#define switch_mm(prev,next,tsk) do { } while (0)
#define deactivate_mm(tsk,mm) do { } while (0)
#define activate_mm(prev,next) do { } while (0)
#define switch_mm(prev,next,tsk) do { } while (0)
#define deactivate_mm(tsk,mm) do { } while (0)
#define activate_mm(prev,next) do { } while (0)