Re: [PATCH UPDATED] x86: set PAE PHYSICAL_MASK_SHIFT to 44 bits.

[Jeremy Fitzhardinge]

Ingo Molnar wrote:
> > When a 64-bit x86 processor runs in 32-bit PAE mode, a pte can 
> > potentially have the same number of physical address bits as the 
> > 64-bit host ("Enhanced Legacy PAE Paging").  This means, in theory, we 
> > could have up to 52 bits of physical address in a pte.
> >
> > The 32-bit kernel uses a 32-bit unsigned long to represent a pfn. This 
> > means that it can only represent physical addresses up to 32+12=44 
> > bits wide.  Rather than widening pfns everywhere, just set 2^44 as the 
> > Linux x86_32-PAE architectural limit for physical address size.
> >     
>
> applied to tip/x86/cleanups - thanks Jeremy. No urgency for v2.6.26, 
> right?

Not urgent, but it would be nice to have.

   J

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