[apple/xnu.git] / osfmk / kern / wait_queue.h

/*
 * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#ifdef	KERNEL_PRIVATE

#ifndef _KERN_WAIT_QUEUE_H_
#define _KERN_WAIT_QUEUE_H_

#include <mach/mach_types.h>
#include <mach/sync_policy.h>
#include <mach/kern_return.h>		/* for kern_return_t */

#include <kern/kern_types.h>		/* for wait_queue_t */
#include <kern/queue.h>

#include <sys/cdefs.h>

#ifdef	MACH_KERNEL_PRIVATE

#include <kern/lock.h>
#include <mach/branch_predicates.h>

#include <machine/cpu_number.h>
#include <machine/machine_routines.h> /* machine_timeout_suspended() */
/*
 *	wait_queue_t
 *	This is the definition of the common event wait queue
 *	that the scheduler APIs understand.  It is used
 *	internally by the gerneralized event waiting mechanism
 *	(assert_wait), and also for items that maintain their
 *	own wait queues (such as ports and semaphores).
 *
 *	It is not published to other kernel components.  They
 *	can create wait queues by calling wait_queue_alloc.
 *
 *	NOTE:  Hardware locks are used to protect event wait
 *	queues since interrupt code is free to post events to
 *	them.
 */
typedef struct wait_queue {
    unsigned int                    /* flags */
    /* boolean_t */	wq_type:16,		/* only public field */
					wq_fifo:1,		/* fifo wakeup policy? */
					wq_prepost:1,	/* waitq supports prepost? set only */
					:0;				/* force to long boundary */
    hw_lock_data_t	wq_interlock;	/* interlock */
    queue_head_t	wq_queue;		/* queue of elements */
} WaitQueue;

/*
 *	wait_queue_set_t
 *	This is the common definition for a set wait queue.
 *	These can be linked as members/elements of multiple regular
 *	wait queues.  They have an additional set of linkages to
 *	identify the linkage structures that point to them.
 */
typedef struct wait_queue_set {
	WaitQueue		wqs_wait_queue; /* our wait queue */
	queue_head_t	wqs_setlinks;	/* links from set perspective */
	queue_head_t	wqs_preposts;	/* preposted links */
} WaitQueueSet;

#define wqs_type		wqs_wait_queue.wq_type
#define wqs_fifo		wqs_wait_queue.wq_fifo
#define wqs_prepost	wqs_wait_queue.wq_prepost
#define wqs_queue		wqs_wait_queue.wq_queue

/*
 *	wait_queue_element_t
 *	This structure describes the elements on an event wait
 *	queue.  It is the common first fields in a thread shuttle
 *	and wait_queue_link_t.  In that way, a wait queue can
 *	consist of both thread shuttle elements and links off of
 *	to other (set) wait queues.
 *
 *	WARNING: These fields correspond to fields in the thread
 *	shuttle (run queue links and run queue pointer). Any change in
 *	the layout here will have to be matched with a change there.
 */
typedef struct wait_queue_element {
	queue_chain_t	wqe_links;	/* link of elements on this queue */
	void *			wqe_type;	/* Identifies link vs. thread */
	wait_queue_t	wqe_queue;	/* queue this element is on */
} WaitQueueElement;

typedef WaitQueueElement *wait_queue_element_t;

/*
 *	wait_queue_link_t
 *	Specialized wait queue element type for linking set
 *	event waits queues onto a wait queue.  In this way, an event
 *	can be constructed so that any thread waiting on any number
 *	of associated wait queues can handle the event, while letting
 *	the thread only be linked on the single wait queue it blocked on.
 *
 *	One use: ports in multiple portsets.  Each thread is queued up
 *	on the portset that it specifically blocked on during a receive
 *	operation.  Each port's event queue links in all the portset
 *	event queues of which it is a member.  An IPC event post associated
 *	with that port may wake up any thread from any of those portsets,
 *	or one that was waiting locally on the port itself.
 */
typedef struct _wait_queue_link {
	WaitQueueElement		wql_element;	/* element on master */
	queue_chain_t			wql_setlinks;	/* element on set */
	queue_chain_t			wql_preposts;	/* element on set prepost list */
    wait_queue_set_t		wql_setqueue;	/* set queue */
} WaitQueueLink;

#define wql_links wql_element.wqe_links
#define wql_type  wql_element.wqe_type
#define wql_queue wql_element.wqe_queue

