diff --git a/target-arm/helper.c b/target-arm/helper.c
index 53527c2003..f5d6e68186 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -3531,6 +3531,8 @@ static int bad_mode_switch(CPUARMState *env, int mode)
     case ARM_CPU_MODE_IRQ:
     case ARM_CPU_MODE_FIQ:
         return 0;
+    case ARM_CPU_MODE_MON:
+        return !arm_is_secure(env);
     default:
         return 1;
     }