atomic.h revision 137784
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 137784 2004-11-16 20:42:32Z jhb $ 27 */ 28#ifndef _MACHINE_ATOMIC_H_ 29#define _MACHINE_ATOMIC_H_ 30 31/* 32 * Various simple arithmetic on memory which is atomic in the presence 33 * of interrupts and multiple processors. 34 * 35 * atomic_set_char(P, V) (*(u_char*)(P) |= (V)) 36 * atomic_clear_char(P, V) (*(u_char*)(P) &= ~(V)) 37 * atomic_add_char(P, V) (*(u_char*)(P) += (V)) 38 * atomic_subtract_char(P, V) (*(u_char*)(P) -= (V)) 39 * 40 * atomic_set_short(P, V) (*(u_short*)(P) |= (V)) 41 * atomic_clear_short(P, V) (*(u_short*)(P) &= ~(V)) 42 * atomic_add_short(P, V) (*(u_short*)(P) += (V)) 43 * atomic_subtract_short(P, V) (*(u_short*)(P) -= (V)) 44 * 45 * atomic_set_int(P, V) (*(u_int*)(P) |= (V)) 46 * atomic_clear_int(P, V) (*(u_int*)(P) &= ~(V)) 47 * atomic_add_int(P, V) (*(u_int*)(P) += (V)) 48 * atomic_subtract_int(P, V) (*(u_int*)(P) -= (V)) 49 * atomic_readandclear_int(P) (return *(u_int*)P; *(u_int*)P = 0;) 50 * 51 * atomic_set_long(P, V) (*(u_long*)(P) |= (V)) 52 * atomic_clear_long(P, V) (*(u_long*)(P) &= ~(V)) 53 * atomic_add_long(P, V) (*(u_long*)(P) += (V)) 54 * atomic_subtract_long(P, V) (*(u_long*)(P) -= (V)) 55 * atomic_readandclear_long(P) (return *(u_long*)P; *(u_long*)P = 0;) 56 */ 57 58/* 59 * The above functions are expanded inline in the statically-linked 60 * kernel. Lock prefixes are generated if an SMP kernel is being 61 * built. 62 * 63 * Kernel modules call real functions which are built into the kernel. 64 * This allows kernel modules to be portable between UP and SMP systems. 65 */ 66#if defined(KLD_MODULE) 67#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 68void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 69 70int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src); 71 72#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 73u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 74void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 75 76#else /* !KLD_MODULE */ 77 78#if defined(__GNUC__) || defined(__INTEL_COMPILER) 79 80/* 81 * For userland, assume the SMP case and use lock prefixes so that 82 * the binaries will run on both types of systems. 83 */ 84#if defined(SMP) || !defined(_KERNEL) 85#define MPLOCKED lock ; 86#else 87#define MPLOCKED 88#endif 89 90/* 91 * The assembly is volatilized to demark potential before-and-after side 92 * effects if an interrupt or SMP collision were to occur. 93 */ 94#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 95static __inline void \ 96atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 97{ \ 98 __asm __volatile(__XSTRING(MPLOCKED) OP \ 99 : "+m" (*p) \ 100 : CONS (V)); \ 101} \ 102struct __hack 103 104#else /* !(__GNUC__ || __INTEL_COMPILER) */ 105 106#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 107extern void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 108 109#endif /* __GNUC__ || __INTEL_COMPILER */ 110 111/* 112 * Atomic compare and set, used by the mutex functions 113 * 114 * if (*dst == exp) *dst = src (all 32 bit words) 115 * 116 * Returns 0 on failure, non-zero on success 117 */ 118 119#if defined(__GNUC__) || defined(__INTEL_COMPILER) 120 121#if defined(CPU_DISABLE_CMPXCHG) 122 123static __inline int 124atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 125{ 126 int res = exp; 127 128 __asm __volatile( 129 " pushfl ; " 130 " cli ; " 131 " cmpl %0,%2 ; " 132 " jne 1f ; " 133 " movl %1,%2 ; " 134 "1: " 135 " sete %%al; " 