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, 8 insertions, 18 deletions

diff --git a/arch/tile/include/asm/pgtable_32.h b/arch/tile/include/asm/pgtable_32.h
index 9f98529761fd..27e20f6844a8 100644
--- a/arch/tile/include/asm/pgtable_32.h
+++ b/arch/tile/include/asm/pgtable_32.h
@@ -111,24 +111,14 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 	return pte;
 }
 
-static inline void __set_pmd(pmd_t *pmdp, pmd_t pmdval)
-{
-	set_pte(&pmdp->pud.pgd, pmdval.pud.pgd);
-}
-
-/* Create a pmd from a PTFN. */
-static inline pmd_t ptfn_pmd(unsigned long ptfn, pgprot_t prot)
-{
-	return (pmd_t){ { hv_pte_set_ptfn(prot, ptfn) } };
-}
-
-/* Return the page-table frame number (ptfn) that a pmd_t points at. */
-#define pmd_ptfn(pmd) hv_pte_get_ptfn((pmd).pud.pgd)
-
-static inline void pmd_clear(pmd_t *pmdp)
-{
-	__pte_clear(&pmdp->pud.pgd);
-}
+/*
+ * pmds are wrappers around pgds, which are the same as ptes.
+ * It's often convenient to "cast" back and forth and use the pte methods,
+ * which are the methods supplied by the hypervisor.
+ */
+#define pmd_pte(pmd) ((pmd).pud.pgd)
+#define pmdp_ptep(pmdp) (&(pmdp)->pud.pgd)
+#define pte_pmd(pte) ((pmd_t){ { (pte) } })
 
 #endif /* __ASSEMBLY__ */