| 1 |
199 |
simons |
/*
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| 2 |
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* linux/kernel/time.c
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| 3 |
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*
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| 4 |
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* Copyright (C) 1991, 1992 Linus Torvalds
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| 5 |
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*
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| 6 |
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* This file contains the interface functions for the various
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| 7 |
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* time related system calls: time, stime, gettimeofday, settimeofday,
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| 8 |
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* adjtime
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| 9 |
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*/
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| 10 |
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/*
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| 11 |
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* Modification history kernel/time.c
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| 12 |
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*
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| 13 |
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* 1993-09-02 Philip Gladstone
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| 14 |
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* Created file with time related functions from sched.c and adjtimex()
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| 15 |
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* 1993-10-08 Torsten Duwe
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| 16 |
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* adjtime interface update and CMOS clock write code
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| 17 |
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* 1995-08-13 Torsten Duwe
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| 18 |
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* kernel PLL updated to 1994-12-13 specs (rfc-1589)
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| 19 |
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* 1996-10-22, 1997-09-13 Ulrich Windl
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| 20 |
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* support for external PPS signal, error checking in adjtimex()
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| 21 |
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* Updated NTP code according to technical memorandum Jan '96
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| 22 |
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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| 23 |
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* 1998-03-05 Ulrich Windl
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| 24 |
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* Allow time_constant larger than MAXTC(6) for NTP v4
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| 25 |
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* (debated with and blessed by Dave Mills, despite of earlier work
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| 26 |
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* and words)
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| 27 |
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*/
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| 28 |
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| 29 |
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#include <linux/errno.h>
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| 30 |
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#include <linux/sched.h>
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| 31 |
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#include <linux/kernel.h>
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| 32 |
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#include <linux/param.h>
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| 33 |
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#include <linux/string.h>
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| 34 |
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#include <linux/mm.h>
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| 35 |
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#include <linux/timex.h>
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| 36 |
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| 37 |
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#include <asm/segment.h>
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| 38 |
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| 39 |
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/*
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| 40 |
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* The timezone where the local system is located. Used as a default by some
|
| 41 |
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* programs who obtain this value by using gettimeofday.
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| 42 |
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*/
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| 43 |
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struct timezone sys_tz = { 0, 0};
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| 44 |
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| 45 |
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#ifndef __alpha__
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| 46 |
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| 47 |
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/*
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| 48 |
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* sys_time() can be implemented in user-level using
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| 49 |
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* sys_gettimeofday(). Is this for backwards compatibility? If so,
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| 50 |
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* why not move it into the appropriate arch directory (for those
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| 51 |
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* architectures that need it).
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| 52 |
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*/
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| 53 |
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asmlinkage int sys_time(int * tloc)
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| 54 |
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{
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| 55 |
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int i;
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| 56 |
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| 57 |
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i = CURRENT_TIME;
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| 58 |
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if (tloc) {
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| 59 |
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int error = verify_area(VERIFY_WRITE, tloc, sizeof(*tloc));
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| 60 |
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if (error)
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| 61 |
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return error;
|
| 62 |
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put_user(i,tloc);
|
| 63 |
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}
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| 64 |
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return i;
|
| 65 |
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}
|
| 66 |
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| 67 |
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/*
|
| 68 |
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* sys_stime() can be implemented in user-level using
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| 69 |
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* sys_settimeofday(). Is this for backwards compatibility? If so,
|
| 70 |
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* why not move it into the appropriate arch directory (for those
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| 71 |
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* architectures that need it).
