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, 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 #if defined(LOCORE) 84 #define MPLOCKED lock ; 85 #else /* !LOCORE */ 86 #define MPLOCKED "lock ; " 87 #endif /* LOCORE */ 88 #else /* SMP || !_KERNEL */ 89 #define MPLOCKED 90 #endif /* SMP || !_KERNEL */ 91 92 #if !defined(LOCORE) 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, V) \ 98 static __inline void \ 99 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 100 { \ 101 __asm __volatile(MPLOCKED OP \ 102 : "=m" (*p) \ 103 : "0" (*p), "ir" (V)); \ 104 } 105 106 /* 107 * Atomic compare and set, used by the mutex functions 108 * 109 * if (*dst == exp) *dst = src (all 32 bit words) 110 * 111 * Returns 0 on failure, non-zero on success 112 */ 113 114 #if defined(I386_CPU) 115 static __inline int 116 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 117 { 118 int res = exp; 119 120 __asm __volatile( 121 " pushfl ; " 122 " cli ; " 123 " cmpl %1,%3 ; " 124 " jne 1f ; " 125 " movl %2,%3 ; " 126 "1: " 127 " sete %%al; " 128 " movzbl %%al,%0 ; " 129 " popfl ; " 130 "# atomic_cmpset_int" 131 : "=a" (res) /* 0 (result) */ 132 : "0" (exp), /* 1 */ 133 "r" (src), /* 2 */ 134 "m" (*(dst)) /* 3 */ 135 : "memory"); 136 137 return (res); 138 } 139 #else /* defined(I386_CPU) */ 140 static __inline int 141 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src) 142 { 143 int res = exp; 144 145 __asm __volatile ( 146 " " MPLOCKED " " 147 " cmpxchgl %2,%3 ; " 148 " setz %%al ; " 149 " movzbl %%al,%0 ; " 150 "1: " 151 "# atomic_cmpset_int" 152 : "=a" (res) /* 0 (result) */ 153 : "0" (exp), /* 1 */ 154 "r" (src), /* 2 */ 155 "m" (*(dst)) /* 3 */ 156 : "memory"); 157 158 return (res); 159 } 160 #endif /* defined(I386_CPU) */ 161 162 #if defined(I386_CPU) 163 /* 164 * We assume that a = b will do atomic loads and stores. 165 * 166 * XXX: This is _NOT_ safe on a P6 or higher because it does not guarantee 167 * memory ordering. These should only be used on a 386. 168 */ 169 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 170 static __inline u_##TYPE \ 171 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 172 { \ 173 return (*p); \ 174 } \ 175 \ 176 static __inline void \ 177 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 178 { \ 179 *p = v; \ 180 __asm __volatile("" : : : "memory"); \ 181 } 182 #else 183 184 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ 185 static __inline u_##TYPE \ 186 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ 187 { \ 188 u_##TYPE res; \ 189 \ 190 __asm __volatile(MPLOCKED LOP \ 191 : "=a" (res), /* 0 (result) */\ 192 "+m" (*p) /* 1 */ \ 193 : : "cc", "memory"); \ 194 \ 195 return (res); \ 196 } \ 197 \ 198 /* \ 199 * The XCHG instruction asserts LOCK automagically. \ 200 */ \ 201 static __inline void \ 202 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ 203 { \ 204 __asm __volatile(SOP \ 205 : "+m" (*p), /* 0 */ \ 206 "+r" (v) /* 1 */ \ 207 : : "memory"); \ 208 } 209 #endif /* defined(I386_CPU) */ 210 #endif /* !defined(LOCORE) */ 211 #endif /* KLD_MODULE */ 212 213 #if !defined(LOCORE) 214 ATOMIC_ASM(set, char, "orb %b2,%0", v) 215 ATOMIC_ASM(clear, char, "andb %b2,%0", ~v) 216 ATOMIC_ASM(add, char, "addb %b2,%0", v) 217 ATOMIC_ASM(subtract, char, "subb %b2,%0", v) 218 219 ATOMIC_ASM(set, short, "orw %w2,%0", v) 220 ATOMIC_ASM(clear, short, "andw %w2,%0", ~v) 221 ATOMIC_ASM(add, short, "addw %w2,%0", v) 222 ATOMIC_ASM(subtract, short, "subw %w2,%0", v) 