2 * sgen-os-posix.c: Posix support.
5 * Paolo Molaro (lupus@ximian.com)
6 * Mark Probst (mprobst@novell.com)
7 * Geoff Norton (gnorton@novell.com)
9 * Copyright 2010 Novell, Inc (http://www.novell.com)
10 * Copyright (C) 2012 Xamarin Inc
12 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
17 #if defined(HAVE_SGEN_GC) && !defined(USE_COOP_GC)
18 #if !defined(__MACH__) && !MONO_MACH_ARCH_SUPPORTED && defined(HAVE_PTHREAD_KILL)
22 #include "sgen/sgen-gc.h"
23 #include "metadata/gc-internals.h"
24 #include "sgen/sgen-archdep.h"
25 #include "metadata/object-internals.h"
26 #include "utils/mono-signal-handler.h"
28 #if defined(__APPLE__) || defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
29 const static int suspend_signal_num = SIGXFSZ;
31 const static int suspend_signal_num = SIGPWR;
33 const static int restart_signal_num = SIGXCPU;
35 static SgenSemaphore suspend_ack_semaphore;
36 static SgenSemaphore *suspend_ack_semaphore_ptr;
38 static sigset_t suspend_signal_mask;
39 static sigset_t suspend_ack_signal_mask;
42 suspend_thread (SgenThreadInfo *info, void *context)
48 info->client_info.stopped_domain = mono_domain_get ();
49 info->client_info.signal = 0;
50 stop_count = sgen_global_stop_count;
51 /* duplicate signal */
52 if (0 && info->client_info.stop_count == stop_count)
56 mono_sigctx_to_monoctx (context, &ctx);
57 info->client_info.stopped_ip = MONO_CONTEXT_GET_IP (&ctx);
58 stack_start = (((guint8 *) MONO_CONTEXT_GET_SP (&ctx)) - REDZONE_SIZE);
60 info->client_info.stopped_ip = NULL;
64 /* If stack_start is not within the limits, then don't set it
65 in info and we will be restarted. */
66 if (stack_start >= info->client_info.stack_start_limit && stack_start <= info->client_info.stack_end) {
67 info->client_info.stack_start = stack_start;
70 memcpy (&info->client_info.ctx, &ctx, sizeof (MonoContext));
72 memset (&info->client_info.ctx, 0, sizeof (MonoContext));
75 g_assert (!info->client_info.stack_start);
79 if (mono_gc_get_gc_callbacks ()->thread_suspend_func)
80 mono_gc_get_gc_callbacks ()->thread_suspend_func (info->client_info.runtime_data, context, NULL);
82 SGEN_LOG (4, "Posting suspend_ack_semaphore for suspend from %p %p", info, (gpointer) (gsize) mono_native_thread_id_get ());
85 Block the restart signal.
86 We need to block the restart signal while posting to the suspend_ack semaphore or we race to sigsuspend,
87 which might miss the signal and get stuck.
89 pthread_sigmask (SIG_BLOCK, &suspend_ack_signal_mask, NULL);
91 /* notify the waiting thread */
92 SGEN_SEMAPHORE_POST (suspend_ack_semaphore_ptr);
93 info->client_info.stop_count = stop_count;
95 /* wait until we receive the restart signal */
97 info->client_info.signal = 0;
98 sigsuspend (&suspend_signal_mask);
99 } while (info->client_info.signal != restart_signal_num);
101 /* Unblock the restart signal. */
102 pthread_sigmask (SIG_UNBLOCK, &suspend_ack_signal_mask, NULL);
104 SGEN_LOG (4, "Posting suspend_ack_semaphore for resume from %p %p\n", info, (gpointer) (gsize) mono_native_thread_id_get ());
105 /* notify the waiting thread */
106 SGEN_SEMAPHORE_POST (suspend_ack_semaphore_ptr);
109 /* LOCKING: assumes the GC lock is held (by the stopping thread) */
110 MONO_SIG_HANDLER_FUNC (static, suspend_handler)
113 * The suspend signal handler potentially uses syscalls that
114 * can set errno, and it calls functions that use the hazard
115 * pointer machinery. Since we're interrupting other code we
116 * must restore those to the values they had when we
119 SgenThreadInfo *info;
120 int old_errno = errno;
121 int hp_save_index = mono_hazard_pointer_save_for_signal_handler ();
122 MONO_SIG_HANDLER_GET_CONTEXT;
124 info = mono_thread_info_current ();
125 suspend_thread (info, ctx);
127 mono_hazard_pointer_restore_for_signal_handler (hp_save_index);
131 MONO_SIG_HANDLER_FUNC (static, restart_handler)
133 SgenThreadInfo *info;
134 int old_errno = errno;
136 info = mono_thread_info_current ();
137 info->client_info.signal = restart_signal_num;
138 SGEN_LOG (4, "Restart handler in %p %p", info, (gpointer) (gsize) mono_native_thread_id_get ());
143 sgen_resume_thread (SgenThreadInfo *info)
145 return mono_threads_pthread_kill (info, restart_signal_num) == 0;
149 sgen_suspend_thread (SgenThreadInfo *info)
151 return mono_threads_pthread_kill (info, suspend_signal_num) == 0;
155 sgen_wait_for_suspend_ack (int count)
159 for (i = 0; i < count; ++i) {
160 while ((result = SGEN_SEMAPHORE_WAIT (suspend_ack_semaphore_ptr)) != 0) {
161 if (errno != EINTR) {
162 g_error ("SGEN_SEMAPHORE_WAIT FAILED with %d errno %d (%s)", result, errno, strerror (errno));
169 sgen_thread_handshake (BOOL suspend)
172 int signum = suspend ? suspend_signal_num : restart_signal_num;
174 MonoNativeThreadId me = mono_native_thread_id_get ();
177 mono_thread_info_current ()->client_info.suspend_done = TRUE;
178 FOREACH_THREAD (info) {
179 if (mono_native_thread_id_equals (mono_thread_info_get_tid (info), me)) {
182 info->client_info.suspend_done = FALSE;
183 if (info->client_info.gc_disabled)
185 /*if (signum == suspend_signal_num && info->stop_count == global_stop_count)
187 result = mono_threads_pthread_kill (info, signum);
191 info->client_info.skip = 1;
195 sgen_wait_for_suspend_ack (count);
197 SGEN_LOG (4, "%s handshake for %d threads\n", suspend ? "suspend" : "resume", count);
205 struct sigaction sinfo;
207 if (mono_thread_info_unified_management_enabled ())
210 suspend_ack_semaphore_ptr = &suspend_ack_semaphore;
211 SGEN_SEMAPHORE_INIT (&suspend_ack_semaphore, 0);
213 sigfillset (&sinfo.sa_mask);
214 sinfo.sa_flags = SA_RESTART | SA_SIGINFO;
215 sinfo.sa_sigaction = suspend_handler;
216 if (sigaction (suspend_signal_num, &sinfo, NULL) != 0) {
217 g_error ("failed sigaction");
220 sinfo.sa_handler = (void (*)(int))restart_handler;
221 if (sigaction (restart_signal_num, &sinfo, NULL) != 0) {
222 g_error ("failed sigaction");
225 sigfillset (&suspend_signal_mask);
226 sigdelset (&suspend_signal_mask, restart_signal_num);
228 sigemptyset (&suspend_ack_signal_mask);
229 sigaddset (&suspend_ack_signal_mask, restart_signal_num);
234 mono_gc_get_suspend_signal (void)
236 return suspend_signal_num;
240 mono_gc_get_restart_signal (void)
242 return restart_signal_num;