2 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. Berkeley Software Design Inc's name may not be used to endorse or
13 * promote products derived from this software without specific prior
16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
32 #ifndef _MACHINE_MUTEX_H_
33 #define _MACHINE_MUTEX_H_
39 * Simple assembly macros to get and release non-recursive spin locks
41 #define MTX_ENTER(lck) \
42 mfmsr r10; \ /* disable interrupts */
43 rlwinm r0, r10, 0, 17, 15; \
45 1: li r11, MTX_LOCK; \ /* MTX_LOCK offset */
46 lwarx r0, r11, lck; \ /* load current lock value */
47 cmplwi r0, r1, MTX_UNOWNED; \ /* compare with unowned */
48 beq 1; \ /* if owned, loop */
49 lwz r0, PC_CURPROC(pcpup); \ /* load curproc */
50 stwcx. r0, r11, lck; \ /* attempt to store */
51 beq 1; \ /* loop if failed */
54 stw r10, MTX_SAVEINTR(lck) /* save flags */
56 #define MTX_EXIT(lck) \
59 li r0, MTX_UNOWNED; \ /* load in unowned */
60 stw r0, MTX_LOCK(lck); \ /* store to lock */
61 lwz r0, MTX_SAVEINTR(lck); \ /* load saved flags */
62 mtmsr r0 /* enable interrupts */
67 #endif /* __MACHINE_MUTEX_H */