Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/i386/include/atomic.h
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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: releng/8.2/sys/i386/include/atomic.h 199583 2009-11-20 15:27:52Z jhb $ 27 */ 28 #ifndef _MACHINE_ATOMIC_H_ 29 #define _MACHINE_ATOMIC_H_ 30 31 #ifndef _SYS_CDEFS_H_ 32 #error this file needs sys/cdefs.h as a prerequisite 33 #endif 34 35 #define mb() __asm __volatile("lock; addl $0,(%%esp)" : : : "memory") 36 #define wmb() __asm __volatile("lock; addl $0,(%%esp)" : : : "memory") 37 #define rmb() __asm __volatile("lock; addl $0,(%%esp)" : : : "memory") 38 39 /* 40 * Various simple operations on memory, each of which is atomic in the 41 * presence of interrupts and multiple processors. 42 * 43 * atomic_set_char(P, V) (*(u_char *)(P) |= (V)) 44 * atomic_clear_char(P, V) (*(u_char *)(P) &= ~(V)) 45 * atomic_add_char(P, V) (*(u_char *)(P) += (V)) 46 * atomic_subtract_char(P, V) (*(u_char *)(P) -= (V)) 47 * 48 * atomic_set_short(P, V) (*(u_short *)(P) |= (V)) 49 * atomic_clear_short(P, V) (*(u_short *)(P) &= ~(V)) 50 * atomic_add_short(P, V) (*(u_short *)(P) += (V)) 51 * atomic_subtract_short(P, V) (*(u_short *)(P) -= (V)) 52 * 53 * atomic_set_int(P, V) (*(u_int *)(P) |= (V)) 54 * atomic_clear_int(P, V) (*(u_int *)(P) &= ~(V)) 55 * atomic_add_int(P, V) (*(u_int *)(P) += (V)) 56 * atomic_subtract_int(P, V) (*(u_int *)(P) -= (V)) 57 * atomic_readandclear_int(P) (return (*(u_int *)(P)); *(u_int *)(P) = 0;) 58 * 59 * atomic_set_long(P, V) (*(u_long *)(P) |= (V)) 60 * atomic_clear_long(P, V) (*(u_long *)(P) &= ~(V)) 61 * atomic_add_long(P, V) (*(u_long *)(P) += (V)) 62 * atomic_subtract_long(P, V) (*(u_long *)(P) -= (V)) 63 * atomic_readandclear_long(P) (return (*(u_long *)(P)); *(u_long *)(P) = 0;) 64 */ 65 66 /* 67 * The above functions are expanded inline in the statically-linked 68 * kernel. Lock prefixes are generated if an SMP kernel is being 69 * built. 70 * 71 * Kernel modules call real functions which are built into the kernel. 72 * This allows kernel modules to be portable between UP and SMP systems. 73 */ 74 #if defined(KLD_MODULE) || !defined(__GNUCLIKE_ASM) 75 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 76 void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v); \ 77 void atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 78 79 int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src); 80 u_int atomic_fetchadd_int(volatile u_int *p, u_int v); 81 82 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 83 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 84 void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 85 86 #else /* !KLD_MODULE && __GNUCLIKE_ASM */ 87 88 /* 89 * For userland, always use lock prefixes so that the binaries will run 90 * on both SMP and !SMP systems. 91 */ 92 #if defined(SMP) || !defined(_KERNEL) 93 #define MPLOCKED "lock ; " 94 #else 95 #define MPLOCKED 96 #endif 97 98 /* 99 * The assembly is volatilized to avoid code chunk removal by the compiler. 100 * GCC aggressively reorders operations and memory clobbering is necessary 101 * in order to avoid that for memory barriers. 102 */ 103 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 104 static __inline void \ 105 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 106 { \ 107 __asm __volatile(MPLOCKED OP \ 108 : "=m" (*p) \ 109 : CONS (V), "m" (*p)); \ 110 } \ 111 \ 112 static __inline void \ 113 atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 114 { \ 115 __asm __volatile(MPLOCKED OP \ 116 : "=m" (*p) \ 117 : CONS (V), "m" (*p) \ 118 : "memory"); \ 119 } \ 120 struct __hack 121 122 /* 123 * Atomic compare and set, used by the mutex functions 124 * 125 * if (*dst == exp) *dst = src (all 32 bit words) 126 * 127 * Returns 0 on failure, non-zero on success 128 */ 129 130 #ifdef CPU_DISABLE_CMPXCHG 131 132 static __inline int 133 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 134 { 135 u_char res; 136 137 __asm __volatile( 