atomic.h revision 100327
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 100327 2002-07-18 15:56:46Z markm $ 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#ifdef __GNUC__ 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} 102 103#else /* !__GNUC__ */ 104 105#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 106extern void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 107 108#endif /* __GNUC__ */ 109 110/* 111 * Atomic compare and set, used by the mutex functions 112 * 113 * if (*dst == exp) *dst = src (all 32 bit words) 114 * 115 * Returns 0 on failure, non-zero on success 116 */ 117 118#if defined(__GNUC__) 119 120#if defined(I386_CPU) 121 122static __inline int 123atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 124{ 125 int res = exp; 126 127 __asm __volatile( 128 " pushfl ; " 129 " cli ; " 130 " cmpl %0,%2 ; " 131 " jne 1f ; " 132 " movl %1,%2 ; " 133 "1: " 134 " sete %%al; " 135 " movzbl %%al,%0 ; " 136 " popfl ; " 137 "# atomic_cmpset_int" 138 : "+a" (res) /* 0 (result) */ 139 : "r" (src), /* 1 */ 140 "m" (*(dst)) /* 2 */ 141 : "memory"); 142 143 return (res); 144} 145 146#else /* defined(I386_CPU) */ 147 148static __inline int 149atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 150{ 151 int res = exp; 152 153 __asm __volatile ( 154 " " __XSTRING(MPLOCKED) " " 155 " cmpxchgl %1,%2 ; " 156 " setz %%al ; " 157 " movzbl %%al,%0 ; " 158 "1: " 159 "# atomic_cmpset_int" 160 : "+a" (res) /* 0 (result) */ 161 : "r" (src), /* 1 */ 162 "m" (*(dst)) /* 2 */ 163 : "memory"); 164 165 return (res); 166} 167 168#endif /* defined(I386_CPU) */ 169 170#endif /* defined(__GNUC__) */ 171 172#if defined(__GNUC__) 173 174#if defined(I386_CPU) 175 176/* 177 * We assume that a = b will do atomic loads and stores. 178 * 179 * XXX: This is _NOT_ safe on a P6 or higher because it does not guarantee 180 * memory ordering. These should only be used on a 386. 181 */ 182#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 183static __inline u_##TYPE \ 184atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 185{ \ 186 return (*p); \ 187} \ 188 \ 189static __inline void \ 190atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 191{ \ 192 *p = v; \ 193 __asm __volatile("" : : : "memory"); \ 194} 195 196#else /* !defined(I386_CPU) */ 197 198#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 199static __inline u_##TYPE \ 200atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 201{ \ 202 u_##TYPE res; \ 203 \ 204 __asm __volatile(__XSTRING(MPLOCKED) LOP \ 205 : "=a" (res), /* 0 (result) */\ 206 "+m" (*p) /* 1 */ \ 207 : : "memory"); \ 208 \ 209 return (res); \ 210} \ 211 \ 212/* \ 213 * The XCHG instruction asserts LOCK automagically. \ 214 */ \ 215static __inline void \ 216atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 217{ \ 218 __asm __volatile(SOP \ 219 : "+m" (*p), /* 0 */ \ 220 "+r" (v) /* 1 */ \ 221 : : "memory"); \ 222} 223 224#endif /* defined(I386_CPU) */ 225 226#else /* !defined(__GNUC__) */ 227 228extern int atomic_cmpset_int(volatile u_int *, u_int, u_int); 229 230#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 231extern u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 232extern void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 233 234#endif /* defined(__GNUC__) */ 235 236#endif /* KLD_MODULE */ 237 238ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 239ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 240ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 241ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 242 243ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 244ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 245ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 246ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 247 248ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 249ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 250ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 251ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 252 253ATOMIC_ASM(set, long, "orl %1,%0", "ir", v); 254ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v); 255ATOMIC_ASM(add, long, "addl %1,%0", "ir", v); 256ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v); 257 258ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 259ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 260ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 261ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0"); 262 263#undef ATOMIC_ASM 264#undef ATOMIC_STORE_LOAD 265 266#define atomic_set_acq_char atomic_set_char 267#define atomic_set_rel_char atomic_set_char 268#define atomic_clear_acq_char atomic_clear_char 269#define atomic_clear_rel_char atomic_clear_char 270#define atomic_add_acq_char atomic_add_char 271#define atomic_add_rel_char atomic_add_char 272#define atomic_subtract_acq_char atomic_subtract_char 273#define atomic_subtract_rel_char atomic_subtract_char 274 275#define atomic_set_acq_short atomic_set_short 276#define atomic_set_rel_short atomic_set_short 277#define atomic_clear_acq_short atomic_clear_short 278#define atomic_clear_rel_short atomic_clear_short 279#define atomic_add_acq_short atomic_add_short 280#define atomic_add_rel_short atomic_add_short 281#define atomic_subtract_acq_short atomic_subtract_short 282#define atomic_subtract_rel_short atomic_subtract_short 283 284#define atomic_set_acq_int atomic_set_int 285#define atomic_set_rel_int atomic_set_int 286#define atomic_clear_acq_int atomic_clear_int 287#define atomic_clear_rel_int atomic_clear_int 288#define atomic_add_acq_int atomic_add_int 289#define atomic_add_rel_int atomic_add_int 290#define atomic_subtract_acq_int atomic_subtract_int 291#define atomic_subtract_rel_int atomic_subtract_int 292#define atomic_cmpset_acq_int atomic_cmpset_int 293#define atomic_cmpset_rel_int atomic_cmpset_int 294 295#define atomic_set_acq_long atomic_set_long 296#define atomic_set_rel_long atomic_set_long 297#define atomic_clear_acq_long atomic_clear_long 298#define atomic_clear_rel_long atomic_clear_long 299#define atomic_add_acq_long atomic_add_long 300#define atomic_add_rel_long atomic_add_long 301#define atomic_subtract_acq_long atomic_subtract_long 302#define atomic_subtract_rel_long atomic_subtract_long 303#define atomic_cmpset_long atomic_cmpset_int 304#define atomic_cmpset_acq_long atomic_cmpset_acq_int 305#define atomic_cmpset_rel_long atomic_cmpset_rel_int 306 307#define atomic_cmpset_acq_ptr atomic_cmpset_ptr 308#define atomic_cmpset_rel_ptr atomic_cmpset_ptr 309 310#define atomic_set_8 atomic_set_char 311#define atomic_set_acq_8 atomic_set_acq_char 312#define atomic_set_rel_8 atomic_set_rel_char 313#define atomic_clear_8 atomic_clear_char 314#define atomic_clear_acq_8 atomic_clear_acq_char 315#define atomic_clear_rel_8 atomic_clear_rel_char 316#define atomic_add_8 atomic_add_char 317#define atomic_add_acq_8 atomic_add_acq_char 318#define atomic_add_rel_8 atomic_add_rel_char 319#define atomic_subtract_8 atomic_subtract_char 320#define atomic_subtract_acq_8 atomic_subtract_acq_char 321#define atomic_subtract_rel_8 atomic_subtract_rel_char 322#define atomic_load_acq_8 atomic_load_acq_char 323#define atomic_store_rel_8 atomic_store_rel_char 324 325#define atomic_set_16 