2 * This software is part of the SBCL system. See the README file for
5 * This software is derived from the CMU CL system, which was
6 * written at Carnegie Mellon University and released into the
7 * public domain. The software is in the public domain and is
8 * provided with absolutely no warranty. See the COPYING and CREDITS
9 * files for more information.
17 #ifndef LISP_FEATURE_WIN32
23 #include <sys/types.h>
24 #ifndef LISP_FEATURE_WIN32
28 #ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER
29 #include <mach/mach.h>
30 #include <mach/mach_error.h>
31 #include <mach/mach_types.h>
35 #include "validate.h" /* for BINDING_STACK_SIZE etc */
38 #include "target-arch-os.h"
42 #include "genesis/cons.h"
43 #include "genesis/fdefn.h"
44 #include "interr.h" /* for lose() */
46 #include "gc-internal.h"
48 #ifdef LISP_FEATURE_WIN32
50 * Win32 doesn't have SIGSTKSZ, and we're not switching stacks anyway,
51 * so define it arbitrarily
56 #if defined(LISP_FEATURE_DARWIN) && defined(LISP_FEATURE_SB_THREAD)
57 #define DELAY_THREAD_POST_MORTEM 5
58 #define LOCK_CREATE_THREAD
61 #ifdef LISP_FEATURE_FREEBSD
62 #define CREATE_CLEANUP_THREAD
63 #define LOCK_CREATE_THREAD
66 #ifdef LISP_FEATURE_SB_THREAD
67 struct thread_post_mortem {
68 #ifdef DELAY_THREAD_POST_MORTEM
69 struct thread_post_mortem *next;
71 os_thread_t os_thread;
72 pthread_attr_t *os_attr;
73 os_vm_address_t os_address;
76 #ifdef DELAY_THREAD_POST_MORTEM
77 static int pending_thread_post_mortem_count = 0;
78 pthread_mutex_t thread_post_mortem_lock = PTHREAD_MUTEX_INITIALIZER;
80 static struct thread_post_mortem * volatile pending_thread_post_mortem = 0;
83 int dynamic_values_bytes=TLS_SIZE*sizeof(lispobj); /* same for all threads */
84 struct thread *all_threads;
85 extern struct interrupt_data * global_interrupt_data;
87 #ifdef LISP_FEATURE_SB_THREAD
88 pthread_mutex_t all_threads_lock = PTHREAD_MUTEX_INITIALIZER;
89 #ifdef LOCK_CREATE_THREAD
90 static pthread_mutex_t create_thread_lock = PTHREAD_MUTEX_INITIALIZER;
92 #ifdef LISP_FEATURE_GCC_TLS
93 __thread struct thread *current_thread;
95 pthread_key_t lisp_thread = 0;
98 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
99 extern lispobj call_into_lisp_first_time(lispobj fun, lispobj *args, int nargs);
103 link_thread(struct thread *th)
105 if (all_threads) all_threads->prev=th;
106 th->next=all_threads;
111 #ifdef LISP_FEATURE_SB_THREAD
113 unlink_thread(struct thread *th)
116 th->prev->next = th->next;
118 all_threads = th->next;
120 th->next->prev = th->prev;
123 /* Only access thread state with blockables blocked. */
125 thread_state(struct thread *thread)
129 block_blockable_signals(NULL, &old);
130 os_sem_wait(thread->state_sem, "thread_state");
131 state = thread->state;
132 os_sem_post(thread->state_sem, "thread_state");
133 thread_sigmask(SIG_SETMASK, &old, NULL);
138 set_thread_state(struct thread *thread, lispobj state)
140 int i, waitcount = 0;
142 block_blockable_signals(NULL, &old);
143 os_sem_wait(thread->state_sem, "set_thread_state");
144 if (thread->state != state) {
145 if ((STATE_STOPPED==state) ||
146 (STATE_DEAD==state)) {
147 waitcount = thread->state_not_running_waitcount;
