1 /*
2 * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
3 * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
4 * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
5 * Copyright (c) 2000-2010 by Hewlett-Packard Development Company.
6 * All rights reserved.
7 *
8 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
9 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
10 *
11 * Permission is hereby granted to use or copy this program
12 * for any purpose, provided the above notices are retained on all copies.
13 * Permission to modify the code and to distribute modified code is granted,
14 * provided the above notices are retained, and a notice that the code was
15 * modified is included with the above copyright notice.
16 */
17
18 #include "private/pthread_support.h"
19
20 /* This probably needs more porting work to ppc64. */
21
22 #if defined(GC_DARWIN_THREADS)
23
24 #include <sys/sysctl.h>
25 #include <mach/machine.h>
26 #include <CoreFoundation/CoreFoundation.h>
27
28 /* From "Inside Mac OS X - Mach-O Runtime Architecture" published by Apple
29 Page 49:
30 "The space beneath the stack pointer, where a new stack frame would normally
31 be allocated, is called the red zone. This area as shown in Figure 3-2 may
32 be used for any purpose as long as a new stack frame does not need to be
33 added to the stack."
34
35 Page 50: "If a leaf procedure's red zone usage would exceed 224 bytes, then
36 it must set up a stack frame just like routines that call other routines."
37 */
38 #ifdef POWERPC
39 # if CPP_WORDSZ == 32
40 # define PPC_RED_ZONE_SIZE 224
41 # elif CPP_WORDSZ == 64
42 # define PPC_RED_ZONE_SIZE 320
43 # endif
44 #endif
45
46 #ifndef DARWIN_DONT_PARSE_STACK
47
48 typedef struct StackFrame {
49 unsigned long savedSP;
50 unsigned long savedCR;
51 unsigned long savedLR;
52 unsigned long reserved[2];
53 unsigned long savedRTOC;
54 } StackFrame;
55
GC_FindTopOfStack(unsigned long stack_start)56 GC_INNER ptr_t GC_FindTopOfStack(unsigned long stack_start)
57 {
58 StackFrame *frame = (StackFrame *)stack_start;
59
60 if (stack_start == 0) {
61 # ifdef POWERPC
62 # if CPP_WORDSZ == 32
63 __asm__ __volatile__ ("lwz %0,0(r1)" : "=r" (frame));
64 # else
65 __asm__ __volatile__ ("ld %0,0(r1)" : "=r" (frame));
66 # endif
67 # elif defined(ARM32)
68 volatile ptr_t sp_reg;
69 __asm__ __volatile__ ("mov %0, r7\n" : "=r" (sp_reg));
70 frame = (StackFrame *)sp_reg;
71 # elif defined(AARCH64)
72 volatile ptr_t sp_reg;
73 __asm__ __volatile__ ("mov %0, x29\n" : "=r" (sp_reg));
74 frame = (StackFrame *)sp_reg;
75 # else
76 ABORT("GC_FindTopOfStack(0) is not implemented");
77 # endif
78 }
79
80 # ifdef DEBUG_THREADS_EXTRA
81 GC_log_printf("FindTopOfStack start at sp = %p\n", (void *)frame);
82 # endif
83 while (frame->savedSP != 0) {
84 /* if there are no more stack frames, stop */
85
86 frame = (StackFrame*)frame->savedSP;
87
88 /* we do these next two checks after going to the next frame
89 because the LR for the first stack frame in the loop
90 is not set up on purpose, so we shouldn't check it. */
91 if ((frame->savedLR & ~0x3) == 0 || (frame->savedLR & ~0x3) == ~0x3UL)
92 break; /* if the next LR is bogus, stop */
