atomic.h revision 165572
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/amd64/include/atomic.h 165572 2006-12-27 20:26:00Z bde $ 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/* 36 * Various simple arithmetic on memory which is atomic in the presence 37 * of interrupts and multiple processors. 38 * 39 * atomic_set_char(P, V) (*(u_char*)(P) |= (V)) 40 * atomic_clear_char(P, V) (*(u_char*)(P) &= ~(V)) 41 * atomic_add_char(P, V) (*(u_char*)(P) += (V)) 42 * atomic_subtract_char(P, V) (*(u_char*)(P) -= (V)) 43 * 44 * atomic_set_short(P, V) (*(u_short*)(P) |= (V)) 45 * atomic_clear_short(P, V) (*(u_short*)(P) &= ~(V)) 46 * atomic_add_short(P, V) (*(u_short*)(P) += (V)) 47 * atomic_subtract_short(P, V) (*(u_short*)(P) -= (V)) 48 * 49 * atomic_set_int(P, V) (*(u_int*)(P) |= (V)) 50 * atomic_clear_int(P, V) (*(u_int*)(P) &= ~(V)) 51 * atomic_add_int(P, V) (*(u_int*)(P) += (V)) 52 * atomic_subtract_int(P, V) (*(u_int*)(P) -= (V)) 53 * atomic_readandclear_int(P) (return *(u_int*)P; *(u_int*)P = 0;) 54 * 55 * atomic_set_long(P, V) (*(u_long*)(P) |= (V)) 56 * atomic_clear_long(P, V) (*(u_long*)(P) &= ~(V)) 57 * atomic_add_long(P, V) (*(u_long*)(P) += (V)) 58 * atomic_subtract_long(P, V) (*(u_long*)(P) -= (V)) 59 * atomic_readandclear_long(P) (return *(u_long*)P; *(u_long*)P = 0;) 60 */ 61 62/* 63 * The above functions are expanded inline in the statically-linked 64 * kernel. Lock prefixes are generated if an SMP kernel is being 65 * built. 66 * 67 * Kernel modules call real functions which are built into the kernel. 68 * This allows kernel modules to be portable between UP and SMP systems. 69 */ 70#if defined(KLD_MODULE) || !(defined(__GNUCLIKE_ASM) && defined(__CC_SUPPORTS___INLINE)) 71#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 72void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 73 74int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src); 75int atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src); 76u_int atomic_fetchadd_int(volatile u_int *p, u_int v); 77 78#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 79u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 80void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 81 82#else /* !KLD_MODULE && __GNUCLIKE_ASM && __CC_SUPPORTS___INLINE */ 83 84/* 85 * For userland, assume the SMP case and use lock prefixes so that 86 * the binaries will run on both types of systems. 87 */ 88#if defined(SMP) || !defined(_KERNEL) 89#define MPLOCKED lock ; 90#else 91#define MPLOCKED 92#endif 93 94/* 95 * The assembly is volatilized to demark potential before-and-after side 96 * effects if an interrupt or SMP collision were to occur. 97 */ 98#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 99static __inline void \ 100atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 101{ \ 102 __asm __volatile(__XSTRING(MPLOCKED) OP \ 103 : "=m" (*p) \ 104 : CONS (V), "m" (*p)); \ 105} \ 106struct __hack 107 108/* 109 * Atomic compare and set, used by the mutex functions 110 * 111 * if (*dst == exp) *dst = src (all 32 bit words) 112 * 113 * Returns 0 on failure, non-zero on success 114 */ 115 116static __inline int 117atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 118{ 119 u_char res; 120 121 __asm __volatile ( 122 " " __XSTRING(MPLOCKED) " " 123 " cmpxchgl %2,%1 ; " 124 " sete %0 ; " 125 "1: " 126 "# atomic_cmpset_int" 127 : "=a" (res), /* 0 */ 128 "=m" (*dst) /* 1 */ 129 : "r" (src), /* 2 */ 130 "a" (exp), /* 3 */ 131 "m" (*dst) /* 4 */ 132 : "memory"); 133 134 return (res); 135} 136 137static __inline int 138atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src) 139{ 140 u_char res; 141 142 __asm __volatile ( 143 " " __XSTRING(MPLOCKED) " " 144 " cmpxchgq %2,%1 ; " 145 " sete %0 ; " 146 "1: " 147 "# atomic_cmpset_long" 148 : "=a" (res), /* 0 */ 149 "=m" (*dst) /* 1 */ 150 : "r" (src), /* 2 */ 151 "a" (exp), /* 3 */ 152 "m" (*dst) /* 4 */ 153 : "memory"); 154 155 return (res); 156} 157 158/* 159 * Atomically add the value of v to the integer pointed to by p and return 160 * the previous value of *p. 161 */ 162static __inline u_int 163atomic_fetchadd_int(volatile u_int *p, u_int v) 164{ 165 166 __asm __volatile ( 167 " " __XSTRING(MPLOCKED) " " 168 " xaddl %0, %1 ; " 169 "# atomic_fetchadd_int" 170 : "+r" (v), /* 0 (result) */ 171 "=m" (*p) /* 1 */ 172 : "m" (*p)); /* 2 */ 173 174 return (v); 175} 176 177#if defined(_KERNEL) && !defined(SMP) 178 179/* 180 * We assume that a = b will do atomic loads and stores. However, on a 181 * PentiumPro or higher, reads may pass writes, so for that case we have 182 * to use a serializing instruction (i.e. with LOCK) to do the load in 183 * SMP kernels. For UP kernels, however, the cache of the single processor 184 * is always consistent, so we don't need any memory barriers. 185 */ 186#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 187static __inline u_##TYPE \ 188atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 189{ \ 190 return (*p); \ 191} \ 192 \ 193static __inline void \ 194atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 195{ \ 196 *p = v; \ 197} \ 198struct __hack 199 200#else /* defined(SMP) */ 201 202#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 203static __inline u_##TYPE \ 204atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 205{ \ 206 u_##TYPE res; \ 207 \ 208 __asm __volatile(__XSTRING(MPLOCKED) LOP \ 209 : "=a" (res), /* 0 (result) */\ 210 "=m" (*p) /* 1 */ \ 211 : "m" (*p) /* 2 */ \ 212 : "memory"); \ 213 \ 214 return (res); \ 215} \ 216 \ 217/* \ 218 * The XCHG instruction asserts LOCK automagically. \ 219 */ \ 220static __inline void \ 221atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 222{ \ 223 __asm __volatile(SOP \ 224 : "=m" (*p), /* 0 */ \ 225 "+r" (v) /* 1 */ \ 226 : "m" (*p)); /* 2 */ \ 227} \ 228struct __hack 229 230#endif /* SMP */ 231 232#endif /* KLD_MODULE || !(__GNUCLIKE_ASM && __CC_SUPPORTS___INLINE) */ 233 234ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 235ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 236ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 237ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 238 239ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 240ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 241ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 242ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 243 244ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 245ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 246ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 247ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 248 249ATOMIC_ASM(set, long, "orq %1,%0", "ir", v); 250ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v); 251ATOMIC_ASM(add, long, "addq %1,%0", "ir", v); 252ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v); 253 254ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 255ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 256ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 257ATOMIC_STORE_LOAD(long, "cmpxchgq %0,%1", "xchgq %1,%0"); 258 259#undef ATOMIC_ASM 260#undef ATOMIC_STORE_LOAD 261 262#if !defined(WANT_FUNCTIONS) 263 264/* Read the current value and store a zero in the destination. */ 265#if defined(__GNUCLIKE_ASM) && defined(__CC_SUPPORTS___INLINE) 