--- /dev/null
+/*
+ * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
+ * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
+ * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
+ * Copyright (c) 2000-2009 by Hewlett-Packard Development Company.
+ * All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose, provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+
+#include "private/pthread_support.h"
+
+#if defined(GC_PTHREADS) && !defined(GC_WIN32_THREADS) && \
+ !defined(GC_DARWIN_THREADS)
+
+#ifdef NACL
+
+#include <unistd.h>
+#include <sys/time.h>
+
+STATIC int GC_nacl_num_gc_threads = 0;
+STATIC __thread int GC_nacl_thread_idx = -1;
+STATIC int GC_nacl_park_threads_now = 0;
+STATIC pthread_t GC_nacl_thread_parker = -1;
+
+GC_INNER __thread GC_thread GC_nacl_gc_thread_self = NULL;
+
+int GC_nacl_thread_parked[MAX_NACL_GC_THREADS];
+int GC_nacl_thread_used[MAX_NACL_GC_THREADS];
+
+#elif !defined(GC_OPENBSD_THREADS)
+
+#include <signal.h>
+#include <semaphore.h>
+#include <errno.h>
+#include <unistd.h>
+#include "atomic_ops.h"
+
+/* It's safe to call original pthread_sigmask() here. */
+#undef pthread_sigmask
+
+#ifdef DEBUG_THREADS
+# ifndef NSIG
+# if defined(MAXSIG)
+# define NSIG (MAXSIG+1)
+# elif defined(_NSIG)
+# define NSIG _NSIG
+# elif defined(__SIGRTMAX)
+# define NSIG (__SIGRTMAX+1)
+# else
+ --> please fix it
+# endif
+# endif /* NSIG */
+
+ void GC_print_sig_mask(void)
+ {
+ sigset_t blocked;
+ int i;
+
+ if (pthread_sigmask(SIG_BLOCK, NULL, &blocked) != 0)
+ ABORT("pthread_sigmask failed");
+ GC_printf("Blocked: ");
+ for (i = 1; i < NSIG; i++) {
+ if (sigismember(&blocked, i))
+ GC_printf("%d ", i);
+ }
+ GC_printf("\n");
+ }
+#endif /* DEBUG_THREADS */
+
+/* Remove the signals that we want to allow in thread stopping */
+/* handler from a set. */
+STATIC void GC_remove_allowed_signals(sigset_t *set)
+{
+ if (sigdelset(set, SIGINT) != 0
+ || sigdelset(set, SIGQUIT) != 0
+ || sigdelset(set, SIGABRT) != 0
+ || sigdelset(set, SIGTERM) != 0) {
+ ABORT("sigdelset() failed");
+ }
+
+# ifdef MPROTECT_VDB
+ /* Handlers write to the thread structure, which is in the heap, */
+ /* and hence can trigger a protection fault. */
+ if (sigdelset(set, SIGSEGV) != 0
+# ifdef SIGBUS
+ || sigdelset(set, SIGBUS) != 0
+# endif
+ ) {
+ ABORT("sigdelset() failed");
+ }
+# endif
+}
+
+static sigset_t suspend_handler_mask;
+
+STATIC volatile AO_t GC_stop_count = 0;
+ /* Incremented at the beginning of GC_stop_world. */
+
+STATIC volatile AO_t GC_world_is_stopped = FALSE;
+ /* FALSE ==> it is safe for threads to restart, i.e. */
+ /* they will see another suspend signal before they */
+ /* are expected to stop (unless they have voluntarily */
+ /* stopped). */
+
+#ifdef GC_OSF1_THREADS
+ STATIC GC_bool GC_retry_signals = TRUE;
+#else
+ STATIC GC_bool GC_retry_signals = FALSE;
+#endif
+
+/*
+ * We use signals to stop threads during GC.
+ *
+ * Suspended threads wait in signal handler for SIG_THR_RESTART.
+ * That's more portable than semaphores or condition variables.
+ * (We do use sem_post from a signal handler, but that should be portable.)
+ *
+ * The thread suspension signal SIG_SUSPEND is now defined in gc_priv.h.
+ * Note that we can't just stop a thread; we need it to save its stack
+ * pointer(s) and acknowledge.
