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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_THREAD_CPUTIME_ID
je 9f
cghi %r2,-2 /* Per-thread CPUCLOCK with PID=0, VIRT=1 */
je 9f
cghi %r2,__CLOCK_MONOTONIC
jne 12f
/* 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 */
lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
lg %r0,__VDSO_WTOM_SEC(%r5)
lg %r1,48(%r15)
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
alg %r1,__VDSO_WTOM_NSEC(%r5)
srlg %r1,%r1,0(%r2) /* >> tk->shift */
clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
jne 0b
larl %r5,13f
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 */
lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
lg %r1,48(%r15)
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */
srlg %r1,%r1,0(%r2) /* >> tk->shift */
lg %r0,__VDSO_XTIME_SEC(%r5) /* tk->xtime_sec */
clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
jne 5b
larl %r5,13f
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
/* CLOCK_THREAD_CPUTIME_ID for this thread */
9: icm %r0,15,__VDSO_ECTG_OK(%r5)
jz 12f
ear %r2,%a4
llilh %r4,0x0100
sar %a4,%r4
lghi %r4,0
epsw %r5,0
sacf 512 /* Magic ectg instruction */
.insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4
tml %r5,0x4000
jo 11f
tml %r5,0x8000
jno 10f
sacf 256
j 11f
10: sacf 0
11: sar %a4,%r2
algr %r1,%r0 /* r1 = cputime as TOD value */
mghi %r1,1000 /* convert to nanoseconds */
srlg %r1,%r1,12 /* r1 = cputime in nanosec */
lgr %r4,%r1
larl %r5,13f
srlg %r1,%r1,9 /* divide by 1000000000 */
mlg %r0,8(%r5)
srlg %r0,%r0,11 /* r0 = tv_sec */
stg %r0,0(%r3)
msg %r0,0(%r5) /* calculate tv_nsec */
slgr %r4,%r0 /* r4 = tv_nsec */
stg %r4,8(%r3)
lghi %r2,0
br %r14
/* Fallback to system call */
12: lghi %r1,__NR_clock_gettime
svc 0
br %r14
13: .quad 1000000000
14: .quad 19342813113834067
.cfi_endproc
.size __kernel_clock_gettime,.-__kernel_clock_gettime
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