/*
* Called when a thread receives an async exception while executing unmanaged code.
* Instead of checking for this exception in the managed-to-native wrapper, we hijack
* the return address on the stack to point to a helper routine which throws the
* exception.
*/
void
mono_arch_notify_pending_exc (MonoThreadInfo *info)
{
MonoLMF *lmf = mono_get_lmf ();
if (!info) {
lmf = mono_get_lmf ();
} else {
g_assert (mono_thread_info_get_suspend_state (info)->valid);
lmf = mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_LMF];
}
if (!lmf)
/* Not yet started */
return;
if (lmf->rsp == 0)
/* Initial LMF */
return;
if ((guint64)lmf->previous_lmf & 5)
/* Already hijacked or trampoline LMF entry */
return;
/* lmf->rsp is set just before making the call which transitions to unmanaged code */
lmf->rip = *(guint64*)(lmf->rsp - 8);
/* Signal that lmf->rip is set */
lmf->previous_lmf = (gpointer)((guint64)lmf->previous_lmf | 1);
*(gpointer*)(lmf->rsp - 8) = throw_pending_exception;
}
/*
FIXME fix cardtable WB to be out of line and check with the runtime if the target is not the
WB trampoline. Another option is to encode wb ranges in MonoJitInfo, but that is somewhat hard.
*/
static gboolean
is_thread_in_critical_region (MonoThreadInfo *info)
{
MonoMethod *method;
MonoJitInfo *ji;
gpointer stack_start;
MonoThreadUnwindState *state;
if (mono_threads_platform_in_critical_region (mono_thread_info_get_tid (info)))
return TRUE;
/* Are we inside a system critical region? */
if (info->inside_critical_region)
return TRUE;
/* Are we inside a GC critical region? */
if (threads_callbacks.mono_thread_in_critical_region && threads_callbacks.mono_thread_in_critical_region (info)) {
return TRUE;
}
/* The target thread might be shutting down and the domain might be null, which means no managed code left to run. */
state = mono_thread_info_get_suspend_state (info);
if (!state->unwind_data [MONO_UNWIND_DATA_DOMAIN])
return FALSE;
stack_start = MONO_CONTEXT_GET_SP (&state->ctx);
/* altstack signal handler, sgen can't handle them, so we treat them as critical */
if (stack_start < info->stack_start_limit || stack_start >= info->stack_end)
return TRUE;
if (threads_callbacks.ip_in_critical_region)
return threads_callbacks.ip_in_critical_region ((MonoDomain *) state->unwind_data [MONO_UNWIND_DATA_DOMAIN], (char *) MONO_CONTEXT_GET_IP (&state->ctx));
ji = mono_jit_info_table_find (
(MonoDomain *) state->unwind_data [MONO_UNWIND_DATA_DOMAIN],
(char *) MONO_CONTEXT_GET_IP (&state->ctx));
if (!ji)
return FALSE;
method = mono_jit_info_get_method (ji);
return threads_callbacks.mono_method_is_critical (method);
}
static void
sgen_unified_suspend_stop_world (void)
{
int restart_counter;
int sleep_duration = -1;
mono_threads_begin_global_suspend ();
THREADS_STW_DEBUG ("[GC-STW-BEGIN] *** BEGIN SUSPEND *** \n");
FOREACH_THREAD (info) {
int reason;
info->client_info.skip = FALSE;
info->client_info.suspend_done = FALSE;
if (sgen_is_thread_in_current_stw (info, &reason)) {
info->client_info.skip = !mono_thread_info_begin_suspend (info);
THREADS_STW_DEBUG ("[GC-STW-BEGIN-SUSPEND] SUSPEND thread %p skip %d\n", mono_thread_info_get_tid (info), info->client_info.skip);
} else {
THREADS_STW_DEBUG ("[GC-STW-BEGIN-SUSPEND] IGNORE thread %p skip %d reason %d\n", mono_thread_info_get_tid (info), info->client_info.skip, reason);
}
} FOREACH_THREAD_END
mono_thread_info_current ()->client_info.suspend_done = TRUE;
mono_threads_wait_pending_operations ();
for (;;) {
restart_counter = 0;
FOREACH_THREAD (info) {
int reason = 0;
if (info->client_info.suspend_done || !sgen_is_thread_in_current_stw (info, &reason)) {
THREADS_STW_DEBUG ("[GC-STW-RESTART] IGNORE RESUME thread %p not been processed done %d current %d reason %d\n", mono_thread_info_get_tid (info), info->client_info.suspend_done, !sgen_is_thread_in_current_stw (info, NULL), reason);
continue;
}
/*
All threads that reach here are pristine suspended. This means the following:
- We haven't accepted the previous suspend as good.
