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Annotation of coherent/d/286_KERNEL/USRSRC/coh/proc.c, revision 1.1

1.1     ! root        1: /* $Header: /newbits/286_KERNEL/USRSRC/coh/RCS/proc.c,v 1.1 92/01/09 13:29:01 bin Exp Locker: bin $ */
        !             2: /* (lgl-
        !             3:  *     The information contained herein is a trade secret of Mark Williams
        !             4:  *     Company, and  is confidential information.  It is provided  under a
        !             5:  *     license agreement,  and may be  copied or disclosed  only under the
        !             6:  *     terms of  that agreement.  Any  reproduction or disclosure  of this
        !             7:  *     material without the express written authorization of Mark Williams
        !             8:  *     Company or persuant to the license agreement is unlawful.
        !             9:  *
        !            10:  *     COHERENT Version 2.3.37
        !            11:  *     Copyright (c) 1982, 1983, 1984.
        !            12:  *     An unpublished work by Mark Williams Company, Chicago.
        !            13:  *     All rights reserved.
        !            14:  -lgl) */
        !            15: /*
        !            16:  * Coherent.
        !            17:  * Process handling and scheduling.
        !            18:  *
        !            19:  * $Log:       proc.c,v $
        !            20:  * Revision 1.1  92/01/09  13:29:01  bin
        !            21:  * Initial revision
        !            22:  * 
        !            23:  * Revision 1.2        88/08/05  15:30:01      src
        !            24:  * pfork() made more rigorous, supports loadable driver forks, etc.
        !            25:  * lock/unlock more efficient, since know wakeup is synchronous.
        !            26:  * 
        !            27:  * Revision 1.1        88/03/24  16:14:16      src
        !            28:  * Initial revision
        !            29:  * 
        !            30:  * 88/03/10    Allan Cornish           /usr/src/sys/coh/proc.c
        !            31:  * Numerous temporary fixes due to AMD 286 chip being buggy in protected mode.
        !            32:  * These partial fixes will be removed once all CPU's are replaced.
        !            33:  *
        !            34:  * 88/01/21    Allan Cornish           /usr/src/sys/coh/proc.c
        !            35:  * Race condition caused by pexit() calling sfree() on the user-area
        !            36:  * when the segmentation gate is locked is now prevented.
        !            37:  * Release of the user area now deferred until relproc() invoked by uwait().
        !            38:  *
        !            39:  * 87/11/13    Allan Cornish           /usr/src/sys/coh/proc.c
        !            40:  * pexit() now sets uasa to 0 before dispatching processor.
        !            41:  *
        !            42:  * 87/11/05    Allan Cornish           /usr/src/sys/coh/proc.c
        !            43:  * New seg struct now used to allow extended addressing.
        !            44:  *
        !            45:  * 87/07/08    Allan Cornish           /usr/src/sys/coh/proc.c
        !            46:  * pexit() now cancels poll/alarm timed functions before terminating.
        !            47:  *
        !            48:  * 87/01/05    Allan Cornish           /usr/src/sys/coh/proc.c
        !            49:  * pexit() now wakes the swapper before terminating.
        !            50:  */
        !            51: #include <sys/coherent.h>
        !            52: #include <acct.h>
        !            53: #include <errno.h>
        !            54: #include <sys/inode.h>
        !            55: #include <sys/proc.h>
        !            56: #include <sys/ptrace.h>
        !            57: #include <sys/sched.h>
        !            58: #include <sys/seg.h>
        !            59: #include <signal.h>
        !            60: #include <sys/stat.h>
        !            61: #include <sys/uproc.h>
        !            62: 
        !            63: /*
        !            64:  * Initialisation.
        !            65:  * Set up the hash table queues.
