Re: [RFC v5 01/38] powerpc: Free up four 64K PTE bits in 4K backed HPTE pages

From: Balbir Singh
Date: Fri Jul 07 2017 - 03:27:19 EST

On Wed, 2017-07-05 at 14:21 -0700, Ram Pai wrote:
> Rearrange 64K PTE bits to free up bits 3, 4, 5 and 6,
> in the 4K backed HPTE pages.These bits continue to be used
> for 64K backed HPTE pages in this patch, but will be freed
> up in the next patch. The bit numbers are big-endian as
> defined in the ISA3.0
> The patch does the following change to the 4k htpe backed
> 64K PTE's format.

The diagrams make the patch much easier to understand, thanks!


> NOTE:even though bits 3, 4, 5, 6, 7 are not used when
> the 64K PTE is backed by 4k HPTE, they continue to be
> used if the PTE gets backed by 64k HPTE. The next
> patch will decouple that aswell, and truely release the
> bits.


Balbir Singh.