Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE

Linus Torvalds
2004-05-25T22:01:55Z

On Tue, 25 May 2004, Andrea Arcangeli wrote:
>
> I expected the pal code to re-read the pte if the control bits asked for
> page fault, like it must happen if the control bits are set to
> non-present.

That may or may not be true. I _think_ it wasn't true.

> This latter this must be true or linux wouldn't run at all
> on alpha.

A "not-present" fault is a totally different fault from a "protection
fault". Only the not-present fault ends up walking the page tables, if I
remember correctly.

The PAL-code sources are out there somewhere, so I guess this should be
easy to check if I wasn't so lazy.

Linus