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 /* Look up the VM instance involved */
86 THREADHANDLE thread_id = pthread_from_mach_thread_np(thread);
88 std::map<THREADHANDLE, factor_vm*>::const_iterator vm = thread_vms.find(thread_id);
90 /* Handle the exception */
91 if (vm != thread_vms.end())
92 vm->second->call_fault_handler(exception,code,exc_state,thread_state,float_state);
95 /* Handle an exception by invoking the user's fault handler and/or forwarding
96 the duty to the previously installed handlers. */
99 catch_exception_raise (mach_port_t exception_port,
102 exception_type_t exception,
103 exception_data_t code,
104 mach_msg_type_number_t code_count)
106 /* 10.6 likes to report exceptions from child processes too. Ignore those */
107 if(task != mach_task_self()) return KERN_SUCCESS;
109 /* Get fault information and the faulting thread's register contents..
111 See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_get_state.html. */
112 MACH_EXC_STATE_TYPE exc_state;
113 mach_msg_type_number_t exc_state_count = MACH_EXC_STATE_COUNT;
114 if (thread_get_state (thread, MACH_EXC_STATE_FLAVOR,
115 (natural_t *)&exc_state, &exc_state_count)
118 /* The thread is supposed to be suspended while the exception
119 handler is called. This shouldn't fail. */
123 MACH_THREAD_STATE_TYPE thread_state;
124 mach_msg_type_number_t thread_state_count = MACH_THREAD_STATE_COUNT;
125 if (thread_get_state (thread, MACH_THREAD_STATE_FLAVOR,
126 (natural_t *)&thread_state, &thread_state_count)
129 /* The thread is supposed to be suspended while the exception
130 handler is called. This shouldn't fail. */
134 MACH_FLOAT_STATE_TYPE float_state;
135 mach_msg_type_number_t float_state_count = MACH_FLOAT_STATE_COUNT;
136 if (thread_get_state (thread, MACH_FLOAT_STATE_FLAVOR,
137 (natural_t *)&float_state, &float_state_count)
140 /* The thread is supposed to be suspended while the exception
141 handler is called. This shouldn't fail. */
145 /* Modify registers so to have the thread resume executing the
147 call_fault_handler(thread,exception,code[0],&exc_state,&thread_state,&float_state);
149 /* Set the faulting thread's register contents..
151 See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_set_state.html. */
152 if (thread_set_state (thread, MACH_FLOAT_STATE_FLAVOR,
153 (natural_t *)&float_state, float_state_count)
159 if (thread_set_state (thread, MACH_THREAD_STATE_FLAVOR,
160 (natural_t *)&thread_state, thread_state_count)
169 /* The main function of the thread listening for exceptions. */
171 mach_exception_thread (void *arg)
175 /* These two structures contain some private kernel data. We don't need
176 to access any of it so we don't bother defining a proper struct. The
177 correct definitions are in the xnu source code. */
178 /* Buffer for a message to be received. */
181 mach_msg_header_t head;
182 mach_msg_body_t msgh_body;
186 /* Buffer for a reply message. */
189 mach_msg_header_t head;
194 mach_msg_return_t retval;
196 /* Wait for a message on the exception port. */
197 retval = mach_msg (&msg.head, MACH_RCV_MSG | MACH_RCV_LARGE, 0,
198 sizeof (msg), our_exception_port,
199 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
200 if (retval != MACH_MSG_SUCCESS)
205 /* Handle the message: Call exc_server, which will call
206 catch_exception_raise and produce a reply message. */
207 exc_server (&msg.head, &reply.head);
209 /* Send the reply. */
210 if (mach_msg (&reply.head, MACH_SEND_MSG, reply.head.msgh_size,
211 0, MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL)
219 /* Initialize the Mach exception handler thread. */
220 void mach_initialize ()
223 exception_mask_t mask;
225 self = mach_task_self ();
227 /* Allocate a port on which the thread shall listen for exceptions. */
228 if (mach_port_allocate (self, MACH_PORT_RIGHT_RECEIVE, &our_exception_port)
230 fatal_error("mach_port_allocate() failed",0);
232 /* See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/mach_port_insert_right.html. */
233 if (mach_port_insert_right (self, our_exception_port, our_exception_port,
234 MACH_MSG_TYPE_MAKE_SEND)
236 fatal_error("mach_port_insert_right() failed",0);
238 /* The exceptions we want to catch. */
239 mask = EXC_MASK_BAD_ACCESS | EXC_MASK_BAD_INSTRUCTION | EXC_MASK_ARITHMETIC;
241 /* Create the thread listening on the exception port. */
242 start_thread(mach_exception_thread,NULL);
244 /* Replace the exception port info for these exceptions with our own.
245 Note that we replace the exception port for the entire task, not only
246 for a particular thread. This has the effect that when our exception
247 port gets the message, the thread specific exception port has already
248 been asked, and we don't need to bother about it.
249 See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html. */
250 if (task_set_exception_ports (self, mask, our_exception_port,
251 EXCEPTION_DEFAULT, MACHINE_THREAD_STATE)
253 fatal_error("task_set_exception_ports() failed",0);