libgc/darwin_stop_world.c

   1 #include "private/pthread_support.h"
   2
   3 # if defined(GC_DARWIN_THREADS)
   4
   5 /* From "Inside Mac OS X - Mach-O Runtime Architecture" published by Apple
   6    Page 49:
   7    "The space beneath the stack pointer, where a new stack frame would normally
   8    be allocated, is called the red zone. This area as shown in Figure 3-2 may
   9    be used for any purpose as long as a new stack frame does not need to be
  10    added to the stack."
  11
  12    Page 50: "If a leaf procedure's red zone usage would exceed 224 bytes, then
  13    it must set up a stack frame just like routines that call other routines."
  14 */
  15 #ifdef POWERPC
  16 # if CPP_WORDSZ == 32
  17 #   define PPC_RED_ZONE_SIZE 224
  18 # elif CPP_WORDSZ == 64
  19 #   define PPC_RED_ZONE_SIZE 320
  20 # endif
  21 #endif
  22
  23 typedef struct StackFrame {
  24   unsigned long savedSP;
  25   unsigned long savedCR;
  26   unsigned long savedLR;
  27   unsigned long reserved[2];
  28   unsigned long savedRTOC;
  29 } StackFrame;
  30
  31 unsigned long FindTopOfStack(unsigned int stack_start) {
  32   StackFrame    *frame;
  33
  34   if (stack_start == 0) {
  35 # ifdef POWERPC
  36 #   if CPP_WORDSZ == 32
  37       __asm__ volatile("lwz     %0,0(r1)" : "=r" (frame));
  38 #   else
  39       __asm__ volatile("ldz     %0,0(r1)" : "=r" (frame));
  40 #   endif
  41 # endif
  42   } else {
  43     frame = (StackFrame *)stack_start;
  44   }
  45
  46 # ifdef DEBUG_THREADS
  47     /* GC_printf1("FindTopOfStack start at sp = %p\n", frame); */
  48 # endif
  49   do {
  50     if (frame->savedSP == 0) break;
  51                 /* if there are no more stack frames, stop */
  52
  53     frame = (StackFrame*)frame->savedSP;
  54
  55     /* we do these next two checks after going to the next frame
  56        because the LR for the first stack frame in the loop
  57        is not set up on purpose, so we shouldn't check it. */
  58     if ((frame->savedLR & ~3) == 0) break; /* if the next LR is bogus, stop */
  59     if ((~(frame->savedLR) & ~3) == 0) break; /* ditto */
  60   } while (1);
  61
  62 # ifdef DEBUG_THREADS
  63     /* GC_printf1("FindTopOfStack finish at sp = %p\n", frame); */
  64 # endif
  65
  66   return (unsigned long)frame;
  67 }
  68
  69 #ifdef DARWIN_DONT_PARSE_STACK
  70 void GC_push_all_stacks() {
  71   int i;
  72   kern_return_t r;
  73   GC_thread p;
  74   pthread_t me;
  75   ptr_t lo, hi;
  76 #if defined(POWERPC)
  77   ppc_thread_state_t state;
  78   mach_msg_type_number_t thread_state_count = PPC_THREAD_STATE_COUNT;
  79 #elif defined(I386)
  80   i386_thread_state_t state;
  81   mach_msg_type_number_t thread_state_count = i386_THREAD_STATE_COUNT;
  82 #else
  83 # error FIXME for non-x86 || ppc architectures
  84   mach_msg_type_number_t thread_state_count = MACHINE_THREAD_STATE_COUNT;
  85 #endif
  86
  87   me = pthread_self();
  88   if (!GC_thr_initialized) GC_thr_init();
  89
  90   for(i=0;i<THREAD_TABLE_SZ;i++) {
  91     for(p=GC_threads[i];p!=0;p=p->next) {
  92       if(p -> flags & FINISHED) continue;
  93       if(pthread_equal(p->id,me)) {
  94         lo = GC_approx_sp();
  95       } else {
  96         /* Get the thread state (registers, etc) */
  97         r = thread_get_state(
  98                              p->stop_info.mach_thread,
  99                              GC_MACH_THREAD_STATE_FLAVOR,
 100                              (natural_t*)&state,
 101                              &thread_state_count);
 102         if(r != KERN_SUCCESS) ABORT("thread_get_state failed");
 103
 104 #if defined(I386)
 105         lo = state.esp;
 106
 107         GC_push_one(state.eax);
 108         GC_push_one(state.ebx);