|
| 72 |
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*/
|
| 73 |
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asmlinkage int sys_stime(int * tptr)
|
| 74 |
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{
|
| 75 |
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int error, value;
|
| 76 |
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|
| 77 |
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if (!suser())
|
| 78 |
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return -EPERM;
|
| 79 |
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error = verify_area(VERIFY_READ, tptr, sizeof(*tptr));
|
| 80 |
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if (error)
|
| 81 |
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return error;
|
| 82 |
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value = get_user(tptr);
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| 83 |
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cli();
|
| 84 |
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xtime.tv_sec = value;
|
| 85 |
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xtime.tv_usec = 0;
|
| 86 |
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time_adjust = 0; /* stop active adjtime() */
|
| 87 |
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time_status |= STA_UNSYNC;
|
| 88 |
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time_state = TIME_ERROR; /* p. 24, (a) */
|
| 89 |
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time_maxerror = NTP_PHASE_LIMIT;
|
| 90 |
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time_esterror = NTP_PHASE_LIMIT;
|
| 91 |
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sti();
|
| 92 |
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return 0;
|
| 93 |
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}
|
| 94 |
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| 95 |
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#endif
|
| 96 |
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|
| 97 |
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asmlinkage int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
|
| 98 |
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{
|
| 99 |
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int error;
|
| 100 |
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|
| 101 |
|
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if (tv) {
|
| 102 |
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struct timeval ktv;
|
| 103 |
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error = verify_area(VERIFY_WRITE, tv, sizeof *tv);
|
| 104 |
|
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if (error)
|
| 105 |
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return error;
|
| 106 |
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do_gettimeofday(&ktv);
|
| 107 |
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memcpy_tofs(tv, &ktv, sizeof(ktv));
|
| 108 |
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}
|
| 109 |
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if (tz) {
|
| 110 |
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error = verify_area(VERIFY_WRITE, tz, sizeof *tz);
|
| 111 |
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if (error)
|
| 112 |
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return error;
|
| 113 |
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memcpy_tofs(tz, &sys_tz, sizeof(sys_tz));
|
| 114 |
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}
|
| 115 |
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return 0;
|
| 116 |
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}
|
| 117 |
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|
| 118 |
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/*
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| 119 |
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* Adjust the time obtained from the CMOS to be UTC time instead of
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| 120 |
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* local time.
|
| 121 |
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*
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| 122 |
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* This is ugly, but preferable to the alternatives. Otherwise we
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| 123 |
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* would either need to write a program to do it in /etc/rc (and risk
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| 124 |
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* confusion if the program gets run more than once; it would also be
|
| 125 |
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* hard to make the program warp the clock precisely n hours) or
|
| 126 |
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* compile in the timezone information into the kernel. Bad, bad....
|
| 127 |
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*
|
| 128 |
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* - TYT, 1992-01-01
|
| 129 |
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*
|
| 130 |
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* The best thing to do is to keep the CMOS clock in universal time (UTC)
|
| 131 |
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* as real UNIX machines always do it. This avoids all headaches about
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| 132 |
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* daylight saving times and warping kernel clocks.
|
| 133 |
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*/
|
| 134 |
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inline static void warp_clock(void)
|
| 135 |
|
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{
|
| 136 |
|
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cli();
|
| 137 |
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xtime.tv_sec += sys_tz.tz_minuteswest * 60;
|
| 138 |
|
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sti();
|
| 139 |
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}
|
| 140 |
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|
| 141 |
|
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/*
|
| 142 |
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* In case for some reason the CMOS clock has not already been running
