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 * $FreeBSD$
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 * Warning: Use this version with gcc 2.7.2.x only. Newer compilers
65 * require different constraints in the asm statement.
66 */
67 #if defined(KLD_MODULE)
68 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
69 extern void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v);
70
71 #else /* !KLD_MODULE */
72 #if defined(SMP)
73 #define MPLOCKED "lock ; "
74 #else
75 #define MPLOCKED
76 #endif
77
78 /*
79 * The assembly is volatilized to demark potential before-and-after side
80 * effects if an interrupt or SMP collision were to occur.
81 */
82 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
83 static __inline void \
84 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
85 { \
86 __asm __volatile(MPLOCKED OP \
87 : "=m" (*p) \
88 : CONS (V)); \
89 }
90 #endif /* KLD_MODULE */
91
92 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v)
93 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v)
94 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v)
95 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v)
96
97 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v)
98 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v)
99 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v)
100 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v)
101
102 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v)
103 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v)
104 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v)
105 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v)
106
107 ATOMIC_ASM(set, long, "orl %1,%0", "ir", v)
108 ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v)
109 ATOMIC_ASM(add, long, "addl %1,%0", "ir", v)
110 ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v)
111
112 #endif /* ! _MACHINE_ATOMIC_H_ */
Cache object: 18e626d79bc66d9eafe98cf25824b245
|