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)
78 int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
79 int atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src);
80 u_int atomic_fetchadd_int(volatile u_int *p, u_int v);
81 u_long atomic_fetchadd_long(volatile u_long *p, u_long v);
83 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
84 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \
85 void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
87 #else /* !KLD_MODULE && __GNUCLIKE_ASM */
90 * For userland, always use lock prefixes so that the binaries will run
91 * on both SMP and !SMP systems.
93 #if defined(SMP) || !defined(_KERNEL)
94 #define MPLOCKED "lock ; "
100 * The assembly is volatilized to demark potential before-and-after side
101 * effects if an interrupt or SMP collision were to occur.
103 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
104 static __inline void \
105 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
107 __asm __volatile(MPLOCKED OP \
109 : CONS (V), "m" (*p)); \
114 * Atomic compare and set, used by the mutex functions
116 * if (*dst == exp) *dst = src (all 32 bit words)
118 * Returns 0 on failure, non-zero on success
122 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
131 "# atomic_cmpset_int"
132 : "=a" (res), /* 0 */
143 atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src)
152 "# atomic_cmpset_long"
153 : "=a" (res), /* 0 */
164 * Atomically add the value of v to the integer pointed to by p and return
165 * the previous value of *p.
167 static __inline u_int
168 atomic_fetchadd_int(volatile u_int *p, u_int v)
174 "# atomic_fetchadd_int"
175 : "+r" (v), /* 0 (result) */
183 * Atomically add the value of v to the long integer pointed to by p and return
184 * the previous value of *p.
186 static __inline u_long
187 atomic_fetchadd_long(volatile u_long *p, u_long v)
193 "# atomic_fetchadd_long"
194 : "+r" (v), /* 0 (result) */
201 #if defined(_KERNEL) && !defined(SMP)
204 * We assume that a = b will do atomic loads and stores. However, on a
205 * PentiumPro or higher, reads may pass writes, so for that case we have
206 * to use a serializing instruction (i.e. with LOCK) to do the load in
207 * SMP kernels. For UP kernels, however, the cache of the single processor
208 * is always consistent, so we don't need any memory barriers.
210 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
211 static __inline u_##TYPE \
212 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
217 static __inline void \
218 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
224 #else /* !(_KERNEL && !SMP) */
226 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
227 static __inline u_##TYPE \
228 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
232 __asm __volatile(MPLOCKED LOP \
233 : "=a" (res), /* 0 */ \
242 * The XCHG instruction asserts LOCK automagically. \
244 static __inline void \
245 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
247 __asm __volatile(SOP \
248 : "=m" (*p), /* 0 */ \
250 : "m" (*p)); /* 2 */ \
254 #endif /* _KERNEL && !SMP */
256 #endif /* KLD_MODULE || !__GNUCLIKE_ASM */
258 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v);
259 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v);
260 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v);
261 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v);
263 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v);
264 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v);
265 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v);
266 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v);
268 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v);
269 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v);
270 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v);
