
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.

