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 /*
36 * Various simple operations on memory, each of which is atomic in the
37 * presence of interrupts and multiple processors.
38 *
39 * atomic_set_char(P, V) (*(u_char *)(P) |= (V))
40 * atomic_clear_char(P, V) (*(u_char *)(P) &= ~(V))
41 * atomic_add_char(P, V) (*(u_char *)(P) += (V))
42 * atomic_subtract_char(P, V) (*(u_char *)(P) -= (V))
43 *
44 * atomic_set_short(P, V) (*(u_short *)(P) |= (V))
45 * atomic_clear_short(P, V) (*(u_short *)(P) &= ~(V))
46 * atomic_add_short(P, V) (*(u_short *)(P) += (V))
47 * atomic_subtract_short(P, V) (*(u_short *)(P) -= (V))
48 *
49 * atomic_set_int(P, V) (*(u_int *)(P) |= (V))
50 * atomic_clear_int(P, V) (*(u_int *)(P) &= ~(V))
51 * atomic_add_int(P, V) (*(u_int *)(P) += (V))
52 * atomic_subtract_int(P, V) (*(u_int *)(P) -= (V))
53 * atomic_readandclear_int(P) (return (*(u_int *)(P)); *(u_int *)(P) = 0;)
54 *
55 * atomic_set_long(P, V) (*(u_long *)(P) |= (V))
56 * atomic_clear_long(P, V) (*(u_long *)(P) &= ~(V))
57 * atomic_add_long(P, V) (*(u_long *)(P) += (V))
58 * atomic_subtract_long(P, V) (*(u_long *)(P) -= (V))
59 * atomic_readandclear_long(P) (return (*(u_long *)(P)); *(u_long *)(P) = 0;)
60 */
61
62 /*
63 * The above functions are expanded inline in the statically-linked
64 * kernel. Lock prefixes are generated if an SMP kernel is being
65 * built.
66 *
67 * Kernel modules call real functions which are built into the kernel.
68 * This allows kernel modules to be portable between UP and SMP systems.
69 */
70 #if defined(KLD_MODULE) || !defined(__GNUCLIKE_ASM)
71 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
72 void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
73
74 int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
75 int atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src);
76 u_int atomic_fetchadd_int(volatile u_int *p, u_int v);
77 u_long atomic_fetchadd_long(volatile u_long *p, u_long v);
78
79 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
80 u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \
81 void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
82
83 #else /* !KLD_MODULE && __GNUCLIKE_ASM */
84
85 /*
86 * For userland, always use lock prefixes so that the binaries will run
87 * on both SMP and !SMP systems.
88 */
89 #if defined(SMP) || !defined(_KERNEL)
90 #define MPLOCKED "lock ; "
91 #else
92 #define MPLOCKED
93 #endif
94
95 /*
96 * The assembly is volatilized to demark potential before-and-after side
97 * effects if an interrupt or SMP collision were to occur.
98 */
99 #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
100 static __inline void \
101 atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
102 { \
103 __asm __volatile(MPLOCKED OP \
104 : "=m" (*p) \
105 : CONS (V), "m" (*p)); \
106 } \
107 struct __hack
108
109 /*
110 * Atomic compare and set, used by the mutex functions
111 *
112 * if (*dst == exp) *dst = src (all 32 bit words)
113 *
114 * Returns 0 on failure, non-zero on success
115 */
116
117 static __inline int
118 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
119 {
120 u_char res;
121
122 __asm __volatile(
123 " " MPLOCKED " "
124 " cmpxchgl %2,%1 ; "
125 " sete %0 ; "
126 "1: "
127 "# atomic_cmpset_int"
128 : "=a" (res), /* 0 */
129 "=m" (*dst) /* 1 */
130 : "r" (src), /* 2 */
131 "a" (exp), /* 3 */
132 "m" (*dst) /* 4 */
133 : "memory");
134
135 return (res);
136 }
137
138 static __inline int
139 atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src)
140 {
141 u_char res;
142
143 __asm __volatile(
144 " " MPLOCKED " "
145 " cmpxchgq %2,%1 ; "
146 " sete %0 ; "
147 "1: "
148 "# atomic_cmpset_long"
149 : "=a" (res), /* 0 */
150 "=m" (*dst) /* 1 */
151 : "r" (src), /* 2 */
152 "a" (exp), /* 3 */
153 "m" (*dst) /* 4 */
154 : "memory");
155
156 return (res);
157 }
158
159 /*
160 * Atomically add the value of v to the integer pointed to by p and return
161 * the previous value of *p.
