freebios2 mod to reset code.

Stefan Reinauer stepan at suse.de
Wed Jul 23 10:53:00 CEST 2003


* ron minnich <rminnich at lanl.gov> [030723 16:58]:
> > > make reset a rel jump to 0xfffffff0 - (sizeof entry16). Then put entry 16
> > > right before 0xfffffff0. Entry16 code turns on 32-bit mode and then jumps
> > > to the real start of the linuxbios image -- which can now be anywhere in
> > > the flash image. I could use this now, as could others.
 
> sadly, it appears that 0xffe0000 is not enabled at hardware startup. 

> One option is to grow this idea a bit: have the 32-bit mode enable right 
> below 0xfffffff0, but include in that a flash enable. Then it would work. 
 
If a flash enable can always happen that early, this is definitely a
good idea, as we want to know our code as soon as possible.

On the K8 this might mean that this early code has to contain all of:

* check if BSP
* coherent ht init
* non coherent ht enumeration
* enable flash

before actually jumping anywhere down. Don't know if that would all fit.

> By far the simplest thing to do is make it possible to move c_payload 
> around, say to 0xfffe0000

if this means that we can easily make linuxbios fallback and normal
share the same payload, it would be my fav.

Stefan






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