223 224 ATOMIC_ASM(set, int, "orl %2,%0", v) 225 ATOMIC_ASM(clear, int, "andl %2,%0", ~v) 226 ATOMIC_ASM(add, int, "addl %2,%0", v) 227 ATOMIC_ASM(subtract, int, "subl %2,%0", v) 228 229 ATOMIC_ASM(set, long, "orl %2,%0", v) 230 ATOMIC_ASM(clear, long, "andl %2,%0", ~v) 231 ATOMIC_ASM(add, long, "addl %2,%0", v) 232 ATOMIC_ASM(subtract, long, "subl %2,%0", v) 233 234 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0") 235 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0") 236 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0") 237 ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0") 238 239 #undef ATOMIC_ASM 240 #undef ATOMIC_STORE_LOAD 241 242 #define atomic_set_acq_char atomic_set_char 243 #define atomic_set_rel_char atomic_set_char 244 #define atomic_clear_acq_char atomic_clear_char 245 #define atomic_clear_rel_char atomic_clear_char 246 #define atomic_add_acq_char atomic_add_char 247 #define atomic_add_rel_char atomic_add_char 248 #define atomic_subtract_acq_char atomic_subtract_char 249 #define atomic_subtract_rel_char atomic_subtract_char 250 251 #define atomic_set_acq_short atomic_set_short 252 #define atomic_set_rel_short atomic_set_short 253 #define atomic_clear_acq_short atomic_clear_short 254 #define atomic_clear_rel_short atomic_clear_short 255 #define atomic_add_acq_short atomic_add_short 256 #define atomic_add_rel_short atomic_add_short 257 #define atomic_subtract_acq_short atomic_subtract_short 258 #define atomic_subtract_rel_short atomic_subtract_short 259 260 #define atomic_set_acq_int atomic_set_int 261 #define atomic_set_rel_int atomic_set_int 262 #define atomic_clear_acq_int atomic_clear_int 263 #define atomic_clear_rel_int atomic_clear_int 264 #define atomic_add_acq_int atomic_add_int 265 #define atomic_add_rel_int atomic_add_int 266 #define atomic_subtract_acq_int atomic_subtract_int 267 #define atomic_subtract_rel_int atomic_subtract_int 268 #define atomic_cmpset_acq_int atomic_cmpset_int 269 #define atomic_cmpset_rel_int atomic_cmpset_int 270 271 #define atomic_set_acq_long atomic_set_long 272 #define atomic_set_rel_long atomic_set_long 273 #define atomic_clear_acq_long atomic_clear_long 274 #define atomic_clear_rel_long atomic_clear_long 275 #define atomic_add_acq_long atomic_add_long 276 #define atomic_add_rel_long atomic_add_long 277 #define atomic_subtract_acq_long atomic_subtract_long 278 #define atomic_subtract_rel_long atomic_subtract_long 279 #define atomic_cmpset_long atomic_cmpset_int 280 #define atomic_cmpset_acq_long atomic_cmpset_acq_int 281 #define atomic_cmpset_rel_long atomic_cmpset_rel_int 282 283 #define atomic_cmpset_acq_ptr atomic_cmpset_ptr 284 #define atomic_cmpset_rel_ptr atomic_cmpset_ptr 285 286 #define atomic_set_8 atomic_set_char 287 #define atomic_set_acq_8 atomic_set_acq_char 288 #define atomic_set_rel_8 atomic_set_rel_char 289 #define atomic_clear_8 atomic_clear_char 290 #define atomic_clear_acq_8 atomic_clear_acq_char 291 #define atomic_clear_rel_8 atomic_clear_rel_char 292 #define atomic_add_8 atomic_add_char 293 #define atomic_add_acq_8 atomic_add_acq_char 294 #define atomic_add_rel_8 atomic_add_rel_char 295 #define atomic_subtract_8 atomic_subtract_char 296 #define atomic_subtract_acq_8 atomic_subtract_acq_char 297 #define atomic_subtract_rel_8 atomic_subtract_rel_char 298 #define atomic_load_acq_8 atomic_load_acq_char 299 #define atomic_store_rel_8 atomic_store_rel_char 300 301 #define atomic_set_16 atomic_set_short 302 #define atomic_set_acq_16 