root/gc/solaris_threads.c
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DEFINITIONS
This source file includes following definitions.
- GC_msec_sleep
- preempt_off
- preempt_on
- open_lwp
- uncache_lwp
- set_max_lwps
- stop_all_lwps
- restart_all_lwps
- GC_stop_world
- GC_start_world
- GC_stack_alloc
- GC_stack_free
- GC_old_stacks_are_fresh
- GC_PROTO
- GC_new_thread
- GC_delete_thread
- GC_lookup_thread
- GC_get_orig_stack_size
- GC_my_stack_limits
- GC_push_all_stacks
- GC_is_thread_stack
- GC_thr_daemon
- GC_thr_init
- GC_thr_suspend
- GC_thr_continue
- GC_thr_join
- GC_thr_create
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 # include "private/gc_priv.h"
20
21 # if defined(GC_SOLARIS_THREADS) || defined(GC_SOLARIS_PTHREADS)
22 # include "private/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 #ifdef HANDLE_FORK
41 --> Not yet supported. Try porting the code from linux_threads.c.
42 #endif
43
44 /*
45 * This is the default size of the LWP arrays. If there are more LWPs
46 * than this when a stop-the-world GC happens, set_max_lwps will be
47 * called to cope.
48 * This must be higher than the number of LWPs at startup time.
49 * The threads library creates a thread early on, so the min. is 3
50 */
51 # define DEFAULT_MAX_LWPS 4
52
53 #undef thr_join
54 #undef thr_create
55 #undef thr_suspend
56 #undef thr_continue
57
58 cond_t GC_prom_join_cv; /* Broadcast when any thread terminates */
59 cond_t GC_create_cv; /* Signalled when a new undetached */
60 /* thread starts. */
61
62
63 #ifdef MMAP_STACKS
64 static int GC_zfd;
65 #endif /* MMAP_STACKS */
66
67 /* We use the allocation lock to protect thread-related data structures. */
68
69 /* We stop the world using /proc primitives. This makes some */
70 /* minimal assumptions about the threads implementation. */
71 /* We don't play by the rules, since the rules make this */
72 /* impossible (as of Solaris 2.3). Also note that as of */
73 /* Solaris 2.3 the various thread and lwp suspension */
74 /* primitives failed to stop threads by the time the request */
75 /* is completed. */
76
77
78 static sigset_t old_mask;
79
80 /* Sleep for n milliseconds, n < 1000 */
81 void GC_msec_sleep(int n)
82 {
83 struct timespec ts;
84
85 ts.tv_sec = 0;
86 ts.tv_nsec = 1000000*n;
87 if (syscall(SYS_nanosleep, &ts, 0) < 0) {
88 ABORT("nanosleep failed");
89 }
90 }
91 /* Turn off preemption; gross but effective. */
92 /* Caller has allocation lock. */
93 /* Actually this is not needed under Solaris 2.3 and */
94 /* 2.4, but hopefully that'll change. */
95 void preempt_off()
96 {
97 sigset_t set;
98
99 (void)sigfillset(&set);
100 sigdelset(&set, SIGABRT);
101 syscall(SYS_sigprocmask, SIG_SETMASK, &set, &old_mask);
102 }
103
104 void preempt_on()
105 {
106 syscall(SYS_sigprocmask, SIG_SETMASK, &old_mask, NULL);
107 }
108
109 int GC_main_proc_fd = -1;
110
111
112 struct lwp_cache_entry {
113 lwpid_t lc_id;
114 int lc_descr; /* /proc file descriptor. */
115 } GC_lwp_cache_default[DEFAULT_MAX_LWPS];
116
117 static int max_lwps = DEFAULT_MAX_LWPS;
118 static struct lwp_cache_entry *GC_lwp_cache = GC_lwp_cache_default;
119
120 static prgregset_t GC_lwp_registers_default[DEFAULT_MAX_LWPS];
121 static prgregset_t *GC_lwp_registers = GC_lwp_registers_default;
122
123 /* Return a file descriptor for the /proc entry corresponding */
124 /* to the given lwp. The file descriptor may be stale if the */
125 /* lwp exited and a new one was forked. */
126 static int open_lwp(lwpid_t id)
127 {
128 int result;
129 static int next_victim = 0;
130 register int i;
131
132 for (i = 0; i < max_lwps; i++) {
133 if (GC_lwp_cache[i].lc_id == id) return(GC_lwp_cache[i].lc_descr);
134 }
135 result = syscall(SYS_ioctl, GC_main_proc_fd, PIOCOPENLWP, &id);
136 /*
137 * If PIOCOPENLWP fails, try closing fds in the cache until it succeeds.