 109         GC_push_one(state.ecx);
 110         GC_push_one(state.edx);
 111         GC_push_one(state.edi);
 112         GC_push_one(state.esi);
 113         GC_push_one(state.ebp);
 114 #elif defined(POWERPC)
 115         lo = (void*)(state.r1 - PPC_RED_ZONE_SIZE);
 116
 117         GC_push_one(state.r0);
 118         GC_push_one(state.r2);
 119         GC_push_one(state.r3);
 120         GC_push_one(state.r4);
 121         GC_push_one(state.r5);
 122         GC_push_one(state.r6);
 123         GC_push_one(state.r7);
 124         GC_push_one(state.r8);
 125         GC_push_one(state.r9);
 126         GC_push_one(state.r10);
 127         GC_push_one(state.r11);
 128         GC_push_one(state.r12);
 129         GC_push_one(state.r13);
 130         GC_push_one(state.r14);
 131         GC_push_one(state.r15);
 132         GC_push_one(state.r16);
 133         GC_push_one(state.r17);
 134         GC_push_one(state.r18);
 135         GC_push_one(state.r19);
 136         GC_push_one(state.r20);
 137         GC_push_one(state.r21);
 138         GC_push_one(state.r22);
 139         GC_push_one(state.r23);
 140         GC_push_one(state.r24);
 141         GC_push_one(state.r25);
 142         GC_push_one(state.r26);
 143         GC_push_one(state.r27);
 144         GC_push_one(state.r28);
 145         GC_push_one(state.r29);
 146         GC_push_one(state.r30);
 147         GC_push_one(state.r31);
 148 #else
 149 # error FIXME for non-x86 || ppc architectures
 150 #endif
 151       } /* p != me */
 152       if(p->flags & MAIN_THREAD)
 153         hi = GC_stackbottom;
 154       else
 155         hi = p->stack_end;
 156 #if DEBUG_THREADS
 157       GC_printf3("Darwin: Stack for thread 0x%lx = [%lx,%lx)\n",
 158                  (unsigned long) p -> id,
 159                  (unsigned long) lo,
 160                  (unsigned long) hi
 161                  );
 162 #endif
 163       GC_push_all_stack(lo,hi);
 164     } /* for(p=GC_threads[i]...) */
 165   } /* for(i=0;i<THREAD_TABLE_SZ...) */
 166 }
 167
 168 #else /* !DARWIN_DONT_PARSE_STACK; Use FindTopOfStack() */
 169
 170 void GC_push_all_stacks() {
 171     int i;
 172         task_t my_task;
 173     kern_return_t r;
 174     mach_port_t me;
 175     ptr_t lo, hi;
 176     thread_act_array_t act_list = 0;
 177     mach_msg_type_number_t listcount = 0;
 178
 179     me = mach_thread_self();
 180     if (!GC_thr_initialized) GC_thr_init();
 181
 182         my_task = current_task();
 183     r = task_threads(my_task, &act_list, &listcount);
 184     if(r != KERN_SUCCESS) ABORT("task_threads failed");
 185     for(i = 0; i < listcount; i++) {
 186       thread_act_t thread = act_list[i];
 187       if (thread == me) {
 188         lo = GC_approx_sp();
 189         hi = (ptr_t)FindTopOfStack(0);
 190       } else {
 191 #     if defined(POWERPC)
 192 #      if CPP_WORDSZ == 32
 193         ppc_thread_state_t info;
 194 #      else
 195         ppc_thread_state64_t info;
 196 #      endif
 197         mach_msg_type_number_t outCount = THREAD_STATE_MAX;
 198         r = thread_get_state(thread, GC_MACH_THREAD_STATE_FLAVOR,
 199                              (natural_t *)&info, &outCount);
 200         if(r != KERN_SUCCESS) continue;
 201
 202         lo = (void*)(info.r1 - PPC_RED_ZONE_SIZE);
 203         hi = (ptr_t)FindTopOfStack(info.r1);
 204
 205         GC_push_one(info.r0);
 206         GC_push_one(info.r2);
 207         GC_push_one(info.r3);
 208         GC_push_one(info.r4);
 209         GC_push_one(info.r5);
 210         GC_push_one(info.r6);
 211         GC_push_one(info.r7);
 212         GC_push_one(info.r8);
 213         GC_push_one(info.r9);
 214         GC_push_one(info.r10);
 215         GC_push_one(info.r11);
