atomic.h revision 72358
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 72358 2001-02-11 10:44:09Z markm $ 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) \ 68void 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#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 73u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 74void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v); 75 76#else /* !KLD_MODULE */ 77 78#if defined(SMP) 79#if defined(LOCORE) 80#define MPLOCKED lock ; 81#else /* !LOCORE */ 82#define MPLOCKED "lock ; " 83#endif /* LOCORE */ 84#else /* !SMP */ 85#define MPLOCKED 86#endif /* SMP */ 87 88#if !defined(LOCORE) 89/* 90 * The assembly is volatilized to demark potential before-and-after side 91 * effects if an interrupt or SMP collision were to occur. 92 */ 93#define ATOMIC_ASM(NAME, TYPE, OP, V) \ 94static __inline void \ 95atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 96{ \ 97 __asm __volatile(MPLOCKED OP \ 98 : "=m" (*p) \ 99 : "0" (*p), "ir" (V)); \ 100} 101 102/* 103 * Atomic compare and set, used by the mutex functions 104 * 105 * if (*dst == exp) *dst = src (all 32 bit words) 106 * 107 * Returns 0 on failure, non-zero on success 108 */ 109 110#if defined(I386_CPU) 111static __inline int 112atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 113{ 114 int res = exp; 115 116 __asm __volatile( 117 " pushfl ; " 118 " cli ; " 119 " cmpl %1,%3 ; " 120 " jne 1f ; " 121 " movl %2,%3 ; " 122 "1: " 123 " sete %%al; " 124 " movzbl %%al,%0 ; " 125 " popfl ; " 126 "# atomic_cmpset_int" 127 : "=a" (res) /* 0 (result) */ 128 : "0" (exp), /* 1 */ 129 "r" (src), /* 2 */ 130 "m" (*(dst)) /* 3 */ 131 : "memory"); 132 133 return (res); 134} 135#else /* defined(I386_CPU) */ 136static __inline int 137atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 138{ 139 int res = exp; 140 141 __asm __volatile ( 142 " " MPLOCKED " " 143 " cmpxchgl %2,%3 ; " 144 " setz %%al ; " 145 " movzbl %%al,%0 ; " 146 "1: " 147 "# atomic_cmpset_int" 148 : "=a" (res) /* 0 (result) */ 149 : "0" (exp), /* 1 */ 150 "r" (src), /* 2 */ 151 "m" (*(dst)) /* 3 */ 152 : "memory"); 153 154 return (res); 155} 156#endif /* defined(I386_CPU) */ 157 158#if defined(I386_CPU) 159/* 160 * We assume that a = b will do atomic loads and stores. 161 * 162 * XXX: This is _NOT_ safe on a P6 or higher because it does not guarantee 163 * memory ordering. These should only be used on a 386. 164 */ 165#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 166static __inline u_##TYPE \ 167atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 168{ \ 169 return (*p); \ 170} \ 171 \ 172static __inline void \ 173atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 174{ \ 175 *p = v; \ 176 __asm __volatile("" : : : "memory"); \ 177} 178#else 179 180#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 181static __inline u_##TYPE \ 182atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 183{ \ 184 u_##TYPE res; \ 185 \ 186 __asm __volatile(MPLOCKED LOP \ 187 : "=a" (res), /* 0 (result) */\ 188 "+m" (*p) /* 1 */ \ 189 : : "cc", "memory"); \ 190 \ 191 return (res); \ 192} \ 193 \ 194/* \ 195 * The XCHG instruction asserts LOCK automagically. \ 196 */ \ 197static __inline void \ 198atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 199{ \ 200 __asm __volatile(SOP \ 201 : "+m" (*p), /* 0 */ \ 202 "+r" (v) /* 1 */ \ 203 : : "memory"); \ 204} 205#endif /* defined(I386_CPU) */ 206#endif /* !defined(LOCORE) */ 207#endif /* KLD_MODULE */ 208 209#if !defined(LOCORE) 210ATOMIC_ASM(set, char, "orb %b2,%0", v) 