        !            66:  */
        !            67: pcsinit()
        !            68: {
        !            69:        register PROC *pp;
        !            70:        register PLINK *lp;
        !            71: 
        !            72:        pp = &procq;
        !            73:        SELF = pp;
        !            74:        procq.p_nforw = pp;
        !            75:        procq.p_nback = pp;
        !            76:        procq.p_lforw = pp;
        !            77:        procq.p_lback = pp;
        !            78:        for (lp=&linkq[0]; lp<&linkq[NHPLINK]; lp++) {
        !            79:                lp->p_lforw = lp;
        !            80:                lp->p_lback = lp;
        !            81:        }
        !            82: }
        !            83: 
        !            84: /*
        !            85:  * Initiate a process.  `f' is a kernel function that is associated with
        !            86:  * the process.
        !            87:  */
        !            88: PROC *
        !            89: process(f)
        !            90: int (*f)();
        !            91: {
        !            92:        register PROC *pp1;
        !            93:        register PROC *pp;
        !            94:        register SEG *sp;
        !            95:        MCON mcon;
        !            96: 
        !            97:        if ((pp=kalloc(sizeof(PROC))) == NULL)
        !            98:                return (NULL);
        !            99: 
        !           100:        pp->p_flags = PFCORE;
        !           101:        pp->p_state = PSRUN;
        !           102:        pp->p_ttdev = NODEV;
        !           103: 
        !           104:        if (f != NULL) {
        !           105:                pp->p_flags |= PFKERN;
        !           106:                sp = salloc((fsize_t)UPASIZE, SFSYST|SFHIGH|SFNSWP);
        !           107:                if (sp == NULL) {
        !           108:                        kfree(pp);
        !           109:                        return (NULL);
        !           110:                }
        !           111:                pp->p_segp[SIUSERP] = sp;
        !           112:                msetsys( &mcon, f, FP_SEL(sp->s_faddr) );
        !           113:                kfcopy( (char *)&mcon,
        !           114:                        sp->s_faddr + offset(uproc, u_syscon),
        !           115:                        sizeof(mcon) );
        !           116:        }
        !           117:        lock(pnxgate);
        !           118: next:
        !           119:        pp->p_pid = cpid++;
        !           120:        if (cpid >= NPID)
        !           121:                cpid = 2;
        !           122:        pp1 = &procq;
        !           123:        while ((pp1=pp1->p_nforw) != &procq) {
        !           124:                if (pp1->p_pid < pp->p_pid)
        !           125:                        break;
        !           126:                if (pp1->p_pid == pp->p_pid)
        !           127:                        goto next;
        !           128:        }
        !           129:        pp->p_nback = pp1->p_nback;
        !           130:        pp1->p_nback->p_nforw = pp;
        !           131:        pp->p_nforw = pp1;
        !           132:        pp1->p_nback = pp;
        !           133:        unlock(pnxgate);
        !           134:        return (pp);
        !           135: }
        !           136: 
        !           137: /*
        !           138:  * Remove a process from the next queue and release and space.
        !           139:  */
        !           140: relproc(pp)
        !           141: register PROC *pp;
        !           142: {
        !           143:        register SEG * sp;
        !           144: 
        !           145:        /*
        !           146:         * Child process still has a user-area.
        !           147:         */
        !           148:        if ( (sp = pp->p_segp[SIUSERP]) != NULL ) {
        !           149: 
        !           150:                /*
        !           151:                 * Detach user-area from child process.
        !           152:                 */
        !           153:                pp->p_segp[SIUSERP] = NULL;
        !           154: 
        !           155:                /*
        !           156:                 * Child process is swapped out.
        !           157:                 */
        !           158:                if ( pp->p_flags & PFSWAP )
        !           159:                        sp->s_lrefc++;
        !           160: 
        !           161:                /*
        !           162:                 * Release child's user-area.
        !           163:                 */
        !           164:                sfree( sp );
        !           165:        }
        !           166: 
        !           167:        /*
        !           168:         * Remove process from doubly-linked list of all processes.
        !           169:         * Release space allocated for proc structure.