148 thread->state_not_running_waitcount = 0;
149 for (i=0; i<waitcount; i++)
150 os_sem_post(thread->state_not_running_sem, "set_thread_state (not running)");
152 if ((STATE_RUNNING==state) ||
153 (STATE_DEAD==state)) {
154 waitcount = thread->state_not_stopped_waitcount;
155 thread->state_not_stopped_waitcount = 0;
156 for (i=0; i<waitcount; i++)
157 os_sem_post(thread->state_not_stopped_sem, "set_thread_state (not stopped)");
159 thread->state = state;
161 os_sem_post(thread->state_sem, "set_thread_state");
162 thread_sigmask(SIG_SETMASK, &old, NULL);
166 wait_for_thread_state_change(struct thread *thread, lispobj state)
170 block_blockable_signals(NULL, &old);
172 os_sem_wait(thread->state_sem, "wait_for_thread_state_change");
173 if (thread->state == state) {
176 wait_sem = thread->state_not_running_sem;
177 thread->state_not_running_waitcount++;
180 wait_sem = thread->state_not_stopped_sem;
181 thread->state_not_stopped_waitcount++;
184 lose("Invalid state in wait_for_thread_state_change: "OBJ_FMTX"\n", state);
189 os_sem_post(thread->state_sem, "wait_for_thread_state_change");
191 os_sem_wait(wait_sem, "wait_for_thread_state_change");
194 thread_sigmask(SIG_SETMASK, &old, NULL);
199 initial_thread_trampoline(struct thread *th)
202 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
203 lispobj *args = NULL;
205 #ifdef LISP_FEATURE_SB_THREAD
206 pthread_setspecific(lisp_thread, (void *)1);
208 #if defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_PPC)
209 /* SIG_STOP_FOR_GC defaults to blocked on PPC? */
210 unblock_gc_signals(0,0);
212 function = th->no_tls_value_marker;
213 th->no_tls_value_marker = NO_TLS_VALUE_MARKER_WIDETAG;
214 if(arch_os_thread_init(th)==0) return 1;
216 th->os_thread=thread_self();
217 #ifndef LISP_FEATURE_WIN32
218 protect_control_stack_hard_guard_page(1, NULL);
219 protect_binding_stack_hard_guard_page(1, NULL);
220 protect_alien_stack_hard_guard_page(1, NULL);
221 protect_control_stack_guard_page(1, NULL);
222 protect_binding_stack_guard_page(1, NULL);
223 protect_alien_stack_guard_page(1, NULL);
226 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
227 return call_into_lisp_first_time(function,args,0);
229 return funcall0(function);
233 #ifdef LISP_FEATURE_SB_THREAD
234 #define THREAD_STATE_LOCK_SIZE \
235 ((sizeof(os_sem_t))+(sizeof(os_sem_t))+(sizeof(os_sem_t)))
237 #define THREAD_STATE_LOCK_SIZE 0
240 #define THREAD_STRUCT_SIZE (thread_control_stack_size + BINDING_STACK_SIZE + \
242 THREAD_STATE_LOCK_SIZE + \
243 dynamic_values_bytes + \
245 THREAD_ALIGNMENT_BYTES)
247 #ifdef LISP_FEATURE_SB_THREAD
248 /* THREAD POST MORTEM CLEANUP
250 * Memory allocated for the thread stacks cannot be reclaimed while
251 * the thread is still alive, so we need a mechanism for post mortem
252 * cleanups. FIXME: We actually have three, for historical reasons as
253 * the saying goes. Do we really need three? Nikodemus guesses that
254 * not anymore, now that we properly call pthread_attr_destroy before
255 * freeing the stack. */
257 static struct thread_post_mortem *
258 plan_thread_post_mortem(struct thread *corpse)
261 struct thread_post_mortem *post_mortem = malloc(sizeof(struct thread_post_mortem));