atomic_set_acq_short 303 #define atomic_set_rel_16 atomic_set_rel_short 304 #define atomic_clear_16 atomic_clear_short 305 #define atomic_clear_acq_16 atomic_clear_acq_short 306 #define atomic_clear_rel_16 atomic_clear_rel_short 307 #define atomic_add_16 atomic_add_short 308 #define atomic_add_acq_16 atomic_add_acq_short 309 #define atomic_add_rel_16 atomic_add_rel_short 310 #define atomic_subtract_16 atomic_subtract_short 311 #define atomic_subtract_acq_16 atomic_subtract_acq_short 312 #define atomic_subtract_rel_16 atomic_subtract_rel_short 313 #define atomic_load_acq_16 atomic_load_acq_short 314 #define atomic_store_rel_16 atomic_store_rel_short 315 316 #define atomic_set_32 atomic_set_int 317 #define atomic_set_acq_32 atomic_set_acq_int 318 #define atomic_set_rel_32 atomic_set_rel_int 319 #define atomic_clear_32 atomic_clear_int 320 #define atomic_clear_acq_32 atomic_clear_acq_int 321 #define atomic_clear_rel_32 atomic_clear_rel_int 322 #define atomic_add_32 atomic_add_int 323 #define atomic_add_acq_32 atomic_add_acq_int 324 #define atomic_add_rel_32 atomic_add_rel_int 325 #define atomic_subtract_32 atomic_subtract_int 326 #define atomic_subtract_acq_32 atomic_subtract_acq_int 327 #define atomic_subtract_rel_32 atomic_subtract_rel_int 328 #define atomic_load_acq_32 atomic_load_acq_int 329 #define atomic_store_rel_32 atomic_store_rel_int 330 #define atomic_cmpset_32 atomic_cmpset_int 331 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int 332 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int 333 #define atomic_readandclear_32 atomic_readandclear_int 334 335 #if !defined(WANT_FUNCTIONS) 336 static __inline int 337 atomic_cmpset_ptr(volatile void *dst, void *exp, void *src) 338 { 339 340 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, 341 (u_int)src)); 342 } 343 344 static __inline void * 345 atomic_load_acq_ptr(volatile void *p) 346 { 347 return (void *)atomic_load_acq_int((volatile u_int *)p); 348 } 349 350 static __inline void 351 atomic_store_rel_ptr(volatile void *p, void *v) 352 { 353 atomic_store_rel_int((volatile u_int *)p, (u_int)v); 354 } 355 356 #define ATOMIC_PTR(NAME) \ 357 static __inline void \ 358 atomic_##NAME##_ptr(volatile void *p, uintptr_t v) \ 359 { \ 360 atomic_##NAME##_int((volatile u_int *)p, v); \ 361 } \ 362 \ 363 static __inline void \ 364 atomic_##NAME##_acq_ptr(volatile void *p, uintptr_t v) \ 365 { \ 366 atomic_##NAME##_acq_int((volatile u_int *)p, v);\ 367 } \ 368 \ 369 static __inline void \ 370 atomic_##NAME##_rel_ptr(volatile void *p, uintptr_t v) \ 371 { \ 372 atomic_##NAME##_rel_int((volatile u_int *)p, v);\ 373 } 374 375 ATOMIC_PTR(set) 376 ATOMIC_PTR(clear) 377 ATOMIC_PTR(add) 378 ATOMIC_PTR(subtract) 379 380 #undef ATOMIC_PTR 381 382 static __inline u_int 383 atomic_readandclear_int(volatile u_int *addr) 384 { 385 u_int result; 386 387 __asm __volatile ( 388 " xorl %0,%0 ; " 389 " xchgl %1,%0 ; " 390 "# atomic_readandclear_int" 391 : "=&r" (result) /* 0 (result) */ 392 : "m" (*addr)); /* 1 (addr) */ 393 394 return (result); 395 } 396 397 static __inline u_long 398 atomic_readandclear_long(volatile u_long *addr) 399 { 400 u_long result; 401 402 __asm __volatile ( 403 " xorl %0,%0 ; " 404 " xchgl %1,%0 ; " 405 "# atomic_readandclear_int" 406 : "=&r" (result) /* 0 (result) */ 407 : "m" (*addr)); /* 1 (addr) */ 408 409 return (result); 410 } 411 #endif /* !defined(WANT_FUNCTIONS) */ 412 #endif /* !defined(LOCORE) */ 413 #endif /* ! _MACHINE_ATOMIC_H_ */ 414