Re: Linux 2.6.26-rc1 - pgtable_32.c:178 pmd_bad

From: Ingo Molnar
Date: Tue May 06 2008 - 11:16:01 EST



* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Tue, 6 May 2008, Ingo Molnar wrote:
> >
> > hm, the main objection was about whether to turn PAGE_SIZE from
> > unsigned into signed though - and that we didnt do.
>
> No it wasn't.
>
> The main objection was that you SHOULD NOT USE PAGE_SIZE_MASK AT ALL!
>
> You should have used a pagetable-specific macro, becuse PAGE_MASK is
> simply fundamentally WRONG, and has absolutely nothing to do with the
> PFN bits, whether sign-extended or not!
>
> The fact is, the page frane number bits are *not* ~PAGE_MASK or
> anything like that. They share only the low bits - not the high bits.

yeah, indeed, sorry about that. Will sort this type mixing out today.

Ingo
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