#define _WAIT_QUEUE_inited			0xf1d0
#define _WAIT_QUEUE_SET_inited		0xf1d1

#define wait_queue_is_queue(wq)	\
	((wq)->wq_type == _WAIT_QUEUE_inited)

#define wait_queue_is_set(wqs)	\
	((wqs)->wqs_type == _WAIT_QUEUE_SET_inited)

#define wait_queue_is_valid(wq)	\
	(((wq)->wq_type & ~1) == _WAIT_QUEUE_inited)

#define wait_queue_empty(wq)	(queue_empty(&(wq)->wq_queue))

#define wait_queue_held(wq)		(hw_lock_held(&(wq)->wq_interlock))
#define wait_queue_lock_try(wq) (hw_lock_try(&(wq)->wq_interlock))

/* For x86, the hardware timeout is in TSC units. */
#if defined(i386) || defined(x86_64)
#define	hwLockTimeOut LockTimeOutTSC
#else
#define	hwLockTimeOut LockTimeOut
#endif
/*
 * Double the standard lock timeout, because wait queues tend
 * to iterate over a number of threads - locking each.  If there is
 * a problem with a thread lock, it normally times out at the wait
 * queue level first, hiding the real problem.
 */

static inline void wait_queue_lock(wait_queue_t wq) {
	if (__improbable(hw_lock_to(&(wq)->wq_interlock, hwLockTimeOut * 2) == 0)) {
		boolean_t wql_acquired = FALSE;

		while (machine_timeout_suspended()) {
#if	defined(__i386__) || defined(__x86_64__)
/*
 * i386/x86_64 return with preemption disabled on a timeout for
 * diagnostic purposes.
 */
			mp_enable_preemption();
#endif
			if ((wql_acquired = hw_lock_to(&(wq)->wq_interlock, hwLockTimeOut * 2)))
				break;
		}
		if (wql_acquired == FALSE)
			panic("wait queue deadlock - wq=%p, cpu=%d\n", wq, cpu_number());
	}
}

static inline void wait_queue_unlock(wait_queue_t wq) {
	assert(wait_queue_held(wq));
	hw_lock_unlock(&(wq)->wq_interlock);
}

#define wqs_lock(wqs)		wait_queue_lock(&(wqs)->wqs_wait_queue)
#define wqs_unlock(wqs)		wait_queue_unlock(&(wqs)->wqs_wait_queue)
#define wqs_lock_try(wqs)	wait_queue__try_lock(&(wqs)->wqs_wait_queue)
#define wqs_is_preposted(wqs)	((wqs)->wqs_prepost && !queue_empty(&(wqs)->wqs_preposts))

#define wql_is_preposted(wql)	((wql)->wql_preposts.next != NULL)
#define wql_clear_prepost(wql)  ((wql)->wql_preposts.next = (wql)->wql_preposts.prev = NULL)

#define wait_queue_assert_possible(thread) \
			((thread)->wait_queue == WAIT_QUEUE_NULL)

/* bootstrap interface - can allocate/link wait_queues and sets after calling this */
__private_extern__ void wait_queue_bootstrap(void);

/******** Decomposed interfaces (to build higher level constructs) ***********/

/* assert intent to wait on a locked wait queue */
__private_extern__ wait_result_t wait_queue_assert_wait64_locked(
			wait_queue_t wait_queue,
			event64_t wait_event,
			wait_interrupt_t interruptible,
			uint64_t deadline,
			thread_t thread);

/* pull a thread from its wait queue */
__private_extern__ void wait_queue_pull_thread_locked(
			wait_queue_t wait_queue,
			thread_t thread,
			boolean_t unlock);

/* wakeup all threads waiting for a particular event on locked queue */
__private_extern__ kern_return_t wait_queue_wakeup64_all_locked(
			wait_queue_t wait_queue,
			event64_t wake_event,
			wait_result_t result,
			boolean_t unlock);

/* wakeup one thread waiting for a particular event on locked queue */
__private_extern__ kern_return_t wait_queue_wakeup64_one_locked(
			wait_queue_t wait_queue,
			event64_t wake_event,
			wait_result_t result,
			boolean_t unlock);

/* return identity of a thread awakened for a particular <wait_queue,event> */
__private_extern__ thread_t wait_queue_wakeup64_identity_locked(
			wait_queue_t wait_queue,
			event64_t wake_event,
			wait_result_t result,
			boolean_t unlock);

