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("lock; addl $0,(%%esp)" : : : "memory")
36 #define wmb() __asm __volatile("lock; addl $0,(%%esp)" : : : "memory")
37 #define rmb() __asm __volatile("lock; addl $0,(%%esp)" : : : "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 u_int atomic_fetchadd_int(volatile u_int *p, u_int v);
81 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
82 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \
83 void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
85 #else /* !KLD_MODULE && __GNUCLIKE_ASM */
88 * For userland, always use lock prefixes so that the binaries will run
89 * on both SMP and !SMP systems.
91 #if defined(SMP) || !defined(_KERNEL)
92 #define MPLOCKED "lock ; "
98 * The assembly is volatilized to demark potential before-and-after side
99 * effects if an interrupt or SMP collision were to occur.
101 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
102 static __inline void \
103 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
105 __asm __volatile(MPLOCKED OP \
107 : CONS (V), "m" (*p)); \
112 * Atomic compare and set, used by the mutex functions
114 * if (*dst == exp) *dst = src (all 32 bit words)
116 * Returns 0 on failure, non-zero on success
119 #ifdef CPU_DISABLE_CMPXCHG
122 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
135 "# atomic_cmpset_int"
136 : "=q" (res), /* 0 */
146 #else /* !CPU_DISABLE_CMPXCHG */
149 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
158 "# atomic_cmpset_int"
159 : "=a" (res), /* 0 */
169 #endif /* CPU_DISABLE_CMPXCHG */
172 * Atomically add the value of v to the integer pointed to by p and return
173 * the previous value of *p.
175 static __inline u_int
176 atomic_fetchadd_int(volatile u_int *p, u_int v)
182 "# atomic_fetchadd_int"
183 : "+r" (v), /* 0 (result) */
190 #if defined(_KERNEL) && !defined(SMP)
193 * We assume that a = b will do atomic loads and stores. However, on a
194 * PentiumPro or higher, reads may pass writes, so for that case we have
195 * to use a serializing instruction (i.e. with LOCK) to do the load in
196 * SMP kernels. For UP kernels, however, the cache of the single processor
197 * is always consistent, so we don't need any memory barriers.
199 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
200 static __inline u_##TYPE \
201 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
206 static __inline void \
207 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
213 #else /* !(_KERNEL && !SMP) */
215 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
216 static __inline u_##TYPE \
217 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
221 __asm __volatile(MPLOCKED LOP \
222 : "=a" (res), /* 0 */ \
231 * The XCHG instruction asserts LOCK automagically. \
233 static __inline void \
234 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
236 __asm __volatile(SOP \
237 : "=m" (*p), /* 0 */ \
239 : "m" (*p)); /* 2 */ \
243 #endif /* _KERNEL && !SMP */
245 #endif /* KLD_MODULE || !__GNUCLIKE_ASM */
247 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v);
248 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v);
249 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v);
250 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v);
252 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v);
253 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v);
254 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v);
255 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v);
257 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v);
258 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v);
259 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v);
260 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v);
262 ATOMIC_ASM(set, long, "orl %1,%0", "ir", v);