138 " pushfl ; " 139 " cli ; " 140 " cmpl %3,%4 ; " 141 " jne 1f ; " 142 " movl %2,%1 ; " 143 "1: " 144 " sete %0 ; " 145 " popfl ; " 146 "# atomic_cmpset_int" 147 : "=q" (res), /* 0 */ 148 "=m" (*dst) /* 1 */ 149 : "r" (src), /* 2 */ 150 "r" (exp), /* 3 */ 151 "m" (*dst) /* 4 */ 152 : "memory"); 153 154 return (res); 155 } 156 157 #else /* !CPU_DISABLE_CMPXCHG */ 158 159 static __inline int 160 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 161 { 162 u_char res; 163 164 __asm __volatile( 165 " " MPLOCKED " " 166 " cmpxchgl %2,%1 ; " 167 " sete %0 ; " 168 "1: " 169 "# atomic_cmpset_int" 170 : "=a" (res), /* 0 */ 171 "=m" (*dst) /* 1 */ 172 : "r" (src), /* 2 */ 173 "a" (exp), /* 3 */ 174 "m" (*dst) /* 4 */ 175 : "memory"); 176 177 return (res); 178 } 179 180 #endif /* CPU_DISABLE_CMPXCHG */ 181 182 /* 183 * Atomically add the value of v to the integer pointed to by p and return 184 * the previous value of *p. 185 */ 186 static __inline u_int 187 atomic_fetchadd_int(volatile u_int *p, u_int v) 188 { 189 190 __asm __volatile( 191 " " MPLOCKED " " 192 " xaddl %0, %1 ; " 193 "# atomic_fetchadd_int" 194 : "+r" (v), /* 0 (result) */ 195 "=m" (*p) /* 1 */ 196 : "m" (*p)); /* 2 */ 197 198 return (v); 199 } 200 201 #if defined(_KERNEL) && !defined(SMP) 202 203 /* 204 * We assume that a = b will do atomic loads and stores. However, on a 205 * PentiumPro or higher, reads may pass writes, so for that case we have 206 * to use a serializing instruction (i.e. with LOCK) to do the load in 207 * SMP kernels. For UP kernels, however, the cache of the single processor 208 * is always consistent, so we only need to take care of compiler. 209 */ 210 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 211 static __inline u_##TYPE \ 212 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 213 { \ 214 u_##TYPE tmp; \ 215 \ 216 tmp = *p; \ 217 __asm __volatile("" : : : "memory"); \ 218 return (tmp); \ 219 } \ 220 \ 221 static __inline void \ 222 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 223 { \ 224 __asm __volatile("" : : : "memory"); \ 225 *p = v; \ 226 } \ 227 struct __hack 228 229 #else /* !(_KERNEL && !SMP) */ 230 231 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 232 static __inline u_##TYPE \ 233 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 234 { \ 235 u_##TYPE res; \ 236 \ 237 __asm __volatile(MPLOCKED LOP \ 238 : "=a" (res), /* 0 */ \ 239 "=m" (*p) /* 1 */ \ 240 : "m" (*p) /* 2 */ \ 241 : "memory"); \ 242 \ 243 return (res); \ 244 } \ 245 \ 246 /* \ 247 * The XCHG instruction asserts LOCK automagically. \ 248 */ \ 249 static __inline void \ 250 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 251 { \ 252 __asm __volatile(SOP \ 253 : "=m" (*p), /* 0 */ \ 254 "+r" (v) /* 1 */ \ 255 : "m" (*p) /* 2 */ \ 256 : "memory"); \ 257 } \ 258 struct __hack 259 260 #endif /* _KERNEL && !SMP */ 261 262 #endif /* KLD_MODULE || !__GNUCLIKE_ASM */ 263 264 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 265 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 266 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 267 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 268 269 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 270 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 271 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 272 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 273 274 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 275 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 276 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 277 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 278 279 ATOMIC_ASM(set, long, "orl %1,%0", "ir", v); 280 ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v); 281 ATOMIC_ASM(add, long, "addl %1,%0", "ir", v); 282 ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v); 283 284 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 285 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 286 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 