1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 * 6 * @(#)kern_time.c 7.7 (Berkeley) 04/25/89 7 */ 8 9 #include "param.h" 10 #include "dir.h" /* XXX */ 11 #include "user.h" 12 #include "kernel.h" 13 #include "proc.h" 14 15 #include "machine/reg.h" 16 #include "machine/cpu.h" 17 18 /* 19 * Time of day and interval timer support. 20 * 21 * These routines provide the kernel entry points to get and set 22 * the time-of-day and per-process interval timers. Subroutines 23 * here provide support for adding and subtracting timeval structures 24 * and decrementing interval timers, optionally reloading the interval 25 * timers when they expire. 26 */ 27 28 gettimeofday() 29 { 30 register struct a { 31 struct timeval *tp; 32 struct timezone *tzp; 33 } *uap = (struct a *)u.u_ap; 34 struct timeval atv; 35 36 if (uap->tp) { 37 microtime(&atv); 38 u.u_error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 39 sizeof (atv)); 40 if (u.u_error) 41 return; 42 } 43 if (uap->tzp) 44 u.u_error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 45 sizeof (tz)); 46 } 47 48 settimeofday() 49 { 50 register struct a { 51 struct timeval *tv; 52 struct timezone *tzp; 53 } *uap = (struct a *)u.u_ap; 54 struct timeval atv; 55 struct timezone atz; 56 57 if (uap->tv) { 58 u.u_error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 59 sizeof (struct timeval)); 60 if (u.u_error) 61 return; 62 setthetime(&atv); 63 } 64 if (uap->tzp && suser()) { 65 u.u_error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, 66 sizeof (atz)); 67 if (u.u_error == 0) 68 tz = atz; 69 } 70 } 71 72 setthetime(tv) 73 struct timeval *tv; 74 { 75 int s; 76 77 if (!suser()) 78 return; 79 /* WHAT DO WE DO ABOUT PENDING REAL-TIME TIMEOUTS??? */ 80 boottime.tv_sec += tv->tv_sec - time.tv_sec; 81 s = splhigh(); time = *tv; splx(s); 82 resettodr(); 83 } 84 85 extern int tickadj; /* "standard" clock skew, us./tick */ 86 int tickdelta; /* current clock skew, us. per tick */ 87 long timedelta; /* unapplied time correction, us. */ 88 long bigadj = 1000000; /* use 10x skew above bigadj us. */ 89 90 adjtime() 91 { 92 register struct a { 93 struct timeval *delta; 94 struct timeval *olddelta; 95 } *uap = (struct a *)u.u_ap; 96 struct timeval atv, oatv; 97 register long ndelta; 98 int s; 99 100 if (!suser()) 101 return; 102 u.u_error = copyin((caddr_t)uap->delta, (caddr_t)&atv, 103 sizeof (struct timeval)); 104 if (u.u_error) 105 return; 106 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 107 if (timedelta == 0) 108 if (ndelta > bigadj) 109 tickdelta = 10 * tickadj; 110 else 111 tickdelta = tickadj; 112 if (ndelta % tickdelta) 113 ndelta = ndelta / tickadj * tickadj; 114 115 s = splclock(); 116 if (uap->olddelta) { 117 oatv.tv_sec = timedelta / 1000000; 118 oatv.tv_usec = timedelta % 1000000; 119 } 120 timedelta = ndelta; 121 splx(s); 122 123 if (uap->olddelta) 124 (void) copyout((caddr_t)&oatv, (caddr_t)uap->olddelta, 125 sizeof (struct timeval)); 126 } 127 128 /* 129 * Get value of an interval timer. The process virtual and 130 * profiling virtual time timers are kept in the u. area, since 131 * they can be swapped out. These are kept internally in the 132 * way they are specified externally: in time until they expire. 133 * 134 * The real time interval timer is kept in the process table slot 135 * for the process, and its value (it_value) is kept as an 136 * absolute time rather than as a delta, so that it is easy to keep 137 * periodic real-time signals from drifting. 138 * 139 * Virtual time timers are processed in the hardclock() routine of 140 * kern_clock.c. The real time timer is processed by a timeout 141 * routine, called from the softclock() routine. Since a callout 142 * may be delayed in real time due to interrupt processing in the system, 143 * it is possible for the real time timeout routine (realitexpire, given below), 144 * to be delayed in real time past when it is supposed to occur. It 145 * does not suffice, therefore, to reload the real timer .it_value from the 146 * real time timers .it_interval. Rather, we compute the next time in 147 * absolute time the timer should go off. 148 */ 149 getitimer() 150 { 151 register struct a { 152 u_int which; 153 struct itimerval *itv; 154 } *uap = (struct a *)u.u_ap; 155 struct itimerval aitv; 156 int s; 157 158 if (uap->which > ITIMER_PROF) { 159 u.u_error = EINVAL; 160 return; 161 } 162 s = splclock(); 163 if (uap->which == ITIMER_REAL) { 164 /* 165 * Convert from absoulte to relative time in .it_value 166 * part of real time timer. If time for real time timer 167 * has passed return 0, else return difference between 168 * current time and time for the timer to go off. 169 */ 170 aitv = u.u_procp->p_realtimer; 171 if (timerisset(&aitv.it_value)) 172 