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/*
* Userland implementation of clock_gettime() 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_clock_gettime
.type __kernel_clock_gettime,@function
__kernel_clock_gettime:
.cfi_startproc
ahi %r15,-16
basr %r5,0
0: al %r5,21f-0b(%r5) /* get &_vdso_data */
chi %r2,__CLOCK_REALTIME_COARSE
je 10f
chi %r2,__CLOCK_REALTIME
je 11f
chi %r2,__CLOCK_MONOTONIC_COARSE
je 9f
chi %r2,__CLOCK_MONOTONIC
jne 19f
/* CLOCK_MONOTONIC */
1: 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,%r1,1(%r15)
s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
sl %r1,__VDSO_XTIME_STAMP+4(%r5)
brc 3,2f
ahi %r0,-1
2: ms %r0,__VDSO_TK_MULT(%r5) /* * tk->mult */
lr %r2,%r0
l %r0,__VDSO_TK_MULT(%r5)
ltr %r1,%r1
mr %r0,%r0
jnm 3f
a %r0,__VDSO_TK_MULT(%r5)
3: alr %r0,%r2
al %r0,__VDSO_WTOM_NSEC(%r5)
al %r1,__VDSO_WTOM_NSEC+4(%r5)
brc 12,5f
ahi %r0,1
5: l %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
srdl %r0,0(%r2) /* >> tk->shift */
l %r2,__VDSO_WTOM_SEC+4(%r5)
cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
jne 1b
basr %r5,0
6: ltr %r0,%r0
jnz 7f
cl %r1,20f-6b(%r5)
jl 8f
7: ahi %r2,1
sl %r1,20f-6b(%r5)
brc 3,6b
ahi %r0,-1
j 6b
8: st %r2,0(%r3) /* store tp->tv_sec */
st %r1,4(%r3) /* store tp->tv_nsec */
lhi %r2,0
ahi %r15,16
br %r14
/* CLOCK_MONOTONIC_COARSE */
9: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
tml %r4,0x0001 /* pending update ? loop */
jnz 9b
l %r2,__VDSO_WTOM_CRS_SEC+4(%r5)
l %r1,__VDSO_WTOM_CRS_NSEC+4(%r5)
cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
jne 9b
j 8b
/* CLOCK_REALTIME_COARSE */
10: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
tml %r4,0x0001 /* pending update ? loop */
jnz 10b
l %r2,__VDSO_XTIME_CRS_SEC+4(%r5)
l %r1,__VDSO_XTIME_CRS_NSEC+4(%r5)
cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
jne 10b
j 17f
/* CLOCK_REALTIME */
11: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
tml %r4,0x0001 /* pending update ? loop */
jnz 11b
stcke 0(%r15) /* Store TOD clock */
lm %r0,%r1,__VDSO_TS_END(%r5) /* TOD steering end time */
s %r0,1(%r15) /* no - ts_steering_end */
sl %r1,5(%r15)
brc 3,22f
ahi %r0,-1
22: ltr %r0,%r0 /* past end of steering? */
jm 24f
srdl %r0,15 /* 1 per 2^16 */
tm __VDSO_TS_DIR+3(%r5),0x01 /* steering direction? */
jz 23f
lcr %r0,%r0 /* negative TOD offset */
lcr %r1,%r1
je 23f
ahi %r0,-1
23: a %r0,1(%r15) /* add TOD timestamp */
al %r1,5(%r15)
brc 12,25f
ahi %r0,1
j 25f
24: lm %r0,%r1,1(%r15) /* load TOD timestamp */
25: s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
sl %r1,__VDSO_XTIME_STAMP+4(%r5)
brc 3,12f
ahi %r0,-1
12: ms %r0,__VDSO_TK_MULT(%r5) /* * tk->mult */
lr %r2,%r0
l %r0,__VDSO_TK_MULT(%r5)
ltr %r1,%r1
mr %r0,%r0
jnm 13f
a %r0,__VDSO_TK_MULT(%r5)
13: alr %r0,%r2
al %r0,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */
al %r1,__VDSO_XTIME_NSEC+4(%r5)
brc 12,14f
ahi %r0,1
14: l %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
srdl %r0,0(%r2) /* >> tk->shift */
l %r2,__VDSO_XTIME_SEC+4(%r5)
cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
jne 11b
basr %r5,0
15: ltr %r0,%r0
jnz 16f
cl %r1,20f-15b(%r5)
jl 17f
16: ahi %r2,1
sl %r1,20f-15b(%r5)
brc 3,15b
ahi %r0,-1
j 15b
17: st %r2,0(%r3) /* store tp->tv_sec */
st %r1,4(%r3) /* store tp->tv_nsec */
lhi %r2,0
ahi %r15,16
br %r14
/* Fallback to system call */
19: lhi %r1,__NR_clock_gettime
svc 0
ahi %r15,16
br %r14
20: .long 1000000000
21: .long _vdso_data - 0b
.cfi_endproc
.size __kernel_clock_gettime,.-__kernel_clock_gettime
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