1 /* $NetBSD: kern_time.c,v 1.11 1994/10/20 04:22:59 cgd Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93 36 */ 37 38 #include <sys/param.h> 39 #include <sys/resourcevar.h> 40 #include <sys/kernel.h> 41 #include <sys/systm.h> 42 #include <sys/proc.h> 43 #include <sys/vnode.h> 44 45 #include <sys/mount.h> 46 #include <sys/syscallargs.h> 47 48 #include <machine/cpu.h> 49 50 /* 51 * Time of day and interval timer support. 52 * 53 * These routines provide the kernel entry points to get and set 54 * the time-of-day and per-process interval timers. Subroutines 55 * here provide support for adding and subtracting timeval structures 56 * and decrementing interval timers, optionally reloading the interval 57 * timers when they expire. 58 */ 59 60 /* ARGSUSED */ 61 int 62 gettimeofday(p, uap, retval) 63 struct proc *p; 64 register struct gettimeofday_args /* { 65 syscallarg(struct timeval *) tp; 66 syscallarg(struct timezone *) tzp; 67 } */ *uap; 68 register_t *retval; 69 { 70 struct timeval atv; 71 int error = 0; 72 73 if (SCARG(uap, tp)) { 74 microtime(&atv); 75 if (error = copyout((caddr_t)&atv, (caddr_t)SCARG(uap, tp), 76 sizeof (atv))) 77 return (error); 78 } 79 if (SCARG(uap, tzp)) 80 error = copyout((caddr_t)&tz, (caddr_t)SCARG(uap, tzp), 81 sizeof (tz)); 82 return (error); 83 } 84 85 /* ARGSUSED */ 86 int 87 settimeofday(p, uap, retval) 88 struct proc *p; 89 struct settimeofday_args /* { 90 syscallarg(struct timeval *) tv; 91 syscallarg(struct timezone *) tzp; 92 } */ *uap; 93 register_t *retval; 94 { 95 struct timeval atv, delta; 96 struct timezone atz; 97 int error, s; 98 99 if (error = suser(p->p_ucred, &p->p_acflag)) 100 return (error); 101 /* Verify all parameters before changing time. */ 102 if (SCARG(uap, tv) && (error = copyin((caddr_t)SCARG(uap, tv), 103 (caddr_t)&atv, sizeof(atv)))) 104 return (error); 105 if (SCARG(uap, tzp) && (error = copyin((caddr_t)SCARG(uap, tzp), 106 (caddr_t)&atz, sizeof(atz)))) 107 return (error); 108 if (SCARG(uap, tv)) { 109 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 110 s = splclock(); 111 /* nb. delta.tv_usec may be < 0, but this is OK here */ 112 delta.tv_sec = atv.tv_sec - time.tv_sec; 113 delta.tv_usec = atv.tv_usec - time.tv_usec; 114 time = atv; 115 (void) splsoftclock(); 116 timevaladd(&boottime, &delta); 117 timevalfix(&boottime); 118 timevaladd(&runtime, &delta); 119 timevalfix(&runtime); 120 LEASE_UPDATETIME(delta.tv_sec); 121 splx(s); 122 resettodr(); 123 } 124 if (SCARG(uap, tzp)) 125 tz = atz; 126 return (0); 127 } 128 129 int tickdelta; /* current clock skew, us. per tick */ 130 long timedelta; /* unapplied time correction, us. */ 131 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 132 133 /* ARGSUSED */ 134 int 135 adjtime(p, uap, retval) 136 struct proc *p; 137 register struct adjtime_args /* { 138 syscallarg(struct timeval *) delta; 139 syscallarg(struct timeval *) olddelta; 140 } */ *uap; 141 register_t *retval; 142 { 143 struct timeval atv; 144 register long ndelta, ntickdelta, odelta; 145 int s, error; 146 147 if (error = suser(p->p_ucred, &p->p_acflag)) 148 return (error); 149 if (error = copyin((caddr_t)SCARG(uap, delta), (caddr_t)&atv, 150 sizeof(struct timeval))) 151 return (error); 152 153 /* 154 * Compute the total correction and the rate at which to apply it. 155 * Round the adjustment down to a whole multiple of the per-tick 156 * delta, so that after some number of incremental changes in 157 * hardclock(), tickdelta will become zero, lest the correction 158 * overshoot and start taking us away from the desired final time. 159 */ 160 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 161 if (ndelta > bigadj) 162 ntickdelta = 10 * tickadj; 163 else 164 ntickdelta = tickadj; 165 if (ndelta % ntickdelta) 166 ndelta = ndelta / ntickdelta * ntickdelta; 167 168 /* 169 * To make hardclock()'s job easier, make the per-tick delta negative 170 * if we want time to run slower; then hardclock can simply compute 171 * tick + tickdelta, and subtract tickdelta from timedelta. 