1 /* 2 * Copyright (c) 1982, 1986, 1989 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)kern_time.c 7.15 (Berkeley) 3/17/91 34 * $Id: kern_time.c,v 1.2 1993/05/20 02:54:44 cgd Exp $ 35 */ 36 37 #include "param.h" 38 #include "resourcevar.h" 39 #include "kernel.h" 40 #include "proc.h" 41 42 #include "machine/cpu.h" 43 44 /* 45 * Time of day and interval timer support. 46 * 47 * These routines provide the kernel entry points to get and set 48 * the time-of-day and per-process interval timers. Subroutines 49 * here provide support for adding and subtracting timeval structures 50 * and decrementing interval timers, optionally reloading the interval 51 * timers when they expire. 52 */ 53 54 /* ARGSUSED */ 55 gettimeofday(p, uap, retval) 56 struct proc *p; 57 register struct args { 58 struct timeval *tp; 59 struct timezone *tzp; 60 } *uap; 61 int *retval; 62 { 63 struct timeval atv; 64 int error = 0; 65 66 if (uap->tp) { 67 microtime(&atv); 68 if (error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 69 sizeof (atv))) 70 return (error); 71 } 72 if (uap->tzp) 73 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 74 sizeof (tz)); 75 return (error); 76 } 77 78 /* ARGSUSED */ 79 settimeofday(p, uap, retval) 80 struct proc *p; 81 struct args { 82 struct timeval *tv; 83 struct timezone *tzp; 84 } *uap; 85 int *retval; 86 { 87 struct timeval atv; 88 struct timezone atz; 89 int error, s; 90 91 if (error = suser(p->p_ucred, &p->p_acflag)) 92 return (error); 93 if (uap->tv) { 94 if (error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 95 sizeof (struct timeval))) 96 return (error); 97 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 98 boottime.tv_sec += atv.tv_sec - time.tv_sec; 99 s = splhigh(); time = atv; splx(s); 100 resettodr(); 101 } 102 if (uap->tzp && (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, 103 sizeof (atz))) == 0) 104 tz = atz; 105 return (error); 106 } 107 108 extern int tickadj; /* "standard" clock skew, us./tick */ 109 int tickdelta; /* current clock skew, us. per tick */ 110 long timedelta; /* unapplied time correction, us. */ 111 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 112 113 /* ARGSUSED */ 114 adjtime(p, uap, retval) 115 struct proc *p; 116 register struct args { 117 struct timeval *delta; 118 struct timeval *olddelta; 119 } *uap; 120 int *retval; 121 { 122 struct timeval atv, oatv; 123 register long ndelta; 124 int s, error; 125 126 if (error = suser(p->p_ucred, &p->p_acflag)) 127 return (error); 128 if (error = 129 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof (struct timeval))) 130 return (error); 131 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 132 if (timedelta == 0) 133 if (ndelta > bigadj) 134 tickdelta = 10 * tickadj; 135 else 136 tickdelta = tickadj; 137 if (ndelta % tickdelta) 138 ndelta = ndelta / tickadj * tickadj; 139 140 s = splclock(); 141 if (uap->olddelta) { 142 oatv.tv_sec = timedelta / 1000000; 143 oatv.tv_usec = timedelta % 1000000; 144 } 145 timedelta = ndelta; 146 splx(s); 147 148 if (uap->olddelta) 149 (void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta, 150 sizeof (struct timeval)); 151 return (0); 152 } 153 154 /* 155 * Get value of an interval timer. The process virtual and 156 * profiling virtual time timers are kept in the p_stats area, since 157 * they can be swapped out. These are kept internally in the 158 * way they are specified externally: in time until they expire. 159 * 160 * The real time interval timer is kept in the process table slot 161 * for the process, and its value (it_value) is kept as an 162 * absolute time rather than as a delta, so that it is easy to keep 163 * periodic real-time signals from drifting. 164 * 165 * Virtual time timers are processed in the hardclock() routine of 166 * kern_clock.c. The real time timer is processed by a timeout 167 * routine, called from the softclock() routine. Since a callout 168 * may be delayed in real time due to interrupt processing in the system, 169 * it is possible for the real time timeout routine (realitexpire, given below), 170 * to be delayed in real time past when it is supposed to occur. It 171 * does not suffice, therefore, to reload the real timer .it_value from the 172 * real time timers .it_interval. Rather, we compute the next time in 173 * absolute time the timer should go off. 174 */ 175 /* ARGSUSED */ 176 getitimer(p, uap, retval) 177 struct proc *p; 178 register struct args { 179 u_int which; 180 struct itimerval *itv; 181 } *uap; 182 int *retval; 183 { 184 struct itimerval aitv; 185 int s; 186 187 if (uap->which > ITIMER_PROF) 188 return (EINVAL); 189 s = splclock(); 190 if (uap->which == ITIMER_REAL) { 191 /* 192 * Convert from absoulte to relative time in .it_value 193 * part of real time timer. If time for real time timer 194 * has passed return 0, else return difference between 195 * current