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 #ifndef _SYS_CDEFS_H_
32 #error this file needs sys/cdefs.h as a prerequisite
33 #endif
34
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")
38
39 /*
40 * Various simple operations on memory, each of which is atomic in the
41 * presence of interrupts and multiple processors.
42 *
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))
47 *
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))
52 *
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;)
58 *
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;)
64 */
65
66 /*
67 * The above functions are expanded inline in the statically-linked
68 * kernel. Lock prefixes are generated if an SMP kernel is being
69 * built.
70 *
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.
73 */
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)
78
79 int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
80 u_int atomic_fetchadd_int(volatile u_int *p, u_int v);
81
82 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
83 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \
84 void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
85
86 #else /* !KLD_MODULE && __GNUCLIKE_ASM */
87
88 /*
89 * For userland, always use lock prefixes so that the binaries will run
90 * on both SMP and !SMP systems.
91 */
92 #if defined(SMP) || !defined(_KERNEL)
93 #define MPLOCKED "lock ; "
94 #else
95 #define MPLOCKED
96 #endif
97
98 /*
99 * The assembly is volatilized to avoid code chunk removal by the compiler.
100 * GCC aggressively reorders operations and memory clobbering is necessary
101 * in order to avoid that for memory barriers.
102 */
103 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
104 static __inline void \
105 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
106 { \
107 __asm __volatile(MPLOCKED OP \
108 : "=m" (*p) \
109 : CONS (V), "m" (*p) \
110 : "cc"); \
111 } \
112 \
113 static __inline void \
114 atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
115 { \
116 __asm __volatile(MPLOCKED OP \
117 : "=m" (*p) \
118 : CONS (V), "m" (*p) \
119 : "memory", "cc"); \
120 } \
121 struct __hack
122
123 /*
124 * Atomic compare and set, used by the mutex functions
125 *
126 * if (*dst == exp) *dst = src (all 32 bit words)
127 *
128 * Returns 0 on failure, non-zero on success
129 */
130
131 #ifdef CPU_DISABLE_CMPXCHG
132
133 static __inline int
134 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
135 {
136 u_char res;
137
138 __asm __volatile(
139 " pushfl ; "
140 " cli ; "
141 " cmpl %3,%4 ; "
142 " jne 1f ; "
143 " movl %2,%1 ; "
144 "1: "
145 " sete %0 ; "
146 " popfl ; "
147 "# atomic_cmpset_int"
148 : "=q" (res), /* 0 */
149 "=m" (*dst) /* 1 */
150 : "r" (src), /* 2 */
151 "r" (exp), /* 3 */
152 "m" (*dst) /* 4 */
153 : "memory");
154
155 return (res);
156 }
157
158 #else /* !CPU_DISABLE_CMPXCHG */
159
160 static __inline int
161 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
162 {
163 u_char res;
164
165 __asm __volatile(
166 " " MPLOCKED " "
167 " cmpxchgl %2,%1 ; "
168 " sete %0 ; "
169 "1: "
170 "# atomic_cmpset_int"
171 : "=a" (res), /* 0 */
172 "=m" (*dst) /* 1 */
173 : "r" (src), /* 2 */
174 "a" (exp), /* 3 */
175 "m" (*dst) /* 4 */
176 : "memory", "cc");
177
178 return (res);
179 }
180
181 #endif /* CPU_DISABLE_CMPXCHG */
182
183 /*
184 * Atomically add the value of v to the integer pointed to by p and return
185 * the previous value of *p.
186 */
187 static __inline u_int
188 atomic_fetchadd_int(volatile u_int *p, u_int v)
189 {
190
191 __asm __volatile(
192 " " MPLOCKED " "
193 " xaddl %0, %1 ; "
194 "# atomic_fetchadd_int"
195 : "+r" (v), /* 0 (result) */
196 "=m" (*p) /* 1 */
197 : "m" (*p) /* 2 */
198 : "cc");
199 return (v);
200 }
201
202 #if defined(_KERNEL) && !defined(SMP)
203
204 /*
205 * We assume that a = b will do atomic loads and stores. However, on a
206 * PentiumPro or higher, reads may pass writes, so for that case we have
207 * to use a serializing instruction (i.e. with LOCK) to do the load in
208 * SMP kernels. For UP kernels, however, the cache of the single processor
209 * is always consistent, so we only need to take care of compiler.
210 */
211 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
212 static __inline u_##TYPE \
213 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
214 { \
215 u_##TYPE tmp; \
216 \
217 tmp = *p; \
218 __asm __volatile("" : : : "memory"); \
219 return (tmp); \
220 } \
221 \
222 static __inline void \
223 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
224 { \
225 __asm __volatile("" : : : "memory"); \
226 *p = v; \
227 } \
228 struct __hack
229
230 #else /* !(_KERNEL && !SMP) */
231
232 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
233 static __inline u_##TYPE \
234 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
235 { \
236 u_##TYPE res; \
237 \
238 __asm __volatile(MPLOCKED LOP \
239 : "=a" (res), /* 0 */ \
240 "=m" (*p) /* 1 */ \
241 : "m" (*p) /* 2 */ \
242 : "memory", "cc"); \
243 \
244 return (res); \
245 } \
246 \
247 /* \
248 * The XCHG instruction asserts LOCK automagically. \
249 */ \
250 static __inline void \
251 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
252 { \
253 __asm __volatile(SOP \
254 : "=m" (*p), /* 0 */ \
255 "+r" (v) /* 1 */ \
256 : "m" (*p) /* 2 */ \
257 : "memory"); \
258 } \
259 struct __hack
260
261 #endif /* _KERNEL && !SMP */
262
263 #endif /* KLD_MODULE || !__GNUCLIKE_ASM */
264
265 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v);
266 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v);
267 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v);
268 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v);
269
270 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v);
271 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v);
272 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v);
273 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v);
274
275 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v);
276 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v);
277 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v);
278 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v);
279
280 ATOMIC_ASM(set, long, "orl %1,%0", "ir", v);
281 ATOMIC_ASM(clear, long, "andl %1,%0", "ir", ~v);
282 ATOMIC_ASM(add, long, "addl %1,%0", "ir", v);
283 ATOMIC_ASM(subtract, long, "subl %1,%0", "ir", v);
284
285 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0");
286 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0");
287 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0");
288 ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0");
289
290 #undef ATOMIC_ASM
291 #undef ATOMIC_STORE_LOAD
292
293 #ifndef WANT_FUNCTIONS
294
295 static __inline int
296 atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src)
297 {
298
299 return (atomic_cmpset_int((volatile u_int *)dst, (u_int)exp,
300 (u_int)src));
301 }
302
303 static __inline u_long
304 atomic_fetchadd_long(volatile u_long *p, u_long v)
305 {
306
307 return (atomic_fetchadd_int((volatile u_int *)p, (u_int)v));
308 }
309
310 /* Read the current value and store a zero in the destination. */
311 #ifdef __GNUCLIKE_ASM
312
313 static __inline u_int
314 atomic_readandclear_int(volatile u_int *addr)
315 {
316 u_int res;
317
318 res = 0;
319 __asm __volatile(
320 " xchgl %1,%0 ; "
321 "# atomic_readandclear_int"
322 : "+r" (res), /* 0 */
323 "=m" (*addr) /* 1 */
324 : "m" (*addr));
325
326 return (res);
327 }
328
329 static __inline u_long
330 atomic_readandclear_long(volatile u_long *addr)
331 {
332 u_long res;
333
334 res = 0;
335 __asm __volatile(
336 " xchgl %1,%0 ; "