        !           170:         */
        !           171:        lock(pnxgate);
        !           172:        pp->p_nback->p_nforw = pp->p_nforw;
        !           173:        pp->p_nforw->p_nback = pp->p_nback;
        !           174:        unlock(pnxgate);
        !           175:        kfree(pp);
        !           176: }
        !           177: 
        !           178: /*
        !           179:  * Create a clone of ourselves.
        !           180:  *     N.B. - consave(&mcon) returns twice; anything not initialized
        !           181:  *     in automatic storage before the call to segadup() will not be
        !           182:  *     initialized when the second return from consave() commences.
        !           183:  */
        !           184: pfork()
        !           185: {
        !           186:        register PROC *cpp;
        !           187:        register PROC *pp;
        !           188:        register int s;
        !           189:        MCON mcon;
        !           190: 
        !           191:        if ((cpp=process(NULL)) == NULL) {
        !           192:                u.u_error = EAGAIN;
        !           193:                return;
        !           194:        }
        !           195: 
        !           196:        s = sphi();     /* Make usave a null macro if unnecessary */
        !           197:        usave();        /* Put the current copy of uarea into its segment */
        !           198:        spl(s);
        !           199: 
        !           200:        if (segadup(cpp) == 0) {
        !           201:                u.u_error = EAGAIN;
        !           202:                relproc(cpp);
        !           203:                return;
        !           204:        }
        !           205:        if ( u.u_rdir != NULL )
        !           206:                u.u_rdir->i_refc++;
        !           207:        if ( u.u_cdir != NULL )
        !           208:                u.u_cdir->i_refc++;
        !           209:        fdadupl();
        !           210:        pp = SELF;
        !           211:        cpp->p_uid   = pp->p_uid;
        !           212:        cpp->p_ruid  = pp->p_ruid;
        !           213:        cpp->p_rgid  = pp->p_rgid;
        !           214:        cpp->p_ppid  = pp->p_pid;
        !           215:        cpp->p_ttdev = pp->p_ttdev;
        !           216:        cpp->p_group = pp->p_group;
        !           217:        cpp->p_ssig  = pp->p_ssig;
        !           218:        cpp->p_isig  = pp->p_isig;
        !           219:        cpp->p_cval  = CVCHILD;
        !           220:        cpp->p_ival  = IVCHILD;
        !           221:        cpp->p_sval  = SVCHILD;
        !           222:        cpp->p_rval  = RVCHILD;
        !           223: 
        !           224:        s = sphi();
        !           225:        consave(&mcon);
        !           226:        spl( s );
        !           227: 
        !           228:        /*
        !           229:         * Parent process.
        !           230:         */
        !           231:        if ( (pp = SELF) != cpp ) {
        !           232:                segfinm(cpp->p_segp[SIUSERP]);
        !           233:                kfcopy( (char *)&mcon,
        !           234:                        cpp->p_segp[SIUSERP]->s_faddr + offset(uproc,u_syscon),
        !           235:                        sizeof(mcon) );
        !           236:                mfixcon(cpp);
        !           237:                s = sphi();
        !           238:                setrun(cpp);
        !           239:                spl(s);
        !           240:                return( cpp->p_pid );
        !           241:        }
        !           242: 
        !           243:        /*
        !           244:         * Child process.
        !           245:         */
        !           246:        else {
        !           247:                u.u_btime = timer.t_time;
        !           248:                u.u_flag = AFORK;
        !           249:                /* for (i=0; i<NUSEG; i++) done in sproto */
        !           250:                        /* u.u_segl[i].sr_segp = pp->p_segp[i]; ditto */
        !           251:                sproto();
        !           252:                segload();
        !           253:                return( 0 );
        !           254:        }
        !           255: }
        !           256: 
        !           257: /*
        !           258:  * Die.