287 ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0"); 288 289 #undef ATOMIC_ASM 290 #undef ATOMIC_STORE_LOAD 291 292 #ifndef WANT_FUNCTIONS 293 294 static __inline int 295 atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src) 296 { 297 298 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 299 (u_int)src)); 300 } 301 302 static __inline u_long 303 atomic_fetchadd_long(volatile u_long *p, u_long v) 304 { 305 306 return (atomic_fetchadd_int((volatile u_int *)p, (u_int)v)); 307 } 308 309 /* Read the current value and store a zero in the destination. */ 310 #ifdef __GNUCLIKE_ASM 311 312 static __inline u_int 313 atomic_readandclear_int(volatile u_int *addr) 314 { 315 u_int res; 316 317 res = 0; 318 __asm __volatile( 319 " xchgl %1,%0 ; " 320 "# atomic_readandclear_int" 321 : "+r" (res), /* 0 */ 322 "=m" (*addr) /* 1 */ 323 : "m" (*addr)); 324 325 return (res); 326 } 327 328 static __inline u_long 329 atomic_readandclear_long(volatile u_long *addr) 330 { 331 u_long res; 332 333 res = 0; 334 __asm __volatile( 335 " xchgl %1,%0 ; " 336 "# atomic_readandclear_long" 337 : "+r" (res), /* 0 */ 338 "=m" (*addr) /* 1 */ 339 : "m" (*addr)); 340 341 return (res); 342 } 343 344 #else /* !__GNUCLIKE_ASM */ 345 346 u_int atomic_readandclear_int(volatile u_int *addr); 347 u_long atomic_readandclear_long(volatile u_long *addr); 348 349 #endif /* __GNUCLIKE_ASM */ 350 351 #define atomic_set_acq_char atomic_set_barr_char 352 #define atomic_set_rel_char atomic_set_barr_char 353 #define atomic_clear_acq_char atomic_clear_barr_char 354 #define atomic_clear_rel_char atomic_clear_barr_char 355 #define atomic_add_acq_char atomic_add_barr_char 356 #define atomic_add_rel_char atomic_add_barr_char 357 #define atomic_subtract_acq_char atomic_subtract_barr_char 358 #define atomic_subtract_rel_char atomic_subtract_barr_char 359 360 #define atomic_set_acq_short atomic_set_barr_short 361 #define atomic_set_rel_short atomic_set_barr_short 362 #define atomic_clear_acq_short atomic_clear_barr_short 363 #define atomic_clear_rel_short atomic_clear_barr_short 364 #define atomic_add_acq_short atomic_add_barr_short 365 #define atomic_add_rel_short atomic_add_barr_short 366 #define atomic_subtract_acq_short atomic_subtract_barr_short 367 #define atomic_subtract_rel_short atomic_subtract_barr_short 368 369 #define atomic_set_acq_int atomic_set_barr_int 370 #define atomic_set_rel_int atomic_set_barr_int 371 #define atomic_clear_acq_int atomic_clear_barr_int 372 #define atomic_clear_rel_int atomic_clear_barr_int 373 #define atomic_add_acq_int atomic_add_barr_int 374 #define atomic_add_rel_int atomic_add_barr_int 375 #define atomic_subtract_acq_int atomic_subtract_barr_int 376 #define atomic_subtract_rel_int atomic_subtract_barr_int 377 #define atomic_cmpset_acq_int atomic_cmpset_int 378 #define atomic_cmpset_rel_int atomic_cmpset_int 379 380 #define atomic_set_acq_long atomic_set_barr_long 381 #define atomic_set_rel_long atomic_set_barr_long 382 #define atomic_clear_acq_long atomic_clear_barr_long 383 #define atomic_clear_rel_long atomic_clear_barr_long 384 #define atomic_add_acq_long atomic_add_barr_long 385 #define atomic_add_rel_long atomic_add_barr_long 386 #define atomic_subtract_acq_long atomic_subtract_barr_long 387 #define atomic_subtract_rel_long atomic_subtract_barr_long 388 #define atomic_cmpset_acq_long atomic_cmpset_long 389 #define atomic_cmpset_rel_long atomic_cmpset_long 390 391 /* Operations on 8-bit bytes. */ 392 #define atomic_set_8 atomic_set_char 393 #define atomic_set_acq_8 atomic_set_acq_char 394 #define atomic_set_rel_8 atomic_set_rel_char 395 #define atomic_clear_8 atomic_clear_char 396 #define atomic_clear_acq_8 atomic_clear_acq_char 397 #define atomic_clear_rel_8 atomic_clear_rel_char 398 #define atomic_add_8 atomic_add_char 399 #define atomic_add_acq_8 atomic_add_acq_char 400 #define atomic_add_rel_8 atomic_add_rel_char 401 #define atomic_subtract_8 atomic_subtract_char 402 #define atomic_subtract_acq_8 