solaris_threads.c

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		return NULL;
	}

        base = (ptr_t)(((word)base + GC_page_size) & ~(GC_page_size - 1));
        /* Protect hottest page to detect overflow. */
#	ifdef SOLARIS23_MPROTECT_BUG_FIXED
            mprotect(base, GC_page_size, PROT_NONE);
#	endif
        GC_is_fresh((struct hblk *)base, divHBLKSZ(search_sz));

        base += GC_page_size;
#endif
    }
    *stack_size = search_sz;
    return(base);
}

/* Caller holds  allocationlock.					*/
void GC_stack_free(ptr_t stack, size_t size)
{
    register int index = 0;
    register size_t search_sz = GC_min_stack_sz;
    register struct stack_head *head;
    
#ifdef MMAP_STACKS
    /* Zero pointers */
    mmap(stack, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_NORESERVE|MAP_FIXED,
	 GC_zfd, 0);
#endif
    while (search_sz < size) {
        search_sz *= 2;
        index++;
    }
    if (search_sz != size) ABORT("Bad stack size");

    head = (struct stack_head *)(stack + search_sz - sizeof(struct stack_head));
    head->next = GC_stack_free_lists[index];
    head->base = stack;
    GC_stack_free_lists[index] = head;
}

void GC_my_stack_limits();

/* Notify virtual dirty bit implementation that known empty parts of	*/
/* stacks do not contain useful data.					*/ 
/* Caller holds allocation lock.					*/
void GC_old_stacks_are_fresh()
{
/* No point in doing this for MMAP stacks - and pointers are zero'd out */
/* by the mmap in GC_stack_free */
#ifndef MMAP_STACKS
    register int i;
    register struct stack_head *s;
    register ptr_t p;
    register size_t sz;
    register struct hblk * h;
    int dummy;
    
    for (i = 0, sz= GC_min_stack_sz; i < N_FREE_LISTS;
         i++, sz *= 2) {
         for (s = GC_stack_free_lists[i]; s != 0; s = s->next) {
             p = s->base;
             h = (struct hblk *)(((word)p + HBLKSIZE-1) & ~(HBLKSIZE-1));
             if ((ptr_t)h == p) {
                 GC_is_fresh((struct hblk *)p, divHBLKSZ(sz));
             } else {
                 GC_is_fresh((struct hblk *)p, divHBLKSZ(sz) - 1);
                 BZERO(p, (ptr_t)h - p);
             }
         }
    }
#endif /* MMAP_STACKS */
    GC_my_stack_limits();
}

/* The set of all known threads.  We intercept thread creation and 	*/
/* joins.  We never actually create detached threads.  We allocate all 	*/
/* new thread stacks ourselves.  These allow us to maintain this	*/
/* data structure.							*/

# define THREAD_TABLE_SZ 128	/* Must be power of 2	*/
volatile GC_thread GC_threads[THREAD_TABLE_SZ];

void GC_push_thread_structures GC_PROTO((void))
{
    GC_push_all((ptr_t)(GC_threads), (ptr_t)(GC_threads)+sizeof(GC_threads));
}

/* Add a thread to GC_threads.  We assume it wasn't already there.	*/
/* Caller holds allocation lock.					*/
GC_thread GC_new_thread(thread_t id)
{
    int hv = ((word)id) % THREAD_TABLE_SZ;
    GC_thread result;
    static struct GC_Thread_Rep first_thread;
    static GC_bool first_thread_used = FALSE;
    
    if (!first_thread_used) {
    	result = &first_thread;
    	first_thread_used = TRUE;
    	/* Dont acquire allocation lock, since we may already hold it. */
    } else {
        result = (struct GC_Thread_Rep *)
        	 GC_INTERNAL_MALLOC(sizeof(struct GC_Thread_Rep), NORMAL);
    }
    if (result == 0) return(0);
    result -> id = id;
    result -> next = GC_threads[hv];
    GC_threads[hv] = result;
    /* result -> finished = 0; */
    (void) cond_init(&(result->join_cv), USYNC_THREAD, 0);
    return(result);
}