162 */
163 static __inline u_int
164 atomic_fetchadd_int(volatile u_int *p, u_int v)
165 {
166
167 __asm __volatile(
168 " " MPLOCKED " "
169 " xaddl %0, %1 ; "
170 "# atomic_fetchadd_int"
171 : "+r" (v), /* 0 (result) */
172 "=m" (*p) /* 1 */
173 : "m" (*p)); /* 2 */
174
175 return (v);
176 }
177
178 /*
179 * Atomically add the value of v to the long integer pointed to by p and return
180 * the previous value of *p.
181 */
182 static __inline u_long
183 atomic_fetchadd_long(volatile u_long *p, u_long v)
184 {
185
186 __asm __volatile(
187 " " MPLOCKED " "
188 " xaddq %0, %1 ; "
189 "# atomic_fetchadd_long"
190 : "+r" (v), /* 0 (result) */
191 "=m" (*p) /* 1 */
192 : "m" (*p)); /* 2 */
193
194 return (v);
195 }
196
197 #if defined(_KERNEL) && !defined(SMP)
198
199 /*
200 * We assume that a = b will do atomic loads and stores. However, on a
201 * PentiumPro or higher, reads may pass writes, so for that case we have
202 * to use a serializing instruction (i.e. with LOCK) to do the load in
203 * SMP kernels. For UP kernels, however, the cache of the single processor
204 * is always consistent, so we don't need any memory barriers.
205 */
206 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
207 static __inline u_##TYPE \
208 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
209 { \
210 return (*p); \
211 } \
212 \
213 static __inline void \
214 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
215 { \
216 *p = v; \
217 } \
218 struct __hack
219
220 #else /* !(_KERNEL && !SMP) */
221
222 #define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
223 static __inline u_##TYPE \
224 atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
225 { \
226 u_##TYPE res; \
227 \
228 __asm __volatile(MPLOCKED LOP \
229 : "=a" (res), /* 0 */ \
230 "=m" (*p) /* 1 */ \
231 : "m" (*p) /* 2 */ \
232 : "memory"); \
233 \
234 return (res); \
235 } \
236 \
237 /* \
238 * The XCHG instruction asserts LOCK automagically. \
239 */ \
240 static __inline void \
241 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
242 { \
243 __asm __volatile(SOP \
244 : "=m" (*p), /* 0 */ \
245 "+r" (v) /* 1 */ \
246 : "m" (*p)); /* 2 */ \
247 } \
248 struct __hack
249
250 #endif /* _KERNEL && !SMP */
251
252 #endif /* KLD_MODULE || !__GNUCLIKE_ASM */
253
254 ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v);
255 ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v);
256 ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v);
257 ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v);
258
259 ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v);
260 ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v);
261 ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v);
262 ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v);
263
264 ATOMIC_ASM(set, int, "orl %1,%0", "ir", v);
265 ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v);
266 ATOMIC_ASM(add, int, "addl %1,%0", "ir", v);
267 ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v);
268
269 ATOMIC_ASM(set, long, "orq %1,%0", "ir", v);
270 ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v);
271 ATOMIC_ASM(add, long, "addq %1,%0", "ir", v);
272 ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v);
273
274 ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0");
275 ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0");
276 ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0");
277 ATOMIC_STORE_LOAD(long, "cmpxchgq %0,%1", "xchgq %1,%0");
278
279 #undef ATOMIC_ASM
280 #undef ATOMIC_STORE_LOAD
281
282 #ifndef WANT_FUNCTIONS
283
284 /* Read the current value and store a zero in the destination. */
285 #ifdef __GNUCLIKE_ASM
286
287 static __inline u_int
