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Annotation of OpenXM_contrib/gc/solaris_threads.c, Revision 1.1.1.1

1.1       maekawa     1: /*
                      2:  * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
                      3:  *
                      4:  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
                      5:  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
                      6:  *
                      7:  * Permission is hereby granted to use or copy this program
                      8:  * for any purpose,  provided the above notices are retained on all copies.
                      9:  * Permission to modify the code and to distribute modified code is granted,
                     10:  * provided the above notices are retained, and a notice that the code was
                     11:  * modified is included with the above copyright notice.
                     12:  */
                     13: /*
                     14:  * Support code for Solaris threads.  Provides functionality we wish Sun
                     15:  * had provided.  Relies on some information we probably shouldn't rely on.
                     16:  */
                     17: /* Boehm, September 14, 1994 4:44 pm PDT */
                     18:
                     19: # if defined(SOLARIS_THREADS)
                     20:
                     21: # include "gc_priv.h"
                     22: # include "solaris_threads.h"
                     23: # include <thread.h>
                     24: # include <synch.h>
                     25: # include <signal.h>
                     26: # include <fcntl.h>
                     27: # include <sys/types.h>
                     28: # include <sys/mman.h>
                     29: # include <sys/time.h>
                     30: # include <sys/resource.h>
                     31: # include <sys/stat.h>
                     32: # include <sys/syscall.h>
                     33: # include <sys/procfs.h>
                     34: # include <sys/lwp.h>
                     35: # include <sys/reg.h>
                     36: # define _CLASSIC_XOPEN_TYPES
                     37: # include <unistd.h>
                     38: # include <errno.h>
                     39:
                     40: /*
                     41:  * This is the default size of the LWP arrays. If there are more LWPs
                     42:  * than this when a stop-the-world GC happens, set_max_lwps will be
                     43:  * called to cope.
                     44:  * This must be higher than the number of LWPs at startup time.
                     45:  * The threads library creates a thread early on, so the min. is 3
                     46:  */
                     47: # define DEFAULT_MAX_LWPS      4
                     48:
                     49: #undef thr_join
                     50: #undef thr_create
                     51: #undef thr_suspend
                     52: #undef thr_continue
                     53:
                     54: cond_t GC_prom_join_cv;                /* Broadcast when any thread terminates */
                     55: cond_t GC_create_cv;           /* Signalled when a new undetached      */
                     56:                                /* thread starts.                       */
                     57:
                     58:
                     59: #ifdef MMAP_STACKS
                     60: static int GC_zfd;
                     61: #endif /* MMAP_STACKS */
                     62:
                     63: /* We use the allocation lock to protect thread-related data structures. */
                     64:
                     65: /* We stop the world using /proc primitives.  This makes some  */
                     66: /* minimal assumptions about the threads implementation.       */
                     67: /* We don't play by the rules, since the rules make this       */
                     68: /* impossible (as of Solaris 2.3).  Also note that as of       */
                     69: /* Solaris 2.3 the various thread and lwp suspension           */
                     70: /* primitives failed to stop threads by the time the request   */
                     71: /* is completed.                                               */
                     72:
                     73:
                     74: static sigset_t old_mask;
                     75:
                     76: /* Sleep for n milliseconds, n < 1000  */
                     77: void GC_msec_sleep(int n)
                     78: {
                     79:     struct timespec ts;
                     80:
                     81:     ts.tv_sec = 0;
                     82:     ts.tv_nsec = 1000000*n;
                     83:     if (syscall(SYS_nanosleep, &ts, 0) < 0) {
                     84:        ABORT("nanosleep failed");
                     85:     }
                     86: }
                     87: /* Turn off preemption;  gross but effective.                  */
                     88: /* Caller has allocation lock.                         */
                     89: /* Actually this is not needed under Solaris 2.3 and   */
                     90: /* 2.4, but hopefully that'll change.                  */
                     91: void preempt_off()
                     92: {
                     93:     sigset_t set;
                     94:
                     95:     (void)sigfillset(&set);
                     96:     sigdelset(&set, SIGABRT);
                     97:     syscall(SYS_sigprocmask, SIG_SETMASK, &set, &old_mask);
                     98: }
                     99:
                    100: void preempt_on()
                    101: {
                    102:     syscall(SYS_sigprocmask, SIG_SETMASK, &old_mask, NULL);
                    103: }
                    104:
                    105: int GC_main_proc_fd = -1;
                    106:
                    107:
                    108: struct lwp_cache_entry {
                    109:     lwpid_t lc_id;
                    110:     int lc_descr;      /* /proc file descriptor.       */
                    111: }  GC_lwp_cache_default[DEFAULT_MAX_LWPS];
                    112:
                    113: static int max_lwps = DEFAULT_MAX_LWPS;
                    114: static struct lwp_cache_entry *GC_lwp_cache = GC_lwp_cache_default;
                    115:
                    116: static prgregset_t GC_lwp_registers_default[DEFAULT_MAX_LWPS];
                    117: static prgregset_t *GC_lwp_registers = GC_lwp_registers_default;
                    118:
                    119: /* Return a file descriptor for the /proc entry corresponding  */
                    120: /* to the given lwp.  The file descriptor may be stale if the  */
                    121: /* lwp exited and a new one was forked.                                */
                    122: static int open_lwp(lwpid_t id)
                    123: {
                    124:     int result;
                    125:     static int next_victim = 0;
                    126:     register int i;
                    127:
                    128:     for (i = 0; i < max_lwps; i++) {
                    129:        if (GC_lwp_cache[i].lc_id == id) return(GC_lwp_cache[i].lc_descr);
                    130:     }
                    131:     result = syscall(SYS_ioctl, GC_main_proc_fd, PIOCOPENLWP, &id);
                    132:     /*
                    133:      * If PIOCOPENLWP fails, try closing fds in the cache until it succeeds.