262 gc_assert(post_mortem);
263 post_mortem->os_thread = corpse->os_thread;
264 post_mortem->os_attr = corpse->os_attr;
265 post_mortem->os_address = corpse->os_address;
266 #ifdef DELAY_THREAD_POST_MORTEM
267 post_mortem->next = NULL;
271 /* FIXME: When does this happen? */
277 perform_thread_post_mortem(struct thread_post_mortem *post_mortem)
279 #ifdef CREATE_POST_MORTEM_THREAD
280 pthread_detach(pthread_self());
283 gc_assert(!pthread_join(post_mortem->os_thread, NULL));
284 gc_assert(!pthread_attr_destroy(post_mortem->os_attr));
285 free(post_mortem->os_attr);
286 os_invalidate(post_mortem->os_address, THREAD_STRUCT_SIZE);
292 schedule_thread_post_mortem(struct thread *corpse)
294 struct thread_post_mortem *post_mortem = NULL;
296 post_mortem = plan_thread_post_mortem(corpse);
298 #ifdef DELAY_THREAD_POST_MORTEM
299 pthread_mutex_lock(&thread_post_mortem_lock);
300 /* First stick the new post mortem to the end of the queue. */
301 if (pending_thread_post_mortem) {
302 struct thread_post_mortem *next = pending_thread_post_mortem;
306 next->next = post_mortem;
308 pending_thread_post_mortem = post_mortem;
310 /* Then, if there are enough things in the queue, clean up one
311 * from the head -- or increment the count, and null out the
312 * post_mortem we have. */
313 if (pending_thread_post_mortem_count > DELAY_THREAD_POST_MORTEM) {
314 post_mortem = pending_thread_post_mortem;
315 pending_thread_post_mortem = post_mortem->next;
317 pending_thread_post_mortem_count++;
320 pthread_mutex_unlock(&thread_post_mortem_lock);
321 /* Finally run, the cleanup, if any. */
322 perform_thread_post_mortem(post_mortem);
323 #elif defined(CREATE_POST_MORTEM_THREAD)
324 gc_assert(!pthread_create(&thread, NULL, perform_thread_post_mortem, post_mortem));
326 post_mortem = (struct thread_post_mortem *)
327 swap_lispobjs((lispobj *)(void *)&pending_thread_post_mortem,
328 (lispobj)post_mortem);
329 perform_thread_post_mortem(post_mortem);
334 /* this is the first thing that runs in the child (which is why the
335 * silly calling convention). Basically it calls the user's requested
336 * lisp function after doing arch_os_thread_init and whatever other
337 * bookkeeping needs to be done
340 new_thread_trampoline(struct thread *th)
343 int result, lock_ret;
345 FSHOW((stderr,"/creating thread %lu\n", thread_self()));
346 check_deferrables_blocked_or_lose(0);
347 check_gc_signals_unblocked_or_lose(0);
348 pthread_setspecific(lisp_thread, (void *)1);
349 function = th->no_tls_value_marker;
350 th->no_tls_value_marker = NO_TLS_VALUE_MARKER_WIDETAG;
351 if(arch_os_thread_init(th)==0) {
352 /* FIXME: handle error */
353 lose("arch_os_thread_init failed\n");
356 th->os_thread=thread_self();
357 protect_control_stack_guard_page(1, NULL);
358 protect_binding_stack_guard_page(1, NULL);
359 protect_alien_stack_guard_page(1, NULL);
360 /* Since GC can only know about this thread from the all_threads
361 * list and we're just adding this thread to it, there is no
362 * danger of deadlocking even with SIG_STOP_FOR_GC blocked (which
364 lock_ret = pthread_mutex_lock(&all_threads_lock);
