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 */
18 /* The exception port on which our thread listens. */
19 mach_port_t our_exception_port;
21 /* 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(
32 exception_type_t exception,
33 exception_data_type_t code,
34 MACH_EXC_STATE_TYPE *exc_state,
35 MACH_THREAD_STATE_TYPE *thread_state,
36 MACH_FLOAT_STATE_TYPE *float_state)
38 /* There is a race condition here, but in practice an exception
39 delivered during stack frame setup/teardown or while transitioning
40 from Factor to C is a sign of things seriously gone wrong, not just
41 a divide by zero or stack underflow in the listener */
43 /* Are we in compiled Factor code? Then use the current stack pointer */
44 if(in_code_heap_p(MACH_PROGRAM_COUNTER(thread_state)))
45 signal_callstack_top = (stack_frame *)MACH_STACK_POINTER(thread_state);
46 /* Are we in C? Then use the saved callstack top */
48 signal_callstack_top = NULL;
50 MACH_STACK_POINTER(thread_state) = align_stack_pointer(MACH_STACK_POINTER(thread_state));
52 /* Now we point the program counter at the right handler function. */
53 if(exception == EXC_BAD_ACCESS)
55 signal_fault_addr = MACH_EXC_STATE_FAULT(exc_state);
56 MACH_PROGRAM_COUNTER(thread_state) = (cell)factor::memory_signal_handler_impl;
58 else if(exception == EXC_ARITHMETIC && code != MACH_EXC_INTEGER_DIV)
60 signal_fpu_status = fpu_status(mach_fpu_status(float_state));
61 mach_clear_fpu_status(float_state);
62 MACH_PROGRAM_COUNTER(thread_state) = (cell)factor::fp_signal_handler_impl;
68 case EXC_ARITHMETIC: signal_number = SIGFPE; break;
69 case EXC_BAD_INSTRUCTION: signal_number = SIGILL; break;
70 default: signal_number = SIGABRT; break;
73 MACH_PROGRAM_COUNTER(thread_state) = (cell)factor::misc_signal_handler_impl;
77 static void call_fault_handler(
79 exception_type_t exception,
80 exception_data_type_t code,
81 MACH_EXC_STATE_TYPE *exc_state,
82 MACH_THREAD_STATE_TYPE *thread_state,
83 MACH_FLOAT_STATE_TYPE *float_state)
85 THREADHANDLE thread_id = pthread_from_mach_thread_np(thread);
87 std::map<THREADHANDLE, factor_vm*>::const_iterator vm = thread_vms.find(thread_id);
88 if (vm != thread_vms.end())
89 vm->second->call_fault_handler(exception,code,exc_state,thread_state,float_state);
92 /* Handle an exception by invoking the user's fault handler and/or forwarding
93 the duty to the previously installed handlers. */
96 catch_exception_raise (mach_port_t exception_port,
99 exception_type_t exception,
100 exception_data_t code,
101 mach_msg_type_number_t code_count)
103 MACH_EXC_STATE_TYPE exc_state;
104 MACH_THREAD_STATE_TYPE thread_state;
105 MACH_FLOAT_STATE_TYPE float_state;
106 mach_msg_type_number_t exc_state_count, thread_state_count, float_state_count;
108 /* Get fault information and the faulting thread's register contents..
110 See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_get_state.html. */
111 exc_state_count = MACH_EXC_STATE_COUNT;
112 if (thread_get_state (thread, MACH_EXC_STATE_FLAVOR,
113 (natural_t *)&exc_state, &exc_state_count)
116 /* The thread is supposed to be suspended while the exception
117 handler is called. This shouldn't fail. */
121 thread_state_count = MACH_THREAD_STATE_COUNT;
122 if (thread_get_state (thread, MACH_THREAD_STATE_FLAVOR,
123 (natural_t *)&thread_state, &thread_state_count)
126 /* The thread is supposed to be suspended while the exception
127 handler is called. This shouldn't fail. */
131 float_state_count = MACH_FLOAT_STATE_COUNT;
132 if (thread_get_state (thread, MACH_FLOAT_STATE_FLAVOR,
133 (natural_t *)&float_state, &float_state_count)
136 /* The thread is supposed to be suspended while the exception
137 handler is called. This shouldn't fail. */
141 /* Modify registers so to have the thread resume executing the
143 call_fault_handler(thread,exception,code[0],&exc_state,&thread_state,&float_state);
145 /* Set the faulting thread's register contents..
147 See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_set_state.html. */
148 if (thread_set_state (thread, MACH_FLOAT_STATE_FLAVOR,
149 (natural_t *)&float_state, float_state_count)
155 if (thread_set_state (thread, MACH_THREAD_STATE_FLAVOR,
156 (natural_t *)&thread_state, thread_state_count)
165 /* The main function of the thread listening for exceptions. */
167 mach_exception_thread (void *arg)
171 /* These two structures contain some private kernel data. We don't need
172 to access any of it so we don't bother defining a proper struct. The
173 correct definitions are in the xnu source code. */
174 /* Buffer for a message to be received. */
177 mach_msg_header_t head;
178 mach_msg_body_t msgh_body;
182 /* Buffer for a reply message. */
185 mach_msg_header_t head;
190 mach_msg_return_t retval;
192 /* Wait for a message on the exception port. */
193 retval = mach_msg (&msg.head, MACH_RCV_MSG | MACH_RCV_LARGE, 0,
194 sizeof (msg), our_exception_port,
195 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
196 if (retval != MACH_MSG_SUCCESS)
201 /* Handle the message: Call exc_server, which will call
202 catch_exception_raise and produce a reply message. */
203 exc_server (&msg.head, &reply.head);
205 /* Send the reply. */
206 if (mach_msg (&reply.head, MACH_SEND_MSG, reply.head.msgh_size,
207 0, MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL)
215 /* Initialize the Mach exception handler thread. */
216 void mach_initialize ()
219 exception_mask_t mask;
221 self = mach_task_self ();
223 /* Allocate a port on which the thread shall listen for exceptions. */
224 if (mach_port_allocate (self, MACH_PORT_RIGHT_RECEIVE, &our_exception_port)
226 fatal_error("mach_port_allocate() failed",0);
228 /* See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/mach_port_insert_right.html. */
229 if (mach_port_insert_right (self, our_exception_port, our_exception_port,
230 MACH_MSG_TYPE_MAKE_SEND)
232 fatal_error("mach_port_insert_right() failed",0);
234 /* The exceptions we want to catch. */
235 mask = EXC_MASK_BAD_ACCESS | EXC_MASK_BAD_INSTRUCTION | EXC_MASK_ARITHMETIC;
237 /* Create the thread listening on the exception port. */
238 start_thread(mach_exception_thread,NULL);
240 /* Replace the exception port info for these exceptions with our own.
241 Note that we replace the exception port for the entire task, not only
242 for a particular thread. This has the effect that when our exception
243 port gets the message, the thread specific exception port has already
244 been asked, and we don't need to bother about it.
245 See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html. */
246 if (task_set_exception_ports (self, mask, our_exception_port,
247 EXCEPTION_DEFAULT, MACHINE_THREAD_STATE)
249 fatal_error("task_set_exception_ports() failed",0);