Re: [git pull] x86 fixes

[Jeremy Fitzhardinge]

Johannes Weiner wrote:
> Hi,
>
> Ingo Molnar <mingo@xxxxxxx> writes:
>
>   
> > Linus,
> >
> > Please pull the latest x86 fixes git tree from:
> >
> >    git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git x86-fixes-for-linus
> >
> > Thanks,
> >
> > 	Ingo
> >
> > ------------------>
> > Jan Kratochvil (1):
> >       x86: fix crash due to missing debugctlmsr on AMD K6-3
> >
> > Jeremy Fitzhardinge (2):
> >       x86: rename PTE_MASK to PTE_PFN_MASK
> >       x86: add PTE_FLAGS_MASK
> >     
>
> Are you serious?  It goes _this_ fast?  The patch came into my mbox at
> 8:00am this morning and you push it to Linus at 4:00pm already?
>
> What about the inconsistency it introduces?  When I look at PAGE_MASK
> for example, it masks out the PAGE offset.  PTE_MASK masks out PTE
> specifca from a value.
>
> Now, I assume PTE_PFN_MASK masks out the PFN.  Oh, wait, it masks the
> protection bits.

PAGE_MASK turns an address into its page address.

PTE_PFN_MASK takes a pte value and returns the pte's pfn portion (which 
is shifted so it's actually a page address).

In both cases, the X_MASK terminology means that X is extracted, not 
excluded.  Which makes sense; if you have a packed bitfield containing 
multiple values, you wouldn't expect X to be the list of things *not* 
extracted.

(I would be happy to have a PAGE_OFFSET_MASK for all the places where 
you want to extract the offset.)

   J
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