[coreboot] Porting to Asus M4A785-M

Myles Watson mylesgw at gmail.com
Thu Aug 26 22:58:48 CEST 2010

> > It doesn't seem good that the Multiboot table gets written before the
> > UMA and high table areas are added.  I would think that's why they
> > don't show up.
> >
> Yes, that was it, thanks for the advice.
I'm glad it helped.

> I checked with coreinfo, and multiboot table did not have a clue about
> high tables area or UMA. Furthermore, it looked very much like the e820
> table Linux was receiving.
> Reading the source of multiboot table writer in Coreboot, it says in the
> comments that adding reserved memory areas is not yet implemented.
> Then I set out to implement that. I figured that the easiest way to get
> the memory areas is to copy them from coreboot table. The problem in
> this approach was that multiboot table is written to memory before
> coreboot table is constructed, so there is nothing to copy.
> To get around this, I changed the writing order so that coreboot table
> is written to memory first, and then multiboot table is copied from
> that. I hope this does not break any specification.
> In any case, this resulted in a working BIOS e820 memory map for Linux,
> which can now be booted from Grub2.
> I hope I could soon contribute a patch for this mainboard to the
> Coreboot project, but first I have to clean the code I have mangled back
> and forth.

I'd suggest a separate patch for the multiboot tables fix.  I'm looking
forward to seeing how you fixed it.


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