365 gc_assert(lock_ret == 0);
367 lock_ret = pthread_mutex_unlock(&all_threads_lock);
368 gc_assert(lock_ret == 0);
370 result = funcall0(function);
373 block_blockable_signals(0, 0);
374 set_thread_state(th, STATE_DEAD);
376 /* SIG_STOP_FOR_GC is blocked and GC might be waiting for this
377 * thread, but since we are already dead it won't wait long. */
378 lock_ret = pthread_mutex_lock(&all_threads_lock);
379 gc_assert(lock_ret == 0);
381 gc_alloc_update_page_tables(BOXED_PAGE_FLAG, &th->alloc_region);
383 pthread_mutex_unlock(&all_threads_lock);
384 gc_assert(lock_ret == 0);
386 if(th->tls_cookie>=0) arch_os_thread_cleanup(th);
387 os_sem_destroy(th->state_sem);
388 os_sem_destroy(th->state_not_running_sem);
389 os_sem_destroy(th->state_not_stopped_sem);
391 os_invalidate((os_vm_address_t)th->interrupt_data,
392 (sizeof (struct interrupt_data)));
394 #ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER
395 FSHOW((stderr, "Deallocating mach port %x\n", THREAD_STRUCT_TO_EXCEPTION_PORT(th)));
396 mach_port_move_member(current_mach_task,
397 THREAD_STRUCT_TO_EXCEPTION_PORT(th),
399 mach_port_deallocate(current_mach_task,
400 THREAD_STRUCT_TO_EXCEPTION_PORT(th));
401 mach_port_destroy(current_mach_task,
402 THREAD_STRUCT_TO_EXCEPTION_PORT(th));
405 schedule_thread_post_mortem(th);
406 FSHOW((stderr,"/exiting thread %lu\n", thread_self()));
410 #endif /* LISP_FEATURE_SB_THREAD */
413 free_thread_struct(struct thread *th)
415 if (th->interrupt_data)
416 os_invalidate((os_vm_address_t) th->interrupt_data,
417 (sizeof (struct interrupt_data)));
418 os_invalidate((os_vm_address_t) th->os_address,
422 #ifdef LISP_FEATURE_SB_THREAD
423 /* FIXME: should be MAX_INTERRUPTS -1 ? */
424 const unsigned int tls_index_start =
425 MAX_INTERRUPTS + sizeof(struct thread)/sizeof(lispobj);
428 /* this is called from any other thread to create the new one, and
429 * initialize all parts of it that can be initialized from another
433 static struct thread *
434 create_thread_struct(lispobj initial_function) {
435 union per_thread_data *per_thread;
436 struct thread *th=0; /* subdue gcc */
438 void *aligned_spaces=0;
439 #ifdef LISP_FEATURE_SB_THREAD
443 /* May as well allocate all the spaces at once: it saves us from
444 * having to decide what to do if only some of the allocations
445 * succeed. SPACES must be appropriately aligned, since the GC
446 * expects the control stack to start at a page boundary -- and
447 * the OS may have even more rigorous requirements. We can't rely
448 * on the alignment passed from os_validate, since that might
449 * assume the current (e.g. 4k) pagesize, while we calculate with
450 * the biggest (e.g. 64k) pagesize allowed by the ABI. */
451 spaces=os_validate(0, THREAD_STRUCT_SIZE);
454 /* Aligning up is safe as THREAD_STRUCT_SIZE has
455 * THREAD_ALIGNMENT_BYTES padding. */
456 aligned_spaces = (void *)((((unsigned long)(char *)spaces)
457 + THREAD_ALIGNMENT_BYTES-1)
458 &~(unsigned long)(THREAD_ALIGNMENT_BYTES-1));
459 per_thread=(union per_thread_data *)
461 thread_control_stack_size+
464 THREAD_STATE_LOCK_SIZE);
466 #ifdef LISP_FEATURE_SB_THREAD
467 for(i = 0; i < (dynamic_values_bytes / sizeof(lispobj)); i++)
