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 #ifndef _SYS_CDEFS_H_ 32 #error this file needs sys/cdefs.h as a prerequisite 33 #endif 34 35 #define mb() __asm __volatile("mfence;" : : : "memory") 36 #define wmb() __asm __volatile("sfence;" : : : "memory") 37 #define rmb() __asm __volatile("lfence;" : : : "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_swap_int(P, V) (return (*(u_int *)(P)); *(u_int *)(P) = (V);) 58 * atomic_readandclear_int(P) (return (*(u_int *)(P)); *(u_int *)(P) = 0;) 59 * 60 * atomic_set_long(P, V) (*(u_long *)(P) |= (V)) 61 * atomic_clear_long(P, V) (*(u_long *)(P) &= ~(V)) 62 * atomic_add_long(P, V) (*(u_long *)(P) += (V)) 63 * atomic_subtract_long(P, V) (*(u_long *)(P) -= (V)) 64 * atomic_swap_long(P, V) (return (*(u_long *)(P)); *(u_long *)(P) = (V);) 65 * atomic_readandclear_long(P) (return (*(u_long *)(P)); *(u_long *)(P) = 0;) 66 */ 67 68 /* 69 * The above functions are expanded inline in the statically-linked 70 * kernel. Lock prefixes are generated if an SMP kernel is being 71 * built. 72 * 73 * Kernel modules call real functions which are built into the kernel. 74 * This allows kernel modules to be portable between UP and SMP systems. 75 */ 76 #if defined(KLD_MODULE) || !defined(__GNUCLIKE_ASM) 77 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 78 void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v); \ 79 void atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 80 81 int atomic_cmpset_int(volatile u_int *dst, u_int expect, u_int src); 82 int atomic_cmpset_long(volatile u_long *dst, u_long expect, u_long src); 83 u_int atomic_fetchadd_int(volatile u_int *p, u_int v); 84 u_long atomic_fetchadd_long(volatile u_long *p, u_long v); 85 int atomic_testandset_int(volatile u_int *p, u_int v); 86 int atomic_testandset_long(volatile u_long *p, u_int v); 87 88 #define ATOMIC_LOAD(TYPE) \ 89 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p) 90 #define ATOMIC_STORE(TYPE) \ 91 void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 92 93 #else /* !KLD_MODULE && __GNUCLIKE_ASM */ 94 95 /* 96 * For userland, always use lock prefixes so that the binaries will run 97 * on both SMP and !SMP systems. 98 */ 99 #if defined(SMP) || !defined(_KERNEL) 100 #define MPLOCKED "lock ; " 101 #else 102 #define MPLOCKED 103 #endif 104 105 /* 106 * The assembly is volatilized to avoid code chunk removal by the compiler. 107 * GCC aggressively reorders operations and memory clobbering is necessary 108 * in order to avoid that for memory barriers. 109 */ 110 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 111 static __inline void \ 112 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 113 { \ 114 __asm __volatile(MPLOCKED OP \ 115 : "+m" (*p) \ 116 : CONS (V) \ 117 : "cc"); \ 118 } \ 119 \ 120 static __inline void \ 121 atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 122 { \ 123 __asm __volatile(MPLOCKED OP \ 124 : "+m" (*p) \ 125 : CONS (V) \ 126 : "memory", "cc"); \ 127 } \ 128 struct __hack 129 130 /* 131 * Atomic compare and set, used by the mutex functions 132 * 133 * if (*dst == expect) *dst = src (all 32 bit words) 134 * 135 * Returns 0 on failure, non-zero on success 136 */ 137 138 static __inline int 139 atomic_cmpset_int(volatile u_int *dst, u_int expect, u_int src) 140 { 141 u_char res; 142 143 __asm __volatile( 144 " " MPLOCKED " " 145 " cmpxchgl %3,%1 ; " 146 " sete %0 ; " 147 "# atomic_cmpset_int" 148 : "=q" (res), /* 