263 ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v);
264 ATOMIC_ASM(add, long, "addl %1,%0", "ir", v);
265 ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v);
267 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0");
268 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0");
269 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0");
270 ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0");
273 #undef ATOMIC_STORE_LOAD
275 #ifndef WANT_FUNCTIONS
278 atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src)
281 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp,
285 static __inline u_long
286 atomic_fetchadd_long(volatile u_long *p, u_long v)
289 return (atomic_fetchadd_int((volatile u_int *)p, (u_int)v));
292 /* Read the current value and store a zero in the destination. */
293 #ifdef __GNUCLIKE_ASM
295 static __inline u_int
296 atomic_readandclear_int(volatile u_int *addr)
303 "# atomic_readandclear_int"
304 : "+r" (res), /* 0 */
311 static __inline u_long
312 atomic_readandclear_long(volatile u_long *addr)
319 "# atomic_readandclear_long"
320 : "+r" (res), /* 0 */
327 #else /* !__GNUCLIKE_ASM */
329 u_int atomic_readandclear_int(volatile u_int *addr);
330 u_long atomic_readandclear_long(volatile u_long *addr);
332 #endif /* __GNUCLIKE_ASM */
334 /* Acquire and release variants are identical to the normal ones. */
335 #define atomic_set_acq_char atomic_set_char
336 #define atomic_set_rel_char atomic_set_char
337 #define atomic_clear_acq_char atomic_clear_char
338 #define atomic_clear_rel_char atomic_clear_char
339 #define atomic_add_acq_char atomic_add_char
340 #define atomic_add_rel_char atomic_add_char
341 #define atomic_subtract_acq_char atomic_subtract_char
342 #define atomic_subtract_rel_char atomic_subtract_char
344 #define atomic_set_acq_short atomic_set_short
345 #define atomic_set_rel_short atomic_set_short
346 #define atomic_clear_acq_short atomic_clear_short
347 #define atomic_clear_rel_short atomic_clear_short
348 #define atomic_add_acq_short atomic_add_short
349 #define atomic_add_rel_short atomic_add_short
350 #define atomic_subtract_acq_short atomic_subtract_short
351 #define atomic_subtract_rel_short atomic_subtract_short
353 #define atomic_set_acq_int atomic_set_int
354 #define atomic_set_rel_int atomic_set_int
355 #define atomic_clear_acq_int atomic_clear_int
356 #define atomic_clear_rel_int atomic_clear_int
357 #define atomic_add_acq_int atomic_add_int
358 #define atomic_add_rel_int atomic_add_int
359 #define atomic_subtract_acq_int atomic_subtract_int
360 #define atomic_subtract_rel_int atomic_subtract_int
361 #define atomic_cmpset_acq_int atomic_cmpset_int
362 #define atomic_cmpset_rel_int atomic_cmpset_int
364 #define atomic_set_acq_long atomic_set_long
365 #define atomic_set_rel_long atomic_set_long
366 #define atomic_clear_acq_long atomic_clear_long
367 #define atomic_clear_rel_long atomic_clear_long
368 #define atomic_add_acq_long atomic_add_long
369 #define atomic_add_rel_long atomic_add_long
370 #define atomic_subtract_acq_long atomic_subtract_long
371 #define atomic_subtract_rel_long atomic_subtract_long
372 #define atomic_cmpset_acq_long atomic_cmpset_long
373 #define atomic_cmpset_rel_long atomic_cmpset_long
375 /* Operations on 8-bit bytes. */
376 #define atomic_set_8 atomic_set_char
377 #define atomic_set_acq_8 atomic_set_acq_char
378 #define atomic_set_rel_8 atomic_set_rel_char
379 #define atomic_clear_8 atomic_clear_char
380 #define atomic_clear_acq_8 atomic_clear_acq_char
381 #define atomic_clear_rel_8 atomic_clear_rel_char
382 #define atomic_add_8 atomic_add_char
383 #define atomic_add_acq_8 atomic_add_acq_char
384 #define atomic_add_rel_8 atomic_add_rel_char
385 #define atomic_subtract_8 atomic_subtract_char
386 #define atomic_subtract_acq_8 atomic_subtract_acq_char
387 #define atomic_subtract_rel_8 atomic_subtract_rel_char
