| 1 |
1634 |
jcastillo |
/*
|
| 2 |
|
|
* linux/kernel/time.c
|
| 3 |
|
|
*
|
| 4 |
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
| 5 |
|
|
*
|
| 6 |
|
|
* This file contains the interface functions for the various
|
| 7 |
|
|
* time related system calls: time, stime, gettimeofday, settimeofday,
|
| 8 |
|
|
* adjtime
|
| 9 |
|
|
*/
|
| 10 |
|
|
/*
|
| 11 |
|
|
* Modification history kernel/time.c
|
| 12 |
|
|
*
|
| 13 |
|
|
* 1993-09-02 Philip Gladstone
|
| 14 |
|
|
* Created file with time related functions from sched.c and adjtimex()
|
| 15 |
|
|
* 1993-10-08 Torsten Duwe
|
| 16 |
|
|
* adjtime interface update and CMOS clock write code
|
| 17 |
|
|
* 1995-08-13 Torsten Duwe
|
| 18 |
|
|
* kernel PLL updated to 1994-12-13 specs (rfc-1589)
|
| 19 |
|
|
* 1996-10-22, 1997-09-13 Ulrich Windl
|
| 20 |
|
|
* support for external PPS signal, error checking in adjtimex()
|
| 21 |
|
|
* Updated NTP code according to technical memorandum Jan '96
|
| 22 |
|
|
* "A Kernel Model for Precision Timekeeping" by Dave Mills
|
| 23 |
|
|
* 1998-03-05 Ulrich Windl
|
| 24 |
|
|
* Allow time_constant larger than MAXTC(6) for NTP v4
|
| 25 |
|
|
* (debated with and blessed by Dave Mills, despite of earlier work
|
| 26 |
|
|
* and words)
|
| 27 |
|
|
*/
|
| 28 |
|
|
|
| 29 |
|
|
#include <linux/errno.h>
|
| 30 |
|
|
#include <linux/sched.h>
|
| 31 |
|
|
#include <linux/kernel.h>
|
| 32 |
|
|
#include <linux/param.h>
|
| 33 |
|
|
#include <linux/string.h>
|
| 34 |
|
|
#include <linux/mm.h>
|
| 35 |
|
|
#include <linux/timex.h>
|
| 36 |
|
|
|
| 37 |
|
|
#include <asm/segment.h>
|
| 38 |
|
|
|
| 39 |
|
|
/*
|
| 40 |
|
|
* The timezone where the local system is located. Used as a default by some
|
| 41 |
|
|
* programs who obtain this value by using gettimeofday.
|
| 42 |
|
|
*/
|
| 43 |
|
|
struct timezone sys_tz = { 0, 0};
|
| 44 |
|
|
|
| 45 |
|
|
#ifndef __alpha__
|
| 46 |
|
|
|
| 47 |
|
|
/*
|
| 48 |
|
|
* sys_time() can be implemented in user-level using
|
| 49 |
|
|
* sys_gettimeofday(). Is this for backwards compatibility? If so,
|
| 50 |
|
|
* why not move it into the appropriate arch directory (for those
|
| 51 |
|
|
* architectures that need it).
|
| 52 |
|
|
*/
|
| 53 |
|
|
asmlinkage int sys_time(int * tloc)
|
| 54 |
|
|
{
|
| 55 |
|
|
int i;
|
| 56 |
|
|
|
| 57 |
|
|
i = CURRENT_TIME;
|
| 58 |
|
|
if (tloc) {
|
| 59 |
|
|
int error = verify_area(VERIFY_WRITE, tloc, sizeof(*tloc));
|
| 60 |
|
|
if (error)
|
| 61 |
|
|
return error;
|
| 62 |
|
|
put_user(i,tloc);
|
| 63 |
|
|
}
|
| 64 |
|
|
return i;
|
| 65 |
|
|
}
|
| 66 |
|
|
|
| 67 |
|
|
/*
|
| 68 |
|
|
* sys_stime() can be implemented in user-level using
|
| 69 |
|
|
* sys_settimeofday(). Is this for backwards compatibility? If so,
|
| 70 |
|
|
* why not move it into the appropriate arch directory (for those
|
| 71 |
|
|
* architectures that need it).
