Re: Question regarding x86_64 __PHYSICAL_MASK_SHIFT

[Andi Kleen]

On Tuesday 04 October 2005 21:19, Tejun Heo wrote:

>   Hmmm.. but, currently
>
> * PHYSICAL_PAGE_MASK == (~(PAGE_SIZE-1)&(__PHYSICAL_MASK << PAGE_SHIFT)
> 	== (0xffffffff_fffff000 & (0x00003fff_ffffffff << 12)
>   	== 0x03ffffff_fffff000
>   while it actually should be 0x00003fff_fffff000

Right. Fixed now

> * PTE_FILE_MAX_BITS == __PHYSICAL_MASK_SHIFT == 46, but only 40bits are
> available in page table entries.

The non linear mapping format is independent from the MMU, the number
is pretty much arbitary, but it is consistent to make it the same as
other ptes for easier sanity checking.

-Andi
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