atomic.h revision 197803
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 197803 2009-10-06 13:45:49Z attilio $ 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) \ 76void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v); \ 77void atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 78 79int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src); 80int atomic_cmpset_barr_int(volatile u_int *dst, u_int exp, u_int src); 81u_int atomic_fetchadd_int(volatile u_int *p, u_int v); 82 83#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 84u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 85void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 86 87#else /* !KLD_MODULE && __GNUCLIKE_ASM */ 88 89/* 90 * For userland, always use lock prefixes so that the binaries will run 91 * on both SMP and !SMP systems. 92 */ 93#if defined(SMP) || !defined(_KERNEL) 94#define MPLOCKED "lock ; " 95#else 96#define MPLOCKED 97#endif 98 99/* 100 * The assembly is volatilized to avoid code chunk removal by the compiler. 101 * GCC aggressively reorders operations and memory clobbering is necessary 102 * in order to avoid that for memory barriers. 103 */ 104#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 105static __inline void \ 106atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 107{ \ 108 __asm __volatile(MPLOCKED OP \ 109 : "=m" (*p) \ 110 : CONS (V), "m" (*p)); \ 111} \ 112 \ 113static __inline void \ 114atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 115{ \ 116 __asm __volatile(MPLOCKED OP \ 117 : "=m" (*p) \ 118 : CONS (V), "m" (*p) \ 119 : "memory"); \ 120} \ 121struct __hack 122 123/* 124 * Atomic compare and set, used by the mutex functions 125 * 126 * if (*dst == exp) *dst = src (all 32 bit words) 127 * 128 * Returns 0 on failure, non-zero on success 129 */ 130 131#ifdef CPU_DISABLE_CMPXCHG 132 133static __inline int 134atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 135{ 136 u_char res; 137 138 __asm __volatile( 139 " pushfl ; " 140 " cli ; " 141 " cmpl %3,%4 ; " 142 " jne 1f ; " 143 " movl %2,%1 ; " 144 "1: " 145 " sete %0 ; " 146 " popfl ; " 147 "# atomic_cmpset_int" 148 : "=q" (res), /* 0 */ 149 "=m" (*dst) /* 1 */ 150 : "r" (src), /* 2 */ 151 "r" (exp), /* 3 */ 152 "m" (*dst) /* 4 */ 153 : "memory"); 154 155 return (res); 156} 157 158#else /* !CPU_DISABLE_CMPXCHG */ 159 160static __inline int 161atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 162{ 163 u_char res; 164 165 __asm __volatile( 166 " " MPLOCKED " " 167 " cmpxchgl %2,%1 ; " 168 " sete %0 ; " 169 "1: " 170 "# atomic_cmpset_int" 171 : "=a" (res), /* 0 */ 172 "=m" (*dst) /* 1 */ 173 : "r" (src), /* 2 */ 174 "a" (exp), /* 3 */ 175 "m" (*dst) /* 4 */ 176 : "memory"); 177 178 return (res); 179} 180 181#endif /* CPU_DISABLE_CMPXCHG */ 182 183#define atomic_cmpset_barr_int atomic_cmpset_int 184 185/* 186 * Atomically add the value of v to the integer pointed to by p and return 187 * the previous value of *p. 188 */ 189static __inline u_int 190atomic_fetchadd_int(volatile u_int *p, u_int v) 191{ 192 193 __asm __volatile( 194 " " MPLOCKED " " 195 " xaddl %0, %1 ; " 196 "# atomic_fetchadd_int" 197 : "+r" (v), /* 0 (result) */ 198 "=m" (*p) /* 1 */ 199 : "m" (*p)); /* 2 */ 200 201 return (v); 202} 203 204#if defined(_KERNEL) && !defined(SMP) 205 206/* 207 * We assume that a = b will do atomic loads and stores. However, on a 208 * PentiumPro or higher, reads may pass writes, so for that case we have 209 * to use a serializing instruction (i.e. with LOCK) to do the load in 210 * SMP kernels. For UP kernels, however, the cache of the single processor 211 * is always consistent, so we only need to take care of compiler. 