boehm-gc/darwin_stop_world.c

   1 #include "private/pthread_support.h"
   2
   3 /* This probably needs more porting work to ppc64. */
   4
   5 # if defined(GC_DARWIN_THREADS)
   6
   7 /* From "Inside Mac OS X - Mach-O Runtime Architecture" published by Apple
   8    Page 49:
   9    "The space beneath the stack pointer, where a new stack frame would normally
  10    be allocated, is called the red zone. This area as shown in Figure 3-2 may
  11    be used for any purpose as long as a new stack frame does not need to be
  12    added to the stack."
  13
  14    Page 50: "If a leaf procedure's red zone usage would exceed 224 bytes, then
  15    it must set up a stack frame just like routines that call other routines."
  16 */
  17 #if defined(__ppc__)
  18 # define PPC_RED_ZONE_SIZE 224
  19 #elif defined(__ppc64__)
  20 # define PPC_RED_ZONE_SIZE 320
  21 #endif
  22
  23 /* Try to work out the right way to access thread state structure members.
  24    The structure has changed its definition in different Darwin versions.  */
  25 #if defined(__ppc__)
  26 # define THREAD_STATE ppc_thread_state_t
  27 # if defined (HAS_PPC_THREAD_STATE_R0)
  28 #  define THREAD_FLD(x) x
  29 # elif defined (HAS_PPC_THREAD_STATE___R0)
  30 #  define THREAD_FLD(x) __ ## x
  31 # else
  32 #  error can not work out how to access fields of ppc_thread_state_t
  33 # endif
  34 #elif defined(__ppc64__)
  35 # define THREAD_STATE ppc_thread_state64_t
  36 # if defined (HAS_PPC_THREAD_STATE64_R0)
  37 #  define THREAD_FLD(x) x
  38 # elif defined (HAS_PPC_THREAD_STATE64___R0)
  39 #  define THREAD_FLD(x) __ ## x
  40 # else
  41 #  error can not work out how to access fields of ppc_thread_state64_t
  42 # endif
  43 #elif defined(__i386__)
  44 # define THREAD_STATE i386_thread_state_t
  45 # if defined (HAS_I386_THREAD_STATE_EAX)
  46 #  define THREAD_FLD(x) x
  47 # elif defined (HAS_I386_THREAD_STATE___EAX)
  48 #  define THREAD_FLD(x) __ ## x
  49 # else
  50 #  error can not work out how to access fields of i386_thread_state_t
  51 # endif
  52 #else
  53 # error unknown architecture
  54 #endif
  55
  56 typedef struct StackFrame {
  57   unsigned long savedSP;
  58   unsigned long savedCR;
  59   unsigned long savedLR;
  60   unsigned long reserved[2];
  61   unsigned long savedRTOC;
  62 } StackFrame;
  63
  64 unsigned long FindTopOfStack(unsigned int stack_start) {
  65   StackFrame    *frame;
  66
  67   if (stack_start == 0) {
  68 # ifdef POWERPC
  69 #   if CPP_WORDSZ == 32
  70       __asm__ volatile("lwz     %0,0(r1)" : "=r" (frame));
  71 #   else
  72       __asm__ volatile("ld      %0,0(r1)" : "=r" (frame));
  73 #   endif
  74 # endif
  75   } else {
  76     frame = (StackFrame *)stack_start;
  77   }
  78
  79 # ifdef DEBUG_THREADS
  80     /* GC_printf1("FindTopOfStack start at sp = %p\n", frame); */
  81 # endif
  82   do {
  83     if (frame->savedSP == 0) break;
  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 & ~3) == 0) break; /* if the next LR is bogus, stop */
  92     if ((~(frame->savedLR) & ~3) == 0) break; /* ditto */
  93   } while (1);
  94
  95 # ifdef DEBUG_THREADS
  96     /* GC_printf1("FindTopOfStack finish at sp = %p\n", frame); */
  97 # endif
  98
  99   return (unsigned long)frame;
 100 }
 101
 102 #ifdef DARWIN_DONT_PARSE_STACK
 103 void GC_push_all_stacks() {
 104   int i;
 105   kern_return_t r;
 106   GC_thread p;
 107   pthread_t me;
 108   ptr_t lo, hi;
 109   THREAD_STATE state;
 110   mach_msg_type_number_t thread_state_count = MACHINE_THREAD_STATE_COUNT;
 111
 112   me = pthread_self();
 113   if (!GC_thr_initialized) GC_thr_init();
 114
 115   for(i=0;i<THREAD_TABLE_SZ;i++) {
 116     for(p=GC_threads[i];p!=0;p=p->next) {
 117       if(p -> flags & FINISHED) continue;
 118       if(pthread_equal(p->id,me)) {
 119         lo = GC_approx_sp();
 120       } else {
 121         /* Get the thread state (registers, etc) */
 122         r = thread_get_state(
