atomic.h revision 66695
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/amd64/include/atomic.h 66695 2000-10-05 22:19:50Z jhb $ 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, V) \ 68 void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v); 69 70int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src); 71 72#else /* !KLD_MODULE */ 73#if defined(SMP) 74#if defined(LOCORE) 75#define MPLOCKED lock ; 76#else 77#define MPLOCKED "lock ; " 78#endif 79#else 80#define MPLOCKED 81#endif 82 83/* 84 * The assembly is volatilized to demark potential before-and-after side 85 * effects if an interrupt or SMP collision were to occur. 86 */ 87#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 9) 88/* egcs 1.1.2+ version */ 89#define ATOMIC_ASM(NAME, TYPE, OP, V) \ 90static __inline void \ 91atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 92{ \ 93 __asm __volatile(MPLOCKED OP \ 94 : "=m" (*p) \ 95 : "0" (*p), "ir" (V)); \ 96} 97 98/* 99 * Atomic compare and set, used by the mutex functions 100 * 101 * if (*dst == exp) *dst = src (all 32 bit words) 102 * 103 * Returns 0 on failure, non-zero on success 104 */ 105 106#if defined(I386_CPU) 107static __inline int 108atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 109{ 110 int res = exp; 111 112 __asm __volatile( 113 " pushfl ; " 114 " cli ; " 115 " cmpl %1,%3 ; " 116 " jne 1f ; " 117 " movl %2,%3 ; " 118 "1: " 119 " sete %%al; " 120 " movzbl %%al,%0 ; " 121 " popfl ; " 122 "# atomic_cmpset_int" 123 : "=a" (res) /* 0 (result) */ 124 : "0" (exp), /* 1 */ 125 "r" (src), /* 2 */ 126 "m" (*(dst)) /* 3 */ 127 : "memory"); 128 129 return (res); 130} 131#else /* defined(I386_CPU) */ 132static __inline int 133atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 134{ 135 int res = exp; 136 137 __asm __volatile ( 138 " " MPLOCKED " " 139 " cmpxchgl %2,%3 ; " 140 " setz %%al ; " 141 " movzbl %%al,%0 ; " 142 "1: " 143 "# atomic_cmpset_int" 144 : "=a" (res) /* 0 (result) */ 145 : "0" (exp), /* 1 */ 146 "r" (src), /* 2 */ 147 "m" (*(dst)) /* 3 */ 148 : "memory"); 149 150 return (res); 151} 152#endif /* defined(I386_CPU) */ 153 154#else 155/* gcc <= 2.8 version */ 156#define ATOMIC_ASM(NAME, TYPE, OP, V) \ 157static __inline void \ 158atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 159{ \ 160 __asm __volatile(MPLOCKED OP \ 161 : "=m" (*p) \ 162 : "ir" (V)); \ 163} 164#endif 165#endif /* KLD_MODULE */ 166 167#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 9) 168 169/* egcs 1.1.2+ version */ 170ATOMIC_ASM(set, char, "orb %b2,%0", v) 171ATOMIC_ASM(clear, char, "andb %b2,%0", ~v) 172ATOMIC_ASM(add, char, "addb %b2,%0", v) 173ATOMIC_ASM(subtract, char, "subb %b2,%0", v) 174 175ATOMIC_ASM(set, short, "orw %w2,%0", v) 176ATOMIC_ASM(clear, short, "andw %w2,%0", ~v) 177ATOMIC_ASM(add, short, "addw %w2,%0", v) 178ATOMIC_ASM(subtract, short, "subw %w2,%0", v) 179 180ATOMIC_ASM(set, int, "orl %2,%0", v) 181ATOMIC_ASM(clear, int, "andl %2,%0", ~v) 182ATOMIC_ASM(add, int, "addl %2,%0", v) 183ATOMIC_ASM(subtract, int, "subl %2,%0", v) 184 185ATOMIC_ASM(set, long, "orl %2,%0", v) 186ATOMIC_ASM(clear, long, "andl %2,%0", ~v) 187ATOMIC_ASM(add, long, "addl %2,%0", v) 188ATOMIC_ASM(subtract, long, "subl %2,%0", v) 189 190#else 191 192/* gcc <= 2.8 version */ 193ATOMIC_ASM(set, char, "orb %1,%0", v) 194ATOMIC_ASM(clear, char, "andb %1,%0", ~v) 195ATOMIC_ASM(add, char, "addb %1,%0", v) 196ATOMIC_ASM(subtract, char, "subb %1,%0", v) 197 198ATOMIC_ASM(set, short, "orw %1,%0", v) 199ATOMIC_ASM(clear, short, "andw %1,%0", ~v) 200ATOMIC_ASM(add, short, "addw %1,%0", v) 201ATOMIC_ASM(subtract, short, "subw %1,%0", v) 202 203ATOMIC_ASM(set, int, "orl %1,%0", v) 204ATOMIC_ASM(clear, int, "andl %1,%0", ~v) 205ATOMIC_ASM(add, int, "addl %1,%0", v) 206ATOMIC_ASM(subtract, int, "subl %1,%0", v) 207 208ATOMIC_ASM(set, long, "orl %1,%0", v) 209ATOMIC_ASM(clear, long, "andl %1,%0", ~v) 210ATOMIC_ASM(add, long, "addl %1,%0", v) 211ATOMIC_ASM(subtract, long, "subl %1,%0", v) 212 213#endif 214 215#ifndef WANT_FUNCTIONS 216static __inline int 217atomic_cmpset_ptr(volatile void *dst, void *exp, void *src) 218{ 219 220 return ( 221 atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, (u_int)src)); 222} 223 224static __inline u_int 225atomic_readandclear_int(volatile u_int *addr) 226{ 227 u_int result; 228 229 __asm __volatile ( 230 " xorl %0,%0 ; " 231 " xchgl %1,%0 ; " 232 "# atomic_readandclear_int" 233 : "=&r" (result) /* 0 (result) */ 234 : "m" (*addr)); /* 1 (addr) */ 235 236 return (result); 237} 238 239static __inline u_long 240atomic_readandclear_long(volatile u_long *addr) 241{ 242 u_long result; 243 244 __asm __volatile ( 245 " xorl %0,%0 ; " 246 " xchgl %1,%0 ; " 247 "# atomic_readandclear_int" 248 : "=&r" (result) /* 0 (result) */ 249 : "m" (*addr)); /* 1 (addr) */ 250 251 return (result); 252} 253#endif 254 255#endif /* ! _MACHINE_ATOMIC_H_ */ 256