1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Userland implementation of gettimeofday() for 64 bits processes in a
4 * s390 kernel for use in the vDSO
5 *
6 *  Copyright IBM Corp. 2008
7 *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
8 */
9#include <asm/vdso.h>
10#include <asm/asm-offsets.h>
11#include <asm/unistd.h>
12#include <asm/dwarf.h>
13
14	.text
15	.align 4
16	.globl __kernel_gettimeofday
17	.type  __kernel_gettimeofday,@function
18__kernel_gettimeofday:
19	CFI_STARTPROC
20	aghi	%r15,-16
21	CFI_ADJUST_CFA_OFFSET 16
22	CFI_VAL_OFFSET 15, -160
23	larl	%r5,_vdso_data
240:	ltgr	%r3,%r3				/* check if tz is NULL */
25	je	1f
26	mvc	0(8,%r3),__VDSO_TIMEZONE(%r5)
271:	ltgr	%r2,%r2				/* check if tv is NULL */
28	je	4f
29	lg	%r4,__VDSO_UPD_COUNT(%r5)	/* load update counter */
30	tmll	%r4,0x0001			/* pending update ? loop */
31	jnz	0b
32	stcke	0(%r15)				/* Store TOD clock */
33	lg	%r1,1(%r15)
34	lg	%r0,__VDSO_TS_END(%r5)		/* TOD steering end time */
35	slgr	%r0,%r1				/* now - ts_steering_end */
36	ltgr	%r0,%r0				/* past end of steering ? */
37	jm	6f
38	srlg	%r0,%r0,15			/* 1 per 2^16 */
39	tm	__VDSO_TS_DIR+3(%r5),0x01	/* steering direction? */
40	jz	7f
41	lcgr	%r0,%r0				/* negative TOD offset */
427:	algr	%r1,%r0				/* add steering offset */
436:	sg	%r1,__VDSO_XTIME_STAMP(%r5)	/* TOD - cycle_last */
44	msgf	%r1,__VDSO_TK_MULT(%r5)		/*  * tk->mult */
45	alg	%r1,__VDSO_XTIME_NSEC(%r5)	/*  + tk->xtime_nsec */
46	lg	%r0,__VDSO_XTIME_SEC(%r5)	/* tk->xtime_sec */
47	clg	%r4,__VDSO_UPD_COUNT(%r5)	/* check update counter */
48	jne	0b
49	lgf	%r5,__VDSO_TK_SHIFT(%r5)	/* Timekeeper shift */
50	srlg	%r1,%r1,0(%r5)			/*  >> tk->shift */
51	larl	%r5,5f
522:	clg	%r1,0(%r5)
53	jl	3f
54	slg	%r1,0(%r5)
55	aghi	%r0,1
56	j	2b
573:	stg	%r0,0(%r2)			/* store tv->tv_sec */
58	slgr	%r0,%r0				/* tv_nsec -> tv_usec */
59	ml	%r0,8(%r5)
60	srlg	%r0,%r0,6
61	stg	%r0,8(%r2)			/* store tv->tv_usec */
624:	lghi	%r2,0
63	aghi	%r15,16
64	CFI_ADJUST_CFA_OFFSET -16
65	CFI_RESTORE 15
66	br	%r14
67	CFI_ENDPROC
685:	.quad	1000000000
69	.long	274877907
70	.size	__kernel_gettimeofday,.-__kernel_gettimeofday
71