atomic.h revision 147855
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 147855 2005-07-09 12:38:53Z 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/* 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) 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); 75 76#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 77u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 78void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 79 80#else /* !KLD_MODULE && __GNUCLIKE_ASM */ 81 82/* 83 * For userland, assume the SMP case and use lock prefixes so that 84 * the binaries will run on both types of systems. 85 */ 86#if defined(SMP) || !defined(_KERNEL) 87#define MPLOCKED lock ; 88#else 89#define MPLOCKED 90#endif 91 92/* 93 * The assembly is volatilized to demark potential before-and-after side 94 * effects if an interrupt or SMP collision were to occur. 95 */ 96#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 97static __inline void \ 98atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 99{ \ 100 __asm __volatile(__XSTRING(MPLOCKED) OP \ 101 : "+m" (*p) \ 102 : CONS (V)); \ 103} \ 104struct __hack 105 106/* 107 * Atomic compare and set, used by the mutex functions 108 * 109 * if (*dst == exp) *dst = src (all 32 bit words) 110 * 111 * Returns 0 on failure, non-zero on success 112 */ 113 114#if defined(CPU_DISABLE_CMPXCHG) 115 116static __inline int 117atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 118{ 119 int res = exp; 120 121 __asm __volatile( 122 " pushfl ; " 123 " cli ; " 124 " cmpl %0,%2 ; " 125 " jne 1f ; " 126 " movl %1,%2 ; " 127 "1: " 128 " sete %%al; " 129 " movzbl %%al,%0 ; " 130 " popfl ; " 131 "# atomic_cmpset_int" 132 : "+a" (res) /* 0 (result) */ 133 : "r" (src), /* 1 */ 134 "m" (*(dst)) /* 2 */ 135 : "memory"); 136 137 return (res); 138} 139 140#else /* defined(CPU_DISABLE_CMPXCHG) */ 141 142static __inline int 143atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 144{ 145 int res = exp; 146 147 __asm __volatile ( 148 " " __XSTRING(MPLOCKED) " " 149 " cmpxchgl %1,%2 ; " 150 " setz %%al ; " 151 " movzbl %%al,%0 ; " 152 "1: " 153 "# atomic_cmpset_int" 154 : "+a" (res) /* 0 (result) */ 155 : "r" (src), /* 1 */ 156 "m" (*(dst)) /* 2 */ 157 : "memory"); 158 159 return (res); 160} 161 162#endif /* defined(CPU_DISABLE_CMPXCHG) */ 163 164#if defined(_KERNEL) && !defined(SMP) 165 166/* 167 * We assume that a = b will do atomic loads and stores. However, on a 168 * PentiumPro or higher, reads may pass writes, so for that case we have 169 * to use a serializing instruction (i.e. with LOCK) to do the load in 170 * SMP kernels. For UP kernels, however, the cache of the single processor 171 * is always consistent, so we don't need any memory barriers. 172 */ 173#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 174static __inline u_##TYPE \ 175atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 176{ \ 177 return (*p); \ 178} \ 179 \ 180static __inline void \ 181atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 182{ \ 183 *p = v; \ 184} \ 185struct __hack 186 187#else /* defined(SMP) */ 188 189#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 190static __inline u_##TYPE \ 191atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 192{ \ 193 u_##TYPE res; \ 194 \ 195 __asm __volatile(__XSTRING(MPLOCKED) LOP \ 196 : "=a" (res), /* 0 (result) */\ 197 "+m" (*p) /* 1 */ \ 198 : : "memory"); \ 199 \ 200 return (res); \ 201} \ 202 \ 203/* \ 204 * The XCHG instruction asserts LOCK automagically. \ 205 */ \ 206static __inline void \ 207atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 208{ \ 209 __asm __volatile(SOP \ 210 : "+m" (*p), /* 0 */ \ 211 "+r" (v) /* 1 */ \ 212 : : "memory"); \ 213} \ 214struct __hack 215 216#endif /* !defined(SMP) */ 217 218#endif /* KLD_MODULE || !