212 */ 213#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 214static __inline u_##TYPE \ 215atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 216{ \ 217 u_##TYPE tmp; \ 218 \ 219 tmp = *p; \ 220 __asm __volatile("" : : : "memory"); \ 221 return (tmp); \ 222} \ 223 \ 224static __inline void \ 225atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 226{ \ 227 __asm __volatile("" : : : "memory"); \ 228 *p = v; \ 229} \ 230struct __hack 231 232#else /* !(_KERNEL && !SMP) */ 233 234#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 235static __inline u_##TYPE \ 236atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 237{ \ 238 u_##TYPE res; \ 239 \ 240 __asm __volatile(MPLOCKED LOP \ 241 : "=a" (res), /* 0 */ \ 242 "=m" (*p) /* 1 */ \ 243 : "m" (*p) /* 2 */ \ 244 : "memory"); \ 245 \ 246 return (res); \ 247} \ 248 \ 249/* \ 250 * The XCHG instruction asserts LOCK automagically. \ 251 */ \ 252static __inline void \ 253atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 254{ \ 255 __asm __volatile(SOP \ 256 : "=m" (*p), /* 0 */ \ 257 "+r" (v) /* 1 */ \ 258 : "m" (*p) /* 2 */ \ 259 : "memory"); \ 260} \ 261struct __hack 262 263#endif /* _KERNEL && !SMP */ 264 265#endif /* KLD_MODULE || !__GNUCLIKE_ASM */ 266 267ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 268ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 269ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 270ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 271 272ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 273ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 274ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 275ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 276 277ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 278ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 279ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 280ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 281 282ATOMIC_ASM(set, long, "orl %1,%0", "ir", v); 283ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v); 284ATOMIC_ASM(add, long, "addl %1,%0", "ir", v); 285ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v); 286 287ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 288ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 289ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 290ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0"); 291 292#undef ATOMIC_ASM 293#undef ATOMIC_STORE_LOAD 294 295#ifndef WANT_FUNCTIONS 296 297static __inline int 298atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src) 299{ 300 301 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 302 (u_int)src)); 303} 304 305static __inline int 306atomic_cmpset_barr_long(volatile u_long *dst, u_long exp, u_long src) 307{ 308 309 return (atomic_cmpset_barr_int((volatile u_int *)dst, (u_int)exp, 310 (u_int)src)); 311} 312 313static __inline u_long 314atomic_fetchadd_long(volatile u_long *p, u_long v) 315{ 316 317 return (atomic_fetchadd_int((volatile u_int *)p, (u_int)v)); 318} 319 320/* Read the current value and store a zero in the destination. */ 321#ifdef __GNUCLIKE_ASM 322 323static __inline u_int 324atomic_readandclear_int(volatile u_int *addr) 325{ 326 u_int res; 327 328 res = 0; 329 __asm __volatile( 330 " xchgl %1,%0 ; " 331 "# atomic_readandclear_int" 332 : "+r" (res), /* 0 */ 333 "=m" (*addr) /* 1 */ 334 : "m" (*addr)); 335 336 return (res); 337} 338 339static __inline u_long 340atomic_readandclear_long(volatile u_long *addr) 341{ 342 u_long res; 343 344 res = 0; 345 __asm __volatile( 346 " xchgl %1,%0 ; " 347 "# atomic_readandclear_long" 348 : "+r" (res), /* 0 */ 349 "=m" (*addr) /* 1 */ 350 : "m" (*addr)); 351 352 return (res); 353} 354 355#else /* !