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 signal_fault_addr = MACH_EXC_STATE_FAULT(exc_state);
40 signal_fault_pc = (cell)MACH_PROGRAM_COUNTER(thread_state);
41 verify_memory_protection_error(signal_fault_addr);
42 handler = (cell)factor::memory_signal_handler_impl;
43 } else if (exception == EXC_ARITHMETIC && code != MACH_EXC_INTEGER_DIV) {
44 signal_fpu_status = fpu_status(mach_fpu_status(float_state));
45 mach_clear_fpu_status(float_state);
46 handler = (cell)factor::fp_signal_handler_impl;
50 signal_number = SIGFPE;
52 case EXC_BAD_INSTRUCTION:
53 signal_number = SIGILL;
56 signal_number = SIGABRT;
60 handler = (cell)factor::synchronous_signal_handler_impl;
63 FACTOR_ASSERT(handler != 0);
65 dispatch_signal_handler((cell*)&MACH_STACK_POINTER(thread_state),
66 (cell*)&MACH_PROGRAM_COUNTER(thread_state),
70 static void call_fault_handler(mach_port_t thread, exception_type_t exception,
71 exception_data_type_t code,
72 MACH_EXC_STATE_TYPE* exc_state,
73 MACH_THREAD_STATE_TYPE* thread_state,
74 MACH_FLOAT_STATE_TYPE* float_state) {
75 /* Look up the VM instance involved */
76 THREADHANDLE thread_id = pthread_from_mach_thread_np(thread);
77 FACTOR_ASSERT(thread_id);
78 std::map<THREADHANDLE, factor_vm*>::const_iterator vm =
79 thread_vms.find(thread_id);
81 /* Handle the exception */
82 if (vm != thread_vms.end())
83 vm->second->call_fault_handler(exception, code, exc_state, thread_state,
87 /* Handle an exception by invoking the user's fault handler and/or forwarding
88 the duty to the previously installed handlers. */
89 extern "C" kern_return_t catch_exception_raise(
90 mach_port_t exception_port, mach_port_t thread, mach_port_t task,
91 exception_type_t exception, exception_data_t code,
92 mach_msg_type_number_t code_count) {
93 /* 10.6 likes to report exceptions from child processes too. Ignore those */
94 if (task != mach_task_self())
97 /* Get fault information and the faulting thread's register contents..
98 See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_get_state.html. */
99 MACH_EXC_STATE_TYPE exc_state;
100 mach_msg_type_number_t exc_state_count = MACH_EXC_STATE_COUNT;
101 if (thread_get_state(thread, MACH_EXC_STATE_FLAVOR, (natural_t*)&exc_state,
104 /* The thread is supposed to be suspended while the exception
105 handler is called. This shouldn't fail. */
109 MACH_THREAD_STATE_TYPE thread_state;
110 mach_msg_type_number_t thread_state_count = MACH_THREAD_STATE_COUNT;
111 if (thread_get_state(thread, MACH_THREAD_STATE_FLAVOR,
112 (natural_t*)&thread_state, &thread_state_count) !=
114 /* The thread is supposed to be suspended while the exception
115 handler is called. This shouldn't fail. */
119 MACH_FLOAT_STATE_TYPE float_state;
120 mach_msg_type_number_t float_state_count = MACH_FLOAT_STATE_COUNT;
121 if (thread_get_state(thread, MACH_FLOAT_STATE_FLAVOR,
122 (natural_t*)&float_state, &float_state_count) !=
124 /* The thread is supposed to be suspended while the exception
125 handler is called. This shouldn't fail. */
129 /* Modify registers so to have the thread resume executing the
131 call_fault_handler(thread, exception, code[0], &exc_state, &thread_state,
134 /* Set the faulting thread's register contents..
135 See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_set_state.html. */
136 if (thread_set_state(thread, MACH_FLOAT_STATE_FLAVOR,
137 (natural_t*)&float_state, float_state_count) !=
142 if (thread_set_state(thread, MACH_THREAD_STATE_FLAVOR,
143 (natural_t*)&thread_state, thread_state_count) !=
151 /* The main function of the thread listening for exceptions. */
152 static void* mach_exception_thread(void* arg) {
154 /* These two structures contain some private kernel data. We don't need
155 to access any of it so we don't bother defining a proper struct. The
156 correct definitions are in the xnu source code. */
157 /* Buffer for a message to be received. */
159 mach_msg_header_t head;
160 mach_msg_body_t msgh_body;
163 /* Buffer for a reply message. */
165 mach_msg_header_t head;
169 mach_msg_return_t retval;
171 /* Wait for a message on the exception port. */
173 mach_msg(&msg.head, MACH_RCV_MSG | MACH_RCV_LARGE, 0, sizeof(msg),
174 our_exception_port, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
175 if (retval != MACH_MSG_SUCCESS) {
179 /* Handle the message: Call exc_server, which will call
180 catch_exception_raise and produce a reply message. */
181 exc_server(&msg.head, &reply.head);
183 /* Send the reply. */
184 if (mach_msg(&reply.head, MACH_SEND_MSG, reply.head.msgh_size, 0,
185 MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL) !=
190 return NULL; // quiet warning
193 /* Initialize the Mach exception handler thread. */
194 void mach_initialize() {
196 exception_mask_t mask;
198 self = mach_task_self();
200 /* Allocate a port on which the thread shall listen for exceptions. */
201 if (mach_port_allocate(self, MACH_PORT_RIGHT_RECEIVE, &our_exception_port) !=
203 fatal_error("mach_port_allocate() failed", 0);
206 * http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/mach_port_insert_right.html.
208 if (mach_port_insert_right(self, our_exception_port, our_exception_port,
209 MACH_MSG_TYPE_MAKE_SEND) !=
211 fatal_error("mach_port_insert_right() failed", 0);
213 /* The exceptions we want to catch. */
214 mask = EXC_MASK_BAD_ACCESS | EXC_MASK_BAD_INSTRUCTION | EXC_MASK_ARITHMETIC;
216 /* Create the thread listening on the exception port. */
217 start_thread(mach_exception_thread, NULL);
219 /* Replace the exception port info for these exceptions with our own.
220 Note that we replace the exception port for the entire task, not only
221 for a particular thread. This has the effect that when our exception
222 port gets the message, the thread specific exception port has already
223 been asked, and we don't need to bother about it. See
224 http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html. */
225 if (task_set_exception_ports(self, mask, our_exception_port,
226 EXCEPTION_DEFAULT, MACHINE_THREAD_STATE) !=
228 fatal_error("task_set_exception_ports() failed", 0);