93 }
94 # ifdef DEBUG_THREADS_EXTRA
95 GC_log_printf("FindTopOfStack finish at sp = %p\n", (void *)frame);
96 # endif
97 return (ptr_t)frame;
98 }
99
100 #endif /* !DARWIN_DONT_PARSE_STACK */
101
102 /* GC_query_task_threads controls whether to obtain the list of */
103 /* the threads from the kernel or to use GC_threads table. */
104 #ifdef GC_NO_THREADS_DISCOVERY
105 # define GC_query_task_threads FALSE
106 #elif defined(GC_DISCOVER_TASK_THREADS)
107 # define GC_query_task_threads TRUE
108 #else
109 STATIC GC_bool GC_query_task_threads = FALSE;
110 #endif /* !GC_NO_THREADS_DISCOVERY */
111
112 /* Use implicit threads registration (all task threads excluding the GC */
113 /* special ones are stopped and scanned). Should be called before */
114 /* GC_INIT() (or, at least, before going multi-threaded). Deprecated. */
GC_use_threads_discovery(void)115 GC_API void GC_CALL GC_use_threads_discovery(void)
116 {
117 # if defined(GC_NO_THREADS_DISCOVERY) || defined(DARWIN_DONT_PARSE_STACK)
118 ABORT("Darwin task-threads-based stop and push unsupported");
119 # else
120 # ifndef GC_ALWAYS_MULTITHREADED
121 GC_ASSERT(!GC_need_to_lock);
122 # endif
123 # ifndef GC_DISCOVER_TASK_THREADS
124 GC_query_task_threads = TRUE;
125 # endif
126 GC_init_parallel(); /* just to be consistent with Win32 one */
127 # endif
128 }
129
130 #ifndef kCFCoreFoundationVersionNumber_iOS_8_0
131 # define kCFCoreFoundationVersionNumber_iOS_8_0 1140.1
132 #endif
133
134 /* Evaluates the stack range for a given thread. Returns the lower */
135 /* bound and sets *phi to the upper one. */
GC_stack_range_for(ptr_t * phi,thread_act_t thread,GC_thread p,GC_bool thread_blocked,mach_port_t my_thread,ptr_t * paltstack_lo,ptr_t * paltstack_hi GC_ATTR_UNUSED)136 STATIC ptr_t GC_stack_range_for(ptr_t *phi, thread_act_t thread, GC_thread p,
137 GC_bool thread_blocked, mach_port_t my_thread,
138 ptr_t *paltstack_lo,
139 ptr_t *paltstack_hi GC_ATTR_UNUSED)
140 {
141 ptr_t lo;
142 if (thread == my_thread) {
143 GC_ASSERT(!thread_blocked);
144 lo = GC_approx_sp();
145 # ifndef DARWIN_DONT_PARSE_STACK
146 *phi = GC_FindTopOfStack(0);
147 # endif
148
149 } else if (thread_blocked) {
150 # if defined(CPPCHECK)
151 if (NULL == p) ABORT("Invalid GC_thread passed to GC_stack_range_for");
152 # endif
153 lo = p->stop_info.stack_ptr;
154 # ifndef DARWIN_DONT_PARSE_STACK
155 *phi = p->topOfStack;
156 # endif
157
158 } else {
159 /* MACHINE_THREAD_STATE_COUNT does not seem to be defined */
160 /* everywhere. Hence we use our own version. Alternatively, */
161 /* we could use THREAD_STATE_MAX (but seems to be not optimal). */
162 kern_return_t kern_result;
163 GC_THREAD_STATE_T state;
164
165 # if defined(ARM32) && defined(ARM_THREAD_STATE32)
166 /* Use ARM_UNIFIED_THREAD_STATE on iOS8+ 32-bit targets and on */
167 /* 64-bit H/W (iOS7+ 32-bit mode). */
168 size_t size;
169 static cpu_type_t cputype = 0;
170
171 if (cputype == 0) {
172 sysctlbyname("hw.cputype", &cputype, &size, NULL, 0);
173 }
174 if (cputype == CPU_TYPE_ARM64
175 || kCFCoreFoundationVersionNumber
176 >= kCFCoreFoundationVersionNumber_iOS_8_0) {
177 arm_unified_thread_state_t unified_state;
