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 /* 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) \ 68 void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v); 69 70 int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src); 71 72 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 73 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ 74 void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v); 75 76 #else /* !KLD_MODULE */ 77 78 /* 79 * For userland, assume the SMP case and use lock prefixes so that 80 * the binaries will run on both types of systems. 81 */ 82 #if defined(SMP) || !defined(_KERNEL) 83 #define MPLOCKED "lock ; " 84 #else 85 #define MPLOCKED 86 #endif 87 88 /* 89 * The assembly is volatilized to demark potential before-and-after side 90 * effects if an interrupt or SMP collision were to occur. 91 */ 92 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ 93 static __inline void \ 94 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 95 { \ 96 __asm __volatile(MPLOCKED OP \ 97 : "+m" (*p) \ 98 : CONS (V)); \ 99 } 100 101 /* 102 * Atomic compare and set, used by the mutex functions 103 * 104 * if (*dst == exp) *dst = src (all 32 bit words) 105 * 106 * Returns 0 on failure, non-zero on success 107 */ 108 109 #if defined(I386_CPU) 110 static __inline int 111 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 112 { 113 int res = exp; 114 115 __asm __volatile( 116 " pushfl ; " 117 " cli ; " 118 " cmpl %0,%2 ; " 119 " jne 1f ; " 120 " movl %1,%2 ; " 121 "1: " 122 " sete %%al; " 123 " movzbl %%al,%0 ; " 124 " popfl ; " 125 "# atomic_cmpset_int" 126 : "+a" (res) /* 0 (result) */ 127 : "r" (src), /* 1 */ 128 "m" (*(dst)) /* 2 */ 129 : "memory"); 130 131 return (res); 132 } 133 #else /* defined(I386_CPU) */ 134 static __inline int 135 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 136 { 137 int res = exp; 138 139 __asm __volatile ( 140 " " MPLOCKED " " 141 " cmpxchgl %1,%2 ; " 142 " setz %%al ; " 143 " movzbl %%al,%0 ; " 144 "1: " 145 "# atomic_cmpset_int" 146 : "+a" (res) /* 0 (result) */ 147 : "r" (src), /* 1 */ 148 "m" (*(dst)) /* 2 */ 149 : "memory"); 150 151 return (res); 152 } 153 #endif /* defined(I386_CPU) */ 154 155 #if defined(I386_CPU) 156 /* 157 * We assume that a = b will do atomic loads and stores. 158 * 159 * XXX: This is _NOT_ safe on a P6 or higher because it does not guarantee 160 * memory ordering. These should only be used on a 386. 161 */ 162 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 163 static __inline u_##TYPE \ 164 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 165 { \ 166 return (*p); \ 167 } \ 168 \ 169 static __inline void \ 170 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 171 { \ 172 *p = v; \ 173 __asm __volatile("" : : : "memory"); \ 174 } 175 #else 176 177 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 178 static __inline u_##TYPE \ 179 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 180 { \ 181 u_##TYPE res; \ 182 \ 183 __asm __volatile(MPLOCKED LOP \ 184 : "=a" (res), /* 0 (result) */\ 185 "+m" (*p) /* 1 */ \ 186 : : "memory"); \ 187 \ 188 return (res); \ 189 } \ 190 \ 191 /* \ 192 * The XCHG instruction asserts LOCK automagically. \ 193 */ \ 194 static __inline void \ 195 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 196 { \ 197 __asm __volatile(SOP \ 198 : "+m" (*p), /* 0 */ \ 199 "+r" (v) /* 1 */ \ 200 : : "memory"); \ 201 } 202 #endif /* defined(I386_CPU) */ 203 #endif /* KLD_MODULE */ 204 205 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v) 206 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v) 207 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v) 