diff --git a/include/linux/mm.h b/include/linux/mm.h
index fb8b20e5d021..f24df9c0b9df 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1696,7 +1696,7 @@ extern void free_highmem_page(struct page *page);
 extern void adjust_managed_page_count(struct page *page, long count);
 extern void mem_init_print_info(const char *str);
 
-extern void reserve_bootmem_region(unsigned long start, unsigned long end);
+extern void reserve_bootmem_region(phys_addr_t start, phys_addr_t end);
 
 /* Free the reserved page into the buddy system, so it gets managed. */
 static inline void __free_reserved_page(struct page *page)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6cf5cadeaef7..99c1738684ec 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -951,7 +951,7 @@ static inline void init_reserved_page(unsigned long pfn)
  * marks the pages PageReserved. The remaining valid pages are later
  * sent to the buddy page allocator.
  */
-void __meminit reserve_bootmem_region(unsigned long start, unsigned long end)
+void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
 {
 	unsigned long start_pfn = PFN_DOWN(start);
 	unsigned long end_pfn = PFN_UP(end);