if (timercmp(&aitv.it_value, &time, <)) 173 timerclear(&aitv.it_value); 174 else 175 timevalsub(&aitv.it_value, &time); 176 } else 177 aitv = u.u_timer[uap->which]; 178 splx(s); 179 u.u_error = copyout((caddr_t)&aitv, (caddr_t)uap->itv, 180 sizeof (struct itimerval)); 181 } 182 183 setitimer() 184 { 185 register struct a { 186 u_int which; 187 struct itimerval *itv, *oitv; 188 } *uap = (struct a *)u.u_ap; 189 struct itimerval aitv; 190 register struct itimerval *itvp; 191 int s; 192 register struct proc *p = u.u_procp; 193 194 if (uap->which > ITIMER_PROF) { 195 u.u_error = EINVAL; 196 return; 197 } 198 itvp = uap->itv; 199 if (itvp && (u.u_error = copyin((caddr_t)itvp, (caddr_t)&aitv, 200 sizeof(struct itimerval)))) 201 return; 202 if (uap->itv = uap->oitv) { 203 getitimer(); 204 if (u.u_error) 205 return; 206 } 207 if (itvp == 0) 208 return; 209 if (itimerfix(&aitv.it_value) || itimerfix(&aitv.it_interval)) { 210 u.u_error = EINVAL; 211 return; 212 } 213 s = splclock(); 214 if (uap->which == ITIMER_REAL) { 215 untimeout(realitexpire, (caddr_t)p); 216 if (timerisset(&aitv.it_value)) { 217 timevaladd(&aitv.it_value, &time); 218 timeout(realitexpire, (caddr_t)p, hzto(&aitv.it_value)); 219 } 220 p->p_realtimer = aitv; 221 } else 222 u.u_timer[uap->which] = aitv; 223 splx(s); 224 } 225 226 /* 227 * Real interval timer expired: 228 * send process whose timer expired an alarm signal. 229 * If time is not set up to reload, then just return. 230 * Else compute next time timer should go off which is > current time. 231 * This is where delay in processing this timeout causes multiple 232 * SIGALRM calls to be compressed into one. 233 */ 234 realitexpire(p) 235 register struct proc *p; 236 { 237 int s; 238 239 psignal(p, SIGALRM); 240 if (!timerisset(&p->p_realtimer.it_interval)) { 241 timerclear(&p->p_realtimer.it_value); 242 return; 243 } 244 for (;;) { 245 s = splclock(); 246 timevaladd(&p->p_realtimer.it_value, 247 &p->p_realtimer.it_interval); 248 if (timercmp(&p->p_realtimer.it_value, &time, >)) { 249 timeout(realitexpire, (caddr_t)p, 250 hzto(&p->p_realtimer.it_value)); 251 splx(s); 252 return; 253 } 254 splx(s); 255 } 256 } 257 258 /* 259 * Check that a proposed value to load into the .it_value or 260 * .it_interval part of an interval timer is acceptable, and 261 * fix it to have at least minimal value (i.e. if it is less 262 * than the resolution of the clock, round it up.) 263 */ 264 itimerfix(tv) 265 struct timeval *tv; 266 { 267 268 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 269 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 270 return (EINVAL); 271 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 272 tv->tv_usec = tick; 273 return (0); 274 } 275 276 /* 277 * Decrement an interval timer by a specified number 278 * of microseconds, which must be less than a second, 279 * i.e. < 1000000. If the timer expires, then reload 280 * it. In this case, carry over (usec - old value) to 281 * reducint the value reloaded into the timer so that 282 * the timer does not drift. This routine assumes 283 * that it is called in a context where the timers 284 * on which it is operating cannot change in value. 285 */ 286 itimerdecr(itp, usec) 287 register struct itimerval *itp; 288 int usec; 289 { 290 291 if (itp->it_value.tv_usec < usec) { 292 if (itp->it_value.tv_sec == 0) { 293 /* expired, and already in next interval */ 294 usec -= itp->it_value.tv_usec; 295 goto expire; 296 } 297 itp->it_value.tv_usec += 1000000; 298 itp->it_value.tv_sec--; 299 } 300 itp->it_value.tv_usec -= usec; 301 usec = 0; 302 if (timerisset(&itp->it_value)) 303 return (1); 304 /* expired, exactly at end of interval */ 305 expire: 306 if (timerisset(&itp->it_interval)) { 307 itp->it_value = itp->it_interval; 308 itp->it_value.tv_usec -= usec; 309 if (itp->it_value.tv_usec < 0) { 310 itp->it_value.tv_usec += 1000000; 311 itp->it_value.tv_sec--; 312 } 313 } else 314 itp->it_value.tv_usec = 0; /* sec is already 0 */ 315 return (0); 316 } 317 318 /* 319 * Add and subtract routines for timevals. 320 * N.B.: subtract routine doesn't deal with 321 * results which are before the beginning, 322 * it just gets very confused in this case. 323 * Caveat emptor. 324 */ 325 timevaladd(t1, t2) 326 struct timeval *t1, *t2; 327 { 328 329 t1->tv_sec += t2->tv_sec; 330 t1->tv_usec += t2->tv_usec; 331 timevalfix(t1); 332 } 333 334 timevalsub(t1, t2) 335 struct timeval *t1, *t2; 336 { 337 338 t1->tv_sec -= t2->tv_sec; 339 t1->tv_usec -= t2->tv_usec; 340 timevalfix(t1); 341 } 342 343 timevalfix(t1) 344 struct timeval *t1; 345 { 346 347 if (t1->tv_usec < 0) { 348 t1->tv_sec--; 349 t1->tv_usec += 1000000; 350 } 351 if (t1->tv_usec >= 1000000) { 352 t1->tv_sec++; 353 t1->tv_usec -= 1000000; 354 } 355 } 356