atomic.h revision 216524
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 216524 2010-12-18 16:41:11Z kib $ 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 expect, u_int src); 80u_int atomic_fetchadd_int(volatile u_int *p, u_int v); 81 82#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 83u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 84void 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) \ 104static __inline void \ 105atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 106{ \ 107 __asm __volatile(MPLOCKED OP \ 108 : "=m" (*p) \ 109 : CONS (V), "m" (*p) \ 110 : "cc"); \ 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", "cc"); \ 120} \ 121struct __hack 122 123/* 124 * Atomic compare and set, used by the mutex functions 125 * 126 * if (*dst == expect) *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 expect, 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" (expect), /* 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 expect, 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" (expect), /* 3 */ 175 "m" (*dst) /* 4 */ 176 : "memory", "cc"); 177 178 return (res); 179} 180 181#endif /* CPU_DISABLE_CMPXCHG */ 182 183/* 184 * Atomically add the value of v to the integer pointed to by p and return 185 * the previous value of *p. 186 */ 187static __inline u_int 188atomic_fetchadd_int(volatile u_int *p, u_int v) 189{ 190 191 __asm __volatile( 192 " " MPLOCKED " " 193 " xaddl %0, %1 ; " 194 "# atomic_fetchadd_int" 195 : "+r" (v), /* 0 (result) */ 196 "=m" (*p) /* 1 */ 197 : "m" (*p) /* 2 */ 198 : "cc"); 199 return (v); 200} 201 202#if defined(_KERNEL) && !defined(SMP) 203 204/* 205 * We assume that a = b will do atomic loads and stores. However, on a 206 * PentiumPro or higher, reads may pass writes, so for that case we have 207 * to use a serializing instruction (i.e. with LOCK) to do the load in 208 * SMP kernels. For UP kernels, however, the cache of the single processor 209 * is always consistent, so we only need to take care of compiler. 210 */ 211#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 212static __inline u_##TYPE \ 213atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 214{ \ 215 u_##TYPE tmp; \ 216 \ 217 tmp = *p; \ 218 __asm __volatile("" : : : "memory"); \ 219 return (tmp); \ 220} \ 221 \ 222static __inline void \ 223atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 224{ \ 225 __asm __volatile("" : : : "memory"); \ 226 *p = v; \ 227} \ 228struct __hack 229 230#else /* !(_KERNEL && !SMP) */ 231 232#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 233static __inline u_##TYPE \ 234atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 235{ \ 236 u_##TYPE res; \ 237 \ 238 __asm __volatile(MPLOCKED LOP \ 239 : "=a" (res), /* 0 */ \ 240 "=m" (*p) /* 1 */ \ 241 : "m" (*p) /* 2 */ \ 242 : "memory", "cc"); \ 243 \ 244 return (res); \ 245} \ 246 \ 247/* \ 248 * The XCHG instruction asserts LOCK automagically. \ 249 */ \ 250static __inline void \ 251atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 252{ \ 253 __asm __volatile(SOP \ 254 : "=m" (*p), /* 0 */ \ 255 "+r" (v) /* 1 */ \ 256 : "m" (*p) /* 2 */ \ 257 : "memory"); \ 258} \ 259struct __hack 260 261#endif /* _KERNEL && !SMP */ 262 263#endif /* KLD_MODULE || !__GNUCLIKE_ASM */ 264 265ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 266ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 267ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 268ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 269 270ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 271ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 272ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 273ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 274 275ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 276ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 277ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 278ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 279 280ATOMIC_ASM(set, long, "orl %1,%0", "ir", v); 281ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v); 