1/*
 2 * Userland implementation of gettimeofday() for 64 bits processes in a
 3 * s390 kernel for use in the vDSO
 4 *
 5 *  Copyright IBM Corp. 2008
 6 *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
 7 *
 8 * This program is free software; you can redistribute it and/or modify
 9 * it under the terms of the GNU General Public License (version 2 only)
10 * as published by the Free Software Foundation.
11 */
12#include <asm/vdso.h>
13#include <asm/asm-offsets.h>
14#include <asm/unistd.h>
15
16	.text
17	.align 4
18	.globl __kernel_gettimeofday
19	.type  __kernel_gettimeofday,@function
20__kernel_gettimeofday:
21	.cfi_startproc
22	larl	%r5,_vdso_data
230:	ltgr	%r3,%r3				/* check if tz is NULL */
24	je	1f
25	mvc	0(8,%r3),__VDSO_TIMEZONE(%r5)
261:	ltgr	%r2,%r2				/* check if tv is NULL */
27	je	4f
28	lg	%r4,__VDSO_UPD_COUNT(%r5)	/* load update counter */
29	tmll	%r4,0x0001			/* pending update ? loop */
30	jnz	0b
31	stck	48(%r15)			/* Store TOD clock */
32	lg	%r1,48(%r15)
33	sg	%r1,__VDSO_XTIME_STAMP(%r5)	/* TOD - cycle_last */
34	msgf	%r1,__VDSO_TK_MULT(%r5)		/*  * tk->mult */
35	alg	%r1,__VDSO_XTIME_NSEC(%r5)	/*  + tk->xtime_nsec */
36	lg	%r0,__VDSO_XTIME_SEC(%r5)	/* tk->xtime_sec */
37	clg	%r4,__VDSO_UPD_COUNT(%r5)	/* check update counter */
38	jne	0b
39	lgf	%r5,__VDSO_TK_SHIFT(%r5)	/* Timekeeper shift */
40	srlg	%r1,%r1,0(%r5)			/*  >> tk->shift */
41	larl	%r5,5f
422:	clg	%r1,0(%r5)
43	jl	3f
44	slg	%r1,0(%r5)
45	aghi	%r0,1
46	j	2b
473:	stg	%r0,0(%r2)			/* store tv->tv_sec */
48	slgr	%r0,%r0				/* tv_nsec -> tv_usec */
49	ml	%r0,8(%r5)
50	srlg	%r0,%r0,6
51	stg	%r0,8(%r2)			/* store tv->tv_usec */
524:	lghi	%r2,0
53	br	%r14
545:	.quad	1000000000
55	.long	274877907
56	.cfi_endproc
57	.size	__kernel_gettimeofday,.-__kernel_gettimeofday