2 * Userland implementation of clock_gettime() for 32 bits processes in a
3 * s390 kernel for use in the vDSO
5 * Copyright IBM Corp. 2008
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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.
13 #include <asm/asm-offsets.h>
14 #include <asm/unistd.h>
18 .globl __kernel_clock_gettime
19 .type __kernel_clock_gettime,@function
20 __kernel_clock_gettime:
23 0: al %r5,21f-0b(%r5) /* get &_vdso_data */
24 chi %r2,__CLOCK_REALTIME
26 chi %r2,__CLOCK_MONOTONIC
30 1: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
31 tml %r4,0x0001 /* pending update ? loop */
33 stck 24(%r15) /* Store TOD clock */
35 s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
36 sl %r1,__VDSO_XTIME_STAMP+4(%r5)
39 2: ms %r0,__VDSO_TK_MULT(%r5) /* * tk->mult */
41 l %r0,__VDSO_TK_MULT(%r5)
45 a %r0,__VDSO_TK_MULT(%r5)
47 al %r0,__VDSO_WTOM_NSEC(%r5)
48 al %r1,__VDSO_WTOM_NSEC+4(%r5)
51 5: l %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
52 srdl %r0,0(%r2) /* >> tk->shift */
53 l %r2,__VDSO_WTOM_SEC+4(%r5)
54 cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
66 8: st %r2,0(%r3) /* store tp->tv_sec */
67 st %r1,4(%r3) /* store tp->tv_nsec */
72 11: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */
73 tml %r4,0x0001 /* pending update ? loop */
75 stck 24(%r15) /* Store TOD clock */
77 s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
78 sl %r1,__VDSO_XTIME_STAMP+4(%r5)
81 12: ms %r0,__VDSO_TK_MULT(%r5) /* * tk->mult */
83 l %r0,__VDSO_TK_MULT(%r5)
87 a %r0,__VDSO_TK_MULT(%r5)
89 al %r0,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */
90 al %r1,__VDSO_XTIME_NSEC+4(%r5)
93 14: l %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
94 srdl %r0,0(%r2) /* >> tk->shift */
95 l %r2,__VDSO_XTIME_SEC+4(%r5)
96 cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */
108 17: st %r2,0(%r3) /* store tp->tv_sec */
109 st %r1,4(%r3) /* store tp->tv_nsec */
113 /* Fallback to system call */
114 19: lhi %r1,__NR_clock_gettime
119 21: .long _vdso_data - 0b
121 .size __kernel_clock_gettime,.-__kernel_clock_gettime