exception.c   [plain text]

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 */

#include <mach_kdb.h>

#include <mach/mach_types.h>
#include <mach/boolean.h>
#include <mach/kern_return.h>
#include <mach/message.h>
#include <mach/port.h>
#include <mach/mig_errors.h>
#include <mach/task.h>
#include <mach/thread_status.h>
#include <mach/exception_types.h>
#include <ipc/port.h>
#include <ipc/ipc_entry.h>
#include <ipc/ipc_object.h>
#include <ipc/ipc_notify.h>
#include <ipc/ipc_space.h>
#include <ipc/ipc_pset.h>
#include <ipc/ipc_machdep.h>
#include <kern/counters.h>
#include <kern/ipc_tt.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <kern/processor.h>
#include <kern/sched.h>
#include <kern/sched_prim.h>
#include <kern/host.h>
#include <kern/misc_protos.h>
#include <string.h>
#include <mach/exc.h>

#if	MACH_KDB
#include <ddb/db_trap.h>
#endif	/* MACH_KDB */

#if	MACH_KDB

#include <ddb/db_output.h>

#if iPSC386 || iPSC860
boolean_t debug_user_with_kdb = TRUE;
#else
boolean_t debug_user_with_kdb = FALSE;
#endif

#endif	/* MACH_KDB */

unsigned long c_thr_exc_raise = 0;
unsigned long c_thr_exc_raise_state = 0;
unsigned long c_thr_exc_raise_state_id = 0;
unsigned long c_tsk_exc_raise = 0;
unsigned long c_tsk_exc_raise_state = 0;
unsigned long c_tsk_exc_raise_state_id = 0;

/* forward declarations */
void exception_deliver(
	exception_type_t	exception,
	exception_data_t	code,
	mach_msg_type_number_t  codeCnt,
	struct exception_action *excp,
	mutex_t			*mutex);

#ifdef MACH_BSD
kern_return_t bsd_exception(
	exception_type_t	exception,
	exception_data_t	code,
	mach_msg_type_number_t  codeCnt);
#endif /* MACH_BSD */

/*
 *	Routine:	exception_deliver
 *	Purpose:
 *		Make an upcall to the exception server provided.
 *	Conditions:
 *		Nothing locked and no resources held.
 *		Called from an exception context, so
 *		thread_exception_return and thread_kdb_return
 *		are possible.
 *	Returns:
 *		If the exception was not handled by this handler
 */
void
exception_deliver(
	exception_type_t	exception,
	exception_data_t	code,
	mach_msg_type_number_t  codeCnt,
	struct exception_action *excp,
	mutex_t			*mutex)
{
	thread_t		self = current_thread();
	ipc_port_t		exc_port;
	int			behavior;
	int			flavor;
	kern_return_t		kr;

	/*
	 *  Save work if we are terminating.
	 *  Just go back to our AST handler.
	 */
	if (!self->active)
		thread_exception_return();

	/*
	 * Snapshot the exception action data under lock for consistency.
	 * Hold a reference to the port over the exception_raise_* calls
	 * so it can't be destroyed.  This seems like overkill, but keeps
	 * the port from disappearing between now and when
	 * ipc_object_copyin_from_kernel is finally called.
	 */
	mutex_lock(mutex);
	exc_port = excp->port;
	if (!IP_VALID(exc_port)) {
		mutex_unlock(mutex);
		return;
	}
	ip_lock(exc_port);
	if (!ip_active(exc_port)) {
		ip_unlock(exc_port);
		mutex_unlock(mutex);
		return;
	}
	ip_reference(exc_port);	
	exc_port->ip_srights++;
	ip_unlock(exc_port);

	flavor = excp->flavor;
	behavior = excp->behavior;
	mutex_unlock(mutex);

	switch (behavior) {
	case EXCEPTION_STATE: {
		mach_msg_type_number_t state_cnt;
		thread_state_data_t state;

		c_thr_exc_raise_state++;
		state_cnt = _MachineStateCount[flavor];
		kr = thread_getstatus(self, flavor, 
				      (thread_state_t)state,
				      &state_cnt);
		if (kr == KERN_SUCCESS) {
			kr = exception_raise_state(exc_port, exception,
						   code, codeCnt,
						   &flavor,
						   state, state_cnt,
						   state, &state_cnt);
			if (kr == MACH_MSG_SUCCESS)
				kr = thread_setstatus(self, flavor, 
						      (thread_state_t)state,
						      state_cnt);
		}

		if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
			thread_exception_return();
			/*NOTREACHED*/
		return;
	}

