arch/tile: allow building Linux with transparent huge pages enabled

The change adds some infrastructure for managing tile pmd's more generally,
using pte_pmd() and pmd_pte() methods to translate pmd values to and
from ptes, since on TILEPro a pmd is really just a nested structure
holding a pgd (aka pte).  Several existing pmd methods are moved into
this framework, and a whole raft of additional pmd accessors are defined
that are used by the transparent hugepage framework.

The tile PTE now has a "client2" bit.  The bit is used to indicate a
transparent huge page is in the process of being split into subpages.

This change also fixes a generic bug where the return value of the
generic pmdp_splitting_flush() was incorrect.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 5a74fea182f1..74c0ddaa6fa0 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -109,8 +109,8 @@ pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address,
 
 #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-pmd_t pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
-                           pmd_t *pmdp)
+void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
+                          pmd_t *pmdp)
 {
         pmd_t pmd = pmd_mksplitting(*pmdp);
         VM_BUG_ON(address & ~HPAGE_PMD_MASK);