atomic.h revision 148267
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 148267 2005-07-21 22:35:02Z peter $ 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); 76 77#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 78u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 79void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) 80 81#else /* !KLD_MODULE && __GNUCLIKE_ASM && __CC_SUPPORTS___INLINE */ 82 83/* 84 * For userland, assume the SMP case and use lock prefixes so that 85 * the binaries will run on both types of systems. 86 */ 87#if defined(SMP) || !defined(_KERNEL) 88#define MPLOCKED lock ; 89#else 90#define MPLOCKED 91#endif 92 93/* 94 * The assembly is volatilized to demark potential before-and-after side 95 * effects if an interrupt or SMP collision were to occur. 96 */ 97#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 98static __inline void \ 99atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 100{ \ 101 __asm __volatile(__XSTRING(MPLOCKED) OP \ 102 : "+m" (*p) \ 103 : CONS (V)); \ 104} \ 105struct __hack 106 107/* 108 * Atomic compare and set, used by the mutex functions 109 * 110 * if (*dst == exp) *dst = src (all 32 bit words) 111 * 112 * Returns 0 on failure, non-zero on success 113 */ 114 115static __inline int 116atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 117{ 118 int res = exp; 119 120 __asm __volatile ( 121 " " __XSTRING(MPLOCKED) " " 122 " cmpxchgl %1,%2 ; " 123 " setz %%al ; " 124 " movzbl %%al,%0 ; " 125 "1: " 126 "# atomic_cmpset_int" 127 : "+a" (res) /* 0 (result) */ 128 : "r" (src), /* 1 */ 129 "m" (*(dst)) /* 2 */ 130 : "memory"); 131 132 return (res); 133} 134 135static __inline int 136atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src) 137{ 138 long res = exp; 139 140 __asm __volatile ( 141 " " __XSTRING(MPLOCKED) " " 142 " cmpxchgq %1,%2 ; " 143 " setz %%al ; " 144 " movzbq %%al,%0 ; " 145 "1: " 146 "# atomic_cmpset_long" 147 : "+a" (res) /* 0 (result) */ 148 : "r" (src), /* 1 */ 149 "m" (*(dst)) /* 2 */ 150 : "memory"); 151 152 return (res); 153} 154 155#if defined(_KERNEL) && !defined(SMP) 156 157/* 158 * We assume that a = b will do atomic loads and stores. However, on a 159 * PentiumPro or higher, reads may pass writes, so for that case we have 160 * to use a serializing instruction (i.e. with LOCK) to do the load in 161 * SMP kernels. For UP kernels, however, the cache of the single processor 162 * is always consistent, so we don't need any memory barriers. 163 */ 164#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 165static __inline u_##TYPE \ 166atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 167{ \ 168 return (*p); \ 169} \ 170 \ 171static __inline void \ 172atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 173{ \ 174 *p = v; \ 175} \ 176struct __hack 177 178#else /* defined(SMP) */ 179 180#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 181static __inline u_##TYPE \ 182atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 183{ \ 184 u_##TYPE res; \ 185 \ 186 __asm __volatile(__XSTRING(MPLOCKED) LOP \ 187 : "=a" (res), /* 0 (result) */\ 188 "+m" (*p) /* 1 */ \ 189 : : "memory"); \ 190 \ 191 return (res); \ 192} \ 193 \ 194/* \ 195 * The XCHG instruction asserts LOCK automagically. \ 196 */ \ 197static __inline void \ 198atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 199{ \ 200 __asm __volatile(SOP \ 201 : "+m" (*p), /* 0 */ \ 202 "+r" (v) /* 1 */ \ 203 : : "memory"); \ 204} \ 205struct __hack 206 207#endif /* SMP */ 208 209#endif /* KLD_MODULE || !