178 mach_msg_type_number_t unified_thread_state_count
179 = ARM_UNIFIED_THREAD_STATE_COUNT;
180 # if defined(CPPCHECK)
181 # define GC_ARM_UNIFIED_THREAD_STATE 1
182 # else
183 # define GC_ARM_UNIFIED_THREAD_STATE ARM_UNIFIED_THREAD_STATE
184 # endif
185 kern_result = thread_get_state(thread, GC_ARM_UNIFIED_THREAD_STATE,
186 (natural_t *)&unified_state,
187 &unified_thread_state_count);
188 # if !defined(CPPCHECK)
189 if (unified_state.ash.flavor != ARM_THREAD_STATE32) {
190 ABORT("unified_state flavor should be ARM_THREAD_STATE32");
191 }
192 # endif
193 state = unified_state;
194 } else
195 # endif
196 /* else */ {
197 mach_msg_type_number_t thread_state_count = GC_MACH_THREAD_STATE_COUNT;
198
199 /* Get the thread state (registers, etc.) */
200 do {
201 kern_result = thread_get_state(thread, GC_MACH_THREAD_STATE,
202 (natural_t *)&state,
203 &thread_state_count);
204 } while (kern_result == KERN_ABORTED);
205 }
206 # ifdef DEBUG_THREADS
207 GC_log_printf("thread_get_state returns value = %d\n", kern_result);
208 # endif
209 if (kern_result != KERN_SUCCESS)
210 ABORT("thread_get_state failed");
211
212 # if defined(I386)
213 lo = (ptr_t)state.THREAD_FLD(esp);
214 # ifndef DARWIN_DONT_PARSE_STACK
215 *phi = GC_FindTopOfStack(state.THREAD_FLD(esp));
216 # endif
217 GC_push_one(state.THREAD_FLD(eax));
218 GC_push_one(state.THREAD_FLD(ebx));
219 GC_push_one(state.THREAD_FLD(ecx));
220 GC_push_one(state.THREAD_FLD(edx));
221 GC_push_one(state.THREAD_FLD(edi));
222 GC_push_one(state.THREAD_FLD(esi));
223 GC_push_one(state.THREAD_FLD(ebp));
224
225 # elif defined(X86_64)
226 lo = (ptr_t)state.THREAD_FLD(rsp);
227 # ifndef DARWIN_DONT_PARSE_STACK
228 *phi = GC_FindTopOfStack(state.THREAD_FLD(rsp));
229 # endif
230 GC_push_one(state.THREAD_FLD(rax));
231 GC_push_one(state.THREAD_FLD(rbx));
232 GC_push_one(state.THREAD_FLD(rcx));
233 GC_push_one(state.THREAD_FLD(rdx));
234 GC_push_one(state.THREAD_FLD(rdi));
235 GC_push_one(state.THREAD_FLD(rsi));
236 GC_push_one(state.THREAD_FLD(rbp));
237 /* GC_push_one(state.THREAD_FLD(rsp)); */
238 GC_push_one(state.THREAD_FLD(r8));
239 GC_push_one(state.THREAD_FLD(r9));
240 GC_push_one(state.THREAD_FLD(r10));
241 GC_push_one(state.THREAD_FLD(r11));
242 GC_push_one(state.THREAD_FLD(r12));
243 GC_push_one(state.THREAD_FLD(r13));
244 GC_push_one(state.THREAD_FLD(r14));
245 GC_push_one(state.THREAD_FLD(r15));
246
247 # elif defined(POWERPC)
248 lo = (ptr_t)(state.THREAD_FLD(r1) - PPC_RED_ZONE_SIZE);
249 # ifndef DARWIN_DONT_PARSE_STACK
250 *phi = GC_FindTopOfStack(state.THREAD_FLD(r1));
251 # endif
252 GC_push_one(state.THREAD_FLD(r0));
253 GC_push_one(state.THREAD_FLD(r2));
254 GC_push_one(state.THREAD_FLD(r3));
255 GC_push_one(state.THREAD_FLD(r4));
256 GC_push_one(state.THREAD_FLD(r5));
257 GC_push_one(state.THREAD_FLD(r6));
258 GC_push_one(state.THREAD_FLD(r7));
259 GC_push_one(state.THREAD_FLD(r8));
260 GC_push_one(state.THREAD_FLD(r9));
261 GC_push_one(state.THREAD_FLD(r10));
262 GC_push_one(state.THREAD_FLD(r11));
263 GC_push_one(state.THREAD_FLD(r12));
264 GC_push_one(state.THREAD_FLD(r13));
265 GC_push_one(state.THREAD_FLD(r14));
266 GC_push_one(state.THREAD_FLD(r15));