atomic_subtract_acq_char 403 #define atomic_subtract_rel_8 atomic_subtract_rel_char 404 #define atomic_load_acq_8 atomic_load_acq_char 405 #define atomic_store_rel_8 atomic_store_rel_char 406 407 /* Operations on 16-bit words. */ 408 #define atomic_set_16 atomic_set_short 409 #define atomic_set_acq_16 atomic_set_acq_short 410 #define atomic_set_rel_16 atomic_set_rel_short 411 #define atomic_clear_16 atomic_clear_short 412 #define atomic_clear_acq_16 atomic_clear_acq_short 413 #define atomic_clear_rel_16 atomic_clear_rel_short 414 #define atomic_add_16 atomic_add_short 415 #define atomic_add_acq_16 atomic_add_acq_short 416 #define atomic_add_rel_16 atomic_add_rel_short 417 #define atomic_subtract_16 atomic_subtract_short 418 #define atomic_subtract_acq_16 atomic_subtract_acq_short 419 #define atomic_subtract_rel_16 atomic_subtract_rel_short 420 #define atomic_load_acq_16 atomic_load_acq_short 421 #define atomic_store_rel_16 atomic_store_rel_short 422 423 /* Operations on 32-bit double words. */ 424 #define atomic_set_32 atomic_set_int 425 #define atomic_set_acq_32 atomic_set_acq_int 426 #define atomic_set_rel_32 atomic_set_rel_int 427 #define atomic_clear_32 atomic_clear_int 428 #define atomic_clear_acq_32 atomic_clear_acq_int 429 #define atomic_clear_rel_32 atomic_clear_rel_int 430 #define atomic_add_32 atomic_add_int 431 #define atomic_add_acq_32 atomic_add_acq_int 432 #define atomic_add_rel_32 atomic_add_rel_int 433 #define atomic_subtract_32 atomic_subtract_int 434 #define atomic_subtract_acq_32 atomic_subtract_acq_int 435 #define atomic_subtract_rel_32 atomic_subtract_rel_int 436 #define atomic_load_acq_32 atomic_load_acq_int 437 #define atomic_store_rel_32 atomic_store_rel_int 438 #define atomic_cmpset_32 atomic_cmpset_int 439 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int 440 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int 441 #define atomic_readandclear_32 atomic_readandclear_int 442 #define atomic_fetchadd_32 atomic_fetchadd_int 443 444 /* Operations on pointers. */ 445 #define atomic_set_ptr(p, v) \ 446 atomic_set_int((volatile u_int *)(p), (u_int)(v)) 447 #define atomic_set_acq_ptr(p, v) \ 448 atomic_set_acq_int((volatile u_int *)(p), (u_int)(v)) 449 #define atomic_set_rel_ptr(p, v) \ 450 atomic_set_rel_int((volatile u_int *)(p), (u_int)(v)) 451 #define atomic_clear_ptr(p, v) \ 452 atomic_clear_int((volatile u_int *)(p), (u_int)(v)) 453 #define atomic_clear_acq_ptr(p, v) \ 454 atomic_clear_acq_int((volatile u_int *)(p), (u_int)(v)) 455 #define atomic_clear_rel_ptr(p, v) \ 456 atomic_clear_rel_int((volatile u_int *)(p), (u_int)(v)) 457 #define atomic_add_ptr(p, v) \ 458 atomic_add_int((volatile u_int *)(p), (u_int)(v)) 459 #define atomic_add_acq_ptr(p, v) \ 460 atomic_add_acq_int((volatile u_int *)(p), (u_int)(v)) 461 #define atomic_add_rel_ptr(p, v) \ 462 atomic_add_rel_int((volatile u_int *)(p), (u_int)(v)) 463 #define atomic_subtract_ptr(p, v) \ 464 atomic_subtract_int((volatile u_int *)(p), (u_int)(v)) 465 #define atomic_subtract_acq_ptr(p, v) \ 466 atomic_subtract_acq_int((volatile u_int *)(p), (u_int)(v)) 467 #define atomic_subtract_rel_ptr(p, v) \ 468 atomic_subtract_rel_int((volatile u_int *)(p), (u_int)(v)) 469 #define atomic_load_acq_ptr(p) \ 470 atomic_load_acq_int((volatile u_int *)(p)) 471 #define atomic_store_rel_ptr(p, v) \ 472 atomic_store_rel_int((volatile u_int *)(p), (v)) 473 #define atomic_cmpset_ptr(dst, old, new) \ 474 atomic_cmpset_int((volatile u_int *)(dst), (u_int)(old), (u_int)(new)) 475 #define atomic_cmpset_acq_ptr(dst, old, new) \ 476 atomic_cmpset_acq_int((volatile u_int *)(dst), (u_int)(old), \ 477 (u_int)(new)) 478 #define atomic_cmpset_rel_ptr(dst, old, new) \ 479 atomic_cmpset_rel_int((volatile u_int *)(dst), (u_int)(old), \ 480 (u_int)(new)) 481 #define atomic_readandclear_ptr(p) \ 482 atomic_readandclear_int((volatile u_int *)(p)) 483 484 #endif /* !WANT_FUNCTIONS */ 485 486 #endif /* !_MACHINE_ATOMIC_H_ */
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