/* wakeup thread iff its still waiting for a particular event on locked queue */
__private_extern__ kern_return_t wait_queue_wakeup64_thread_locked(
			wait_queue_t wait_queue,
			event64_t wake_event,
			thread_t thread,
			wait_result_t result,
			boolean_t unlock);

__private_extern__ uint32_t num_wait_queues;
__private_extern__ struct wait_queue *wait_queues;
/* The Jenkins "one at a time" hash.
 * TBD: There may be some value to unrolling here,
 * depending on the architecture.
 */
static inline uint32_t wq_hash(char *key)
{
	uint32_t hash = 0;
	size_t i, length = sizeof(char *);

	for (i = 0; i < length; i++) {
		hash += key[i];
		hash += (hash << 10);
		hash ^= (hash >> 6);
	}
 
	hash += (hash << 3);
	hash ^= (hash >> 11);
	hash += (hash << 15);

	hash &= (num_wait_queues - 1);
	return hash;
}

#define	wait_hash(event) wq_hash((char *)&event) 

#endif	/* MACH_KERNEL_PRIVATE */

__BEGIN_DECLS

/******** Semi-Public interfaces (not a part of a higher construct) ************/

extern unsigned int wait_queue_set_size(void);
extern unsigned int wait_queue_link_size(void);

extern kern_return_t wait_queue_init(
			wait_queue_t wait_queue,
			int policy);

extern wait_queue_set_t wait_queue_set_alloc(
			int policy);

extern kern_return_t wait_queue_set_init(
			wait_queue_set_t set_queue,
			int policy);

extern kern_return_t wait_queue_set_free(
			wait_queue_set_t set_queue);

extern wait_queue_link_t wait_queue_link_alloc(
			int policy);

extern kern_return_t wait_queue_link_free(
			wait_queue_link_t link_element);

extern kern_return_t wait_queue_link(
			wait_queue_t wait_queue,
			wait_queue_set_t set_queue);

extern kern_return_t wait_queue_link_noalloc(
			wait_queue_t wait_queue,
			wait_queue_set_t set_queue,
			wait_queue_link_t link);

extern boolean_t wait_queue_member(
			wait_queue_t wait_queue,
			wait_queue_set_t set_queue);

extern kern_return_t wait_queue_unlink(
			wait_queue_t wait_queue,
			wait_queue_set_t set_queue);

extern kern_return_t wait_queue_unlink_all(
			wait_queue_t wait_queue);

extern kern_return_t wait_queue_set_unlink_all(
			wait_queue_set_t set_queue);

#ifdef XNU_KERNEL_PRIVATE
extern kern_return_t wait_queue_set_unlink_one(
			wait_queue_set_t set_queue,
			wait_queue_link_t link);

extern kern_return_t wait_queue_unlink_nofree(
			wait_queue_t wait_queue,
			wait_queue_set_t set_queue,
			wait_queue_link_t *wqlp);

extern kern_return_t wait_queue_unlink_all_nofree(
			wait_queue_t wait_queue,
			queue_t links);

extern kern_return_t wait_queue_set_unlink_all_nofree(
			wait_queue_set_t set_queue,
			queue_t links);

extern wait_queue_link_t wait_queue_link_allocate(void);

#endif /* XNU_KERNEL_PRIVATE */

/* legacy API */
kern_return_t wait_queue_sub_init(
			wait_queue_set_t set_queue,
			int policy);

kern_return_t wait_queue_sub_clearrefs(
			wait_queue_set_t wq_set);

extern kern_return_t wait_subqueue_unlink_all(
			wait_queue_set_t set_queue);

extern wait_queue_t wait_queue_alloc(
			int policy);

extern kern_return_t wait_queue_free(
			wait_queue_t wait_queue);

/* assert intent to wait on <wait_queue,event64> pair */
extern wait_result_t wait_queue_assert_wait64(
			wait_queue_t wait_queue,
			event64_t wait_event,
			wait_interrupt_t interruptible,
			uint64_t deadline);

/* wakeup the most appropriate thread waiting on <wait_queue,event64> pair */
extern kern_return_t wait_queue_wakeup64_one(
			wait_queue_t wait_queue,
			event64_t wake_event,
			wait_result_t result);

/* wakeup all the threads waiting on <wait_queue,event64> pair */
extern kern_return_t wait_queue_wakeup64_all(
			wait_queue_t wait_queue,
			event64_t wake_event,
			wait_result_t result);

/* wakeup a specified thread waiting iff waiting on <wait_queue,event64> pair */
extern kern_return_t wait_queue_wakeup64_thread(
			wait_queue_t wait_queue,
			event64_t wake_event,
			thread_t thread,
			wait_result_t result);

/*
 * Compatibility Wait Queue APIs based on pointer events instead of 64bit
 * integer events.
 */

/* assert intent to wait on <wait_queue,event> pair */
extern wait_result_t wait_queue_assert_wait(
			wait_queue_t wait_queue,
			event_t wait_event,
			wait_interrupt_t interruptible,
			uint64_t deadline);

/* wakeup the most appropriate thread waiting on <wait_queue,event> pair */
extern kern_return_t wait_queue_wakeup_one(
			wait_queue_t wait_queue,
			event_t wake_event,
			wait_result_t result,
	                int priority);

/* wakeup all the threads waiting on <wait_queue,event> pair */
extern kern_return_t wait_queue_wakeup_all(
			wait_queue_t wait_queue,
			event_t wake_event,
			wait_result_t result);

/* wakeup a specified thread waiting iff waiting on <wait_queue,event> pair */
extern kern_return_t wait_queue_wakeup_thread(
			wait_queue_t wait_queue,
			event_t wake_event,
			thread_t thread,
			wait_result_t result);