211ATOMIC_ASM(clear, char, "andb %b2,%0", ~v) 212ATOMIC_ASM(add, char, "addb %b2,%0", v) 213ATOMIC_ASM(subtract, char, "subb %b2,%0", v) 214 215ATOMIC_ASM(set, short, "orw %w2,%0", v) 216ATOMIC_ASM(clear, short, "andw %w2,%0", ~v) 217ATOMIC_ASM(add, short, "addw %w2,%0", v) 218ATOMIC_ASM(subtract, short, "subw %w2,%0", v) 219 220ATOMIC_ASM(set, int, "orl %2,%0", v) 221ATOMIC_ASM(clear, int, "andl %2,%0", ~v) 222ATOMIC_ASM(add, int, "addl %2,%0", v) 223ATOMIC_ASM(subtract, int, "subl %2,%0", v) 224 225ATOMIC_ASM(set, long, "orl %2,%0", v) 226ATOMIC_ASM(clear, long, "andl %2,%0", ~v) 227ATOMIC_ASM(add, long, "addl %2,%0", v) 228ATOMIC_ASM(subtract, long, "subl %2,%0", v) 229 230ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0") 231ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0") 232ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0") 233ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0") 234 235#undef ATOMIC_ASM 236#undef ATOMIC_STORE_LOAD 237 238#define atomic_set_acq_char atomic_set_char 239#define atomic_set_rel_char atomic_set_char 240#define atomic_clear_acq_char atomic_clear_char 241#define atomic_clear_rel_char atomic_clear_char 242#define atomic_add_acq_char atomic_add_char 243#define atomic_add_rel_char atomic_add_char 244#define atomic_subtract_acq_char atomic_subtract_char 245#define atomic_subtract_rel_char atomic_subtract_char 246 247#define atomic_set_acq_short atomic_set_short 248#define atomic_set_rel_short atomic_set_short 249#define atomic_clear_acq_short atomic_clear_short 250#define atomic_clear_rel_short atomic_clear_short 251#define atomic_add_acq_short atomic_add_short 252#define atomic_add_rel_short atomic_add_short 253#define atomic_subtract_acq_short atomic_subtract_short 254#define atomic_subtract_rel_short atomic_subtract_short 255 256#define atomic_set_acq_int atomic_set_int 257#define atomic_set_rel_int atomic_set_int 258#define atomic_clear_acq_int atomic_clear_int 259#define atomic_clear_rel_int atomic_clear_int 260#define atomic_add_acq_int atomic_add_int 261#define atomic_add_rel_int atomic_add_int 262#define atomic_subtract_acq_int atomic_subtract_int 263#define atomic_subtract_rel_int atomic_subtract_int 264#define atomic_cmpset_acq_int atomic_cmpset_int 265#define atomic_cmpset_rel_int atomic_cmpset_int 266 267#define atomic_set_acq_long atomic_set_long 268#define atomic_set_rel_long atomic_set_long 269#define atomic_clear_acq_long atomic_clear_long 270#define atomic_clear_rel_long atomic_clear_long 271#define atomic_add_acq_long atomic_add_long 272#define atomic_add_rel_long atomic_add_long 273#define atomic_subtract_acq_long atomic_subtract_long 274#define atomic_subtract_rel_long atomic_subtract_long 275#define atomic_cmpset_long atomic_cmpset_int 276#define atomic_cmpset_acq_long atomic_cmpset_acq_int 277#define atomic_cmpset_rel_long atomic_cmpset_rel_int 278 279#define atomic_cmpset_acq_ptr atomic_cmpset_ptr 280#define atomic_cmpset_rel_ptr atomic_cmpset_ptr 281 282#define atomic_set_8 atomic_set_char 283#define atomic_set_acq_8 atomic_set_acq_char 284#define atomic_set_rel_8 atomic_set_rel_char 285#define atomic_clear_8 atomic_clear_char 286#define atomic_clear_acq_8 atomic_clear_acq_char 287#define atomic_clear_rel_8 atomic_clear_rel_char 288#define atomic_add_8 atomic_add_char 289#define atomic_add_acq_8 atomic_add_acq_char 290#define atomic_add_rel_8 atomic_add_rel_char 291#define atomic_subtract_8 atomic_subtract_char 292#define atomic_subtract_acq_8 atomic_subtract_acq_char 293#define atomic_subtract_rel_8 atomic_subtract_rel_char 