0 */ 149 "+m" (*dst), /* 1 */ 150 "+a" (expect) /* 2 */ 151 : "r" (src) /* 3 */ 152 : "memory", "cc"); 153 return (res); 154 } 155 156 static __inline int 157 atomic_cmpset_long(volatile u_long *dst, u_long expect, u_long src) 158 { 159 u_char res; 160 161 __asm __volatile( 162 " " MPLOCKED " " 163 " cmpxchgq %3,%1 ; " 164 " sete %0 ; " 165 "# atomic_cmpset_long" 166 : "=q" (res), /* 0 */ 167 "+m" (*dst), /* 1 */ 168 "+a" (expect) /* 2 */ 169 : "r" (src) /* 3 */ 170 : "memory", "cc"); 171 return (res); 172 } 173 174 /* 175 * Atomically add the value of v to the integer pointed to by p and return 176 * the previous value of *p. 177 */ 178 static __inline u_int 179 atomic_fetchadd_int(volatile u_int *p, u_int v) 180 { 181 182 __asm __volatile( 183 " " MPLOCKED " " 184 " xaddl %0,%1 ; " 185 "# atomic_fetchadd_int" 186 : "+r" (v), /* 0 */ 187 "+m" (*p) /* 1 */ 188 : : "cc"); 189 return (v); 190 } 191 192 /* 193 * Atomically add the value of v to the long integer pointed to by p and return 194 * the previous value of *p. 195 */ 196 static __inline u_long 197 atomic_fetchadd_long(volatile u_long *p, u_long v) 198 { 199 200 __asm __volatile( 201 " " MPLOCKED " " 202 " xaddq %0,%1 ; " 203 "# atomic_fetchadd_long" 204 : "+r" (v), /* 0 */ 205 "+m" (*p) /* 1 */ 206 : : "cc"); 207 return (v); 208 } 209 210 static __inline int 211 atomic_testandset_int(volatile u_int *p, u_int v) 212 { 213 u_char res; 214 215 __asm __volatile( 216 " " MPLOCKED " " 217 " btsl %2,%1 ; " 218 " setc %0 ; " 219 "# atomic_testandset_int" 220 : "=q" (res), /* 0 */ 221 "+m" (*p) /* 1 */ 222 : "Ir" (v & 0x1f) /* 2 */ 223 : "cc"); 224 return (res); 225 } 226 227 static __inline int 228 atomic_testandset_long(volatile u_long *p, u_int v) 229 { 230 u_char res; 231 232 __asm __volatile( 233 " " MPLOCKED " " 234 " btsq %2,%1 ; " 235 " setc %0 ; " 236 "# atomic_testandset_long" 237 : "=q" (res), /* 0 */ 238 "+m" (*p) /* 1 */ 239 : "Jr" ((u_long)(v & 0x3f)) /* 2 */ 240 : "cc"); 241 return (res); 242 } 243 244 /* 245 * We assume that a = b will do atomic loads and stores. Due to the 246 * IA32 memory model, a simple store guarantees release semantics. 247 * 248 * However, a load may pass a store if they are performed on distinct 249 * addresses, so for atomic_load_acq we introduce a Store/Load barrier 250 * before the load in SMP kernels. We use "lock addl $0,mem", as 251 * recommended by the AMD Software Optimization Guide, and not mfence. 252 * In the kernel, we use a private per-cpu cache line as the target 253 * for the locked addition, to avoid introducing false data 254 * dependencies. In userspace, a word in the red zone on the stack 255 * (-8(%rsp)) is utilized. 256 * 257 * For UP kernels, however, the memory of the single processor is 258 * always consistent, so we only need to stop the compiler from 259 * reordering accesses in a way that violates the semantics of acquire 260 * and release. 261 */ 262 263 #if defined(_KERNEL) 264 265 /* 266 * OFFSETOF_MONITORBUF == __pcpu_offset(pc_monitorbuf). 267 * 268 * The open-coded number is used instead of the symbolic expression to 269 * avoid a dependency on sys/pcpu.h in machine/atomic.h consumers. 270 * An assertion in amd64/vm_machdep.c ensures that the value is correct. 271 */ 272 #define OFFSETOF_MONITORBUF 0x180 273 274 #if defined(SMP) 275 static __inline void 276 __storeload_barrier(void) 277 { 278 279 __asm __volatile("lock; addl $0,%%gs:%0" 280 : "+m" (*(u_int *)OFFSETOF_MONITORBUF) : : "memory", "cc"); 281 } 282 #else /* _KERNEL && UP */ 283 static __inline void 284 __storeload_barrier(void) 285 { 286 287 __compiler_membar(); 288 } 289 #endif /* SMP */ 290 #else /* !