(__GNUCLIKE_ASM && __CC_SUPPORTS___INLINE) */ 210 211ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); 212ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); 213ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); 214ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); 215 216ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); 217ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); 218ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); 219ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); 220 221ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); 222ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); 223ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); 224ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); 225 226ATOMIC_ASM(set, long, "orq %1,%0", "ir", v); 227ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v); 228ATOMIC_ASM(add, long, "addq %1,%0", "ir", v); 229ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v); 230 231ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0"); 232ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0"); 233ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0"); 234ATOMIC_STORE_LOAD(long, "cmpxchgq %0,%1", "xchgq %1,%0"); 235 236#undef ATOMIC_ASM 237#undef ATOMIC_STORE_LOAD 238 239#if !defined(WANT_FUNCTIONS) 240 241/* Read the current value and store a zero in the destination. */ 242#if defined(__GNUCLIKE_ASM) && defined(__CC_SUPPORTS___INLINE) 243 244static __inline u_int 245atomic_readandclear_int(volatile u_int *addr) 246{ 247 u_int result; 248 249 __asm __volatile ( 250 " xorl %0,%0 ; " 251 " xchgl %1,%0 ; " 252 "# atomic_readandclear_int" 253 : "=&r" (result) /* 0 (result) */ 254 : "m" (*addr)); /* 1 (addr) */ 255 256 return (result); 257} 258 259static __inline u_long 260atomic_readandclear_long(volatile u_long *addr) 261{ 262 u_long result; 263 264 __asm __volatile ( 265 " xorq %0,%0 ; " 266 " xchgq %1,%0 ; " 267 "# atomic_readandclear_long" 268 : "=&r" (result) /* 0 (result) */ 269 : "m" (*addr)); /* 1 (addr) */ 270 271 return (result); 272} 273 274#else /* !(__GNUCLIKE_ASM && __CC_SUPPORTS___INLINE) */ 275 276u_int atomic_readandclear_int(volatile u_int *); 277u_long atomic_readandclear_long(volatile u_long *); 278 279#endif /* __GNUCLIKE_ASM && __CC_SUPPORTS___INLINE */ 280 281/* Acquire and release variants are identical to the normal ones. */ 282#define atomic_set_acq_char atomic_set_char 283#define atomic_set_rel_char atomic_set_char 284#define atomic_clear_acq_char atomic_clear_char 285#define atomic_clear_rel_char atomic_clear_char 286#define atomic_add_acq_char atomic_add_char 287#define atomic_add_rel_char atomic_add_char 288#define atomic_subtract_acq_char atomic_subtract_char 289#define atomic_subtract_rel_char atomic_subtract_char 290 291#define atomic_set_acq_short atomic_set_short 292#define atomic_set_rel_short atomic_set_short 293#define atomic_clear_acq_short atomic_clear_short 294#define atomic_clear_rel_short atomic_clear_short 295#define atomic_add_acq_short atomic_add_short 296#define atomic_add_rel_short atomic_add_short 297#define atomic_subtract_acq_short atomic_subtract_short 298#define atomic_subtract_rel_short atomic_subtract_short 299 300#define atomic_set_acq_int atomic_set_int 301#define atomic_set_rel_int atomic_set_int 302#define atomic_clear_acq_int atomic_clear_int 303#define atomic_clear_rel_int atomic_clear_int 304#define atomic_add_acq_int atomic_add_int 305#define atomic_add_rel_int atomic_add_int 306#define atomic_subtract_acq_int atomic_subtract_int 307#define atomic_subtract_rel_int atomic_subtract_int 308#define atomic_cmpset_acq_int atomic_cmpset_int 309#define atomic_cmpset_rel_int atomic_cmpset_int 310 311#define atomic_set_acq_long atomic_set_long 312#define atomic_set_rel_long atomic_set_long 313#define atomic_clear_acq_long atomic_clear_long 314#define atomic_clear_rel_long atomic_clear_long 315#define atomic_add_acq_long atomic_add_long 316#define