208 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v) 209 210 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v) 211 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v) 212 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v) 213 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v) 214 215 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v) 216 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v) 217 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v) 218 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v) 219 220 ATOMIC_ASM(set, long, "orl %1,%0", "ir", v) 221 ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v) 222 ATOMIC_ASM(add, long, "addl %1,%0", "ir", v) 223 ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v) 224 225 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0") 226 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0") 227 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0") 228 ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0") 229 230 #undef ATOMIC_ASM 231 #undef ATOMIC_STORE_LOAD 232 233 #define atomic_set_acq_char atomic_set_char 234 #define atomic_set_rel_char atomic_set_char 235 #define atomic_clear_acq_char atomic_clear_char 236 #define atomic_clear_rel_char atomic_clear_char 237 #define atomic_add_acq_char atomic_add_char 238 #define atomic_add_rel_char atomic_add_char 239 #define atomic_subtract_acq_char atomic_subtract_char 240 #define atomic_subtract_rel_char atomic_subtract_char 241 242 #define atomic_set_acq_short atomic_set_short 243 #define atomic_set_rel_short atomic_set_short 244 #define atomic_clear_acq_short atomic_clear_short 245 #define atomic_clear_rel_short atomic_clear_short 246 #define atomic_add_acq_short atomic_add_short 247 #define atomic_add_rel_short atomic_add_short 248 #define atomic_subtract_acq_short atomic_subtract_short 249 #define atomic_subtract_rel_short atomic_subtract_short 250 251 #define atomic_set_acq_int atomic_set_int 252 #define atomic_set_rel_int atomic_set_int 253 #define atomic_clear_acq_int atomic_clear_int 254 #define atomic_clear_rel_int atomic_clear_int 255 #define atomic_add_acq_int atomic_add_int 256 #define atomic_add_rel_int atomic_add_int 257 #define atomic_subtract_acq_int atomic_subtract_int 258 #define atomic_subtract_rel_int atomic_subtract_int 259 #define atomic_cmpset_acq_int atomic_cmpset_int 260 #define atomic_cmpset_rel_int atomic_cmpset_int 261 262 #define atomic_set_acq_long atomic_set_long 263 #define atomic_set_rel_long atomic_set_long 264 #define atomic_clear_acq_long atomic_clear_long 265 #define atomic_clear_rel_long atomic_clear_long 266 #define atomic_add_acq_long atomic_add_long 267 #define atomic_add_rel_long atomic_add_long 268 #define atomic_subtract_acq_long atomic_subtract_long 269 #define atomic_subtract_rel_long atomic_subtract_long 270 #define atomic_cmpset_long atomic_cmpset_int 271 #define atomic_cmpset_acq_long atomic_cmpset_acq_int 272 #define atomic_cmpset_rel_long atomic_cmpset_rel_int 273 274 #define atomic_cmpset_acq_ptr atomic_cmpset_ptr 275 #define atomic_cmpset_rel_ptr atomic_cmpset_ptr 276 277 #define atomic_set_8 atomic_set_char 278 #define atomic_set_acq_8 atomic_set_acq_char 279 #define atomic_set_rel_8 atomic_set_rel_char 280 #define atomic_clear_8 atomic_clear_char 281 #define atomic_clear_acq_8 atomic_clear_acq_char 282 #define atomic_clear_rel_8 atomic_clear_rel_char 283 #define atomic_add_8 atomic_add_char 284 #define atomic_add_acq_8 atomic_add_acq_char 285 #define atomic_add_rel_8 atomic_add_rel_char 286 #define atomic_subtract_8 atomic_subtract_char 287 #define atomic_subtract_acq_8 atomic_subtract_acq_char 288 #define