+ */
+
+#ifndef SIG_THR_RESTART
+# if defined(GC_HPUX_THREADS) || defined(GC_OSF1_THREADS) \
+ || defined(GC_NETBSD_THREADS)
+# ifdef _SIGRTMIN
+# define SIG_THR_RESTART _SIGRTMIN + 5
+# else
+# define SIG_THR_RESTART SIGRTMIN + 5
+# endif
+# else
+# define SIG_THR_RESTART SIGXCPU
+# endif
+#endif
+
+#ifdef GC_EXPLICIT_SIGNALS_UNBLOCK
+ /* Some targets (eg., Solaris) might require this to be called when */
+ /* doing thread registering from the thread destructor. */
+ GC_INNER void GC_unblock_gc_signals(void)
+ {
+ sigset_t set;
+ sigemptyset(&set);
+ sigaddset(&set, SIG_SUSPEND);
+ sigaddset(&set, SIG_THR_RESTART);
+ if (pthread_sigmask(SIG_UNBLOCK, &set, NULL) != 0)
+ ABORT("pthread_sigmask failed");
+ }
+#endif /* GC_EXPLICIT_SIGNALS_UNBLOCK */
+
+STATIC sem_t GC_suspend_ack_sem;
+
+#ifdef GC_NETBSD_THREADS
+# define GC_NETBSD_THREADS_WORKAROUND
+ /* It seems to be necessary to wait until threads have restarted. */
+ /* But it is unclear why that is the case. */
+ STATIC sem_t GC_restart_ack_sem;
+#endif
+
+STATIC void GC_suspend_handler_inner(ptr_t sig_arg, void *context);
+
+#ifdef SA_SIGINFO
+ /*ARGSUSED*/
+ STATIC void GC_suspend_handler(int sig, siginfo_t *info, void *context)
+#else
+ STATIC void GC_suspend_handler(int sig)
+#endif
+{
+# if defined(IA64) || defined(HP_PA) || defined(M68K)
+ int old_errno = errno;
+ GC_with_callee_saves_pushed(GC_suspend_handler_inner, (ptr_t)(word)sig);
+ errno = old_errno;
+# else
+ /* We believe that in all other cases the full context is already */
+ /* in the signal handler frame. */
+ int old_errno = errno;
+# ifndef SA_SIGINFO
+ void *context = 0;
+# endif
+ GC_suspend_handler_inner((ptr_t)(word)sig, context);
+ errno = old_errno;
+# endif
+}
+
+/*ARGSUSED*/
+STATIC void GC_suspend_handler_inner(ptr_t sig_arg, void *context)
+{
+ pthread_t self = pthread_self();
+ GC_thread me;
+ IF_CANCEL(int cancel_state;)
+ AO_t my_stop_count = AO_load(&GC_stop_count);
+
+ if ((signed_word)sig_arg != SIG_SUSPEND)
+ ABORT("Bad signal in suspend_handler");
+
+ DISABLE_CANCEL(cancel_state);
+ /* pthread_setcancelstate is not defined to be async-signal-safe. */
+ /* But the glibc version appears to be in the absence of */
+ /* asynchronous cancellation. And since this signal handler */
+ /* to block on sigsuspend, which is both async-signal-safe */
+ /* and a cancellation point, there seems to be no obvious way */
+ /* out of it. In fact, it looks to me like an async-signal-safe */
+ /* cancellation point is inherently a problem, unless there is */
+ /* some way to disable cancellation in the handler. */
+# ifdef DEBUG_THREADS
+ GC_log_printf("Suspending 0x%x\n", (unsigned)self);
+# endif
+
+ me = GC_lookup_thread(self);
+ /* The lookup here is safe, since I'm doing this on behalf */
+ /* of a thread which holds the allocation lock in order */
+ /* to stop the world. Thus concurrent modification of the */
+ /* data structure is impossible. */
+ if (me -> stop_info.last_stop_count == my_stop_count) {
+ /* Duplicate signal. OK if we are retrying. */
+ if (!GC_retry_signals) {
+ WARN("Duplicate suspend signal in thread %p\n", self);