|
| 72 |
|
|
*/
|
| 73 |
|
|
asmlinkage int sys_stime(int * tptr)
|
| 74 |
|
|
{
|
| 75 |
|
|
int error, value;
|
| 76 |
|
|
|
| 77 |
|
|
if (!suser())
|
| 78 |
|
|
return -EPERM;
|
| 79 |
|
|
error = verify_area(VERIFY_READ, tptr, sizeof(*tptr));
|
| 80 |
|
|
if (error)
|
| 81 |
|
|
return error;
|
| 82 |
|
|
value = get_user(tptr);
|
| 83 |
|
|
cli();
|
| 84 |
|
|
xtime.tv_sec = value;
|
| 85 |
|
|
xtime.tv_usec = 0;
|
| 86 |
|
|
time_adjust = 0; /* stop active adjtime() */
|
| 87 |
|
|
time_status |= STA_UNSYNC;
|
| 88 |
|
|
time_state = TIME_ERROR; /* p. 24, (a) */
|
| 89 |
|
|
time_maxerror = NTP_PHASE_LIMIT;
|
| 90 |
|
|
time_esterror = NTP_PHASE_LIMIT;
|
| 91 |
|
|
sti();
|
| 92 |
|
|
return 0;
|
| 93 |
|
|
}
|
| 94 |
|
|
|
| 95 |
|
|
#endif
|
| 96 |
|
|
|
| 97 |
|
|
asmlinkage int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
|
| 98 |
|
|
{
|
| 99 |
|
|
int error;
|
| 100 |
|
|
|
| 101 |
|
|
if (tv) {
|
| 102 |
|
|
struct timeval ktv;
|
| 103 |
|
|
error = verify_area(VERIFY_WRITE, tv, sizeof *tv);
|
| 104 |
|
|
if (error)
|
| 105 |
|
|
return error;
|
| 106 |
|
|
do_gettimeofday(&ktv);
|
| 107 |
|
|
memcpy_tofs(tv, &ktv, sizeof(ktv));
|
| 108 |
|
|
}
|
| 109 |
|
|
if (tz) {
|
| 110 |
|
|
error = verify_area(VERIFY_WRITE, tz, sizeof *tz);
|
| 111 |
|
|
if (error)
|
| 112 |
|
|
return error;
|
| 113 |
|
|
memcpy_tofs(tz, &sys_tz, sizeof(sys_tz));
|
| 114 |
|
|
}
|
| 115 |
|
|
return 0;
|
| 116 |
|
|
}
|
| 117 |
|
|
|
| 118 |
|
|
/*
|
| 119 |
|
|
* Adjust the time obtained from the CMOS to be UTC time instead of
|
| 120 |
|
|
* local time.
|
| 121 |
|
|
*
|
| 122 |
|
|
* This is ugly, but preferable to the alternatives. Otherwise we
|
| 123 |
|
|
* would either need to write a program to do it in /etc/rc (and risk
|
| 124 |
|
|
* confusion if the program gets run more than once; it would also be
|
| 125 |
|
|
* hard to make the program warp the clock precisely n hours) or
|
| 126 |
|
|
* compile in the timezone information into the kernel. Bad, bad....
|
| 127 |
|
|
*
|
| 128 |
|
|
* - TYT, 1992-01-01
|
| 129 |
|
|
*
|
| 130 |
|
|
* The best thing to do is to keep the CMOS clock in universal time (UTC)
|
| 131 |
|
|
* as real UNIX machines always do it. This avoids all headaches about
|
| 132 |
|
|
* daylight saving times and warping kernel clocks.
|
| 133 |
|
|
*/
|
| 134 |
|
|
inline static void warp_clock(void)
|
| 135 |
|
|
{
|
| 136 |
|
|
cli();
|
| 137 |
|
|
xtime.tv_sec += sys_tz.tz_minuteswest * 60;
|
| 138 |
|
|
sti();
|
| 139 |
|
|
}
|
| 140 |
|
|
|
| 141 |
|
|
/*
|
| 142 |
|
|
* In case for some reason the CMOS clock has not already been running
|
| 143 |
|
|
* in UTC, but in some local time: The first time we set the timezone,
|
| 144 |
|
|
* we will warp the clock so that it is ticking UTC time instead of
|
| 145 |
|
|
* local time. Presumably, if someone is setting the timezone then we
|
| 146 |
|
|
* are running in an environment where the programs understand about
|
| 147 |
|
|
* timezones. This should be done at boot time in the /etc/rc script,
|
| 148 |
|
|
* as soon as possible, so that the clock can be set right. Otherwise,
|
| 149 |
|
|
* various programs will get confused when the clock gets warped.
