[SeaBIOS] [RFC 2/3] Transitions to and from 64 bits

[Kevin O'Connor]

On Mon, Sep 21, 2015 at 12:03:29PM -0400, Kevin O'Connor wrote:
> According to my Intel docs, PAE supports the same 52bit physical
> address range that x86_64 supports.

Thinking about this further, I could see changing SeaBIOS' 32bit code
to always use PAE mode (when available).  Doing so would enable
support for PCI devices mapped above 64bit (there is already a USB
exception in pciinit.c because of this).  It would mean implementing
ioremap and teaching malloc and the drivers to use it, but that seems
doable.  A simple PAE ioremap implementation could use 2MB pages
exclusively which would reduce complexity.

-Kevin