172 */ 173 if (ndelta < 0) 174 ntickdelta = -ntickdelta; 175 s = splclock(); 176 odelta = timedelta; 177 timedelta = ndelta; 178 tickdelta = ntickdelta; 179 splx(s); 180 181 if (SCARG(uap, olddelta)) { 182 atv.tv_sec = odelta / 1000000; 183 atv.tv_usec = odelta % 1000000; 184 (void) copyout((caddr_t)&atv, (caddr_t)SCARG(uap, olddelta), 185 sizeof(struct timeval)); 186 } 187 return (0); 188 } 189 190 /* 191 * Get value of an interval timer. The process virtual and 192 * profiling virtual time timers are kept in the p_stats area, since 193 * they can be swapped out. These are kept internally in the 194 * way they are specified externally: in time until they expire. 195 * 196 * The real time interval timer is kept in the process table slot 197 * for the process, and its value (it_value) is kept as an 198 * absolute time rather than as a delta, so that it is easy to keep 199 * periodic real-time signals from drifting. 200 * 201 * Virtual time timers are processed in the hardclock() routine of 202 * kern_clock.c. The real time timer is processed by a timeout 203 * routine, called from the softclock() routine. Since a callout 204 * may be delayed in real time due to interrupt processing in the system, 205 * it is possible for the real time timeout routine (realitexpire, given below), 206 * to be delayed in real time past when it is supposed to occur. It 207 * does not suffice, therefore, to reload the real timer .it_value from the 208 * real time timers .it_interval. Rather, we compute the next time in 209 * absolute time the timer should go off. 210 */ 211 /* ARGSUSED */ 212 int 213 getitimer(p, uap, retval) 214 struct proc *p; 215 register struct getitimer_args /* { 216 syscallarg(u_int) which; 217 syscallarg(struct itimerval *) itv; 218 } */ *uap; 219 register_t *retval; 220 { 221 struct itimerval aitv; 222 int s; 223 224 if (SCARG(uap, which) > ITIMER_PROF) 225 return (EINVAL); 226 s = splclock(); 227 if (SCARG(uap, which) == ITIMER_REAL) { 228 /* 229 * Convert from absoulte to relative time in .it_value 230 * part of real time timer. If time for real time timer 231 * has passed return 0, else return difference between 232 * current time and time for the timer to go off. 233 */ 234 aitv = p->p_realtimer; 235 if (timerisset(&aitv.it_value)) 236 if (timercmp(&aitv.it_value, &time, <)) 237 timerclear(&aitv.it_value); 238 else 239 timevalsub(&aitv.it_value, 240 (struct timeval *)&time); 241 } else 242 aitv = p->p_stats->p_timer[SCARG(uap, which)]; 243 splx(s); 244 return (copyout((caddr_t)&aitv, (caddr_t)SCARG(uap, itv), 245 sizeof (struct itimerval))); 246 } 247 248 /* ARGSUSED */ 249 int 250 setitimer(p, uap, retval) 251 struct proc *p; 252 register struct setitimer_args /* { 253 syscallarg(u_int) which; 254 syscallarg(struct itimerval *) itv; 255 syscallarg(struct itimerval *) oitv; 256 } */ *uap; 257 register_t *retval; 258 { 259 struct itimerval aitv; 260 register struct itimerval *itvp; 261 int s, error; 262 263 if (SCARG(uap, which) > ITIMER_PROF) 264 return (EINVAL); 265 itvp = SCARG(uap, itv); 266 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 267 sizeof(struct itimerval)))) 268 return (error); 269 if ((SCARG(uap, itv) = SCARG(uap, oitv)) && 270 (error = getitimer(p, uap, retval))) 271 return (error); 272 if (itvp == 0) 273 return (0); 274 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) 275 return (EINVAL); 276 s = splclock(); 277 if (SCARG(uap, which) == ITIMER_REAL) { 278 untimeout(realitexpire, p); 279 if (timerisset(&aitv.it_value)) { 280 timevaladd(&aitv.it_value, (struct timeval *)&time); 281 timeout(realitexpire, p, hzto(&aitv.it_value)); 282 } 283 p->p_realtimer = aitv; 284 } else 285 p->p_stats->p_timer[SCARG(uap, which)] = aitv; 286 splx(s); 287 return (0); 288 } 289 290 /* 291 * Real interval timer expired: 292 * send process whose timer expired an alarm signal. 