_PAGE_PRESENT and _PAGE_ACCESSED

[Benjamin Herrenschmidt]

On Tue, 2016-07-26 at 19:52 +0200, LEROY Christophe wrote:
> In ppc8xx tlbmiss handler, we consider a page valid if both  
> _PAGE_PRESENT and _PAGE_ACCESSED are set.
> Is there any chance to have _PAGE_ACCESSED set and not _PAGE_PRESENT ?
> Otherwise we could simplify the handler by considering the page valid  
> only when _PAGE_ACCESSED is set

When _PAGE_PRESENT is not set, the PTE becomes a swap PTE and a pile
of the other bits can be repurposed, you may want to verify if
_PAGE_ACCESSED is one of them.

Cheers,
Ben.