282ATOMIC_ASM(add, long, "addl %1,%0", "ir", v); 283ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v); 284 285ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 286ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 287ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 288ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0"); 289 290#undef ATOMIC_ASM 291#undef ATOMIC_STORE_LOAD 292 293#ifndef WANT_FUNCTIONS 294 295static __inline int 296atomic_cmpset_long(volatile u_long *dst, u_long expect, u_long src) 297{ 298 299 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)expect, 300 (u_int)src)); 301} 302 303static __inline u_long 304atomic_fetchadd_long(volatile u_long *p, u_long v) 305{ 306 307 return (atomic_fetchadd_int((volatile u_int *)p, (u_int)v)); 308} 309 310/* Read the current value and store a zero in the destination. */ 311#ifdef __GNUCLIKE_ASM 312 313static __inline u_int 314atomic_readandclear_int(volatile u_int *addr) 315{ 316 u_int res; 317 318 res = 0; 319 __asm __volatile( 320 " xchgl %1,%0 ; " 321 "# atomic_readandclear_int" 322 : "+r" (res), /* 0 */ 323 "=m" (*addr) /* 1 */ 324 : "m" (*addr)); 325 326 return (res); 327} 328 329static __inline u_long 330atomic_readandclear_long(volatile u_long *addr) 331{ 332 u_long res; 333 334 res = 0; 335 __asm __volatile( 336 " xchgl %1,%0 ; " 337 "# atomic_readandclear_long" 338 : "+r" (res), /* 0 */ 339 "=m" (*addr) /* 1 */ 340 : "m" (*addr)); 341 342 return (res); 343} 344 345#else /* !__GNUCLIKE_ASM */ 346 347u_int atomic_readandclear_int(volatile u_int *addr); 348u_long atomic_readandclear_long(volatile u_long *addr); 349 350#endif /* __GNUCLIKE_ASM */ 351 352#define atomic_set_acq_char atomic_set_barr_char 353#define atomic_set_rel_char atomic_set_barr_char 354#define atomic_clear_acq_char atomic_clear_barr_char 355#define atomic_clear_rel_char atomic_clear_barr_char 356#define atomic_add_acq_char atomic_add_barr_char 357#define atomic_add_rel_char atomic_add_barr_char 358#define atomic_subtract_acq_char atomic_subtract_barr_char 359#define atomic_subtract_rel_char atomic_subtract_barr_char 360 361#define atomic_set_acq_short atomic_set_barr_short 362#define atomic_set_rel_short atomic_set_barr_short 363#define atomic_clear_acq_short atomic_clear_barr_short 364#define atomic_clear_rel_short atomic_clear_barr_short 365#define atomic_add_acq_short atomic_add_barr_short 366#define atomic_add_rel_short atomic_add_barr_short 367#define atomic_subtract_acq_short atomic_subtract_barr_short 368#define atomic_subtract_rel_short atomic_subtract_barr_short 369 370#define atomic_set_acq_int atomic_set_barr_int 371#define atomic_set_rel_int atomic_set_barr_int 372#define atomic_clear_acq_int atomic_clear_barr_int 373#define atomic_clear_rel_int atomic_clear_barr_int 374#define atomic_add_acq_int atomic_add_barr_int 375#define atomic_add_rel_int atomic_add_barr_int 376#define atomic_subtract_acq_int atomic_subtract_barr_int 377#define atomic_subtract_rel_int atomic_subtract_barr_int 378#define atomic_cmpset_acq_int atomic_cmpset_int 379#define atomic_cmpset_rel_int atomic_cmpset_int 380 381#define atomic_set_acq_long atomic_set_barr_long 382#define atomic_set_rel_long atomic_set_barr_long 383#define atomic_clear_acq_long atomic_clear_barr_long 384#define atomic_clear_rel_long atomic_clear_barr_long 385#define atomic_add_acq_long atomic_add_barr_long 386#define atomic_add_rel_long atomic_add_barr_long 387#define atomic_subtract_acq_long atomic_subtract_barr_long 388#define atomic_subtract_rel_long atomic_subtract_barr_long 389#define atomic_cmpset_acq_long atomic_cmpset_long 390#define atomic_cmpset_rel_long atomic_cmpset_long 391 392/* Operations on 8-bit bytes. */ 393#define atomic_set_8 atomic_set_char 394#define atomic_set_acq_8 atomic_set_acq_char 395#define atomic_set_rel_8 atomic_set_rel_char 396#define atomic_clear_8 atomic_clear_char 397#define atomic_clear_acq_8 atomic_clear_acq_char 398#define atomic_clear_rel_8 atomic_clear_rel_char 399#define atomic_add_8 atomic_add_char 