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/*
* Userland implementation of gettimeofday() for 32 bits processes in a
* s390 kernel for use in the vDSO
*
* Copyright IBM Corp. 2008
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (version 2 only)
* as published by the Free Software Foundation.
*/
#include <asm/vdso.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
.text
.align 4
.globl __kernel_gettimeofday
.type __kernel_gettimeofday,@function
__kernel_gettimeofday:
.cfi_startproc
ahi %r15,-16
basr %r5,0
0: al %r5,13f-0b(%r5) /* get &_vdso_data */
1: ltr %r3,%r3 /* check if tz is NULL */
je 2f
mvc 0(8,%r3),__VDSO_TIMEZONE(%r5)
2: ltr %r2,%r2 /* check if tv is NULL */
je 10f
l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
tml %r4,0x0001 /* pending update ? loop */
jnz 1b
stcke 0(%r15) /* Store TOD clock */
lm %r0,%r1,__VDSO_TS_END(%r5) /* TOD steering end time */
s %r0,1(%r15)
sl %r1,5(%r15)
brc 3,14f
ahi %r0,-1
14: ltr %r0,%r0 /* past end of steering? */
jm 16f
srdl %r0,15 /* 1 per 2^16 */
tm __VDSO_TS_DIR+3(%r5),0x01 /* steering direction? */
jz 15f
lcr %r0,%r0 /* negative TOD offset */
lcr %r1,%r1
je 15f
ahi %r0,-1
15: a %r0,1(%r15) /* add TOD timestamp */
al %r1,5(%r15)
brc 12,17f
ahi %r0,1
j 17f
16: lm %r0,%r1,1(%r15) /* load TOD timestamp */
17: s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
sl %r1,__VDSO_XTIME_STAMP+4(%r5)
brc 3,3f
ahi %r0,-1
3: ms %r0,__VDSO_TK_MULT(%r5) /* * tk->mult */
st %r0,0(%r15)
l %r0,__VDSO_TK_MULT(%r5)
ltr %r1,%r1
mr %r0,%r0
jnm 4f
a %r0,__VDSO_TK_MULT(%r5)
4: al %r0,0(%r15)
al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
al %r1,__VDSO_XTIME_NSEC+4(%r5)
brc 12,5f
ahi %r0,1
5: mvc 0(4,%r15),__VDSO_XTIME_SEC+4(%r5)
cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
jne 1b
l %r4,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
srdl %r0,0(%r4) /* >> tk->shift */
l %r4,0(%r15) /* get tv_sec from stack */
basr %r5,0
6: ltr %r0,%r0
jnz 7f
cl %r1,11f-6b(%r5)
jl 8f
7: ahi %r4,1
sl %r1,11f-6b(%r5)
brc 3,6b
ahi %r0,-1
j 6b
8: st %r4,0(%r2) /* store tv->tv_sec */
ltr %r1,%r1
m %r0,12f-6b(%r5)
jnm 9f
al %r0,12f-6b(%r5)
9: srl %r0,6
st %r0,4(%r2) /* store tv->tv_usec */
10: slr %r2,%r2
ahi %r15,16
br %r14
11: .long 1000000000
12: .long 274877907
13: .long _vdso_data - 0b
.cfi_endproc
.size __kernel_gettimeofday,.-__kernel_gettimeofday
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