These interfaces allow a device driver to send signals to a process in a multithread-safe manner.
void *proc_ref(void);
proc_ref(9F) retrieves an unambiguous reference to the process of the current thread for signaling purposes.
int proc_signal(void *pref, int sig);
proc_signal(9F) sends the signal indicated in sig to the process defined by pref that has been referenced by proc_ref(9F).
void proc_unref(void *pref);
proc_unref(9F) unreferences the process defined by pref.