pc-bios/s390-ccw/start.S

   1 /*
   2  * First stage boot loader for virtio devices. The compiled output goes
   3  * into the pc-bios directory of qemu.
   4  *
   5  * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
   6  * Copyright 2013 IBM Corp.
   7  *
   8  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   9  * your option) any later version. See the COPYING file in the top-level
  10  * directory.
  11  */
  12
  13         .globl _start
  14 _start:
  15
  16 larl    %r15, stack + 0x8000    /* Set up stack */
  17 j       main                    /* And call C */
  18
  19 /*
  20  * void disabled_wait(void)
  21  *
  22  * stops the current guest cpu.
  23  */
  24         .globl disabled_wait
  25 disabled_wait:
  26         larl %r1,disabled_wait_psw
  27         lpswe   0(%r1)
  28
  29
  30 /*
  31  * void consume_sclp_int(void)
  32  *
  33  * eats one sclp interrupt
  34  */
  35         .globl consume_sclp_int
  36 consume_sclp_int:
  37         /* enable service interrupts in cr0 */
  38         stctg 0,0,0(15)
  39         oi 6(15), 0x2
  40         lctlg 0,0,0(15)
  41         /* prepare external call handler */
  42         larl %r1, external_new_code
  43         stg %r1, 0x1b8
  44         larl %r1, external_new_mask
  45         mvc 0x1b0(8),0(%r1)
  46         /* load enabled wait PSW */
  47         larl %r1, enabled_wait_psw
  48         lpswe 0(%r1)
  49
  50 external_new_code:
  51         /* disable service interrupts in cr0 */
  52         stctg 0,0,0(15)
  53         ni 6(15), 0xfd
  54         lctlg 0,0,0(15)
  55         br 14
  56
  57         .align  8
  58 disabled_wait_psw:
  59         .quad   0x0002000180000000,0x0000000000000000
  60 enabled_wait_psw:
  61         .quad   0x0302000180000000,0x0000000000000000
  62 external_new_mask:
  63         .quad   0x0000000180000000