                    134:      */
                    135:     if (result < 0 && errno == EMFILE) {
                    136:            for (i = 0; i < max_lwps; i++) {
                    137:                if (GC_lwp_cache[i].lc_id != 0) {
                    138:                        (void)syscall(SYS_close, GC_lwp_cache[i].lc_descr);
                    139:                        result = syscall(SYS_ioctl, GC_main_proc_fd, PIOCOPENLWP, &id);
                    140:                        if (result >= 0 || (result < 0 && errno != EMFILE))
                    141:                                break;
                    142:                }
                    143:            }
                    144:     }
                    145:     if (result < 0) {
                    146:        if (errno == EMFILE) {
                    147:                ABORT("Too many open files");
                    148:        }
                    149:         return(-1) /* exited? */;
                    150:     }
                    151:     if (GC_lwp_cache[next_victim].lc_id != 0)
                    152:         (void)syscall(SYS_close, GC_lwp_cache[next_victim].lc_descr);
                    153:     GC_lwp_cache[next_victim].lc_id = id;
                    154:     GC_lwp_cache[next_victim].lc_descr = result;
                    155:     if (++next_victim >= max_lwps)
                    156:        next_victim = 0;
                    157:     return(result);
                    158: }
                    159:
                    160: static void uncache_lwp(lwpid_t id)
                    161: {
                    162:     register int i;
                    163:
                    164:     for (i = 0; i < max_lwps; i++) {
                    165:        if (GC_lwp_cache[i].lc_id == id) {
                    166:            (void)syscall(SYS_close, GC_lwp_cache[id].lc_descr);
                    167:            GC_lwp_cache[i].lc_id = 0;
                    168:            break;
                    169:        }
                    170:     }
                    171: }
                    172:        /* Sequence of current lwp ids  */
                    173: static lwpid_t GC_current_ids_default[DEFAULT_MAX_LWPS + 1];
                    174: static lwpid_t *GC_current_ids = GC_current_ids_default;
                    175:
                    176:        /* Temporary used below (can be big if large number of LWPs) */
                    177: static lwpid_t last_ids_default[DEFAULT_MAX_LWPS + 1];
                    178: static lwpid_t *last_ids = last_ids_default;
                    179:
                    180:
                    181: #define ROUNDUP(n)    WORDS_TO_BYTES(ROUNDED_UP_WORDS(n))
                    182:
                    183: static void set_max_lwps(GC_word n)
                    184: {
                    185:     char *mem;
                    186:     char *oldmem;
                    187:     int required_bytes = ROUNDUP(n * sizeof(struct lwp_cache_entry))
                    188:        + ROUNDUP(n * sizeof(prgregset_t))
                    189:        + ROUNDUP((n + 1) * sizeof(lwpid_t))
                    190:        + ROUNDUP((n + 1) * sizeof(lwpid_t));
                    191:
                    192:     GC_expand_hp_inner(divHBLKSZ((word)required_bytes));
                    193:     oldmem = mem = GC_scratch_alloc(required_bytes);
                    194:     if (0 == mem) ABORT("No space for lwp data structures");
                    195:
                    196:     /*
                    197:      * We can either flush the old lwp cache or copy it over. Do the latter.