	case EXCEPTION_DEFAULT:
		c_thr_exc_raise++;
		kr = exception_raise(exc_port,
				retrieve_thread_self_fast(self),
				retrieve_task_self_fast(self->task),
				exception,
				code, codeCnt);

		if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
			thread_exception_return();
			/*NOTREACHED*/
		return;

	case EXCEPTION_STATE_IDENTITY: {
		mach_msg_type_number_t state_cnt;
		thread_state_data_t state;

		c_thr_exc_raise_state_id++;
		state_cnt = _MachineStateCount[flavor];
		kr = thread_getstatus(self, flavor,
				      (thread_state_t)state,
				      &state_cnt);
		if (kr == KERN_SUCCESS) {
		    kr = exception_raise_state_identity(exc_port,
				retrieve_thread_self_fast(self),
				retrieve_task_self_fast(self->task),
				exception,
				code, codeCnt,
				&flavor,
				state, state_cnt,
				state, &state_cnt);
		    if (kr == MACH_MSG_SUCCESS)
			kr = thread_setstatus(self, flavor,
					      (thread_state_t)state,
					      state_cnt);
		}

		if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
			thread_exception_return();
			/*NOTREACHED*/
		return;
	}
	
	default:
		panic ("bad exception behavior!");
	}/* switch */
}

/*
 *	Routine:	exception
 *	Purpose:
 *		The current thread caught an exception.
 *		We make an up-call to the thread's exception server.
 *	Conditions:
 *		Nothing locked and no resources held.
 *		Called from an exception context, so
 *		thread_exception_return and thread_kdb_return
 *		are possible.
 *	Returns:
 *		Doesn't return.
 */
void
exception_triage(
	exception_type_t	exception,
	exception_data_t	code,
	mach_msg_type_number_t  codeCnt)
{
	thread_t		thread;
	task_t			task;
	host_priv_t		host_priv;
	struct exception_action *excp;
	mutex_t			*mutex;

	assert(exception != EXC_RPC_ALERT);

	if (exception == KERN_SUCCESS)
		panic("exception");

	/*
	 * Try to raise the exception at the activation level.
	 */
	thread = current_thread();
	mutex = mutex_addr(thread->mutex);
	excp = &thread->exc_actions[exception];
	exception_deliver(exception, code, codeCnt, excp, mutex);

	/*
	 * Maybe the task level will handle it.
	 */
	task = current_task();
	mutex = mutex_addr(task->lock);
	excp = &task->exc_actions[exception];
	exception_deliver(exception, code, codeCnt, excp, mutex);

	/*
	 * How about at the host level?
	 */
	host_priv = host_priv_self();
	mutex = mutex_addr(host_priv->lock);
	excp = &host_priv->exc_actions[exception];
	exception_deliver(exception, code, codeCnt, excp, mutex);

	/*
	 * Nobody handled it, terminate the task.
	 */

#if	MACH_KDB
	if (debug_user_with_kdb) {
		/*
		 *	Debug the exception with kdb.
		 *	If kdb handles the exception,
		 *	then thread_kdb_return won't return.
		 */
		db_printf("No exception server, calling kdb...\n");
		thread_kdb_return();
	}
#endif	/* MACH_KDB */

	(void) task_terminate(task);
	thread_exception_return();
	/*NOTREACHED*/
}

kern_return_t
bsd_exception(
	exception_type_t	exception,
	exception_data_t	code,
	mach_msg_type_number_t  codeCnt)
{
	task_t			task;
	struct exception_action *excp;
	mutex_t			*mutex;
	thread_t		self = current_thread();
	ipc_port_t		exc_port;
	int			behavior;
	int			flavor;
	kern_return_t		kr;

	/*
	 * Maybe the task level will handle it.
	 */
	task = current_task();
	mutex = mutex_addr(task->lock);
	excp = &task->exc_actions[exception];

	/*
	 *  Save work if we are terminating.
	 *  Just go back to our AST handler.
	 */
	if (!self->active) {
		return(KERN_FAILURE);
	}

	/*
	 * Snapshot the exception action data under lock for consistency.
	 * Hold a reference to the port over the exception_raise_* calls
	 * so it can't be destroyed.  This seems like overkill, but keeps
	 * the port from disappearing between now and when
	 * ipc_object_copyin_from_kernel is finally called.
	 */
	mutex_lock(mutex);
	exc_port = excp->port;
	if (!IP_VALID(exc_port)) {
		mutex_unlock(mutex);
		return(KERN_FAILURE);
	}
	ip_lock(exc_port);
	if (!ip_active(exc_port)) {
		ip_unlock(exc_port);
		mutex_unlock(mutex);
		return(KERN_FAILURE);
	}
	ip_reference(exc_port);	
	exc_port->ip_srights++;
	ip_unlock(exc_port);

