1 files changed, 6 insertions, 0 deletions

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index c1a36dd1e598..a51a97ade636 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -500,6 +500,12 @@ static inline struct page *pgd_page(pgd_t pgd)
 {
         return pfn_to_page(pgd_val(pgd) >> PAGE_SHIFT);
 }
+
+/* to find an entry in a page-table-directory. */
+static inline unsigned pud_index(unsigned long address)
+{
+        return (address >> PUD_SHIFT) & (PTRS_PER_PUD - 1);
+}
 #endif  /* PAGETABLE_LEVELS > 3 */
 
 #endif  /* __ASSEMBLY__ */