_KERNEL */ 291 static __inline void 292 __storeload_barrier(void) 293 { 294 295 __asm __volatile("lock; addl $0,-8(%%rsp)" : : : "memory", "cc"); 296 } 297 #endif /* _KERNEL*/ 298 299 /* 300 * C11-standard acq/rel semantics only apply when the variable in the 301 * call is the same for acq as it is for rel. However, our previous 302 * (x86) implementations provided much stronger ordering than required 303 * (essentially what is called seq_cst order in C11). This 304 * implementation provides the historical strong ordering since some 305 * callers depend on it. 306 */ 307 308 #define ATOMIC_LOAD(TYPE) \ 309 static __inline u_##TYPE \ 310 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 311 { \ 312 u_##TYPE res; \ 313 \ 314 __storeload_barrier(); \ 315 res = *p; \ 316 __compiler_membar(); \ 317 return (res); \ 318 } \ 319 struct __hack 320 321 #define ATOMIC_STORE(TYPE) \ 322 static __inline void \ 323 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) \ 324 { \ 325 \ 326 __compiler_membar(); \ 327 *p = v; \ 328 } \ 329 struct __hack 330 331 #endif /* KLD_MODULE || !__GNUCLIKE_ASM */ 332 333 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 334 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 335 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 336 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 337 338 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 339 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 340 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 341 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 342 343 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 344 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 345 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 346 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 347 348 ATOMIC_ASM(set, long, "orq %1,%0", "ir", v); 349 ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v); 350 ATOMIC_ASM(add, long, "addq %1,%0", "ir", v); 351 ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v); 352 353 #define ATOMIC_LOADSTORE(TYPE) \ 354 ATOMIC_LOAD(TYPE); \ 355 ATOMIC_STORE(TYPE) 356 357 ATOMIC_LOADSTORE(char); 358 ATOMIC_LOADSTORE(short); 359 ATOMIC_LOADSTORE(int); 360 ATOMIC_LOADSTORE(long); 361 362 #undef ATOMIC_ASM 363 #undef ATOMIC_LOAD 364 #undef ATOMIC_STORE 365 #undef ATOMIC_LOADSTORE 366 #ifndef WANT_FUNCTIONS 367 368 /* Read the current value and store a new value in the destination. */ 369 #ifdef __GNUCLIKE_ASM 370 371 static __inline u_int 372 atomic_swap_int(volatile u_int *p, u_int v) 373 { 374 375 __asm __volatile( 376 " xchgl %1,%0 ; " 377 "# atomic_swap_int" 378 : "+r" (v), /* 0 */ 379 "+m" (*p)); /* 1 */ 380 return (v); 381 } 382 383 static __inline u_long 384 atomic_swap_long(volatile u_long *p, u_long v) 385 { 386 387 __asm __volatile( 388 " xchgq %1,%0 ; " 389 "# atomic_swap_long" 390 : "+r" (v), /* 0 */ 391 "+m" (*p)); /* 1 */ 392 return (v); 393 } 394 395 #else /* !