powerpc/64: Define ILLEGAL_POINTER_VALUE for 64-bit

[Michael Ellerman]

On Tue, 2016-11-15 at 10:59:38 UTC, Michael Ellerman wrote:
> This is used in poison.h to offset poison values so that they don't
> point directly into user space.
> 
> The value we choose sits roughly between user and kernel space, which
> means on their own the poison values don't point anywhere useful. If an
> attacker can cause an access at some offset from the poison value then
> we may still be in trouble, but by putting the poison values between
> user and kernel space we maximise the required size of that offset.
> 
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>

Applied to powerpc next.

https://git.kernel.org/powerpc/c/f6853eb561fb9bfd56dfe0009f0ea2

cheers