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

[Linus Torvalds]

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
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