__GNUCLIKE_ASM */ 396 397 u_int atomic_swap_int(volatile u_int *p, u_int v); 398 u_long atomic_swap_long(volatile u_long *p, u_long v); 399 400 #endif /* __GNUCLIKE_ASM */ 401 402 #define atomic_set_acq_char atomic_set_barr_char 403 #define atomic_set_rel_char atomic_set_barr_char 404 #define atomic_clear_acq_char atomic_clear_barr_char 405 #define atomic_clear_rel_char atomic_clear_barr_char 406 #define atomic_add_acq_char atomic_add_barr_char 407 #define atomic_add_rel_char atomic_add_barr_char 408 #define atomic_subtract_acq_char atomic_subtract_barr_char 409 #define atomic_subtract_rel_char atomic_subtract_barr_char 410 411 #define atomic_set_acq_short atomic_set_barr_short 412 #define atomic_set_rel_short atomic_set_barr_short 413 #define atomic_clear_acq_short atomic_clear_barr_short 414 #define atomic_clear_rel_short atomic_clear_barr_short 415 #define atomic_add_acq_short atomic_add_barr_short 416 #define atomic_add_rel_short atomic_add_barr_short 417 #define atomic_subtract_acq_short atomic_subtract_barr_short 418 #define atomic_subtract_rel_short atomic_subtract_barr_short 419 420 #define atomic_set_acq_int atomic_set_barr_int 421 #define atomic_set_rel_int atomic_set_barr_int 422 #define atomic_clear_acq_int atomic_clear_barr_int 423 #define atomic_clear_rel_int atomic_clear_barr_int 424 #define atomic_add_acq_int atomic_add_barr_int 425 #define atomic_add_rel_int atomic_add_barr_int 426 #define atomic_subtract_acq_int atomic_subtract_barr_int 427 #define atomic_subtract_rel_int atomic_subtract_barr_int 428 #define atomic_cmpset_acq_int atomic_cmpset_int 429 #define atomic_cmpset_rel_int atomic_cmpset_int 430 431 #define atomic_set_acq_long atomic_set_barr_long 432 #define atomic_set_rel_long atomic_set_barr_long 433 #define atomic_clear_acq_long atomic_clear_barr_long 434 #define atomic_clear_rel_long atomic_clear_barr_long 435 #define atomic_add_acq_long atomic_add_barr_long 436 #define atomic_add_rel_long atomic_add_barr_long 437 #define atomic_subtract_acq_long atomic_subtract_barr_long 438 #define atomic_subtract_rel_long atomic_subtract_barr_long 439 #define atomic_cmpset_acq_long atomic_cmpset_long 440 #define atomic_cmpset_rel_long atomic_cmpset_long 441 442 #define atomic_readandclear_int(p) atomic_swap_int(p, 0) 443 #define atomic_readandclear_long(p) atomic_swap_long(p, 0) 444 445 /* Operations on 8-bit bytes. */ 446 #define atomic_set_8 atomic_set_char 447 #define atomic_set_acq_8 atomic_set_acq_char 448 #define atomic_set_rel_8 atomic_set_rel_char 449 #define atomic_clear_8 atomic_clear_char 450 #define atomic_clear_acq_8 atomic_clear_acq_char 451 #define atomic_clear_rel_8 atomic_clear_rel_char 452 #define atomic_add_8 atomic_add_char 453 #define atomic_add_acq_8 atomic_add_acq_char 454 #define atomic_add_rel_8 atomic_add_rel_char 455 #define atomic_subtract_8 atomic_subtract_char 456 #define atomic_subtract_acq_8 atomic_subtract_acq_char 457 #define atomic_subtract_rel_8 atomic_subtract_rel_char 458 #define atomic_load_acq_8 atomic_load_acq_char 459 #define atomic_store_rel_8 atomic_store_rel_char 460 461 /* Operations on 16-bit words. */ 462 #define atomic_set_16 atomic_set_short 463 #define atomic_set_acq_16 atomic_set_acq_short 464 #define atomic_set_rel_16 atomic_set_rel_short 465 #define atomic_clear_16 atomic_clear_short 466 #define atomic_clear_acq_16 atomic_clear_acq_short 467 #define atomic_clear_rel_16 atomic_clear_rel_short 468 #define atomic_add_16 atomic_add_short 469 #define atomic_add_acq_16 atomic_add_acq_short 470 #define atomic_add_rel_16 atomic_add_rel_short 471 #define atomic_subtract_16 atomic_subtract_short 472 #define atomic_subtract_acq_16 atomic_subtract_acq_short 473 #define atomic_subtract_rel_16 atomic_subtract_rel_short 