diff --git a/arch/ia64/include/asm/pgtable.h b/arch/ia64/include/asm/pgtable.h
index 165827774bea..b1e7468eb65a 100644
--- a/arch/ia64/include/asm/pgtable.h
+++ b/arch/ia64/include/asm/pgtable.h
@@ -544,7 +544,6 @@ extern struct page *zero_page_memmap_ptr;
 
 #  ifdef CONFIG_VIRTUAL_MEM_MAP
   /* arch mem_map init routine is needed due to holes in a virtual mem_map */
-#   define __HAVE_ARCH_MEMMAP_INIT
     extern void memmap_init (unsigned long size, int nid, unsigned long zone,
 			     unsigned long start_pfn);
 #  endif /* CONFIG_VIRTUAL_MEM_MAP */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bdb7eb25acf8..94725aea672f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5631,10 +5631,11 @@ static void __meminit zone_init_free_lists(struct zone *zone)
 	}
 }
 
-#ifndef __HAVE_ARCH_MEMMAP_INIT
-#define memmap_init(size, nid, zone, start_pfn) \
-	memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY, NULL)
-#endif
+void __meminit __weak memmap_init(unsigned long size, int nid,
+				  unsigned long zone, unsigned long start_pfn)
+{
+	memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL);
+}
 
 static int zone_batchsize(struct zone *zone)
 {