468 per_thread->dynamic_values[i] = NO_TLS_VALUE_MARKER_WIDETAG;
469 if (all_threads == 0) {
470 if(SymbolValue(FREE_TLS_INDEX,0)==UNBOUND_MARKER_WIDETAG) {
471 SetSymbolValue(FREE_TLS_INDEX,tls_index_start << WORD_SHIFT,0);
472 SetSymbolValue(TLS_INDEX_LOCK,make_fixnum(0),0);
474 #define STATIC_TLS_INIT(sym,field) \
475 ((struct symbol *)(sym-OTHER_POINTER_LOWTAG))->tls_index= \
476 (THREAD_SLOT_OFFSET_WORDS(field) << WORD_SHIFT)
478 STATIC_TLS_INIT(BINDING_STACK_START,binding_stack_start);
479 #ifdef BINDING_STACK_POINTER
480 STATIC_TLS_INIT(BINDING_STACK_POINTER,binding_stack_pointer);
482 STATIC_TLS_INIT(CONTROL_STACK_START,control_stack_start);
483 STATIC_TLS_INIT(CONTROL_STACK_END,control_stack_end);
485 STATIC_TLS_INIT(ALIEN_STACK,alien_stack_pointer);
487 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
488 STATIC_TLS_INIT(PSEUDO_ATOMIC_BITS,pseudo_atomic_bits);
490 #undef STATIC_TLS_INIT
494 th=&per_thread->thread;
495 th->os_address = spaces;
496 th->control_stack_start = aligned_spaces;
497 th->binding_stack_start=
498 (lispobj*)((void*)th->control_stack_start+thread_control_stack_size);
499 th->control_stack_end = th->binding_stack_start;
500 th->control_stack_guard_page_protected = T;
501 th->alien_stack_start=
502 (lispobj*)((void*)th->binding_stack_start+BINDING_STACK_SIZE);
503 set_binding_stack_pointer(th,th->binding_stack_start);
506 #ifdef LISP_FEATURE_SB_THREAD
507 th->os_attr=malloc(sizeof(pthread_attr_t));
508 th->state_sem=(os_sem_t *)((void *)th->alien_stack_start + ALIEN_STACK_SIZE);
509 th->state_not_running_sem=(os_sem_t *)
510 ((void *)th->state_sem + (sizeof(os_sem_t)));
511 th->state_not_stopped_sem=(os_sem_t *)
512 ((void *)th->state_not_running_sem + (sizeof(os_sem_t)));
513 th->state_not_running_waitcount = 0;
514 th->state_not_stopped_waitcount = 0;
515 os_sem_init(th->state_sem, 1);
516 os_sem_init(th->state_not_running_sem, 0);
517 os_sem_init(th->state_not_stopped_sem, 0);
519 th->state=STATE_RUNNING;
520 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
521 th->alien_stack_pointer=((void *)th->alien_stack_start
522 + ALIEN_STACK_SIZE-N_WORD_BYTES);
524 th->alien_stack_pointer=((void *)th->alien_stack_start);
526 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64) || defined(LISP_FEATURE_SB_THREAD)
527 th->pseudo_atomic_bits=0;
529 #ifdef LISP_FEATURE_GENCGC
530 gc_set_region_empty(&th->alloc_region);
532 #ifdef LISP_FEATURE_SB_THREAD
533 /* This parallels the same logic in globals.c for the
534 * single-threaded foreign_function_call_active, KLUDGE and
536 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
537 th->foreign_function_call_active = 0;
539 th->foreign_function_call_active = 1;
543 #ifndef LISP_FEATURE_SB_THREAD
544 /* the tls-points-into-struct-thread trick is only good for threaded
545 * sbcl, because unithread sbcl doesn't have tls. So, we copy the
546 * appropriate values from struct thread here, and make sure that
547 * we use the appropriate SymbolValue macros to access any of the
548 * variable quantities from the C runtime. It's not quite OAOOM,
549 * it just feels like it */
550 SetSymbolValue(BINDING_STACK_START,(lispobj)th->binding_stack_start,th);