271 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v);
273 ATOMIC_ASM(set, long, "orq %1,%0", "ir", v);
274 ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v);
275 ATOMIC_ASM(add, long, "addq %1,%0", "ir", v);
276 ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v);
278 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0");
279 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0");
280 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0");
281 ATOMIC_STORE_LOAD(long, "cmpxchgq %0,%1", "xchgq %1,%0");
284 #undef ATOMIC_STORE_LOAD
286 #ifndef WANT_FUNCTIONS
288 /* Read the current value and store a zero in the destination. */
289 #ifdef __GNUCLIKE_ASM
291 static __inline u_int
292 atomic_readandclear_int(volatile u_int *addr)
299 "# atomic_readandclear_int"
300 : "+r" (res), /* 0 */
307 static __inline u_long
308 atomic_readandclear_long(volatile u_long *addr)
315 "# atomic_readandclear_long"
316 : "+r" (res), /* 0 */
323 #else /* !__GNUCLIKE_ASM */
325 u_int atomic_readandclear_int(volatile u_int *addr);
326 u_long atomic_readandclear_long(volatile u_long *addr);
328 #endif /* __GNUCLIKE_ASM */
330 /* Acquire and release variants are identical to the normal ones. */
331 #define atomic_set_acq_char atomic_set_char
332 #define atomic_set_rel_char atomic_set_char
333 #define atomic_clear_acq_char atomic_clear_char
334 #define atomic_clear_rel_char atomic_clear_char
335 #define atomic_add_acq_char atomic_add_char
336 #define atomic_add_rel_char atomic_add_char
337 #define atomic_subtract_acq_char atomic_subtract_char
338 #define atomic_subtract_rel_char atomic_subtract_char
340 #define atomic_set_acq_short atomic_set_short
341 #define atomic_set_rel_short atomic_set_short
342 #define atomic_clear_acq_short atomic_clear_short
343 #define atomic_clear_rel_short atomic_clear_short
344 #define atomic_add_acq_short atomic_add_short
345 #define atomic_add_rel_short atomic_add_short
346 #define atomic_subtract_acq_short atomic_subtract_short
347 #define atomic_subtract_rel_short atomic_subtract_short
349 #define atomic_set_acq_int atomic_set_int
350 #define atomic_set_rel_int atomic_set_int
351 #define atomic_clear_acq_int atomic_clear_int
352 #define atomic_clear_rel_int atomic_clear_int
353 #define atomic_add_acq_int atomic_add_int
354 #define atomic_add_rel_int atomic_add_int
355 #define atomic_subtract_acq_int atomic_subtract_int
356 #define atomic_subtract_rel_int atomic_subtract_int
357 #define atomic_cmpset_acq_int atomic_cmpset_int
358 #define atomic_cmpset_rel_int atomic_cmpset_int
360 #define atomic_set_acq_long atomic_set_long
361 #define atomic_set_rel_long atomic_set_long
362 #define atomic_clear_acq_long atomic_clear_long
363 #define atomic_clear_rel_long atomic_clear_long
364 #define atomic_add_acq_long atomic_add_long
365 #define atomic_add_rel_long atomic_add_long
366 #define atomic_subtract_acq_long atomic_subtract_long
367 #define atomic_subtract_rel_long atomic_subtract_long
368 #define atomic_cmpset_acq_long atomic_cmpset_long
369 #define atomic_cmpset_rel_long atomic_cmpset_long
371 /* Operations on 8-bit bytes. */
372 #define atomic_set_8 atomic_set_char
373 #define atomic_set_acq_8 atomic_set_acq_char
374 #define atomic_set_rel_8 atomic_set_rel_char
375 #define atomic_clear_8 atomic_clear_char
376 #define atomic_clear_acq_8 atomic_clear_acq_char
377 #define atomic_clear_rel_8 atomic_clear_rel_char
378 #define atomic_add_8 atomic_add_char
379 #define atomic_add_acq_8 atomic_add_acq_char
380 #define atomic_add_rel_8 atomic_add_rel_char
381 #define atomic_subtract_8 atomic_subtract_char
382 #define atomic_subtract_acq_8 atomic_subtract_acq_char
383 #define atomic_subtract_rel_8 atomic_subtract_rel_char
384 #define atomic_load_acq_8 atomic_load_acq_char
385 #define atomic_store_rel_8 atomic_store_rel_char