        !           259:  */
        !           260: pexit(s)
        !           261: {
        !           262:        register PROC *pp1;
        !           263:        register PROC *pp;
        !           264:        register SEG  *sp;
        !           265:        register int n;
        !           266: 
        !           267:        pp = SELF;
        !           268: 
        !           269:        /*
        !           270:         * Cancel alarm and poll timers [if any].
        !           271:         */
        !           272:        timeout( &pp->p_alrmtim, 0, NULL, 0 );
        !           273:        timeout( &pp->p_polltim, 0, NULL, 0 );
        !           274: 
        !           275:        /*
        !           276:         * Write out accounting directory and close all files associated with
        !           277:         * this process.
        !           278:         */
        !           279:        setacct();
        !           280:        if ( u.u_rdir )
        !           281:                ldetach(u.u_rdir);
        !           282:        if ( u.u_cdir )
        !           283:                ldetach(u.u_cdir);
        !           284:        fdaclose();
        !           285: 
        !           286:        /*
        !           287:         * Free all segments in reverse order, except for user-area.
        !           288:         */
        !           289:        for ( n = NUSEG; --n > 0; ) {
        !           290:                if ( (sp = pp->p_segp[n]) != NULL ) {
        !           291:                        pp->p_segp[n] = NULL;
        !           292:                        sfree( sp );
        !           293:                }
        !           294:        }
        !           295: 
        !           296:        /*
        !           297:         * Wakeup our parent.  If we have any children, init will become the
        !           298:         * new parent.  If there are any children we are tracing who are
        !           299:         * waiting for us, we wake them up.
        !           300:         */
        !           301:        pp1 = &procq;
        !           302:        while ((pp1=pp1->p_nforw) != &procq) {
        !           303:                if (pp1->p_pid == pp->p_ppid) {
        !           304:                        if (pp1->p_state==PSSLEEP && pp1->p_event==(char *)pp1)
        !           305:                                wakeup((char *)pp1);
        !           306:                }
        !           307:                if (pp1->p_ppid == pp->p_pid) {
        !           308:                        pp1->p_ppid = 1;
        !           309:                        if (pp1->p_state == PSDEAD)
        !           310:                                wakeup((char *)eprocp);
        !           311:                        if ((pp1->p_flags&PFTRAC) != 0)
        !           312:                                wakeup((char *)&pts.pt_req);
        !           313:                }
        !           314:        }
        !           315: 
        !           316:        /*
        !           317:         * Wake up swapper if swap timer is active.
        !           318:         */
        !           319:        if ( stimer.t_last != 0 )
        !           320:                wakeup( (char *) &stimer );
        !           321: 
        !           322:        /*
        !           323:         * And finally mark us as dead and give up the processor forever.
        !           324:         */
        !           325:        pp->p_exit = s;
        !           326:        pp->p_state = PSDEAD;
        !           327:        uasa = 0;
        !           328:        dispatch();
        !           329: }
        !           330: 
        !           331: /*
        !           332:  * Sleep on the event `e'.  This gives up the processor until someone
        !           333:  * wakes us up.  Since it is possible for many people to sleep on the
        !           334:  * same event, the caller when awakened should make sure that what he
        !           335:  * was waiting for has completed and if not, go to sleep again.  `cl'
        !           336:  * is the cpu value we get to get the cpu as soon as we are woken up.
        !           337:  * `sl' is the swap value we get to keep us in memory for the duration
        !           338:  * of the sleep.  `sr' is the swap value that allows us to get swapped
        !           339:  * in if we have been swapped out.
        !           340:  */
        !           341: sleep(e, cl, sl, sr)
        !           342: char *e;
        !           343: {
        !           344:        register PROC *bp;
        !           345:        register PROC *fp;
        !           346:        register PROC *pp;
        !           347:        register int s;
        !           348: 
        !           349:        pp = SELF;
        !           350: 
        !           351:        /*
        !           352:         * See if we have a signal awaiting.
