Re: [PATCH RFC] x86: check for and defend against BIOS memory corruption

H. Peter Anvin
2008-08-29T17:07:45Z

Hugh Dickins wrote:
>
> hpa introduced the 64k idea, and we've all been repeating it;
> but I've not heard the reasoning behind it. Is it a fundamental
> addressing limitation within the BIOS memory model? Or a case
> that Windows treats the bottom 64k as scratch, so BIOS testers
> won't notice if they corrupt it?
>

I should point out that I have seen one particular bug quite a few times
poking around with boot loaders: the BIOS accesses memory at an
otherwise valid address, but with the segment base set to either zero or
0x400 instead of whatever it should have been.

-hpa