                    198:      */
                    199:     memcpy(mem, GC_lwp_cache, max_lwps * sizeof(struct lwp_cache_entry));
                    200:     GC_lwp_cache = (struct lwp_cache_entry*)mem;
                    201:     mem += ROUNDUP(n * sizeof(struct lwp_cache_entry));
                    202:
                    203:     BZERO(GC_lwp_registers, max_lwps * sizeof(GC_lwp_registers[0]));
                    204:     GC_lwp_registers = (prgregset_t *)mem;
                    205:     mem += ROUNDUP(n * sizeof(prgregset_t));
                    206:
                    207:
                    208:     GC_current_ids = (lwpid_t *)mem;
                    209:     mem += ROUNDUP((n + 1) * sizeof(lwpid_t));
                    210:
                    211:     last_ids = (lwpid_t *)mem;
                    212:     mem += ROUNDUP((n + 1)* sizeof(lwpid_t));
                    213:
                    214:     if (mem > oldmem + required_bytes)
                    215:        ABORT("set_max_lwps buffer overflow");
                    216:
                    217:     max_lwps = n;
                    218: }
                    219:
                    220:
                    221: /* Stop all lwps in process.  Assumes preemption is off.       */
                    222: /* Caller has allocation lock (and any other locks he may      */
                    223: /* need).                                                      */
                    224: static void stop_all_lwps()
                    225: {
                    226:     int lwp_fd;
                    227:     char buf[30];
                    228:     prstatus_t status;
                    229:     register int i;
                    230:     GC_bool changed;
                    231:     lwpid_t me = _lwp_self();
                    232:
                    233:     if (GC_main_proc_fd == -1) {
                    234:        sprintf(buf, "/proc/%d", getpid());
                    235:        GC_main_proc_fd = syscall(SYS_open, buf, O_RDONLY);
                    236:         if (GC_main_proc_fd < 0) {
                    237:                if (errno == EMFILE)
                    238:                        ABORT("/proc open failed: too many open files");
                    239:                GC_printf1("/proc open failed: errno %d", errno);
                    240:                abort();
                    241:         }
                    242:     }
                    243:     BZERO(GC_lwp_registers, sizeof (prgregset_t) * max_lwps);
                    244:     for (i = 0; i < max_lwps; i++)
                    245:        last_ids[i] = 0;
                    246:     for (;;) {
                    247:     if (syscall(SYS_ioctl, GC_main_proc_fd, PIOCSTATUS, &status) < 0)
                    248:        ABORT("Main PIOCSTATUS failed");
                    249:        if (status.pr_nlwp < 1)
                    250:                ABORT("Invalid number of lwps returned by PIOCSTATUS");
                    251:        if (status.pr_nlwp >= max_lwps) {
                    252:                set_max_lwps(status.pr_nlwp*2 + 10);
                    253:                /*
                    254:                 * The data in the old GC_current_ids and
                    255:                 * GC_lwp_registers has been trashed. Cleaning out last_ids
                    256:                 * will make sure every LWP gets re-examined.
                    257:                 */
                    258:                for (i = 0; i < max_lwps; i++)
                    259:                        last_ids[i] = 0;
                    260:                continue;
                    261:     }
                    262:         if (syscall(SYS_ioctl, GC_main_proc_fd, PIOCLWPIDS, GC_current_ids) < 0)
                    263:             ABORT("PIOCLWPIDS failed");
                    264:         changed = FALSE;
                    265:         for (i = 0; GC_current_ids[i] != 0 && i < max_lwps; i++) {
                    266:             if (GC_current_ids[i] != last_ids[i]) {
                    267:                 changed = TRUE;
                    268:                 if (GC_current_ids[i] != me) {
                    269:                    /* PIOCSTOP doesn't work without a writable         */
                    270:                    /* descriptor.  And that makes the process          */
                    271:                    /* undebuggable.                                    */
                    272:                     if (_lwp_suspend(GC_current_ids[i]) < 0) {
                    273:                         /* Could happen if the lwp exited */
                    274:                         uncache_lwp(GC_current_ids[i]);
                    275:                         GC_current_ids[i] = me; /* ignore */
                    276:                     }
                    277:                 }
                    278:             }
                    279:         }
                    280:         /*
                    281:          * In the unlikely event something does a fork between the
                    282:         * PIOCSTATUS and the PIOCLWPIDS.
                    283:          */
                    284:         if (i >= max_lwps)
                    285:                continue;
                    286:         /* All lwps in GC_current_ids != me have been suspended.  Note */
                    287:         /* that _lwp_suspend is idempotent.                            */
                    288:         for (i = 0; GC_current_ids[i] != 0; i++) {
                    289:             if (GC_current_ids[i] != last_ids[i]) {
                    290:                 if (GC_current_ids[i] != me) {
                    291:                     lwp_fd = open_lwp(GC_current_ids[i]);
                    292:                    if (lwp_fd == -1)
                    293:                    {
                    294:                            GC_current_ids[i] = me;
                    295:                            continue;
                    296:                    }
                    297:                    /* LWP should be stopped.  Empirically it sometimes */
                    298:                    /* isn't, and more frequently the PR_STOPPED flag   */
                    299:                    /* is not set.  Wait for PR_STOPPED.                */
                    300:                     if (syscall(SYS_ioctl, lwp_fd,
                    301:                                 PIOCSTATUS, &status) < 0) {
                    302:                        /* Possible if the descriptor was stale, or */
                    303:                        /* we encountered the 2.3 _lwp_suspend bug. */
                    304:                        uncache_lwp(GC_current_ids[i]);