+ }
+ RESTORE_CANCEL(cancel_state);
+ return;
+ }
+# ifdef SPARC
+ me -> stop_info.stack_ptr = GC_save_regs_in_stack();
+# else
+ me -> stop_info.stack_ptr = GC_approx_sp();
+# endif
+# ifdef IA64
+ me -> backing_store_ptr = GC_save_regs_in_stack();
+# endif
+
+ /* Tell the thread that wants to stop the world that this */
+ /* thread has been stopped. Note that sem_post() is */
+ /* the only async-signal-safe primitive in LinuxThreads. */
+ sem_post(&GC_suspend_ack_sem);
+ me -> stop_info.last_stop_count = my_stop_count;
+
+ /* Wait until that thread tells us to restart by sending */
+ /* this thread a SIG_THR_RESTART signal. */
+ /* SIG_THR_RESTART should be masked at this point. Thus */
+ /* there is no race. */
+ /* We do not continue until we receive a SIG_THR_RESTART, */
+ /* but we do not take that as authoritative. (We may be */
+ /* accidentally restarted by one of the user signals we */
+ /* don't block.) After we receive the signal, we use a */
+ /* primitive and expensive mechanism to wait until it's */
+ /* really safe to proceed. Under normal circumstances, */
+ /* this code should not be executed. */
+ do {
+ sigsuspend (&suspend_handler_mask);
+ } while (AO_load_acquire(&GC_world_is_stopped)
+ && AO_load(&GC_stop_count) == my_stop_count);
+ /* If the RESTART signal gets lost, we can still lose. That should */
+ /* be less likely than losing the SUSPEND signal, since we don't do */
+ /* much between the sem_post and sigsuspend. */
+ /* We'd need more handshaking to work around that. */
+ /* Simply dropping the sigsuspend call should be safe, but is */
+ /* unlikely to be efficient. */
+
+# ifdef DEBUG_THREADS
+ GC_log_printf("Continuing 0x%x\n", (unsigned)self);
+# endif
+ RESTORE_CANCEL(cancel_state);
+}
+
+STATIC void GC_restart_handler(int sig)
+{
+# if defined(DEBUG_THREADS) || defined(GC_NETBSD_THREADS_WORKAROUND)
+ int old_errno = errno; /* Preserve errno value. */
+# endif
+
+ if (sig != SIG_THR_RESTART) ABORT("Bad signal in suspend_handler");
+
+# ifdef GC_NETBSD_THREADS_WORKAROUND
+ sem_post(&GC_restart_ack_sem);
+# endif
+
+ /*
+ ** Note: even if we don't do anything useful here,
+ ** it would still be necessary to have a signal handler,
+ ** rather than ignoring the signals, otherwise
+ ** the signals will not be delivered at all, and
+ ** will thus not interrupt the sigsuspend() above.
+ */
+
+# ifdef DEBUG_THREADS
+ GC_log_printf("In GC_restart_handler for 0x%x\n",
+ (unsigned)pthread_self());
+# endif
+# if defined(DEBUG_THREADS) || defined(GC_NETBSD_THREADS_WORKAROUND)
+ errno = old_errno;
+# endif
+}
+
+#endif /* !GC_OPENBSD_THREADS && !NACL */
+
+#ifdef IA64
+# define IF_IA64(x) x
+#else
+# define IF_IA64(x)
+#endif
+/* We hold allocation lock. Should do exactly the right thing if the */
+/* world is stopped. Should not fail if it isn't. */
+GC_INNER void GC_push_all_stacks(void)
+{
+ GC_bool found_me = FALSE;
+ size_t nthreads = 0;
+ int i;
+ GC_thread p;
+ ptr_t lo, hi;
+ /* On IA64, we also need to scan the register backing store. */
+ IF_IA64(ptr_t bs_lo; ptr_t bs_hi;)
+ pthread_t self = pthread_self();