atomic_set_short 326#define atomic_set_acq_16 atomic_set_acq_short 327#define atomic_set_rel_16 atomic_set_rel_short 328#define atomic_clear_16 atomic_clear_short 329#define atomic_clear_acq_16 atomic_clear_acq_short 330#define atomic_clear_rel_16 atomic_clear_rel_short 331#define atomic_add_16 atomic_add_short 332#define atomic_add_acq_16 atomic_add_acq_short 333#define atomic_add_rel_16 atomic_add_rel_short 334#define atomic_subtract_16 atomic_subtract_short 335#define atomic_subtract_acq_16 atomic_subtract_acq_short 336#define atomic_subtract_rel_16 atomic_subtract_rel_short 337#define atomic_load_acq_16 atomic_load_acq_short 338#define atomic_store_rel_16 atomic_store_rel_short 339 340#define atomic_set_32 atomic_set_int 341#define atomic_set_acq_32 atomic_set_acq_int 342#define atomic_set_rel_32 atomic_set_rel_int 343#define atomic_clear_32 atomic_clear_int 344#define atomic_clear_acq_32 atomic_clear_acq_int 345#define atomic_clear_rel_32 atomic_clear_rel_int 346#define atomic_add_32 atomic_add_int 347#define atomic_add_acq_32 atomic_add_acq_int 348#define atomic_add_rel_32 atomic_add_rel_int 349#define atomic_subtract_32 atomic_subtract_int 350#define atomic_subtract_acq_32 atomic_subtract_acq_int 351#define atomic_subtract_rel_32 atomic_subtract_rel_int 352#define atomic_load_acq_32 atomic_load_acq_int 353#define atomic_store_rel_32 atomic_store_rel_int 354#define atomic_cmpset_32 atomic_cmpset_int 355#define atomic_cmpset_acq_32 atomic_cmpset_acq_int 356#define atomic_cmpset_rel_32 atomic_cmpset_rel_int 357#define atomic_readandclear_32 atomic_readandclear_int 358 359#if !defined(WANT_FUNCTIONS) 360static __inline int 361atomic_cmpset_ptr(volatile void *dst, void *exp, void *src) 362{ 363 364 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 365 (u_int)src)); 366} 367 368static __inline void * 369atomic_load_acq_ptr(volatile void *p) 370{ 371 return (void *)atomic_load_acq_int((volatile u_int *)p); 372} 373 374static __inline void 375atomic_store_rel_ptr(volatile void *p, void *v) 376{ 377 atomic_store_rel_int((volatile u_int *)p, (u_int)v); 378} 379 380#define ATOMIC_PTR(NAME) \ 381static __inline void \ 382atomic_##NAME##_ptr(volatile void *p, uintptr_t v) \ 383{ \ 384 atomic_##NAME##_int((volatile u_int *)p, v); \ 385} \ 386 \ 387static __inline void \ 388atomic_##NAME##_acq_ptr(volatile void *p, uintptr_t v) \ 389{ \ 390 atomic_##NAME##_acq_int((volatile u_int *)p, v);\ 391} \ 392 \ 393static __inline void \ 394atomic_##NAME##_rel_ptr(volatile void *p, uintptr_t v) \ 395{ \ 396 atomic_##NAME##_rel_int((volatile u_int *)p, v);\ 397} 398 399ATOMIC_PTR(set) 400ATOMIC_PTR(clear) 401ATOMIC_PTR(add) 402ATOMIC_PTR(subtract) 403 404#undef ATOMIC_PTR 405 406#if defined(__GNUC__) 407 408static __inline u_int 409atomic_readandclear_int(volatile u_int *addr) 410{ 411 u_int result; 412 413 __asm __volatile ( 414 " xorl %0,%0 ; " 415 " xchgl %1,%0 ; " 416 "# atomic_readandclear_int" 417 : "=&r" (result) /* 0 (result) */ 418 : "m" (*addr)); /* 1 (addr) */ 419 420 return (result); 421} 422 423static __inline u_long 424atomic_readandclear_long(volatile u_long *addr) 425{ 426 u_long result; 427 428 __asm __volatile ( 429 " xorl %0,%0 ; " 430 " xchgl %1,%0 ; " 431 "# atomic_readandclear_int" 432 : "=&r" (result) /* 0 (result) */ 433 : "m" (*addr)); /* 1 (addr) */ 434 435 return (result); 436} 437 438#else /* !defined(__GNUC__) */ 439 440extern u_long atomic_readandclear_long(volatile u_long *); 441extern u_int atomic_readandclear_int(volatile u_int *); 442 443#endif /* defined(__GNUC__) */ 444 445#endif /* !defined(WANT_FUNCTIONS) */ 446#endif /* ! _MACHINE_ATOMIC_H_ */ 447