138 */
139 if (result < 0 && errno == EMFILE) {
140 for (i = 0; i < max_lwps; i++) {
141 if (GC_lwp_cache[i].lc_id != 0) {
142 (void)syscall(SYS_close, GC_lwp_cache[i].lc_descr);
143 result = syscall(SYS_ioctl, GC_main_proc_fd, PIOCOPENLWP, &id);
144 if (result >= 0 || (result < 0 && errno != EMFILE))
145 break;
146 }
147 }
148 }
149 if (result < 0) {
150 if (errno == EMFILE) {
151 ABORT("Too many open files");
152 }
153 return(-1) /* exited? */;
154 }
155 if (GC_lwp_cache[next_victim].lc_id != 0)
156 (void)syscall(SYS_close, GC_lwp_cache[next_victim].lc_descr);
157 GC_lwp_cache[next_victim].lc_id = id;
158 GC_lwp_cache[next_victim].lc_descr = result;
159 if (++next_victim >= max_lwps)
160 next_victim = 0;
161 return(result);
162 }
163
164 static void uncache_lwp(lwpid_t id)
165 {
166 register int i;
167
168 for (i = 0; i < max_lwps; i++) {
169 if (GC_lwp_cache[i].lc_id == id) {
170 (void)syscall(SYS_close, GC_lwp_cache[id].lc_descr);
171 GC_lwp_cache[i].lc_id = 0;
172 break;
173 }
174 }
175 }
176 /* Sequence of current lwp ids */
177 static lwpid_t GC_current_ids_default[DEFAULT_MAX_LWPS + 1];
178 static lwpid_t *GC_current_ids = GC_current_ids_default;
179
180 /* Temporary used below (can be big if large number of LWPs) */
181 static lwpid_t last_ids_default[DEFAULT_MAX_LWPS + 1];
182 static lwpid_t *last_ids = last_ids_default;
183
184
185 #define ROUNDUP(n) WORDS_TO_BYTES(ROUNDED_UP_WORDS(n))
186
187 static void set_max_lwps(GC_word n)
188 {
189 char *mem;
190 char *oldmem;
191 int required_bytes = ROUNDUP(n * sizeof(struct lwp_cache_entry))
192 + ROUNDUP(n * sizeof(prgregset_t))
193 + ROUNDUP((n + 1) * sizeof(lwpid_t))
194 + ROUNDUP((n + 1) * sizeof(lwpid_t));
195
196 GC_expand_hp_inner(divHBLKSZ((word)required_bytes));
197 oldmem = mem = GC_scratch_alloc(required_bytes);
198 if (0 == mem) ABORT("No space for lwp data structures");
199
200 /*
201 * We can either flush the old lwp cache or copy it over. Do the latter.
202 */
203 memcpy(mem, GC_lwp_cache, max_lwps * sizeof(struct lwp_cache_entry));
204 GC_lwp_cache = (struct lwp_cache_entry*)mem;
205 mem += ROUNDUP(n * sizeof(struct lwp_cache_entry));
206
207 BZERO(GC_lwp_registers, max_lwps * sizeof(GC_lwp_registers[0]));
208 GC_lwp_registers = (prgregset_t *)mem;
209 mem += ROUNDUP(n * sizeof(prgregset_t));
210
211
212 GC_current_ids = (lwpid_t *)mem;
213 mem += ROUNDUP((n + 1) * sizeof(lwpid_t));
214
215 last_ids = (lwpid_t *)mem;
216 mem += ROUNDUP((n + 1)* sizeof(lwpid_t));
217
218 if (mem > oldmem + required_bytes)
219 ABORT("set_max_lwps buffer overflow");
220
221 max_lwps = n;
222 }
223
224
225 /* Stop all lwps in process. Assumes preemption is off. */
226 /* Caller has allocation lock (and any other locks he may */
227 /* need). */
228 static void stop_all_lwps()
229 {
230 int lwp_fd;
231 char buf[30];
232 prstatus_t status;
233 register int i;
234 GC_bool changed;
235 lwpid_t me = _lwp_self();
236
237 if (GC_main_proc_fd == -1) {
238 sprintf(buf, "/proc/%d", getpid());
239 GC_main_proc_fd = syscall(SYS_open, buf, O_RDONLY);
240 if (GC_main_proc_fd < 0) {
241 if (errno == EMFILE)
242 ABORT("/proc open failed: too many open files");
243 GC_printf1("/proc open failed: errno %d", errno);
244 abort();
245 }
246 }
247 BZERO(GC_lwp_registers, sizeof (prgregset_t) * max_lwps);
248 for (i = 0; i < max_lwps; i++)
249 last_ids[i] = 0;
250 for (;;) {
251 if (syscall(SYS_ioctl, GC_main_proc_fd, PIOCSTATUS, &status) < 0)
252 ABORT("Main PIOCSTATUS failed");
253 if (status.pr_nlwp < 1)
254 ABORT("Invalid number of lwps returned by PIOCSTATUS");
255 if (status.pr_nlwp >= max_lwps) {
256 set_max_lwps(status.pr_nlwp*2 + 10);
257 /*
258 * The data in the old GC_current_ids and
259 * GC_lwp_registers has been trashed. Cleaning out last_ids
260 * will make sure every LWP gets re-examined.