388 #define atomic_load_acq_8 atomic_load_acq_char
389 #define atomic_store_rel_8 atomic_store_rel_char
391 /* Operations on 16-bit words. */
392 #define atomic_set_16 atomic_set_short
393 #define atomic_set_acq_16 atomic_set_acq_short
394 #define atomic_set_rel_16 atomic_set_rel_short
395 #define atomic_clear_16 atomic_clear_short
396 #define atomic_clear_acq_16 atomic_clear_acq_short
397 #define atomic_clear_rel_16 atomic_clear_rel_short
398 #define atomic_add_16 atomic_add_short
399 #define atomic_add_acq_16 atomic_add_acq_short
400 #define atomic_add_rel_16 atomic_add_rel_short
401 #define atomic_subtract_16 atomic_subtract_short
402 #define atomic_subtract_acq_16 atomic_subtract_acq_short
403 #define atomic_subtract_rel_16 atomic_subtract_rel_short
404 #define atomic_load_acq_16 atomic_load_acq_short
405 #define atomic_store_rel_16 atomic_store_rel_short
407 /* Operations on 32-bit double words. */
408 #define atomic_set_32 atomic_set_int
409 #define atomic_set_acq_32 atomic_set_acq_int
410 #define atomic_set_rel_32 atomic_set_rel_int
411 #define atomic_clear_32 atomic_clear_int
412 #define atomic_clear_acq_32 atomic_clear_acq_int
413 #define atomic_clear_rel_32 atomic_clear_rel_int
414 #define atomic_add_32 atomic_add_int
415 #define atomic_add_acq_32 atomic_add_acq_int
416 #define atomic_add_rel_32 atomic_add_rel_int
417 #define atomic_subtract_32 atomic_subtract_int
418 #define atomic_subtract_acq_32 atomic_subtract_acq_int
419 #define atomic_subtract_rel_32 atomic_subtract_rel_int
420 #define atomic_load_acq_32 atomic_load_acq_int
421 #define atomic_store_rel_32 atomic_store_rel_int
422 #define atomic_cmpset_32 atomic_cmpset_int
423 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int
424 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int
425 #define atomic_readandclear_32 atomic_readandclear_int
426 #define atomic_fetchadd_32 atomic_fetchadd_int
428 /* Operations on pointers. */
429 #define atomic_set_ptr(p, v) \
430 atomic_set_int((volatile u_int *)(p), (u_int)(v))
431 #define atomic_set_acq_ptr(p, v) \
432 atomic_set_acq_int((volatile u_int *)(p), (u_int)(v))
433 #define atomic_set_rel_ptr(p, v) \
434 atomic_set_rel_int((volatile u_int *)(p), (u_int)(v))
435 #define atomic_clear_ptr(p, v) \
436 atomic_clear_int((volatile u_int *)(p), (u_int)(v))
437 #define atomic_clear_acq_ptr(p, v) \
438 atomic_clear_acq_int((volatile u_int *)(p), (u_int)(v))
439 #define atomic_clear_rel_ptr(p, v) \
440 atomic_clear_rel_int((volatile u_int *)(p), (u_int)(v))
441 #define atomic_add_ptr(p, v) \
442 atomic_add_int((volatile u_int *)(p), (u_int)(v))
443 #define atomic_add_acq_ptr(p, v) \
444 atomic_add_acq_int((volatile u_int *)(p), (u_int)(v))
445 #define atomic_add_rel_ptr(p, v) \
446 atomic_add_rel_int((volatile u_int *)(p), (u_int)(v))
447 #define atomic_subtract_ptr(p, v) \
448 atomic_subtract_int((volatile u_int *)(p), (u_int)(v))
449 #define atomic_subtract_acq_ptr(p, v) \
450 atomic_subtract_acq_int((volatile u_int *)(p), (u_int)(v))
451 #define atomic_subtract_rel_ptr(p, v) \
452 atomic_subtract_rel_int((volatile u_int *)(p), (u_int)(v))
453 #define atomic_load_acq_ptr(p) \
454 atomic_load_acq_int((volatile u_int *)(p))
455 #define atomic_store_rel_ptr(p, v) \
456 atomic_store_rel_int((volatile u_int *)(p), (v))
457 #define atomic_cmpset_ptr(dst, old, new) \
458 atomic_cmpset_int((volatile u_int *)(dst), (u_int)(old), (u_int)(new))
459 #define atomic_cmpset_acq_ptr(dst, old, new) \
460 atomic_cmpset_acq_int((volatile u_int *)(dst), (u_int)(old), \
462 #define atomic_cmpset_rel_ptr(dst, old, new) \
463 atomic_cmpset_rel_int((volatile u_int *)(dst), (u_int)(old), \
465 #define atomic_readandclear_ptr(p) \
466 atomic_readandclear_int((volatile u_int *)(p))
468 #endif /* !WANT_FUNCTIONS */
470 #endif /* !_MACHINE_ATOMIC_H_ */