|
| 143 |
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* in UTC, but in some local time: The first time we set the timezone,
|
| 144 |
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* we will warp the clock so that it is ticking UTC time instead of
|
| 145 |
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* local time. Presumably, if someone is setting the timezone then we
|
| 146 |
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* are running in an environment where the programs understand about
|
| 147 |
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* timezones. This should be done at boot time in the /etc/rc script,
|
| 148 |
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* as soon as possible, so that the clock can be set right. Otherwise,
|
| 149 |
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* various programs will get confused when the clock gets warped.
|
| 150 |
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*/
|
| 151 |
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asmlinkage int sys_settimeofday(struct timeval *tv, struct timezone *tz)
|
| 152 |
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{
|
| 153 |
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static int firsttime = 1;
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| 154 |
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struct timeval new_tv;
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| 155 |
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struct timezone new_tz;
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| 156 |
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| 157 |
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if (!suser())
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| 158 |
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return -EPERM;
|
| 159 |
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if (tv) {
|
| 160 |
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int error = verify_area(VERIFY_READ, tv, sizeof(*tv));
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| 161 |
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if (error)
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| 162 |
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return error;
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| 163 |
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memcpy_fromfs(&new_tv, tv, sizeof(*tv));
|
| 164 |
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}
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| 165 |
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if (tz) {
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| 166 |
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int error = verify_area(VERIFY_READ, tz, sizeof(*tz));
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| 167 |
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if (error)
|
| 168 |
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return error;
|
| 169 |
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memcpy_fromfs(&new_tz, tz, sizeof(*tz));
|
| 170 |
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}
|
| 171 |
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if (tz) {
|
| 172 |
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sys_tz = new_tz;
|
| 173 |
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if (firsttime) {
|
| 174 |
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firsttime = 0;
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| 175 |
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if (!tv)
|
| 176 |
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warp_clock();
|
| 177 |
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}
|
| 178 |
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}
|
| 179 |
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if (tv)
|
| 180 |
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do_settimeofday(&new_tv);
|
| 181 |
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return 0;
|
| 182 |
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}
|
| 183 |
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|
| 184 |
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long pps_offset = 0; /* pps time offset (us) */
|
| 185 |
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long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */
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| 186 |
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| 187 |
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long pps_freq = 0; /* frequency offset (scaled ppm) */
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| 188 |
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long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */
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| 189 |
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|
| 190 |
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long pps_valid = PPS_VALID; /* pps signal watchdog counter */
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| 191 |
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| 192 |
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int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */
|
| 193 |
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|
| 194 |
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long pps_jitcnt = 0; /* jitter limit exceeded */
|
| 195 |
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long pps_calcnt = 0; /* calibration intervals */
|
| 196 |
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long pps_errcnt = 0; /* calibration errors */
|
| 197 |
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long pps_stbcnt = 0; /* stability limit exceeded */
|
| 198 |
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|
| 199 |
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/* hook for a loadable hardpps kernel module */
|
| 200 |
|
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void (*hardpps_ptr)(struct timeval *) = (void (*)(struct timeval *))0;
|
| 201 |
|
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|
| 202 |
|
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/* adjtimex mainly allows reading (and writing, if superuser) of
|
| 203 |
|
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* kernel time-keeping variables. used by xntpd.