136 " movzbl %%al,%0 ; " 137 " popfl ; " 138 "# atomic_cmpset_int" 139 : "+a" (res) /* 0 (result) */ 140 : "r" (src), /* 1 */ 141 "m" (*(dst)) /* 2 */ 142 : "memory"); 143 144 return (res); 145} 146 147#else /* defined(CPU_DISABLE_CMPXCHG) */ 148 149static __inline int 150atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 151{ 152 int res = exp; 153 154 __asm __volatile ( 155 " " __XSTRING(MPLOCKED) " " 156 " cmpxchgl %1,%2 ; " 157 " setz %%al ; " 158 " movzbl %%al,%0 ; " 159 "1: " 160 "# atomic_cmpset_int" 161 : "+a" (res) /* 0 (result) */ 162 : "r" (src), /* 1 */ 163 "m" (*(dst)) /* 2 */ 164 : "memory"); 165 166 return (res); 167} 168 169#endif /* defined(CPU_DISABLE_CMPXCHG) */ 170 171#endif /* defined(__GNUC__) || defined(__INTEL_COMPILER) */ 172 173#if defined(__GNUC__) || defined(__INTEL_COMPILER) 174 175#if defined(_KERNEL) && !defined(SMP) 176 177/* 178 * We assume that a = b will do atomic loads and stores. However, on a 179 * PentiumPro or higher, reads may pass writes, so for that case we have 180 * to use a serializing instruction (i.e. with LOCK) to do the load in 181 * SMP kernels. For UP kernels, however, the cache of the single processor 182 * is always consistent, so we don't need any memory barriers. 183 */ 184#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 185static __inline u_##TYPE \ 186atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 187{ \ 188 return (*p); \ 189} \ 190 \ 191static __inline void \ 192atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 193{ \ 194 *p = v; \ 195} \ 196struct __hack 197 198#else /* defined(SMP) */ 199 200#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 201static __inline u_##TYPE \ 202atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 203{ \ 204 u_##TYPE res; \ 205 \ 206 __asm __volatile(__XSTRING(MPLOCKED) LOP \ 207 : "=a" (res), /* 0 (result) */\ 208 "+m" (*p) /* 1 */ \ 209 : : "memory"); \ 210 \ 211 return (res); \ 212} \ 213 \ 214/* \ 215 * The XCHG instruction asserts LOCK automagically. \ 216 */ \ 217static __inline void \ 218atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 219{ \ 220 __asm __volatile(SOP \ 221 : "+m" (*p), /* 0 */ \ 222 "+r" (v) /* 1 */ \ 223 : : "memory"); \ 224} \ 225struct __hack 226 227#endif /* !defined(SMP) */ 228 229#else /* !(defined(__GNUC__) || defined(__INTEL_COMPILER)) */ 230 231extern int atomic_cmpset_int(volatile u_int *, u_int, u_int); 232 233#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 234extern u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 235extern void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 236 237#endif /* defined(__GNUC__) || defined(__INTEL_COMPILER) */ 238 239#endif /* KLD_MODULE */ 240 241ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 242ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 243ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 244ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 245 246ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 247ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 248ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 249ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 250 251ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 252ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 253ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 254ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 255 256ATOMIC_ASM(set, long, "orl %1,%0", "ir", v); 257ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v); 