Re: [patch 0/4] x86: PAT followup - Incremental changes and bug fixes

Ingo Molnar
2008-01-17T22:47:58Z

* Andreas Herrmann3 <andreas.herrmann3@amd.com> wrote:

> > I'll check this asap
>
> So, now that I've avoided this tiny NULL-pointer-dereference, the
> system boots fine as well with your (slightly modified) patch. See
> dmesg attached.

for now i applied your ioremap_uncached() patch and removed my patch.

my patch might work if the MTRR marks that area UC. Does it on your
system?

if the MTRRs (as set up by the BIOS) keep it at WB, then the ACPI
ioremap() is already unsafe: the mmio area that happens to be there
might be prefetched by the CPU.

Ingo