- We haven't gave up on it for this STW (it's either bad or asked not to)
*/
if (mono_thread_info_in_critical_location (info)) {
gboolean res;
gint suspend_count = mono_thread_info_suspend_count (info);
if (!(suspend_count == 1))
g_error ("[%p] suspend_count = %d, but should be 1", mono_thread_info_get_tid (info), suspend_count);
res = mono_thread_info_begin_resume (info);
THREADS_STW_DEBUG ("[GC-STW-RESTART] RESTART thread %p skip %d\n", mono_thread_info_get_tid (info), res);
if (res)
++restart_counter;
else
info->client_info.skip = TRUE;
} else {
THREADS_STW_DEBUG ("[GC-STW-RESTART] DONE thread %p deemed fully suspended\n", mono_thread_info_get_tid (info));
g_assert (!info->client_info.in_critical_region);
info->client_info.suspend_done = TRUE;
}
} FOREACH_THREAD_END
if (restart_counter == 0)
break;
mono_threads_wait_pending_operations ();
if (sleep_duration < 0) {
mono_thread_info_yield ();
sleep_duration = 0;
} else {
g_usleep (sleep_duration);
sleep_duration += 10;
}
FOREACH_THREAD (info) {
int reason = 0;
if (info->client_info.suspend_done || !sgen_is_thread_in_current_stw (info, &reason)) {
THREADS_STW_DEBUG ("[GC-STW-RESTART] IGNORE SUSPEND thread %p not been processed done %d current %d reason %d\n", mono_thread_info_get_tid (info), info->client_info.suspend_done, !sgen_is_thread_in_current_stw (info, NULL), reason);
continue;
}
if (mono_thread_info_is_running (info)) {
gboolean res = mono_thread_info_begin_suspend (info);
THREADS_STW_DEBUG ("[GC-STW-RESTART] SUSPEND thread %p skip %d\n", mono_thread_info_get_tid (info), res);
if (!res)
info->client_info.skip = TRUE;
}
} FOREACH_THREAD_END
mono_threads_wait_pending_operations ();
}
FOREACH_THREAD (info) {
int reason = 0;
if (sgen_is_thread_in_current_stw (info, &reason)) {
MonoThreadUnwindState *state;
THREADS_STW_DEBUG ("[GC-STW-SUSPEND-END] thread %p is suspended\n", mono_thread_info_get_tid (info));
g_assert (info->client_info.suspend_done);
state = mono_thread_info_get_suspend_state (info);
info->client_info.ctx = state->ctx;
if (!state->unwind_data [MONO_UNWIND_DATA_DOMAIN] || !state->unwind_data [MONO_UNWIND_DATA_LMF]) {
/* thread is starting or detaching, nothing to scan here */
info->client_info.stopped_domain = NULL;
info->client_info.stopped_ip = NULL;
info->client_info.stack_start = NULL;
} else {
/* Once we remove the old suspend code, we should move sgen to directly access the state in MonoThread */
info->client_info.stopped_domain = (MonoDomain*) mono_thread_info_tls_get (info, TLS_KEY_DOMAIN);
info->client_info.stopped_ip = (gpointer) (MONO_CONTEXT_GET_IP (&info->client_info.ctx));
info->client_info.stack_start = (gpointer) ((char*)MONO_CONTEXT_GET_SP (&info->client_info.ctx) - REDZONE_SIZE);
/* altstack signal handler, sgen can't handle them, mono-threads should have handled this. */
if (!info->client_info.stack_start
|| info->client_info.stack_start < info->client_info.stack_start_limit
|| info->client_info.stack_start >= info->client_info.stack_end) {
g_error ("BAD STACK: stack_start = %p, stack_start_limit = %p, stack_end = %p",
info->client_info.stack_start, info->client_info.stack_start_limit, info->client_info.stack_end);
}
}
binary_protocol_thread_suspend ((gpointer) mono_thread_info_get_tid (info), info->client_info.stopped_ip);
} else {
THREADS_STW_DEBUG ("[GC-STW-SUSPEND-END] thread %p is NOT suspended, reason %d\n", mono_thread_info_get_tid (info), reason);
g_assert (!info->client_info.suspend_done || info == mono_thread_info_current ());
}
} FOREACH_THREAD_END
}
static void
sgen_unified_suspend_stop_world (void)
{
int sleep_duration = -1;
mono_threads_begin_global_suspend ();
THREADS_STW_DEBUG ("[GC-STW-BEGIN][%p] *** BEGIN SUSPEND *** \n", mono_thread_info_get_tid (mono_thread_info_current ()));
FOREACH_THREAD (info) {
info->client_info.skip = FALSE;
info->client_info.suspend_done = FALSE;
int reason;
if (!sgen_is_thread_in_current_stw (info, &reason)) {
THREADS_STW_DEBUG ("[GC-STW-BEGIN-SUSPEND] IGNORE thread %p skip %s reason %d\n", mono_thread_info_get_tid (info), info->client_info.skip ? "true" : "false", reason);
continue;
}
info->client_info.skip = !mono_thread_info_begin_suspend (info);
THREADS_STW_DEBUG ("[GC-STW-BEGIN-SUSPEND] SUSPEND thread %p skip %s\n", mono_thread_info_get_tid (info), info->client_info.skip ? "true" : "false");
} FOREACH_THREAD_END
mono_thread_info_current ()->client_info.suspend_done = TRUE;
mono_threads_wait_pending_operations ();
for (;;) {
gint restart_counter = 0;
FOREACH_THREAD (info) {
gint suspend_count;
int reason = 0;
if (info->client_info.suspend_done || !sgen_is_thread_in_current_stw (info, &reason)) {
THREADS_STW_DEBUG ("[GC-STW-RESTART] IGNORE RESUME thread %p not been processed done %d current %d reason %d\n", mono_thread_info_get_tid (info), info->client_info.suspend_done, !sgen_is_thread_in_current_stw (info, NULL), reason);
continue;
}
/*
All threads that reach here are pristine suspended. This means the following:
- We haven't accepted the previous suspend as good.