387 /* Operations on 16-bit words. */
388 #define atomic_set_16 atomic_set_short
389 #define atomic_set_acq_16 atomic_set_acq_short
390 #define atomic_set_rel_16 atomic_set_rel_short
391 #define atomic_clear_16 atomic_clear_short
392 #define atomic_clear_acq_16 atomic_clear_acq_short
393 #define atomic_clear_rel_16 atomic_clear_rel_short
394 #define atomic_add_16 atomic_add_short
395 #define atomic_add_acq_16 atomic_add_acq_short
396 #define atomic_add_rel_16 atomic_add_rel_short
397 #define atomic_subtract_16 atomic_subtract_short
398 #define atomic_subtract_acq_16 atomic_subtract_acq_short
399 #define atomic_subtract_rel_16 atomic_subtract_rel_short
400 #define atomic_load_acq_16 atomic_load_acq_short
401 #define atomic_store_rel_16 atomic_store_rel_short
403 /* Operations on 32-bit double words. */
404 #define atomic_set_32 atomic_set_int
405 #define atomic_set_acq_32 atomic_set_acq_int
406 #define atomic_set_rel_32 atomic_set_rel_int
407 #define atomic_clear_32 atomic_clear_int
408 #define atomic_clear_acq_32 atomic_clear_acq_int
409 #define atomic_clear_rel_32 atomic_clear_rel_int
410 #define atomic_add_32 atomic_add_int
411 #define atomic_add_acq_32 atomic_add_acq_int
412 #define atomic_add_rel_32 atomic_add_rel_int
413 #define atomic_subtract_32 atomic_subtract_int
414 #define atomic_subtract_acq_32 atomic_subtract_acq_int
415 #define atomic_subtract_rel_32 atomic_subtract_rel_int
416 #define atomic_load_acq_32 atomic_load_acq_int
417 #define atomic_store_rel_32 atomic_store_rel_int
418 #define atomic_cmpset_32 atomic_cmpset_int
419 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int
420 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int
421 #define atomic_readandclear_32 atomic_readandclear_int
422 #define atomic_fetchadd_32 atomic_fetchadd_int
424 /* Operations on 64-bit quad words. */
425 #define atomic_set_64 atomic_set_long
426 #define atomic_set_acq_64 atomic_set_acq_long
427 #define atomic_set_rel_64 atomic_set_rel_long
428 #define atomic_clear_64 atomic_clear_long
429 #define atomic_clear_acq_64 atomic_clear_acq_long
430 #define atomic_clear_rel_64 atomic_clear_rel_long
431 #define atomic_add_64 atomic_add_long
432 #define atomic_add_acq_64 atomic_add_acq_long
433 #define atomic_add_rel_64 atomic_add_rel_long
434 #define atomic_subtract_64 atomic_subtract_long
435 #define atomic_subtract_acq_64 atomic_subtract_acq_long
436 #define atomic_subtract_rel_64 atomic_subtract_rel_long
437 #define atomic_load_acq_64 atomic_load_acq_long
438 #define atomic_store_rel_64 atomic_store_rel_long
439 #define atomic_cmpset_64 atomic_cmpset_long
440 #define atomic_cmpset_acq_64 atomic_cmpset_acq_long
441 #define atomic_cmpset_rel_64 atomic_cmpset_rel_long
442 #define atomic_readandclear_64 atomic_readandclear_long
444 /* Operations on pointers. */
445 #define atomic_set_ptr atomic_set_long
446 #define atomic_set_acq_ptr atomic_set_acq_long
447 #define atomic_set_rel_ptr atomic_set_rel_long
448 #define atomic_clear_ptr atomic_clear_long
449 #define atomic_clear_acq_ptr atomic_clear_acq_long
450 #define atomic_clear_rel_ptr atomic_clear_rel_long
451 #define atomic_add_ptr atomic_add_long
452 #define atomic_add_acq_ptr atomic_add_acq_long
453 #define atomic_add_rel_ptr atomic_add_rel_long
454 #define atomic_subtract_ptr atomic_subtract_long
455 #define atomic_subtract_acq_ptr atomic_subtract_acq_long
456 #define atomic_subtract_rel_ptr atomic_subtract_rel_long
457 #define atomic_load_acq_ptr atomic_load_acq_long
458 #define atomic_store_rel_ptr atomic_store_rel_long
459 #define atomic_cmpset_ptr atomic_cmpset_long
460 #define atomic_cmpset_acq_ptr atomic_cmpset_acq_long
461 #define atomic_cmpset_rel_ptr atomic_cmpset_rel_long
462 #define atomic_readandclear_ptr atomic_readandclear_long
464 #endif /* !WANT_FUNCTIONS */
466 #endif /* !_MACHINE_ATOMIC_H_ */