Total 32 keys are available on power7 and above. However
pkey 0,1 are reserved. So effectively we have 30 pkeys.
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.
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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