267 GC_push_one(state.THREAD_FLD(r16));
268 GC_push_one(state.THREAD_FLD(r17));
269 GC_push_one(state.THREAD_FLD(r18));
270 GC_push_one(state.THREAD_FLD(r19));
271 GC_push_one(state.THREAD_FLD(r20));
272 GC_push_one(state.THREAD_FLD(r21));
273 GC_push_one(state.THREAD_FLD(r22));
274 GC_push_one(state.THREAD_FLD(r23));
275 GC_push_one(state.THREAD_FLD(r24));
276 GC_push_one(state.THREAD_FLD(r25));
277 GC_push_one(state.THREAD_FLD(r26));
278 GC_push_one(state.THREAD_FLD(r27));
279 GC_push_one(state.THREAD_FLD(r28));
280 GC_push_one(state.THREAD_FLD(r29));
281 GC_push_one(state.THREAD_FLD(r30));
282 GC_push_one(state.THREAD_FLD(r31));
283
284 # elif defined(ARM32)
285 lo = (ptr_t)state.THREAD_FLD(sp);
286 # ifndef DARWIN_DONT_PARSE_STACK
287 *phi = GC_FindTopOfStack(state.THREAD_FLD(r[7])); /* fp */
288 # endif
289 {
290 int j;
291 for (j = 0; j < 7; j++)
292 GC_push_one(state.THREAD_FLD(r[j]));
293 j++; /* "r7" is skipped (iOS uses it as a frame pointer) */
294 for (; j <= 12; j++)
295 GC_push_one(state.THREAD_FLD(r[j]));
296 }
297 /* "cpsr", "pc" and "sp" are skipped */
298 GC_push_one(state.THREAD_FLD(lr));
299
300 # elif defined(AARCH64)
301 lo = (ptr_t)state.THREAD_FLD(sp);
302 # ifndef DARWIN_DONT_PARSE_STACK
303 *phi = GC_FindTopOfStack(state.THREAD_FLD(fp));
304 # endif
305 {
306 int j;
307 for (j = 0; j <= 28; j++) {
308 GC_push_one(state.THREAD_FLD(x[j]));
309 }
310 }
311 /* "cpsr", "fp", "pc" and "sp" are skipped */
312 GC_push_one(state.THREAD_FLD(lr));
313
314 # elif defined(CPPCHECK)
315 lo = NULL;
316 # else
317 # error FIXME for non-arm/ppc/x86 architectures
318 # endif
319 } /* thread != my_thread */
320
321 # ifdef DARWIN_DONT_PARSE_STACK
322 /* p is guaranteed to be non-NULL regardless of GC_query_task_threads. */
323 *phi = (p->flags & MAIN_THREAD) != 0 ? GC_stackbottom : p->stack_end;
324 # endif
325
326 /* TODO: Determine p and handle altstack if !DARWIN_DONT_PARSE_STACK */
327 # ifdef DARWIN_DONT_PARSE_STACK
328 if (p->altstack != NULL && (word)p->altstack <= (word)lo
329 && (word)lo <= (word)p->altstack + p->altstack_size) {
330 *paltstack_lo = lo;
331 *paltstack_hi = p->altstack + p->altstack_size;
332 lo = p->stack;
333 *phi = p->stack + p->stack_size;
334 } else
335 # endif
336 /* else */ {
337 *paltstack_lo = NULL;
338 }
339 # ifdef DEBUG_THREADS
340 GC_log_printf("Darwin: Stack for thread %p = [%p,%p)\n",
341 (void *)(word)thread, (void *)lo, (void *)(*phi));
342 # endif
343 return lo;
344 }
345
GC_push_all_stacks(void)346 GC_INNER void GC_push_all_stacks(void)
347 {
348 ptr_t hi, altstack_lo, altstack_hi;
349 task_t my_task = current_task();
350 mach_port_t my_thread = mach_thread_self();
351 GC_bool found_me = FALSE;
352 int nthreads = 0;
353 word total_size = 0;
354 mach_msg_type_number_t listcount = (mach_msg_type_number_t)THREAD_TABLE_SZ;
355 if (!EXPECT(GC_thr_initialized, TRUE))
356 GC_thr_init();
357
358 # ifndef DARWIN_DONT_PARSE_STACK
359 if (GC_query_task_threads) {
360 int i;
361 kern_return_t kern_result;
362 thread_act_array_t act_list = 0;
363
364 /* Obtain the list of the threads from the kernel. */
365 kern_result = task_threads(my_task, &act_list, &listcount);
366 if (kern_result != KERN_SUCCESS)