261 */
262 for (i = 0; i < max_lwps; i++)
263 last_ids[i] = 0;
264 continue;
265 }
266 if (syscall(SYS_ioctl, GC_main_proc_fd, PIOCLWPIDS, GC_current_ids) < 0)
267 ABORT("PIOCLWPIDS failed");
268 changed = FALSE;
269 for (i = 0; GC_current_ids[i] != 0 && i < max_lwps; i++) {
270 if (GC_current_ids[i] != last_ids[i]) {
271 changed = TRUE;
272 if (GC_current_ids[i] != me) {
273 /* PIOCSTOP doesn't work without a writable */
274 /* descriptor. And that makes the process */
275 /* undebuggable. */
276 if (_lwp_suspend(GC_current_ids[i]) < 0) {
277 /* Could happen if the lwp exited */
278 uncache_lwp(GC_current_ids[i]);
279 GC_current_ids[i] = me; /* ignore */
280 }
281 }
282 }
283 }
284 /*
285 * In the unlikely event something does a fork between the
286 * PIOCSTATUS and the PIOCLWPIDS.
287 */
288 if (i >= max_lwps)
289 continue;
290 /* All lwps in GC_current_ids != me have been suspended. Note */
291 /* that _lwp_suspend is idempotent. */
292 for (i = 0; GC_current_ids[i] != 0; i++) {
293 if (GC_current_ids[i] != last_ids[i]) {
294 if (GC_current_ids[i] != me) {
295 lwp_fd = open_lwp(GC_current_ids[i]);
296 if (lwp_fd == -1)
297 {
298 GC_current_ids[i] = me;
299 continue;
300 }
301 /* LWP should be stopped. Empirically it sometimes */
302 /* isn't, and more frequently the PR_STOPPED flag */
303 /* is not set. Wait for PR_STOPPED. */
304 if (syscall(SYS_ioctl, lwp_fd,
305 PIOCSTATUS, &status) < 0) {
306 /* Possible if the descriptor was stale, or */
307 /* we encountered the 2.3 _lwp_suspend bug. */
308 uncache_lwp(GC_current_ids[i]);
309 GC_current_ids[i] = me; /* handle next time. */
310 } else {
311 while (!(status.pr_flags & PR_STOPPED)) {
312 GC_msec_sleep(1);
313 if (syscall(SYS_ioctl, lwp_fd,
314 PIOCSTATUS, &status) < 0) {
315 ABORT("Repeated PIOCSTATUS failed");
316 }
317 if (status.pr_flags & PR_STOPPED) break;
318
319 GC_msec_sleep(20);
320 if (syscall(SYS_ioctl, lwp_fd,
321 PIOCSTATUS, &status) < 0) {
322 ABORT("Repeated PIOCSTATUS failed");
323 }
324 }
325 if (status.pr_who != GC_current_ids[i]) {
326 /* can happen if thread was on death row */
327 uncache_lwp(GC_current_ids[i]);
328 GC_current_ids[i] = me; /* handle next time. */
329 continue;
330 }
331 /* Save registers where collector can */
332 /* find them. */
333 BCOPY(status.pr_reg, GC_lwp_registers[i],
334 sizeof (prgregset_t));
335 }
336 }
337 }
338 }
339 if (!changed) break;
340 for (i = 0; i < max_lwps; i++) last_ids[i] = GC_current_ids[i];
341 }
342 }
343
344 /* Restart all lwps in process. Assumes preemption is off. */
345 static void restart_all_lwps()
346 {
347 int lwp_fd;
348 register int i;
349 GC_bool changed;
350 lwpid_t me = _lwp_self();
351 # define PARANOID
352
353 for (i = 0; GC_current_ids[i] != 0; i++) {
354 # ifdef PARANOID
355 if (GC_current_ids[i] != me) {
356 int lwp_fd = open_lwp(GC_current_ids[i]);
357 prstatus_t status;
358
359 if (lwp_fd < 0) ABORT("open_lwp failed");
360 if (syscall(SYS_ioctl, lwp_fd,
361 PIOCSTATUS, &status) < 0) {
362 ABORT("PIOCSTATUS failed in restart_all_lwps");
363 }
364 if (memcmp(status.pr_reg, GC_lwp_registers[i],
365 sizeof (prgregset_t)) != 0) {
366 int j;
367
368 for(j = 0; j < NPRGREG; j++)
369 {
370 GC_printf3("%i: %x -> %x\n", j,
371 GC_lwp_registers[i][j],