294#define atomic_load_acq_8 atomic_load_acq_char 295#define atomic_store_rel_8 atomic_store_rel_char 296 297#define atomic_set_16 atomic_set_short 298#define atomic_set_acq_16 atomic_set_acq_short 299#define atomic_set_rel_16 atomic_set_rel_short 300#define atomic_clear_16 atomic_clear_short 301#define atomic_clear_acq_16 atomic_clear_acq_short 302#define atomic_clear_rel_16 atomic_clear_rel_short 303#define atomic_add_16 atomic_add_short 304#define atomic_add_acq_16 atomic_add_acq_short 305#define atomic_add_rel_16 atomic_add_rel_short 306#define atomic_subtract_16 atomic_subtract_short 307#define atomic_subtract_acq_16 atomic_subtract_acq_short 308#define atomic_subtract_rel_16 atomic_subtract_rel_short 309#define atomic_load_acq_16 atomic_load_acq_short 310#define atomic_store_rel_16 atomic_store_rel_short 311 312#define atomic_set_32 atomic_set_int 313#define atomic_set_acq_32 atomic_set_acq_int 314#define atomic_set_rel_32 atomic_set_rel_int 315#define atomic_clear_32 atomic_clear_int 316#define atomic_clear_acq_32 atomic_clear_acq_int 317#define atomic_clear_rel_32 atomic_clear_rel_int 318#define atomic_add_32 atomic_add_int 319#define atomic_add_acq_32 atomic_add_acq_int 320#define atomic_add_rel_32 atomic_add_rel_int 321#define atomic_subtract_32 atomic_subtract_int 322#define atomic_subtract_acq_32 atomic_subtract_acq_int 323#define atomic_subtract_rel_32 atomic_subtract_rel_int 324#define atomic_load_acq_32 atomic_load_acq_int 325#define atomic_store_rel_32 atomic_store_rel_int 326#define atomic_cmpset_32 atomic_cmpset_int 327#define atomic_cmpset_acq_32 atomic_cmpset_acq_int 328#define atomic_cmpset_rel_32 atomic_cmpset_rel_int 329#define atomic_readandclear_32 atomic_readandclear_int 330 331#if !defined(WANT_FUNCTIONS) 332static __inline int 333atomic_cmpset_ptr(volatile void *dst, void *exp, void *src) 334{ 335 336 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 337 (u_int)src)); 338} 339 340static __inline void * 341atomic_load_acq_ptr(volatile void *p) 342{ 343 return (void *)atomic_load_acq_int((volatile u_int *)p); 344} 345 346static __inline void 347atomic_store_rel_ptr(volatile void *p, void *v) 348{ 349 atomic_store_rel_int((volatile u_int *)p, (u_int)v); 350} 351 352#define ATOMIC_PTR(NAME) \ 353static __inline void \ 354atomic_##NAME##_ptr(volatile void *p, uintptr_t v) \ 355{ \ 356 atomic_##NAME##_int((volatile u_int *)p, v); \ 357} \ 358 \ 359static __inline void \ 360atomic_##NAME##_acq_ptr(volatile void *p, uintptr_t v) \ 361{ \ 362 atomic_##NAME##_acq_int((volatile u_int *)p, v);\ 363} \ 364 \ 365static __inline void \ 366atomic_##NAME##_rel_ptr(volatile void *p, uintptr_t v) \ 367{ \ 368 atomic_##NAME##_rel_int((volatile u_int *)p, v);\ 369} 370 371ATOMIC_PTR(set) 372ATOMIC_PTR(clear) 373ATOMIC_PTR(add) 374ATOMIC_PTR(subtract) 375 376#undef ATOMIC_PTR 377 378static __inline u_int 379atomic_readandclear_int(volatile u_int *addr) 380{ 381 u_int result; 382 383 __asm __volatile ( 384 " xorl %0,%0 ; " 385 " xchgl %1,%0 ; " 386 "# atomic_readandclear_int" 387 : "=&r" (result) /* 0 (result) */ 388 : "m" (*addr)); /* 1 (addr) */ 389 390 return (result); 391} 392 393static __inline u_long 394atomic_readandclear_long(volatile u_long *addr) 395{ 396 u_long result; 397 398 __asm __volatile ( 399 " xorl %0,%0 ; " 400 " xchgl %1,%0 ; " 401 "# atomic_readandclear_int" 402 : "=&r" (result) /* 0 (result) */ 403 : "m" (*addr)); /* 1 (addr) */ 404 405 return (result); 406} 407#endif /* !defined(WANT_FUNCTIONS) */ 408#endif /* !defined(LOCORE) */ 409#endif /* ! _MACHINE_ATOMIC_H_ */ 410