[apple/xnu.git] / iokit / IOKit / ppc / 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
 * 30 Nov   1992    Ben Fathi (benf@next.com)
 *      Ported to m98k.
 *
 * 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.
 */


#ifndef _IOKIT_IOSHAREDLOCKIMP_H
#define _IOKIT_IOSHAREDLOCKIMP_H

#include <architecture/ppc/asm_help.h>
#ifdef KERNEL
#undef END
#include <mach/ppc/asm.h>
#endif

.macro DISABLE_PREEMPTION
#ifdef KERNEL
	stwu	r1,-(FM_SIZE)(r1)
	mflr	r0
	stw		r3,FM_ARG0(r1)
	stw		r0,(FM_SIZE+FM_LR_SAVE)(r1)
	bl		EXT(_disable_preemption)
	lwz		r3,FM_ARG0(r1)
	lwz		r1,0(r1)
	lwz		r0,FM_LR_SAVE(r1)
	mtlr	r0
#endif
.endmacro
.macro ENABLE_PREEMPTION
#ifdef KERNEL
	stwu	r1,-(FM_SIZE)(r1)
	mflr	r0
	stw		r3,FM_ARG0(r1)
	stw		r0,(FM_SIZE+FM_LR_SAVE)(r1)
	bl		EXT(_enable_preemption)
	lwz		r3,FM_ARG0(r1)
	lwz		r1,0(r1)
	lwz		r0,FM_LR_SAVE(r1)
	mtlr	r0
#endif
.endmacro

/*
 *	void
 *	ev_lock(p)
 *		register int *p;
 *
 *	Lock the lock pointed to by p.  Spin (possibly forever) until
 *		the lock is available.  Test and test and set logic used.
 */
	TEXT

#ifndef KERNEL
LEAF(_ev_lock)

		li		a6,1			// lock value
		
8:		lwz		a7,0(a0)		// Get lock word
		mr.		a7,a7			// Is it held?
		bne--	8b				// Yup...

9:		lwarx	a7,0,a0			// read the lock
		mr.		a7,a7			// Is it held?
		bne--	7f				// yes, kill reservation
		stwcx.	a6,0,a0			// try to get the lock
		bne--	9b 				// failed, try again
		isync
		blr						// got it, return
		
7:		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation
		b		8b				// Go wait some more...
		
		
END(_ev_lock)

LEAF(_IOSpinLock)

		li		a6,1			// lock value
		
8:		lwz		a7,0(a0)		// Get lock word
		mr.		a7,a7			// Is it held?
		bne--	8b				// Yup...

9:		lwarx	a7,0,a0			// read the lock
		mr.		a7,a7			// Is it held?
		bne--	7f				// yes, kill reservation
		stwcx.	a6,0,a0			// try to get the lock
		bne--	9b 				// failed, try again
		isync
		blr						// got it, return
		
7:		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation
		b		8b				// Go wait some more...
END(_IOSpinLock)
#endif

/*
 *	void
 *	spin_unlock(p)
 *		int *p;
 *
 *	Unlock the lock pointed to by p.
 */

LEAF(_ev_unlock)
	sync
	li	a7,0
	stw	a7,0(a0)
	ENABLE_PREEMPTION()
	blr
END(_ev_unlock)

LEAF(_IOSpinUnlock)
	sync
	li	a7,0
	stw	a7,0(a0)
	ENABLE_PREEMPTION()
	blr
END(_IOSpinUnlock)


/*
 *	ev_try_lock(p)
 *		int *p;
 *
 *	Try to lock p.  Return TRUE if successful in obtaining lock.
 */

LEAF(_ev_try_lock)
	
		DISABLE_PREEMPTION()

		li		a6,1			// lock value
		
		lwz		a7,0(a0)		// Get lock word
		mr.		a7,a7			// Is it held?
		bne--	6f				// Yup...

