parisc: Fix serial console for machines with serial port on superio chip

Fix the serial console on machines where the serial port is located on
the SuperIO chip.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Peter Hurley <peter@hurleysoftware.com>
mm: migrate: Close race between migration completion and mprotect

A migration entry is marked as write if pte_write was true at the time the
entry was created. The VMA protections are not double checked when migration
entries are being removed as mprotect marks write-migration-entries as
read. It means that potentially we take a spurious fault to mark PTEs write
again but it's straight-forward. However, there is a race between write
migrations being marked read and migrations finishing. This potentially
allows a PTE to be write that should have been read. Close this race by
double checking the VMA permissions using maybe_mkwrite when migration
completes.

[torvalds@linux-foundation.org: use maybe_mkwrite]
Cc: stable@vger.kernel.org
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: numa: Do not mark PTEs pte_numa when splitting huge pages

This patch reverts 1ba6e0b50b ("mm: numa: split_huge_page: transfer the
NUMA type from the pmd to the pte"). If a huge page is being split due
a protection change and the tail will be in a PROT_NONE vma then NUMA
hinting PTEs are temporarily created in the protected VMA.

 VM_RW|VM_PROTNONE
|-----------------|
      ^
      split here

In the specific case above, it should get fixed up by change_pte_range()
but there is a window of opportunity for weirdness to happen. Similarly,
if a huge page is shrunk and split during a protection update but before
pmd_numa is cleared then a pte_numa can be left behind.

Instead of adding complexity trying to deal with the case, this patch
will not mark PTEs NUMA when splitting a huge page. NUMA hinting faults
will not be triggered which is marginal in comparison to the complexity
in dealing with the corner cases during THP split.

Cc: stable@vger.kernel.org
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'numa-migration-fixes' (fixes from Mel Gorman)

Merge NUMA balancing related fixlets from Mel Gorman:
 "There were a few minor changes so am resending just the two patches
  that are mostly likely to affect the bug Dave and Sasha saw and marked
  them for stable.

  I'm less confident it will address Sasha's problem because while I
  have not kept up to date, I believe he's also seeing memory corruption
  issues in next from an unknown source.  Still, it would be nice to see
  how they affect trinity testing.

  I'll send the MPOL_MF_LAZY patch separately because it's not urgent"

* emailed patches from Mel Gorman <mgorman@suse.de>:
  mm: numa: Do not mark PTEs pte_numa when splitting huge pages
  mm: migrate: Close race between migration completion and mprotect
Merge branch 'parisc-3.17-8' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fix from Helge Deller:
 "One late but trivial patch to fix the serial console on parisc
  machines which got broken during the 3.17 release cycle"

* 'parisc-3.17-8' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix serial console for machines with serial port on superio chip