1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Userland implementation of clock_gettime() for 64 bits processes in a
4 * s390 kernel for use in the vDSO
6 * Copyright IBM Corp. 2008
7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
10 #include <asm/asm-offsets.h>
11 #include <asm/unistd.h>
15 .globl __kernel_clock_gettime
16 .type __kernel_clock_gettime,@function
17 __kernel_clock_gettime:
21 cghi %r2,__CLOCK_REALTIME_COARSE
23 cghi %r2,__CLOCK_REALTIME
25 cghi %r2,-3 /* Per-thread CPUCLOCK with PID=0, VIRT=1 */
27 cghi %r2,__CLOCK_MONOTONIC_COARSE
29 cghi %r2,__CLOCK_MONOTONIC
33 0: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
34 tmll %r4,0x0001 /* pending update ? loop */
36 stcke 0(%r15) /* Store TOD clock */
37 lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
38 lg %r0,__VDSO_WTOM_SEC(%r5)
40 sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
41 msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
42 alg %r1,__VDSO_WTOM_NSEC(%r5)
43 srlg %r1,%r1,0(%r2) /* >> tk->shift */
44 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
52 2: stg %r0,0(%r3) /* store tp->tv_sec */
53 stg %r1,8(%r3) /* store tp->tv_nsec */
58 /* CLOCK_MONOTONIC_COARSE */
59 3: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
60 tmll %r4,0x0001 /* pending update ? loop */
62 lg %r0,__VDSO_WTOM_CRS_SEC(%r5)
63 lg %r1,__VDSO_WTOM_CRS_NSEC(%r5)
64 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
68 /* CLOCK_REALTIME_COARSE */
69 4: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
70 tmll %r4,0x0001 /* pending update ? loop */
72 lg %r0,__VDSO_XTIME_CRS_SEC(%r5)
73 lg %r1,__VDSO_XTIME_CRS_NSEC(%r5)
74 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
79 5: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
80 tmll %r4,0x0001 /* pending update ? loop */
82 stcke 0(%r15) /* Store TOD clock */
84 lg %r0,__VDSO_TS_END(%r5) /* TOD steering end time */
85 slgr %r0,%r1 /* now - ts_steering_end */
86 ltgr %r0,%r0 /* past end of steering ? */
88 srlg %r0,%r0,15 /* 1 per 2^16 */
89 tm __VDSO_TS_DIR+3(%r5),0x01 /* steering direction? */
91 lcgr %r0,%r0 /* negative TOD offset */
92 18: algr %r1,%r0 /* add steering offset */
93 17: lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
94 sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
95 msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
96 alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */
97 srlg %r1,%r1,0(%r2) /* >> tk->shift */
98 lg %r0,__VDSO_XTIME_SEC(%r5) /* tk->xtime_sec */
99 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
107 7: stg %r0,0(%r3) /* store tp->tv_sec */
108 stg %r1,8(%r3) /* store tp->tv_nsec */
113 /* CPUCLOCK_VIRT for this thread */
115 icm %r0,15,__VDSO_ECTG_OK(%r5)
117 sacf 256 /* Magic ectg instruction */
118 .insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4
120 algr %r1,%r0 /* r1 = cputime as TOD value */
121 mghi %r1,1000 /* convert to nanoseconds */
122 srlg %r1,%r1,12 /* r1 = cputime in nanosec */
125 srlg %r1,%r1,9 /* divide by 1000000000 */
127 srlg %r0,%r0,11 /* r0 = tv_sec */
129 msg %r0,0(%r5) /* calculate tv_nsec */
130 slgr %r4,%r0 /* r4 = tv_nsec */
136 /* Fallback to system call */
137 12: lghi %r1,__NR_clock_gettime
143 14: .quad 19342813113834067
145 .size __kernel_clock_gettime,.-__kernel_clock_gettime