266 267static __inline u_int 268atomic_readandclear_int(volatile u_int *addr) 269{ 270 u_int result; 271 272 result = 0; 273 __asm __volatile ( 274 " xchgl %1,%0 ; " 275 "# atomic_readandclear_int" 276 : "+r" (result), /* 0 (result) */ 277 "=m" (*addr) /* 1 (addr) */ 278 : "m" (*addr)); 279 280 return (result); 281} 282 283static __inline u_long 284atomic_readandclear_long(volatile u_long *addr) 285{ 286 u_long result; 287 288 result = 0; 289 __asm __volatile ( 290 " xchgq %1,%0 ; " 291 "# atomic_readandclear_long" 292 : "+r" (result), /* 0 (result) */ 293 "=m" (*addr) /* 1 (addr) */ 294 : "m" (*addr)); 295 296 return (result); 297} 298 299#else /* !(__GNUCLIKE_ASM && __CC_SUPPORTS___INLINE) */ 300 301u_int atomic_readandclear_int(volatile u_int *); 302u_long atomic_readandclear_long(volatile u_long *); 303 304#endif /* __GNUCLIKE_ASM && __CC_SUPPORTS___INLINE */ 305 306/* Acquire and release variants are identical to the normal ones. */ 307#define atomic_set_acq_char atomic_set_char 308#define atomic_set_rel_char atomic_set_char 309#define atomic_clear_acq_char atomic_clear_char 310#define atomic_clear_rel_char atomic_clear_char 311#define atomic_add_acq_char atomic_add_char 312#define atomic_add_rel_char atomic_add_char 313#define atomic_subtract_acq_char atomic_subtract_char 314#define atomic_subtract_rel_char atomic_subtract_char 315 316#define atomic_set_acq_short atomic_set_short 317#define atomic_set_rel_short atomic_set_short 318#define atomic_clear_acq_short atomic_clear_short 319#define atomic_clear_rel_short atomic_clear_short 320#define atomic_add_acq_short atomic_add_short 321#define atomic_add_rel_short atomic_add_short 322#define atomic_subtract_acq_short atomic_subtract_short 323#define atomic_subtract_rel_short atomic_subtract_short 324 325#define atomic_set_acq_int atomic_set_int 326#define atomic_set_rel_int atomic_set_int 327#define atomic_clear_acq_int atomic_clear_int 328#define atomic_clear_rel_int atomic_clear_int 329#define atomic_add_acq_int atomic_add_int 330#define atomic_add_rel_int atomic_add_int 331#define atomic_subtract_acq_int atomic_subtract_int 332#define atomic_subtract_rel_int atomic_subtract_int 333#define atomic_cmpset_acq_int atomic_cmpset_int 334#define atomic_cmpset_rel_int atomic_cmpset_int 335 336#define atomic_set_acq_long atomic_set_long 337#define atomic_set_rel_long atomic_set_long 338#define atomic_clear_acq_long atomic_clear_long 339#define atomic_clear_rel_long atomic_clear_long 340#define atomic_add_acq_long atomic_add_long 341#define atomic_add_rel_long atomic_add_long 342#define atomic_subtract_acq_long atomic_subtract_long 343#define atomic_subtract_rel_long atomic_subtract_long 344#define atomic_cmpset_acq_long atomic_cmpset_long 345#define atomic_cmpset_rel_long atomic_cmpset_long 346 347/* Operations on 8-bit bytes. */ 348#define atomic_set_8 atomic_set_char 349#define atomic_set_acq_8 atomic_set_acq_char 350#define atomic_set_rel_8 atomic_set_rel_char 351#define atomic_clear_8 atomic_clear_char 352#define atomic_clear_acq_8 atomic_clear_acq_char 353#define atomic_clear_rel_8 atomic_clear_rel_char 354#define atomic_add_8 atomic_add_char 355#define atomic_add_acq_8 atomic_add_acq_char 356#define atomic_add_rel_8 atomic_add_rel_char 357#define atomic_subtract_8 atomic_subtract_char 358#define atomic_subtract_acq_8 atomic_subtract_acq_char 359#define atomic_subtract_rel_8 atomic_subtract_rel_char 360#define atomic_load_acq_8 atomic_load_acq_char 361#define atomic_store_rel_8 atomic_store_rel_char 362 363/* Operations on 16-bit words. */ 364#define atomic_set_16 atomic_set_short 365#define atomic_set_acq_16 atomic_set_acq_short 