tile: handle super huge pages in virt_to_pte

This tile-specific API had a minor bug, in that if a super huge (>4GB)
page mapped a particular address range, we wouldn't handle it correctly.
As part of fixing that bug, I also cleaned up some of the pud and pmd
accessors to make them more consistent.

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

arch/tile/include/asm/pgtable_64.h

@@ -63,6 +63,15 @@
 /* We have no pud since we are a three-level page table. */
 #include <asm-generic/pgtable-nopud.h>
 
+/*
+ * pmds are the same as pgds and ptes, so converting is a no-op.
+ */
+#define pmd_pte(pmd) (pmd)
+#define pmdp_ptep(pmdp) (pmdp)
+#define pte_pmd(pte) (pte)
+
+#define pud_pte(pud) ((pud).pgd)
+
 static inline int pud_none(pud_t pud)
 {
 	return pud_val(pud) == 0;
@@ -73,6 +82,11 @@ static inline int pud_present(pud_t pud)
 	return pud_val(pud) & _PAGE_PRESENT;
 }
 
+static inline int pud_huge_page(pud_t pud)
+{
+	return pud_val(pud) & _PAGE_HUGE_PAGE;
+}
+
 #define pmd_ERROR(e) \
 	pr_err("%s:%d: bad pmd 0x%016llx.\n", __FILE__, __LINE__, pmd_val(e))
 
@@ -89,6 +103,9 @@ static inline int pud_bad(pud_t pud)
 /* Return the page-table frame number (ptfn) that a pud_t points at. */
 #define pud_ptfn(pud) hv_pte_get_ptfn((pud).pgd)
 
+/* Return the page frame number (pfn) that a pud_t points at. */
+#define pud_pfn(pud) pte_pfn(pud_pte(pud))
+
 /*
  * A given kernel pud_t maps to a kernel pmd_t table at a specific
  * virtual address.  Since kernel pmd_t tables can be aligned at
@@ -152,13 +169,6 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 	return hv_pte(__insn_exch(&ptep->val, 0UL));
 }
 
-/*
- * pmds are the same as pgds and ptes, so converting is a no-op.
- */
-#define pmd_pte(pmd) (pmd)
-#define pmdp_ptep(pmdp) (pmdp)
-#define pte_pmd(pte) (pte)
-
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_TILE_PGTABLE_64_H */