372 status.pr_reg[j]);
373 }
374 ABORT("Register contents changed");
375 }
376 if (!status.pr_flags & PR_STOPPED) {
377 ABORT("lwp no longer stopped");
378 }
379 #ifdef SPARC
380 {
381 gwindows_t windows;
382 if (syscall(SYS_ioctl, lwp_fd,
383 PIOCGWIN, &windows) < 0) {
384 ABORT("PIOCSTATUS failed in restart_all_lwps");
385 }
386 if (windows.wbcnt > 0) ABORT("unsaved register windows");
387 }
388 #endif
389 }
390 # endif /* PARANOID */
391 if (GC_current_ids[i] == me) continue;
392 if (_lwp_continue(GC_current_ids[i]) < 0) {
393 ABORT("Failed to restart lwp");
394 }
395 }
396 if (i >= max_lwps) ABORT("Too many lwps");
397 }
398
399 GC_bool GC_multithreaded = 0;
400
401 void GC_stop_world()
402 {
403 preempt_off();
404 if (GC_multithreaded)
405 stop_all_lwps();
406 }
407
408 void GC_start_world()
409 {
410 if (GC_multithreaded)
411 restart_all_lwps();
412 preempt_on();
413 }
414
415 void GC_thr_init(void);
416
417 GC_bool GC_thr_initialized = FALSE;
418
419 size_t GC_min_stack_sz;
420
421
422 /*
423 * stack_head is stored at the top of free stacks
424 */
425 struct stack_head {
426 struct stack_head *next;
427 ptr_t base;
428 thread_t owner;
429 };
430
431 # define N_FREE_LISTS 25
432 struct stack_head *GC_stack_free_lists[N_FREE_LISTS] = { 0 };
433 /* GC_stack_free_lists[i] is free list for stacks of */
434 /* size GC_min_stack_sz*2**i. */
435 /* Free lists are linked through stack_head stored */ /* at top of stack. */
436
437 /* Return a stack of size at least *stack_size. *stack_size is */
438 /* replaced by the actual stack size. */
439 /* Caller holds allocation lock. */
440 ptr_t GC_stack_alloc(size_t * stack_size)
441 {
442 register size_t requested_sz = *stack_size;
443 register size_t search_sz = GC_min_stack_sz;
444 register int index = 0; /* = log2(search_sz/GC_min_stack_sz) */
445 register ptr_t base;
446 register struct stack_head *result;
447
448 while (search_sz < requested_sz) {
449 search_sz *= 2;
450 index++;
451 }
452 if ((result = GC_stack_free_lists[index]) == 0
453 && (result = GC_stack_free_lists[index+1]) != 0) {
454 /* Try next size up. */
455 search_sz *= 2; index++;
456 }
457 if (result != 0) {
458 base = GC_stack_free_lists[index]->base;
459 GC_stack_free_lists[index] = GC_stack_free_lists[index]->next;
460 } else {
461 #ifdef MMAP_STACKS
462 base = (ptr_t)mmap(0, search_sz + GC_page_size,
463 PROT_READ|PROT_WRITE, MAP_PRIVATE |MAP_NORESERVE,
464 GC_zfd, 0);
465 if (base == (ptr_t)-1)
466 {
467 *stack_size = 0;
468 return NULL;
469 }
470
471 mprotect(base, GC_page_size, PROT_NONE);
472 /* Should this use divHBLKSZ(search_sz + GC_page_size) ? -- cf */
473 GC_is_fresh((struct hblk *)base, divHBLKSZ(search_sz));
474 base += GC_page_size;
475
476 #else
477 base = (ptr_t) GC_scratch_alloc(search_sz + 2*GC_page_size);
478 if (base == NULL)
479 {
480 *stack_size = 0;
481 return NULL;
482 }
483
484 base = (ptr_t)(((word)base + GC_page_size) & ~(GC_page_size - 1));
485 /* Protect hottest page to detect overflow. */
486 # ifdef SOLARIS23_MPROTECT_BUG_FIXED
487 mprotect(base, GC_page_size, PROT_NONE);
488 # endif
489 GC_is_fresh((struct hblk *)base, divHBLKSZ(search_sz));
490
491 base += GC_page_size;
492 #endif
493 }
494 *stack_size = search_sz;
495 return(base);