/* Delete a thread from GC_threads.  We assume it is there.	*/
/* (The code intentionally traps if it wasn't.)			*/
/* Caller holds allocation lock.				*/
void GC_delete_thread(thread_t id)
{
    int hv = ((word)id) % THREAD_TABLE_SZ;
    register GC_thread p = GC_threads[hv];
    register GC_thread prev = 0;
    
    while (p -> id != id) {
        prev = p;
        p = p -> next;
    }
    if (prev == 0) {
        GC_threads[hv] = p -> next;
    } else {
        prev -> next = p -> next;
    }
}

/* Return the GC_thread correpsonding to a given thread_t.	*/
/* Returns 0 if it's not there.					*/
/* Caller holds  allocation lock.				*/
GC_thread GC_lookup_thread(thread_t id)
{
    int hv = ((word)id) % THREAD_TABLE_SZ;
    register GC_thread p = GC_threads[hv];
    
    while (p != 0 && p -> id != id) p = p -> next;
    return(p);
}

/* Solaris 2/Intel uses an initial stack size limit slightly bigger than the
   SPARC default of 8 MB.  Account for this to warn only if the user has
   raised the limit beyond the default.

   This is identical to DFLSSIZ defined in <sys/vm_machparam.h>.  This file
   is installed in /usr/platform/`uname -m`/include, which is not in the
   default include directory list, so copy the definition here.  */
#ifdef I386
# define MAX_ORIG_STACK_SIZE (8 * 1024 * 1024 + ((USRSTACK) & 0x3FFFFF))
#else
# define MAX_ORIG_STACK_SIZE (8 * 1024 * 1024)
#endif

word GC_get_orig_stack_size() {
    struct rlimit rl;
    static int warned = 0;
    int result;

    if (getrlimit(RLIMIT_STACK, &rl) != 0) ABORT("getrlimit failed");
    result = (word)rl.rlim_cur & ~(HBLKSIZE-1);
    if (result > MAX_ORIG_STACK_SIZE) {
	if (!warned) {
	    WARN("Large stack limit(%ld): only scanning 8 MB\n", result);
	    warned = 1;
	}
	result = MAX_ORIG_STACK_SIZE;
    }
    return result;
}

/* Notify dirty bit implementation of unused parts of my stack. */
/* Caller holds allocation lock.				*/
void GC_my_stack_limits()
{
    int dummy;
    register ptr_t hottest = (ptr_t)((word)(&dummy) & ~(HBLKSIZE-1));
    register GC_thread me = GC_lookup_thread(thr_self());
    register size_t stack_size = me -> stack_size;
    register ptr_t stack;
    
    if (stack_size == 0) {
      /* original thread */
        /* Empirically, what should be the stack page with lowest	*/
        /* address is actually inaccessible.				*/
        stack_size = GC_get_orig_stack_size() - GC_page_size;
        stack = GC_stackbottom - stack_size + GC_page_size;
    } else {
        stack = me -> stack;
    }
    if (stack > hottest || stack + stack_size < hottest) {
    	ABORT("sp out of bounds");
    }
    GC_is_fresh((struct hblk *)stack, divHBLKSZ(hottest - stack));
}


/* We hold allocation lock.  Should do exactly the right thing if the	*/
/* world is stopped.  Should not fail if it isn't.			*/
void GC_push_all_stacks()
{
    register int i;
    register GC_thread p;
    register ptr_t sp = GC_approx_sp();
    register ptr_t bottom, top;
    struct rlimit rl;
    
