1/* 2 * Userland implementation of clock_gettime() for 32 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 basr %r5,0 230: al %r5,21f-0b(%r5) /* get &_vdso_data */ 24 chi %r2,CLOCK_REALTIME 25 je 10f 26 chi %r2,CLOCK_MONOTONIC 27 jne 19f 28 29 /* CLOCK_MONOTONIC */ 30 ltr %r3,%r3 31 jz 9f /* tp == NULL */ 321: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */ 33 tml %r4,0x0001 /* pending update ? loop */ 34 jnz 1b 35 stck 24(%r15) /* Store TOD clock */ 36 lm %r0,%r1,24(%r15) 37 s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ 38 sl %r1,__VDSO_XTIME_STAMP+4(%r5) 39 brc 3,2f 40 ahi %r0,-1 412: ms %r0,__VDSO_NTP_MULT(%r5) /* cyc2ns(clock,cycle_delta) */ 42 lr %r2,%r0 43 l %r0,__VDSO_NTP_MULT(%r5) 44 ltr %r1,%r1 45 mr %r0,%r0 46 jnm 3f 47 a %r0,__VDSO_NTP_MULT(%r5) 483: alr %r0,%r2 49 srdl %r0,12 50 al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */ 51 al %r1,__VDSO_XTIME_NSEC+4(%r5) 52 brc 12,4f 53 ahi %r0,1 544: l %r2,__VDSO_XTIME_SEC+4(%r5) 55 al %r0,__VDSO_WTOM_NSEC(%r5) /* + wall_to_monotonic */ 56 al %r1,__VDSO_WTOM_NSEC+4(%r5) 57 brc 12,5f 58 ahi %r0,1 595: al %r2,__VDSO_WTOM_SEC+4(%r5) 60 cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */ 61 jne 1b 62 basr %r5,0 636: ltr %r0,%r0 64 jnz 7f 65 cl %r1,20f-6b(%r5) 66 jl 8f 677: ahi %r2,1 68 sl %r1,20f-6b(%r5) 69 brc 3,6b 70 ahi %r0,-1 71 j 6b 728: st %r2,0(%r3) /* store tp->tv_sec */ 73 st %r1,4(%r3) /* store tp->tv_nsec */ 749: lhi %r2,0 75 br %r14 76 77 /* CLOCK_REALTIME */ 7810: ltr %r3,%r3 /* tp == NULL */ 79 jz 18f 8011: l %r4,__VDSO_UPD_COUNT+4(%r5) /* load update counter */ 81 tml %r4,0x0001 /* pending update ? loop */ 82 jnz 11b 83 stck 24(%r15) /* Store TOD clock */ 84 lm %r0,%r1,24(%r15) 85 s %r0,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */ 86 sl %r1,__VDSO_XTIME_STAMP+4(%r5) 87 brc 3,12f 88 ahi %r0,-1 8912: ms %r0,__VDSO_NTP_MULT(%r5) /* cyc2ns(clock,cycle_delta) */ 90 lr %r2,%r0 91 l %r0,__VDSO_NTP_MULT(%r5) 92 ltr %r1,%r1 93 mr %r0,%r0 94 jnm 13f 95 a %r0,__VDSO_NTP_MULT(%r5) 9613: alr %r0,%r2 97 srdl %r0,12 98 al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */ 99 al %r1,__VDSO_XTIME_NSEC+4(%r5) 100 brc 12,14f 101 ahi %r0,1 10214: l %r2,__VDSO_XTIME_SEC+4(%r5) 103 cl %r4,__VDSO_UPD_COUNT+4(%r5) /* check update counter */ 104 jne 11b 105 basr %r5,0 10615: ltr %r0,%r0 107 jnz 16f 108 cl %r1,20f-15b(%r5) 109 jl 17f 11016: ahi %r2,1 111 sl %r1,20f-15b(%r5) 112 brc 3,15b 113 ahi %r0,-1 114 j 15b 11517: st %r2,0(%r3) /* store tp->tv_sec */ 116 st %r1,4(%r3) /* store tp->tv_nsec */ 11718: lhi %r2,0 118 br %r14 119 120 /* Fallback to system call */ 12119: lhi %r1,__NR_clock_gettime 122 svc 0 123 br %r14 124 12520: .long 1000000000 12621: .long _vdso_data - 0b 127 .cfi_endproc 128 .size __kernel_clock_gettime,.-__kernel_clock_gettime 129