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 larl %r5,_vdso_data 23 cghi %r2,CLOCK_REALTIME 24 je 4f 25 cghi %r2,-2 /* CLOCK_THREAD_CPUTIME_ID for this thread */ 26 je 9f 27 cghi %r2,CLOCK_MONOTONIC 28 jne 12f 29 30 /* CLOCK_MONOTONIC */ 31 ltgr %r3,%r3 32 jz 3f /* tp == NULL */ 330: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ 34 tmll %r4,0x0001 /* pending update ? loop */ 35 jnz 0b 36 stck 48(%r15) /* Store TOD clock */ 37 lg %r1,48(%r15) 38 sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ 39 msgf %r1,__VDSO_NTP_MULT(%r5) /* * NTP adjustment */ 40 srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */ 41 alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime */ 42 lg %r0,__VDSO_XTIME_SEC(%r5) 43 alg %r1,__VDSO_WTOM_NSEC(%r5) /* + wall_to_monotonic */ 44 alg %r0,__VDSO_WTOM_SEC(%r5) 45 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */ 46 jne 0b 47 larl %r5,13f 481: clg %r1,0(%r5) 49 jl 2f 50 slg %r1,0(%r5) 51 aghi %r0,1 52 j 1b 532: stg %r0,0(%r3) /* store tp->tv_sec */ 54 stg %r1,8(%r3) /* store tp->tv_nsec */ 553: lghi %r2,0 56 br %r14 57 58 /* CLOCK_REALTIME */ 594: ltr %r3,%r3 /* tp == NULL */ 60 jz 8f 615: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */ 62 tmll %r4,0x0001 /* pending update ? loop */ 63 jnz 5b 64 stck 48(%r15) /* Store TOD clock */ 65 lg %r1,48(%r15) 66 sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ 67 msgf %r1,__VDSO_NTP_MULT(%r5) /* * NTP adjustment */ 68 srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */ 69 alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime */ 70 lg %r0,__VDSO_XTIME_SEC(%r5) 71 clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */ 72 jne 5b 73 larl %r5,13f 746: clg %r1,0(%r5) 75 jl 7f 76 slg %r1,0(%r5) 77 aghi %r0,1 78 j 6b 797: stg %r0,0(%r3) /* store tp->tv_sec */ 80 stg %r1,8(%r3) /* store tp->tv_nsec */ 818: lghi %r2,0 82 br %r14 83 84 /* CLOCK_THREAD_CPUTIME_ID for this thread */ 859: icm %r0,15,__VDSO_ECTG_OK(%r5) 86 jz 12f 87 ear %r2,%a4 88 llilh %r4,0x0100 89 sar %a4,%r4 90 lghi %r4,0 91 epsw %r5,0 92 sacf 512 /* Magic ectg instruction */ 93 .insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4 94 tml %r5,0x4000 95 jo 11f 96 tml %r5,0x8000 97 jno 10f 98 sacf 256 99 j 11f 10010: sacf 0 10111: sar %a4,%r2 102 algr %r1,%r0 /* r1 = cputime as TOD value */ 103 mghi %r1,1000 /* convert to nanoseconds */ 104 srlg %r1,%r1,12 /* r1 = cputime in nanosec */ 105 lgr %r4,%r1 106 larl %r5,13f 107 srlg %r1,%r1,9 /* divide by 1000000000 */ 108 mlg %r0,8(%r5) 109 srlg %r0,%r0,11 /* r0 = tv_sec */ 110 stg %r0,0(%r3) 111 msg %r0,0(%r5) /* calculate tv_nsec */ 112 slgr %r4,%r0 /* r4 = tv_nsec */ 113 stg %r4,8(%r3) 114 lghi %r2,0 115 br %r14 116 117 /* Fallback to system call */ 11812: lghi %r1,__NR_clock_gettime 119 svc 0 120 br %r14 121 12213: .quad 1000000000 12314: .quad 19342813113834067 124 .cfi_endproc 125 .size __kernel_clock_gettime,.-__kernel_clock_gettime 126