	flavor = excp->flavor;
	behavior = excp->behavior;
	mutex_unlock(mutex);

	switch (behavior) {
	case EXCEPTION_STATE: {
		mach_msg_type_number_t state_cnt;
		thread_state_data_t state;

		c_thr_exc_raise_state++;
		state_cnt = _MachineStateCount[flavor];
		kr = thread_getstatus(self, flavor, 
				      (thread_state_t)state,
				      &state_cnt);
		if (kr == KERN_SUCCESS) {
			kr = exception_raise_state(exc_port, exception,
						   code, codeCnt,
						   &flavor,
						   state, state_cnt,
						   state, &state_cnt);
			if (kr == MACH_MSG_SUCCESS)
				kr = thread_setstatus(self, flavor, 
						      (thread_state_t)state,
						      state_cnt);
		}

		if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
			return(KERN_SUCCESS);

		return(KERN_FAILURE);
	}

	case EXCEPTION_DEFAULT:
		c_thr_exc_raise++;
		kr = exception_raise(exc_port,
				retrieve_thread_self_fast(self),
				retrieve_task_self_fast(self->task),
				exception,
				code, codeCnt);

		if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
			return(KERN_SUCCESS);
		return(KERN_FAILURE);

	case EXCEPTION_STATE_IDENTITY: {
		mach_msg_type_number_t state_cnt;
		thread_state_data_t state;

		c_thr_exc_raise_state_id++;
		state_cnt = _MachineStateCount[flavor];
		kr = thread_getstatus(self, flavor,
				      (thread_state_t)state,
				      &state_cnt);
		if (kr == KERN_SUCCESS) {
		    kr = exception_raise_state_identity(exc_port,
				retrieve_thread_self_fast(self),
				retrieve_task_self_fast(self->task),
				exception,
				code, codeCnt,
				&flavor,
				state, state_cnt,
				state, &state_cnt);
		    if (kr == MACH_MSG_SUCCESS)
			kr = thread_setstatus(self, flavor,
					      (thread_state_t)state,
					      state_cnt);
		}

		if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED)
			return(KERN_SUCCESS);
		return(KERN_FAILURE);
	}
	
	default:
		
		return(KERN_FAILURE);
	}/* switch */
	return(KERN_FAILURE);
}




/*
 *	Handle interface for special perfomance monitoring
 *	This is a special case of the host exception handler
 */

kern_return_t sys_perf_notify(struct task *task,
	exception_data_t code,
	mach_msg_type_number_t codeCnt)
{
	host_priv_t		hostp;
	struct exception_action *excp;
	thread_t		thread = current_thread();
	ipc_port_t		xport;
	kern_return_t	ret;
	wait_interrupt_t	wsave;

	hostp = host_priv_self();				/* Get the host privileged ports */
	excp = &hostp->exc_actions[EXC_RPC_ALERT];	/* Point to the RPC_ALERT action */

	mutex_lock(&hostp->lock);				/* Lock the priv port */
	xport = excp->port;						/* Get the port for this exception */
	if (!IP_VALID(xport)) {					/* Is it valid? */
		mutex_unlock(&hostp->lock);			/* Unlock */
		return(KERN_FAILURE);				/* Go away... */
	}

	ip_lock(xport);							/* Lock the exception port */
	if (!ip_active(xport)) {				/* and is it active? */
		ip_unlock(xport);					/* Nope, fail */
		mutex_unlock(&hostp->lock);			/* Unlock */
		return(KERN_FAILURE);				/* Go away... */
	}

	if (task->itk_space == xport->data.receiver) {	/* Are we trying to send to ourselves? */
		ip_unlock(xport);					/* Yes, fail */
		mutex_unlock(&hostp->lock);			/* Unlock */
		return(KERN_FAILURE);				/* Go away... */
	}
	
	ip_reference(xport);					/* Bump reference so it doesn't go away */
	xport->ip_srights++;					/* Bump send rights */
	ip_unlock(xport);						/* We can unlock it now */

	mutex_unlock(&hostp->lock);				/* All done with the lock */

	wsave = thread_interrupt_level(THREAD_UNINT);	/* Make sure we aren't aborted here */
	
	ret = exception_raise(xport,			/* Send the exception to the perf handler */
		retrieve_thread_self_fast(thread),		/* Not always the dying guy */
		retrieve_task_self_fast(thread->task),	/* Not always the dying guy */
		EXC_RPC_ALERT,						/* Unused exception type until now */
		code, codeCnt);	
		
	(void)thread_interrupt_level(wsave);	/* Restore interrupt level */			

	return(ret);							/* Tell caller how it went */
}