 123                              p->stop_info.mach_thread,
 124                              MACHINE_THREAD_STATE,
 125                              (natural_t*)&state,
 126                              &thread_state_count);
 127         if(r != KERN_SUCCESS) ABORT("thread_get_state failed");
 128
 129         lo = (void*)(state . THREAD_FLD (r1) - PPC_RED_ZONE_SIZE);
 130
 131         GC_push_one(state . THREAD_FLD (r0));
 132         GC_push_one(state . THREAD_FLD (r2));
 133         GC_push_one(state . THREAD_FLD (r3));
 134         GC_push_one(state . THREAD_FLD (r4));
 135         GC_push_one(state . THREAD_FLD (r5));
 136         GC_push_one(state . THREAD_FLD (r6));
 137         GC_push_one(state . THREAD_FLD (r7));
 138         GC_push_one(state . THREAD_FLD (r8));
 139         GC_push_one(state . THREAD_FLD (r9));
 140         GC_push_one(state . THREAD_FLD (r10));
 141         GC_push_one(state . THREAD_FLD (r11));
 142         GC_push_one(state . THREAD_FLD (r12));
 143         GC_push_one(state . THREAD_FLD (r13));
 144         GC_push_one(state . THREAD_FLD (r14));
 145         GC_push_one(state . THREAD_FLD (r15));
 146         GC_push_one(state . THREAD_FLD (r16));
 147         GC_push_one(state . THREAD_FLD (r17));
 148         GC_push_one(state . THREAD_FLD (r18));
 149         GC_push_one(state . THREAD_FLD (r19));
 150         GC_push_one(state . THREAD_FLD (r20));
 151         GC_push_one(state . THREAD_FLD (r21));
 152         GC_push_one(state . THREAD_FLD (r22));
 153         GC_push_one(state . THREAD_FLD (r23));
 154         GC_push_one(state . THREAD_FLD (r24));
 155         GC_push_one(state . THREAD_FLD (r25));
 156         GC_push_one(state . THREAD_FLD (r26));
 157         GC_push_one(state . THREAD_FLD (r27));
 158         GC_push_one(state . THREAD_FLD (r28));
 159         GC_push_one(state . THREAD_FLD (r29));
 160         GC_push_one(state . THREAD_FLD (r30));
 161         GC_push_one(state . THREAD_FLD (r31));
 162       } /* p != me */
 163       if(p->flags & MAIN_THREAD)
 164         hi = GC_stackbottom;
 165       else
 166         hi = p->stack_end;
 167 #if DEBUG_THREADS
 168       GC_printf3("Darwin: Stack for thread 0x%lx = [%lx,%lx)\n",
 169                  (unsigned long) p -> id,
 170                  (unsigned long) lo,
 171                  (unsigned long) hi
 172                  );
 173 #endif
 174       GC_push_all_stack(lo,hi);
 175     } /* for(p=GC_threads[i]...) */
 176   } /* for(i=0;i<THREAD_TABLE_SZ...) */
 177 }
 178
 179 #else /* !DARWIN_DONT_PARSE_STACK; Use FindTopOfStack() */
 180
 181 void GC_push_all_stacks() {
 182     int i;
 183     kern_return_t r;
 184     mach_port_t me;
 185     ptr_t lo, hi;
 186     thread_act_array_t act_list = 0;
 187     mach_msg_type_number_t listcount = 0;
 188
 189     me = mach_thread_self();
 190     if (!GC_thr_initialized) GC_thr_init();
 191
 192     r = task_threads(current_task(), &act_list, &listcount);
 193     if(r != KERN_SUCCESS) ABORT("task_threads failed");
 194     for(i = 0; i < listcount; i++) {
 195       thread_act_t thread = act_list[i];
 196       if (thread == me) {
 197         lo = GC_approx_sp();
 198         hi = (ptr_t)FindTopOfStack(0);
 199       } else {
 200 #     if defined(__ppc__) || defined(__ppc64__)
 201         THREAD_STATE info;
 202         mach_msg_type_number_t outCount = THREAD_STATE_MAX;
 203         r = thread_get_state(thread, MACHINE_THREAD_STATE,
 204                              (natural_t *)&info, &outCount);
 205         if(r != KERN_SUCCESS) ABORT("task_get_state failed");
 206
 207         lo = (void*)(info . THREAD_FLD (r1) - PPC_RED_ZONE_SIZE);
 208         hi = (ptr_t)FindTopOfStack(info . THREAD_FLD (r1));
 209
 210         GC_push_one(info . THREAD_FLD (r0));
 211         GC_push_one(info . THREAD_FLD (r2));
 212         GC_push_one(info . THREAD_FLD (r3));
 213         GC_push_one(info . THREAD_FLD (r4));
 214         GC_push_one(info . THREAD_FLD (r5));