366#define atomic_set_rel_16 atomic_set_rel_short 367#define atomic_clear_16 atomic_clear_short 368#define atomic_clear_acq_16 atomic_clear_acq_short 369#define atomic_clear_rel_16 atomic_clear_rel_short 370#define atomic_add_16 atomic_add_short 371#define atomic_add_acq_16 atomic_add_acq_short 372#define atomic_add_rel_16 atomic_add_rel_short 373#define atomic_subtract_16 atomic_subtract_short 374#define atomic_subtract_acq_16 atomic_subtract_acq_short 375#define atomic_subtract_rel_16 atomic_subtract_rel_short 376#define atomic_load_acq_16 atomic_load_acq_short 377#define atomic_store_rel_16 atomic_store_rel_short 378 379/* Operations on 32-bit double words. */ 380#define atomic_set_32 atomic_set_int 381#define atomic_set_acq_32 atomic_set_acq_int 382#define atomic_set_rel_32 atomic_set_rel_int 383#define atomic_clear_32 atomic_clear_int 384#define atomic_clear_acq_32 atomic_clear_acq_int 385#define atomic_clear_rel_32 atomic_clear_rel_int 386#define atomic_add_32 atomic_add_int 387#define atomic_add_acq_32 atomic_add_acq_int 388#define atomic_add_rel_32 atomic_add_rel_int 389#define atomic_subtract_32 atomic_subtract_int 390#define atomic_subtract_acq_32 atomic_subtract_acq_int 391#define atomic_subtract_rel_32 atomic_subtract_rel_int 392#define atomic_load_acq_32 atomic_load_acq_int 393#define atomic_store_rel_32 atomic_store_rel_int 394#define atomic_cmpset_32 atomic_cmpset_int 395#define atomic_cmpset_acq_32 atomic_cmpset_acq_int 396#define atomic_cmpset_rel_32 atomic_cmpset_rel_int 397#define atomic_readandclear_32 atomic_readandclear_int 398#define atomic_fetchadd_32 atomic_fetchadd_int 399 400/* Operations on 64-bit quad words. */ 401#define atomic_set_64 atomic_set_long 402#define atomic_set_acq_64 atomic_set_acq_long 403#define atomic_set_rel_64 atomic_set_rel_long 404#define atomic_clear_64 atomic_clear_long 405#define atomic_clear_acq_64 atomic_clear_acq_long 406#define atomic_clear_rel_64 atomic_clear_rel_long 407#define atomic_add_64 atomic_add_long 408#define atomic_add_acq_64 atomic_add_acq_long 409#define atomic_add_rel_64 atomic_add_rel_long 410#define atomic_subtract_64 atomic_subtract_long 411#define atomic_subtract_acq_64 atomic_subtract_acq_long 412#define atomic_subtract_rel_64 atomic_subtract_rel_long 413#define atomic_load_acq_64 atomic_load_acq_long 414#define atomic_store_rel_64 atomic_store_rel_long 415#define atomic_cmpset_64 atomic_cmpset_long 416#define atomic_cmpset_acq_64 atomic_cmpset_acq_long 417#define atomic_cmpset_rel_64 atomic_cmpset_rel_long 418#define atomic_readandclear_64 atomic_readandclear_long 419 420/* Operations on pointers. */ 421#define atomic_set_ptr atomic_set_long 422#define atomic_set_acq_ptr atomic_set_acq_long 423#define atomic_set_rel_ptr atomic_set_rel_long 424#define atomic_clear_ptr atomic_clear_long 425#define atomic_clear_acq_ptr atomic_clear_acq_long 426#define atomic_clear_rel_ptr atomic_clear_rel_long 427#define atomic_add_ptr atomic_add_long 428#define atomic_add_acq_ptr atomic_add_acq_long 429#define atomic_add_rel_ptr atomic_add_rel_long 430#define atomic_subtract_ptr atomic_subtract_long 431#define atomic_subtract_acq_ptr atomic_subtract_acq_long 432#define atomic_subtract_rel_ptr atomic_subtract_rel_long 433#define atomic_load_acq_ptr atomic_load_acq_long 434#define atomic_store_rel_ptr atomic_store_rel_long 435#define atomic_cmpset_ptr atomic_cmpset_long 436#define atomic_cmpset_acq_ptr atomic_cmpset_acq_long 437#define atomic_cmpset_rel_ptr atomic_cmpset_rel_long 438#define atomic_readandclear_ptr atomic_readandclear_long 439 440#endif /* !defined(WANT_FUNCTIONS) */ 441#endif /* ! _MACHINE_ATOMIC_H_ */ 442