atomic_subtract_rel_8 atomic_subtract_rel_char 289 #define atomic_load_acq_8 atomic_load_acq_char 290 #define atomic_store_rel_8 atomic_store_rel_char 291 292 #define atomic_set_16 atomic_set_short 293 #define atomic_set_acq_16 atomic_set_acq_short 294 #define atomic_set_rel_16 atomic_set_rel_short 295 #define atomic_clear_16 atomic_clear_short 296 #define atomic_clear_acq_16 atomic_clear_acq_short 297 #define atomic_clear_rel_16 atomic_clear_rel_short 298 #define atomic_add_16 atomic_add_short 299 #define atomic_add_acq_16 atomic_add_acq_short 300 #define atomic_add_rel_16 atomic_add_rel_short 301 #define atomic_subtract_16 atomic_subtract_short 302 #define atomic_subtract_acq_16 atomic_subtract_acq_short 303 #define atomic_subtract_rel_16 atomic_subtract_rel_short 304 #define atomic_load_acq_16 atomic_load_acq_short 305 #define atomic_store_rel_16 atomic_store_rel_short 306 307 #define atomic_set_32 atomic_set_int 308 #define atomic_set_acq_32 atomic_set_acq_int 309 #define atomic_set_rel_32 atomic_set_rel_int 310 #define atomic_clear_32 atomic_clear_int 311 #define atomic_clear_acq_32 atomic_clear_acq_int 312 #define atomic_clear_rel_32 atomic_clear_rel_int 313 #define atomic_add_32 atomic_add_int 314 #define atomic_add_acq_32 atomic_add_acq_int 315 #define atomic_add_rel_32 atomic_add_rel_int 316 #define atomic_subtract_32 atomic_subtract_int 317 #define atomic_subtract_acq_32 atomic_subtract_acq_int 318 #define atomic_subtract_rel_32 atomic_subtract_rel_int 319 #define atomic_load_acq_32 atomic_load_acq_int 320 #define atomic_store_rel_32 atomic_store_rel_int 321 #define atomic_cmpset_32 atomic_cmpset_int 322 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int 323 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int 324 #define atomic_readandclear_32 atomic_readandclear_int 325 326 #if !defined(WANT_FUNCTIONS) 327 static __inline int 328 atomic_cmpset_ptr(volatile void *dst, void *exp, void *src) 329 { 330 331 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 332 (u_int)src)); 333 } 334 335 static __inline void * 336 atomic_load_acq_ptr(volatile void *p) 337 { 338 return (void *)atomic_load_acq_int((volatile u_int *)p); 339 } 340 341 static __inline void 342 atomic_store_rel_ptr(volatile void *p, void *v) 343 { 344 atomic_store_rel_int((volatile u_int *)p, (u_int)v); 345 } 346 347 #define ATOMIC_PTR(NAME) \ 348 static __inline void \ 349 atomic_##NAME##_ptr(volatile void *p, uintptr_t v) \ 350 { \ 351 atomic_##NAME##_int((volatile u_int *)p, v); \ 352 } \ 353 \ 354 static __inline void \ 355 atomic_##NAME##_acq_ptr(volatile void *p, uintptr_t v) \ 356 { \ 357 atomic_##NAME##_acq_int((volatile u_int *)p, v);\ 358 } \ 359 \ 360 static __inline void \ 361 atomic_##NAME##_rel_ptr(volatile void *p, uintptr_t v) \ 362 { \ 363 atomic_##NAME##_rel_int((volatile u_int *)p, v);\ 364 } 365 366 ATOMIC_PTR(set) 367 ATOMIC_PTR(clear) 368 ATOMIC_PTR(add) 369 ATOMIC_PTR(subtract) 370 371 #undef ATOMIC_PTR 372 373 static __inline u_int 374 atomic_readandclear_int(volatile u_int *addr) 375 { 376 u_int result; 377 378 __asm __volatile ( 379 " xorl %0,%0 ; " 380 " xchgl %1,%0 ; " 381 "# atomic_readandclear_int" 382 : "=&r" (result) /* 0 (result) */ 383 : "m" (*addr)); /* 1 (addr) */ 384 385 return (result); 386 } 387 388 static __inline u_long 389 atomic_readandclear_long(volatile u_long *addr) 390 { 391 u_long result; 392 393 __asm __volatile ( 394 " xorl %0,%0 ; " 395 " xchgl %1,%0 ; " 396 "# atomic_readandclear_int" 397 : "=&r" (result) /* 0 (result) */ 398 : "m" (*addr)); /* 1 (addr) */ 399 400 return (result); 401 } 402 #endif /* !defined(WANT_FUNCTIONS) */ 403 #endif /* ! _MACHINE_ATOMIC_H_ */ 404