diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c
index 4201c743cc9fb33e17a52ae057940345d79e2681..c592d475b3d890a50061f8f3b265c4516457d749 100644
--- a/arch/microblaze/kernel/process.c
+++ b/arch/microblaze/kernel/process.c
@@ -235,7 +235,9 @@ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
 	regs->pc = pc;
 	regs->r1 = usp;
 	regs->pt_mode = 0;
+#ifdef CONFIG_MMU
 	regs->msr |= MSR_UMS;
+#endif
 }
 
 #ifdef CONFIG_MMU