1 |
1275 |
phoenix |
/*
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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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* 1999-01-16 Ulrich Windl
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20 |
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* Introduced error checking for many cases 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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* Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10)
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24 |
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* (Even though the technical memorandum forbids it)
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25 |
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*/
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26 |
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27 |
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#include <linux/mm.h>
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28 |
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#include <linux/timex.h>
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29 |
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#include <linux/smp_lock.h>
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30 |
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31 |
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#include <asm/uaccess.h>
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32 |
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33 |
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/*
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34 |
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* The timezone where the local system is located. Used as a default by some
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35 |
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* programs who obtain this value by using gettimeofday.
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36 |
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*/
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37 |
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struct timezone sys_tz;
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38 |
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39 |
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/* The xtime_lock is not only serializing the xtime read/writes but it's also
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40 |
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serializing all accesses to the global NTP variables now. */
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41 |
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extern rwlock_t xtime_lock;
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42 |
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43 |
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#if !defined(__alpha__) && !defined(__ia64__)
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44 |
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45 |
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/*
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46 |
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* sys_time() can be implemented in user-level using
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47 |
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* sys_gettimeofday(). Is this for backwards compatibility? If so,
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48 |
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* why not move it into the appropriate arch directory (for those
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49 |
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* architectures that need it).
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50 |
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*
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51 |
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* XXX This function is NOT 64-bit clean!
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52 |
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*/
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53 |
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asmlinkage long sys_time(int * tloc)
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54 |
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{
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55 |
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struct timeval now;
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56 |
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int i;
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57 |
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58 |
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do_gettimeofday(&now);
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59 |
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i = now.tv_sec;
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60 |
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if (tloc) {
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61 |
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if (put_user(i,tloc))
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62 |
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i = -EFAULT;
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63 |
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}
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64 |
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return i;
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65 |
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}
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66 |
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67 |
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/*
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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,
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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).
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72 |
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*/
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73 |
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74 |
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asmlinkage long sys_stime(int * tptr)
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75 |
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{
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76 |
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int value;
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77 |
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78 |
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if (!capable(CAP_SYS_TIME))
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79 |
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return -EPERM;
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80 |
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if (get_user(value, tptr))
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81 |
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return -EFAULT;
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82 |
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write_lock_irq(&xtime_lock);
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83 |
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vxtime_lock();
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84 |
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xtime.tv_sec = value;
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85 |
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xtime.tv_usec = 0;
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86 |
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vxtime_unlock();
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87 |
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time_adjust = 0; /* stop active adjtime() */
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88 |
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time_status |= STA_UNSYNC;
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89 |
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time_maxerror = NTP_PHASE_LIMIT;
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90 |
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time_esterror = NTP_PHASE_LIMIT;
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91 |
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write_unlock_irq(&xtime_lock);
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92 |
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return 0;
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93 |
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}
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94 |
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95 |
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#endif
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96 |
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97 |
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asmlinkage long sys_gettimeofday(struct timeval *tv, struct timezone *tz)
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98 |
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{
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99 |
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if (tv) {
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100 |
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struct timeval ktv;
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101 |
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do_gettimeofday(&ktv);
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102 |
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if (copy_to_user(tv, &ktv, sizeof(ktv)))
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103 |
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return -EFAULT;
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104 |
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}
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105 |
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if (tz) {
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106 |
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if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
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107 |
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return -EFAULT;
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108 |
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}
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109 |
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return 0;
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110 |
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}
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111 |
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|
112 |
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/*
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113 |
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* Adjust the time obtained from the CMOS to be UTC time instead of
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114 |
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* local time.
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115 |
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*
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116 |
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* This is ugly, but preferable to the alternatives. Otherwise we
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117 |
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* would either need to write a program to do it in /etc/rc (and risk
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118 |
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* confusion if the program gets run more than once; it would also be
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119 |
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* hard to make the program warp the clock precisely n hours) or
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120 |
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* compile in the timezone information into the kernel. Bad, bad....