 215         GC_push_one(info . THREAD_FLD (r6));
 216         GC_push_one(info . THREAD_FLD (r7));
 217         GC_push_one(info . THREAD_FLD (r8));
 218         GC_push_one(info . THREAD_FLD (r9));
 219         GC_push_one(info . THREAD_FLD (r10));
 220         GC_push_one(info . THREAD_FLD (r11));
 221         GC_push_one(info . THREAD_FLD (r12));
 222         GC_push_one(info . THREAD_FLD (r13));
 223         GC_push_one(info . THREAD_FLD (r14));
 224         GC_push_one(info . THREAD_FLD (r15));
 225         GC_push_one(info . THREAD_FLD (r16));
 226         GC_push_one(info . THREAD_FLD (r17));
 227         GC_push_one(info . THREAD_FLD (r18));
 228         GC_push_one(info . THREAD_FLD (r19));
 229         GC_push_one(info . THREAD_FLD (r20));
 230         GC_push_one(info . THREAD_FLD (r21));
 231         GC_push_one(info . THREAD_FLD (r22));
 232         GC_push_one(info . THREAD_FLD (r23));
 233         GC_push_one(info . THREAD_FLD (r24));
 234         GC_push_one(info . THREAD_FLD (r25));
 235         GC_push_one(info . THREAD_FLD (r26));
 236         GC_push_one(info . THREAD_FLD (r27));
 237         GC_push_one(info . THREAD_FLD (r28));
 238         GC_push_one(info . THREAD_FLD (r29));
 239         GC_push_one(info . THREAD_FLD (r30));
 240         GC_push_one(info . THREAD_FLD (r31));
 241 #      else
 242         /* FIXME: Remove after testing: */
 243         WARN("This is completely untested and likely will not work\n", 0);
 244         THREAD_STATE info;
 245         mach_msg_type_number_t outCount = THREAD_STATE_MAX;
 246         r = thread_get_state(thread, MACHINE_THREAD_STATE,
 247                              (natural_t *)&info, &outCount);
 248         if(r != KERN_SUCCESS) ABORT("task_get_state failed");
 249
 250         lo = (void*)info . THREAD_FLD (esp);
 251         hi = (ptr_t)FindTopOfStack(info . THREAD_FLD (esp));
 252
 253         GC_push_one(info . THREAD_FLD (eax));
 254         GC_push_one(info . THREAD_FLD (ebx));
 255         GC_push_one(info . THREAD_FLD (ecx));
 256         GC_push_one(info . THREAD_FLD (edx));
 257         GC_push_one(info . THREAD_FLD (edi));
 258         GC_push_one(info . THREAD_FLD (esi));
 259         /* GC_push_one(info . THREAD_FLD (ebp));  */
 260         /* GC_push_one(info . THREAD_FLD (esp));  */
 261         GC_push_one(info . THREAD_FLD (ss));
 262         GC_push_one(info . THREAD_FLD (eip));
 263         GC_push_one(info . THREAD_FLD (cs));
 264         GC_push_one(info . THREAD_FLD (ds));
 265         GC_push_one(info . THREAD_FLD (es));
 266         GC_push_one(info . THREAD_FLD (fs));
 267         GC_push_one(info . THREAD_FLD (gs));
 268 #      endif /* !POWERPC */
 269       }
 270 #     if DEBUG_THREADS
 271        GC_printf3("Darwin: Stack for thread 0x%lx = [%lx,%lx)\n",
 272                   (unsigned long) thread,
 273                   (unsigned long) lo,
 274                   (unsigned long) hi
 275                  );
 276 #     endif
 277       GC_push_all_stack(lo, hi);
 278     } /* for(p=GC_threads[i]...) */
 279     vm_deallocate(current_task(), (vm_address_t)act_list, sizeof(thread_t) * listcount);
 280 }
 281 #endif /* !DARWIN_DONT_PARSE_STACK */
 282
 283 static mach_port_t GC_mach_handler_thread;
 284 static int GC_use_mach_handler_thread = 0;
 285
 286 static struct GC_mach_thread GC_mach_threads[THREAD_TABLE_SZ];
 287 static int GC_mach_threads_count;
 288
 289 void GC_stop_init() {
 290   int i;
 291
 292   for (i = 0; i < THREAD_TABLE_SZ; i++) {
 293     GC_mach_threads[i].thread = 0;
 294     GC_mach_threads[i].already_suspended = 0;
 295   }
 296   GC_mach_threads_count = 0;
 297 }
 298
 299 /* returns true if there's a thread in act_list that wasn't in old_list */
 300 int GC_suspend_thread_list(thread_act_array_t act_list, int count,
 301                            thread_act_array_t old_list, int old_count) {
 302   mach_port_t my_thread = mach_thread_self();
 303   int i, j;
 304
 305   int changed = 0;
 306