551 SetSymbolValue(CONTROL_STACK_START,(lispobj)th->control_stack_start,th);
552 SetSymbolValue(CONTROL_STACK_END,(lispobj)th->control_stack_end,th);
553 #if defined(LISP_FEATURE_X86) || defined (LISP_FEATURE_X86_64)
554 SetSymbolValue(ALIEN_STACK,(lispobj)th->alien_stack_pointer,th);
555 SetSymbolValue(PSEUDO_ATOMIC_BITS,(lispobj)th->pseudo_atomic_bits,th);
558 bind_variable(CURRENT_CATCH_BLOCK,make_fixnum(0),th);
559 bind_variable(CURRENT_UNWIND_PROTECT_BLOCK,make_fixnum(0),th);
560 bind_variable(FREE_INTERRUPT_CONTEXT_INDEX,make_fixnum(0),th);
561 bind_variable(INTERRUPT_PENDING, NIL,th);
562 bind_variable(INTERRUPTS_ENABLED,T,th);
563 bind_variable(ALLOW_WITH_INTERRUPTS,T,th);
564 bind_variable(GC_PENDING,NIL,th);
565 bind_variable(ALLOC_SIGNAL,NIL,th);
566 #ifdef PINNED_OBJECTS
567 bind_variable(PINNED_OBJECTS,NIL,th);
569 #ifdef LISP_FEATURE_SB_THREAD
570 bind_variable(STOP_FOR_GC_PENDING,NIL,th);
572 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
573 access_control_stack_pointer(th)=th->control_stack_start;
576 th->interrupt_data = (struct interrupt_data *)
577 os_validate(0,(sizeof (struct interrupt_data)));
578 if (!th->interrupt_data) {
579 free_thread_struct(th);
582 th->interrupt_data->pending_handler = 0;
583 th->interrupt_data->gc_blocked_deferrables = 0;
584 #ifdef LISP_FEATURE_PPC
585 th->interrupt_data->allocation_trap_context = 0;
587 th->no_tls_value_marker=initial_function;
593 #ifdef LISP_FEATURE_MACH_EXCEPTION_HANDLER
594 mach_port_t setup_mach_exception_handling_thread();
595 kern_return_t mach_thread_init(mach_port_t thread_exception_port);
599 void create_initial_thread(lispobj initial_function) {
600 struct thread *th=create_thread_struct(initial_function);
601 #ifdef LISP_FEATURE_SB_THREAD
602 pthread_key_create(&lisp_thread, 0);
605 initial_thread_trampoline(th); /* no return */
606 } else lose("can't create initial thread\n");
609 #ifdef LISP_FEATURE_SB_THREAD
611 #ifndef __USE_XOPEN2K
612 extern int pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
616 boolean create_os_thread(struct thread *th,os_thread_t *kid_tid)
618 /* The new thread inherits the restrictive signal mask set here,
619 * and enables signals again when it is set up properly. */
622 int retcode = 0, initcode;
624 FSHOW_SIGNAL((stderr,"/create_os_thread: creating new thread\n"));
626 /* Blocking deferrable signals is enough, no need to block
627 * SIG_STOP_FOR_GC because the child process is not linked onto
628 * all_threads until it's ready. */
629 block_deferrable_signals(0, &oldset);
631 #ifdef LOCK_CREATE_THREAD
632 retcode = pthread_mutex_lock(&create_thread_lock);
633 gc_assert(retcode == 0);
634 FSHOW_SIGNAL((stderr,"/create_os_thread: got lock\n"));
637 if((initcode = pthread_attr_init(th->os_attr)) ||
638 /* call_into_lisp_first_time switches the stack for the initial
639 * thread. For the others, we use this. */
640 (pthread_attr_setstack(th->os_attr,th->control_stack_start,
641 thread_control_stack_size)) ||
642 (retcode = pthread_create
643 (kid_tid,th->os_attr,(void *(*)(void *))new_thread_trampoline,th))) {
644 FSHOW_SIGNAL((stderr, "init = %d\n", initcode));