time and time for the timer to go off. 196 */ 197 aitv = p->p_realtimer; 198 if (timerisset(&aitv.it_value)) 199 if (timercmp(&aitv.it_value, &time, <)) 200 timerclear(&aitv.it_value); 201 else 202 timevalsub(&aitv.it_value, &time); 203 } else 204 aitv = p->p_stats->p_timer[uap->which]; 205 splx(s); 206 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 207 sizeof (struct itimerval))); 208 } 209 210 /* ARGSUSED */ 211 setitimer(p, uap, retval) 212 struct proc *p; 213 register struct args { 214 u_int which; 215 struct itimerval *itv, *oitv; 216 } *uap; 217 int *retval; 218 { 219 struct itimerval aitv; 220 register struct itimerval *itvp; 221 int s, error; 222 223 if (uap->which > ITIMER_PROF) 224 return (EINVAL); 225 itvp = uap->itv; 226 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 227 sizeof(struct itimerval)))) 228 return (error); 229 if ((uap->itv = uap->oitv) && (error = getitimer(p, uap, retval))) 230 return (error); 231 if (itvp == 0) 232 return (0); 233 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 234 return (EINVAL); 235 s = splclock(); 236 if (uap->which == ITIMER_REAL) { 237 untimeout(realitexpire, (caddr_t)p); 238 if (timerisset(&aitv.it_value)) { 239 timevaladd(&aitv.it_value, &time); 240 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 241 } 242 p->p_realtimer = aitv; 243 } else 244 p->p_stats->p_timer[uap->which] = aitv; 245 splx(s); 246 return (0); 247 } 248 249 /* 250 * Real interval timer expired: 251 * send process whose timer expired an alarm signal. 252 * If time is not set up to reload, then just return. 253 * Else compute next time timer should go off which is > current time. 254 * This is where delay in processing this timeout causes multiple 255 * SIGALRM calls to be compressed into one. 256 */ 257 realitexpire(p) 258 register struct proc *p; 259 { 260 int s; 261 262 psignal(p, SIGALRM); 263 if (!timerisset(&p->p_realtimer.it_interval)) { 264 timerclear(&p->p_realtimer.it_value); 265 return; 266 } 267 for (;;) { 268 s = splclock(); 269 timevaladd(&p->p_realtimer.it_value, 270 &p->p_realtimer.it_interval); 271 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 272 timeout(realitexpire, (caddr_t)p, 273 hzto(&p->p_realtimer.it_value)); 274 splx(s); 275 return; 276 } 277 splx(s); 278 } 279 } 280 281 /* 282 * Check that a proposed value to load into the .it_value or 283 * .it_interval part of an interval timer is acceptable, and 284 * fix it to have at least minimal value (i.e. if it is less 285 * than the resolution of the clock, round it up.) 286 */ 287 itimerfix(tv) 288 struct timeval *tv; 289 { 290 291 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 292 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 293 return (EINVAL); 294 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 295 tv->tv_usec = tick; 296 return (0); 297 } 298 299 /* 300 * Decrement an interval timer by a specified number 301 * of microseconds, which must be less than a second, 302 * i.e. < 1000000. If the timer expires, then reload 303 * it. In this case, carry over (usec - old value) to 304 * reducint the value reloaded into the timer so that 305 * the timer does not drift. This routine assumes 306 * that it is called in a context where the timers 307 * on which it is operating cannot change in value. 308 */ 309 itimerdecr(itp, usec) 310 register struct itimerval *itp; 311 int usec; 312 { 313 314 if (itp->it_value.tv_usec < usec) { 315 if (itp->it_value.tv_sec == 0) { 316 /* expired, and already in next interval */ 317 usec -= itp->it_value.tv_usec; 318 goto expire; 319 } 320 itp->it_value.tv_usec += 1000000; 321 itp->it_value.tv_sec--; 322 } 323 itp->it_value.tv_usec -= usec; 324 usec = 0; 325 if (timerisset(&itp->it_value)) 326 return (1); 327 /* expired, exactly at end of interval */ 328 expire: 329 if (timerisset(&itp->it_interval)) { 330 itp->it_value = itp->it_interval; 331 itp->it_value.tv_usec -= usec; 332 if (itp->it_value.tv_usec < 0) { 333 itp->it_value.tv_usec += 1000000; 334 itp->it_value.tv_sec--; 335 } 336 } else 337 itp->it_value.tv_usec = 0; /* sec is already 0 */ 338 return (0); 339 } 340 341 /* 342 * Add and subtract routines for timevals. 343 * N.B.: subtract routine doesn't deal with 344 * results which are before the beginning, 345 * it just gets very confused in this case. 346 * Caveat emptor. 347 */ 348 timevaladd(t1, t2) 349 struct timeval *t1, *t2; 350 { 351 352 t1->tv_sec += t2->tv_sec; 353 t1->tv_usec += t2->tv_usec; 354 timevalfix(t1); 355 } 356 357 timevalsub(t1, t2) 358 struct timeval *t1, *t2; 359 { 360 361 t1->tv_sec -= t2->tv_sec; 362 t1->tv_usec -= t2->tv_usec; 363 timevalfix(t1); 364 } 365 366 timevalfix(t1) 367 struct timeval *t1; 368 { 369 370 if (t1->tv_usec < 0) { 371 t1->tv_sec--; 372 t1->tv_usec += 1000000; 373 } 374 if (t1->tv_usec >= 1000000) { 375 t1->tv_sec++; 376 t1->tv_usec -= 1000000; 377 } 378 } 379