+ word total_size = 0;
+
+ if (!GC_thr_initialized) GC_thr_init();
+# ifdef DEBUG_THREADS
+ GC_log_printf("Pushing stacks from thread 0x%x\n", (unsigned)self);
+# endif
+ for (i = 0; i < THREAD_TABLE_SZ; i++) {
+ for (p = GC_threads[i]; p != 0; p = p -> next) {
+ if (p -> flags & FINISHED) continue;
+ ++nthreads;
+ if (THREAD_EQUAL(p -> id, self)) {
+ GC_ASSERT(!p->thread_blocked);
+# ifdef SPARC
+ lo = (ptr_t)GC_save_regs_in_stack();
+# else
+ lo = GC_approx_sp();
+# endif
+ found_me = TRUE;
+ IF_IA64(bs_hi = (ptr_t)GC_save_regs_in_stack();)
+ } else {
+ lo = p -> stop_info.stack_ptr;
+ IF_IA64(bs_hi = p -> backing_store_ptr;)
+ }
+ if ((p -> flags & MAIN_THREAD) == 0) {
+ hi = p -> stack_end;
+ IF_IA64(bs_lo = p -> backing_store_end);
+ } else {
+ /* The original stack. */
+ hi = GC_stackbottom;
+ IF_IA64(bs_lo = BACKING_STORE_BASE;)
+ }
+# ifdef DEBUG_THREADS
+ GC_log_printf("Stack for thread 0x%x = [%p,%p)\n",
+ (unsigned)(p -> id), lo, hi);
+# endif
+ if (0 == lo) ABORT("GC_push_all_stacks: sp not set!");
+ GC_push_all_stack_sections(lo, hi, p -> traced_stack_sect);
+# ifdef STACK_GROWS_UP
+ total_size += lo - hi;
+# else
+ total_size += hi - lo; /* lo <= hi */
+# endif
+# ifdef NACL
+ /* Push reg_storage as roots, this will cover the reg context. */
+ GC_push_all_stack((ptr_t)p -> stop_info.reg_storage,
+ (ptr_t)(p -> stop_info.reg_storage + NACL_GC_REG_STORAGE_SIZE));
+ total_size += NACL_GC_REG_STORAGE_SIZE * sizeof(ptr_t);
+# endif
+# ifdef IA64
+# ifdef DEBUG_THREADS
+ GC_log_printf("Reg stack for thread 0x%x = [%p,%p)\n",
+ (unsigned)p -> id, bs_lo, bs_hi);
+# endif
+ /* FIXME: This (if p->id==self) may add an unbounded number of */
+ /* entries, and hence overflow the mark stack, which is bad. */
+ GC_push_all_register_sections(bs_lo, bs_hi,
+ THREAD_EQUAL(p -> id, self),
+ p -> traced_stack_sect);
+ total_size += bs_hi - bs_lo; /* bs_lo <= bs_hi */
+# endif
+ }
+ }
+ if (GC_print_stats == VERBOSE) {
+ GC_log_printf("Pushed %d thread stacks\n", (int)nthreads);
+ }
+ if (!found_me && !GC_in_thread_creation)
+ ABORT("Collecting from unknown thread");
+ GC_total_stacksize = total_size;
+}
+
+#ifdef DEBUG_THREADS
+ /* There seems to be a very rare thread stopping problem. To help us */
+ /* debug that, we save the ids of the stopping thread. */
+ pthread_t GC_stopping_thread;
+ int GC_stopping_pid = 0;
+#endif
+
+#ifdef PLATFORM_ANDROID
+ extern int tkill(pid_t tid, int sig); /* from sys/linux-unistd.h */
+
+ static int android_thread_kill(pid_t tid, int sig)
+ {
+ int ret;
+ int old_errno = errno;
+
+ ret = tkill(tid, sig);
+ if (ret < 0) {
+ ret = errno;
+ errno = old_errno;
+ }
+
+ return ret;
+ }
+#endif /* PLATFORM_ANDROID */
+
+/* We hold the allocation lock. Suspend all threads that might */
+/* still be running. Return the number of suspend signals that */
+/* were sent. */
+STATIC int GC_suspend_all(void)
+{
+ int n_live_threads = 0;
+ int i;
+
+# ifndef NACL
+ GC_thread p;
+# ifndef GC_OPENBSD_THREADS
+ int result;
+# endif
+ pthread_t self = pthread_self();
+
+# ifdef DEBUG_THREADS
+ GC_stopping_thread = self;
