diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index aee6031230306a934747c64edb4b61f6928e9e8b..b2d26d9d8489c8e8b6bba01adee0c573fd6564f8 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -186,7 +186,7 @@ static void __init setup_bootmem(void)
 	BUG_ON(mem_size == 0);
 
 	set_max_mapnr(PFN_DOWN(mem_size));
-	max_low_pfn = pfn_base + PFN_DOWN(mem_size);
+	max_low_pfn = memblock_end_of_DRAM();
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	setup_initrd();