1 // Fault handler information. MacOSX version.
2 // Copyright (C) 1993-1999, 2002-2003 Bruno Haible <clisp.org at bruno>
4 // Copyright (C) 2003 Paolo Bonzini <gnu.org at bonzini>
6 // Used under BSD license with permission from Paolo Bonzini and Bruno Haible,
9 // http://sourceforge.net/mailarchive/message.php?msg_name=200503102200.32002.bruno%40clisp.org
11 // Modified for Factor by Slava Pestov
17 // The exception port on which our thread listens.
18 mach_port_t our_exception_port;
20 // The following sources were used as a *reference* for this exception handling
23 // 1. Apple's mach/xnu documentation
24 // 2. Timothy J. Wood's "Mach Exception Handlers 101" post to the
25 // omnigroup's macosx-dev list.
26 // http://www.wodeveloper.com/omniLists/macosx-dev/2000/June/msg00137.html
28 // Modify a suspended thread's thread_state so that when the thread resumes
29 // executing, the call frame of the current C primitive (if any) is rewound, and
30 // the appropriate Factor error is thrown from the top-most Factor frame.
31 void factor_vm::call_fault_handler(exception_type_t exception,
32 exception_data_type_t code,
33 MACH_EXC_STATE_TYPE* exc_state,
34 MACH_THREAD_STATE_TYPE* thread_state,
35 MACH_FLOAT_STATE_TYPE* float_state) {
38 if (exception == EXC_BAD_ACCESS) {
39 set_memory_protection_error(MACH_EXC_STATE_FAULT(exc_state),
40 (cell)MACH_PROGRAM_COUNTER(thread_state));
41 handler = (cell)factor::memory_signal_handler_impl;
42 } else if (exception == EXC_ARITHMETIC && code != MACH_EXC_INTEGER_DIV) {
43 signal_fpu_status = fpu_status(mach_fpu_status(float_state));
44 mach_clear_fpu_status(float_state);
45 handler = (cell)factor::fp_signal_handler_impl;
49 signal_number = SIGFPE;
51 case EXC_BAD_INSTRUCTION:
52 signal_number = SIGILL;
55 signal_number = SIGABRT;
59 handler = (cell)factor::synchronous_signal_handler_impl;
62 FACTOR_ASSERT(handler != 0);
64 dispatch_signal_handler((cell*)&MACH_STACK_POINTER(thread_state),
65 (cell*)&MACH_PROGRAM_COUNTER(thread_state),
69 static void call_fault_handler(mach_port_t thread, exception_type_t exception,
70 exception_data_type_t code,
71 MACH_EXC_STATE_TYPE* exc_state,
72 MACH_THREAD_STATE_TYPE* thread_state,
73 MACH_FLOAT_STATE_TYPE* float_state) {
74 // Look up the VM instance involved
75 THREADHANDLE thread_id = pthread_from_mach_thread_np(thread);
76 FACTOR_ASSERT(thread_id);
77 std::map<THREADHANDLE, factor_vm*>::const_iterator vm =
78 thread_vms.find(thread_id);
80 // Handle the exception
81 if (vm != thread_vms.end())
82 vm->second->call_fault_handler(exception, code, exc_state, thread_state,
86 // Handle an exception by invoking the user's fault handler and/or forwarding
87 // the duty to the previously installed handlers.
88 extern "C" kern_return_t catch_exception_raise(
89 mach_port_t exception_port, mach_port_t thread, mach_port_t task,
90 exception_type_t exception, exception_data_t code,
91 mach_msg_type_number_t code_count) {
92 // 10.6 likes to report exceptions from child processes too. Ignore those
93 if (task != mach_task_self())
96 // Get fault information and the faulting thread's register contents..
97 // See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_get_state.html.