 216         GC_push_one(info.r12);
 217         GC_push_one(info.r13);
 218         GC_push_one(info.r14);
 219         GC_push_one(info.r15);
 220         GC_push_one(info.r16);
 221         GC_push_one(info.r17);
 222         GC_push_one(info.r18);
 223         GC_push_one(info.r19);
 224         GC_push_one(info.r20);
 225         GC_push_one(info.r21);
 226         GC_push_one(info.r22);
 227         GC_push_one(info.r23);
 228         GC_push_one(info.r24);
 229         GC_push_one(info.r25);
 230         GC_push_one(info.r26);
 231         GC_push_one(info.r27);
 232         GC_push_one(info.r28);
 233         GC_push_one(info.r29);
 234         GC_push_one(info.r30);
 235         GC_push_one(info.r31);
 236 #      else
 237         /* FIXME: Remove after testing: */
 238         WARN("This is completely untested and likely will not work\n", 0);
 239         i386_thread_state_t info;
 240         mach_msg_type_number_t outCount = THREAD_STATE_MAX;
 241         r = thread_get_state(thread, GC_MACH_THREAD_STATE_FLAVOR,
 242                              (natural_t *)&info, &outCount);
 243         if(r != KERN_SUCCESS) continue;
 244
 245         lo = (void*)info.esp;
 246         hi = (ptr_t)FindTopOfStack(info.esp);
 247
 248         GC_push_one(info.eax);
 249         GC_push_one(info.ebx);
 250         GC_push_one(info.ecx);
 251         GC_push_one(info.edx);
 252         GC_push_one(info.edi);
 253         GC_push_one(info.esi);
 254         /* GC_push_one(info.ebp);  */
 255         /* GC_push_one(info.esp);  */
 256         GC_push_one(info.ss);
 257         GC_push_one(info.eip);
 258         GC_push_one(info.cs);
 259         GC_push_one(info.ds);
 260         GC_push_one(info.es);
 261         GC_push_one(info.fs);
 262         GC_push_one(info.gs);
 263 #      endif /* !POWERPC */
 264       }
 265 #     if DEBUG_THREADS
 266        GC_printf3("Darwin: Stack for thread 0x%lx = [%lx,%lx)\n",
 267                   (unsigned long) thread,
 268                   (unsigned long) lo,
 269                   (unsigned long) hi
 270                  );
 271 #     endif
 272       GC_push_all_stack(lo, hi);
 273           mach_port_deallocate(my_task, thread);
 274     } /* for(p=GC_threads[i]...) */
 275     vm_deallocate(my_task, (vm_address_t)act_list, sizeof(thread_t) * listcount);
 276         mach_port_deallocate(my_task, me);
 277 }
 278 #endif /* !DARWIN_DONT_PARSE_STACK */
 279
 280 static mach_port_t GC_mach_handler_thread;
 281 static int GC_use_mach_handler_thread = 0;
 282
 283 #define SUSPEND_THREADS_SIZE 2048
 284 static struct GC_mach_thread GC_mach_threads[SUSPEND_THREADS_SIZE];
 285 static int GC_mach_threads_count;
 286
 287 void GC_stop_init() {
 288   int i;
 289
 290   for (i = 0; i < SUSPEND_THREADS_SIZE; i++) {
 291     GC_mach_threads[i].thread = 0;
 292     GC_mach_threads[i].already_suspended = 0;
 293   }
 294   GC_mach_threads_count = 0;
 295 }
 296
 297 /* returns true if there's a thread in act_list that wasn't in old_list */
 298 int GC_suspend_thread_list(thread_act_array_t act_list, int count,
 299                            thread_act_array_t old_list, int old_count) {
 300   mach_port_t my_thread = mach_thread_self();
 301   int i, j;
 302
 303   int changed = 0;
 304
 305   for(i = 0; i < count; i++) {
 306     thread_act_t thread = act_list[i];
 307 #   if DEBUG_THREADS
 308       GC_printf1("Attempting to suspend thread %p\n", thread);
 309 #   endif
 310     /* find the current thread in the old list */
 311     int found = 0;
 312     for(j = 0; j < old_count; j++) {
 313       thread_act_t old_thread = old_list[j];
 314       if (old_thread == thread) {
 315         found = 1;
 316         break;
 317       }
 318     }