                    305:                         GC_current_ids[i] = me; /* handle next time. */
                    306:                     } else {
                    307:                         while (!(status.pr_flags & PR_STOPPED)) {
                    308:                             GC_msec_sleep(1);
                    309:                            if (syscall(SYS_ioctl, lwp_fd,
                    310:                                        PIOCSTATUS, &status) < 0) {
                    311:                                ABORT("Repeated PIOCSTATUS failed");
                    312:                            }
                    313:                            if (status.pr_flags & PR_STOPPED) break;
                    314:
                    315:                            GC_msec_sleep(20);
                    316:                            if (syscall(SYS_ioctl, lwp_fd,
                    317:                                        PIOCSTATUS, &status) < 0) {
                    318:                                ABORT("Repeated PIOCSTATUS failed");
                    319:                            }
                    320:                         }
                    321:                         if (status.pr_who !=  GC_current_ids[i]) {
                    322:                                /* can happen if thread was on death row */
                    323:                                uncache_lwp(GC_current_ids[i]);
                    324:                                GC_current_ids[i] = me; /* handle next time. */
                    325:                                continue;
                    326:                         }
                    327:                         /* Save registers where collector can */
                    328:                        /* find them.                     */
                    329:                            BCOPY(status.pr_reg, GC_lwp_registers[i],
                    330:                                  sizeof (prgregset_t));
                    331:                     }
                    332:                 }
                    333:             }
                    334:         }
                    335:         if (!changed) break;
                    336:         for (i = 0; i < max_lwps; i++) last_ids[i] = GC_current_ids[i];
                    337:     }
                    338: }
                    339:
                    340: /* Restart all lwps in process.  Assumes preemption is off.    */
                    341: static void restart_all_lwps()
                    342: {
                    343:     int lwp_fd;
                    344:     register int i;
                    345:     GC_bool changed;
                    346:     lwpid_t me = _lwp_self();
                    347: #   define PARANOID
                    348:
                    349:     for (i = 0; GC_current_ids[i] != 0; i++) {
                    350: #      ifdef PARANOID
                    351:          if (GC_current_ids[i] != me) {
                    352:            int lwp_fd = open_lwp(GC_current_ids[i]);
                    353:            prstatus_t status;
                    354:
                    355:            if (lwp_fd < 0) ABORT("open_lwp failed");
                    356:            if (syscall(SYS_ioctl, lwp_fd,
                    357:                        PIOCSTATUS, &status) < 0) {
                    358:                 ABORT("PIOCSTATUS failed in restart_all_lwps");
                    359:            }
                    360:            if (memcmp(status.pr_reg, GC_lwp_registers[i],
                    361:                       sizeof (prgregset_t)) != 0) {
                    362:                    int j;
                    363:
                    364:                    for(j = 0; j < NGREG; j++)
                    365:                    {
                    366:                            GC_printf3("%i: %x -> %x\n", j,
                    367:                                       GC_lwp_registers[i][j],
                    368:                                       status.pr_reg[j]);
                    369:                    }
                    370:                ABORT("Register contents changed");
                    371:            }
                    372:            if (!status.pr_flags & PR_STOPPED) {
                    373:                ABORT("lwp no longer stopped");
                    374:            }
                    375: #ifdef SPARC
                    376:            {
                    377:                    gwindows_t windows;
                    378:              if (syscall(SYS_ioctl, lwp_fd,
                    379:                        PIOCGWIN, &windows) < 0) {
                    380:                 ABORT("PIOCSTATUS failed in restart_all_lwps");
                    381:              }
                    382:              if (windows.wbcnt > 0) ABORT("unsaved register windows");
                    383:            }
                    384: #endif
                    385:          }
                    386: #      endif /* PARANOID */
                    387:        if (GC_current_ids[i] == me) continue;
                    388:         if (_lwp_continue(GC_current_ids[i]) < 0) {
                    389:             ABORT("Failed to restart lwp");
                    390:         }
                    391:     }
                    392:     if (i >= max_lwps) ABORT("Too many lwps");
                    393: }
                    394:
                    395: GC_bool GC_multithreaded = 0;
                    396:
                    397: void GC_stop_world()
                    398: {
                    399:     preempt_off();
                    400:     if (GC_multithreaded)
                    401:         stop_all_lwps();
                    402: }
                    403:
                    404: void GC_start_world()
                    405: {
                    406:     if (GC_multithreaded)
                    407:         restart_all_lwps();
                    408:     preempt_on();
                    409: }
                    410:
                    411: void GC_thr_init(void);
                    412:
                    413: GC_bool GC_thr_initialized = FALSE;
                    414:
                    415: size_t GC_min_stack_sz;
                    416:
                    417: size_t GC_page_sz;
                    418:
                    419: /*
                    420:  * stack_head is stored at the top of free stacks
                    421:  */
                    422: struct stack_head {
                    423:        struct stack_head       *next;
                    424:        ptr_t                   base;
                    425:        thread_t                owner;
                    426: };
                    427:
                    428: # define N_FREE_LISTS 25