645 FSHOW_SIGNAL((stderr, "pthread_create returned %d, errno %d\n",
648 perror("create_os_thread");
653 #ifdef LOCK_CREATE_THREAD
654 retcode = pthread_mutex_unlock(&create_thread_lock);
655 gc_assert(retcode == 0);
656 FSHOW_SIGNAL((stderr,"/create_os_thread: released lock\n"));
658 thread_sigmask(SIG_SETMASK,&oldset,0);
662 os_thread_t create_thread(lispobj initial_function) {
663 struct thread *th, *thread = arch_os_get_current_thread();
664 os_thread_t kid_tid = 0;
666 /* Must defend against async unwinds. */
667 if (SymbolValue(INTERRUPTS_ENABLED, thread) != NIL)
668 lose("create_thread is not safe when interrupts are enabled.\n");
670 /* Assuming that a fresh thread struct has no lisp objects in it,
671 * linking it to all_threads can be left to the thread itself
672 * without fear of gc lossage. initial_function violates this
673 * assumption and must stay pinned until the child starts up. */
674 th = create_thread_struct(initial_function);
675 if (th && !create_os_thread(th,&kid_tid)) {
676 free_thread_struct(th);
682 /* stopping the world is a two-stage process. From this thread we signal
683 * all the others with SIG_STOP_FOR_GC. The handler for this signal does
684 * the usual pseudo-atomic checks (we don't want to stop a thread while
685 * it's in the middle of allocation) then waits for another SIG_STOP_FOR_GC.
688 /* To avoid deadlocks when gc stops the world all clients of each
689 * mutex must enable or disable SIG_STOP_FOR_GC for the duration of
690 * holding the lock, but they must agree on which. */
691 void gc_stop_the_world()
693 struct thread *p,*th=arch_os_get_current_thread();
694 int status, lock_ret;
695 #ifdef LOCK_CREATE_THREAD
696 /* KLUDGE: Stopping the thread during pthread_create() causes deadlock
698 FSHOW_SIGNAL((stderr,"/gc_stop_the_world:waiting on create_thread_lock\n"));
699 lock_ret = pthread_mutex_lock(&create_thread_lock);
700 gc_assert(lock_ret == 0);
701 FSHOW_SIGNAL((stderr,"/gc_stop_the_world:got create_thread_lock\n"));
703 FSHOW_SIGNAL((stderr,"/gc_stop_the_world:waiting on lock\n"));
704 /* keep threads from starting while the world is stopped. */
705 lock_ret = pthread_mutex_lock(&all_threads_lock); \
706 gc_assert(lock_ret == 0);
708 FSHOW_SIGNAL((stderr,"/gc_stop_the_world:got lock\n"));
709 /* stop all other threads by sending them SIG_STOP_FOR_GC */
710 for(p=all_threads; p; p=p->next) {
711 gc_assert(p->os_thread != 0);
712 FSHOW_SIGNAL((stderr,"/gc_stop_the_world: thread=%lu, state=%x\n",
713 p->os_thread, thread_state(p)));
714 if((p!=th) && ((thread_state(p)==STATE_RUNNING))) {
715 FSHOW_SIGNAL((stderr,"/gc_stop_the_world: suspending thread %lu\n",
717 /* We already hold all_thread_lock, P can become DEAD but
718 * cannot exit, ergo it's safe to use pthread_kill. */
719 status=pthread_kill(p->os_thread,SIG_STOP_FOR_GC);
721 /* This thread has exited. */
722 gc_assert(thread_state(p)==STATE_DEAD);
724 lose("cannot send suspend thread=%lu: %d, %s\n",
725 p->os_thread,status,strerror(status));
729 FSHOW_SIGNAL((stderr,"/gc_stop_the_world:signals sent\n"));
730 for(p=all_threads;p;p=p->next) {
734 "/gc_stop_the_world: waiting for thread=%lu: state=%x\n",