 319     if (!found) {
 320       /* add it to the GC_mach_threads list */
 321       GC_mach_threads[GC_mach_threads_count].thread = thread;
 322       /* default is not suspended */
 323       GC_mach_threads[GC_mach_threads_count].already_suspended = 0;
 324       changed = 1;
 325     }
 326
 327     if (thread != my_thread &&
 328         (!GC_use_mach_handler_thread
 329          || (GC_use_mach_handler_thread
 330              && GC_mach_handler_thread != thread))) {
 331       struct thread_basic_info info;
 332       mach_msg_type_number_t outCount = THREAD_INFO_MAX;
 333       kern_return_t kern_result = thread_info(thread, THREAD_BASIC_INFO,
 334                                 (thread_info_t)&info, &outCount);
 335       if(kern_result != KERN_SUCCESS) {
 336         /* the thread may have quit since the thread_threads () call
 337          * we mark already_suspended so it's not dealt with anymore later
 338          */
 339         if (!found) {
 340           GC_mach_threads[GC_mach_threads_count].already_suspended = TRUE;
 341           GC_mach_threads_count++;
 342         }
 343         continue;
 344       }
 345 #     if DEBUG_THREADS
 346         GC_printf2("Thread state for 0x%lx = %d\n", thread, info.run_state);
 347 #     endif
 348       if (!found) {
 349         GC_mach_threads[GC_mach_threads_count].already_suspended = info.suspend_count;
 350       }
 351       if (info.suspend_count) continue;
 352
 353 #     if DEBUG_THREADS
 354         GC_printf1("Suspending 0x%lx\n", thread);
 355 #     endif
 356       /* Suspend the thread */
 357       kern_result = thread_suspend(thread);
 358       if(kern_result != KERN_SUCCESS) {
 359         /* the thread may have quit since the thread_threads () call
 360          * we mark already_suspended so it's not dealt with anymore later
 361          */
 362         if (!found) {
 363           GC_mach_threads[GC_mach_threads_count].already_suspended = TRUE;
 364           GC_mach_threads_count++;
 365         }
 366         continue;
 367       }
 368     }
 369     if (!found) GC_mach_threads_count++;
 370   }
 371
 372   mach_port_deallocate(current_task(), my_thread);
 373   return changed;
 374 }
 375
 376
 377 /* Caller holds allocation lock.        */
 378 void GC_stop_world()
 379 {
 380   int i, changes;
 381     GC_thread p;
 382         task_t my_task = current_task();
 383     mach_port_t my_thread = mach_thread_self();
 384     kern_return_t kern_result;
 385     thread_act_array_t act_list, prev_list;
 386     mach_msg_type_number_t listcount, prevcount;
 387
 388 #   if DEBUG_THREADS
 389       GC_printf1("Stopping the world from 0x%lx\n", mach_thread_self());
 390 #   endif
 391
 392     /* clear out the mach threads list table */
 393     GC_stop_init();
 394
 395     /* Make sure all free list construction has stopped before we start. */
 396     /* No new construction can start, since free list construction is   */
 397     /* required to acquire and release the GC lock before it starts,    */
 398     /* and we have the lock.                                            */
 399 #   ifdef PARALLEL_MARK
 400       GC_acquire_mark_lock();
 401       GC_ASSERT(GC_fl_builder_count == 0);
 402       /* We should have previously waited for it to become zero. */
 403 #   endif /* PARALLEL_MARK */
 404
 405       /* Loop stopping threads until you have gone over the whole list
 406          twice without a new one appearing. thread_create() won't
 407          return (and thus the thread stop) until the new thread
 408          exists, so there is no window whereby you could stop a
 409          thread, recognise it is stopped, but then have a new thread
 410          it created before stopping show up later.