__GNUCLIKE_ASM */ 219 220ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 221ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 222ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 223ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 224 225ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 226ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 227ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 228ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 229 230ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 231ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 232ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 233ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 234 235ATOMIC_ASM(set, long, "orl %1,%0", "ir", v); 236ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v); 237ATOMIC_ASM(add, long, "addl %1,%0", "ir", v); 238ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v); 239 240ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 241ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 242ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 243ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0"); 244 245#undef ATOMIC_ASM 246#undef ATOMIC_STORE_LOAD 247 248#if !defined(WANT_FUNCTIONS) 249 250static __inline int 251atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src) 252{ 253 254 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 255 (u_int)src)); 256} 257 258/* Read the current value and store a zero in the destination. */ 259#ifdef __GNUCLIKE_ASM 260 261static __inline u_int 262atomic_readandclear_int(volatile u_int *addr) 263{ 264 u_int result; 265 266 __asm __volatile ( 267 " xorl %0,%0 ; " 268 " xchgl %1,%0 ; " 269 "# atomic_readandclear_int" 270 : "=&r" (result) /* 0 (result) */ 271 : "m" (*addr)); /* 1 (addr) */ 272 273 return (result); 274} 275 276static __inline u_long 277atomic_readandclear_long(volatile u_long *addr) 278{ 279 u_long result; 280 281 __asm __volatile ( 282 " xorl %0,%0 ; " 283 " xchgl %1,%0 ; " 284 "# atomic_readandclear_long" 285 : "=&r" (result) /* 0 (result) */ 286 : "m" (*addr)); /* 1 (addr) */ 287 288 return (result); 289} 290 291#else /* !__GNUCLIKE_ASM */ 292 293u_int atomic_readandclear_int(volatile u_int *); 294u_long atomic_readandclear_long(volatile u_long *); 295 296#endif /* __GNUCLIKE_ASM */ 297 298/* Acquire and release variants are identical to the normal ones. */ 299#define atomic_set_acq_char atomic_set_char 300#define atomic_set_rel_char atomic_set_char 301#define atomic_clear_acq_char atomic_clear_char 302#define atomic_clear_rel_char atomic_clear_char 303#define atomic_add_acq_char atomic_add_char 304#define atomic_add_rel_char atomic_add_char 305#define atomic_subtract_acq_char atomic_subtract_char 306#define atomic_subtract_rel_char atomic_subtract_char 307 308#define atomic_set_acq_short atomic_set_short 309#define atomic_set_rel_short atomic_set_short 310#define atomic_clear_acq_short atomic_clear_short 311#define atomic_clear_rel_short atomic_clear_short 312#define atomic_add_acq_short atomic_add_short 313#define atomic_add_rel_short atomic_add_short 314#define atomic_subtract_acq_short atomic_subtract_short 315#define atomic_subtract_rel_short atomic_subtract_short 316 317#define atomic_set_acq_int atomic_set_int 318#define atomic_set_rel_int atomic_set_int 319#define atomic_clear_acq_int atomic_clear_int 320#define atomic_clear_rel_int atomic_clear_int 321#define atomic_add_acq_int atomic_add_int 322#define atomic_add_rel_int atomic_add_int 323#define atomic_subtract_acq_int atomic_subtract_int 324#define atomic_subtract_rel_int atomic_subtract_int 325#define atomic_cmpset_acq_int atomic_cmpset_int 326#define atomic_cmpset_rel_int atomic_cmpset_int 327 328#define atomic_set_acq_long atomic_set_long 329#define atomic_set_rel_long atomic_set_long 330#define atomic_clear_acq_long atomic_clear_long 331#define atomic_clear_rel_long atomic_clear_long 332#define atomic_add_acq_long atomic_add_long 333#define atomic_add_rel_long atomic_add_long 334#define atomic_subtract_acq_long atomic_subtract_long 335#define atomic_subtract_rel_long atomic_subtract_long 336#define