98 MACH_EXC_STATE_TYPE exc_state;
99 mach_msg_type_number_t exc_state_count = MACH_EXC_STATE_COUNT;
100 if (thread_get_state(thread, MACH_EXC_STATE_FLAVOR, (natural_t*)&exc_state,
103 // The thread is supposed to be suspended while the exception
104 // handler is called. This shouldn't fail.
108 MACH_THREAD_STATE_TYPE thread_state;
109 mach_msg_type_number_t thread_state_count = MACH_THREAD_STATE_COUNT;
110 if (thread_get_state(thread, MACH_THREAD_STATE_FLAVOR,
111 (natural_t*)&thread_state, &thread_state_count) !=
113 // The thread is supposed to be suspended while the exception
114 // handler is called. This shouldn't fail.
118 MACH_FLOAT_STATE_TYPE float_state;
119 mach_msg_type_number_t float_state_count = MACH_FLOAT_STATE_COUNT;
120 if (thread_get_state(thread, MACH_FLOAT_STATE_FLAVOR,
121 (natural_t*)&float_state, &float_state_count) !=
123 // The thread is supposed to be suspended while the exception
124 // handler is called. This shouldn't fail.
128 // Modify registers so to have the thread resume executing the
130 call_fault_handler(thread, exception, code[0], &exc_state, &thread_state,
133 // Set the faulting thread's register contents..
134 // See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_set_state.html.
135 if (thread_set_state(thread, MACH_FLOAT_STATE_FLAVOR,
136 (natural_t*)&float_state, float_state_count) !=
141 if (thread_set_state(thread, MACH_THREAD_STATE_FLAVOR,
142 (natural_t*)&thread_state, thread_state_count) !=
150 // The main function of the thread listening for exceptions.
151 static void* mach_exception_thread(void* arg) {
153 // These two structures contain some private kernel data. We don't need
154 // to access any of it so we don't bother defining a proper struct. The
155 // correct definitions are in the xnu source code.
156 // Buffer for a message to be received.
158 mach_msg_header_t head;
159 mach_msg_body_t msgh_body;
162 // Buffer for a reply message.
164 mach_msg_header_t head;
168 // Wait for a message on the exception port.
169 if (mach_msg(&msg.head, MACH_RCV_MSG | MACH_RCV_LARGE, 0, sizeof(msg),
170 our_exception_port, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL) !=
175 // Handle the message: Call exc_server, which will call
176 // catch_exception_raise and produce a reply message.
177 exc_server(&msg.head, &reply.head);
180 if (mach_msg(&reply.head, MACH_SEND_MSG, reply.head.msgh_size, 0,
181 MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL) !=
186 return NULL; // quiet warning
189 // Initialize the Mach exception handler thread.
190 void mach_initialize() {
192 exception_mask_t mask;
194 self = mach_task_self();
196 // Allocate a port on which the thread shall listen for exceptions.
197 if (mach_port_allocate(self, MACH_PORT_RIGHT_RECEIVE, &our_exception_port) !=
199 fatal_error("mach_port_allocate() failed", 0);
202 // http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/mach_port_insert_right.html.
204 if (mach_port_insert_right(self, our_exception_port, our_exception_port,
205 MACH_MSG_TYPE_MAKE_SEND) !=
207 fatal_error("mach_port_insert_right() failed", 0);
209 // The exceptions we want to catch.
210 mask = EXC_MASK_BAD_ACCESS | EXC_MASK_BAD_INSTRUCTION | EXC_MASK_ARITHMETIC;
212 // Create the thread listening on the exception port.
213 start_thread(mach_exception_thread, NULL);
215 // Replace the exception port info for these exceptions with our own.
216 // Note that we replace the exception port for the entire task, not only
217 // for a particular thread. This has the effect that when our exception
218 // port gets the message, the thread specific exception port has already
219 // been asked, and we don't need to bother about it. See
220 // http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html.
221 if (task_set_exception_ports(self, mask, our_exception_port,
222 EXCEPTION_DEFAULT, MACHINE_THREAD_STATE) !=
224 fatal_error("task_set_exception_ports() failed", 0);