__GNUCLIKE_ASM */ 356 357u_int atomic_readandclear_int(volatile u_int *addr); 358u_long atomic_readandclear_long(volatile u_long *addr); 359 360#endif /* __GNUCLIKE_ASM */ 361 362#define atomic_set_acq_char atomic_set_barr_char 363#define atomic_set_rel_char atomic_set_barr_char 364#define atomic_clear_acq_char atomic_clear_barr_char 365#define atomic_clear_rel_char atomic_clear_barr_char 366#define atomic_add_acq_char atomic_add_barr_char 367#define atomic_add_rel_char atomic_add_barr_char 368#define atomic_subtract_acq_char atomic_subtract_barr_char 369#define atomic_subtract_rel_char atomic_subtract_barr_char 370 371#define atomic_set_acq_short atomic_set_barr_short 372#define atomic_set_rel_short atomic_set_barr_short 373#define atomic_clear_acq_short atomic_clear_barr_short 374#define atomic_clear_rel_short atomic_clear_barr_short 375#define atomic_add_acq_short atomic_add_barr_short 376#define atomic_add_rel_short atomic_add_barr_short 377#define atomic_subtract_acq_short atomic_subtract_barr_short 378#define atomic_subtract_rel_short atomic_subtract_barr_short 379 380#define atomic_set_acq_int atomic_set_barr_int 381#define atomic_set_rel_int atomic_set_barr_int 382#define atomic_clear_acq_int atomic_clear_barr_int 383#define atomic_clear_rel_int atomic_clear_barr_int 384#define atomic_add_acq_int atomic_add_barr_int 385#define atomic_add_rel_int atomic_add_barr_int 386#define atomic_subtract_acq_int atomic_subtract_barr_int 387#define atomic_subtract_rel_int atomic_subtract_barr_int 388#define atomic_cmpset_acq_int atomic_cmpset_barr_int 389#define atomic_cmpset_rel_int atomic_cmpset_barr_int 390 391#define atomic_set_acq_long atomic_set_barr_long 392#define atomic_set_rel_long atomic_set_barr_long 393#define atomic_clear_acq_long atomic_clear_barr_long 394#define atomic_clear_rel_long atomic_clear_barr_long 395#define atomic_add_acq_long atomic_add_barr_long 396#define atomic_add_rel_long atomic_add_barr_long 397#define atomic_subtract_acq_long atomic_subtract_barr_long 398#define atomic_subtract_rel_long atomic_subtract_barr_long 399#define atomic_cmpset_acq_long atomic_cmpset_barr_long 400#define atomic_cmpset_rel_long atomic_cmpset_barr_long 401 402/* Operations on 8-bit bytes. */ 403#define atomic_set_8 atomic_set_char 404#define atomic_set_acq_8 atomic_set_acq_char 405#define atomic_set_rel_8 atomic_set_rel_char 406#define atomic_clear_8 atomic_clear_char 407#define atomic_clear_acq_8 atomic_clear_acq_char 408#define atomic_clear_rel_8 atomic_clear_rel_char 409#define atomic_add_8 atomic_add_char 410#define atomic_add_acq_8 atomic_add_acq_char 411#define atomic_add_rel_8 atomic_add_rel_char 412#define atomic_subtract_8 atomic_subtract_char 413#define atomic_subtract_acq_8 atomic_subtract_acq_char 414#define atomic_subtract_rel_8 atomic_subtract_rel_char 415#define atomic_load_acq_8 atomic_load_acq_char 416#define atomic_store_rel_8 atomic_store_rel_char 417 418/* Operations on 16-bit words. */ 419#define atomic_set_16 atomic_set_short 420#define atomic_set_acq_16 atomic_set_acq_short 421#define atomic_set_rel_16 atomic_set_rel_short 