Re: [coreboot] [PATCH] Istanbul support

[Arne Georg Gleditsch]

Stefan Reinauer  writes:
> Nice... !
>
> I've been wondering before... why this odd approach with read8x and
> gs:... instead of just doing normal read8/16/32 ?

Primarily to enable mapping in 64-bit space, I suppose.  I guess we
could map AMD fam10 mmio config space into 32 bit-space as well, the
main reason not to is that it consumes quite a lot of space.
> Where's %gs set up for romcc_io usage?

src/cpu/amd/model_10xxx/init_cpus.c, set_pci_mmio_conf_reg.  I added
explicit per-invocation assignment for post-car since the base is lost
whenever %gs is changed.  (Which happened once on transition to post-car
and which I assume can happen arbitrarily when we're executing option
roms).