
> 
> Thinking about this a bit more, why do we need the indirect function
> calls at all?  Do we ever want to be able to choose (e.g.) one of
> several possible console implementations at runtime?  Don't we know at
> compile time which one we will be using, and thus can't we use the
> linker to make the necessary linkages?

The hooking up was done at runtime for relocation reasons.
The got relocation code in crt0.S doesn't handle a function address
statically assigned to a structure member.  I don't think its safe
to assume that 0x4000 is safe on all platforms, either, so relocation is
probably a fact of life.  We could hack crt0.S instead, if you prefer?

Mark