293 * If time is not set up to reload, then just return. 294 * Else compute next time timer should go off which is > current time. 295 * This is where delay in processing this timeout causes multiple 296 * SIGALRM calls to be compressed into one. 297 */ 298 void 299 realitexpire(arg) 300 void *arg; 301 { 302 register struct proc *p; 303 int s; 304 305 p = (struct proc *)arg; 306 psignal(p, SIGALRM); 307 if (!timerisset(&p->p_realtimer.it_interval)) { 308 timerclear(&p->p_realtimer.it_value); 309 return; 310 } 311 for (;;) { 312 s = splclock(); 313 timevaladd(&p->p_realtimer.it_value, 314 &p->p_realtimer.it_interval); 315 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 316 timeout(realitexpire, p, 317 hzto(&p->p_realtimer.it_value)); 318 splx(s); 319 return; 320 } 321 splx(s); 322 } 323 } 324 325 /* 326 * Check that a proposed value to load into the .it_value or 327 * .it_interval part of an interval timer is acceptable, and 328 * fix it to have at least minimal value (i.e. if it is less 329 * than the resolution of the clock, round it up.) 330 */ 331 int 332 itimerfix(tv) 333 struct timeval *tv; 334 { 335 336 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 337 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 338 return (EINVAL); 339 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 340 tv->tv_usec = tick; 341 return (0); 342 } 343 344 /* 345 * Decrement an interval timer by a specified number 346 * of microseconds, which must be less than a second, 347 * i.e. < 1000000. If the timer expires, then reload 348 * it. In this case, carry over (usec - old value) to 349 * reduce the value reloaded into the timer so that 350 * the timer does not drift. This routine assumes 351 * that it is called in a context where the timers 352 * on which it is operating cannot change in value. 353 */ 354 int 355 itimerdecr(itp, usec) 356 register struct itimerval *itp; 357 int usec; 358 { 359 360 if (itp->it_value.tv_usec < usec) { 361 if (itp->it_value.tv_sec == 0) { 362 /* expired, and already in next interval */ 363 usec -= itp->it_value.tv_usec; 364 goto expire; 365 } 366 itp->it_value.tv_usec += 1000000; 367 itp->it_value.tv_sec--; 368 } 369 itp->it_value.tv_usec -= usec; 370 usec = 0; 371 if (timerisset(&itp->it_value)) 372 return (1); 373 /* expired, exactly at end of interval */ 374 expire: 375 if (timerisset(&itp->it_interval)) { 376 itp->it_value = itp->it_interval; 377 itp->it_value.tv_usec -= usec; 378 if (itp->it_value.tv_usec < 0) { 379 itp->it_value.tv_usec += 1000000; 380 itp->it_value.tv_sec--; 381 } 382 } else 383 itp->it_value.tv_usec = 0; /* sec is already 0 */ 384 return (0); 385 } 386 387 /* 388 * Add and subtract routines for timevals. 389 * N.B.: subtract routine doesn't deal with 390 * results which are before the beginning, 391 * it just gets very confused in this case. 392 * Caveat emptor. 393 */ 394 void 395 timevaladd(t1, t2) 396 struct timeval *t1, *t2; 397 { 398 399 t1->tv_sec += t2->tv_sec; 400 t1->tv_usec += t2->tv_usec; 401 timevalfix(t1); 402 } 403 404 void 405 timevalsub(t1, t2) 406 struct timeval *t1, *t2; 407 { 408 409 t1->tv_sec -= t2->tv_sec; 410 t1->tv_usec -= t2->tv_usec; 411 timevalfix(t1); 412 } 413 414 void 415 timevalfix(t1) 416 struct timeval *t1; 417 { 418 419 if (t1->tv_usec < 0) { 420 t1->tv_sec--; 421 t1->tv_usec += 1000000; 422 } 423 if (t1->tv_usec >= 1000000) { 424 t1->tv_sec++; 425 t1->tv_usec -= 1000000; 426 } 427 } 428