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/*
* Userland implementation of clock_gettime() for 64 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
larl %r5,_vdso_data
cghi %r2,CLOCK_REALTIME
je 4f
cghi %r2,CLOCK_MONOTONIC
jne 9f
/* CLOCK_MONOTONIC */
ltgr %r3,%r3
jz 3f /* tp == NULL */
0: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
tmll %r4,0x0001 /* pending update ? loop */
jnz 0b
stck 48(%r15) /* Store TOD clock */
lg %r1,48(%r15)
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
mghi %r1,1000
srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */
alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime */
lg %r0,__VDSO_XTIME_SEC(%r5)
alg %r1,__VDSO_WTOM_NSEC(%r5) /* + wall_to_monotonic */
alg %r0,__VDSO_WTOM_SEC(%r5)
clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
jne 0b
larl %r5,10f
1: clg %r1,0(%r5)
jl 2f
slg %r1,0(%r5)
aghi %r0,1
j 1b
2: stg %r0,0(%r3) /* store tp->tv_sec */
stg %r1,8(%r3) /* store tp->tv_nsec */
3: lghi %r2,0
br %r14
/* CLOCK_REALTIME */
4: ltr %r3,%r3 /* tp == NULL */
jz 8f
5: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
tmll %r4,0x0001 /* pending update ? loop */
jnz 5b
stck 48(%r15) /* Store TOD clock */
lg %r1,48(%r15)
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
mghi %r1,1000
srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */
alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime */
lg %r0,__VDSO_XTIME_SEC(%r5)
clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
jne 5b
larl %r5,10f
6: clg %r1,0(%r5)
jl 7f
slg %r1,0(%r5)
aghi %r0,1
j 6b
7: stg %r0,0(%r3) /* store tp->tv_sec */
stg %r1,8(%r3) /* store tp->tv_nsec */
8: lghi %r2,0
br %r14
/* Fallback to system call */
9: lghi %r1,__NR_clock_gettime
svc 0
br %r14
10: .quad 1000000000
.cfi_endproc
.size __kernel_clock_gettime,.-__kernel_clock_gettime
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