freebios2 mod to reset code.

[Steve Gehlbach]

ron minnich wrote:

> 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.
> 

I suggested this last year, with the comment that this is a more 
traditional way that embedded systems start up.  Your objections at the 
time were that it would cause trouble with some motherboards, but I 
don't remember the specifics.  I was wanting to do this since it is 
clear that we will be getting 2 Mbyte LPC soon and be able to boot 
Linux easily out of flash (as I think you have already done).

One caveat I discovered, I could never get Linux to boot with a gdt 
located higher than 1M.  So even if you put a linux compatible gdt high, 
it has to be moved to ram < 1M or linux hangs on boot.  Never figured 
out why (true for 2.4 anyway).

Also, on the dynamic/static trees, one thing to consider in the mix is 
the serial ATA.  I think it is an external chip now but will be subsumed 
into the bridge chips at some point.  Not sure how a chip function 
moving around like this affects the software design.

-Steve