atomic.h revision 51917 
1/*-
2 * Copyright (c) 1998 Doug Rabson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/i386/include/atomic.h 51917 1999-10-03 21:15:25Z eivind $
27 */
28#ifndef _MACHINE_ATOMIC_H_
29#define _MACHINE_ATOMIC_H_
30
31/*
32 * Various simple arithmetic on memory which is atomic in the presence
33 * of interrupts and multiple processors.
34 *
35 * atomic_set_char(P, V)	(*(u_char*)(P) |= (V))
36 * atomic_clear_char(P, V)	(*(u_char*)(P) &= ~(V))
37 * atomic_add_char(P, V)	(*(u_char*)(P) += (V))
38 * atomic_subtract_char(P, V)	(*(u_char*)(P) -= (V))
39 *
40 * atomic_set_short(P, V)	(*(u_short*)(P) |= (V))
41 * atomic_clear_short(P, V)	(*(u_short*)(P) &= ~(V))
42 * atomic_add_short(P, V)	(*(u_short*)(P) += (V))
43 * atomic_subtract_short(P, V)	(*(u_short*)(P) -= (V))
44 *
45 * atomic_set_int(P, V)		(*(u_int*)(P) |= (V))
46 * atomic_clear_int(P, V)	(*(u_int*)(P) &= ~(V))
47 * atomic_add_int(P, V)		(*(u_int*)(P) += (V))
48 * atomic_subtract_int(P, V)	(*(u_int*)(P) -= (V))
49 *
50 * atomic_set_long(P, V)	(*(u_long*)(P) |= (V))
51 * atomic_clear_long(P, V)	(*(u_long*)(P) &= ~(V))
52 * atomic_add_long(P, V)	(*(u_long*)(P) += (V))
53 * atomic_subtract_long(P, V)	(*(u_long*)(P) -= (V))
54 */
55
56/*
57 * The above functions are expanded inline in the statically-linked
58 * kernel.  Lock prefixes are generated if an SMP kernel is being
59 * built.
60 *
61 * Kernel modules call real functions which are built into the kernel.
62 * This allows kernel modules to be portable between UP and SMP systems.
63 */
64#if defined(KLD_MODULE)
65#define ATOMIC_ASM(NAME, TYPE, OP, V)			\
66	extern void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v);
67
68#else /* !KLD_MODULE */
69#if defined(SMP)
70#define MPLOCKED	"lock ; "
71#else
72#define MPLOCKED
73#endif
74
75/*
76 * The assembly is volatilized to demark potential before-and-after side
77 * effects if an interrupt or SMP collision were to occur.
78 */
79#define ATOMIC_ASM(NAME, TYPE, OP, V)			\
80static __inline void					\
81atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
82{							\
83	__asm __volatile(MPLOCKED OP			\
84			 : "=m" (*p)			\
85			 :  "0" (*p), "ir" (V)); 	\
86}
87#endif /* KLD_MODULE */
88
89#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR_ > 9)
90ATOMIC_ASM(set,	     char,  "orb %2,%0",   v)
91ATOMIC_ASM(clear,    char,  "andb %2,%0", ~v)
92ATOMIC_ASM(add,	     char,  "addb %2,%0",  v)
93ATOMIC_ASM(subtract, char,  "subb %2,%0",  v)
94
95ATOMIC_ASM(set,	     short, "orw %2,%0",   v)
96ATOMIC_ASM(clear,    short, "andw %2,%0", ~v)
97ATOMIC_ASM(add,	     short, "addw %2,%0",  v)
98ATOMIC_ASM(subtract, short, "subw %2,%0",  v)
99
100ATOMIC_ASM(set,	     int,   "orl %2,%0",   v)
101ATOMIC_ASM(clear,    int,   "andl %2,%0", ~v)
102ATOMIC_ASM(add,	     int,   "addl %2,%0",  v)
103ATOMIC_ASM(subtract, int,   "subl %2,%0",  v)
104
105ATOMIC_ASM(set,	     long,  "orl %2,%0",   v)
106ATOMIC_ASM(clear,    long,  "andl %2,%0", ~v)
107ATOMIC_ASM(add,	     long,  "addl %2,%0",  v)
108ATOMIC_ASM(subtract, long,  "subl %2,%0",  v)
109
110#else
111#define atomic_set_char(P, V)		(*(u_char*)(P) |= (V))
112#define atomic_clear_char(P, V)		(*(u_char*)(P) &= ~(V))
113#define atomic_add_char(P, V)		(*(u_char*)(P) += (V))
114#define atomic_subtract_char(P, V)	(*(u_char*)(P) -= (V))
115
116#define atomic_set_short(P, V)		(*(u_short*)(P) |= (V))
117#define atomic_clear_short(P, V)	(*(u_short*)(P) &= ~(V))
118#define atomic_add_short(P, V)		(*(u_short*)(P) += (V))
119#define atomic_subtract_short(P, V)	(*(u_short*)(P) -= (V))
120
121#define atomic_set_int(P, V)		(*(u_int*)(P) |= (V))
122#define atomic_clear_int(P, V)		(*(u_int*)(P) &= ~(V))
123#define atomic_add_int(P, V)		(*(u_int*)(P) += (V))
124#define atomic_subtract_int(P, V)	(*(u_int*)(P) -= (V))
125
126#define atomic_set_long(P, V)		(*(u_long*)(P) |= (V))
127#define atomic_clear_long(P, V)		(*(u_long*)(P) &= ~(V))
128#define atomic_add_long(P, V)		(*(u_long*)(P) += (V))
129#define atomic_subtract_long(P, V)	(*(u_long*)(P) -= (V))
130#endif
131
132#endif /* ! _MACHINE_ATOMIC_H_ */
133