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 lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */ 87 lg %r1,1(%r15) 88 sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ 89 msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */ 90 alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */ 91 srlg %r1,%r1,0(%r2) /* >> tk->shift */ 92 lg %r0,__VDSO_XTIME_SEC(%r5) /* tk->xtime_sec */ 93 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */ 94 jne 5b 95 larl %r5,13f 966: clg %r1,0(%r5) 97 jl 7f 98 slg %r1,0(%r5) 99 aghi %r0,1 100 j 6b 1017: stg %r0,0(%r3) /* store tp->tv_sec */ 102 stg %r1,8(%r3) /* store tp->tv_nsec */ 103 lghi %r2,0 104 aghi %r15,16 105 br %r14 106 107 /* CPUCLOCK_VIRT for this thread */ 1089: icm %r0,15,__VDSO_ECTG_OK(%r5) 109 jz 12f 110 ear %r2,%a4 111 llilh %r4,0x0100 112 sar %a4,%r4 113 lghi %r4,0 114 epsw %r5,0 115 sacf 512 /* Magic ectg instruction */ 116 .insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4 117 tml %r5,0x4000 118 jo 11f 119 tml %r5,0x8000 120 jno 10f 121 sacf 256 122 j 11f 12310: sacf 0 12411: sar %a4,%r2 125 algr %r1,%r0 /* r1 = cputime as TOD value */ 126 mghi %r1,1000 /* convert to nanoseconds */ 127 srlg %r1,%r1,12 /* r1 = cputime in nanosec */ 128 lgr %r4,%r1 129 larl %r5,13f 130 srlg %r1,%r1,9 /* divide by 1000000000 */ 131 mlg %r0,8(%r5) 132 srlg %r0,%r0,11 /* r0 = tv_sec */ 133 stg %r0,0(%r3) 134 msg %r0,0(%r5) /* calculate tv_nsec */ 135 slgr %r4,%r0 /* r4 = tv_nsec */ 136 stg %r4,8(%r3) 137 lghi %r2,0 138 aghi %r15,16 139 br %r14 140 141 /* Fallback to system call */ 14212: lghi %r1,__NR_clock_gettime 143 svc 0 144 aghi %r15,16 145 br %r14 146 14713: .quad 1000000000 14814: .quad 19342813113834067 149 .cfi_endproc 150 .size __kernel_clock_gettime,.-__kernel_clock_gettime 151