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_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) \ 76 void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 77 78 int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src); 79 int atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src); 80 u_int atomic_fetchadd_int(volatile u_int *p, u_int v); 81 u_long atomic_fetchadd_long(volatile u_long *p, u_long v); 82 83 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 84 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 85 void 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 demark potential before-and-after side 101 * effects if an interrupt or SMP collision were to occur. 102 */ 103 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 104 static __inline void \ 105 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 106 { \ 107 __asm __volatile(MPLOCKED OP \ 108 : "=m" (*p) \ 109 : CONS (V), "m" (*p)); \ 110 } \ 111 struct __hack 112 113 /* 114 * Atomic compare and set, used by the mutex functions 115 * 116 * if (*dst == exp) *dst = src (all 32 bit words) 117 * 118 * Returns 0 on failure, non-zero on success 119 */ 120 121 static __inline int 122 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 123 { 124 u_char res; 125 126 __asm __volatile( 127 " " MPLOCKED " " 128 " cmpxchgl %2,%1 ; " 129 " sete %0 ; " 130 "1: " 131 "# atomic_cmpset_int" 132 : "=a" (res), /* 0 */ 133 "=m" (*dst) /* 1 */ 134 : "r" (src), /* 2 */ 135 "a" (exp), /* 3 */ 136 "m" (*dst) /* 4 */ 137 : "memory"); 138 139 return (res); 140 } 141 142 static __inline int 143 atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src) 144 { 145 u_char res; 146 147 __asm __volatile( 148 " " MPLOCKED " " 149 " cmpxchgq %2,%1 ; " 150 " sete %0 ; " 151 "1: " 152 "# atomic_cmpset_long" 153 : "=a" (res), /* 0 */ 154 "=m" (*dst) /* 1 */ 155 : "r" (src), /* 2 */ 156 "a" (exp), /* 3 */ 157 "m" (*dst) /* 4 */ 158 : "memory"); 159 160 return (res); 161 } 162 163 /* 164 * Atomically add the value of v to the integer pointed to by p and return 165 * the previous value of *p. 166 */ 167 static __inline u_int 168 atomic_fetchadd_int(volatile u_int *p, u_int v) 169 { 170 171 __asm __volatile( 172 " " MPLOCKED " " 173 " xaddl %0, %1 ; " 174 "# atomic_fetchadd_int" 175 : "+r" (v), /* 0 (result) */ 176 "=m" (*p) /* 1 */ 177 : "m" (*p)); /* 2 */ 178 179 return (v); 180 } 181 182 /* 183 * Atomically add the value of v to the long integer pointed to by p and return 184 * the previous value of *p. 185 */ 186 static __inline u_long 187 atomic_fetchadd_long(volatile u_long *p, u_long v) 188 { 189 190 __asm __volatile( 191 " " MPLOCKED " " 192 " xaddq %0, %1 ; " 193 "# atomic_fetchadd_long" 194 : "+r" (v), /* 0 (result) */ 195 "=m" (*p) /* 1 */ 196 : "m" (*p)); /* 2 */ 197 198 return (v); 199 } 200 201 #if defined(_KERNEL) && !defined(SMP) 202 203 /* 204 * We assume that a = b will do atomic loads and stores. However, on a 205 * PentiumPro or higher, reads may pass writes, so for that case we have 206 * to use a serializing instruction (i.e. with LOCK) to do the load in 207 * SMP kernels. For UP kernels, however, the cache of the single processor 208 * is always consistent, so we don't need any memory barriers. 209 */ 210 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 211 static __inline u_##TYPE \ 212 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 213 { \ 214 return (*p); \ 215 } \ 216 \ 217 static __inline void \ 218 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 219 { \ 220 *p = v; \ 221 } \ 222 struct __hack 223 224 #else /* !(_KERNEL && !SMP) */ 225 226 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 227 static __inline u_##TYPE \ 228 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 229 { \ 230 u_##TYPE res; \ 231 \ 232 __asm __volatile(MPLOCKED LOP \ 233 : "=a" (res), /* 0 */ \ 234 "=m" (*p) /* 1 */ \ 235 : "m" (*p) /* 2 */ \ 236 : "memory"); \ 237 \ 238 return (res); \ 239 } \ 240 \ 241 /* \ 242 * The XCHG instruction asserts LOCK automagically. \ 243 */ \ 244 static __inline void \ 245 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 246 { \ 247 __asm __volatile(SOP \ 248 : "=m" (*p), /* 0 */ \ 249 "+r" (v) /* 1 */ \ 250 : "m" (*p)); /* 2 */ \ 251 } \ 252 struct __hack 253 254 #endif /* _KERNEL && !SMP */ 255 256 #endif /* KLD_MODULE || !