496 }
497
498 /* Caller holds allocationlock. */
499 void GC_stack_free(ptr_t stack, size_t size)
500 {
501 register int index = 0;
502 register size_t search_sz = GC_min_stack_sz;
503 register struct stack_head *head;
504
505 #ifdef MMAP_STACKS
506 /* Zero pointers */
507 mmap(stack, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_NORESERVE|MAP_FIXED,
508 GC_zfd, 0);
509 #endif
510 while (search_sz < size) {
511 search_sz *= 2;
512 index++;
513 }
514 if (search_sz != size) ABORT("Bad stack size");
515
516 head = (struct stack_head *)(stack + search_sz - sizeof(struct stack_head));
517 head->next = GC_stack_free_lists[index];
518 head->base = stack;
519 GC_stack_free_lists[index] = head;
520 }
521
522 void GC_my_stack_limits();
523
524 /* Notify virtual dirty bit implementation that known empty parts of */
525 /* stacks do not contain useful data. */
526 /* Caller holds allocation lock. */
527 void GC_old_stacks_are_fresh()
528 {
529 /* No point in doing this for MMAP stacks - and pointers are zero'd out */
530 /* by the mmap in GC_stack_free */
531 #ifndef MMAP_STACKS
532 register int i;
533 register struct stack_head *s;
534 register ptr_t p;
535 register size_t sz;
536 register struct hblk * h;
537 int dummy;
538
539 for (i = 0, sz= GC_min_stack_sz; i < N_FREE_LISTS;
540 i++, sz *= 2) {
541 for (s = GC_stack_free_lists[i]; s != 0; s = s->next) {
542 p = s->base;
543 h = (struct hblk *)(((word)p + HBLKSIZE-1) & ~(HBLKSIZE-1));
544 if ((ptr_t)h == p) {
545 GC_is_fresh((struct hblk *)p, divHBLKSZ(sz));
546 } else {
547 GC_is_fresh((struct hblk *)p, divHBLKSZ(sz) - 1);
548 BZERO(p, (ptr_t)h - p);
549 }
550 }
551 }
552 #endif /* MMAP_STACKS */
553 GC_my_stack_limits();
554 }
555
556 /* The set of all known threads. We intercept thread creation and */
557 /* joins. We never actually create detached threads. We allocate all */
558 /* new thread stacks ourselves. These allow us to maintain this */
559 /* data structure. */
560
561 # define THREAD_TABLE_SZ 128 /* Must be power of 2 */
562 volatile GC_thread GC_threads[THREAD_TABLE_SZ];
563
564 void GC_push_thread_structures GC_PROTO((void))
565 {
566 GC_push_all((ptr_t)(GC_threads), (ptr_t)(GC_threads)+sizeof(GC_threads));
567 }
568
569 /* Add a thread to GC_threads. We assume it wasn't already there. */
570 /* Caller holds allocation lock. */
571 GC_thread GC_new_thread(thread_t id)
572 {
573 int hv = ((word)id) % THREAD_TABLE_SZ;
574 GC_thread result;
575 static struct GC_Thread_Rep first_thread;
576 static GC_bool first_thread_used = FALSE;
577
578 if (!first_thread_used) {
579 result = &first_thread;
580 first_thread_used = TRUE;
581 /* Dont acquire allocation lock, since we may already hold it. */
582 } else {
583 result = (struct GC_Thread_Rep *)
584 GC_INTERNAL_MALLOC(sizeof(struct GC_Thread_Rep), NORMAL);
585 }
586 if (result == 0) return(0);
587 result -> id = id;
588 result -> next = GC_threads[hv];
589 GC_threads[hv] = result;
590 /* result -> finished = 0; */
591 (void) cond_init(&(result->join_cv), USYNC_THREAD, 0);
592 return(result);
593 }
594
595 /* Delete a thread from GC_threads. We assume it is there. */
596 /* (The code intentionally traps if it wasn't.) */
597 /* Caller holds allocation lock. */