367 ABORT("task_threads failed");
368
369 for (i = 0; i < (int)listcount; i++) {
370 thread_act_t thread = act_list[i];
371 ptr_t lo = GC_stack_range_for(&hi, thread, NULL, FALSE, my_thread,
372 &altstack_lo, &altstack_hi);
373
374 if (lo) {
375 GC_ASSERT((word)lo <= (word)hi);
376 total_size += hi - lo;
377 GC_push_all_stack(lo, hi);
378 }
379 /* TODO: Handle altstack */
380 nthreads++;
381 if (thread == my_thread)
382 found_me = TRUE;
383 mach_port_deallocate(my_task, thread);
384 } /* for (i=0; ...) */
385
386 vm_deallocate(my_task, (vm_address_t)act_list,
387 sizeof(thread_t) * listcount);
388 } else
389 # endif /* !DARWIN_DONT_PARSE_STACK */
390 /* else */ {
391 int i;
392
393 for (i = 0; i < (int)listcount; i++) {
394 GC_thread p;
395
396 for (p = GC_threads[i]; p != NULL; p = p->next)
397 if ((p->flags & FINISHED) == 0) {
398 thread_act_t thread = (thread_act_t)p->stop_info.mach_thread;
399 ptr_t lo = GC_stack_range_for(&hi, thread, p,
400 (GC_bool)p->thread_blocked,
401 my_thread, &altstack_lo,
402 &altstack_hi);
403
404 if (lo) {
405 GC_ASSERT((word)lo <= (word)hi);
406 total_size += hi - lo;
407 GC_push_all_stack_sections(lo, hi, p->traced_stack_sect);
408 }
409 if (altstack_lo) {
410 total_size += altstack_hi - altstack_lo;
411 GC_push_all_stack(altstack_lo, altstack_hi);
412 }
413 nthreads++;
414 if (thread == my_thread)
415 found_me = TRUE;
416 }
417 } /* for (i=0; ...) */
418 }
419
420 mach_port_deallocate(my_task, my_thread);
421 GC_VERBOSE_LOG_PRINTF("Pushed %d thread stacks\n", nthreads);
422 if (!found_me && !GC_in_thread_creation)
423 ABORT("Collecting from unknown thread");
424 GC_total_stacksize = total_size;
425 }
426
427 #ifndef GC_NO_THREADS_DISCOVERY
428
429 # ifdef MPROTECT_VDB
430 STATIC mach_port_t GC_mach_handler_thread = 0;
431 STATIC GC_bool GC_use_mach_handler_thread = FALSE;
432
GC_darwin_register_mach_handler_thread(mach_port_t thread)433 GC_INNER void GC_darwin_register_mach_handler_thread(mach_port_t thread)
434 {
435 GC_mach_handler_thread = thread;
436 GC_use_mach_handler_thread = TRUE;
437 }
438 # endif /* MPROTECT_VDB */
439
440 # ifndef GC_MAX_MACH_THREADS
441 # define GC_MAX_MACH_THREADS THREAD_TABLE_SZ
442 # endif
443
444 struct GC_mach_thread {
445 thread_act_t thread;
446 GC_bool suspended;
447 };
448
449 struct GC_mach_thread GC_mach_threads[GC_MAX_MACH_THREADS];
450 STATIC int GC_mach_threads_count = 0;
451 /* FIXME: it is better to implement GC_mach_threads as a hash set. */
452
453 /* returns true if there's a thread in act_list that wasn't in old_list */
GC_suspend_thread_list(thread_act_array_t act_list,int count,thread_act_array_t old_list,int old_count,task_t my_task,mach_port_t my_thread)454 STATIC GC_bool GC_suspend_thread_list(thread_act_array_t act_list, int count,
455 thread_act_array_t old_list,
456 int old_count, task_t my_task,
457 mach_port_t my_thread)
458 {
459 int i;
460 int j = -1;
461 GC_bool changed = FALSE;
462
463 for (i = 0; i < count; i++) {
464 thread_act_t thread = act_list[i];
465 GC_bool found;
466 kern_return_t kern_result;
467
468 if (thread == my_thread
469 # ifdef MPROTECT_VDB
470 || (GC_mach_handler_thread == thread && GC_use_mach_handler_thread)
