Re: [patch 1/6] mm: Allow architectures to define additional protection bits

Hugh Dickins
2008-07-08T13:00:12Z

On Tue, 8 Jul 2008, Benjamin Herrenschmidt wrote:
> On Tue, 2008-07-08 at 08:24 +1000, Benjamin Herrenschmidt wrote:
> > > There is a little inconsistency, that arch_calc_vm_prot_bits
> > > and arch_vm_get_page_prot just handle the exceptional flag (SAO),
> > > whereas arch_validate_prot handles all of them; but I don't feel
> > > so strongly about that to suggest resubmission.
> > >
> > > And regarding VM_SAO added to include/linux/mm.h in 3/6: although
> > > it's odd to be weaving back and forth between arch-specific and
> > > common, it's already the case that mman definitions and pgtable
> > > definitions are arch-specific but mm.h common: I'm much happier
> > > to have VM_SAO defined once there as Dave has it, than get into
> > > arch-specific vm_flags.
> > >
> > > Is someone going to be asking for PROT_WC shortly?
> >
> > I'll definitely come with PROT_ENDIAN soon :-) (ie, some powerpc
> > processors can have a per-page endian flag that when set causes all
> > load/store instructions on this are to be byte-flipped, support for
> > this
> > feature has been requested for some time, and now I have the
> > infrastructure to do it).
>
> BTW. Do we have your ack ?

To PROT_SAO? Okay,
Acked-by: Hugh Dickins <hugh@veritas.com>

>
> Andrew, what tree should this go via ? I have further powerpc patches
> depending on this one... so on one hand I'd be happy to take it, but
> on the other hand, it's more likely to clash with other things...
>
> Maybe I should check how it applies on top of linux-next.
>
> Ben.