powerpc: Only do ERAT invalidate on radix context switch on P9 DD1

[Michael Ellerman]

On Sun, 2017-06-25 at 20:08:46 UTC, Benjamin Herrenschmidt wrote:
> From: Michael Neuling <mikey at neuling.org>
> 
> On P9 (Nimbus) DD2 and later, in radix mode, the move to the PID
> register will implicitly invalidate the user space ERAT entries
> and leave the kernel ones alone. Thus the only thing needed is
> an isync() to synchronize this with subsequent uaccess's 
> 
> Signed-off-by: Michael Neuling <mikey at neuling.org>
> Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/74e27c6af56fe6898c3c8c45159574

cheers