+ GC_stopping_pid = getpid();
+# endif
+ for (i = 0; i < THREAD_TABLE_SZ; i++) {
+ for (p = GC_threads[i]; p != 0; p = p -> next) {
+ if (!THREAD_EQUAL(p -> id, self)) {
+ if (p -> flags & FINISHED) continue;
+ if (p -> thread_blocked) /* Will wait */ continue;
+# ifndef GC_OPENBSD_THREADS
+ if (p -> stop_info.last_stop_count == GC_stop_count) continue;
+ n_live_threads++;
+# endif
+# ifdef DEBUG_THREADS
+ GC_log_printf("Sending suspend signal to 0x%x\n",
+ (unsigned)(p -> id));
+# endif
+
+# ifdef GC_OPENBSD_THREADS
+ {
+ stack_t stack;
+ if (pthread_suspend_np(p -> id) != 0)
+ ABORT("pthread_suspend_np failed");
+ if (pthread_stackseg_np(p->id, &stack))
+ ABORT("pthread_stackseg_np failed");
+ p -> stop_info.stack_ptr = (ptr_t)stack.ss_sp - stack.ss_size;
+ }
+# else
+# ifndef PLATFORM_ANDROID
+ result = pthread_kill(p -> id, SIG_SUSPEND);
+# else
+ result = android_thread_kill(p -> kernel_id, SIG_SUSPEND);
+# endif
+ switch(result) {
+ case ESRCH:
+ /* Not really there anymore. Possible? */
+ n_live_threads--;
+ break;
+ case 0:
+ break;
+ default:
+ ABORT("pthread_kill failed");
+ }
+# endif
+ }
+ }
+ }
+
+# else /* NACL */
+# ifndef NACL_PARK_WAIT_NANOSECONDS
+# define NACL_PARK_WAIT_NANOSECONDS (100 * 1000)
+# endif
+# ifdef DEBUG_THREADS
+ GC_log_printf("pthread_stop_world: num_threads %d\n",
+ GC_nacl_num_gc_threads - 1);
+# endif
+ GC_nacl_thread_parker = pthread_self();
+ GC_nacl_park_threads_now = 1;
+# ifdef DEBUG_THREADS
+ GC_stopping_thread = GC_nacl_thread_parker;
+ GC_stopping_pid = getpid();
+# endif
+
+ while (1) {
+ int num_threads_parked = 0;
+ struct timespec ts;
+ int num_used = 0;
+
+ /* Check the 'parked' flag for each thread the GC knows about. */
+ for (i = 0; i < MAX_NACL_GC_THREADS
+ && num_used < GC_nacl_num_gc_threads; i++) {
+ if (GC_nacl_thread_used[i] == 1) {
+ num_used++;
+ if (GC_nacl_thread_parked[i] == 1) {
+ num_threads_parked++;
+ }
+ }
+ }
+ /* -1 for the current thread. */
+ if (num_threads_parked >= GC_nacl_num_gc_threads - 1)
+ break;
+ ts.tv_sec = 0;
+ ts.tv_nsec = NACL_PARK_WAIT_NANOSECONDS;
+# ifdef DEBUG_THREADS
+ GC_log_printf("Sleep waiting for %d threads to park...\n",
+ GC_nacl_num_gc_threads - num_threads_parked - 1);
+# endif
+ /* This requires _POSIX_TIMERS feature. */
+ nanosleep(&ts, 0);
+ }
+# endif /* NACL */
+ return n_live_threads;
+}
+
+GC_INNER void GC_stop_world(void)
+{
+# if !defined(GC_OPENBSD_THREADS) && !defined(NACL)
+ int i;
+ int n_live_threads;
+ int code;
+# endif
+ GC_ASSERT(I_HOLD_LOCK());
+# ifdef DEBUG_THREADS
+ GC_log_printf("Stopping the world from 0x%x\n", (unsigned)pthread_self());
+# endif
+
+ /* Make sure all free list construction has stopped before we start. */
+ /* No new construction can start, since free list construction is */
+ /* required to acquire and release the GC lock before it starts, */
+ /* and we have the lock. */
+# ifdef PARALLEL_MARK
+ if (GC_parallel) {
+ GC_acquire_mark_lock();
+ GC_ASSERT(GC_fl_builder_count == 0);
+ /* We should have previously waited for it to become zero. */
+ }
+# endif /* PARALLEL_MARK */
+