471 # endif
472 # ifdef PARALLEL_MARK
473 || GC_is_mach_marker(thread) /* ignore the parallel markers */
474 # endif
475 ) {
476 /* Do not add our one, parallel marker and the handler threads; */
477 /* consider it as found (e.g., it was processed earlier). */
478 mach_port_deallocate(my_task, thread);
479 continue;
480 }
481
482 /* find the current thread in the old list */
483 found = FALSE;
484 {
485 int last_found = j; /* remember the previous found thread index */
486
487 /* Search for the thread starting from the last found one first. */
488 while (++j < old_count)
489 if (old_list[j] == thread) {
490 found = TRUE;
491 break;
492 }
493 if (!found) {
494 /* If not found, search in the rest (beginning) of the list. */
495 for (j = 0; j < last_found; j++)
496 if (old_list[j] == thread) {
497 found = TRUE;
498 break;
499 }
500 }
501 }
502
503 if (found) {
504 /* It is already in the list, skip processing, release mach port. */
505 mach_port_deallocate(my_task, thread);
506 continue;
507 }
508
509 /* add it to the GC_mach_threads list */
510 if (GC_mach_threads_count == GC_MAX_MACH_THREADS)
511 ABORT("Too many threads");
512 GC_mach_threads[GC_mach_threads_count].thread = thread;
513 /* default is not suspended */
514 GC_mach_threads[GC_mach_threads_count].suspended = FALSE;
515 changed = TRUE;
516
517 # ifdef DEBUG_THREADS
518 GC_log_printf("Suspending %p\n", (void *)(word)thread);
519 # endif
520 /* Unconditionally suspend the thread. It will do no */
521 /* harm if it is already suspended by the client logic. */
522 GC_acquire_dirty_lock();
523 do {
524 kern_result = thread_suspend(thread);
525 } while (kern_result == KERN_ABORTED);
526 GC_release_dirty_lock();
527 if (kern_result != KERN_SUCCESS) {
528 /* The thread may have quit since the thread_threads() call we */
529 /* mark already suspended so it's not dealt with anymore later. */
530 GC_mach_threads[GC_mach_threads_count].suspended = FALSE;
531 } else {
532 /* Mark the thread as suspended and require resume. */
533 GC_mach_threads[GC_mach_threads_count].suspended = TRUE;
534 if (GC_on_thread_event)
535 GC_on_thread_event(GC_EVENT_THREAD_SUSPENDED, (void *)(word)thread);
536 }
537 GC_mach_threads_count++;
538 }
539 return changed;
540 }
541
542 #endif /* !GC_NO_THREADS_DISCOVERY */
543
544 /* Caller holds allocation lock. */
GC_stop_world(void)545 GC_INNER void GC_stop_world(void)
546 {
547 task_t my_task = current_task();
548 mach_port_t my_thread = mach_thread_self();
549 kern_return_t kern_result;
550
551 # ifdef DEBUG_THREADS
552 GC_log_printf("Stopping the world from thread %p\n",
553 (void *)(word)my_thread);
554 # endif
555 # ifdef PARALLEL_MARK
556 if (GC_parallel) {
557 /* Make sure all free list construction has stopped before we */
558 /* start. No new construction can start, since free list */
559 /* construction is required to acquire and release the GC lock */
560 /* before it starts, and we have the lock. */
561 GC_acquire_mark_lock();
562 GC_ASSERT(GC_fl_builder_count == 0);
563 /* We should have previously waited for it to become zero. */
564 }
565 # endif /* PARALLEL_MARK */
566
567 if (GC_query_task_threads) {