atomic_cmpset_acq_long atomic_cmpset_long 337#define atomic_cmpset_rel_long atomic_cmpset_long 338 339#define atomic_cmpset_acq_ptr atomic_cmpset_ptr 340#define atomic_cmpset_rel_ptr atomic_cmpset_ptr 341 342/* Operations on 8-bit bytes. */ 343#define atomic_set_8 atomic_set_char 344#define atomic_set_acq_8 atomic_set_acq_char 345#define atomic_set_rel_8 atomic_set_rel_char 346#define atomic_clear_8 atomic_clear_char 347#define atomic_clear_acq_8 atomic_clear_acq_char 348#define atomic_clear_rel_8 atomic_clear_rel_char 349#define atomic_add_8 atomic_add_char 350#define atomic_add_acq_8 atomic_add_acq_char 351#define atomic_add_rel_8 atomic_add_rel_char 352#define atomic_subtract_8 atomic_subtract_char 353#define atomic_subtract_acq_8 atomic_subtract_acq_char 354#define atomic_subtract_rel_8 atomic_subtract_rel_char 355#define atomic_load_acq_8 atomic_load_acq_char 356#define atomic_store_rel_8 atomic_store_rel_char 357 358/* Operations on 16-bit words. */ 359#define atomic_set_16 atomic_set_short 360#define atomic_set_acq_16 atomic_set_acq_short 361#define atomic_set_rel_16 atomic_set_rel_short 362#define atomic_clear_16 atomic_clear_short 363#define atomic_clear_acq_16 atomic_clear_acq_short 364#define atomic_clear_rel_16 atomic_clear_rel_short 365#define atomic_add_16 atomic_add_short 366#define atomic_add_acq_16 atomic_add_acq_short 367#define atomic_add_rel_16 atomic_add_rel_short 368#define atomic_subtract_16 atomic_subtract_short 369#define atomic_subtract_acq_16 atomic_subtract_acq_short 370#define atomic_subtract_rel_16 atomic_subtract_rel_short 371#define atomic_load_acq_16 atomic_load_acq_short 372#define atomic_store_rel_16 atomic_store_rel_short 373 374/* Operations on 32-bit double words. */ 375#define atomic_set_32 atomic_set_int 376#define atomic_set_acq_32 atomic_set_acq_int 377#define atomic_set_rel_32 atomic_set_rel_int 378#define atomic_clear_32 atomic_clear_int 379#define atomic_clear_acq_32 atomic_clear_acq_int 380#define atomic_clear_rel_32 atomic_clear_rel_int 381#define atomic_add_32 atomic_add_int 382#define atomic_add_acq_32 atomic_add_acq_int 383#define atomic_add_rel_32 atomic_add_rel_int 384#define atomic_subtract_32 atomic_subtract_int 385#define atomic_subtract_acq_32 atomic_subtract_acq_int 386#define atomic_subtract_rel_32 atomic_subtract_rel_int 387#define atomic_load_acq_32 atomic_load_acq_int 388#define atomic_store_rel_32 atomic_store_rel_int 389#define atomic_cmpset_32 atomic_cmpset_int 390#define atomic_cmpset_acq_32 atomic_cmpset_acq_int 391#define atomic_cmpset_rel_32 atomic_cmpset_rel_int 392#define atomic_readandclear_32 atomic_readandclear_int 393 394/* Operations on pointers. */ 395static __inline int 396atomic_cmpset_ptr(volatile void *dst, void *exp, void *src) 397{ 398 399 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 400 (u_int)src)); 401} 402 403static __inline void * 404atomic_load_acq_ptr(volatile void *p) 405{ 406 /* 407 * The apparently-bogus cast to intptr_t in the following is to 408 * avoid a warning from "gcc -Wbad-function-cast". 409 */ 410 return ((void *)(intptr_t)atomic_load_acq_int((volatile u_int *)p)); 411} 412 413static __inline void 414atomic_store_rel_ptr(volatile void *p, void *v) 415{ 416 atomic_store_rel_int((volatile u_int *)p, (u_int)v); 417} 418 419#define ATOMIC_PTR(NAME) \ 420static __inline void \ 421atomic_##NAME##_ptr(volatile void *p, uintptr_t v) \ 422{ \ 423 atomic_##NAME##_int((volatile u_int *)p, v); \ 424} \ 425 \ 426static __inline void \ 427atomic_##NAME##_acq_ptr(volatile void *p, uintptr_t v) \ 428{ \ 429 atomic_##NAME##_acq_int((volatile u_int *)p, v);\ 430} \ 431 \ 432static __inline void \ 433atomic_##NAME##_rel_ptr(volatile void *p, uintptr_t v) \ 434{ \ 435 atomic_##NAME##_rel_int((volatile u_int *)p, v);\ 436} 437 438ATOMIC_PTR(set) 439ATOMIC_PTR(clear) 440ATOMIC_PTR(add) 441ATOMIC_PTR(subtract) 442 443#undef ATOMIC_PTR 444 445#endif /* !defined(WANT_FUNCTIONS) */ 446#endif /* ! _MACHINE_ATOMIC_H_ */ 447