+# if defined(GC_OPENBSD_THREADS) || defined(NACL)
+ (void)GC_suspend_all();
+# else
+ AO_store(&GC_stop_count, GC_stop_count+1);
+ /* Only concurrent reads are possible. */
+ AO_store_release(&GC_world_is_stopped, TRUE);
+ n_live_threads = GC_suspend_all();
+
+ if (GC_retry_signals) {
+ unsigned long wait_usecs = 0; /* Total wait since retry. */
+# define WAIT_UNIT 3000
+# define RETRY_INTERVAL 100000
+ for (;;) {
+ int ack_count;
+
+ sem_getvalue(&GC_suspend_ack_sem, &ack_count);
+ if (ack_count == n_live_threads) break;
+ if (wait_usecs > RETRY_INTERVAL) {
+ int newly_sent = GC_suspend_all();
+
+ if (GC_print_stats) {
+ GC_log_printf("Resent %d signals after timeout\n", newly_sent);
+ }
+ sem_getvalue(&GC_suspend_ack_sem, &ack_count);
+ if (newly_sent < n_live_threads - ack_count) {
+ WARN("Lost some threads during GC_stop_world?!\n",0);
+ n_live_threads = ack_count + newly_sent;
+ }
+ wait_usecs = 0;
+ }
+ usleep(WAIT_UNIT);
+ wait_usecs += WAIT_UNIT;
+ }
+ }
+
+ for (i = 0; i < n_live_threads; i++) {
+ retry:
+ if (0 != (code = sem_wait(&GC_suspend_ack_sem))) {
+ /* On Linux, sem_wait is documented to always return zero. */
+ /* But the documentation appears to be incorrect. */
+ if (errno == EINTR) {
+ /* Seems to happen with some versions of gdb. */
+ goto retry;
+ }
+ ABORT("sem_wait for handler failed");
+ }
+ }
+# endif
+
+# ifdef PARALLEL_MARK
+ if (GC_parallel)
+ GC_release_mark_lock();
+# endif
+# ifdef DEBUG_THREADS
+ GC_log_printf("World stopped from 0x%x\n", (unsigned)pthread_self());
+ GC_stopping_thread = 0;
+# endif
+}
+
+#ifdef NACL
+# if defined(__x86_64__)
+# define NACL_STORE_REGS() \
+ do { \
+ __asm__ __volatile__ ("push %rbx"); \
+ __asm__ __volatile__ ("push %rbp"); \
+ __asm__ __volatile__ ("push %r12"); \
+ __asm__ __volatile__ ("push %r13"); \
+ __asm__ __volatile__ ("push %r14"); \
+ __asm__ __volatile__ ("push %r15"); \
+ __asm__ __volatile__ ("mov %%esp, %0" \
+ : "=m" (GC_nacl_gc_thread_self->stop_info.stack_ptr)); \
+ BCOPY(GC_nacl_gc_thread_self->stop_info.stack_ptr, \
+ GC_nacl_gc_thread_self->stop_info.reg_storage, \
+ NACL_GC_REG_STORAGE_SIZE * sizeof(ptr_t)); \
+ __asm__ __volatile__ ("naclasp $48, %r15"); \
+ } while (0)
+# elif defined(__i386__)
+# define NACL_STORE_REGS() \
+ do { \
+ __asm__ __volatile__ ("push %ebx"); \
+ __asm__ __volatile__ ("push %ebp"); \
+ __asm__ __volatile__ ("push %esi"); \
+ __asm__ __volatile__ ("push %edi"); \
+ __asm__ __volatile__ ("mov %%esp, %0" \
+ : "=m" (GC_nacl_gc_thread_self->stop_info.stack_ptr)); \
+ BCOPY(GC_nacl_gc_thread_self->stop_info.stack_ptr, \
+ GC_nacl_gc_thread_self->stop_info.reg_storage, \
+ NACL_GC_REG_STORAGE_SIZE * sizeof(ptr_t));\
+ __asm__ __volatile__ ("add $16, %esp"); \
+ } while (0)
+# else
+# error FIXME for non-amd64/x86 NaCl
+# endif
+
+ GC_API_OSCALL void nacl_pre_syscall_hook(void)
+ {
+ if (GC_nacl_thread_idx != -1) {
+ NACL_STORE_REGS();
+ GC_nacl_gc_thread_self->stop_info.stack_ptr = GC_approx_sp();
+ GC_nacl_thread_parked[GC_nacl_thread_idx] = 1;
+ }
+ }
+
+ GC_API_OSCALL void __nacl_suspend_thread_if_needed(void)
+ {
+ if (GC_nacl_park_threads_now) {