568 # ifndef GC_NO_THREADS_DISCOVERY
569 GC_bool changed;
570 thread_act_array_t act_list, prev_list;
571 mach_msg_type_number_t listcount, prevcount;
572
573 /* Clear out the mach threads list table. We do not need to */
574 /* really clear GC_mach_threads[] as it is used only in the range */
575 /* from 0 to GC_mach_threads_count-1, inclusive. */
576 GC_mach_threads_count = 0;
577
578 /* Loop stopping threads until you have gone over the whole list */
579 /* twice without a new one appearing. thread_create() won't */
580 /* return (and thus the thread stop) until the new thread exists, */
581 /* so there is no window whereby you could stop a thread, */
582 /* recognize it is stopped, but then have a new thread it created */
583 /* before stopping show up later. */
584 changed = TRUE;
585 prev_list = NULL;
586 prevcount = 0;
587 do {
588 kern_result = task_threads(my_task, &act_list, &listcount);
589
590 if (kern_result == KERN_SUCCESS) {
591 changed = GC_suspend_thread_list(act_list, listcount, prev_list,
592 prevcount, my_task, my_thread);
593
594 if (prev_list != NULL) {
595 /* Thread ports are not deallocated by list, unused ports */
596 /* deallocated in GC_suspend_thread_list, used - kept in */
597 /* GC_mach_threads till GC_start_world as otherwise thread */
598 /* object change can occur and GC_start_world will not */
599 /* find the thread to resume which will cause app to hang. */
600 vm_deallocate(my_task, (vm_address_t)prev_list,
601 sizeof(thread_t) * prevcount);
602 }
603
604 /* Repeat while having changes. */
605 prev_list = act_list;
606 prevcount = listcount;
607 }
608 } while (changed);
609
610 GC_ASSERT(prev_list != 0);
611 /* The thread ports are not deallocated by list, see above. */
612 vm_deallocate(my_task, (vm_address_t)act_list,
613 sizeof(thread_t) * listcount);
614 # endif /* !GC_NO_THREADS_DISCOVERY */
615
616 } else {
617 unsigned i;
618
619 for (i = 0; i < THREAD_TABLE_SZ; i++) {
620 GC_thread p;
621
622 for (p = GC_threads[i]; p != NULL; p = p->next) {
623 if ((p->flags & FINISHED) == 0 && !p->thread_blocked &&
624 p->stop_info.mach_thread != my_thread) {
625 GC_acquire_dirty_lock();
626 do {
627 kern_result = thread_suspend(p->stop_info.mach_thread);
628 } while (kern_result == KERN_ABORTED);
629 GC_release_dirty_lock();
630 if (kern_result != KERN_SUCCESS)
631 ABORT("thread_suspend failed");
632 if (GC_on_thread_event)
633 GC_on_thread_event(GC_EVENT_THREAD_SUSPENDED,
634 (void *)(word)p->stop_info.mach_thread);
635 }
636 }
637 }
638 }
639
640 # ifdef MPROTECT_VDB
641 if (GC_auto_incremental) {
642 GC_mprotect_stop();
643 }
644 # endif
645 # ifdef PARALLEL_MARK
646 if (GC_parallel)
647 GC_release_mark_lock();
648 # endif
649
650 # ifdef DEBUG_THREADS
651 GC_log_printf("World stopped from %p\n", (void *)(word)my_thread);
652 # endif
653 mach_port_deallocate(my_task, my_thread);
654 }
655
GC_thread_resume(thread_act_t thread)656 GC_INLINE void GC_thread_resume(thread_act_t thread)
657 {
658 kern_return_t kern_result;
659 # if defined(DEBUG_THREADS) || defined(GC_ASSERTIONS)
660 struct thread_basic_info info;
661 mach_msg_type_number_t outCount = THREAD_BASIC_INFO_COUNT;
