Writing to these registers may raise an interrupt request. Actually,
this prevents the milkymist board from starting.

Cc: qemu-stable@nongnu.org
Signed-off-by: Michael Walle <michael@walle.cc>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
 target/lm32/op_helper.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/target/lm32/op_helper.c b/target/lm32/op_helper.c
index 577f8306e3..234d55e056 100644
--- a/target/lm32/op_helper.c
+++ b/target/lm32/op_helper.c
@@ -102,12 +102,16 @@ void HELPER(wcsr_dc)(CPULM32State *env, uint32_t dc)
 
 void HELPER(wcsr_im)(CPULM32State *env, uint32_t im)
 {
+    qemu_mutex_lock_iothread();
     lm32_pic_set_im(env->pic_state, im);
+    qemu_mutex_unlock_iothread();
 }
 
 void HELPER(wcsr_ip)(CPULM32State *env, uint32_t im)
 {
+    qemu_mutex_lock_iothread();
     lm32_pic_set_ip(env->pic_state, im);
+    qemu_mutex_unlock_iothread();
 }
 
 void HELPER(wcsr_jtx)(CPULM32State *env, uint32_t jtx)
-- 
2.11.0