#   define PUSH(bottom,top) \
      if (GC_dirty_maintained) { \
	GC_push_selected((bottom), (top), GC_page_was_ever_dirty, \
		      GC_push_all_stack); \
      } else { \
        GC_push_all_stack((bottom), (top)); \
      }
    GC_push_all_stack((ptr_t)GC_lwp_registers,
		      (ptr_t)GC_lwp_registers
		      + max_lwps * sizeof(GC_lwp_registers[0]));
    for (i = 0; i < THREAD_TABLE_SZ; i++) {
      for (p = GC_threads[i]; p != 0; p = p -> next) {
        if (p -> stack_size != 0) {
            bottom = p -> stack;
            top = p -> stack + p -> stack_size;
        } else {
            /* The original stack. */
            bottom = GC_stackbottom - GC_get_orig_stack_size() + GC_page_size;
            top = GC_stackbottom;
        }
        if ((word)sp > (word)bottom && (word)sp < (word)top) bottom = sp;
        PUSH(bottom, top);
      }
    }
}


int GC_is_thread_stack(ptr_t addr)
{
    register int i;
    register GC_thread p;
    register ptr_t bottom, top;
    
    for (i = 0; i < THREAD_TABLE_SZ; i++) {
      for (p = GC_threads[i]; p != 0; p = p -> next) {
        if (p -> stack_size != 0) {
            if (p -> stack <= addr &&
		addr < p -> stack + p -> stack_size)
		    return 1;
	}
      }
    }
    return 0;
}

/* The only thread that ever really performs a thr_join.	*/
void * GC_thr_daemon(void * dummy)
{
    void *status;
    thread_t departed;
    register GC_thread t;
    register int i;
    register int result;
    
    for(;;) {
      start:
        result = thr_join((thread_t)0, &departed, &status);
    	LOCK();
    	if (result != 0) {
    	    /* No more threads; wait for create. */
    	    for (i = 0; i < THREAD_TABLE_SZ; i++) {
    	        for (t = GC_threads[i]; t != 0; t = t -> next) {
                    if (!(t -> flags & (DETACHED | FINISHED))) {
                      UNLOCK();
                      goto start; /* Thread started just before we */
                      		  /* acquired the lock.		   */
                    }
                }
            }
            cond_wait(&GC_create_cv, &GC_allocate_ml);
            UNLOCK();
    	} else {
    	    t = GC_lookup_thread(departed);
	    GC_multithreaded--;
    	    if (!(t -> flags & CLIENT_OWNS_STACK)) {
    	    	GC_stack_free(t -> stack, t -> stack_size);
    	    }
    	    if (t -> flags & DETACHED) {
    	    	GC_delete_thread(departed);
    	    } else {
    	        t -> status = status;
    	    	t -> flags |= FINISHED;
    	    	cond_signal(&(t -> join_cv));
    	    	cond_broadcast(&GC_prom_join_cv);
    	    }
    	    UNLOCK();
    	}
    }
}

/* We hold the allocation lock, or caller ensures that 2 instances	*/
/* cannot be invoked concurrently.					*/
void GC_thr_init(void)
{
    GC_thread t;
    thread_t tid;
    int ret;

    if (GC_thr_initialized)
	    return;
    GC_thr_initialized = TRUE;
    GC_min_stack_sz = ((thr_min_stack() + 32*1024 + HBLKSIZE-1)
    		       & ~(HBLKSIZE - 1));
#ifdef MMAP_STACKS
    GC_zfd = open("/dev/zero", O_RDONLY);
    if (GC_zfd == -1)
	    ABORT("Can't open /dev/zero");
#endif /* MMAP_STACKS */
    cond_init(&GC_prom_join_cv, USYNC_THREAD, 0);
    cond_init(&GC_create_cv, USYNC_THREAD, 0);
    /* Add the initial thread, so we can stop it.	*/
      t = GC_new_thread(thr_self());
      t -> stack_size = 0;
      t -> flags = DETACHED | CLIENT_OWNS_STACK;
    ret = thr_create(0 /* stack */, 0 /* stack_size */, GC_thr_daemon,
    		     0 /* arg */, THR_DETACHED | THR_DAEMON,
    		     &tid /* thread_id */);
    if (ret != 0) {
	GC_err_printf1("Thr_create returned %ld\n", ret);
    	ABORT("Cant fork daemon");
    }
    thr_setprio(tid, 126);
}

/* We acquire the allocation lock to prevent races with 	*/
/* stopping/starting world.					*/
/* This is no more correct than the underlying Solaris 2.X	*/
/* implementation.  Under 2.3 THIS IS BROKEN.			*/
int GC_thr_suspend(thread_t target_thread)
{
    GC_thread t;
    int result;
    