__END_DECLS

#endif	/* _KERN_WAIT_QUEUE_H_ */

#endif	/* KERNEL_PRIVATE */
Commit	Line	Data
1c79356b	1	/*
91447636	2	* Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
1c79356b	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
8f6c56a5	14	*
2d21ac55 A	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b	27	*/
1c79356b	28
91447636	29	#ifdef KERNEL_PRIVATE
9bccf70c	30
91447636 A	31	#ifndef _KERN_WAIT_QUEUE_H_
91447636 A	32	#define _KERN_WAIT_QUEUE_H_
9bccf70c	33
91447636	34	#include <mach/mach_types.h>
1c79356b	35	#include <mach/sync_policy.h>
0b4e3aa0	36	#include <mach/kern_return.h> /* for kern_return_t */
1c79356b	37
9bccf70c	38	#include <kern/kern_types.h> /* for wait_queue_t */
316670eb	39	#include <kern/queue.h>
9bccf70c	40
91447636 A	41	#include <sys/cdefs.h>
	42
	43	#ifdef MACH_KERNEL_PRIVATE
1c79356b A	44
1c79356b A	45	#include <kern/lock.h>
6d2010ae	46	#include <mach/branch_predicates.h>
9bccf70c	47
060df5ea A	48	#include <machine/cpu_number.h>
060df5ea A	49	#include <machine/machine_routines.h> /* machine_timeout_suspended() */
1c79356b A	50	/*
	51	* wait_queue_t
	52	* This is the definition of the common event wait queue
	53	* that the scheduler APIs understand. It is used
	54	* internally by the gerneralized event waiting mechanism
	55	* (assert_wait), and also for items that maintain their
	56	* own wait queues (such as ports and semaphores).
	57	*
	58	* It is not published to other kernel components. They
	59	* can create wait queues by calling wait_queue_alloc.
	60	*
	61	* NOTE: Hardware locks are used to protect event wait
	62	* queues since interrupt code is free to post events to
	63	* them.
	64	*/
	65	typedef struct wait_queue {
9bccf70c A	66	unsigned int /* flags */
	67	/* boolean_t / wq_type:16, / only public field */
	68	wq_fifo:1, /* fifo wakeup policy? */
b0d623f7	69	wq_prepost:1, /* waitq supports prepost? set only */
9bccf70c	70	:0; /* force to long boundary */
1c79356b	71	hw_lock_data_t wq_interlock; /* interlock */
9bccf70c	72	queue_head_t wq_queue; /* queue of elements */
1c79356b A	73	} WaitQueue;
	74
	75	/*
9bccf70c A	76	* wait_queue_set_t
9bccf70c A	77	* This is the common definition for a set wait queue.
1c79356b A	78	* These can be linked as members/elements of multiple regular
	79	* wait queues. They have an additional set of linkages to
	80	* identify the linkage structures that point to them.
	81	*/
9bccf70c A	82	typedef struct wait_queue_set {
	83	WaitQueue wqs_wait_queue; /* our wait queue */
	84	queue_head_t wqs_setlinks; /* links from set perspective */
b0d623f7	85	queue_head_t wqs_preposts; /* preposted links */
9bccf70c	86	} WaitQueueSet;
1c79356b	87
9bccf70c A	88	#define wqs_type wqs_wait_queue.wq_type
9bccf70c A	89	#define wqs_fifo wqs_wait_queue.wq_fifo
b0d623f7	90	#define wqs_prepost wqs_wait_queue.wq_prepost
9bccf70c	91	#define wqs_queue wqs_wait_queue.wq_queue
1c79356b A	92
	93	/*
	94	* wait_queue_element_t
	95	* This structure describes the elements on an event wait
	96	* queue. It is the common first fields in a thread shuttle
	97	* and wait_queue_link_t. In that way, a wait queue can
	98	* consist of both thread shuttle elements and links off of
9bccf70c	99	* to other (set) wait queues.
1c79356b	100	*
9bccf70c A	101	* WARNING: These fields correspond to fields in the thread
9bccf70c A	102	* shuttle (run queue links and run queue pointer). Any change in
1c79356b A	103	* the layout here will have to be matched with a change there.
	104	*/
	105	typedef struct wait_queue_element {
	106	queue_chain_t wqe_links; /* link of elements on this queue */
9bccf70c	107	void * wqe_type; /* Identifies link vs. thread */
1c79356b	108	wait_queue_t wqe_queue; /* queue this element is on */
9bccf70c	109	} WaitQueueElement;
1c79356b	110
9bccf70c	111	typedef WaitQueueElement *wait_queue_element_t;
0b4e3aa0	112
1c79356b A	113	/*
1c79356b A	114	* wait_queue_link_t
9bccf70c	115	* Specialized wait queue element type for linking set
1c79356b A	116	* event waits queues onto a wait queue. In this way, an event
