diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
index 05aa2d4..d5ea8a6 100644
--- a/drivers/firmware/memmap.c
+++ b/drivers/firmware/memmap.c
@@ -31,8 +31,12 @@
  * information is necessary as for the resource tree.
  */
 struct firmware_map_entry {
-	resource_size_t		start;	/* start of the memory range */
-	resource_size_t		end;	/* end of the memory range (incl.) */
+	/*
+	 * start and end must be u64 rather than resource_size_t, because e820
+	 * resources can lie at addresses above 4G.
+	 */
+	u64			start;	/* start of the memory range */
+	u64			end;	/* end of the memory range (incl.) */
 	const char		*type;	/* type of the memory range */
 	struct list_head	list;	/* entry for the linked list */
 	struct kobject		kobj;   /* kobject for each entry */
@@ -101,7 +105,7 @@
  * Common implementation of firmware_map_add() and firmware_map_add_early()
  * which expects a pre-allocated struct firmware_map_entry.
  **/
-static int firmware_map_add_entry(resource_size_t start, resource_size_t end,
+static int firmware_map_add_entry(u64 start, u64 end,
 				  const char *type,
 				  struct firmware_map_entry *entry)
 {
@@ -132,8 +136,7 @@
  *
  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
  **/
-int firmware_map_add(resource_size_t start, resource_size_t end,
-		     const char *type)
+int firmware_map_add(u64 start, u64 end, const char *type)
 {
 	struct firmware_map_entry *entry;
 
@@ -157,8 +160,7 @@
  *
  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
  **/
-int __init firmware_map_add_early(resource_size_t start, resource_size_t end,
-				  const char *type)
+int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 {
 	struct firmware_map_entry *entry;