9:		lwarx	a7,0,a0			// read the lock
		mr.		a7,a7			// Is it held?
		bne--	7f				// yes, kill reservation
		stwcx.	a6,0,a0			// try to get the lock
		bne--	9b 				// failed, try again
		li		a0,1			// return TRUE
		isync
		blr						// got it, return
		
7:		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation

6:
		ENABLE_PREEMPTION()
		li	a0,0				// return FALSE
		blr
		
END(_ev_try_lock)

LEAF(_IOTrySpinLock)
	
		DISABLE_PREEMPTION()

		li		a6,1			// lock value
		
		lwz		a7,0(a0)		// Get lock word
		mr.		a7,a7			// Is it held?
		bne--	6f				// Yup...

9:		lwarx	a7,0,a0			// read the lock
		mr.		a7,a7			// Is it held?
		bne--	7f				// yes, kill reservation
		stwcx.	a6,0,a0			// try to get the lock
		bne--	9b 				// failed, try again
		li		a0,1			// return TRUE
		isync
		blr						// got it, return
		
7:		li		a7,-4			// Point to a spot in the red zone
		stwcx.	a7,a7,r1		// Kill reservation

6:
		ENABLE_PREEMPTION()
		li	a0,0				// return FALSE
		blr
		
END(_IOTrySpinLock)