598 void GC_delete_thread(thread_t id)
599 {
600 int hv = ((word)id) % THREAD_TABLE_SZ;
601 register GC_thread p = GC_threads[hv];
602 register GC_thread prev = 0;
603
604 while (p -> id != id) {
605 prev = p;
606 p = p -> next;
607 }
608 if (prev == 0) {
609 GC_threads[hv] = p -> next;
610 } else {
611 prev -> next = p -> next;
612 }
613 }
614
615 /* Return the GC_thread correpsonding to a given thread_t. */
616 /* Returns 0 if it's not there. */
617 /* Caller holds allocation lock. */
618 GC_thread GC_lookup_thread(thread_t id)
619 {
620 int hv = ((word)id) % THREAD_TABLE_SZ;
621 register GC_thread p = GC_threads[hv];
622
623 while (p != 0 && p -> id != id) p = p -> next;
624 return(p);
625 }
626
627 /* Solaris 2/Intel uses an initial stack size limit slightly bigger than the
628 SPARC default of 8 MB. Account for this to warn only if the user has
629 raised the limit beyond the default.
630
631 This is identical to DFLSSIZ defined in <sys/vm_machparam.h>. This file
632 is installed in /usr/platform/`uname -m`/include, which is not in the
633 default include directory list, so copy the definition here. */
634 #ifdef I386
635 # define MAX_ORIG_STACK_SIZE (8 * 1024 * 1024 + ((USRSTACK) & 0x3FFFFF))
636 #else
637 # define MAX_ORIG_STACK_SIZE (8 * 1024 * 1024)
638 #endif
639
640 word GC_get_orig_stack_size() {
641 struct rlimit rl;
642 static int warned = 0;
643 int result;
644
645 if (getrlimit(RLIMIT_STACK, &rl) != 0) ABORT("getrlimit failed");
646 result = (word)rl.rlim_cur & ~(HBLKSIZE-1);
647 if (result > MAX_ORIG_STACK_SIZE) {
648 if (!warned) {
649 WARN("Large stack limit(%ld): only scanning 8 MB\n", result);
650 warned = 1;
651 }
652 result = MAX_ORIG_STACK_SIZE;
653 }
654 return result;
655 }
656
657 /* Notify dirty bit implementation of unused parts of my stack. */
658 /* Caller holds allocation lock. */
659 void GC_my_stack_limits()
660 {
661 int dummy;
662 register ptr_t hottest = (ptr_t)((word)(&dummy) & ~(HBLKSIZE-1));
663 register GC_thread me = GC_lookup_thread(thr_self());
664 register size_t stack_size = me -> stack_size;
665 register ptr_t stack;
666
667 if (stack_size == 0) {
668 /* original thread */
669 /* Empirically, what should be the stack page with lowest */
670 /* address is actually inaccessible. */
671 stack_size = GC_get_orig_stack_size() - GC_page_size;
672 stack = GC_stackbottom - stack_size + GC_page_size;
673 } else {
674 stack = me -> stack;
675 }
676 if (stack > hottest || stack + stack_size < hottest) {
677 ABORT("sp out of bounds");
678 }
679 GC_is_fresh((struct hblk *)stack, divHBLKSZ(hottest - stack));
680 }
681
682
683 /* We hold allocation lock. Should do exactly the right thing if the */
684 /* world is stopped. Should not fail if it isn't. */
685 void GC_push_all_stacks()
686 {
687 register int i;
688 register GC_thread p;
689 register ptr_t sp = GC_approx_sp();
690 register ptr_t bottom, top;
691 struct rlimit rl;
692
693 # define PUSH(bottom,top) \
694 if (GC_dirty_maintained) { \
695 GC_push_selected((bottom), (top), GC_page_was_ever_dirty, \
696 GC_push_all_stack); \
697 } else { \
698 GC_push_all_stack((bottom), (top)); \
699 }
700 GC_push_all_stack((ptr_t)GC_lwp_registers,
701 (ptr_t)GC_lwp_registers
702 + max_lwps * sizeof(GC_lwp_registers[0]));