	117	* can be constructed so that any thread waiting on any number
	118	* of associated wait queues can handle the event, while letting
	119	* the thread only be linked on the single wait queue it blocked on.
	120	*
	121	* One use: ports in multiple portsets. Each thread is queued up
	122	* on the portset that it specifically blocked on during a receive
	123	* operation. Each port's event queue links in all the portset
	124	* event queues of which it is a member. An IPC event post associated
	125	* with that port may wake up any thread from any of those portsets,
	126	* or one that was waiting locally on the port itself.
	127	*/
2d21ac55	128	typedef struct _wait_queue_link {
9bccf70c A	129	WaitQueueElement wql_element; /* element on master */
9bccf70c A	130	queue_chain_t wql_setlinks; /* element on set */
b0d623f7	131	queue_chain_t wql_preposts; /* element on set prepost list */
9bccf70c	132	wait_queue_set_t wql_setqueue; /* set queue */
0b4e3aa0 A	133	} WaitQueueLink;
0b4e3aa0 A	134
1c79356b	135	#define wql_links wql_element.wqe_links
9bccf70c	136	#define wql_type wql_element.wqe_type
1c79356b	137	#define wql_queue wql_element.wqe_queue
0b4e3aa0	138
9bccf70c A	139	#define _WAIT_QUEUE_inited 0xf1d0
9bccf70c A	140	#define _WAIT_QUEUE_SET_inited 0xf1d1
0b4e3aa0	141
9bccf70c A	142	#define wait_queue_is_queue(wq) \
9bccf70c A	143	((wq)->wq_type == _WAIT_QUEUE_inited)
1c79356b	144
9bccf70c A	145	#define wait_queue_is_set(wqs) \
9bccf70c A	146	((wqs)->wqs_type == _WAIT_QUEUE_SET_inited)
1c79356b	147
9bccf70c A	148	#define wait_queue_is_valid(wq) \
9bccf70c A	149	(((wq)->wq_type & ~1) == _WAIT_QUEUE_inited)
1c79356b	150
9bccf70c	151	#define wait_queue_empty(wq) (queue_empty(&(wq)->wq_queue))
2d21ac55	152
9bccf70c A	153	#define wait_queue_held(wq) (hw_lock_held(&(wq)->wq_interlock))
9bccf70c A	154	#define wait_queue_lock_try(wq) (hw_lock_try(&(wq)->wq_interlock))
1c79356b	155
2d21ac55	156	/* For x86, the hardware timeout is in TSC units. */
6d2010ae	157	#if defined(i386) \|\| defined(x86_64)
2d21ac55 A	158	#define hwLockTimeOut LockTimeOutTSC
	159	#else
	160	#define hwLockTimeOut LockTimeOut
	161	#endif
9bccf70c A	162	/*
	163	* Double the standard lock timeout, because wait queues tend
	164	* to iterate over a number of threads - locking each. If there is
	165	* a problem with a thread lock, it normally times out at the wait
	166	* queue level first, hiding the real problem.
	167	*/
1c79356b	168
0c530ab8	169	static inline void wait_queue_lock(wait_queue_t wq) {
6d2010ae	170	if (__improbable(hw_lock_to(&(wq)->wq_interlock, hwLockTimeOut * 2) == 0)) {
060df5ea	171	boolean_t wql_acquired = FALSE;
6d2010ae	172
060df5ea A	173	while (machine_timeout_suspended()) {
	174	#if defined(__i386__) \|\| defined(__x86_64__)
	175	/*
	176	* i386/x86_64 return with preemption disabled on a timeout for
	177	* diagnostic purposes.
	178	*/
	179	mp_enable_preemption();
	180	#endif
	181	if ((wql_acquired = hw_lock_to(&(wq)->wq_interlock, hwLockTimeOut * 2)))
	182	break;
	183	}
060df5ea A	184	if (wql_acquired == FALSE)
	185	panic("wait queue deadlock - wq=%p, cpu=%d\n", wq, cpu_number());
	186	}
0c530ab8	187	}
060df5ea	188
0c530ab8 A	189	static inline void wait_queue_unlock(wait_queue_t wq) {
0c530ab8 A	190	assert(wait_queue_held(wq));
2d21ac55	191	hw_lock_unlock(&(wq)->wq_interlock);
0c530ab8	192	}
1c79356b	193
9bccf70c A	194	#define wqs_lock(wqs) wait_queue_lock(&(wqs)->wqs_wait_queue)
	195	#define wqs_unlock(wqs) wait_queue_unlock(&(wqs)->wqs_wait_queue)
	196	#define wqs_lock_try(wqs) wait_queue__try_lock(&(wqs)->wqs_wait_queue)
b0d623f7 A	197	#define wqs_is_preposted(wqs) ((wqs)->wqs_prepost && !queue_empty(&(wqs)->wqs_preposts))
	198
	199	#define wql_is_preposted(wql) ((wql)->wql_preposts.next != NULL)
	200	#define wql_clear_prepost(wql) ((wql)->wql_preposts.next = (wql)->wql_preposts.prev = NULL)
1c79356b A	201
	202	#define wait_queue_assert_possible(thread) \
	203	((thread)->wait_queue == WAIT_QUEUE_NULL)
	204