#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	* HISTORY
	38	* 30 Nov 1992 Ben Fathi (benf@next.com)
	39	* Ported to m98k.
	40	*
	41	* 29 April 1992 Mike Paquette at NeXT
	42	* Created.
	43	*
	44	* Multiprocessor locks used within the shared memory area between the
	45	* kernel and event system. These must work in both user and kernel mode.
	46	* The locks are defined in an include file so they get exported to the local
	47	* include file area.
	48	*/
	49
	50
	51	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	52	#define _IOKIT_IOSHAREDLOCKIMP_H
	53
	54	#include <architecture/ppc/asm_help.h>
7b1edb79 A	55	#ifdef KERNEL
	56	#undef END
	57	#include <mach/ppc/asm.h>
	58	#endif
1c79356b	59
1c79356b A	60	.macro DISABLE_PREEMPTION
1c79356b A	61	#ifdef KERNEL
7b1edb79 A	62	stwu r1,-(FM_SIZE)(r1)
	63	mflr r0
	64	stw r3,FM_ARG0(r1)
	65	stw r0,(FM_SIZE+FM_LR_SAVE)(r1)
	66	bl EXT(_disable_preemption)
	67	lwz r3,FM_ARG0(r1)
	68	lwz r1,0(r1)
	69	lwz r0,FM_LR_SAVE(r1)
	70	mtlr r0
1c79356b A	71	#endif
	72	.endmacro
	73	.macro ENABLE_PREEMPTION
	74	#ifdef KERNEL
7b1edb79 A	75	stwu r1,-(FM_SIZE)(r1)
	76	mflr r0
	77	stw r3,FM_ARG0(r1)
	78	stw r0,(FM_SIZE+FM_LR_SAVE)(r1)
	79	bl EXT(_enable_preemption)
	80	lwz r3,FM_ARG0(r1)
	81	lwz r1,0(r1)
	82	lwz r0,FM_LR_SAVE(r1)
	83	mtlr r0
1c79356b A	84	#endif
	85	.endmacro
	86
	87	/*
	88	* void
	89	* ev_lock(p)
	90	* register int *p;
	91	*
	92	* Lock the lock pointed to by p. Spin (possibly forever) until
	93	* the lock is available. Test and test and set logic used.
	94	*/
	95	TEXT
	96
	97	#ifndef KERNEL
	98	LEAF(_ev_lock)
55e303ae A	99
	100	li a6,1 // lock value
	101
	102	8: lwz a7,0(a0) // Get lock word
	103	mr. a7,a7 // Is it held?
	104	bne-- 8b // Yup...
	105
	106	9: lwarx a7,0,a0 // read the lock
	107	mr. a7,a7 // Is it held?
	108	bne-- 7f // yes, kill reservation
	109	stwcx. a6,0,a0 // try to get the lock
	110	bne-- 9b // failed, try again
	111	isync
	112	blr // got it, return
	113
	114	7: li a7,-4 // Point to a spot in the red zone
	115	stwcx. a7,a7,r1 // Kill reservation
	116	b 8b // Go wait some more...
	117
	118
1c79356b	119	END(_ev_lock)
0b4e3aa0 A	120
0b4e3aa0 A	121	LEAF(_IOSpinLock)
55e303ae A	122
	123	li a6,1 // lock value
	124
	125	8: lwz a7,0(a0) // Get lock word
	126	mr. a7,a7 // Is it held?
	127	bne-- 8b // Yup...
	128
	129	9: lwarx a7,0,a0 // read the lock
	130	mr. a7,a7 // Is it held?
	131	bne-- 7f // yes, kill reservation
	132	stwcx. a6,0,a0 // try to get the lock
	133	bne-- 9b // failed, try again
	134	isync
	135	blr // got it, return
	136
	137	7: li a7,-4 // Point to a spot in the red zone
	138	stwcx. a7,a7,r1 // Kill reservation
	139	b 8b // Go wait some more...
0b4e3aa0	140	END(_IOSpinLock)
1c79356b A	141	#endif
	142
	143	/*
	144	* void
	145	* spin_unlock(p)
	146	* int *p;
	147	*
	148	* Unlock the lock pointed to by p.
	149	*/
	150
	151	LEAF(_ev_unlock)
1c79356b A	152	sync
	153	li a7,0
	154	stw a7,0(a0)
	155	ENABLE_PREEMPTION()
	156	blr
	157	END(_ev_unlock)
	158
0b4e3aa0 A	159	LEAF(_IOSpinUnlock)
	160	sync
	161	li a7,0
	162	stw a7,0(a0)
	163	ENABLE_PREEMPTION()
	164	blr
	165	END(_IOSpinUnlock)
	166
1c79356b A	167
	168	/*
	169	* ev_try_lock(p)
	170	* int *p;
	171	*
	172	* Try to lock p. Return TRUE if successful in obtaining lock.
	173	*/
	174
	175	LEAF(_ev_try_lock)
55e303ae A	176
	177	DISABLE_PREEMPTION()
	178
	179	li a6,1 // lock value
	180
	181	lwz a7,0(a0) // Get lock word
	182	mr. a7,a7 // Is it held?
	183	bne-- 6f // Yup...
	184
	185	9: lwarx a7,0,a0 // read the lock
	186	mr. a7,a7 // Is it held?
	187	bne-- 7f // yes, kill reservation
	188	stwcx. a6,0,a0 // try to get the lock
	189	bne-- 9b // failed, try again
	190	li a0,1 // return TRUE
	191	isync
	192	blr // got it, return
	193
	194	7: li a7,-4 // Point to a spot in the red zone
	195	stwcx. a7,a7,r1 // Kill reservation
	196
	197	6:
	198	ENABLE_PREEMPTION()
	199	li a0,0 // return FALSE
	200	blr
	201
1c79356b A	202	END(_ev_try_lock)
1c79356b A	203
0b4e3aa0	204	LEAF(_IOTrySpinLock)
55e303ae A	205
	206	DISABLE_PREEMPTION()
	207
	208	li a6,1 // lock value
	209
	210	lwz a7,0(a0) // Get lock word
	211	mr. a7,a7 // Is it held?
	212	bne-- 6f // Yup...
	213
	214	9: lwarx a7,0,a0 // read the lock
	215	mr. a7,a7 // Is it held?
	216	bne-- 7f // yes, kill reservation
	217	stwcx. a6,0,a0 // try to get the lock
	218	bne-- 9b // failed, try again
	219	li a0,1 // return TRUE
	220	isync
	221	blr // got it, return
	222
	223	7: li a7,-4 // Point to a spot in the red zone
	224	stwcx. a7,a7,r1 // Kill reservation
	225
	226	6:
	227	ENABLE_PREEMPTION()
	228	li a0,0 // return FALSE
	229	blr
	230
0b4e3aa0 A	231	END(_IOTrySpinLock)
0b4e3aa0 A	232
1c79356b	233	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */