powerpc fixes for 4.15 #2

A small batch of fixes, about 50% tagged for stable and the rest for recently
merged code.

There's one more fix for the >128T handling on hash. Once a process had
requested a single mmap above 128T we would then always search above 128T. The
correct behaviour is to consider the hint address in isolation for each mmap
request.

Then a couple of fixes for the IMC PMU, a missing EXPORT_SYMBOL in VAS, a fix
for STRICT_KERNEL_RWX on 32-bit, and a fix to correctly identify P9 DD2.1 but in
code that is currently not used by default.

Thanks to:
  Aneesh Kumar K.V, Christophe Leroy, Madhavan Srinivasan, Sukadev Bhattiprolu.
powerpc/64s: Fix Power9 DD2.1 logic in DT CPU features

I got the logic wrong in the DT CPU features code when I added the
Power9 DD2.1 feature. We should be setting the bit if we detect a
DD2.1, not clearing it if we detect a DD2.0.

This code isn't actually exercised at the moment so nothing is
actually broken.

Fixes: 3ffa9d9e2a7c ("powerpc/64s: Fix Power9 DD2.0 workarounds by adding DD2.1 feature")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
1 file changed