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121 |
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*
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122 |
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* - TYT, 1992-01-01
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123 |
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*
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124 |
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* The best thing to do is to keep the CMOS clock in universal time (UTC)
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125 |
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* as real UNIX machines always do it. This avoids all headaches about
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126 |
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* daylight saving times and warping kernel clocks.
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127 |
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*/
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128 |
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inline static void warp_clock(void)
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129 |
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{
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130 |
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write_lock_irq(&xtime_lock);
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131 |
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vxtime_lock();
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132 |
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xtime.tv_sec += sys_tz.tz_minuteswest * 60;
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133 |
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vxtime_unlock();
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134 |
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write_unlock_irq(&xtime_lock);
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135 |
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}
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136 |
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137 |
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/*
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138 |
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* In case for some reason the CMOS clock has not already been running
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139 |
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* in UTC, but in some local time: The first time we set the timezone,
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140 |
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* we will warp the clock so that it is ticking UTC time instead of
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141 |
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* local time. Presumably, if someone is setting the timezone then we
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142 |
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* are running in an environment where the programs understand about
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143 |
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* timezones. This should be done at boot time in the /etc/rc script,
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144 |
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* as soon as possible, so that the clock can be set right. Otherwise,
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145 |
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* various programs will get confused when the clock gets warped.
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146 |
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*/
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147 |
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|
148 |
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int do_sys_settimeofday(struct timeval *tv, struct timezone *tz)
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149 |
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{
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150 |
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static int firsttime = 1;
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151 |
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152 |
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if (!capable(CAP_SYS_TIME))
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153 |
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return -EPERM;
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154 |
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155 |
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if (tz) {
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156 |
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/* SMP safe, global irq locking makes it work. */
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157 |
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sys_tz = *tz;
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158 |
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if (firsttime) {
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159 |
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firsttime = 0;
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160 |
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if (!tv)
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161 |
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warp_clock();
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162 |
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}
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163 |
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}
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164 |
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if (tv)
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165 |
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{
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166 |
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/* SMP safe, again the code in arch/foo/time.c should
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167 |
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* globally block out interrupts when it runs.
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168 |
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*/
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169 |
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do_settimeofday(tv);
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170 |
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}
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171 |
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return 0;
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172 |
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}
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173 |
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174 |
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asmlinkage long sys_settimeofday(struct timeval *tv, struct timezone *tz)
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175 |
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{
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176 |
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struct timeval new_tv;
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177 |
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struct timezone new_tz;
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178 |
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179 |
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if (tv) {
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180 |
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if (copy_from_user(&new_tv, tv, sizeof(*tv)))
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181 |
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return -EFAULT;
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182 |
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}
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183 |
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if (tz) {
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184 |
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if (copy_from_user(&new_tz, tz, sizeof(*tz)))
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185 |
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return -EFAULT;
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186 |
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}
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187 |
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188 |
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return do_sys_settimeofday(tv ? &new_tv : NULL, tz ? &new_tz : NULL);
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189 |
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}
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190 |
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|
191 |
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long pps_offset; /* pps time offset (us) */
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192 |
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long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */
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193 |
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|
194 |
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long pps_freq; /* frequency offset (scaled ppm) */
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195 |
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long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */
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196 |
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197 |
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long pps_valid = PPS_VALID; /* pps signal watchdog counter */
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198 |
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|
199 |
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int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */
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200 |
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|
201 |
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long pps_jitcnt; /* jitter limit exceeded */
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202 |
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long pps_calcnt; /* calibration intervals */
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203 |
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long pps_errcnt; /* calibration errors */
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204 |
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long pps_stbcnt; /* stability limit exceeded */
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205 |
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|
206 |
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/* hook for a loadable hardpps kernel module */
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207 |
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void (*hardpps_ptr)(struct timeval *);
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208 |
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|
209 |
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/* adjtimex mainly allows reading (and writing, if superuser) of
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210 |
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* kernel time-keeping variables. used by xntpd.