+ pthread_t self = pthread_self();
+
+ /* Don't try to park the thread parker. */
+ if (GC_nacl_thread_parker == self)
+ return;
+
+ /* This can happen when a thread is created outside of the GC */
+ /* system (wthread mostly). */
+ if (GC_nacl_thread_idx < 0)
+ return;
+
+ /* If it was already 'parked', we're returning from a syscall, */
+ /* so don't bother storing registers again, the GC has a set. */
+ if (!GC_nacl_thread_parked[GC_nacl_thread_idx]) {
+ NACL_STORE_REGS();
+ GC_nacl_gc_thread_self->stop_info.stack_ptr = GC_approx_sp();
+ }
+ GC_nacl_thread_parked[GC_nacl_thread_idx] = 1;
+ while (GC_nacl_park_threads_now) {
+ /* Just spin. */
+ }
+ GC_nacl_thread_parked[GC_nacl_thread_idx] = 0;
+
+ /* Clear out the reg storage for next suspend. */
+ BZERO(GC_nacl_gc_thread_self->stop_info.reg_storage,
+ NACL_GC_REG_STORAGE_SIZE * sizeof(ptr_t));
+ }
+ }
+
+ GC_API_OSCALL void nacl_post_syscall_hook(void)
+ {
+ /* Calling __nacl_suspend_thread_if_needed right away should */
+ /* guarantee we don't mutate the GC set. */
+ __nacl_suspend_thread_if_needed();
+ if (GC_nacl_thread_idx != -1) {
+ GC_nacl_thread_parked[GC_nacl_thread_idx] = 0;
+ }
+ }
+
+ STATIC GC_bool GC_nacl_thread_parking_inited = FALSE;
+ STATIC pthread_mutex_t GC_nacl_thread_alloc_lock = PTHREAD_MUTEX_INITIALIZER;
+
+ GC_INNER void GC_nacl_initialize_gc_thread(void)
+ {
+ int i;
+ pthread_mutex_lock(&GC_nacl_thread_alloc_lock);
+ if (!GC_nacl_thread_parking_inited) {
+ BZERO(GC_nacl_thread_parked, sizeof(GC_nacl_thread_parked));
+ BZERO(GC_nacl_thread_used, sizeof(GC_nacl_thread_used));
+ GC_nacl_thread_parking_inited = TRUE;
+ }
+ GC_ASSERT(GC_nacl_num_gc_threads <= MAX_NACL_GC_THREADS);
+ for (i = 0; i < MAX_NACL_GC_THREADS; i++) {
+ if (GC_nacl_thread_used[i] == 0) {
+ GC_nacl_thread_used[i] = 1;
+ GC_nacl_thread_idx = i;
+ GC_nacl_num_gc_threads++;
+ break;
+ }
+ }
+ pthread_mutex_unlock(&GC_nacl_thread_alloc_lock);
+ }
+
+ GC_INNER void GC_nacl_shutdown_gc_thread(void)
+ {
+ pthread_mutex_lock(&GC_nacl_thread_alloc_lock);
+ GC_ASSERT(GC_nacl_thread_idx >= 0);
+ GC_ASSERT(GC_nacl_thread_idx < MAX_NACL_GC_THREADS);
+ GC_ASSERT(GC_nacl_thread_used[GC_nacl_thread_idx] != 0);
+ GC_nacl_thread_used[GC_nacl_thread_idx] = 0;
+ GC_nacl_thread_idx = -1;
+ GC_nacl_num_gc_threads--;
+ pthread_mutex_unlock(&GC_nacl_thread_alloc_lock);
+ }
+#endif /* NACL */
+
+/* Caller holds allocation lock, and has held it continuously since */
+/* the world stopped. */
+GC_INNER void GC_start_world(void)
+{
+# ifndef NACL
+ pthread_t self = pthread_self();
+ register int i;
+ register GC_thread p;
+# ifndef GC_OPENBSD_THREADS
+ register int n_live_threads = 0;
+ register int result;
+# endif
+# ifdef GC_NETBSD_THREADS_WORKAROUND
+ int code;
+# endif
+
+# ifdef DEBUG_THREADS
+ GC_log_printf("World starting\n");
+# endif
+
+# ifndef GC_OPENBSD_THREADS
+ AO_store(&GC_world_is_stopped, FALSE);
+# endif
+ for (i = 0; i < THREAD_TABLE_SZ; i++) {
+ for (p = GC_threads[i]; p != 0; p = p -> next) {
+ if (!THREAD_EQUAL(p -> id, self)) {
+ if (p -> flags & FINISHED) continue;
+ if (p -> thread_blocked) continue;