        !           353:         */
        !           354:        if (cl<CVNOSIG && pp->p_ssig && nondsig()) {
        !           355:                sphi();
        !           356:                envrest(&u.u_sigenv);
        !           357:        }
        !           358: 
        !           359:        /*
        !           360:         * Get ready to go to sleep and do so.
        !           361:         */
        !           362:        s = sphi();
        !           363:        pp->p_state = PSSLEEP;
        !           364:        pp->p_event = e;
        !           365:        pp->p_lctim = utimer;
        !           366:        addu(pp->p_cval, cl);
        !           367:        pp->p_ival = sl;
        !           368:        pp->p_rval = sr;
        !           369:        fp = &linkq[hash(e)];
        !           370:        bp = fp->p_lback;
        !           371:        pp->p_lforw = fp;
        !           372:        fp->p_lback = pp;
        !           373:        pp->p_lback = bp;
        !           374:        bp->p_lforw = pp;
        !           375:        spl(s);
        !           376:        dispatch();
        !           377: 
        !           378:        /*
        !           379:         * We have just woken up.  Get ready to return.
        !           380:         */
        !           381:        subu(pp->p_cval, cl);
        !           382:        pp->p_ival = 0;
        !           383:        pp->p_rval = 0;
        !           384: 
        !           385:        /*
        !           386:         * Check for an interrupted system call.
        !           387:         */
        !           388:        if (cl<CVNOSIG && pp->p_ssig && nondsig()) {
        !           389:                sphi();
        !           390:                envrest(&u.u_sigenv);
        !           391:        }
        !           392: }
        !           393: 
        !           394: /*
        !           395:  * Defer function to wake up all processes sleeping on the event `e'.
        !           396:  */
        !           397: wakeup(e)
        !           398: char *e;
        !           399: {
        !           400:        extern void dwakeup();
        !           401: 
        !           402:        defer( dwakeup, e );
        !           403: }
        !           404: 
        !           405: /*
        !           406:  * Wake up all processes sleeping on the event `e'.
        !           407:  */
        !           408: static void
        !           409: dwakeup( e )
        !           410: char *e;
        !           411: {
        !           412:        register PROC *pp;
        !           413:        register PROC *pp1;
        !           414:        register int s;
        !           415: 
        !           416:        /*
        !           417:         * Identify event queue to check.
        !           418:         * Disable interrupts.
        !           419:         */
        !           420:        pp1 = &linkq[hash(e)];
        !           421:        pp = pp1;
        !           422:        s = sphi();
        !           423: 
        !           424:        /*
        !           425:         * Traverse doubly-linked circular event-queue.
        !           426:         */
        !           427:        while ( (pp = pp->p_lforw) != pp1 ) {
        !           428: 
        !           429:                /*
        !           430:                 * Process is waiting on event 'e'.
        !           431:                 */
        !           432:                if ( pp->p_event == e ) {
        !           433:                        /*
        !           434:                         * Remove process from event queue.
        !           435:                         * Update process priority.
        !           436:                         * Insert process into run queue.
        !           437:                         */
        !           438:                        pp->p_lback->p_lforw = pp->p_lforw;
        !           439:                        pp->p_lforw->p_lback = pp->p_lback;
        !           440:                        addu( pp->p_cval, (utimer-pp->p_lctim)*CVCLOCK );
        !           441:                        setrun( pp );
        !           442: 
        !           443:                        /*
        !           444:                         * Enable interrupts.
        !           445:                         * Restart search at start of event queue.
        !           446:                         * Disable interrupts.
        !           447:                         */
        !           448:                        spl( s );
        !           449:                        pp = pp1;
        !           450:                        s = sphi();
        !           451:                }
        !           452:        }
        !           453:        spl(s);
        !           454: }
        !           455: 
        !           456: /*
        !           457:  * Reschedule the processor.
