[PATCH V3 09/10] powerpc/mm: Lower the max real address to 53 bits

[Paul Mackerras]

On Tue, Mar 21, 2017 at 10:59:59PM +0530, Aneesh Kumar K.V wrote:
> Max value supported by hardware is 51 bits address. Radix page table define
> a slot of 57 bits for future expansion. We restrict the value supported in
> linux kernel 53 bits, so that we can use the bits between 57-53 for storing
> hash linux page table bits. This is done in the next patch.
> 
> This will free up the software page table bits to be used for features
> that are needed for both hash and radix. The current hash linux page table
> format doesn't have any free software bits. Moving hash linux page table
> specific bits to top of RPN field free up the software bits for other purpose.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>

Reviewed-by: Paul Mackerras <paulus at ozlabs.org>