|
| 150 |
|
|
*/
|
| 151 |
|
|
asmlinkage int sys_settimeofday(struct timeval *tv, struct timezone *tz)
|
| 152 |
|
|
{
|
| 153 |
|
|
static int firsttime = 1;
|
| 154 |
|
|
struct timeval new_tv;
|
| 155 |
|
|
struct timezone new_tz;
|
| 156 |
|
|
|
| 157 |
|
|
if (!suser())
|
| 158 |
|
|
return -EPERM;
|
| 159 |
|
|
if (tv) {
|
| 160 |
|
|
int error = verify_area(VERIFY_READ, tv, sizeof(*tv));
|
| 161 |
|
|
if (error)
|
| 162 |
|
|
return error;
|
| 163 |
|
|
memcpy_fromfs(&new_tv, tv, sizeof(*tv));
|
| 164 |
|
|
}
|
| 165 |
|
|
if (tz) {
|
| 166 |
|
|
int error = verify_area(VERIFY_READ, tz, sizeof(*tz));
|
| 167 |
|
|
if (error)
|
| 168 |
|
|
return error;
|
| 169 |
|
|
memcpy_fromfs(&new_tz, tz, sizeof(*tz));
|
| 170 |
|
|
}
|
| 171 |
|
|
if (tz) {
|
| 172 |
|
|
sys_tz = new_tz;
|
| 173 |
|
|
if (firsttime) {
|
| 174 |
|
|
firsttime = 0;
|
| 175 |
|
|
if (!tv)
|
| 176 |
|
|
warp_clock();
|
| 177 |
|
|
}
|
| 178 |
|
|
}
|
| 179 |
|
|
if (tv)
|
| 180 |
|
|
do_settimeofday(&new_tv);
|
| 181 |
|
|
return 0;
|
| 182 |
|
|
}
|
| 183 |
|
|
|
| 184 |
|
|
long pps_offset = 0; /* pps time offset (us) */
|
| 185 |
|
|
long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */
|
| 186 |
|
|
|
| 187 |
|
|
long pps_freq = 0; /* frequency offset (scaled ppm) */
|
| 188 |
|
|
long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */
|
| 189 |
|
|
|
| 190 |
|
|
long pps_valid = PPS_VALID; /* pps signal watchdog counter */
|
| 191 |
|
|
|
| 192 |
|
|
int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */
|
| 193 |
|
|
|
| 194 |
|
|
long pps_jitcnt = 0; /* jitter limit exceeded */
|
| 195 |
|
|
long pps_calcnt = 0; /* calibration intervals */
|
| 196 |
|
|
long pps_errcnt = 0; /* calibration errors */
|
| 197 |
|
|
long pps_stbcnt = 0; /* stability limit exceeded */
|
| 198 |
|
|
|
| 199 |
|
|
/* hook for a loadable hardpps kernel module */
|
| 200 |
|
|
void (*hardpps_ptr)(struct timeval *) = (void (*)(struct timeval *))0;
|
| 201 |
|
|
|
| 202 |
|
|
/* adjtimex mainly allows reading (and writing, if superuser) of
|
| 203 |
|
|
* kernel time-keeping variables. used by xntpd.
|
| 204 |
|
|
*/
|
| 205 |
|
|
asmlinkage int sys_adjtimex(struct timex *txc_p)
|
| 206 |
|
|
{
|
| 207 |
|
|
long ltemp, mtemp, save_adjust;
|
| 208 |
|
|
int error = 0;
|
| 209 |
|
|
|
| 210 |
|
|
/* Local copy of parameter */
|
| 211 |
|
|
struct timex txc;
|
| 212 |
|
|
|
| 213 |
|
|
error = verify_area(VERIFY_WRITE, txc_p, sizeof(struct timex));
|
| 214 |
|
|
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 |
|
|
*/
|
| 221 |
|
|
memcpy_fromfs(&txc, txc_p, sizeof(struct timex));
|
| 222 |
|
|
|
| 223 |
|
|
/* 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 |
|
|
*/
|
| 229 |
|
|
if (txc.modes != ADJ_OFFSET_SINGLESHOT && (txc.modes & ADJ_OFFSET))
|
| 230 |
|
|
/* adjustment Offset limited to +- .512 seconds */
|
| 231 |
|
|
if (txc.offset <= - MAXPHASE || txc.offset >= MAXPHASE )
|
| 232 |
|
|
return -EINVAL;
|
| 233 |
|
|
|
| 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 |
|
|
}
|