atomic_add_rel_long atomic_add_long 317#define atomic_subtract_acq_long atomic_subtract_long 318#define atomic_subtract_rel_long atomic_subtract_long 319#define atomic_cmpset_acq_long atomic_cmpset_long 320#define atomic_cmpset_rel_long atomic_cmpset_long 321 322/* Operations on 8-bit bytes. */ 323#define atomic_set_8 atomic_set_char 324#define atomic_set_acq_8 atomic_set_acq_char 325#define atomic_set_rel_8 atomic_set_rel_char 326#define atomic_clear_8 atomic_clear_char 327#define atomic_clear_acq_8 atomic_clear_acq_char 328#define atomic_clear_rel_8 atomic_clear_rel_char 329#define atomic_add_8 atomic_add_char 330#define atomic_add_acq_8 atomic_add_acq_char 331#define atomic_add_rel_8 atomic_add_rel_char 332#define atomic_subtract_8 atomic_subtract_char 333#define atomic_subtract_acq_8 atomic_subtract_acq_char 334#define atomic_subtract_rel_8 atomic_subtract_rel_char 335#define atomic_load_acq_8 atomic_load_acq_char 336#define atomic_store_rel_8 atomic_store_rel_char 337 338/* Operations on 16-bit words. */ 339#define atomic_set_16 atomic_set_short 340#define atomic_set_acq_16 atomic_set_acq_short 341#define atomic_set_rel_16 atomic_set_rel_short 342#define atomic_clear_16 atomic_clear_short 343#define atomic_clear_acq_16 atomic_clear_acq_short 344#define atomic_clear_rel_16 atomic_clear_rel_short 345#define atomic_add_16 atomic_add_short 346#define atomic_add_acq_16 atomic_add_acq_short 347#define atomic_add_rel_16 atomic_add_rel_short 348#define atomic_subtract_16 atomic_subtract_short 349#define atomic_subtract_acq_16 atomic_subtract_acq_short 350#define atomic_subtract_rel_16 atomic_subtract_rel_short 351#define atomic_load_acq_16 atomic_load_acq_short 352#define atomic_store_rel_16 atomic_store_rel_short 353 354/* Operations on 32-bit double words. */ 355#define atomic_set_32 atomic_set_int 356#define atomic_set_acq_32 atomic_set_acq_int 357#define atomic_set_rel_32 atomic_set_rel_int 358#define atomic_clear_32 atomic_clear_int 359#define atomic_clear_acq_32 atomic_clear_acq_int 360#define atomic_clear_rel_32 atomic_clear_rel_int 361#define atomic_add_32 atomic_add_int 362#define atomic_add_acq_32 atomic_add_acq_int 363#define atomic_add_rel_32 atomic_add_rel_int 364#define atomic_subtract_32 atomic_subtract_int 365#define atomic_subtract_acq_32 atomic_subtract_acq_int 366#define atomic_subtract_rel_32 atomic_subtract_rel_int 367#define atomic_load_acq_32 atomic_load_acq_int 368#define atomic_store_rel_32 atomic_store_rel_int 369#define atomic_cmpset_32 atomic_cmpset_int 370#define atomic_cmpset_acq_32 atomic_cmpset_acq_int 371#define atomic_cmpset_rel_32 atomic_cmpset_rel_int 372#define atomic_readandclear_32 atomic_readandclear_int 373 374/* Operations on pointers. */ 375#define atomic_set_ptr atomic_set_long 376#define atomic_set_acq_ptr atomic_set_acq_long 377#define atomic_set_rel_ptr atomic_set_rel_long 378#define atomic_clear_ptr atomic_clear_long 379#define atomic_clear_acq_ptr atomic_clear_acq_long 380#define atomic_clear_rel_ptr atomic_clear_rel_long 381#define atomic_add_ptr atomic_add_long 382#define atomic_add_acq_ptr atomic_add_acq_long 383#define atomic_add_rel_ptr atomic_add_rel_long 384#define atomic_subtract_ptr atomic_subtract_long 385#define atomic_subtract_acq_ptr atomic_subtract_acq_long 386#define atomic_subtract_rel_ptr atomic_subtract_rel_long 387#define atomic_load_acq_ptr atomic_load_acq_long 388#define atomic_store_rel_ptr atomic_store_rel_long 389#define atomic_cmpset_ptr atomic_cmpset_long 390#define atomic_cmpset_acq_ptr atomic_cmpset_acq_long 391#define atomic_cmpset_rel_ptr atomic_cmpset_rel_long 392#define atomic_readandclear_ptr atomic_readandclear_long 393 394#endif /* !defined(WANT_FUNCTIONS) */ 395#endif /* ! _MACHINE_ATOMIC_H_ */ 396