Re: [PATCH 03/25] powerpc: track allocation status of all pkeys

Ram Pai [off-list ref] writes:

Total 32 keys are available on power7 and above. However
pkey 0,1 are reserved. So effectively we  have  30 pkeys.

When you say reserved, reserved by whom? Is that part of ISA or PAPR ?
Also do you expect that to change. If not why all these indirection?
Can we have the mask as a #define for 4K and 64K page size
config?

On 4K kernels, we do not  have  5  bits  in  the  PTE to
represent  all the keys; we only have 3bits.Two of those
keys are reserved; pkey 0 and pkey 1. So effectively  we
have 6 pkeys.

This patch keeps track of reserved keys, allocated  keys
and keys that are currently free.

Also it  adds  skeletal  functions  and macros, that the
architecture-independent code expects to be available.

-aneesh