        !           458:  */
        !           459: dispatch()
        !           460: {
        !           461:        register PROC *pp1;
        !           462:        register PROC *pp2;
        !           463:        register unsigned v;
        !           464:        register int s;
        !           465: 
        !           466:        s = sphi();
        !           467:        pp1 = iprocp;
        !           468:        pp2 = &procq;
        !           469:        v = 0;
        !           470:        while ((pp2=pp2->p_lforw) != &procq) {
        !           471:                v -= pp2->p_cval;
        !           472:                if ((pp2->p_flags&PFCORE) == 0)
        !           473:                        continue;
        !           474:                pp1 = pp2->p_lforw;
        !           475:                pp1->p_cval += pp2->p_cval;
        !           476:                pp2->p_cval = v;
        !           477:                pp1->p_lback = pp2->p_lback;
        !           478:                pp1->p_lback->p_lforw = pp1;
        !           479:                pp1 = pp2;
        !           480:                break;
        !           481:        }
        !           482:        spl(s);
        !           483: 
        !           484:        quantum = NCRTICK;
        !           485:        disflag = 0;
        !           486:        if ( pp1 != SELF ) {
        !           487:                /*
        !           488:                 * Consave() returns twice.
        !           489:                 * 1st time is after our context is saved in u.u_syscon,
        !           490:                 *      whereupon we should restore other proc's context.
        !           491:                 * 2nd time is after our context is restored by another proc.
        !           492:                 * Conrest() forces a context switch to a new process.
        !           493:                 */
        !           494:                s = sphi();
        !           495:                SELF = pp1;
        !           496:                if (consave(&u.u_syscon) == 0)
        !           497:                        conrest( FP_SEL(pp1->p_u->s_faddr),
        !           498:                                 offset(uproc,u_syscon) );
        !           499:                if ( SELF->p_pid != 0 )
        !           500:                        segload();
        !           501:                spl(s);
        !           502:        }
        !           503: }
        !           504: 
        !           505: /*
        !           506:  * Add a process to the run queue.
        !           507:  * This routine must be called at high priority.
        !           508:  */
        !           509: setrun(pp1)
        !           510: register PROC *pp1;
        !           511: {
        !           512:        register PROC *pp2;
        !           513:        register unsigned v;
        !           514: 
        !           515:        v = 0;
        !           516:        pp2 = &procq;
        !           517:        for (;;) {
        !           518:                pp2 = pp2->p_lback;
        !           519:                if ((v+=pp2->p_lforw->p_cval) >= pp1->p_cval)
        !           520:                        break;
        !           521:                if (pp2 == &procq)
        !           522:                        break;
        !           523:        }
        !           524:        pp2->p_lforw->p_lback = pp1;
        !           525:        pp1->p_lforw = pp2->p_lforw;
        !           526:        pp2->p_lforw = pp1;
        !           527:        pp1->p_lback = pp2;
        !           528:        v -= pp1->p_cval;
        !           529:        pp1->p_cval = v;
        !           530:        pp1->p_lforw->p_cval -= v;
        !           531:        pp1->p_state = PSRUN;
        !           532: }
        !           533: 
        !           534: /*
        !           535:  * Wait for the gate `g' to unlock, and then lock it.
        !           536:  */
        !           537: lock(g)
        !           538: register GATE g;
        !           539: {
        !           540:        register int s;
        !           541: 
        !           542:        s = sphi();
        !           543:        while (g[0]) {
        !           544:                g[1] = 1;
        !           545:                sleep((char *)g, CVGATE, IVGATE, SVGATE);
        !           546:        }
        !           547:        g[0] = 1;
        !           548:        spl(s);
        !           549: }
        !           550: 
        !           551: /*
        !           552:  * Unlock the gate `g'.
        !           553:  */
        !           554: unlock(g)
        !           555: register GATE g;
        !           556: {
        !           557:        g[0] = 0;
        !           558:        if (g[1]) {
        !           559:                g[1] = 0;
        !           560:                disflag = 1;
        !           561:                wakeup((char *)g);
        !           562:        }
        !           563: }

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