2 * Copyright (c) 1998 Doug Rabson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
28 #ifndef _MACHINE_ATOMIC_H_
29 #define _MACHINE_ATOMIC_H_
32 #error this file needs sys/cdefs.h as a prerequisite
35 #define mb() __asm __volatile("mfence;" : : : "memory")
36 #define wmb() __asm __volatile("sfence;" : : : "memory")
37 #define rmb() __asm __volatile("lfence;" : : : "memory")
40 * Various simple operations on memory, each of which is atomic in the
41 * presence of interrupts and multiple processors.
43 * atomic_set_char(P, V) (*(u_char *)(P) |= (V))
44 * atomic_clear_char(P, V) (*(u_char *)(P) &= ~(V))
45 * atomic_add_char(P, V) (*(u_char *)(P) += (V))
46 * atomic_subtract_char(P, V) (*(u_char *)(P) -= (V))
48 * atomic_set_short(P, V) (*(u_short *)(P) |= (V))
49 * atomic_clear_short(P, V) (*(u_short *)(P) &= ~(V))
50 * atomic_add_short(P, V) (*(u_short *)(P) += (V))
51 * atomic_subtract_short(P, V) (*(u_short *)(P) -= (V))
53 * atomic_set_int(P, V) (*(u_int *)(P) |= (V))
54 * atomic_clear_int(P, V) (*(u_int *)(P) &= ~(V))
55 * atomic_add_int(P, V) (*(u_int *)(P) += (V))
56 * atomic_subtract_int(P, V) (*(u_int *)(P) -= (V))
57 * atomic_readandclear_int(P) (return (*(u_int *)(P)); *(u_int *)(P) = 0;)
59 * atomic_set_long(P, V) (*(u_long *)(P) |= (V))
60 * atomic_clear_long(P, V) (*(u_long *)(P) &= ~(V))
61 * atomic_add_long(P, V) (*(u_long *)(P) += (V))
62 * atomic_subtract_long(P, V) (*(u_long *)(P) -= (V))
63 * atomic_readandclear_long(P) (return (*(u_long *)(P)); *(u_long *)(P) = 0;)
67 * The above functions are expanded inline in the statically-linked
68 * kernel. Lock prefixes are generated if an SMP kernel is being
71 * Kernel modules call real functions which are built into the kernel.
72 * This allows kernel modules to be portable between UP and SMP systems.
74 #if defined(KLD_MODULE) || !defined(__GNUCLIKE_ASM)
75 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
76 void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v); \
77 void atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
79 int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
80 int atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src);
81 u_int atomic_fetchadd_int(volatile u_int *p, u_int v);
82 u_long atomic_fetchadd_long(volatile u_long *p, u_long v);
84 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
85 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \
86 void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
88 #else /* !KLD_MODULE && __GNUCLIKE_ASM */
91 * For userland, always use lock prefixes so that the binaries will run
92 * on both SMP and !SMP systems.
94 #if defined(SMP) || !defined(_KERNEL)
95 #define MPLOCKED "lock ; "
101 * The assembly is volatilized to avoid code chunk removal by the compiler.
102 * GCC aggressively reorders operations and memory clobbering is necessary
103 * in order to avoid that for memory barriers.
105 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
106 static __inline void \
107 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
109 __asm __volatile(MPLOCKED OP \
111 : CONS (V), "m" (*p) \
115 static __inline void \
116 atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
118 __asm __volatile(MPLOCKED OP \
120 : CONS (V), "m" (*p) \
126 * Atomic compare and set, used by the mutex functions
128 * if (*dst == exp) *dst = src (all 32 bit words)
130 * Returns 0 on failure, non-zero on success
134 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
143 "# atomic_cmpset_int"
144 : "=a" (res), /* 0 */
155 atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src)
164 "# atomic_cmpset_long"
165 : "=a" (res), /* 0 */
176 * Atomically add the value of v to the integer pointed to by p and return
177 * the previous value of *p.
179 static __inline u_int
180 atomic_fetchadd_int(volatile u_int *p, u_int v)
186 "# atomic_fetchadd_int"
187 : "+r" (v), /* 0 (result) */
195 * Atomically add the value of v to the long integer pointed to by p and return
196 * the previous value of *p.
198 static __inline u_long
199 atomic_fetchadd_long(volatile u_long *p, u_long v)
205 "# atomic_fetchadd_long"
206 : "+r" (v), /* 0 (result) */
213 #if defined(_KERNEL) && !defined(SMP)
216 * We assume that a = b will do atomic loads and stores. However, on a
217 * PentiumPro or higher, reads may pass writes, so for that case we have
218 * to use a serializing instruction (i.e. with LOCK) to do the load in
219 * SMP kernels. For UP kernels, however, the cache of the single processor
220 * is always consistent, so we only need to take care of compiler.