                    429: struct stack_head *GC_stack_free_lists[N_FREE_LISTS] = { 0 };
                    430:                /* GC_stack_free_lists[i] is free list for stacks of    */
                    431:                /* size GC_min_stack_sz*2**i.                           */
                    432:                /* Free lists are linked through stack_head stored      */                      /* at top of stack.                                     */
                    433:
                    434: /* Return a stack of size at least *stack_size.  *stack_size is        */
                    435: /* replaced by the actual stack size.                          */
                    436: /* Caller holds allocation lock.                               */
                    437: ptr_t GC_stack_alloc(size_t * stack_size)
                    438: {
                    439:     register size_t requested_sz = *stack_size;
                    440:     register size_t search_sz = GC_min_stack_sz;
                    441:     register int index = 0;    /* = log2(search_sz/GC_min_stack_sz) */
                    442:     register ptr_t base;
                    443:     register struct stack_head *result;
                    444:
                    445:     while (search_sz < requested_sz) {
                    446:         search_sz *= 2;
                    447:         index++;
                    448:     }
                    449:     if ((result = GC_stack_free_lists[index]) == 0
                    450:         && (result = GC_stack_free_lists[index+1]) != 0) {
                    451:         /* Try next size up. */
                    452:         search_sz *= 2; index++;
                    453:     }
                    454:     if (result != 0) {
                    455:         base =  GC_stack_free_lists[index]->base;
                    456:         GC_stack_free_lists[index] = GC_stack_free_lists[index]->next;
                    457:     } else {
                    458: #ifdef MMAP_STACKS
                    459:         base = (ptr_t)mmap(0, search_sz + GC_page_sz,
                    460:                             PROT_READ|PROT_WRITE, MAP_PRIVATE |MAP_NORESERVE,
                    461:                             GC_zfd, 0);
                    462:        if (base == (ptr_t)-1)
                    463:        {
                    464:                *stack_size = 0;
                    465:                return NULL;
                    466:        }
                    467:
                    468:        mprotect(base, GC_page_sz, PROT_NONE);
                    469:        /* Should this use divHBLKSZ(search_sz + GC_page_sz) ? -- cf */
                    470:        GC_is_fresh((struct hblk *)base, divHBLKSZ(search_sz));
                    471:        base += GC_page_sz;
                    472:
                    473: #else
                    474:         base = (ptr_t) GC_scratch_alloc(search_sz + 2*GC_page_sz);
                    475:        if (base == NULL)
                    476:        {
                    477:                *stack_size = 0;
                    478:                return NULL;
                    479:        }
                    480:
                    481:         base = (ptr_t)(((word)base + GC_page_sz) & ~(GC_page_sz - 1));
                    482:         /* Protect hottest page to detect overflow. */
                    483: #      ifdef SOLARIS23_MPROTECT_BUG_FIXED
                    484:             mprotect(base, GC_page_sz, PROT_NONE);
                    485: #      endif
                    486:         GC_is_fresh((struct hblk *)base, divHBLKSZ(search_sz));
                    487:
                    488:         base += GC_page_sz;
                    489: #endif
                    490:     }
                    491:     *stack_size = search_sz;
                    492:     return(base);
                    493: }
                    494:
                    495: /* Caller holds  allocationlock.                                       */
                    496: void GC_stack_free(ptr_t stack, size_t size)
                    497: {
                    498:     register int index = 0;
                    499:     register size_t search_sz = GC_min_stack_sz;
                    500:     register struct stack_head *head;
                    501:
                    502: #ifdef MMAP_STACKS
                    503:     /* Zero pointers */
                    504:     mmap(stack, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_NORESERVE|MAP_FIXED,
                    505:         GC_zfd, 0);
                    506: #endif
                    507:     while (search_sz < size) {
                    508:         search_sz *= 2;
                    509:         index++;
                    510:     }
                    511:     if (search_sz != size) ABORT("Bad stack size");
                    512:
                    513:     head = (struct stack_head *)(stack + search_sz - sizeof(struct stack_head));
                    514:     head->next = GC_stack_free_lists[index];
                    515:     head->base = stack;
                    516:     GC_stack_free_lists[index] = head;
                    517: }
                    518:
                    519: void GC_my_stack_limits();
                    520:
                    521: /* Notify virtual dirty bit implementation that known empty parts of   */
                    522: /* stacks do not contain useful data.                                  */
                    523: /* Caller holds allocation lock.                                       */
                    524: void GC_old_stacks_are_fresh()
                    525: {
                    526: /* No point in doing this for MMAP stacks - and pointers are zero'd out */
                    527: /* by the mmap in GC_stack_free */
                    528: #ifndef MMAP_STACKS
                    529:     register int i;
                    530:     register struct stack_head *s;
                    531:     register ptr_t p;
                    532:     register size_t sz;
                    533:     register struct hblk * h;
                    534:     int dummy;
                    535:
                    536:     for (i = 0, sz= GC_min_stack_sz; i < N_FREE_LISTS;
                    537:          i++, sz *= 2) {
                    538:          for (s = GC_stack_free_lists[i]; s != 0; s = s->next) {
                    539:              p = s->base;
                    540:              h = (struct hblk *)(((word)p + HBLKSIZE-1) & ~(HBLKSIZE-1));
                    541:              if ((ptr_t)h == p) {
                    542:                  GC_is_fresh((struct hblk *)p, divHBLKSZ(sz));
                    543:              } else {
                    544:                  GC_is_fresh((struct hblk *)p, divHBLKSZ(sz) - 1);
