[apple/xnu.git] / iokit / IOKit / i386 / IOSharedLockImp.h

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * 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. 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_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved. 
 *
 * HISTORY
 *
 */

/* 	Copyright (c) 1992 NeXT Computer, Inc.  All rights reserved. 
 *
 * EventShmemLock.h -	Shared memory area locks for use between the
 *			WindowServer and the Event Driver.
 *
 *
 * HISTORY
 * 29 April 1992    Mike Paquette at NeXT
 *      Created. 
 *
 * Multiprocessor locks used within the shared memory area between the
 * kernel and event system.  These must work in both user and kernel mode.
 * The locks are defined in an include file so they get exported to the local
 * include file area.
 *
 * This is basically a ripoff of the spin locks under the cthreads packages.
 */

#ifndef _IOKIT_IOSHAREDLOCKIMP_H
#define _IOKIT_IOSHAREDLOCKIMP_H

#include <architecture/i386/asm_help.h>

// 'Till we're building in kernel
.macro DISABLE_PREEMPTION
#ifdef KERNEL
#endif
.endmacro
.macro ENABLE_PREEMPTION
#ifdef KERNEL
#endif
.endmacro

/* 
 * void
 * ev_lock(p)
 *	int *p;
 *
 * Lock the lock pointed to by p.  Spin (possibly forever) until the next
 * lock is available.
 */
	TEXT

#ifndef KERNEL
LEAF(_ev_lock, 0)
LEAF(_IOSpinLock, 0)
	movl		4(%esp), %ecx
0:
	xorl		%eax, %eax
	rep
	nop		/* pause for hyperthreaded CPU's */
	lock
	cmpxchgl	%ecx, (%ecx)
	jne		0b
	ret
END(_ev_lock)
#endif

/*
 * void
 * ev_unlock(p)
 *	int *p;
 *
 * Unlock the lock pointed to by p.
 */
LEAF(_ev_unlock, 0)
LEAF(_IOSpinUnlock, 0)
	movl		4(%esp), %ecx
	movl		$0, (%ecx)
	ENABLE_PREEMPTION()
	ret
END(_ev_unlock)


/*
 * int
 * ev_try_lock(p)
 *	int *p;
 *
 * Try to lock p.  Return zero if not successful.
 */

LEAF(_ev_try_lock, 0)
LEAF(_IOTrySpinLock, 0)
        DISABLE_PREEMPTION()
        movl            4(%esp), %ecx 
	xorl		%eax, %eax
        lock
        cmpxchgl        %ecx, (%ecx)
	jne	1f
	movl	$1, %eax		/* yes */
	ret
1:
	ENABLE_PREEMPTION()
	xorl	%eax, %eax		/* no */
END(_ev_try_lock)


#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
43866e37	6	* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
1c79356b	7	*
43866e37 A	8	* This file contains Original Code and/or Modifications of Original Code
	9	* as defined in and that are subject to the Apple Public Source License
	10	* Version 2.0 (the 'License'). You may not use this file except in
	11	* compliance with the License. Please obtain a copy of the License at
	12	* http://www.opensource.apple.com/apsl/ and read it before using this
	13	* file.
	14	*
	15	* The Original Code and all software distributed under the License are
	16	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	17	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	18	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
43866e37 A	19	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	20	* Please see the License for the specific language governing rights and
	21	* limitations under the License.
1c79356b A	22	*
	23	* @APPLE_LICENSE_HEADER_END@
	24	*/
	25	/*
	26	* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	27	*
	28	* HISTORY
	29	*
	30	*/
	31
	32	/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved.
	33	*
	34	* EventShmemLock.h - Shared memory area locks for use between the
	35	* WindowServer and the Event Driver.
	36	*
	37	*
	38	* HISTORY
	39	* 29 April 1992 Mike Paquette at NeXT
	40	* Created.
	41	*
	42	* Multiprocessor locks used within the shared memory area between the
	43	* kernel and event system. These must work in both user and kernel mode.
	44	* The locks are defined in an include file so they get exported to the local
	45	* include file area.
	46	*
	47	* This is basically a ripoff of the spin locks under the cthreads packages.
	48	*/
	49
	50	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	51	#define _IOKIT_IOSHAREDLOCKIMP_H
	52
	53	#include <architecture/i386/asm_help.h>
	54
	55	// 'Till we're building in kernel
	56	.macro DISABLE_PREEMPTION
	57	#ifdef KERNEL
	58	#endif
	59	.endmacro
	60	.macro ENABLE_PREEMPTION
	61	#ifdef KERNEL
	62	#endif
	63	.endmacro
	64
	65	/*
	66	* void
	67	* ev_lock(p)
	68	* int *p;
	69	*
	70	* Lock the lock pointed to by p. Spin (possibly forever) until the next
	71	* lock is available.
	72	*/
	73	TEXT
	74
	75	#ifndef KERNEL
	76	LEAF(_ev_lock, 0)
	77	LEAF(_IOSpinLock, 0)
55e303ae A	78	movl 4(%esp), %ecx
	79	0:
	80	xorl %eax, %eax
	81	rep
	82	nop /* pause for hyperthreaded CPU's */
	83	lock
	84	cmpxchgl %ecx, (%ecx)
	85	jne 0b
	86	ret
1c79356b A	87	END(_ev_lock)
	88	#endif
	89
	90	/*
	91	* void
	92	* ev_unlock(p)
	93	* int *p;
	94	*
	95	* Unlock the lock pointed to by p.
	96	*/
	97	LEAF(_ev_unlock, 0)
	98	LEAF(_IOSpinUnlock, 0)
55e303ae A	99	movl 4(%esp), %ecx
55e303ae A	100	movl $0, (%ecx)
1c79356b	101	ENABLE_PREEMPTION()
55e303ae	102	ret
1c79356b A	103	END(_ev_unlock)
	104
	105
	106
	107	/*
	108	* int
	109	* ev_try_lock(p)
	110	* int *p;
	111	*
	112	* Try to lock p. Return zero if not successful.
	113	*/
	114
	115	LEAF(_ev_try_lock, 0)
	116	LEAF(_IOTrySpinLock, 0)
	117	DISABLE_PREEMPTION()
55e303ae A	118	movl 4(%esp), %ecx
	119	xorl %eax, %eax
	120	lock
	121	cmpxchgl %ecx, (%ecx)
	122	jne 1f
1c79356b A	123	movl $1, %eax /* yes */
	124	ret
	125	1:
	126	ENABLE_PREEMPTION()
	127	xorl %eax, %eax /* no */
	128	END(_ev_try_lock)
	129
	130
	131	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */