atomic.h revision 65514
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 65514 2000-09-06 11:21:14Z phk $ 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 68extern int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src); 69 70#else /* !KLD_MODULE */ 71#if defined(SMP) 72#if defined(LOCORE) 73#define MPLOCKED lock ; 74#else 75#define MPLOCKED "lock ; " 76#endif 77#else 78#define MPLOCKED 79#endif 80 81/* 82 * The assembly is volatilized to demark potential before-and-after side 83 * effects if an interrupt or SMP collision were to occur. 84 */ 85#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 9) 86/* egcs 1.1.2+ version */ 87#define ATOMIC_ASM(NAME, TYPE, OP, V) \ 88static __inline void \ 89atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 90{ \ 91 __asm __volatile(MPLOCKED OP \ 92 : "=m" (*p) \ 93 : "0" (*p), "ir" (V)); \ 94} 95 96/* 97 * Atomic compare and set, used by the mutex functions 98 * 99 * if (*dst == exp) *dst = src (all 32 bit words) 100 * 101 * Returns 0 on failure, non-zero on success 102 */ 103 104#if defined(I386_CPU) 105static __inline int 106atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 107{ 108 int res = exp; 109 110 __asm __volatile( 111 " pushfl ; " 112 " cli ; " 113 " cmpl %1,%3 ; " 114 " jne 1f ; " 115 " movl %2,%3 ; " 116 "1: " 117 " sete %%al; " 118 " movzbl %%al,%0 ; " 119 " popfl ; " 120 "# atomic_cmpset_int" 121 : "=a" (res) /* 0 (result) */ 122 : "0" (exp), /* 1 */ 123 "r" (src), /* 2 */ 124 "m" (*(dst)) /* 3 */ 125 : "memory"); 126 127 return (res); 128} 129#else /* defined(I386_CPU) */ 130static __inline int 131atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 132{ 133 int res = exp; 134 135 __asm __volatile ( 136 " " MPLOCKED " " 137 " cmpxchgl %2,%3 ; " 138 " setz %%al ; " 139 " movzbl %%al,%0 ; " 140 "1: " 141 "# atomic_cmpset_int" 142 : "=a" (res) /* 0 (result) */ 143 : "0" (exp), /* 1 */ 144 "r" (src), /* 2 */ 145 "m" (*(dst)) /* 3 */ 146 : "memory"); 147 148 return (res); 149} 150#endif /* defined(I386_CPU) */ 151 152#else 153/* gcc <= 2.8 version */ 154#define ATOMIC_ASM(NAME, TYPE, OP, V) \ 155static __inline void \ 156atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 157{ \ 158 __asm __volatile(MPLOCKED OP \ 159 : "=m" (*p) \ 160 : "ir" (V)); \ 161} 162#endif 163#endif /* KLD_MODULE */ 164 165#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 9) 166 167/* egcs 1.1.2+ version */ 168ATOMIC_ASM(set, char, "orb %b2,%0", v) 169ATOMIC_ASM(clear, char, "andb %b2,%0", ~v) 170ATOMIC_ASM(add, char, "addb %b2,%0", v) 171ATOMIC_ASM(subtract, char, "subb %b2,%0", v) 172 173ATOMIC_ASM(set, short, "orw %w2,%0", v) 174ATOMIC_ASM(clear, short, "andw %w2,%0", ~v) 175ATOMIC_ASM(add, short, "addw %w2,%0", v) 176ATOMIC_ASM(subtract, short, "subw %w2,%0", v) 177 178ATOMIC_ASM(set, int, "orl %2,%0", v) 179ATOMIC_ASM(clear, int, "andl %2,%0", ~v) 180ATOMIC_ASM(add, int, "addl %2,%0", v) 181ATOMIC_ASM(subtract, int, "subl %2,%0", v) 182 183ATOMIC_ASM(set, long, "orl %2,%0", v) 184ATOMIC_ASM(clear, long, "andl %2,%0", ~v) 185ATOMIC_ASM(add, long, "addl %2,%0", v) 186ATOMIC_ASM(subtract, long, "subl %2,%0", v) 187 188#else 189 190/* gcc <= 2.8 version */ 191ATOMIC_ASM(set, char, "orb %1,%0", v) 192ATOMIC_ASM(clear, char, "andb %1,%0", ~v) 193ATOMIC_ASM(add, char, "addb %1,%0", v) 194ATOMIC_ASM(subtract, char, "subb %1,%0", v) 195 196ATOMIC_ASM(set, short, "orw %1,%0", v) 197ATOMIC_ASM(clear, short, "andw %1,%0", ~v) 198ATOMIC_ASM(add, short, "addw %1,%0", v) 199ATOMIC_ASM(subtract, short, "subw %1,%0", v) 200 201ATOMIC_ASM(set, int, "orl %1,%0", v) 202ATOMIC_ASM(clear, int, "andl %1,%0", ~v) 203ATOMIC_ASM(add, int, "addl %1,%0", v) 204ATOMIC_ASM(subtract, int, "subl %1,%0", v) 205 206ATOMIC_ASM(set, long, "orl %1,%0", v) 207ATOMIC_ASM(clear, long, "andl %1,%0", ~v) 208ATOMIC_ASM(add, long, "addl %1,%0", v) 209ATOMIC_ASM(subtract, long, "subl %1,%0", v) 210 211#endif 212 213#ifndef WANT_FUNCTIONS 214static __inline int 215atomic_cmpset_ptr(volatile void *dst, void *exp, void *src) 216{ 217 218 return ( 219 atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, (u_int)src)); 220} 221#endif 222 223#endif /* ! _MACHINE_ATOMIC_H_ */ 224