Re: [git pull] x86 fixes

Johannes Weiner
2008-07-22T15:23:41Z

Hi,

Jeremy Fitzhardinge <jeremy@goop.org> writes:

> Johannes Weiner wrote:
>> Hi,
>>
>> Ingo Molnar <mingo@elte.hu> 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).

Okay, now it makes sense.

I just always thought of PAGE_MASK as `mask out sub-page granularity'.

> 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.

Agreed.

Hannes