diff --git a/target/arm/helper.c b/target/arm/helper.c
index 56e4b18ddb..7e822df596 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -56,6 +56,8 @@ static void v8m_security_lookup(CPUARMState *env, uint32_t address,
                                 V8M_SAttributes *sattrs);
 #endif
 
+static void switch_mode(CPUARMState *env, int mode);
+
 static int vfp_gdb_get_reg(CPUARMState *env, uint8_t *buf, int reg)
 {
     int nregs;
@@ -6316,7 +6318,7 @@ uint32_t HELPER(v7m_tt)(CPUARMState *env, uint32_t addr, uint32_t op)
     return 0;
 }
 
-void switch_mode(CPUARMState *env, int mode)
+static void switch_mode(CPUARMState *env, int mode)
 {
     ARMCPU *cpu = arm_env_get_cpu(env);
 
@@ -6338,7 +6340,7 @@ void aarch64_sync_64_to_32(CPUARMState *env)
 
 #else
 
-void switch_mode(CPUARMState *env, int mode)
+static void switch_mode(CPUARMState *env, int mode)
 {
     int old_mode;
     int i;
diff --git a/target/arm/internals.h b/target/arm/internals.h
index 276f2d8a8d..6b204fad51 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -145,7 +145,6 @@ static inline int bank_number(int mode)
     g_assert_not_reached();
 }
 
-void switch_mode(CPUARMState *, int);
 void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu);
 void arm_translate_init(void);