x86: unify pte_index

Impact: cleanup

Unify and demacro pte_index.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 49b5cff78c28..10a8c2e51789 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -498,6 +498,17 @@ static inline unsigned pmd_index(unsigned long address)
  */
 #define mk_pte(page, pgprot)   pfn_pte(page_to_pfn(page), (pgprot))
 
+/*
+ * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
+ *
+ * this function returns the index of the entry in the pte page which would
+ * control the given virtual address
+ */
+static inline unsigned pte_index(unsigned long address)
+{
+        return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
+}
+
 #if PAGETABLE_LEVELS > 2
 static inline int pud_present(pud_t pud)
 {