703 for (i = 0; i < THREAD_TABLE_SZ; i++) {
704 for (p = GC_threads[i]; p != 0; p = p -> next) {
705 if (p -> stack_size != 0) {
706 bottom = p -> stack;
707 top = p -> stack + p -> stack_size;
708 } else {
709 /* The original stack. */
710 bottom = GC_stackbottom - GC_get_orig_stack_size() + GC_page_size;
711 top = GC_stackbottom;
712 }
713 if ((word)sp > (word)bottom && (word)sp < (word)top) bottom = sp;
714 PUSH(bottom, top);
715 }
716 }
717 }
718
719
720 int GC_is_thread_stack(ptr_t addr)
721 {
722 register int i;
723 register GC_thread p;
724 register ptr_t bottom, top;
725
726 for (i = 0; i < THREAD_TABLE_SZ; i++) {
727 for (p = GC_threads[i]; p != 0; p = p -> next) {
728 if (p -> stack_size != 0) {
729 if (p -> stack <= addr &&
730 addr < p -> stack + p -> stack_size)
731 return 1;
732 }
733 }
734 }
735 return 0;
736 }
737
738 /* The only thread that ever really performs a thr_join. */
739 void * GC_thr_daemon(void * dummy)
740 {
741 void *status;
742 thread_t departed;
743 register GC_thread t;
744 register int i;
745 register int result;
746
747 for(;;) {
748 start:
749 result = thr_join((thread_t)0, &departed, &status);
750 LOCK();
751 if (result != 0) {
752 /* No more threads; wait for create. */
753 for (i = 0; i < THREAD_TABLE_SZ; i++) {
754 for (t = GC_threads[i]; t != 0; t = t -> next) {
755 if (!(t -> flags & (DETACHED | FINISHED))) {
756 UNLOCK();
757 goto start; /* Thread started just before we */
758 /* acquired the lock. */
759 }
760 }
761 }
762 cond_wait(&GC_create_cv, &GC_allocate_ml);
763 UNLOCK();
764 } else {
765 t = GC_lookup_thread(departed);
766 GC_multithreaded--;
767 if (!(t -> flags & CLIENT_OWNS_STACK)) {
768 GC_stack_free(t -> stack, t -> stack_size);
769 }
770 if (t -> flags & DETACHED) {
771 GC_delete_thread(departed);
772 } else {
773 t -> status = status;
774 t -> flags |= FINISHED;
775 cond_signal(&(t -> join_cv));
776 cond_broadcast(&GC_prom_join_cv);
777 }
778 UNLOCK();
779 }
780 }
781 }
782
783 /* We hold the allocation lock, or caller ensures that 2 instances */
784 /* cannot be invoked concurrently. */
785 void GC_thr_init(void)
786 {
787 GC_thread t;
788 thread_t tid;
789 int ret;
790
791 if (GC_thr_initialized)
792 return;
793 GC_thr_initialized = TRUE;
794 GC_min_stack_sz = ((thr_min_stack() + 32*1024 + HBLKSIZE-1)
795 & ~(HBLKSIZE - 1));
796 #ifdef MMAP_STACKS
797 GC_zfd = open("/dev/zero", O_RDONLY);
798 if (GC_zfd == -1)
799 ABORT("Can't open /dev/zero");
800 #endif /* MMAP_STACKS */
801 cond_init(&GC_prom_join_cv, USYNC_THREAD, 0);
802 cond_init(&GC_create_cv, USYNC_THREAD, 0);
803 /* Add the initial thread, so we can stop it. */
804 t = GC_new_thread(thr_self());
805 t -> stack_size = 0;
806 t -> flags = DETACHED | CLIENT_OWNS_STACK;
807 ret = thr_create(0 /* stack */, 0 /* stack_size */, GC_thr_daemon,
808 0 /* arg */, THR_DETACHED | THR_DAEMON,
809 &tid /* thread_id */);
810 if (ret != 0) {
811 GC_err_printf1("Thr_create returned %ld\n", ret);
812 ABORT("Cant fork daemon");
813 }
814 thr_setprio(tid, 126);
815 }
816
817 /* We acquire the allocation lock to prevent races with */
818 /* stopping/starting world. */
819 /* This is no more correct than the underlying Solaris 2.X */
820 /* implementation. Under 2.3 THIS IS BROKEN. */