400#define atomic_add_acq_8 atomic_add_acq_char 401#define atomic_add_rel_8 atomic_add_rel_char 402#define atomic_subtract_8 atomic_subtract_char 403#define atomic_subtract_acq_8 atomic_subtract_acq_char 404#define atomic_subtract_rel_8 atomic_subtract_rel_char 405#define atomic_load_acq_8 atomic_load_acq_char 406#define atomic_store_rel_8 atomic_store_rel_char 407 408/* Operations on 16-bit words. */ 409#define atomic_set_16 atomic_set_short 410#define atomic_set_acq_16 atomic_set_acq_short 411#define atomic_set_rel_16 atomic_set_rel_short 412#define atomic_clear_16 atomic_clear_short 413#define atomic_clear_acq_16 atomic_clear_acq_short 414#define atomic_clear_rel_16 atomic_clear_rel_short 415#define atomic_add_16 atomic_add_short 416#define atomic_add_acq_16 atomic_add_acq_short 417#define atomic_add_rel_16 atomic_add_rel_short 418#define atomic_subtract_16 atomic_subtract_short 419#define atomic_subtract_acq_16 atomic_subtract_acq_short 420#define atomic_subtract_rel_16 atomic_subtract_rel_short 421#define atomic_load_acq_16 atomic_load_acq_short 422#define atomic_store_rel_16 atomic_store_rel_short 423 424/* Operations on 32-bit double words. */ 425#define atomic_set_32 atomic_set_int 426#define atomic_set_acq_32 atomic_set_acq_int 427#define atomic_set_rel_32 atomic_set_rel_int 428#define atomic_clear_32 atomic_clear_int 429#define atomic_clear_acq_32 atomic_clear_acq_int 430#define atomic_clear_rel_32 atomic_clear_rel_int 431#define atomic_add_32 atomic_add_int 432#define atomic_add_acq_32 atomic_add_acq_int 433#define atomic_add_rel_32 atomic_add_rel_int 434#define atomic_subtract_32 atomic_subtract_int 435#define atomic_subtract_acq_32 atomic_subtract_acq_int 436#define atomic_subtract_rel_32 atomic_subtract_rel_int 437#define atomic_load_acq_32 atomic_load_acq_int 438#define atomic_store_rel_32 atomic_store_rel_int 439#define atomic_cmpset_32 atomic_cmpset_int 440#define atomic_cmpset_acq_32 atomic_cmpset_acq_int 441#define atomic_cmpset_rel_32 atomic_cmpset_rel_int 442#define atomic_readandclear_32 atomic_readandclear_int 443#define atomic_fetchadd_32 atomic_fetchadd_int 444 445/* Operations on pointers. */ 446#define atomic_set_ptr(p, v) \ 447 atomic_set_int((volatile u_int *)(p), (u_int)(v)) 448#define atomic_set_acq_ptr(p, v) \ 449 atomic_set_acq_int((volatile u_int *)(p), (u_int)(v)) 450#define atomic_set_rel_ptr(p, v) \ 451 atomic_set_rel_int((volatile u_int *)(p), (u_int)(v)) 452#define atomic_clear_ptr(p, v) \ 453 atomic_clear_int((volatile u_int *)(p), (u_int)(v)) 454#define atomic_clear_acq_ptr(p, v) \ 455 atomic_clear_acq_int((volatile u_int *)(p), (u_int)(v)) 456#define atomic_clear_rel_ptr(p, v) \ 457 atomic_clear_rel_int((volatile u_int *)(p), (u_int)(v)) 458#define atomic_add_ptr(p, v) \ 459 atomic_add_int((volatile u_int *)(p), (u_int)(v)) 460#define atomic_add_acq_ptr(p, v) \ 461 atomic_add_acq_int((volatile u_int *)(p), (u_int)(v)) 462#define atomic_add_rel_ptr(p, v) \ 463 atomic_add_rel_int((volatile u_int *)(p), (u_int)(v)) 464#define atomic_subtract_ptr(p, v) \ 465 atomic_subtract_int((volatile u_int *)(p), (u_int)(v)) 466#define atomic_subtract_acq_ptr(p, v) \ 467 atomic_subtract_acq_int((volatile u_int *)(p), (u_int)(v)) 468#define atomic_subtract_rel_ptr(p, v) \ 469 atomic_subtract_rel_int((volatile u_int *)(p), (u_int)(v)) 470#define atomic_load_acq_ptr(p) \ 471 atomic_load_acq_int((volatile u_int *)(p)) 472#define atomic_store_rel_ptr(p, v) \ 473 atomic_store_rel_int((volatile u_int *)(p), (v)) 474#define atomic_cmpset_ptr(dst, old, new) \ 475 atomic_cmpset_int((volatile u_int *)(dst), (u_int)(old), (u_int)(new)) 476#define atomic_cmpset_acq_ptr(dst, old, new) \ 477 atomic_cmpset_acq_int((volatile u_int *)(dst), (u_int)(old), \ 478 (u_int)(new)) 479#define atomic_cmpset_rel_ptr(dst, old, new) \ 480 atomic_cmpset_rel_int((volatile u_int *)(dst), (u_int)(old), \ 481 (u_int)(new)) 482#define atomic_readandclear_ptr(p) \ 483 atomic_readandclear_int((volatile u_int *)(p)) 484 485#endif /* !WANT_FUNCTIONS */ 486 487#endif /* !_MACHINE_ATOMIC_H_ */ 488