1/* 2 * Userland implementation of clock_gettime() 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_clock_gettime 19 .type __kernel_clock_gettime,@function 20__kernel_clock_gettime: 21 .cfi_startproc 22 aghi %r15,-16 23 larl %r5,_vdso_data 24 cghi %r2,__CLOCK_REALTIME_COARSE 25 je 4f 26 cghi %r2,__CLOCK_REALTIME 27 je 5f 28 cghi %r2,-3 /* Per-thread CPUCLOCK with PID=0, VIRT=1 */ 29 je 9f 30 cghi %r2,__CLOCK_MONOTONIC_COARSE 31 je 3f 32 cghi %r2,__CLOCK_MONOTONIC 33 jne 12f 34 35 /* CLOCK_MONOTONIC */ 360: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ 37 tmll %r4,0x0001 /* pending update ? loop */ 38 jnz 0b 39 stcke 0(%r15) /* Store TOD clock */ 40 lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */ 41 lg %r0,__VDSO_WTOM_SEC(%r5) 42 lg %r1,1(%r15) 43 sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ 44 msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */ 45 alg %r1,__VDSO_WTOM_NSEC(%r5) 46 srlg %r1,%r1,0(%r2) /* >> tk->shift */ 47 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */ 48 jne 0b 49 larl %r5,13f 501: clg %r1,0(%r5) 51 jl 2f 52 slg %r1,0(%r5) 53 aghi %r0,1 54 j 1b 552: stg %r0,0(%r3) /* store tp->tv_sec */ 56 stg %r1,8(%r3) /* store tp->tv_nsec */ 57 lghi %r2,0 58 aghi %r15,16 59 br %r14 60 61 /* CLOCK_MONOTONIC_COARSE */ 623: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ 63 tmll %r4,0x0001 /* pending update ? loop */ 64 jnz 3b 65 lg %r0,__VDSO_WTOM_CRS_SEC(%r5) 66 lg %r1,__VDSO_WTOM_CRS_NSEC(%r5) 67 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */ 68 jne 3b 69 j 2b 70 71 /* CLOCK_REALTIME_COARSE */ 724: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ 73 tmll %r4,0x0001 /* pending update ? loop */ 74 jnz 4b 75 lg %r0,__VDSO_XTIME_CRS_SEC(%r5) 76 lg %r1,__VDSO_XTIME_CRS_NSEC(%r5) 77 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */ 78 jne 4b 79 j 7f 80 81 /* CLOCK_REALTIME */ 825: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ 83 tmll %r4,0x0001 /* pending update ? loop */ 84 jnz 5b 85 stcke 0(%r15) /* Store TOD clock */ 86 lg %r1,1(%r15) 87 lg %r0,__VDSO_TS_END(%r5) /* TOD steering end time */ 88 slgr %r0,%r1 /* now - ts_steering_end */ 89 ltgr %r0,%r0 /* past end of steering ? */ 90 jm 17f 91 srlg %r0,%r0,15 /* 1 per 2^16 */ 92 tm __VDSO_TS_DIR+3(%r5),0x01 /* steering direction? */ 93 jz 18f 94 lcgr %r0,%r0 /* negative TOD offset */ 9518: algr %r1,%r0 /* add steering offset */ 9617: lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */ 97 sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ 98 msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */ 99 alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */ 100 srlg %r1,%r1,0(%r2) /* >> tk->shift */ 101 lg %r0,__VDSO_XTIME_SEC(%r5) /* tk->xtime_sec */ 102 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */ 103 jne 5b 104 larl %r5,13f 1056: clg %r1,0(%r5) 106 jl 7f 107 slg %r1,0(%r5) 108 aghi %r0,1 109 j 6b 1107: stg %r0,0(%r3) /* store tp->tv_sec */ 111 stg %r1,8(%r3) /* store tp->tv_nsec */ 112 lghi %r2,0 113 aghi %r15,16 114 br %r14 115 116 /* CPUCLOCK_VIRT for this thread */ 1179: icm %r0,15,__VDSO_ECTG_OK(%r5) 118 jz 12f 119 ear %r2,%a4 120 llilh %r4,0x0100 121 sar %a4,%r4 122 lghi %r4,0 123 epsw %r5,0 124 sacf 512 /* Magic ectg instruction */ 125 .insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4 126 tml %r5,0x4000 127 jo 11f 128 tml %r5,0x8000 129 jno 10f 130 sacf 256 131 j 11f 13210: sacf 0 13311: sar %a4,%r2 134 algr %r1,%r0 /* r1 = cputime as TOD value */ 135 mghi %r1,1000 /* convert to nanoseconds */ 136 srlg %r1,%r1,12 /* r1 = cputime in nanosec */ 137 lgr %r4,%r1 138 larl %r5,13f 139 srlg %r1,%r1,9 /* divide by 1000000000 */ 140 mlg %r0,8(%r5) 141 srlg %r0,%r0,11 /* r0 = tv_sec */ 142 stg %r0,0(%r3) 143 msg %r0,0(%r5) /* calculate tv_nsec */ 144 slgr %r4,%r0 /* r4 = tv_nsec */ 145 stg %r4,8(%r3) 146 lghi %r2,0 147 aghi %r15,16 148 br %r14 149 150 /* Fallback to system call */ 15112: lghi %r1,__NR_clock_gettime 152 svc 0 153 aghi %r15,16 154 br %r14 155 15613: .quad 1000000000 15714: .quad 19342813113834067 158 .cfi_endproc 159 .size __kernel_clock_gettime,.-__kernel_clock_gettime 160