288 atomic_readandclear_int(volatile u_int *addr)
289 {
290 u_int res;
291
292 res = 0;
293 __asm __volatile(
294 " xchgl %1,%0 ; "
295 "# atomic_readandclear_int"
296 : "+r" (res), /* 0 */
297 "=m" (*addr) /* 1 */
298 : "m" (*addr));
299
300 return (res);
301 }
302
303 static __inline u_long
304 atomic_readandclear_long(volatile u_long *addr)
305 {
306 u_long res;
307
308 res = 0;
309 __asm __volatile(
310 " xchgq %1,%0 ; "
311 "# atomic_readandclear_long"
312 : "+r" (res), /* 0 */
313 "=m" (*addr) /* 1 */
314 : "m" (*addr));
315
316 return (res);
317 }
318
319 #else /* !__GNUCLIKE_ASM */
320
321 u_int atomic_readandclear_int(volatile u_int *addr);
322 u_long atomic_readandclear_long(volatile u_long *addr);
323
324 #endif /* __GNUCLIKE_ASM */
325
326 /* Acquire and release variants are identical to the normal ones. */
327 #define atomic_set_acq_char atomic_set_char
328 #define atomic_set_rel_char atomic_set_char
329 #define atomic_clear_acq_char atomic_clear_char
330 #define atomic_clear_rel_char atomic_clear_char
331 #define atomic_add_acq_char atomic_add_char
332 #define atomic_add_rel_char atomic_add_char
333 #define atomic_subtract_acq_char atomic_subtract_char
334 #define atomic_subtract_rel_char atomic_subtract_char
335
336 #define atomic_set_acq_short atomic_set_short
337 #define atomic_set_rel_short atomic_set_short
338 #define atomic_clear_acq_short atomic_clear_short
339 #define atomic_clear_rel_short atomic_clear_short
340 #define atomic_add_acq_short atomic_add_short
341 #define atomic_add_rel_short atomic_add_short
342 #define atomic_subtract_acq_short atomic_subtract_short
343 #define atomic_subtract_rel_short atomic_subtract_short
344
345 #define atomic_set_acq_int atomic_set_int
346 #define atomic_set_rel_int atomic_set_int
347 #define atomic_clear_acq_int atomic_clear_int
348 #define atomic_clear_rel_int atomic_clear_int
349 #define atomic_add_acq_int atomic_add_int
350 #define atomic_add_rel_int atomic_add_int
351 #define atomic_subtract_acq_int atomic_subtract_int
352 #define atomic_subtract_rel_int atomic_subtract_int
353 #define atomic_cmpset_acq_int atomic_cmpset_int
354 #define atomic_cmpset_rel_int atomic_cmpset_int
355
356 #define atomic_set_acq_long atomic_set_long
357 #define atomic_set_rel_long atomic_set_long
358 #define atomic_clear_acq_long atomic_clear_long
359 #define atomic_clear_rel_long atomic_clear_long
360 #define atomic_add_acq_long atomic_add_long
361 #define atomic_add_rel_long atomic_add_long
362 #define atomic_subtract_acq_long atomic_subtract_long
363 #define atomic_subtract_rel_long atomic_subtract_long
364 #define atomic_cmpset_acq_long atomic_cmpset_long
365 #define atomic_cmpset_rel_long atomic_cmpset_long
366
367 /* Operations on 8-bit bytes. */
368 #define atomic_set_8 atomic_set_char
369 #define atomic_set_acq_8 atomic_set_acq_char
370 #define atomic_set_rel_8 atomic_set_rel_char
371 #define atomic_clear_8 atomic_clear_char
372 #define atomic_clear_acq_8 atomic_clear_acq_char
373 #define atomic_clear_rel_8 atomic_clear_rel_char
374 #define atomic_add_8 atomic_add_char
375 #define atomic_add_acq_8 atomic_add_acq_char
376 #define atomic_add_rel_8 atomic_add_rel_char
377 #define atomic_subtract_8 atomic_subtract_char
378 #define atomic_subtract_acq_8 atomic_subtract_acq_char
379 #define atomic_subtract_rel_8 atomic_subtract_rel_char
380 #define atomic_load_acq_8 atomic_load_acq_char
381 #define atomic_store_rel_8 atomic_store_rel_char
382
383 /* Operations on 16-bit words. */
384 #define atomic_set_16 atomic_set_short
385 #define atomic_set_acq_16 atomic_set_acq_short
386 #define atomic_set_rel_16 atomic_set_rel_short
387 #define atomic_clear_16 atomic_clear_short
