diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 8ac8e9fd5614fa10237dc58fa6620d52cff8e5e3..8e950cdff1a0e76718777614da3fe4fe15df4c73 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -1017,8 +1017,8 @@ int __devinit smp_prepare_cpu(int cpu)
 	tsc_sync_disabled = 1;
 
 	/* init low mem mapping */
-	memcpy(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
-			sizeof(swapper_pg_dir[0]) * KERNEL_PGD_PTRS);
+	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
+			KERNEL_PGD_PTRS);
 	flush_tlb_all();
 	schedule_work(&task);
 	wait_for_completion(&done);
diff --git a/arch/i386/mm/pgtable.c b/arch/i386/mm/pgtable.c
index bd2f7afc7a2a5d6726b14a35bdf48492bf4730a1..dcdce2c6c53239ad1ba747319ea6aecefa6d7a1a 100644
--- a/arch/i386/mm/pgtable.c
+++ b/arch/i386/mm/pgtable.c
@@ -207,19 +207,19 @@ void pgd_ctor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 {
 	unsigned long flags;
 
-	if (PTRS_PER_PMD == 1)
+	if (PTRS_PER_PMD == 1) {
+		memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
 		spin_lock_irqsave(&pgd_lock, flags);
+	}
 
-	memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD,
+	clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
 			swapper_pg_dir + USER_PTRS_PER_PGD,
-			(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
-
+			KERNEL_PGD_PTRS);
 	if (PTRS_PER_PMD > 1)
 		return;
 
 	pgd_list_add(pgd);
 	spin_unlock_irqrestore(&pgd_lock, flags);
-	memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
 }
 
 /* never called when PTRS_PER_PMD > 1 */
diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index d74185aee15b798d7e38ddea5cf3b3d5535ccec8..47bc1ffa3d4cfb42321cec3bf25d9da23ccc8486 100644
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -277,6 +277,21 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
 	clear_bit(_PAGE_BIT_RW, &ptep->pte_low);
 }
 
+/*
+ * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
+ *
+ *  dst - pointer to pgd range anwhere on a pgd page
+ *  src - ""
+ *  count - the number of pgds to copy.
+ *
+ * dst and src can be on the same page, but the range must not overlap,
+ * and must not cross a page boundary.
+ */
+static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
+{
+       memcpy(dst, src, count * sizeof(pgd_t));
+}
+
 /*
  * Macro to mark a page protection value as "uncacheable".  On processors which do not support
  * it, this is a no-op.