__GNUCLIKE_ASM */ 257 258 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 259 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 260 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 261 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 262 263 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 264 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 265 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 266 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 267 268 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 269 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 270 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 271 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 272 273 ATOMIC_ASM(set, long, "orq %1,%0", "ir", v); 274 ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v); 275 ATOMIC_ASM(add, long, "addq %1,%0", "ir", v); 276 ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v); 277 278 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 279 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 280 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 281 ATOMIC_STORE_LOAD(long, "cmpxchgq %0,%1", "xchgq %1,%0"); 282 283 #undef ATOMIC_ASM 284 #undef ATOMIC_STORE_LOAD 285 286 #ifndef WANT_FUNCTIONS 287 288 /* Read the current value and store a zero in the destination. */ 289 #ifdef __GNUCLIKE_ASM 290 291 static __inline u_int 292 atomic_readandclear_int(volatile u_int *addr) 293 { 294 u_int res; 295 296 res = 0; 297 __asm __volatile( 298 " xchgl %1,%0 ; " 299 "# atomic_readandclear_int" 300 : "+r" (res), /* 0 */ 301 "=m" (*addr) /* 1 */ 302 : "m" (*addr)); 303 304 return (res); 305 } 306 307 static __inline u_long 308 atomic_readandclear_long(volatile u_long *addr) 309 { 310 u_long res; 311 312 res = 0; 313 __asm __volatile( 314 " xchgq %1,%0 ; " 315 "# atomic_readandclear_long" 316 : "+r" (res), /* 0 */ 317 "=m" (*addr) /* 1 */ 318 : "m" (*addr)); 319 320 return (res); 321 } 322 323 #else /* !__GNUCLIKE_ASM */ 324 325 u_int atomic_readandclear_int(volatile u_int *addr); 326 u_long atomic_readandclear_long(volatile u_long *addr); 327 328 #endif /* __GNUCLIKE_ASM */ 329 330 /* Acquire and release variants are identical to the normal ones. */ 331 #define atomic_set_acq_char atomic_set_char 332 #define atomic_set_rel_char atomic_set_char 333 #define atomic_clear_acq_char atomic_clear_char 334 #define atomic_clear_rel_char atomic_clear_char 335 #define atomic_add_acq_char atomic_add_char 336 #define atomic_add_rel_char atomic_add_char 337 #define atomic_subtract_acq_char atomic_subtract_char 338 #define atomic_subtract_rel_char atomic_subtract_char 339 340 #define atomic_set_acq_short atomic_set_short 341 #define atomic_set_rel_short atomic_set_short 342 #define atomic_clear_acq_short atomic_clear_short 343 #define atomic_clear_rel_short atomic_clear_short 344 #define atomic_add_acq_short atomic_add_short 345 #define atomic_add_rel_short atomic_add_short 346 #define atomic_subtract_acq_short atomic_subtract_short 347 #define atomic_subtract_rel_short atomic_subtract_short 348 349 #define atomic_set_acq_int atomic_set_int 350 #define atomic_set_rel_int atomic_set_int 351 #define atomic_clear_acq_int atomic_clear_int 352 #define atomic_clear_rel_int atomic_clear_int 353 #define atomic_add_acq_int atomic_add_int 354 #define atomic_add_rel_int atomic_add_int 355 #define atomic_subtract_acq_int atomic_subtract_int 356 #define atomic_subtract_rel_int atomic_subtract_int 357 #define atomic_cmpset_acq_int atomic_cmpset_int 358 #define atomic_cmpset_rel_int atomic_cmpset_int 359 360 #define atomic_set_acq_long atomic_set_long 361 #define atomic_set_rel_long atomic_set_long 362 #define atomic_clear_acq_long atomic_clear_long 363 #define atomic_clear_rel_long atomic_clear_long 364 #define atomic_add_acq_long atomic_add_long 365 #define atomic_add_rel_long atomic_add_long 366 #define atomic_subtract_acq_long atomic_subtract_long 367 #define atomic_subtract_rel_long atomic_subtract_long 368 #define atomic_cmpset_acq_long atomic_cmpset_long 369 #define atomic_cmpset_rel_long atomic_cmpset_long 370 371 /* Operations on 8-bit bytes. */ 372 #define atomic_set_8 atomic_set_char 373 #define atomic_set_acq_8 atomic_set_acq_char 374 #define atomic_set_rel_8 atomic_set_rel_char 375 #define atomic_clear_8 atomic_clear_char 376 #define atomic_clear_acq_8 