OpenBSD/hppa -- syscall System call sequence: USER KERNEL ldil L%SYSCALLGATE, %r1 ble 4(%sr7, %r1) ldi SYS_open, t1 gate,n $bsd_syscall, %r0 . . . $bsd_syscall mfctl %eiem, %r1 mtctl %r0, %eiem mtsp %r0, %sr1 Privilege level elevation is a two steps process.