422#define atomic_clear_16 atomic_clear_short 423#define atomic_clear_acq_16 atomic_clear_acq_short 424#define atomic_clear_rel_16 atomic_clear_rel_short 425#define atomic_add_16 atomic_add_short 426#define atomic_add_acq_16 atomic_add_acq_short 427#define atomic_add_rel_16 atomic_add_rel_short 428#define atomic_subtract_16 atomic_subtract_short 429#define atomic_subtract_acq_16 atomic_subtract_acq_short 430#define atomic_subtract_rel_16 atomic_subtract_rel_short 431#define atomic_load_acq_16 atomic_load_acq_short 432#define atomic_store_rel_16 atomic_store_rel_short 433 434/* Operations on 32-bit double words. */ 435#define atomic_set_32 atomic_set_int 436#define atomic_set_acq_32 atomic_set_acq_int 437#define atomic_set_rel_32 atomic_set_rel_int 438#define atomic_clear_32 atomic_clear_int 439#define atomic_clear_acq_32 atomic_clear_acq_int 440#define atomic_clear_rel_32 atomic_clear_rel_int 441#define atomic_add_32 atomic_add_int 442#define atomic_add_acq_32 atomic_add_acq_int 443#define atomic_add_rel_32 atomic_add_rel_int 444#define atomic_subtract_32 atomic_subtract_int 445#define atomic_subtract_acq_32 atomic_subtract_acq_int 446#define atomic_subtract_rel_32 atomic_subtract_rel_int 447#define atomic_load_acq_32 atomic_load_acq_int 448#define atomic_store_rel_32 atomic_store_rel_int 449#define atomic_cmpset_32 atomic_cmpset_int 450#define atomic_cmpset_acq_32 atomic_cmpset_acq_int 451#define atomic_cmpset_rel_32 atomic_cmpset_rel_int 452#define atomic_readandclear_32 atomic_readandclear_int 453#define atomic_fetchadd_32 atomic_fetchadd_int 454 455/* Operations on pointers. */ 456#define atomic_set_ptr(p, v) \ 457 atomic_set_int((volatile u_int *)(p), (u_int)(v)) 458#define atomic_set_acq_ptr(p, v) \ 459 atomic_set_acq_int((volatile u_int *)(p), (u_int)(v)) 460#define atomic_set_rel_ptr(p, v) \ 461 atomic_set_rel_int((volatile u_int *)(p), (u_int)(v)) 462#define atomic_clear_ptr(p, v) \ 463 atomic_clear_int((volatile u_int *)(p), (u_int)(v)) 464#define atomic_clear_acq_ptr(p, v) \ 465 atomic_clear_acq_int((volatile u_int *)(p), (u_int)(v)) 466#define atomic_clear_rel_ptr(p, v) \ 467 atomic_clear_rel_int((volatile u_int *)(p), (u_int)(v)) 468#define atomic_add_ptr(p, v) \ 469 atomic_add_int((volatile u_int *)(p), (u_int)(v)) 470#define atomic_add_acq_ptr(p, v) \ 471 atomic_add_acq_int((volatile u_int *)(p), (u_int)(v)) 472#define atomic_add_rel_ptr(p, v) \ 473 atomic_add_rel_int((volatile u_int *)(p), (u_int)(v)) 474#define atomic_subtract_ptr(p, v) \ 475 atomic_subtract_int((volatile u_int *)(p), (u_int)(v)) 476#define atomic_subtract_acq_ptr(p, v) \ 477 atomic_subtract_acq_int((volatile u_int *)(p), (u_int)(v)) 478#define atomic_subtract_rel_ptr(p, v) \ 479 atomic_subtract_rel_int((volatile u_int *)(p), (u_int)(v)) 480#define atomic_load_acq_ptr(p) \ 481 atomic_load_acq_int((volatile u_int *)(p)) 482#define atomic_store_rel_ptr(p, v) \ 483 atomic_store_rel_int((volatile u_int *)(p), (v)) 484#define atomic_cmpset_ptr(dst, old, new) \ 485 atomic_cmpset_int((volatile u_int *)(dst), (u_int)(old), (u_int)(new)) 486#define atomic_cmpset_acq_ptr(dst, old, new) \ 487 atomic_cmpset_acq_int((volatile u_int *)(dst), (u_int)(old), \ 488 (u_int)(new)) 489#define atomic_cmpset_rel_ptr(dst, old, new) \ 490 atomic_cmpset_rel_int((volatile u_int *)(dst), (u_int)(old), \ 491 (u_int)(new)) 492#define atomic_readandclear_ptr(p) \ 493 atomic_readandclear_int((volatile u_int *)(p)) 494 495#endif /* !WANT_FUNCTIONS */ 496 497#endif /* !_MACHINE_ATOMIC_H_ */ 498