tree 32c5263ce80a6d96ec35a66edac9ec6e97774944
parent 6d888d1ab0000dff8ea2901bcdf5d213f2a54e8b
author Anton Blanchard <anton@samba.org> 1384746928 +1100
committer Benjamin Herrenschmidt <benh@kernel.crashing.org> 1384990421 +1100

powerpc: ppc64 address space capped at 32TB, mmap randomisation disabled

Commit fba2369e6ceb (mm: use vm_unmapped_area() on powerpc architecture)
has a bug in slice_scan_available() where we compare an unsigned long
(high_slices) against a shifted int. As a result, comparisons against
the top 32 bits of high_slices (representing the top 32TB) always
returns 0 and the top of our mmap region is clamped at 32TB

This also breaks mmap randomisation since the randomised address is
always up near the top of the address space and it gets clamped down
to 32TB.

Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>