                    545:                  BZERO(p, (ptr_t)h - p);
                    546:              }
                    547:          }
                    548:     }
                    549: #endif /* MMAP_STACKS */
                    550:     GC_my_stack_limits();
                    551: }
                    552:
                    553: /* The set of all known threads.  We intercept thread creation and     */
                    554: /* joins.  We never actually create detached threads.  We allocate all         */
                    555: /* new thread stacks ourselves.  These allow us to maintain this       */
                    556: /* data structure.                                                     */
                    557:
                    558: # define THREAD_TABLE_SZ 128   /* Must be power of 2   */
                    559: volatile GC_thread GC_threads[THREAD_TABLE_SZ];
                    560:
                    561: /* Add a thread to GC_threads.  We assume it wasn't already there.     */
                    562: /* Caller holds allocation lock.                                       */
                    563: GC_thread GC_new_thread(thread_t id)
                    564: {
                    565:     int hv = ((word)id) % THREAD_TABLE_SZ;
                    566:     GC_thread result;
                    567:     static struct GC_Thread_Rep first_thread;
                    568:     static GC_bool first_thread_used = FALSE;
                    569:
                    570:     if (!first_thread_used) {
                    571:        result = &first_thread;
                    572:        first_thread_used = TRUE;
                    573:        /* Dont acquire allocation lock, since we may already hold it. */
                    574:     } else {
                    575:         result = (struct GC_Thread_Rep *)
                    576:                 GC_generic_malloc_inner(sizeof(struct GC_Thread_Rep), NORMAL);
                    577:     }
                    578:     if (result == 0) return(0);
                    579:     result -> id = id;
                    580:     result -> next = GC_threads[hv];
                    581:     GC_threads[hv] = result;
                    582:     /* result -> finished = 0; */
                    583:     (void) cond_init(&(result->join_cv), USYNC_THREAD, 0);
                    584:     return(result);
                    585: }
                    586:
                    587: /* Delete a thread from GC_threads.  We assume it is there.    */
                    588: /* (The code intentionally traps if it wasn't.)                        */
                    589: /* Caller holds allocation lock.                               */
                    590: void GC_delete_thread(thread_t id)
                    591: {
                    592:     int hv = ((word)id) % THREAD_TABLE_SZ;
                    593:     register GC_thread p = GC_threads[hv];
                    594:     register GC_thread prev = 0;
                    595:
                    596:     while (p -> id != id) {
                    597:         prev = p;
                    598:         p = p -> next;
                    599:     }
                    600:     if (prev == 0) {
                    601:         GC_threads[hv] = p -> next;
                    602:     } else {
                    603:         prev -> next = p -> next;
                    604:     }
                    605: }
                    606:
                    607: /* Return the GC_thread correpsonding to a given thread_t.     */
                    608: /* Returns 0 if it's not there.                                        */
                    609: /* Caller holds  allocation lock.                              */
                    610: GC_thread GC_lookup_thread(thread_t id)
                    611: {
                    612:     int hv = ((word)id) % THREAD_TABLE_SZ;
                    613:     register GC_thread p = GC_threads[hv];
                    614:
                    615:     while (p != 0 && p -> id != id) p = p -> next;
                    616:     return(p);
                    617: }
                    618:
                    619: /* Notify dirty bit implementation of unused parts of my stack. */
                    620: /* Caller holds allocation lock.                               */
                    621: void GC_my_stack_limits()
                    622: {
                    623:     int dummy;
                    624:     register ptr_t hottest = (ptr_t)((word)(&dummy) & ~(HBLKSIZE-1));
                    625:     register GC_thread me = GC_lookup_thread(thr_self());
                    626:     register size_t stack_size = me -> stack_size;
                    627:     register ptr_t stack;
                    628:
                    629:     if (stack_size == 0) {
                    630:       /* original thread */
                    631:         struct rlimit rl;
                    632:
                    633:         if (getrlimit(RLIMIT_STACK, &rl) != 0) ABORT("getrlimit failed");
                    634:         /* Empirically, what should be the stack page with lowest      */
                    635:         /* address is actually inaccessible.                           */
                    636:         stack_size = ((word)rl.rlim_cur & ~(HBLKSIZE-1)) - GC_page_sz;
                    637:         stack = GC_stackbottom - stack_size + GC_page_sz;
                    638:     } else {
                    639:         stack = me -> stack;
                    640:     }
                    641:     if (stack > hottest || stack + stack_size < hottest) {
                    642:        ABORT("sp out of bounds");
                    643:     }
                    644:     GC_is_fresh((struct hblk *)stack, divHBLKSZ(hottest - stack));
                    645: }
                    646:
                    647:
                    648: /* We hold allocation lock.  We assume the world is stopped.   */
                    649: void GC_push_all_stacks()
                    650: {
                    651:     register int i;
                    652:     register GC_thread p;
                    653:     register ptr_t sp = GC_approx_sp();
                    654:     register ptr_t bottom, top;
                    655:     struct rlimit rl;
                    656:
                    657: #   define PUSH(bottom,top) \
                    658:       if (GC_dirty_maintained) { \
                    659:        GC_push_dirty((bottom), (top), GC_page_was_ever_dirty, \
                    660:                      GC_push_all_stack); \
                    661:       } else { \
                    662:         GC_push_all_stack((bottom), (top)); \
                    663:       }
                    664:     GC_push_all_stack((ptr_t)GC_lwp_registers,