474 #define atomic_load_acq_16 atomic_load_acq_short 475 #define atomic_store_rel_16 atomic_store_rel_short 476 477 /* Operations on 32-bit double words. */ 478 #define atomic_set_32 atomic_set_int 479 #define atomic_set_acq_32 atomic_set_acq_int 480 #define atomic_set_rel_32 atomic_set_rel_int 481 #define atomic_clear_32 atomic_clear_int 482 #define atomic_clear_acq_32 atomic_clear_acq_int 483 #define atomic_clear_rel_32 atomic_clear_rel_int 484 #define atomic_add_32 atomic_add_int 485 #define atomic_add_acq_32 atomic_add_acq_int 486 #define atomic_add_rel_32 atomic_add_rel_int 487 #define atomic_subtract_32 atomic_subtract_int 488 #define atomic_subtract_acq_32 atomic_subtract_acq_int 489 #define atomic_subtract_rel_32 atomic_subtract_rel_int 490 #define atomic_load_acq_32 atomic_load_acq_int 491 #define atomic_store_rel_32 atomic_store_rel_int 492 #define atomic_cmpset_32 atomic_cmpset_int 493 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int 494 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int 495 #define atomic_swap_32 atomic_swap_int 496 #define atomic_readandclear_32 atomic_readandclear_int 497 #define atomic_fetchadd_32 atomic_fetchadd_int 498 #define atomic_testandset_32 atomic_testandset_int 499 500 /* Operations on 64-bit quad words. */ 501 #define atomic_set_64 atomic_set_long 502 #define atomic_set_acq_64 atomic_set_acq_long 503 #define atomic_set_rel_64 atomic_set_rel_long 504 #define atomic_clear_64 atomic_clear_long 505 #define atomic_clear_acq_64 atomic_clear_acq_long 506 #define atomic_clear_rel_64 atomic_clear_rel_long 507 #define atomic_add_64 atomic_add_long 508 #define atomic_add_acq_64 atomic_add_acq_long 509 #define atomic_add_rel_64 atomic_add_rel_long 510 #define atomic_subtract_64 atomic_subtract_long 511 #define atomic_subtract_acq_64 atomic_subtract_acq_long 512 #define atomic_subtract_rel_64 atomic_subtract_rel_long 513 #define atomic_load_acq_64 atomic_load_acq_long 514 #define atomic_store_rel_64 atomic_store_rel_long 515 #define atomic_cmpset_64 atomic_cmpset_long 516 #define atomic_cmpset_acq_64 atomic_cmpset_acq_long 517 #define atomic_cmpset_rel_64 atomic_cmpset_rel_long 518 #define atomic_swap_64 atomic_swap_long 519 #define atomic_readandclear_64 atomic_readandclear_long 520 #define atomic_testandset_64 atomic_testandset_long 521 522 /* Operations on pointers. */ 523 #define atomic_set_ptr atomic_set_long 524 #define atomic_set_acq_ptr atomic_set_acq_long 525 #define atomic_set_rel_ptr atomic_set_rel_long 526 #define atomic_clear_ptr atomic_clear_long 527 #define atomic_clear_acq_ptr atomic_clear_acq_long 528 #define atomic_clear_rel_ptr atomic_clear_rel_long 529 #define atomic_add_ptr atomic_add_long 530 #define atomic_add_acq_ptr atomic_add_acq_long 531 #define atomic_add_rel_ptr atomic_add_rel_long 532 #define atomic_subtract_ptr atomic_subtract_long 533 #define atomic_subtract_acq_ptr atomic_subtract_acq_long 534 #define atomic_subtract_rel_ptr atomic_subtract_rel_long 535 #define atomic_load_acq_ptr atomic_load_acq_long 536 #define atomic_store_rel_ptr atomic_store_rel_long 537 #define atomic_cmpset_ptr atomic_cmpset_long 538 #define atomic_cmpset_acq_ptr atomic_cmpset_acq_long 539 #define atomic_cmpset_rel_ptr atomic_cmpset_rel_long 540 #define atomic_swap_ptr atomic_swap_long 541 #define atomic_readandclear_ptr atomic_readandclear_long 542 543 #endif /* !WANT_FUNCTIONS */ 544 545 #endif /* !_MACHINE_ATOMIC_H_ */ 546