258ATOMIC_ASM(add, long, "addl %1,%0", "ir", v); 259ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v); 260 261ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 262ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 263ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 264ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0"); 265 266#undef ATOMIC_ASM 267#undef ATOMIC_STORE_LOAD 268 269#define atomic_set_acq_char atomic_set_char 270#define atomic_set_rel_char atomic_set_char 271#define atomic_clear_acq_char atomic_clear_char 272#define atomic_clear_rel_char atomic_clear_char 273#define atomic_add_acq_char atomic_add_char 274#define atomic_add_rel_char atomic_add_char 275#define atomic_subtract_acq_char atomic_subtract_char 276#define atomic_subtract_rel_char atomic_subtract_char 277 278#define atomic_set_acq_short atomic_set_short 279#define atomic_set_rel_short atomic_set_short 280#define atomic_clear_acq_short atomic_clear_short 281#define atomic_clear_rel_short atomic_clear_short 282#define atomic_add_acq_short atomic_add_short 283#define atomic_add_rel_short atomic_add_short 284#define atomic_subtract_acq_short atomic_subtract_short 285#define atomic_subtract_rel_short atomic_subtract_short 286 287#define atomic_set_acq_int atomic_set_int 288#define atomic_set_rel_int atomic_set_int 289#define atomic_clear_acq_int atomic_clear_int 290#define atomic_clear_rel_int atomic_clear_int 291#define atomic_add_acq_int atomic_add_int 292#define atomic_add_rel_int atomic_add_int 293#define atomic_subtract_acq_int atomic_subtract_int 294#define atomic_subtract_rel_int atomic_subtract_int 295#define atomic_cmpset_acq_int atomic_cmpset_int 296#define atomic_cmpset_rel_int atomic_cmpset_int 297 298#define atomic_set_acq_long atomic_set_long 299#define atomic_set_rel_long atomic_set_long 300#define atomic_clear_acq_long atomic_clear_long 301#define atomic_clear_rel_long atomic_clear_long 302#define atomic_add_acq_long atomic_add_long 303#define atomic_add_rel_long atomic_add_long 304#define atomic_subtract_acq_long atomic_subtract_long 305#define atomic_subtract_rel_long atomic_subtract_long 306#define atomic_cmpset_long atomic_cmpset_int 307#define atomic_cmpset_acq_long atomic_cmpset_acq_int 308#define atomic_cmpset_rel_long atomic_cmpset_rel_int 309 310#define atomic_cmpset_acq_ptr atomic_cmpset_ptr 311#define atomic_cmpset_rel_ptr atomic_cmpset_ptr 312 313#define atomic_set_8 atomic_set_char 314#define atomic_set_acq_8 atomic_set_acq_char 315#define atomic_set_rel_8 atomic_set_rel_char 316#define atomic_clear_8 atomic_clear_char 317#define atomic_clear_acq_8 atomic_clear_acq_char 318#define atomic_clear_rel_8 atomic_clear_rel_char 319#define atomic_add_8 atomic_add_char 320#define atomic_add_acq_8 atomic_add_acq_char 321#define atomic_add_rel_8 atomic_add_rel_char 322#define atomic_subtract_8 atomic_subtract_char 323#define atomic_subtract_acq_8 atomic_subtract_acq_char 324#define atomic_subtract_rel_8 atomic_subtract_rel_char 325#define atomic_load_acq_8 atomic_load_acq_char 326#define atomic_store_rel_8 atomic_store_rel_char 327 328#define atomic_set_16 atomic_set_short 329#define atomic_set_acq_16 atomic_set_acq_short 330#define atomic_set_rel_16 atomic_set_rel_short 331#define atomic_clear_16 atomic_clear_short 332#define atomic_clear_acq_16 atomic_clear_acq_short 333#define atomic_clear_rel_16 atomic_clear_rel_short 334#define atomic_add_16 atomic_add_short 335#define atomic_add_acq_16 atomic_add_acq_short 336#define