                    665:                      (ptr_t)GC_lwp_registers
                    666:                      + max_lwps * sizeof(GC_lwp_registers[0]));
                    667:     for (i = 0; i < THREAD_TABLE_SZ; i++) {
                    668:       for (p = GC_threads[i]; p != 0; p = p -> next) {
                    669:         if (p -> stack_size != 0) {
                    670:             bottom = p -> stack;
                    671:             top = p -> stack + p -> stack_size;
                    672:         } else {
                    673:             /* The original stack. */
                    674:             if (getrlimit(RLIMIT_STACK, &rl) != 0) ABORT("getrlimit failed");
                    675:             bottom = GC_stackbottom - rl.rlim_cur + GC_page_sz;
                    676:             top = GC_stackbottom;
                    677:         }
                    678:         if ((word)sp > (word)bottom && (word)sp < (word)top) bottom = sp;
                    679:         PUSH(bottom, top);
                    680:       }
                    681:     }
                    682: }
                    683:
                    684:
                    685: int GC_is_thread_stack(ptr_t addr)
                    686: {
                    687:     register int i;
                    688:     register GC_thread p;
                    689:     register ptr_t bottom, top;
                    690:     struct rlimit rl;
                    691:
                    692:     for (i = 0; i < THREAD_TABLE_SZ; i++) {
                    693:       for (p = GC_threads[i]; p != 0; p = p -> next) {
                    694:         if (p -> stack_size != 0) {
                    695:             if (p -> stack <= addr &&
                    696:                addr < p -> stack + p -> stack_size)
                    697:                    return 1;
                    698:        }
                    699:       }
                    700:     }
                    701: }
                    702:
                    703: /* The only thread that ever really performs a thr_join.       */
                    704: void * GC_thr_daemon(void * dummy)
                    705: {
                    706:     void *status;
                    707:     thread_t departed;
                    708:     register GC_thread t;
                    709:     register int i;
                    710:     register int result;
                    711:
                    712:     for(;;) {
                    713:       start:
                    714:         result = thr_join((thread_t)0, &departed, &status);
                    715:        LOCK();
                    716:        if (result != 0) {
                    717:            /* No more threads; wait for create. */
                    718:            for (i = 0; i < THREAD_TABLE_SZ; i++) {
                    719:                for (t = GC_threads[i]; t != 0; t = t -> next) {
                    720:                     if (!(t -> flags & (DETACHED | FINISHED))) {
                    721:                       UNLOCK();
                    722:                       goto start; /* Thread started just before we */
                    723:                                  /* acquired the lock.            */
                    724:                     }
                    725:                 }
                    726:             }
                    727:             cond_wait(&GC_create_cv, &GC_allocate_ml);
                    728:             UNLOCK();
                    729:        } else {
                    730:            t = GC_lookup_thread(departed);
                    731:            GC_multithreaded--;
                    732:            if (!(t -> flags & CLIENT_OWNS_STACK)) {
                    733:                GC_stack_free(t -> stack, t -> stack_size);
                    734:            }
                    735:            if (t -> flags & DETACHED) {
                    736:                GC_delete_thread(departed);
                    737:            } else {
                    738:                t -> status = status;
                    739:                t -> flags |= FINISHED;
                    740:                cond_signal(&(t -> join_cv));
                    741:                cond_broadcast(&GC_prom_join_cv);
                    742:            }
                    743:            UNLOCK();
                    744:        }
                    745:     }
                    746: }
                    747:
                    748: /* We hold the allocation lock, or caller ensures that 2 instances     */
                    749: /* cannot be invoked concurrently.                                     */
                    750: void GC_thr_init(void)
                    751: {
                    752:     GC_thread t;
                    753:     thread_t tid;
                    754:
                    755:     if (GC_thr_initialized)
                    756:            return;
                    757:     GC_thr_initialized = TRUE;
                    758:     GC_min_stack_sz = ((thr_min_stack() + 32*1024 + HBLKSIZE-1)
                    759:                       & ~(HBLKSIZE - 1));
                    760:     GC_page_sz = sysconf(_SC_PAGESIZE);
                    761: #ifdef MMAP_STACKS
                    762:     GC_zfd = open("/dev/zero", O_RDONLY);
                    763:     if (GC_zfd == -1)
                    764:            ABORT("Can't open /dev/zero");
                    765: #endif /* MMAP_STACKS */
                    766:     cond_init(&GC_prom_join_cv, USYNC_THREAD, 0);
                    767:     cond_init(&GC_create_cv, USYNC_THREAD, 0);
                    768:     /* Add the initial thread, so we can stop it.      */
                    769:       t = GC_new_thread(thr_self());
                    770:       t -> stack_size = 0;
                    771:       t -> flags = DETACHED | CLIENT_OWNS_STACK;
                    772:     if (thr_create(0 /* stack */, 0 /* stack_size */, GC_thr_daemon,
                    773:                   0 /* arg */, THR_DETACHED | THR_DAEMON,
                    774:                   &tid /* thread_id */) != 0) {
                    775:        ABORT("Cant fork daemon");
                    776:     }
                    777:     thr_setprio(tid, 126);
                    778: }
                    779:
                    780: /* We acquire the allocation lock to prevent races with        */
                    781: /* stopping/starting world.                                    */
                    782: /* This is no more correct than the underlying Solaris 2.X     */
                    783: /* implementation.  Under 2.3 THIS IS BROKEN.                  */
                    784: int GC_thr_suspend(thread_t target_thread)
                    785: {
                    786:     GC_thread t;