b0d623f7 A	205	/* bootstrap interface - can allocate/link wait_queues and sets after calling this */
	206	__private_extern__ void wait_queue_bootstrap(void);
	207
1c79356b A	208	/****** Decomposed interfaces (to build higher level constructs) *********/
1c79356b A	209
1c79356b	210	/* assert intent to wait on a locked wait queue */
9bccf70c	211	__private_extern__ wait_result_t wait_queue_assert_wait64_locked(
1c79356b	212	wait_queue_t wait_queue,
9bccf70c A	213	event64_t wait_event,
9bccf70c A	214	wait_interrupt_t interruptible,
91447636	215	uint64_t deadline,
55e303ae	216	thread_t thread);
1c79356b	217
2d21ac55	218	/* pull a thread from its wait queue */
9bccf70c	219	__private_extern__ void wait_queue_pull_thread_locked(
1c79356b A	220	wait_queue_t wait_queue,
	221	thread_t thread,
	222	boolean_t unlock);
	223
	224	/* wakeup all threads waiting for a particular event on locked queue */
9bccf70c	225	__private_extern__ kern_return_t wait_queue_wakeup64_all_locked(
1c79356b	226	wait_queue_t wait_queue,
9bccf70c A	227	event64_t wake_event,
9bccf70c A	228	wait_result_t result,
1c79356b A	229	boolean_t unlock);
	230
	231	/* wakeup one thread waiting for a particular event on locked queue */
9bccf70c	232	__private_extern__ kern_return_t wait_queue_wakeup64_one_locked(
1c79356b	233	wait_queue_t wait_queue,
9bccf70c A	234	event64_t wake_event,
9bccf70c A	235	wait_result_t result,
1c79356b A	236	boolean_t unlock);
1c79356b A	237
1c79356b	238	/* return identity of a thread awakened for a particular <wait_queue,event> */
9bccf70c	239	__private_extern__ thread_t wait_queue_wakeup64_identity_locked(
1c79356b	240	wait_queue_t wait_queue,
9bccf70c A	241	event64_t wake_event,
9bccf70c A	242	wait_result_t result,
1c79356b A	243	boolean_t unlock);
	244
	245	/* wakeup thread iff its still waiting for a particular event on locked queue */
9bccf70c	246	__private_extern__ kern_return_t wait_queue_wakeup64_thread_locked(
1c79356b	247	wait_queue_t wait_queue,
9bccf70c	248	event64_t wake_event,
1c79356b	249	thread_t thread,
9bccf70c	250	wait_result_t result,
1c79356b A	251	boolean_t unlock);
1c79356b A	252
b0d623f7 A	253	__private_extern__ uint32_t num_wait_queues;
	254	__private_extern__ struct wait_queue *wait_queues;
	255	/* The Jenkins "one at a time" hash.
	256	* TBD: There may be some value to unrolling here,
	257	* depending on the architecture.
	258	*/
	259	static inline uint32_t wq_hash(char *key)
	260	{
	261	uint32_t hash = 0;
	262	size_t i, length = sizeof(char *);
	263
	264	for (i = 0; i < length; i++) {
	265	hash += key[i];
	266	hash += (hash << 10);
	267	hash ^= (hash >> 6);
	268	}
	269
	270	hash += (hash << 3);
	271	hash ^= (hash >> 11);
	272	hash += (hash << 15);
	273
316670eb	274	hash &= (num_wait_queues - 1);
b0d623f7 A	275	return hash;
	276	}
	277
316670eb	278	#define wait_hash(event) wq_hash((char *)&event)
b0d623f7	279
91447636 A	280	#endif /* MACH_KERNEL_PRIVATE */
	281
	282	__BEGIN_DECLS
1c79356b	283
9bccf70c A	284	/****** Semi-Public interfaces (not a part of a higher construct) **********/
9bccf70c A	285
91447636 A	286	extern unsigned int wait_queue_set_size(void);
	287	extern unsigned int wait_queue_link_size(void);
	288
9bccf70c A	289	extern kern_return_t wait_queue_init(
	290	wait_queue_t wait_queue,
	291	int policy);
	292
	293	extern wait_queue_set_t wait_queue_set_alloc(
	294	int policy);
	295
91447636 A	296	extern kern_return_t wait_queue_set_init(
	297	wait_queue_set_t set_queue,
	298	int policy);
	299
9bccf70c A	300	extern kern_return_t wait_queue_set_free(
	301	wait_queue_set_t set_queue);
	302
	303	extern wait_queue_link_t wait_queue_link_alloc(
	304	int policy);
	305
	306	extern kern_return_t wait_queue_link_free(
	307	wait_queue_link_t link_element);
	308
91447636 A	309	extern kern_return_t wait_queue_link(
	310	wait_queue_t wait_queue,
	311	wait_queue_set_t set_queue);
9bccf70c	312
91447636 A	313	extern kern_return_t wait_queue_link_noalloc(
	314	wait_queue_t wait_queue,
	315	wait_queue_set_t set_queue,
