[coreboot] Returning control to v3 from the payload

Marc Karasek Marc.Karasek at Sun.COM
Fri Mar 14 16:37:58 CET 2008

IMO, It would be a good idea to have this functionality.

It is not always possible to return to the state prior to jumping to the 
payload.  This is because you do not have any control over where the 
problem in the load of the "next" image happens.

It might be interesting to have an error code of some type returned so 
that coreboot can take a make a decision on what to do next.  For 
example if it fails because of some hardware item, it should prob not 
try to load an alternate image, but if a crc check of an image fails, 
then an alternate load would be possible.

In doing this for embedded systems, I have never assumed that control 
would be returned with a "known" state and always did some basic reinit 
(SP, etc..) so that I would not crash myself.

Just my 2 cents...

Marc Karasek
Sun Microsystems
mailto:marc.karasek at sun.com

Jordan Crouse wrote:
> Somewhere in the back of my mind, I think I recall it was a design
> goal that we support returning control back to v3 from the payload
> and loading an alternate payload or panicing sanely.
> Is this still a legitimate goal for v3?  If so, how much of the original
> environment needs to be restored before the payload returns control?
> I ask because I'm finishing up the last touches of the libpayload
> BSD rewrite, and this is really the last thing I need to worry about.
> Jordan

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