[coreboot] why is firmware 32 bit as opposed to 64 bit

[ron minnich]

I understand the arguments.

It's worth remembering that coreboot has to date run on 5 different
architectures. 4 of those used paging. The x86 has always been the
outlier. Lack of paging has costs not discussed much. Rmodules would
be a lot simpler if we had paging. We could make the code space
readonly, which we should be doing anyway. We would have less fighting
with the granularity and alignment restrictions of MTRRs. We could
catch NULL pointers in hardware. These are clear benefits. And they
all apply to the ramstage as well as other stages.

As to 64 bit ramstage, I see lots of benefits for my use cases, but I
may be the only one.

In any event, this is all stuff that can be measured, and I propose to
implement and measure it. Then we can see. I'm not convinced that a
few percent either way on code size is a showstopper.

ron