	316	wait_queue_link_t link);
1c79356b	317
91447636	318	extern boolean_t wait_queue_member(
9bccf70c A	319	wait_queue_t wait_queue,
	320	wait_queue_set_t set_queue);
	321
	322	extern kern_return_t wait_queue_unlink(
	323	wait_queue_t wait_queue,
	324	wait_queue_set_t set_queue);
	325
	326	extern kern_return_t wait_queue_unlink_all(
1c79356b A	327	wait_queue_t wait_queue);
1c79356b A	328
9bccf70c A	329	extern kern_return_t wait_queue_set_unlink_all(
	330	wait_queue_set_t set_queue);
	331
6d2010ae A	332	#ifdef XNU_KERNEL_PRIVATE
	333	extern kern_return_t wait_queue_set_unlink_one(
	334	wait_queue_set_t set_queue,
	335	wait_queue_link_t link);
	336
316670eb A	337	extern kern_return_t wait_queue_unlink_nofree(
	338	wait_queue_t wait_queue,
	339	wait_queue_set_t set_queue,
	340	wait_queue_link_t *wqlp);
	341
	342	extern kern_return_t wait_queue_unlink_all_nofree(
	343	wait_queue_t wait_queue,
	344	queue_t links);
	345
	346	extern kern_return_t wait_queue_set_unlink_all_nofree(
	347	wait_queue_set_t set_queue,
	348	queue_t links);
	349
6d2010ae A	350	extern wait_queue_link_t wait_queue_link_allocate(void);
	351
	352	#endif /* XNU_KERNEL_PRIVATE */
	353
91447636 A	354	/* legacy API */
	355	kern_return_t wait_queue_sub_init(
	356	wait_queue_set_t set_queue,
	357	int policy);
	358
	359	kern_return_t wait_queue_sub_clearrefs(
	360	wait_queue_set_t wq_set);
	361
	362	extern kern_return_t wait_subqueue_unlink_all(
	363	wait_queue_set_t set_queue);
	364
	365	extern wait_queue_t wait_queue_alloc(
	366	int policy);
	367
	368	extern kern_return_t wait_queue_free(
	369	wait_queue_t wait_queue);
	370
9bccf70c A	371	/* assert intent to wait on <wait_queue,event64> pair */
	372	extern wait_result_t wait_queue_assert_wait64(
	373	wait_queue_t wait_queue,
	374	event64_t wait_event,
91447636 A	375	wait_interrupt_t interruptible,
91447636 A	376	uint64_t deadline);
9bccf70c A	377
	378	/* wakeup the most appropriate thread waiting on <wait_queue,event64> pair */
	379	extern kern_return_t wait_queue_wakeup64_one(
	380	wait_queue_t wait_queue,
	381	event64_t wake_event,
	382	wait_result_t result);
	383
	384	/* wakeup all the threads waiting on <wait_queue,event64> pair */
	385	extern kern_return_t wait_queue_wakeup64_all(
	386	wait_queue_t wait_queue,
	387	event64_t wake_event,
	388	wait_result_t result);
	389
	390	/* wakeup a specified thread waiting iff waiting on <wait_queue,event64> pair */
	391	extern kern_return_t wait_queue_wakeup64_thread(
	392	wait_queue_t wait_queue,
	393	event64_t wake_event,
	394	thread_t thread,
	395	wait_result_t result);
	396
9bccf70c A	397	/*
	398	* Compatibility Wait Queue APIs based on pointer events instead of 64bit
	399	* integer events.
	400	*/
1c79356b A	401
1c79356b A	402	/* assert intent to wait on <wait_queue,event> pair */
9bccf70c	403	extern wait_result_t wait_queue_assert_wait(
1c79356b A	404	wait_queue_t wait_queue,
1c79356b A	405	event_t wait_event,
91447636 A	406	wait_interrupt_t interruptible,
91447636 A	407	uint64_t deadline);
1c79356b A	408
1c79356b A	409	/* wakeup the most appropriate thread waiting on <wait_queue,event> pair */
9bccf70c	410	extern kern_return_t wait_queue_wakeup_one(
1c79356b A	411	wait_queue_t wait_queue,
1c79356b A	412	event_t wake_event,
6d2010ae A	413	wait_result_t result,
6d2010ae A	414	int priority);
1c79356b A	415
1c79356b A	416	/* wakeup all the threads waiting on <wait_queue,event> pair */
9bccf70c	417	extern kern_return_t wait_queue_wakeup_all(
1c79356b A	418	wait_queue_t wait_queue,
1c79356b A	419	event_t wake_event,
9bccf70c	420	wait_result_t result);
1c79356b A	421
1c79356b A	422	/* wakeup a specified thread waiting iff waiting on <wait_queue,event> pair */
9bccf70c	423	extern kern_return_t wait_queue_wakeup_thread(
1c79356b A	424	wait_queue_t wait_queue,
	425	event_t wake_event,
	426	thread_t thread,
9bccf70c A	427	wait_result_t result);
9bccf70c A	428
91447636 A	429	__END_DECLS
	430
	431	#endif /* _KERN_WAIT_QUEUE_H_ */
1c79356b	432
91447636	433	#endif /* KERNEL_PRIVATE */