atomic_clear_acq_char 377 #define atomic_clear_rel_8 atomic_clear_rel_char 378 #define atomic_add_8 atomic_add_char 379 #define atomic_add_acq_8 atomic_add_acq_char 380 #define atomic_add_rel_8 atomic_add_rel_char 381 #define atomic_subtract_8 atomic_subtract_char 382 #define atomic_subtract_acq_8 atomic_subtract_acq_char 383 #define atomic_subtract_rel_8 atomic_subtract_rel_char 384 #define atomic_load_acq_8 atomic_load_acq_char 385 #define atomic_store_rel_8 atomic_store_rel_char 386 387 /* Operations on 16-bit words. */ 388 #define atomic_set_16 atomic_set_short 389 #define atomic_set_acq_16 atomic_set_acq_short 390 #define atomic_set_rel_16 atomic_set_rel_short 391 #define atomic_clear_16 atomic_clear_short 392 #define atomic_clear_acq_16 atomic_clear_acq_short 393 #define atomic_clear_rel_16 atomic_clear_rel_short 394 #define atomic_add_16 atomic_add_short 395 #define atomic_add_acq_16 atomic_add_acq_short 396 #define atomic_add_rel_16 atomic_add_rel_short 397 #define atomic_subtract_16 atomic_subtract_short 398 #define atomic_subtract_acq_16 atomic_subtract_acq_short 399 #define atomic_subtract_rel_16 atomic_subtract_rel_short 400 #define atomic_load_acq_16 atomic_load_acq_short 401 #define atomic_store_rel_16 atomic_store_rel_short 402 403 /* Operations on 32-bit double words. */ 404 #define atomic_set_32 atomic_set_int 405 #define atomic_set_acq_32 atomic_set_acq_int 406 #define atomic_set_rel_32 atomic_set_rel_int 407 #define atomic_clear_32 atomic_clear_int 408 #define atomic_clear_acq_32 atomic_clear_acq_int 409 #define atomic_clear_rel_32 atomic_clear_rel_int 410 #define atomic_add_32 atomic_add_int 411 #define atomic_add_acq_32 atomic_add_acq_int 412 #define atomic_add_rel_32 atomic_add_rel_int 413 #define atomic_subtract_32 atomic_subtract_int 414 #define atomic_subtract_acq_32 atomic_subtract_acq_int 415 #define atomic_subtract_rel_32 atomic_subtract_rel_int 416 #define atomic_load_acq_32 atomic_load_acq_int 417 #define atomic_store_rel_32 atomic_store_rel_int 418 #define atomic_cmpset_32 atomic_cmpset_int 419 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int 420 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int 421 #define atomic_readandclear_32 atomic_readandclear_int 422 #define atomic_fetchadd_32 atomic_fetchadd_int 423 424 /* Operations on 64-bit quad words. */ 425 #define atomic_set_64 atomic_set_long 426 #define atomic_set_acq_64 atomic_set_acq_long 427 #define atomic_set_rel_64 atomic_set_rel_long 428 #define atomic_clear_64 atomic_clear_long 429 #define atomic_clear_acq_64 atomic_clear_acq_long 430 #define atomic_clear_rel_64 atomic_clear_rel_long 431 #define atomic_add_64 atomic_add_long 432 #define atomic_add_acq_64 atomic_add_acq_long 433 #define atomic_add_rel_64 atomic_add_rel_long 434 #define atomic_subtract_64 atomic_subtract_long 435 #define atomic_subtract_acq_64 atomic_subtract_acq_long 436 #define atomic_subtract_rel_64 atomic_subtract_rel_long 437 #define atomic_load_acq_64 atomic_load_acq_long 438 #define atomic_store_rel_64 atomic_store_rel_long 439 #define atomic_cmpset_64 atomic_cmpset_long 440 #define atomic_cmpset_acq_64 atomic_cmpset_acq_long 441 #define atomic_cmpset_rel_64 atomic_cmpset_rel_long 442 #define atomic_readandclear_64 atomic_readandclear_long 443 444 /* Operations on pointers. */ 445 #define atomic_set_ptr atomic_set_long 446 #define atomic_set_acq_ptr atomic_set_acq_long 447 #define atomic_set_rel_ptr atomic_set_rel_long 448 #define atomic_clear_ptr atomic_clear_long 449 #define atomic_clear_acq_ptr atomic_clear_acq_long 450 #define atomic_clear_rel_ptr atomic_clear_rel_long 451 #define atomic_add_ptr atomic_add_long 452 #define atomic_add_acq_ptr atomic_add_acq_long 453 #define atomic_add_rel_ptr atomic_add_rel_long 454 #define atomic_subtract_ptr atomic_subtract_long 455 #define atomic_subtract_acq_ptr atomic_subtract_acq_long 456 #define atomic_subtract_rel_ptr atomic_subtract_rel_long 457 #define atomic_load_acq_ptr atomic_load_acq_long 458 #define atomic_store_rel_ptr atomic_store_rel_long 459 #define atomic_cmpset_ptr atomic_cmpset_long 460 #define atomic_cmpset_acq_ptr atomic_cmpset_acq_long 461 #define atomic_cmpset_rel_ptr atomic_cmpset_rel_long 462 #define atomic_readandclear_ptr atomic_readandclear_long 463 464 #endif /* !WANT_FUNCTIONS */ 465 466 #endif /* !_MACHINE_ATOMIC_H_ */ 467