222 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
223 static __inline u_##TYPE \
224 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
229 __asm __volatile ("" : : : "memory"); \
233 static __inline void \
234 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
236 __asm __volatile ("" : : : "memory"); \
241 #else /* !(_KERNEL && !SMP) */
243 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
244 static __inline u_##TYPE \
245 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
249 __asm __volatile(MPLOCKED LOP \
250 : "=a" (res), /* 0 */ \
259 * The XCHG instruction asserts LOCK automagically. \
261 static __inline void \
262 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
264 __asm __volatile(SOP \
265 : "=m" (*p), /* 0 */ \
272 #endif /* _KERNEL && !SMP */
274 #endif /* KLD_MODULE || !__GNUCLIKE_ASM */
276 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v);
277 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v);
278 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v);
279 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v);
281 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v);
282 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v);
283 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v);
284 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v);
286 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v);
287 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v);
288 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v);
289 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v);
291 ATOMIC_ASM(set, long, "orq %1,%0", "ir", v);
292 ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v);
293 ATOMIC_ASM(add, long, "addq %1,%0", "ir", v);
294 ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v);
296 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0");
297 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0");
298 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0");
299 ATOMIC_STORE_LOAD(long, "cmpxchgq %0,%1", "xchgq %1,%0");
302 #undef ATOMIC_STORE_LOAD
304 #ifndef WANT_FUNCTIONS
306 /* Read the current value and store a zero in the destination. */
307 #ifdef __GNUCLIKE_ASM
309 static __inline u_int
310 atomic_readandclear_int(volatile u_int *addr)
317 "# atomic_readandclear_int"
318 : "+r" (res), /* 0 */
325 static __inline u_long
326 atomic_readandclear_long(volatile u_long *addr)
333 "# atomic_readandclear_long"
334 : "+r" (res), /* 0 */
341 #else /* !__GNUCLIKE_ASM */
343 u_int atomic_readandclear_int(volatile u_int *addr);
344 u_long atomic_readandclear_long(volatile u_long *addr);
346 #endif /* __GNUCLIKE_ASM */
348 #define atomic_set_acq_char atomic_set_barr_char
349 #define atomic_set_rel_char atomic_set_barr_char
350 #define atomic_clear_acq_char atomic_clear_barr_char
351 #define atomic_clear_rel_char atomic_clear_barr_char
352 #define atomic_add_acq_char atomic_add_barr_char
353 #define atomic_add_rel_char atomic_add_barr_char
354 #define atomic_subtract_acq_char atomic_subtract_barr_char
355 #define atomic_subtract_rel_char atomic_subtract_barr_char
357 #define atomic_set_acq_short atomic_set_barr_short
358 #define atomic_set_rel_short atomic_set_barr_short
359 #define atomic_clear_acq_short atomic_clear_barr_short
360 #define atomic_clear_rel_short atomic_clear_barr_short
361 #define atomic_add_acq_short atomic_add_barr_short
362 #define atomic_add_rel_short atomic_add_barr_short
363 #define atomic_subtract_acq_short atomic_subtract_barr_short
364 #define atomic_subtract_rel_short atomic_subtract_barr_short
366 #define atomic_set_acq_int atomic_set_barr_int
367 #define atomic_set_rel_int atomic_set_barr_int
368 #define atomic_clear_acq_int atomic_clear_barr_int
369 #define atomic_clear_rel_int atomic_clear_barr_int
370 #define atomic_add_acq_int atomic_add_barr_int
371 #define atomic_add_rel_int atomic_add_barr_int
372 #define atomic_subtract_acq_int atomic_subtract_barr_int
373 #define atomic_subtract_rel_int atomic_subtract_barr_int
374 #define atomic_cmpset_acq_int atomic_cmpset_int
375 #define atomic_cmpset_rel_int atomic_cmpset_int
377 #define atomic_set_acq_long atomic_set_barr_long
378 #define atomic_set_rel_long atomic_set_barr_long
379 #define atomic_clear_acq_long atomic_clear_barr_long
380 #define atomic_clear_rel_long atomic_clear_barr_long
381 #define atomic_add_acq_long atomic_add_barr_long
382 #define atomic_add_rel_long atomic_add_barr_long
383 #define atomic_subtract_acq_long atomic_subtract_barr_long
384 #define atomic_subtract_rel_long atomic_subtract_barr_long
385 #define atomic_cmpset_acq_long atomic_cmpset_long
