diff --git a/arch/nds32/kernel/head.S b/arch/nds32/kernel/head.S
index 1ce653d35d9360b9499e6ef007eff42294237602..2c8aac6201be4708295cdb35d9d7e62b25211ff9 100644
--- a/arch/nds32/kernel/head.S
+++ b/arch/nds32/kernel/head.S
@@ -123,14 +123,7 @@ _image_size_check:
         andi    $r0, $r0, MMU_CFG_mskTBS
         srli    $r6, $r6, MMU_CFG_offTBW
         srli    $r0, $r0, MMU_CFG_offTBS
-        /*
-         * we just map the kernel to the maximum way - 1 of tlb
-         * reserver one way for UART VA mapping
-         * it will cause page fault if UART mapping cover the kernel mapping
-         *
-         * direct mapping is not supported now.
-         */
-        beqz    $r6, __error                 ! MMU_CFG.TBW = 0 is direct mappin
+	addi    $r6, $r6, #0x1               ! MMU_CFG.TBW value -> meaning
         addi    $r0, $r0, #0x2               ! MMU_CFG.TBS value -> meaning
         sll     $r0, $r6, $r0                ! entries = k-way * n-set
         mul     $r6, $r0, $r5                ! max size = entries * page size