atomic_add_rel_16 atomic_add_rel_short 337#define atomic_subtract_16 atomic_subtract_short 338#define atomic_subtract_acq_16 atomic_subtract_acq_short 339#define atomic_subtract_rel_16 atomic_subtract_rel_short 340#define atomic_load_acq_16 atomic_load_acq_short 341#define atomic_store_rel_16 atomic_store_rel_short 342 343#define atomic_set_32 atomic_set_int 344#define atomic_set_acq_32 atomic_set_acq_int 345#define atomic_set_rel_32 atomic_set_rel_int 346#define atomic_clear_32 atomic_clear_int 347#define atomic_clear_acq_32 atomic_clear_acq_int 348#define atomic_clear_rel_32 atomic_clear_rel_int 349#define atomic_add_32 atomic_add_int 350#define atomic_add_acq_32 atomic_add_acq_int 351#define atomic_add_rel_32 atomic_add_rel_int 352#define atomic_subtract_32 atomic_subtract_int 353#define atomic_subtract_acq_32 atomic_subtract_acq_int 354#define atomic_subtract_rel_32 atomic_subtract_rel_int 355#define atomic_load_acq_32 atomic_load_acq_int 356#define atomic_store_rel_32 atomic_store_rel_int 357#define atomic_cmpset_32 atomic_cmpset_int 358#define atomic_cmpset_acq_32 atomic_cmpset_acq_int 359#define atomic_cmpset_rel_32 atomic_cmpset_rel_int 360#define atomic_readandclear_32 atomic_readandclear_int 361 362#if !defined(WANT_FUNCTIONS) 363static __inline int 364atomic_cmpset_ptr(volatile void *dst, void *exp, void *src) 365{ 366 367 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 368 (u_int)src)); 369} 370 371static __inline void * 372atomic_load_acq_ptr(volatile void *p) 373{ 374 /* 375 * The apparently-bogus cast to intptr_t in the following is to 376 * avoid a warning from "gcc -Wbad-function-cast". 377 */ 378 return ((void *)(intptr_t)atomic_load_acq_int((volatile u_int *)p)); 379} 380 381static __inline void 382atomic_store_rel_ptr(volatile void *p, void *v) 383{ 384 atomic_store_rel_int((volatile u_int *)p, (u_int)v); 385} 386 387#define ATOMIC_PTR(NAME) \ 388static __inline void \ 389atomic_##NAME##_ptr(volatile void *p, uintptr_t v) \ 390{ \ 391 atomic_##NAME##_int((volatile u_int *)p, v); \ 392} \ 393 \ 394static __inline void \ 395atomic_##NAME##_acq_ptr(volatile void *p, uintptr_t v) \ 396{ \ 397 atomic_##NAME##_acq_int((volatile u_int *)p, v);\ 398} \ 399 \ 400static __inline void \ 401atomic_##NAME##_rel_ptr(volatile void *p, uintptr_t v) \ 402{ \ 403 atomic_##NAME##_rel_int((volatile u_int *)p, v);\ 404} 405 406ATOMIC_PTR(set) 407ATOMIC_PTR(clear) 408ATOMIC_PTR(add) 409ATOMIC_PTR(subtract) 410 411#undef ATOMIC_PTR 412 413#if defined(__GNUC__) || defined(__INTEL_COMPILER) 414 415static __inline u_int 416atomic_readandclear_int(volatile u_int *addr) 417{ 418 u_int result; 419 420 __asm __volatile ( 421 " xorl %0,%0 ; " 422 " xchgl %1,%0 ; " 423 "# atomic_readandclear_int" 424 : "=&r" (result) /* 0 (result) */ 425 : "m" (*addr)); /* 1 (addr) */ 426 427 return (result); 428} 429 430static __inline u_long 431atomic_readandclear_long(volatile u_long *addr) 432{ 433 u_long result; 434 435 __asm __volatile ( 436 " xorl %0,%0 ; " 437 " xchgl %1,%0 ; " 438 "# atomic_readandclear_int" 439 : "=&r" (result) /* 0 (result) */ 440 : "m" (*addr)); /* 1 (addr) */ 441 442 return (result); 443} 444 445#else /* !(defined(__GNUC__) || defined(__INTEL_COMPILER)) */ 446 447extern u_long atomic_readandclear_long(volatile u_long *); 448extern u_int atomic_readandclear_int(volatile u_int *); 449 450#endif /* defined(__GNUC__) || defined(__INTEL_COMPILER) */ 451 452#endif /* !defined(WANT_FUNCTIONS) */ 453#endif /* ! _MACHINE_ATOMIC_H_ */ 454