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/*
* 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.
*/
#define STACK_SIZE 0x8000
#define STACK_FRAME_SIZE 160
.globl _start
_start:
larl %r15,stack + STACK_SIZE - STACK_FRAME_SIZE /* Set up stack */
/* clear bss */
larl %r2,bss_start_literal /* __bss_start might be unaligned ... */
lg %r2,0(%r2) /* ... so load it indirectly */
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
bss_start_literal:
.quad __bss_start
disabled_wait_psw:
.quad 0x0002000180000000,0x0000000000000000
enabled_wait_psw:
.quad 0x0302000180000000,0x0000000000000000
external_new_mask:
.quad 0x0000000180000000
io_new_mask:
.quad 0x0000000180000000
.bss
.align 8
stack:
.space STACK_SIZE
.size stack,STACK_SIZE
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