diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index f7457fea6de8..2b7996401b0f 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -124,7 +124,7 @@ int valid_phys_addr_range(unsigned long addr, size_t size)
 {
 	if (addr < PHYS_OFFSET)
 		return 0;
-	if (addr + size >= __pa(high_memory - 1))
+	if (addr + size > __pa(high_memory - 1) + 1)
 		return 0;
 
 	return 1;