 307   for(i = 0; i < count; i++) {
 308     thread_act_t thread = act_list[i];
 309 #   if DEBUG_THREADS
 310       GC_printf1("Attempting to suspend thread %p\n", thread);
 311 #   endif
 312     /* find the current thread in the old list */
 313     int found = 0;
 314     for(j = 0; j < old_count; j++) {
 315       thread_act_t old_thread = old_list[j];
 316       if (old_thread == thread) {
 317         found = 1;
 318         break;
 319       }
 320     }
 321     if (!found) {
 322       /* add it to the GC_mach_threads list */
 323       GC_mach_threads[GC_mach_threads_count].thread = thread;
 324       /* default is not suspended */
 325       GC_mach_threads[GC_mach_threads_count].already_suspended = 0;
 326       changed = 1;
 327     }
 328
 329     if (thread != my_thread &&
 330         (!GC_use_mach_handler_thread
 331          || (GC_use_mach_handler_thread
 332              && GC_mach_handler_thread != thread))) {
 333       struct thread_basic_info info;
 334       mach_msg_type_number_t outCount = THREAD_INFO_MAX;
 335       kern_return_t kern_result = thread_info(thread, THREAD_BASIC_INFO,
 336                                 (thread_info_t)&info, &outCount);
 337       if(kern_result != KERN_SUCCESS) {
 338         /* the thread may have quit since the thread_threads () call
 339          * we mark already_suspended so it's not dealt with anymore later
 340          */
 341         if (!found) {
 342           GC_mach_threads[GC_mach_threads_count].already_suspended = TRUE;
 343           GC_mach_threads_count++;
 344         }
 345         continue;
 346       }
 347 #     if DEBUG_THREADS
 348         GC_printf2("Thread state for 0x%lx = %d\n", thread, info.run_state);
 349 #     endif
 350       if (!found) {
 351         GC_mach_threads[GC_mach_threads_count].already_suspended = info.suspend_count;
 352       }
 353       if (info.suspend_count) continue;
 354
 355 #     if DEBUG_THREADS
 356         GC_printf1("Suspending 0x%lx\n", thread);
 357 #     endif
 358       /* Suspend the thread */
 359       kern_result = thread_suspend(thread);
 360       if(kern_result != KERN_SUCCESS) {
 361         /* the thread may have quit since the thread_threads () call
 362          * we mark already_suspended so it's not dealt with anymore later
 363          */
 364         if (!found) {
 365           GC_mach_threads[GC_mach_threads_count].already_suspended = TRUE;
 366           GC_mach_threads_count++;
 367         }
 368         continue;
 369       }
 370     }
 371     if (!found) GC_mach_threads_count++;
 372   }
 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     mach_port_t my_thread = mach_thread_self();
 383     kern_return_t kern_result;
 384     thread_act_array_t act_list, prev_list;
 385     mach_msg_type_number_t listcount, prevcount;
 386
 387 #   if DEBUG_THREADS
 388       GC_printf1("Stopping the world from 0x%lx\n", mach_thread_self());
 389 #   endif
 390
 391     /* clear out the mach threads list table */
 392     GC_stop_init();
 393
 394     /* Make sure all free list construction has stopped before we start. */
 395     /* No new construction can start, since free list construction is   */
 396     /* required to acquire and release the GC lock before it starts,    */
 397     /* and we have the lock.                                            */
 398 #   ifdef PARALLEL_MARK
 399       GC_acquire_mark_lock();
 400       GC_ASSERT(GC_fl_builder_count == 0);
 401       /* We should have previously waited for it to become zero. */
 402 #   endif /* PARALLEL_MARK */
 403
 404       /* Loop stopping threads until you have gone over the whole list
 405          twice without a new one appearing. thread_create() won't
 406          return (and thus the thread stop) until the new thread
 407          exists, so there is no window whereby you could stop a
 408          thread, recognise it is stopped, but then have a new thread
 409          it created before stopping show up later.