386 #define atomic_cmpset_rel_long atomic_cmpset_long
388 /* Operations on 8-bit bytes. */
389 #define atomic_set_8 atomic_set_char
390 #define atomic_set_acq_8 atomic_set_acq_char
391 #define atomic_set_rel_8 atomic_set_rel_char
392 #define atomic_clear_8 atomic_clear_char
393 #define atomic_clear_acq_8 atomic_clear_acq_char
394 #define atomic_clear_rel_8 atomic_clear_rel_char
395 #define atomic_add_8 atomic_add_char
396 #define atomic_add_acq_8 atomic_add_acq_char
397 #define atomic_add_rel_8 atomic_add_rel_char
398 #define atomic_subtract_8 atomic_subtract_char
399 #define atomic_subtract_acq_8 atomic_subtract_acq_char
400 #define atomic_subtract_rel_8 atomic_subtract_rel_char
401 #define atomic_load_acq_8 atomic_load_acq_char
402 #define atomic_store_rel_8 atomic_store_rel_char
404 /* Operations on 16-bit words. */
405 #define atomic_set_16 atomic_set_short
406 #define atomic_set_acq_16 atomic_set_acq_short
407 #define atomic_set_rel_16 atomic_set_rel_short
408 #define atomic_clear_16 atomic_clear_short
409 #define atomic_clear_acq_16 atomic_clear_acq_short
410 #define atomic_clear_rel_16 atomic_clear_rel_short
411 #define atomic_add_16 atomic_add_short
412 #define atomic_add_acq_16 atomic_add_acq_short
413 #define atomic_add_rel_16 atomic_add_rel_short
414 #define atomic_subtract_16 atomic_subtract_short
415 #define atomic_subtract_acq_16 atomic_subtract_acq_short
416 #define atomic_subtract_rel_16 atomic_subtract_rel_short
417 #define atomic_load_acq_16 atomic_load_acq_short
418 #define atomic_store_rel_16 atomic_store_rel_short
420 /* Operations on 32-bit double words. */
421 #define atomic_set_32 atomic_set_int
422 #define atomic_set_acq_32 atomic_set_acq_int
423 #define atomic_set_rel_32 atomic_set_rel_int
424 #define atomic_clear_32 atomic_clear_int
425 #define atomic_clear_acq_32 atomic_clear_acq_int
426 #define atomic_clear_rel_32 atomic_clear_rel_int
427 #define atomic_add_32 atomic_add_int
428 #define atomic_add_acq_32 atomic_add_acq_int
429 #define atomic_add_rel_32 atomic_add_rel_int
430 #define atomic_subtract_32 atomic_subtract_int
431 #define atomic_subtract_acq_32 atomic_subtract_acq_int
432 #define atomic_subtract_rel_32 atomic_subtract_rel_int
433 #define atomic_load_acq_32 atomic_load_acq_int
434 #define atomic_store_rel_32 atomic_store_rel_int
435 #define atomic_cmpset_32 atomic_cmpset_int
436 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int
437 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int
438 #define atomic_readandclear_32 atomic_readandclear_int
439 #define atomic_fetchadd_32 atomic_fetchadd_int
441 /* Operations on 64-bit quad words. */
442 #define atomic_set_64 atomic_set_long
443 #define atomic_set_acq_64 atomic_set_acq_long
444 #define atomic_set_rel_64 atomic_set_rel_long
445 #define atomic_clear_64 atomic_clear_long
446 #define atomic_clear_acq_64 atomic_clear_acq_long
447 #define atomic_clear_rel_64 atomic_clear_rel_long
448 #define atomic_add_64 atomic_add_long
449 #define atomic_add_acq_64 atomic_add_acq_long
450 #define atomic_add_rel_64 atomic_add_rel_long
451 #define atomic_subtract_64 atomic_subtract_long
452 #define atomic_subtract_acq_64 atomic_subtract_acq_long
453 #define atomic_subtract_rel_64 atomic_subtract_rel_long
454 #define atomic_load_acq_64 atomic_load_acq_long
455 #define atomic_store_rel_64 atomic_store_rel_long
456 #define atomic_cmpset_64 atomic_cmpset_long
457 #define atomic_cmpset_acq_64 atomic_cmpset_acq_long
458 #define atomic_cmpset_rel_64 atomic_cmpset_rel_long
459 #define atomic_readandclear_64 atomic_readandclear_long
461 /* Operations on pointers. */
462 #define atomic_set_ptr atomic_set_long
463 #define atomic_set_acq_ptr atomic_set_acq_long
464 #define atomic_set_rel_ptr atomic_set_rel_long
465 #define atomic_clear_ptr atomic_clear_long
466 #define atomic_clear_acq_ptr atomic_clear_acq_long
467 #define atomic_clear_rel_ptr atomic_clear_rel_long
468 #define atomic_add_ptr atomic_add_long
469 #define atomic_add_acq_ptr atomic_add_acq_long
470 #define atomic_add_rel_ptr atomic_add_rel_long
471 #define atomic_subtract_ptr atomic_subtract_long
472 #define atomic_subtract_acq_ptr atomic_subtract_acq_long
473 #define atomic_subtract_rel_ptr atomic_subtract_rel_long
474 #define atomic_load_acq_ptr atomic_load_acq_long
475 #define atomic_store_rel_ptr atomic_store_rel_long
476 #define atomic_cmpset_ptr atomic_cmpset_long
477 #define atomic_cmpset_acq_ptr atomic_cmpset_acq_long
478 #define atomic_cmpset_rel_ptr atomic_cmpset_rel_long
479 #define atomic_readandclear_ptr atomic_readandclear_long
481 #endif /* !WANT_FUNCTIONS */
483 #endif /* !_MACHINE_ATOMIC_H_ */