662
663 kern_result = thread_info(thread, THREAD_BASIC_INFO,
664 (thread_info_t)&info, &outCount);
665 if (kern_result != KERN_SUCCESS)
666 ABORT("thread_info failed");
667 # endif
668 # ifdef DEBUG_THREADS
669 GC_log_printf("Resuming thread %p with state %d\n", (void *)(word)thread,
670 info.run_state);
671 # endif
672 /* Resume the thread */
673 kern_result = thread_resume(thread);
674 if (kern_result != KERN_SUCCESS) {
675 WARN("thread_resume(%p) failed: mach port invalid\n", thread);
676 } else if (GC_on_thread_event) {
677 GC_on_thread_event(GC_EVENT_THREAD_UNSUSPENDED, (void *)(word)thread);
678 }
679 }
680
681 /* Caller holds allocation lock, and has held it continuously since */
682 /* the world stopped. */
GC_start_world(void)683 GC_INNER void GC_start_world(void)
684 {
685 task_t my_task = current_task();
686 # ifdef DEBUG_THREADS
687 GC_log_printf("World starting\n");
688 # endif
689 # ifdef MPROTECT_VDB
690 if (GC_auto_incremental) {
691 GC_mprotect_resume();
692 }
693 # endif
694
695 if (GC_query_task_threads) {
696 # ifndef GC_NO_THREADS_DISCOVERY
697 int i, j;
698 kern_return_t kern_result;
699 thread_act_array_t act_list;
700 mach_msg_type_number_t listcount;
701
702 kern_result = task_threads(my_task, &act_list, &listcount);
703 if (kern_result != KERN_SUCCESS)
704 ABORT("task_threads failed");
705
706 j = (int)listcount;
707 for (i = 0; i < GC_mach_threads_count; i++) {
708 thread_act_t thread = GC_mach_threads[i].thread;
709
710 if (GC_mach_threads[i].suspended) {
711 int last_found = j; /* The thread index found during the */
712 /* previous iteration (count value */
713 /* means no thread found yet). */
714
715 /* Search for the thread starting from the last found one first. */
716 while (++j < (int)listcount) {
717 if (act_list[j] == thread)
718 break;
719 }
720 if (j >= (int)listcount) {
721 /* If not found, search in the rest (beginning) of the list. */
722 for (j = 0; j < last_found; j++) {
723 if (act_list[j] == thread)
724 break;
725 }
726 }
727 if (j != last_found) {
728 /* The thread is alive, resume it. */
729 GC_thread_resume(thread);
730 }
731 } else {
732 /* This thread was failed to be suspended by GC_stop_world, */
733 /* no action needed. */
734 # ifdef DEBUG_THREADS
735 GC_log_printf("Not resuming thread %p as it is not suspended\n",
736 (void *)(word)thread);
737 # endif
738 }
739 mach_port_deallocate(my_task, thread);
740 }
741
742 for (i = 0; i < (int)listcount; i++)
743 mach_port_deallocate(my_task, act_list[i]);
744 vm_deallocate(my_task, (vm_address_t)act_list,
745 sizeof(thread_t) * listcount);
746 # endif /* !GC_NO_THREADS_DISCOVERY */
747
748 } else {
749 int i;
750 mach_port_t my_thread = mach_thread_self();
751
752 for (i = 0; i < THREAD_TABLE_SZ; i++) {
753 GC_thread p;
754 for (p = GC_threads[i]; p != NULL; p = p->next) {
755 if ((p->flags & FINISHED) == 0 && !p->thread_blocked &&
756 p->stop_info.mach_thread != my_thread)
757 GC_thread_resume(p->stop_info.mach_thread);
758 }
759 }
760
761 mach_port_deallocate(my_task, my_thread);
762 }
763
764 # ifdef DEBUG_THREADS
765 GC_log_printf("World started\n");
766 # endif
767 }
768
769 #endif /* GC_DARWIN_THREADS */
770