735 p->os_thread, thread_state(p)));
736 wait_for_thread_state_change(p, STATE_RUNNING);
737 if (p->state == STATE_RUNNING)
738 lose("/gc_stop_the_world: unexpected state");
741 FSHOW_SIGNAL((stderr,"/gc_stop_the_world:end\n"));
744 void gc_start_the_world()
746 struct thread *p,*th=arch_os_get_current_thread();
748 /* if a resumed thread creates a new thread before we're done with
749 * this loop, the new thread will get consed on the front of
750 * all_threads, but it won't have been stopped so won't need
752 FSHOW_SIGNAL((stderr,"/gc_start_the_world:begin\n"));
753 for(p=all_threads;p;p=p->next) {
754 gc_assert(p->os_thread!=0);
756 lispobj state = thread_state(p);
757 if (state != STATE_DEAD) {
758 if(state != STATE_STOPPED) {
759 lose("gc_start_the_world: wrong thread state is %d\n",
760 fixnum_value(state));
762 FSHOW_SIGNAL((stderr, "/gc_start_the_world: resuming %lu\n",
764 set_thread_state(p, STATE_RUNNING);
769 lock_ret = pthread_mutex_unlock(&all_threads_lock);
770 gc_assert(lock_ret == 0);
771 #ifdef LOCK_CREATE_THREAD
772 lock_ret = pthread_mutex_unlock(&create_thread_lock);
773 gc_assert(lock_ret == 0);
776 FSHOW_SIGNAL((stderr,"/gc_start_the_world:end\n"));
783 #ifdef LISP_FEATURE_SB_THREAD
784 return sched_yield();
790 /* If the thread id given does not belong to a running thread (it has
791 * exited or never even existed) pthread_kill _may_ fail with ESRCH,
792 * but it is also allowed to just segfault, see
793 * <http://udrepper.livejournal.com/16844.html>.
795 * Relying on thread ids can easily backfire since ids are recycled
796 * (NPTL recycles them extremely fast) so a signal can be sent to
797 * another process if the one it was sent to exited.
799 * We send signals in two places: signal_interrupt_thread sends a
800 * signal that's harmless if delivered to another thread, but
801 * SIG_STOP_FOR_GC is fatal.
803 * For these reasons, we must make sure that the thread is still alive
804 * when the pthread_kill is called and return if the thread is
807 kill_safely(os_thread_t os_thread, int signal)
809 FSHOW_SIGNAL((stderr,"/kill_safely: %lu, %d\n", os_thread, signal));
811 #ifdef LISP_FEATURE_SB_THREAD
813 struct thread *thread;
814 /* pthread_kill is not async signal safe and we don't want to be
815 * interrupted while holding the lock. */
816 block_deferrable_signals(0, &oldset);
817 pthread_mutex_lock(&all_threads_lock);
818 for (thread = all_threads; thread; thread = thread->next) {
819 if (thread->os_thread == os_thread) {
820 int status = pthread_kill(os_thread, signal);
822 lose("kill_safely: pthread_kill failed with %d\n", status);
826 pthread_mutex_unlock(&all_threads_lock);
827 thread_sigmask(SIG_SETMASK,&oldset,0);
835 lose("kill_safely: who do you want to kill? %d?\n", os_thread);
836 /* Dubious (as in don't know why it works) workaround for the
837 * signal sometimes not being generated on darwin. */
838 #ifdef LISP_FEATURE_DARWIN
841 sigprocmask(SIG_BLOCK, &deferrable_sigset, &oldset);
842 status = raise(signal);
843 sigprocmask(SIG_SETMASK,&oldset,0);
846 status = raise(signal);
851 lose("cannot raise signal %d, %d %s\n",
852 signal, status, strerror(errno));