|
| 204 |
|
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*/
|
| 205 |
|
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asmlinkage int sys_adjtimex(struct timex *txc_p)
|
| 206 |
|
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{
|
| 207 |
|
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long ltemp, mtemp, save_adjust;
|
| 208 |
|
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int error = 0;
|
| 209 |
|
|
|
| 210 |
|
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/* Local copy of parameter */
|
| 211 |
|
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struct timex txc;
|
| 212 |
|
|
|
| 213 |
|
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error = verify_area(VERIFY_WRITE, txc_p, sizeof(struct timex));
|
| 214 |
|
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if (error)
|
| 215 |
|
|
return error; /* do not write results */
|
| 216 |
|
|
|
| 217 |
|
|
/* Copy the user data space into the kernel copy
|
| 218 |
|
|
* structure. But bear in mind that the structures
|
| 219 |
|
|
* may change
|
| 220 |
|
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*/
|
| 221 |
|
|
memcpy_fromfs(&txc, txc_p, sizeof(struct timex));
|
| 222 |
|
|
|
| 223 |
|
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/* In order to modify anything, you gotta be super-user! */
|
| 224 |
|
|
if (txc.modes && !suser())
|
| 225 |
|
|
return -EPERM;
|
| 226 |
|
|
|
| 227 |
|
|
/* Now we validate the data before disabling interrupts
|
| 228 |
|
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*/
|
| 229 |
|
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if (txc.modes != ADJ_OFFSET_SINGLESHOT && (txc.modes & ADJ_OFFSET))
|
| 230 |
|
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/* adjustment Offset limited to +- .512 seconds */
|
| 231 |
|
|
if (txc.offset <= - MAXPHASE || txc.offset >= MAXPHASE )
|
| 232 |
|
|
return -EINVAL;
|
| 233 |
|
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|
| 234 |
|
|
cli();
|
| 235 |
|
|
|
| 236 |
|
|
/* Save for later - semantics of adjtime() is to return old value */
|
| 237 |
|
|
save_adjust = time_adjust;
|
| 238 |
|
|
|
| 239 |
|
|
/* If there are input parameters, then process them */
|
| 240 |
|
|
#if 0 /* STA_CLOCKERR is never set yet */
|
| 241 |
|
|
time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */
|
| 242 |
|
|
#endif
|
| 243 |
|
|
if (txc.modes)
|
| 244 |
|
|
{
|
| 245 |
|
|
if (time_state == TIME_ERROR)
|
| 246 |
|
|
time_state = TIME_OK; /* reset error -- why? */
|
| 247 |
|
|
|
| 248 |
|
|
if (txc.modes & ADJ_STATUS) /* only set allowed bits */
|
| 249 |
|
|
time_status = (txc.status & ~STA_RONLY) |
|
| 250 |
|
|
(time_status & STA_RONLY);
|
| 251 |
|
|
|
| 252 |
|
|
if (txc.modes & ADJ_FREQUENCY) { /* p. 22 */
|
| 253 |
|
|
if (txc.freq > MAXFREQ || txc.freq < -MAXFREQ) {
|
| 254 |
|
|
error = -EINVAL;
|
| 255 |
|
|
goto leave;
|
| 256 |
|
|
}
|
| 257 |
|
|
time_freq = txc.freq - pps_freq;
|
| 258 |
|
|
}
|
| 259 |
|
|
|
| 260 |
|
|
if (txc.modes & ADJ_MAXERROR) {
|
| 261 |
|
|
if (txc.maxerror < 0 || txc.maxerror >= NTP_PHASE_LIMIT) {
|
| 262 |
|
|
error = -EINVAL;
|
| 263 |
|
|
goto leave;
|
| 264 |
|
|
}
|
| 265 |
|
|
time_maxerror = txc.maxerror;
|
| 266 |
|
|
}
|
| 267 |
|
|
|
| 268 |
|
|
if (txc.modes & ADJ_ESTERROR) {
|
| 269 |
|
|
if (txc.esterror < 0 || txc.esterror >= NTP_PHASE_LIMIT) {
|
| 270 |
|
|
error = -EINVAL;
|
| 271 |
|
|
goto leave;
|
| 272 |
|
|
}
|
| 273 |
|
|
time_esterror = txc.esterror;
|
| 274 |
|
|
}
|
| 275 |
|
|
|
| 276 |
|
|
if (txc.modes & ADJ_TIMECONST) { /* p. 24 */
|
| 277 |
|
|
if (txc.constant < 0) { /* NTP v4 uses values > 6 */
|
| 278 |
|
|
error = -EINVAL;
|
| 279 |
|
|
goto leave;
|
| 280 |
|
|
}
|
| 281 |
|
|
time_constant = txc.constant;
|
| 282 |
|
|
}
|
| 283 |
|
|
|
| 284 |
|
|
if (txc.modes & ADJ_OFFSET) { /* values checked earlier */
|
| 285 |
|
|
if (txc.modes == ADJ_OFFSET_SINGLESHOT) {
|
| 286 |
|
|
/* adjtime() is independent from ntp_adjtime() */
|
| 287 |
|
|
time_adjust = txc.offset;
|
| 288 |
|
|
}
|
| 289 |
|
|
else if ( time_status & (STA_PLL | STA_PPSTIME) ) {
|
| 290 |
|
|
ltemp = (time_status & (STA_PPSTIME | STA_PPSSIGNAL)) ==
|
| 291 |
|
|
(STA_PPSTIME | STA_PPSSIGNAL) ?
|
| 292 |
|
|
pps_offset : txc.offset;
|
| 293 |
|
|
|
| 294 |
|
|
/*
|
| 295 |
|
|
* Scale the phase adjustment and
|
| 296 |
|
|
* clamp to the operating range.
|
| 297 |
|
|
*/
|
| 298 |
|
|
if (ltemp > MAXPHASE)
|
| 299 |
|
|
time_offset = MAXPHASE << SHIFT_UPDATE;
|
| 300 |
|
|
else if (ltemp < -MAXPHASE)
|
| 301 |
|
|
time_offset = -(MAXPHASE << SHIFT_UPDATE);
|
| 302 |
|
|
else
|
| 303 |
|
|
time_offset = ltemp << SHIFT_UPDATE;
|
| 304 |
|
|
|
| 305 |
|
|
/*
|
| 306 |
|
|
* Select whether the frequency is to be controlled
|
| 307 |
|
|
* and in which mode (PLL or FLL). Clamp to the operating
|
| 308 |
|
|
* range. Ugly multiply/divide should be replaced someday.
|
| 309 |
|
|
*/
|
| 310 |
|
|
|
| 311 |
|
|
if (time_status & STA_FREQHOLD || time_reftime == 0)
|
| 312 |
|
|
time_reftime = xtime.tv_sec;
|
| 313 |
|
|
mtemp = xtime.tv_sec - time_reftime;
|
| 314 |
|
|
time_reftime = xtime.tv_sec;
|
| 315 |
|
|
if (time_status & STA_FLL) {
|
| 316 |
|
|
if (mtemp >= MINSEC) {
|
| 317 |
|
|
ltemp = (time_offset / mtemp) << (SHIFT_USEC -
|
| 318 |
|
|
SHIFT_UPDATE);
|
| 319 |
|
|
if (ltemp < 0)
|
| 320 |
|
|
time_freq -= -ltemp >> SHIFT_KH;
|
| 321 |
|
|
else
|
| 322 |
|
|
time_freq += ltemp >> SHIFT_KH;
|
| 323 |
|
|
} else /* calibration interval too short (p. 12) */
|
| 324 |
|
|
time_state = TIME_ERROR;
|
| 325 |
|
|
} else { /* PLL mode */
|
| 326 |
|
|
if (mtemp < MAXSEC) {
|
| 327 |
|
|
ltemp *= mtemp;
|
| 328 |
|
|
if (ltemp < 0)
|
| 329 |
|
|
time_freq -= -ltemp >> (time_constant +
|
| 330 |
|
|
time_constant +
|
| 331 |
|
|
SHIFT_KF - SHIFT_USEC);
|
| 332 |
|
|
else
|
| 333 |
|
|
time_freq += ltemp >> (time_constant +
|
| 334 |
|
|
time_constant +
|
| 335 |
|
|
SHIFT_KF - SHIFT_USEC);
|
| 336 |
|
|
} else /* calibration interval too long (p. 12) */
|
| 337 |
|
|
time_state = TIME_ERROR;
|
| 338 |
|
|
}
|
| 339 |
|
|
if (time_freq > time_tolerance)
|
| 340 |
|
|
time_freq = time_tolerance;
|
| 341 |
|
|
else if (time_freq < -time_tolerance)
|
| 342 |
|
|
time_freq = -time_tolerance;
|
| 343 |
|
|
} /* STA_PLL || STA_PPSTIME */
|
| 344 |
|
|
} /* txc.modes & ADJ_OFFSET */
|
| 345 |
|
|
if (txc.modes & ADJ_TICK) {
|
| 346 |
|
|
/* if the quartz is off by more than 10% something is
|
| 347 |
|
|
VERY wrong ! */
|
| 348 |
|
|
if (txc.tick < 900000/HZ || txc.tick > 1100000/HZ) {
|
| 349 |
|
|
error = -EINVAL;
|
| 350 |
|
|
goto leave;
|
| 351 |
|
|
}
|
| 352 |
|
|
tick = txc.tick;
|
| 353 |
|
|
}
|
| 354 |
|
|
} /* txc.modes */
|
| 355 |
|
|
leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0
|
| 356 |
|
|
|| ((time_status & (STA_PPSFREQ|STA_PPSTIME)) != 0
|
| 357 |
|
|
&& (time_status & STA_PPSSIGNAL) == 0)
|
| 358 |
|
|
/* p. 24, (b) */
|
| 359 |
|
|
|| ((time_status & (STA_PPSTIME|STA_PPSJITTER))
|
| 360 |
|
|
== (STA_PPSTIME|STA_PPSJITTER))
|
| 361 |
|
|
/* p. 24, (c) */
|
| 362 |
|
|
|| ((time_status & STA_PPSFREQ) != 0
|
| 363 |
|
|
&& (time_status & (STA_PPSWANDER|STA_PPSERROR)) != 0))
|
| 364 |
|
|
/* p. 24, (d) */
|
| 365 |
|
|
time_state = TIME_ERROR;
|
| 366 |
|
|
|
| 367 |
|
|
if ((txc.modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
|
| 368 |
|
|
txc.offset = save_adjust;
|
| 369 |
|
|
else {
|
| 370 |
|
|
if (time_offset < 0)
|
| 371 |
|
|
txc.offset = -(-time_offset >> SHIFT_UPDATE);
|
| 372 |
|
|
else
|
| 373 |
|
|
txc.offset = time_offset >> SHIFT_UPDATE;
|
| 374 |
|
|
}
|
| 375 |
|
|
txc.freq = time_freq + pps_freq;
|
| 376 |
|
|
txc.maxerror = time_maxerror;
|
| 377 |
|
|
txc.esterror = time_esterror;
|
| 378 |
|
|
txc.status = time_status;
|
| 379 |
|
|
txc.constant = time_constant;
|
| 380 |
|
|
txc.precision = time_precision;
|
| 381 |
|
|
txc.tolerance = time_tolerance;
|
| 382 |
|
|
do_gettimeofday(&txc.time);
|
| 383 |
|
|
txc.tick = tick;
|
| 384 |
|
|
txc.ppsfreq = pps_freq;
|
| 385 |
|
|
txc.jitter = pps_jitter >> PPS_AVG;
|
| 386 |
|
|
txc.shift = pps_shift;
|
| 387 |
|
|
txc.stabil = pps_stabil;
|
| 388 |
|
|
txc.jitcnt = pps_jitcnt;
|
| 389 |
|
|
txc.calcnt = pps_calcnt;
|
| 390 |
|
|
txc.errcnt = pps_errcnt;
|
| 391 |
|
|
txc.stbcnt = pps_stbcnt;
|
| 392 |
|
|
|
| 393 |
|
|
sti();
|
| 394 |
|
|
|
| 395 |
|
|
memcpy_tofs(txc_p, &txc, sizeof(struct timex));
|
| 396 |
|
|
return(error < 0 ? error : time_state);
|
| 397 |
|
|
}
|