388 #define atomic_clear_acq_16 atomic_clear_acq_short
389 #define atomic_clear_rel_16 atomic_clear_rel_short
390 #define atomic_add_16 atomic_add_short
391 #define atomic_add_acq_16 atomic_add_acq_short
392 #define atomic_add_rel_16 atomic_add_rel_short
393 #define atomic_subtract_16 atomic_subtract_short
394 #define atomic_subtract_acq_16 atomic_subtract_acq_short
395 #define atomic_subtract_rel_16 atomic_subtract_rel_short
396 #define atomic_load_acq_16 atomic_load_acq_short
397 #define atomic_store_rel_16 atomic_store_rel_short
398
399 /* Operations on 32-bit double words. */
400 #define atomic_set_32 atomic_set_int
401 #define atomic_set_acq_32 atomic_set_acq_int
402 #define atomic_set_rel_32 atomic_set_rel_int
403 #define atomic_clear_32 atomic_clear_int
404 #define atomic_clear_acq_32 atomic_clear_acq_int
405 #define atomic_clear_rel_32 atomic_clear_rel_int
406 #define atomic_add_32 atomic_add_int
407 #define atomic_add_acq_32 atomic_add_acq_int
408 #define atomic_add_rel_32 atomic_add_rel_int
409 #define atomic_subtract_32 atomic_subtract_int
410 #define atomic_subtract_acq_32 atomic_subtract_acq_int
411 #define atomic_subtract_rel_32 atomic_subtract_rel_int
412 #define atomic_load_acq_32 atomic_load_acq_int
413 #define atomic_store_rel_32 atomic_store_rel_int
414 #define atomic_cmpset_32 atomic_cmpset_int
415 #define atomic_cmpset_acq_32 atomic_cmpset_acq_int
416 #define atomic_cmpset_rel_32 atomic_cmpset_rel_int
417 #define atomic_readandclear_32 atomic_readandclear_int
418 #define atomic_fetchadd_32 atomic_fetchadd_int
419
420 /* Operations on 64-bit quad words. */
421 #define atomic_set_64 atomic_set_long
422 #define atomic_set_acq_64 atomic_set_acq_long
423 #define atomic_set_rel_64 atomic_set_rel_long
424 #define atomic_clear_64 atomic_clear_long
425 #define atomic_clear_acq_64 atomic_clear_acq_long
426 #define atomic_clear_rel_64 atomic_clear_rel_long
427 #define atomic_add_64 atomic_add_long
428 #define atomic_add_acq_64 atomic_add_acq_long
429 #define atomic_add_rel_64 atomic_add_rel_long
430 #define atomic_subtract_64 atomic_subtract_long
431 #define atomic_subtract_acq_64 atomic_subtract_acq_long
432 #define atomic_subtract_rel_64 atomic_subtract_rel_long
433 #define atomic_load_acq_64 atomic_load_acq_long
434 #define atomic_store_rel_64 atomic_store_rel_long
435 #define atomic_cmpset_64 atomic_cmpset_long
436 #define atomic_cmpset_acq_64 atomic_cmpset_acq_long
437 #define atomic_cmpset_rel_64 atomic_cmpset_rel_long
438 #define atomic_readandclear_64 atomic_readandclear_long
439
440 /* Operations on pointers. */
441 #define atomic_set_ptr atomic_set_long
442 #define atomic_set_acq_ptr atomic_set_acq_long
443 #define atomic_set_rel_ptr atomic_set_rel_long
444 #define atomic_clear_ptr atomic_clear_long
445 #define atomic_clear_acq_ptr atomic_clear_acq_long
446 #define atomic_clear_rel_ptr atomic_clear_rel_long
447 #define atomic_add_ptr atomic_add_long
448 #define atomic_add_acq_ptr atomic_add_acq_long
449 #define atomic_add_rel_ptr atomic_add_rel_long
450 #define atomic_subtract_ptr atomic_subtract_long
451 #define atomic_subtract_acq_ptr atomic_subtract_acq_long
452 #define atomic_subtract_rel_ptr atomic_subtract_rel_long
453 #define atomic_load_acq_ptr atomic_load_acq_long
454 #define atomic_store_rel_ptr atomic_store_rel_long
455 #define atomic_cmpset_ptr atomic_cmpset_long
456 #define atomic_cmpset_acq_ptr atomic_cmpset_acq_long
457 #define atomic_cmpset_rel_ptr atomic_cmpset_rel_long
458 #define atomic_readandclear_ptr atomic_readandclear_long
459
460 #endif /* !WANT_FUNCTIONS */
461
462 #endif /* !_MACHINE_ATOMIC_H_ */
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