337 "# atomic_readandclear_long"
338 : "+r" (res), /* 0 */
339 "=m" (*addr) /* 1 */
340 : "m" (*addr));
341
342 return (res);
343 }
344
345 #else /* !__GNUCLIKE_ASM */
346
347 u_int atomic_readandclear_int(volatile u_int *addr);
348 u_long atomic_readandclear_long(volatile u_long *addr);
349
350 #endif /* __GNUCLIKE_ASM */
351
352 #define atomic_set_acq_char atomic_set_barr_char
353 #define atomic_set_rel_char atomic_set_barr_char
354 #define atomic_clear_acq_char atomic_clear_barr_char
355 #define atomic_clear_rel_char atomic_clear_barr_char
356 #define atomic_add_acq_char atomic_add_barr_char
357 #define atomic_add_rel_char atomic_add_barr_char
358 #define atomic_subtract_acq_char atomic_subtract_barr_char
359 #define atomic_subtract_rel_char atomic_subtract_barr_char
360
361 #define atomic_set_acq_short atomic_set_barr_short
362 #define atomic_set_rel_short atomic_set_barr_short
363 #define atomic_clear_acq_short atomic_clear_barr_short
364 #define atomic_clear_rel_short atomic_clear_barr_short
365 #define atomic_add_acq_short atomic_add_barr_short
366 #define atomic_add_rel_short atomic_add_barr_short
367 #define atomic_subtract_acq_short atomic_subtract_barr_short
368 #define atomic_subtract_rel_short atomic_subtract_barr_short
369
370 #define atomic_set_acq_int atomic_set_barr_int
371 #define atomic_set_rel_int atomic_set_barr_int
372 #define atomic_clear_acq_int atomic_clear_barr_int
373 #define atomic_clear_rel_int atomic_clear_barr_int
374 #define atomic_add_acq_int atomic_add_barr_int
375 #define atomic_add_rel_int atomic_add_barr_int
376 #define atomic_subtract_acq_int atomic_subtract_barr_int
377 #define atomic_subtract_rel_int atomic_subtract_barr_int
378 #define atomic_cmpset_acq_int atomic_cmpset_int
379 #define atomic_cmpset_rel_int atomic_cmpset_int
380
381 #define atomic_set_acq_long atomic_set_barr_long
382 #define atomic_set_rel_long atomic_set_barr_long
383 #define atomic_clear_acq_long atomic_clear_barr_long
384 #define atomic_clear_rel_long atomic_clear_barr_long
385 #define atomic_add_acq_long atomic_add_barr_long
386 #define atomic_add_rel_long atomic_add_barr_long
387 #define atomic_subtract_acq_long atomic_subtract_barr_long
388 #define atomic_subtract_rel_long atomic_subtract_barr_long
389 #define atomic_cmpset_acq_long atomic_cmpset_long
390 #define atomic_cmpset_rel_long atomic_cmpset_long
391
392 /* Operations on 8-bit bytes. */
393 #define atomic_set_8 atomic_set_char
394 #define atomic_set_acq_8 atomic_set_acq_char
395 #define atomic_set_rel_8 atomic_set_rel_char
396 #define atomic_clear_8 atomic_clear_char
397 #define atomic_clear_acq_8 atomic_clear_acq_char
398 #define atomic_clear_rel_8 atomic_clear_rel_char
399 #define atomic_add_8 atomic_add_char
400 #define atomic_add_acq_8 atomic_add_acq_char
401 #define atomic_add_rel_8 atomic_add_rel_char
402 #define atomic_subtract_8 atomic_subtract_char
403 #define atomic_subtract_acq_8 atomic_subtract_acq_char
404 #define atomic_subtract_rel_8 atomic_subtract_rel_char
405 #define atomic_load_acq_8 atomic_load_acq_char
406 #define atomic_store_rel_8 atomic_store_rel_char
407
408 /* Operations on 16-bit words. */
409 #define atomic_set_16 atomic_set_short
410 #define atomic_set_acq_16 atomic_set_acq_short
411 #define atomic_set_rel_16 atomic_set_rel_short
412 #define atomic_clear_16 atomic_clear_short
413 #define atomic_clear_acq_16 atomic_clear_acq_short
414 #define atomic_clear_rel_16 atomic_clear_rel_short