- We haven't gave up on it for this STW (it's either bad or asked not to)
*/
if (!mono_thread_info_in_critical_location (info)) {
info->client_info.suspend_done = TRUE;
THREADS_STW_DEBUG ("[GC-STW-RESTART] DONE thread %p deemed fully suspended\n", mono_thread_info_get_tid (info));
continue;
}
suspend_count = mono_thread_info_suspend_count (info);
if (!(suspend_count == 1))
g_error ("[%p] suspend_count = %d, but should be 1", mono_thread_info_get_tid (info), suspend_count);
info->client_info.skip = !mono_thread_info_begin_resume (info);
if (!info->client_info.skip)
restart_counter += 1;
THREADS_STW_DEBUG ("[GC-STW-RESTART] RESTART thread %p skip %s\n", mono_thread_info_get_tid (info), info->client_info.skip ? "true" : "false");
} FOREACH_THREAD_END
mono_threads_wait_pending_operations ();
if (restart_counter == 0)
break;
if (sleep_duration < 0) {
mono_thread_info_yield ();
sleep_duration = 0;
} else {
g_usleep (sleep_duration);
sleep_duration += 10;
}
FOREACH_THREAD (info) {
int reason = 0;
if (info->client_info.suspend_done || !sgen_is_thread_in_current_stw (info, &reason)) {
THREADS_STW_DEBUG ("[GC-STW-RESTART] IGNORE SUSPEND thread %p not been processed done %d current %d reason %d\n", mono_thread_info_get_tid (info), info->client_info.suspend_done, !sgen_is_thread_in_current_stw (info, NULL), reason);
continue;
}
if (!mono_thread_info_is_running (info)) {
THREADS_STW_DEBUG ("[GC-STW-RESTART] IGNORE SUSPEND thread %p not running\n", mono_thread_info_get_tid (info));
continue;
}
info->client_info.skip = !mono_thread_info_begin_suspend (info);
THREADS_STW_DEBUG ("[GC-STW-RESTART] SUSPEND thread %p skip %s\n", mono_thread_info_get_tid (info), info->client_info.skip ? "true" : "false");
} FOREACH_THREAD_END
mono_threads_wait_pending_operations ();
}
FOREACH_THREAD (info) {
gpointer stopped_ip;
int reason = 0;
if (!sgen_is_thread_in_current_stw (info, &reason)) {
g_assert (!info->client_info.suspend_done || info == mono_thread_info_current ());
THREADS_STW_DEBUG ("[GC-STW-SUSPEND-END] thread %p is NOT suspended, reason %d\n", mono_thread_info_get_tid (info), reason);
continue;
}
g_assert (info->client_info.suspend_done);
info->client_info.ctx = mono_thread_info_get_suspend_state (info)->ctx;
/* Once we remove the old suspend code, we should move sgen to directly access the state in MonoThread */
info->client_info.stack_start = (gpointer) ((char*)MONO_CONTEXT_GET_SP (&info->client_info.ctx) - REDZONE_SIZE);
/* altstack signal handler, sgen can't handle them, mono-threads should have handled this. */
if (!info->client_info.stack_start
|| info->client_info.stack_start < info->client_info.stack_start_limit
|| info->client_info.stack_start >= info->client_info.stack_end) {
g_error ("BAD STACK: stack_start = %p, stack_start_limit = %p, stack_end = %p",
info->client_info.stack_start, info->client_info.stack_start_limit, info->client_info.stack_end);
}
stopped_ip = (gpointer) (MONO_CONTEXT_GET_IP (&info->client_info.ctx));
binary_protocol_thread_suspend ((gpointer) mono_thread_info_get_tid (info), stopped_ip);
THREADS_STW_DEBUG ("[GC-STW-SUSPEND-END] thread %p is suspended, stopped_ip = %p, stack = %p -> %p\n",
mono_thread_info_get_tid (info), stopped_ip, info->client_info.stack_start, info->client_info.stack_start ? info->client_info.stack_end : NULL);
} FOREACH_THREAD_END
}