+# ifndef GC_OPENBSD_THREADS
+ n_live_threads++;
+# endif
+# ifdef DEBUG_THREADS
+ GC_log_printf("Sending restart signal to 0x%x\n",
+ (unsigned)(p -> id));
+# endif
+
+# ifdef GC_OPENBSD_THREADS
+ if (pthread_resume_np(p -> id) != 0)
+ ABORT("pthread_resume_np failed");
+# else
+# ifndef PLATFORM_ANDROID
+ result = pthread_kill(p -> id, SIG_THR_RESTART);
+# else
+ result = android_thread_kill(p -> kernel_id, SIG_THR_RESTART);
+# endif
+ switch(result) {
+ case ESRCH:
+ /* Not really there anymore. Possible? */
+ n_live_threads--;
+ break;
+ case 0:
+ break;
+ default:
+ ABORT("pthread_kill failed");
+ }
+# endif
+ }
+ }
+ }
+# ifdef GC_NETBSD_THREADS_WORKAROUND
+ for (i = 0; i < n_live_threads; i++) {
+ while (0 != (code = sem_wait(&GC_restart_ack_sem))) {
+ if (errno != EINTR) {
+ if (GC_print_stats)
+ GC_log_printf("sem_wait() returned %d\n", code);
+ ABORT("sem_wait() for restart handler failed");
+ }
+ }
+ }
+# endif
+# ifdef DEBUG_THREADS
+ GC_log_printf("World started\n");
+# endif
+# else /* NACL */
+# ifdef DEBUG_THREADS
+ GC_log_printf("World starting...\n");
+# endif
+ GC_nacl_park_threads_now = 0;
+# endif
+}
+
+GC_INNER void GC_stop_init(void)
+{
+# if !defined(GC_OPENBSD_THREADS) && !defined(NACL)
+ struct sigaction act;
+
+ if (sem_init(&GC_suspend_ack_sem, GC_SEM_INIT_PSHARED, 0) != 0)
+ ABORT("sem_init failed");
+# ifdef GC_NETBSD_THREADS_WORKAROUND
+ if (sem_init(&GC_restart_ack_sem, GC_SEM_INIT_PSHARED, 0) != 0)
+ ABORT("sem_init failed");
+# endif
+
+# ifdef SA_RESTART
+ act.sa_flags = SA_RESTART
+# else
+ act.sa_flags = 0
+# endif
+# ifdef SA_SIGINFO
+ | SA_SIGINFO
+# endif
+ ;
+ if (sigfillset(&act.sa_mask) != 0) {
+ ABORT("sigfillset() failed");
+ }
+# ifdef GC_RTEMS_PTHREADS
+ if(sigprocmask(SIG_UNBLOCK, &act.sa_mask, NULL) != 0) {
+ ABORT("rtems sigprocmask() failed");
+ }
+# endif
+ GC_remove_allowed_signals(&act.sa_mask);
+ /* SIG_THR_RESTART is set in the resulting mask. */
+ /* It is unmasked by the handler when necessary. */
+# ifdef SA_SIGINFO
+ act.sa_sigaction = GC_suspend_handler;
+# else
+ act.sa_handler = GC_suspend_handler;
+# endif
+ if (sigaction(SIG_SUSPEND, &act, NULL) != 0) {
+ ABORT("Cannot set SIG_SUSPEND handler");
+ }
+
+# ifdef SA_SIGINFO
+ act.sa_flags &= ~ SA_SIGINFO;
+# endif
+ act.sa_handler = GC_restart_handler;
+ if (sigaction(SIG_THR_RESTART, &act, NULL) != 0) {
+ ABORT("Cannot set SIG_THR_RESTART handler");
+ }
+
+ /* Initialize suspend_handler_mask. It excludes SIG_THR_RESTART. */
+ if (sigfillset(&suspend_handler_mask) != 0) ABORT("sigfillset() failed");
+ GC_remove_allowed_signals(&suspend_handler_mask);
+ if (sigdelset(&suspend_handler_mask, SIG_THR_RESTART) != 0)
+ ABORT("sigdelset() failed");
+
+ /* Check for GC_RETRY_SIGNALS. */
+ if (0 != GETENV("GC_RETRY_SIGNALS")) {
+ GC_retry_signals = TRUE;
+ }
+ if (0 != GETENV("GC_NO_RETRY_SIGNALS")) {
+ GC_retry_signals = FALSE;
+ }
+ if (GC_print_stats && GC_retry_signals) {
+ GC_log_printf("Will retry suspend signal if necessary\n");
+ }
+# endif /* !GC_OPENBSD_THREADS && !NACL */
+}
+
+#endif
projects / hs-boehmgc.git / blobdiff