                    787:     int result;
                    788:
                    789:     LOCK();
                    790:     result = thr_suspend(target_thread);
                    791:     if (result == 0) {
                    792:        t = GC_lookup_thread(target_thread);
                    793:        if (t == 0) ABORT("thread unknown to GC");
                    794:         t -> flags |= SUSPENDED;
                    795:     }
                    796:     UNLOCK();
                    797:     return(result);
                    798: }
                    799:
                    800: int GC_thr_continue(thread_t target_thread)
                    801: {
                    802:     GC_thread t;
                    803:     int result;
                    804:
                    805:     LOCK();
                    806:     result = thr_continue(target_thread);
                    807:     if (result == 0) {
                    808:        t = GC_lookup_thread(target_thread);
                    809:        if (t == 0) ABORT("thread unknown to GC");
                    810:         t -> flags &= ~SUSPENDED;
                    811:     }
                    812:     UNLOCK();
                    813:     return(result);
                    814: }
                    815:
                    816: int GC_thr_join(thread_t wait_for, thread_t *departed, void **status)
                    817: {
                    818:     register GC_thread t;
                    819:     int result = 0;
                    820:
                    821:     LOCK();
                    822:     if (wait_for == 0) {
                    823:         register int i;
                    824:         register GC_bool thread_exists;
                    825:
                    826:        for (;;) {
                    827:          thread_exists = FALSE;
                    828:          for (i = 0; i < THREAD_TABLE_SZ; i++) {
                    829:            for (t = GC_threads[i]; t != 0; t = t -> next) {
                    830:               if (!(t -> flags & DETACHED)) {
                    831:                 if (t -> flags & FINISHED) {
                    832:                   goto found;
                    833:                 }
                    834:                 thread_exists = TRUE;
                    835:               }
                    836:             }
                    837:           }
                    838:           if (!thread_exists) {
                    839:               result = ESRCH;
                    840:              goto out;
                    841:           }
                    842:           cond_wait(&GC_prom_join_cv, &GC_allocate_ml);
                    843:         }
                    844:     } else {
                    845:         t = GC_lookup_thread(wait_for);
                    846:        if (t == 0 || t -> flags & DETACHED) {
                    847:            result = ESRCH;
                    848:            goto out;
                    849:        }
                    850:        if (wait_for == thr_self()) {
                    851:            result = EDEADLK;
                    852:            goto out;
                    853:        }
                    854:        while (!(t -> flags & FINISHED)) {
                    855:             cond_wait(&(t -> join_cv), &GC_allocate_ml);
                    856:        }
                    857:
                    858:     }
                    859:   found:
                    860:     if (status) *status = t -> status;
                    861:     if (departed) *departed = t -> id;
                    862:     cond_destroy(&(t -> join_cv));
                    863:     GC_delete_thread(t -> id);
                    864:   out:
                    865:     UNLOCK();
                    866:     return(result);
                    867: }
                    868:
                    869:
                    870: int
                    871: GC_thr_create(void *stack_base, size_t stack_size,
                    872:               void *(*start_routine)(void *), void *arg, long flags,
                    873:               thread_t *new_thread)
                    874: {
                    875:     int result;
                    876:     GC_thread t;
                    877:     thread_t my_new_thread;
                    878:     word my_flags = 0;
                    879:     void * stack = stack_base;
                    880:
                    881:     LOCK();
                    882:     if (!GC_thr_initialized)
                    883:     {
                    884:     GC_thr_init();
                    885:     }
                    886:     GC_multithreaded++;
                    887:     if (stack == 0) {
                    888:        if (stack_size == 0) stack_size = GC_min_stack_sz;
                    889:        stack = (void *)GC_stack_alloc(&stack_size);
                    890:        if (stack == 0) {
                    891:            GC_multithreaded--;
                    892:            UNLOCK();
                    893:            return(ENOMEM);
                    894:        }
                    895:     } else {
                    896:        my_flags |= CLIENT_OWNS_STACK;
                    897:     }
                    898:     if (flags & THR_DETACHED) my_flags |= DETACHED;
                    899:     if (flags & THR_SUSPENDED) my_flags |= SUSPENDED;
                    900:     result = thr_create(stack, stack_size, start_routine,
                    901:                        arg, flags & ~THR_DETACHED, &my_new_thread);
                    902:     if (result == 0) {
                    903:         t = GC_new_thread(my_new_thread);
                    904:         t -> flags = my_flags;
                    905:         if (!(my_flags & DETACHED)) cond_init(&(t -> join_cv), USYNC_THREAD, 0);
                    906:         t -> stack = stack;
                    907:         t -> stack_size = stack_size;
                    908:         if (new_thread != 0) *new_thread = my_new_thread;
                    909:         cond_signal(&GC_create_cv);
                    910:     } else {
                    911:        GC_multithreaded--;
                    912:         if (!(my_flags & CLIENT_OWNS_STACK)) {
                    913:            GC_stack_free(stack, stack_size);
                    914:        }
                    915:     }
                    916:     UNLOCK();
                    917:     return(result);
                    918: }
                    919:
                    920: # else /* SOLARIS_THREADS */
                    921:
                    922: #ifndef LINT
                    923:   int GC_no_sunOS_threads;
                    924: #endif
                    925: #endif

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