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 * atomic_readandclear_int(P) (return *(u_int*)P; *(u_int*)P = 0;)
50 *
51 * atomic_set_long(P, V) (*(u_long*)(P) |= (V))
52 * atomic_clear_long(P, V) (*(u_long*)(P) &= ~(V))
53 * atomic_add_long(P, V) (*(u_long*)(P) += (V))
54 * atomic_subtract_long(P, V) (*(u_long*)(P) -= (V))
55 * atomic_readandclear_long(P) (return *(u_long*)P; *(u_long*)P = 0;)
56 */
57
58 /*
59 * The above functions are expanded inline in the statically-linked
60 * kernel. Lock prefixes are generated if an SMP kernel is being
61 * built.
62 *
63 * Kernel modules call real functions which are built into the kernel.
64 * This allows kernel modules to be portable between UP and SMP systems.
65 */
66 #if defined(KLD_MODULE)
67 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
68 void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
69
70 #else /* !KLD_MODULE */
71 #if defined(SMP)
72 #define MPLOCKED "lock ; "
73 #else
74 #define MPLOCKED
75 #endif
76
77 /*
78 * The assembly is volatilized to demark potential before-and-after side
79 * effects if an interrupt or SMP collision were to occur.
80 */
81 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
82 static __inline void \
83 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
84 { \
85 __asm __volatile(MPLOCKED OP \
86 : "=m" (*p) \
87 : CONS (V), "m" (*p)); \
88 } \
89 struct __hack
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 #define atomic_readandclear_32 atomic_readandclear_int
113
114 #ifndef WANT_FUNCTIONS
115 static __inline u_int
116 atomic_readandclear_int(volatile u_int *addr)
117 {
118 u_int result;
119
120 __asm __volatile (
121 " xorl %0,%0 ; "
122 " xchgl %1,%0 ; "
123 "# atomic_readandclear_int"
124 : "=&r" (result) /* 0 (result) */
125 : "m" (*addr)); /* 1 (addr) */
126
127 return (result);
128 }
129
130 static __inline u_long
131 atomic_readandclear_long(volatile u_long *addr)
132 {
133 u_long result;
134
135 __asm __volatile (
136 " xorl %0,%0 ; "
137 " xchgl %1,%0 ; "
138 "# atomic_readandclear_int"
139 : "=&r" (result) /* 0 (result) */
140 : "m" (*addr)); /* 1 (addr) */
141
142 return (result);
143 }
144 #endif
145
146 #endif /* ! _MACHINE_ATOMIC_H_ */
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