 411       */
 412
 413       changes = 1;
 414       prev_list = NULL;
 415       prevcount = 0;
 416       do {
 417         int result;
 418         kern_result = task_threads(my_task, &act_list, &listcount);
 419
 420         if(kern_result == KERN_SUCCESS) {
 421                 result = GC_suspend_thread_list(act_list, listcount,
 422                                                                                 prev_list, prevcount);
 423                 changes = result;
 424
 425                 if(prev_list != NULL) {
 426                         for(i = 0; i < prevcount; i++)
 427                                 mach_port_deallocate(my_task, prev_list[i]);
 428
 429                         vm_deallocate(my_task, (vm_address_t)prev_list, sizeof(thread_t) * prevcount);
 430                 }
 431
 432                 prev_list = act_list;
 433                 prevcount = listcount;
 434         }
 435       } while (changes);
 436
 437           for(i = 0; i < listcount; i++)
 438                   mach_port_deallocate(my_task, act_list[i]);
 439
 440           vm_deallocate(my_task, (vm_address_t)act_list, sizeof(thread_t) * listcount);
 441
 442
 443 #   ifdef MPROTECT_VDB
 444       if(GC_incremental) {
 445         extern void GC_mprotect_stop();
 446         GC_mprotect_stop();
 447       }
 448 #   endif
 449
 450 #   ifdef PARALLEL_MARK
 451       GC_release_mark_lock();
 452 #   endif
 453     #if DEBUG_THREADS
 454       GC_printf1("World stopped from 0x%lx\n", my_thread);
 455     #endif
 456
 457           mach_port_deallocate(my_task, my_thread);
 458 }
 459
 460 /* Caller holds allocation lock, and has held it continuously since     */
 461 /* the world stopped.                                                   */
 462 void GC_start_world()
 463 {
 464   task_t my_task = current_task();
 465   mach_port_t my_thread = mach_thread_self();
 466   int i, j;
 467   GC_thread p;
 468   kern_return_t kern_result;
 469   thread_act_array_t act_list;
 470   mach_msg_type_number_t listcount;
 471   struct thread_basic_info info;
 472   mach_msg_type_number_t outCount = THREAD_INFO_MAX;
 473
 474 #   if DEBUG_THREADS
 475       GC_printf0("World starting\n");
 476 #   endif
 477
 478 #   ifdef MPROTECT_VDB
 479       if(GC_incremental) {
 480         extern void GC_mprotect_resume();
 481         GC_mprotect_resume();
 482       }
 483 #   endif
 484
 485     kern_result = task_threads(my_task, &act_list, &listcount);
 486     for(i = 0; i < listcount; i++) {
 487       thread_act_t thread = act_list[i];
 488       if (thread != my_thread &&
 489           (!GC_use_mach_handler_thread ||
 490            (GC_use_mach_handler_thread && GC_mach_handler_thread != thread))) {
 491         for(j = 0; j < GC_mach_threads_count; j++) {
 492           if (thread == GC_mach_threads[j].thread) {
 493             if (GC_mach_threads[j].already_suspended) {
 494 #             if DEBUG_THREADS
 495                 GC_printf1("Not resuming already suspended thread %p\n", thread);
 496 #             endif
 497               continue;
 498             }
 499             kern_result = thread_info(thread, THREAD_BASIC_INFO,
 500                                       (thread_info_t)&info, &outCount);
 501             if(kern_result != KERN_SUCCESS) continue;
 502 #           if DEBUG_THREADS
 503               GC_printf2("Thread state for 0x%lx = %d\n", thread,
 504                          info.run_state);
 505               GC_printf1("Resuming 0x%lx\n", thread);
 506 #           endif
 507             /* Resume the thread */
 508             kern_result = thread_resume(thread);
 509             if(kern_result != KERN_SUCCESS) continue;
 510           }
 511         }
 512       }
 513
 514           mach_port_deallocate(my_task, thread);
 515     }
 516     vm_deallocate(my_task, (vm_address_t)act_list, sizeof(thread_t) * listcount);
 517
 518         mach_port_deallocate(my_task, my_thread);
 519 #   if DEBUG_THREADS
 520      GC_printf0("World started\n");
 521 #   endif
 522 }
 523
 524 void GC_darwin_register_mach_handler_thread(mach_port_t thread) {
 525   GC_mach_handler_thread = thread;
 526   GC_use_mach_handler_thread = 1;
 527 }
 528
 529 #endif