 410       */
 411
 412       changes = 1;
 413       prev_list = NULL;
 414       prevcount = 0;
 415       do {
 416         int result;
 417         kern_result = task_threads(current_task(), &act_list, &listcount);
 418         result = GC_suspend_thread_list(act_list, listcount,
 419                                         prev_list, prevcount);
 420         changes = result;
 421         prev_list = act_list;
 422         prevcount = listcount;
 423         vm_deallocate(current_task(), (vm_address_t)act_list, sizeof(thread_t) * listcount);
 424       } while (changes);
 425
 426
 427 #   ifdef MPROTECT_VDB
 428       if(GC_incremental) {
 429         extern void GC_mprotect_stop();
 430         GC_mprotect_stop();
 431       }
 432 #   endif
 433
 434 #   ifdef PARALLEL_MARK
 435       GC_release_mark_lock();
 436 #   endif
 437     #if DEBUG_THREADS
 438       GC_printf1("World stopped from 0x%lx\n", my_thread);
 439     #endif
 440 }
 441
 442 /* Caller holds allocation lock, and has held it continuously since     */
 443 /* the world stopped.                                                   */
 444 void GC_start_world()
 445 {
 446   mach_port_t my_thread = mach_thread_self();
 447   int i, j;
 448   GC_thread p;
 449   kern_return_t kern_result;
 450   thread_act_array_t act_list;
 451   mach_msg_type_number_t listcount;
 452   struct thread_basic_info info;
 453   mach_msg_type_number_t outCount = THREAD_INFO_MAX;
 454
 455 #   if DEBUG_THREADS
 456       GC_printf0("World starting\n");
 457 #   endif
 458
 459 #   ifdef MPROTECT_VDB
 460       if(GC_incremental) {
 461         extern void GC_mprotect_resume();
 462         GC_mprotect_resume();
 463       }
 464 #   endif
 465
 466     kern_result = task_threads(current_task(), &act_list, &listcount);
 467     for(i = 0; i < listcount; i++) {
 468       thread_act_t thread = act_list[i];
 469       if (thread != my_thread &&
 470           (!GC_use_mach_handler_thread ||
 471            (GC_use_mach_handler_thread && GC_mach_handler_thread != thread))) {
 472         for(j = 0; j < GC_mach_threads_count; j++) {
 473           if (thread == GC_mach_threads[j].thread) {
 474             if (GC_mach_threads[j].already_suspended) {
 475 #             if DEBUG_THREADS
 476                 GC_printf1("Not resuming already suspended thread %p\n", thread);
 477 #             endif
 478               continue;
 479             }
 480             kern_result = thread_info(thread, THREAD_BASIC_INFO,
 481                                       (thread_info_t)&info, &outCount);
 482             if(kern_result != KERN_SUCCESS) ABORT("thread_info failed");
 483 #           if DEBUG_THREADS
 484               GC_printf2("Thread state for 0x%lx = %d\n", thread,
 485                          info.run_state);
 486               GC_printf1("Resuming 0x%lx\n", thread);
 487 #           endif
 488             /* Resume the thread */
 489             kern_result = thread_resume(thread);
 490             if(kern_result != KERN_SUCCESS) ABORT("thread_resume failed");
 491           }
 492         }
 493       }
 494     }
 495     vm_deallocate(current_task(), (vm_address_t)act_list, sizeof(thread_t) * listcount);
 496 #   if DEBUG_THREADS
 497      GC_printf0("World started\n");
 498 #   endif
 499 }
 500
 501 void GC_darwin_register_mach_handler_thread(mach_port_t thread) {
 502   GC_mach_handler_thread = thread;
 503   GC_use_mach_handler_thread = 1;
 504 }
 505
 506 #endif