415 #define atomic_add_16 atomic_add_short
416 #define atomic_add_acq_16 atomic_add_acq_short
417 #define atomic_add_rel_16 atomic_add_rel_short
418 #define atomic_subtract_16 atomic_subtract_short
419 #define atomic_subtract_acq_16 atomic_subtract_acq_short
420 #define atomic_subtract_rel_16 atomic_subtract_rel_short
421 #define atomic_load_acq_16 atomic_load_acq_short
422 #define atomic_store_rel_16 atomic_store_rel_short
423
424 /* Operations on 32-bit double words. */
425 #define atomic_set_32 atomic_set_int
426 #define atomic_set_acq_32 atomic_set_acq_int
427 #define atomic_set_rel_32 atomic_set_rel_int
428 #define atomic_clear_32 atomic_clear_int
429 #define atomic_clear_acq_32 atomic_clear_acq_int
430 #define atomic_clear_rel_32 atomic_clear_rel_int
431 #define atomic_add_32 atomic_add_int
432 #define atomic_add_acq_32 atomic_add_acq_int
433 #define atomic_add_rel_32 atomic_add_rel_int
434 #define atomic_subtract_32 atomic_subtract_int
435 #define atomic_subtract_acq_32 atomic_subtract_acq_int
436 #define atomic_subtract_rel_32 atomic_subtract_rel_int
437 #define atomic_load_acq_32 atomic_load_acq_int
438 #define atomic_store_rel_32 atomic_store_rel_int
439 #define atomic_cmpset_32 atomic_cmpset_int
440 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int
441 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int
442 #define atomic_readandclear_32 atomic_readandclear_int
443 #define atomic_fetchadd_32 atomic_fetchadd_int
444
445 /* Operations on pointers. */
446 #define atomic_set_ptr(p, v) \
447 atomic_set_int((volatile u_int *)(p), (u_int)(v))
448 #define atomic_set_acq_ptr(p, v) \
449 atomic_set_acq_int((volatile u_int *)(p), (u_int)(v))
450 #define atomic_set_rel_ptr(p, v) \
451 atomic_set_rel_int((volatile u_int *)(p), (u_int)(v))
452 #define atomic_clear_ptr(p, v) \
453 atomic_clear_int((volatile u_int *)(p), (u_int)(v))
454 #define atomic_clear_acq_ptr(p, v) \
455 atomic_clear_acq_int((volatile u_int *)(p), (u_int)(v))
456 #define atomic_clear_rel_ptr(p, v) \
457 atomic_clear_rel_int((volatile u_int *)(p), (u_int)(v))
458 #define atomic_add_ptr(p, v) \
459 atomic_add_int((volatile u_int *)(p), (u_int)(v))
460 #define atomic_add_acq_ptr(p, v) \
461 atomic_add_acq_int((volatile u_int *)(p), (u_int)(v))
462 #define atomic_add_rel_ptr(p, v) \
463 atomic_add_rel_int((volatile u_int *)(p), (u_int)(v))
464 #define atomic_subtract_ptr(p, v) \
465 atomic_subtract_int((volatile u_int *)(p), (u_int)(v))
466 #define atomic_subtract_acq_ptr(p, v) \
467 atomic_subtract_acq_int((volatile u_int *)(p), (u_int)(v))
468 #define atomic_subtract_rel_ptr(p, v) \
469 atomic_subtract_rel_int((volatile u_int *)(p), (u_int)(v))
470 #define atomic_load_acq_ptr(p) \
471 atomic_load_acq_int((volatile u_int *)(p))
472 #define atomic_store_rel_ptr(p, v) \
473 atomic_store_rel_int((volatile u_int *)(p), (v))
474 #define atomic_cmpset_ptr(dst, old, new) \
475 atomic_cmpset_int((volatile u_int *)(dst), (u_int)(old), (u_int)(new))
476 #define atomic_cmpset_acq_ptr(dst, old, new) \
477 atomic_cmpset_acq_int((volatile u_int *)(dst), (u_int)(old), \
478 (u_int)(new))
479 #define atomic_cmpset_rel_ptr(dst, old, new) \
480 atomic_cmpset_rel_int((volatile u_int *)(dst), (u_int)(old), \
481 (u_int)(new))
482 #define atomic_readandclear_ptr(p) \
483 atomic_readandclear_int((volatile u_int *)(p))
484
485 #endif /* !WANT_FUNCTIONS */
486
487 #endif /* !_MACHINE_ATOMIC_H_ */
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