    LOCK();
    result = thr_suspend(target_thread);
    if (result == 0) {
    	t = GC_lookup_thread(target_thread);
    	if (t == 0) ABORT("thread unknown to GC");
        t -> flags |= SUSPNDED;
    }
    UNLOCK();
    return(result);
}

int GC_thr_continue(thread_t target_thread)
{
    GC_thread t;
    int result;
    
    LOCK();
    result = thr_continue(target_thread);
    if (result == 0) {
    	t = GC_lookup_thread(target_thread);
    	if (t == 0) ABORT("thread unknown to GC");
        t -> flags &= ~SUSPNDED;
    }
    UNLOCK();
    return(result);
}

int GC_thr_join(thread_t wait_for, thread_t *departed, void **status)
{
    register GC_thread t;
    int result = 0;
    
    LOCK();
    if (wait_for == 0) {
        register int i;
        register GC_bool thread_exists;
    
    	for (;;) {
    	  thread_exists = FALSE;
    	  for (i = 0; i < THREAD_TABLE_SZ; i++) {
    	    for (t = GC_threads[i]; t != 0; t = t -> next) {
              if (!(t -> flags & DETACHED)) {
                if (t -> flags & FINISHED) {
                  goto found;
                }
                thread_exists = TRUE;
              }
            }
          }
          if (!thread_exists) {
              result = ESRCH;
    	      goto out;
          }
          cond_wait(&GC_prom_join_cv, &GC_allocate_ml);
        }
    } else {
        t = GC_lookup_thread(wait_for);
    	if (t == 0 || t -> flags & DETACHED) {
    	    result = ESRCH;
    	    goto out;
    	}
    	if (wait_for == thr_self()) {
    	    result = EDEADLK;
    	    goto out;
    	}
    	while (!(t -> flags & FINISHED)) {
            cond_wait(&(t -> join_cv), &GC_allocate_ml);
    	}
    	
    }
  found:
    if (status) *status = t -> status;
    if (departed) *departed = t -> id;
    cond_destroy(&(t -> join_cv));
    GC_delete_thread(t -> id);
  out:
    UNLOCK();
    return(result);
}


int
GC_thr_create(void *stack_base, size_t stack_size,
              void *(*start_routine)(void *), void *arg, long flags,
              thread_t *new_thread)
{
    int result;
    GC_thread t;
    thread_t my_new_thread;
    word my_flags = 0;
    void * stack = stack_base;
   
    LOCK();
    if (!GC_is_initialized) GC_init_inner();
    GC_multithreaded++;
    if (stack == 0) {
     	if (stack_size == 0) stack_size = 1024*1024;
     	stack = (void *)GC_stack_alloc(&stack_size);
     	if (stack == 0) {
	    GC_multithreaded--;
     	    UNLOCK();
     	    return(ENOMEM);
     	}
    } else {
    	my_flags |= CLIENT_OWNS_STACK;
    }
    if (flags & THR_DETACHED) my_flags |= DETACHED;
    if (flags & THR_SUSPENDED) my_flags |= SUSPNDED;
    result = thr_create(stack, stack_size, start_routine,
   		        arg, flags & ~THR_DETACHED, &my_new_thread);
    if (result == 0) {
        t = GC_new_thread(my_new_thread);
        t -> flags = my_flags;
        if (!(my_flags & DETACHED)) cond_init(&(t -> join_cv), USYNC_THREAD, 0);
        t -> stack = stack;
        t -> stack_size = stack_size;
        if (new_thread != 0) *new_thread = my_new_thread;
        cond_signal(&GC_create_cv);
    } else {
	GC_multithreaded--;
        if (!(my_flags & CLIENT_OWNS_STACK)) {
      	    GC_stack_free(stack, stack_size);
	}
    }        
    UNLOCK();  
    return(result);
}

# else /* !GC_SOLARIS_THREADS */

#ifndef LINT
  int GC_no_sunOS_threads;
#endif
#endif