| /* |
| * First stage boot loader for virtio devices. The compiled output goes |
| * into the pc-bios directory of qemu. |
| * |
| * Copyright (c) 2013 Alexander Graf <agraf@suse.de> |
| * Copyright IBM Corp. 2013, 2017 |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2 or (at |
| * your option) any later version. See the COPYING file in the top-level |
| * directory. |
| */ |
| |
| .globl _start |
| _start: |
| |
| larl %r15, stack + 0x8000 /* Set up stack */ |
| |
| /* clear bss */ |
| larl %r2, __bss_start |
| larl %r3, _end |
| slgr %r3, %r2 /* get sizeof bss */ |
| ltgr %r3,%r3 /* bss empty? */ |
| jz done |
| aghi %r3,-1 |
| srlg %r4,%r3,8 /* how many 256 byte chunks? */ |
| ltgr %r4,%r4 |
| lgr %r1,%r2 |
| jz remainder |
| loop: |
| xc 0(256,%r1),0(%r1) |
| la %r1,256(%r1) |
| brctg %r4,loop |
| remainder: |
| larl %r2,memsetxc |
| ex %r3,0(%r2) |
| done: |
| /* set up a pgm exception disabled wait psw */ |
| larl %r2, disabled_wait_psw |
| mvc 0x01d0(16), 0(%r2) |
| j main /* And call C */ |
| |
| memsetxc: |
| xc 0(1,%r1),0(%r1) |
| |
| |
| /* |
| * void disabled_wait(void) |
| * |
| * stops the current guest cpu. |
| */ |
| .globl disabled_wait |
| disabled_wait: |
| larl %r1,disabled_wait_psw |
| lpswe 0(%r1) |
| 1: j 1b |
| |
| |
| /* |
| * void consume_sclp_int(void) |
| * |
| * eats one sclp interrupt |
| */ |
| .globl consume_sclp_int |
| consume_sclp_int: |
| /* enable service interrupts in cr0 */ |
| stctg %c0,%c0,0(%r15) |
| oi 6(%r15),0x2 |
| lctlg %c0,%c0,0(%r15) |
| /* prepare external call handler */ |
| larl %r1, external_new_code |
| stg %r1, 0x1b8 |
| larl %r1, external_new_mask |
| mvc 0x1b0(8),0(%r1) |
| /* load enabled wait PSW */ |
| larl %r1, enabled_wait_psw |
| lpswe 0(%r1) |
| |
| /* |
| * void consume_io_int(void) |
| * |
| * eats one I/O interrupt |
| */ |
| .globl consume_io_int |
| consume_io_int: |
| /* enable I/O interrupts in cr6 */ |
| stctg %c6,%c6,0(%r15) |
| oi 4(%r15), 0xff |
| lctlg %c6,%c6,0(%r15) |
| /* prepare i/o call handler */ |
| larl %r1, io_new_code |
| stg %r1, 0x1f8 |
| larl %r1, io_new_mask |
| mvc 0x1f0(8),0(%r1) |
| /* load enabled wait PSW */ |
| larl %r1, enabled_wait_psw |
| lpswe 0(%r1) |
| |
| external_new_code: |
| /* disable service interrupts in cr0 */ |
| stctg %c0,%c0,0(%r15) |
| ni 6(%r15),0xfd |
| lctlg %c0,%c0,0(%r15) |
| br %r14 |
| |
| io_new_code: |
| /* disable I/O interrupts in cr6 */ |
| stctg %c6,%c6,0(%r15) |
| ni 4(%r15), 0x00 |
| lctlg %c6,%c6,0(%r15) |
| br %r14 |
| |
| .align 8 |
| disabled_wait_psw: |
| .quad 0x0002000180000000,0x0000000000000000 |
| enabled_wait_psw: |
| .quad 0x0302000180000000,0x0000000000000000 |
| external_new_mask: |
| .quad 0x0000000180000000 |
| io_new_mask: |
| .quad 0x0000000180000000 |
