lock.h revision 1.5 
1/* $NetBSD: lock.h,v 1.5 2000/04/29 03:31:46 thorpej Exp $ */
2
3/*-
4 * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the NetBSD
22 *	Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 *    contributors may be used to endorse or promote products derived
25 *    from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40/*
41 * Machine-dependent spin lock operations.
42 */
43
44#ifndef _ALPHA_LOCK_H_
45#define	_ALPHA_LOCK_H_
46
47#define	__SIMPLELOCK_LOCKED	1
48#define	__SIMPLELOCK_UNLOCKED	0
49
50static __inline void __cpu_simple_lock_init __P((__volatile int *))
51	__attribute__((__unused__));
52static __inline void __cpu_simple_lock __P((__volatile int *))
53	__attribute__((__unused__));
54static __inline int __cpu_simple_lock_try __P((__volatile int *))
55	__attribute__((__unused__));
56static __inline void __cpu_simple_unlock __P((__volatile int *))
57	__attribute__((__unused__));
58
59static __inline void
60__cpu_simple_lock_init(__volatile int *alp)
61{
62
63	__asm __volatile(
64		"# BEGIN __cpu_simple_lock_init\n"
65		"	stl	$31, %0		\n"
66		"	mb			\n"
67		"	# END __cpu_simple_lock_init"
68		: "=m" (*alp));
69}
70
71static __inline void
72__cpu_simple_lock(__volatile int *alp)
73{
74	unsigned long t0;
75
76	/*
77	 * Note, if we detect that the lock is held when
78	 * we do the initial load-locked, we spin using
79	 * a non-locked load to save the coherency logic
80	 * some work.
81	 */
82
83	__asm __volatile(
84		"# BEGIN __cpu_simple_lock\n"
85		"1:	ldl_l	%0, %3		\n"
86		"	bne	%0, 2f		\n"
87		"	bis	$31, %2, %0	\n"
88		"	stl_c	%0, %1		\n"
89		"	beq	%0, 3f		\n"
90		"	mb			\n"
91		"	br	4f		\n"
92		"2:	ldl	%0, %3		\n"
93		"	beq	%0, 1b		\n"
94		"	br	2b		\n"
95		"3:	br	1b		\n"
96		"4:				\n"
97		"	# END __cpu_simple_lock\n"
98		: "=r" (t0), "=m" (*alp)
99		: "i" (__SIMPLELOCK_LOCKED), "1" (*alp));
100}
101
102static __inline int
103__cpu_simple_lock_try(__volatile int *alp)
104{
105	unsigned long t0, v0;
106
107	__asm __volatile(
108		"# BEGIN __cpu_simple_lock_try\n"
109		"1:	ldl_l	%0, %4		\n"
110		"	bne	%0, 2f		\n"
111		"	bis	$31, %3, %0	\n"
112		"	stl_c	%0, %2		\n"
113		"	beq	%0, 3f		\n"
114		"	mb			\n"
115		"	bis	$31, 1, %1	\n"
116		"	br	4f		\n"
117		"2:	bis	$31, $31, %1	\n"
118		"	br	4f		\n"
119		"3:	br	1b		\n"
120		"4:				\n"
121		"	# END __cpu_simple_lock_try"
122		: "=r" (t0), "=r" (v0), "=m" (*alp)
123		: "i" (__SIMPLELOCK_LOCKED), "2" (*alp));
124
125	return (v0);
126}
127
128static __inline void
129__cpu_simple_unlock(__volatile int *alp)
130{
131
132	__asm __volatile(
133		"# BEGIN __cpu_simple_unlock\n"
134		"	stl	$31, %0		\n"
135		"	mb			\n"
136		"	# END __cpu_simple_unlock"
137		: "=m" (*alp));
138}
139
140#endif /* _ALPHA_LOCK_H_ */
141