|
211 |
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*/
|
212 |
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int do_adjtimex(struct timex *txc)
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213 |
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{
|
214 |
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long ltemp, mtemp, save_adjust;
|
215 |
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int result;
|
216 |
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|
217 |
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/* In order to modify anything, you gotta be super-user! */
|
218 |
|
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if (txc->modes && !capable(CAP_SYS_TIME))
|
219 |
|
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return -EPERM;
|
220 |
|
|
|
221 |
|
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/* Now we validate the data before disabling interrupts */
|
222 |
|
|
|
223 |
|
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if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
|
224 |
|
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/* singleshot must not be used with any other mode bits */
|
225 |
|
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if (txc->modes != ADJ_OFFSET_SINGLESHOT)
|
226 |
|
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return -EINVAL;
|
227 |
|
|
|
228 |
|
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if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
|
229 |
|
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/* adjustment Offset limited to +- .512 seconds */
|
230 |
|
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if (txc->offset <= - MAXPHASE || txc->offset >= MAXPHASE )
|
231 |
|
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return -EINVAL;
|
232 |
|
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|
233 |
|
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/* if the quartz is off by more than 10% something is VERY wrong ! */
|
234 |
|
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if (txc->modes & ADJ_TICK)
|
235 |
|
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if (txc->tick < 900000/HZ || txc->tick > 1100000/HZ)
|
236 |
|
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return -EINVAL;
|
237 |
|
|
|
238 |
|
|
write_lock_irq(&xtime_lock);
|
239 |
|
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result = time_state; /* mostly `TIME_OK' */
|
240 |
|
|
|
241 |
|
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/* Save for later - semantics of adjtime is to return old value */
|
242 |
|
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save_adjust = time_adjust;
|
243 |
|
|
|
244 |
|
|
#if 0 /* STA_CLOCKERR is never set yet */
|
245 |
|
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time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */
|
246 |
|
|
#endif
|
247 |
|
|
/* If there are input parameters, then process them */
|
248 |
|
|
if (txc->modes)
|
249 |
|
|
{
|
250 |
|
|
if (txc->modes & ADJ_STATUS) /* only set allowed bits */
|
251 |
|
|
time_status = (txc->status & ~STA_RONLY) |
|
252 |
|
|
(time_status & STA_RONLY);
|
253 |
|
|
|
254 |
|
|
if (txc->modes & ADJ_FREQUENCY) { /* p. 22 */
|
255 |
|
|
if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) {
|
256 |
|
|
result = -EINVAL;
|
257 |
|
|
goto leave;
|
258 |
|
|
}
|
259 |
|
|
time_freq = txc->freq - pps_freq;
|
260 |
|
|
}
|
261 |
|
|
|
262 |
|
|
if (txc->modes & ADJ_MAXERROR) {
|
263 |
|
|
if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
|
264 |
|
|
result = -EINVAL;
|
265 |
|
|
goto leave;
|
266 |
|
|
}
|
267 |
|
|
time_maxerror = txc->maxerror;
|
268 |
|
|
}
|
269 |
|
|
|
270 |
|
|
if (txc->modes & ADJ_ESTERROR) {
|
271 |
|
|
if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
|
272 |
|
|
result = -EINVAL;
|
273 |
|
|
goto leave;
|
274 |
|
|
}
|
275 |
|
|
time_esterror = txc->esterror;
|
276 |
|
|
}
|
277 |
|
|
|
278 |
|
|
if (txc->modes & ADJ_TIMECONST) { /* p. 24 */
|
279 |
|
|
if (txc->constant < 0) { /* NTP v4 uses values > 6 */
|
280 |
|
|
result = -EINVAL;
|
281 |
|
|
goto leave;
|
282 |
|
|
}
|
283 |
|
|
time_constant = txc->constant;
|
284 |
|
|
}
|
285 |
|
|
|
286 |
|
|
if (txc->modes & ADJ_OFFSET) { /* values checked earlier */
|
287 |
|
|
if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
|
288 |
|
|
/* adjtime() is independent from ntp_adjtime() */
|
289 |
|
|
time_adjust = txc->offset;
|
290 |
|
|
}
|
291 |
|
|
else if ( time_status & (STA_PLL | STA_PPSTIME) ) {
|
292 |
|
|
ltemp = (time_status & (STA_PPSTIME | STA_PPSSIGNAL)) ==
|
293 |
|
|
(STA_PPSTIME | STA_PPSSIGNAL) ?
|
294 |
|
|
pps_offset : txc->offset;
|
295 |
|
|
|
296 |
|
|
/*
|
297 |
|
|
* Scale the phase adjustment and
|
298 |
|
|
* clamp to the operating range.
|
299 |
|
|
*/
|
300 |
|
|
if (ltemp > MAXPHASE)
|
301 |
|
|
time_offset = MAXPHASE << SHIFT_UPDATE;
|
302 |
|
|
else if (ltemp < -MAXPHASE)
|
303 |
|
|
time_offset = -(MAXPHASE << SHIFT_UPDATE);
|
304 |
|
|
else
|
305 |
|
|
time_offset = ltemp << SHIFT_UPDATE;
|
306 |
|
|
|
307 |
|
|
/*
|
308 |
|
|
* Select whether the frequency is to be controlled
|
309 |
|
|
* and in which mode (PLL or FLL). Clamp to the operating
|
310 |
|
|
* range. Ugly multiply/divide should be replaced someday.
|
311 |
|
|
*/
|
312 |
|
|
|
313 |
|
|
if (time_status & STA_FREQHOLD || time_reftime == 0)
|
314 |
|
|
time_reftime = xtime.tv_sec;
|
315 |
|
|
mtemp = xtime.tv_sec - time_reftime;
|
316 |
|
|
time_reftime = xtime.tv_sec;
|
317 |
|
|
if (time_status & STA_FLL) {
|
318 |
|
|
if (mtemp >= MINSEC) {
|
319 |
|
|
ltemp = (time_offset / mtemp) << (SHIFT_USEC -
|
320 |
|
|
SHIFT_UPDATE);
|
321 |
|
|
if (ltemp < 0)
|
322 |
|
|
time_freq -= -ltemp >> SHIFT_KH;
|
323 |
|
|
else
|
324 |
|
|
time_freq += ltemp >> SHIFT_KH;
|
325 |
|
|
} else /* calibration interval too short (p. 12) */
|
326 |
|
|
result = TIME_ERROR;
|
327 |
|
|
} else { /* PLL mode */
|
328 |
|
|
if (mtemp < MAXSEC) {
|
329 |
|
|
ltemp *= mtemp;
|
330 |
|
|
if (ltemp < 0)
|
331 |
|
|
time_freq -= -ltemp >> (time_constant +
|
332 |
|
|
time_constant +
|
333 |
|
|
SHIFT_KF - SHIFT_USEC);
|
334 |
|
|
else
|
335 |
|
|
time_freq += ltemp >> (time_constant +
|
336 |
|
|
time_constant +
|
337 |
|
|
SHIFT_KF - SHIFT_USEC);
|
338 |
|
|
} else /* calibration interval too long (p. 12) */
|
339 |
|
|
result = TIME_ERROR;
|
340 |
|
|
}
|
341 |
|
|
if (time_freq > time_tolerance)
|
342 |
|
|
time_freq = time_tolerance;
|
343 |
|
|
else if (time_freq < -time_tolerance)
|
344 |
|
|
time_freq = -time_tolerance;
|
345 |
|
|
} /* STA_PLL || STA_PPSTIME */
|
346 |
|
|
} /* txc->modes & ADJ_OFFSET */
|
347 |
|
|
if (txc->modes & ADJ_TICK) {
|
348 |
|
|
/* if the quartz is off by more than 10% something is
|
349 |
|
|
VERY wrong ! */
|
350 |
|
|
if (txc->tick < 900000/HZ || txc->tick > 1100000/HZ) {
|
351 |
|
|
result = -EINVAL;
|
352 |
|
|
goto leave;
|
353 |
|
|
}
|
354 |
|
|
tick = txc->tick;
|
355 |
|
|
}
|
356 |
|
|
} /* txc->modes */
|
357 |
|
|
leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0
|
358 |
|
|
|| ((time_status & (STA_PPSFREQ|STA_PPSTIME)) != 0
|
359 |
|
|
&& (time_status & STA_PPSSIGNAL) == 0)
|
360 |
|
|
/* p. 24, (b) */
|
361 |
|
|
|| ((time_status & (STA_PPSTIME|STA_PPSJITTER))
|
362 |
|
|
== (STA_PPSTIME|STA_PPSJITTER))
|
363 |
|
|
/* p. 24, (c) */
|
364 |
|
|
|| ((time_status & STA_PPSFREQ) != 0
|
365 |
|
|
&& (time_status & (STA_PPSWANDER|STA_PPSERROR)) != 0))
|
366 |
|
|
/* p. 24, (d) */
|
367 |
|
|
result = TIME_ERROR;
|
368 |
|
|
|
369 |
|
|
if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
|
370 |
|
|
txc->offset = save_adjust;
|
371 |
|
|
else {
|
372 |
|
|
if (time_offset < 0)
|
373 |
|
|
txc->offset = -(-time_offset >> SHIFT_UPDATE);
|
374 |
|
|
else
|
375 |
|
|
txc->offset = time_offset >> SHIFT_UPDATE;
|
376 |
|
|
}
|
377 |
|
|
txc->freq = time_freq + pps_freq;
|
378 |
|
|
txc->maxerror = time_maxerror;
|
379 |
|
|
txc->esterror = time_esterror;
|
380 |
|
|
txc->status = time_status;
|
381 |
|
|
txc->constant = time_constant;
|
382 |
|
|
txc->precision = time_precision;
|
383 |
|
|
txc->tolerance = time_tolerance;
|
384 |
|
|
txc->tick = tick;
|
385 |
|
|
txc->ppsfreq = pps_freq;
|
386 |
|
|
txc->jitter = pps_jitter >> PPS_AVG;
|
387 |
|
|
txc->shift = pps_shift;
|
388 |
|
|
txc->stabil = pps_stabil;
|
389 |
|
|
txc->jitcnt = pps_jitcnt;
|
390 |
|
|
txc->calcnt = pps_calcnt;
|
391 |
|
|
txc->errcnt = pps_errcnt;
|
392 |
|
|
txc->stbcnt = pps_stbcnt;
|
393 |
|
|
write_unlock_irq(&xtime_lock);
|
394 |
|
|
do_gettimeofday(&txc->time);
|
395 |
|
|
return(result);
|
396 |
|
|
}
|
397 |
|
|
|
398 |
|
|
asmlinkage long sys_adjtimex(struct timex *txc_p)
|
399 |
|
|
{
|
400 |
|
|
struct timex txc; /* Local copy of parameter */
|
401 |
|
|
int ret;
|
402 |
|
|
|
403 |
|
|
/* Copy the user data space into the kernel copy
|
404 |
|
|
* structure. But bear in mind that the structures
|
405 |
|
|
* may change
|
406 |
|
|
*/
|
407 |
|
|
if(copy_from_user(&txc, txc_p, sizeof(struct timex)))
|
408 |
|
|
return -EFAULT;
|
409 |
|
|
ret = do_adjtimex(&txc);
|
410 |
|
|
return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
|
411 |
|
|
}
|