821 int GC_thr_suspend(thread_t target_thread)
822 {
823 GC_thread t;
824 int result;
825
826 LOCK();
827 result = thr_suspend(target_thread);
828 if (result == 0) {
829 t = GC_lookup_thread(target_thread);
830 if (t == 0) ABORT("thread unknown to GC");
831 t -> flags |= SUSPNDED;
832 }
833 UNLOCK();
834 return(result);
835 }
836
837 int GC_thr_continue(thread_t target_thread)
838 {
839 GC_thread t;
840 int result;
841
842 LOCK();
843 result = thr_continue(target_thread);
844 if (result == 0) {
845 t = GC_lookup_thread(target_thread);
846 if (t == 0) ABORT("thread unknown to GC");
847 t -> flags &= ~SUSPNDED;
848 }
849 UNLOCK();
850 return(result);
851 }
852
853 int GC_thr_join(thread_t wait_for, thread_t *departed, void **status)
854 {
855 register GC_thread t;
856 int result = 0;
857
858 LOCK();
859 if (wait_for == 0) {
860 register int i;
861 register GC_bool thread_exists;
862
863 for (;;) {
864 thread_exists = FALSE;
865 for (i = 0; i < THREAD_TABLE_SZ; i++) {
866 for (t = GC_threads[i]; t != 0; t = t -> next) {
867 if (!(t -> flags & DETACHED)) {
868 if (t -> flags & FINISHED) {
869 goto found;
870 }
871 thread_exists = TRUE;
872 }
873 }
874 }
875 if (!thread_exists) {
876 result = ESRCH;
877 goto out;
878 }
879 cond_wait(&GC_prom_join_cv, &GC_allocate_ml);
880 }
881 } else {
882 t = GC_lookup_thread(wait_for);
883 if (t == 0 || t -> flags & DETACHED) {
884 result = ESRCH;
885 goto out;
886 }
887 if (wait_for == thr_self()) {
888 result = EDEADLK;
889 goto out;
890 }
891 while (!(t -> flags & FINISHED)) {
892 cond_wait(&(t -> join_cv), &GC_allocate_ml);
893 }
894
895 }
896 found:
897 if (status) *status = t -> status;
898 if (departed) *departed = t -> id;
899 cond_destroy(&(t -> join_cv));
900 GC_delete_thread(t -> id);
901 out:
902 UNLOCK();
903 return(result);
904 }
905
906
907 int
908 GC_thr_create(void *stack_base, size_t stack_size,
909 void *(*start_routine)(void *), void *arg, long flags,
910 thread_t *new_thread)
911 {
912 int result;
913 GC_thread t;
914 thread_t my_new_thread;
915 word my_flags = 0;
916 void * stack = stack_base;
917
918 LOCK();
919 if (!GC_is_initialized) GC_init_inner();
920 GC_multithreaded++;
921 if (stack == 0) {
922 if (stack_size == 0) stack_size = 1024*1024;
923 stack = (void *)GC_stack_alloc(&stack_size);
924 if (stack == 0) {
925 GC_multithreaded--;
926 UNLOCK();
927 return(ENOMEM);
928 }
929 } else {
930 my_flags |= CLIENT_OWNS_STACK;
931 }
932 if (flags & THR_DETACHED) my_flags |= DETACHED;
933 if (flags & THR_SUSPENDED) my_flags |= SUSPNDED;
934 result = thr_create(stack, stack_size, start_routine,
935 arg, flags & ~THR_DETACHED, &my_new_thread);
936 if (result == 0) {
937 t = GC_new_thread(my_new_thread);
938 t -> flags = my_flags;
939 if (!(my_flags & DETACHED)) cond_init(&(t -> join_cv), USYNC_THREAD, 0);
940 t -> stack = stack;
941 t -> stack_size = stack_size;
942 if (new_thread != 0) *new_thread = my_new_thread;
943 cond_signal(&GC_create_cv);
944 } else {
945 GC_multithreaded--;
946 if (!(my_flags & CLIENT_OWNS_STACK)) {
947 GC_stack_free(stack, stack_size);
948 }
949 }
950 UNLOCK();
951 return(result);
952 }
953
954 # else /* !GC_SOLARIS_THREADS */
955
956 #ifndef LINT
957 int GC_no_sunOS_threads;
958 #endif
959 #endif