atomic.h revision 361181 
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2018 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice unmodified, this list of conditions, and the following
13 *    disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: stable/11/sys/compat/linuxkpi/common/include/asm/atomic.h 361181 2020-05-18 09:12:13Z hselasky $
30 */
31
32#ifndef _ASM_ATOMIC_H_
33#define	_ASM_ATOMIC_H_
34
35#include <linux/compiler.h>
36#include <sys/types.h>
37#include <machine/atomic.h>
38
39#define	ATOMIC_INIT(x)	{ .counter = (x) }
40
41typedef struct {
42	volatile int counter;
43} atomic_t;
44
45/*------------------------------------------------------------------------*
46 *	32-bit atomic operations
47 *------------------------------------------------------------------------*/
48
49#define	atomic_add(i, v)		atomic_add_return((i), (v))
50#define	atomic_sub(i, v)		atomic_sub_return((i), (v))
51#define	atomic_inc_return(v)		atomic_add_return(1, (v))
52#define	atomic_add_negative(i, v)	(atomic_add_return((i), (v)) < 0)
53#define	atomic_add_and_test(i, v)	(atomic_add_return((i), (v)) == 0)
54#define	atomic_sub_and_test(i, v)	(atomic_sub_return((i), (v)) == 0)
55#define	atomic_dec_and_test(v)		(atomic_sub_return(1, (v)) == 0)
56#define	atomic_inc_and_test(v)		(atomic_add_return(1, (v)) == 0)
57#define	atomic_dec_return(v)		atomic_sub_return(1, (v))
58#define	atomic_inc_not_zero(v)		atomic_add_unless((v), 1, 0)
59
60static inline int
61atomic_add_return(int i, atomic_t *v)
62{
63	return i + atomic_fetchadd_int(&v->counter, i);
64}
65
66static inline int
67atomic_sub_return(int i, atomic_t *v)
68{
69	return atomic_fetchadd_int(&v->counter, -i) - i;
70}
71
72static inline void
73atomic_set(atomic_t *v, int i)
74{
75	WRITE_ONCE(v->counter, i);
76}
77
78static inline void
79atomic_set_release(atomic_t *v, int i)
80{
81	atomic_store_rel_int(&v->counter, i);
82}
83
84static inline void
85atomic_set_mask(unsigned int mask, atomic_t *v)
86{
87	atomic_set_int(&v->counter, mask);
88}
89
90static inline int
91atomic_read(const atomic_t *v)
92{
93	return READ_ONCE(v->counter);
94}
95
96static inline int
97atomic_inc(atomic_t *v)
98{
99	return atomic_fetchadd_int(&v->counter, 1) + 1;
100}
101
102static inline int
103atomic_dec(atomic_t *v)
104{
105	return atomic_fetchadd_int(&v->counter, -1) - 1;
106}
107
108static inline int
109atomic_add_unless(atomic_t *v, int a, int u)
110{
111	int c = atomic_read(v);
112
113	for (;;) {
114		if (unlikely(c == u))
115			break;
116		if (likely(atomic_fcmpset_int(&v->counter, &c, c + a)))
117			break;
118	}
119	return (c != u);
120}
121
122static inline int
123atomic_fetch_add_unless(atomic_t *v, int a, int u)
124{
125	int c = atomic_read(v);
126
127	for (;;) {
128		if (unlikely(c == u))
129			break;
130		if (likely(atomic_fcmpset_int(&v->counter, &c, c + a)))
131			break;
132	}
133	return (c);
134}
135
136static inline void
137atomic_clear_mask(unsigned int mask, atomic_t *v)
138{
139	atomic_clear_int(&v->counter, mask);
140}
141
142static inline int
143atomic_xchg(atomic_t *v, int i)
144{
145#if defined(__i386__) || defined(__amd64__) || \
146    defined(__arm__) || defined(__aarch64__) || \
147    defined(__powerpc__)
148	return (atomic_swap_int(&v->counter, i));
149#else
150	int ret = atomic_read(v);
151
152	while (!atomic_fcmpset_int(&v->counter, &ret, i))
153		;
154	return (ret);
155#endif
156}
157
158static inline int
159atomic_cmpxchg(atomic_t *v, int old, int new)
160{
161	int ret = old;
162
163	for (;;) {
164		if (atomic_fcmpset_int(&v->counter, &ret, new))
165			break;
166		if (ret != old)
167			break;
168	}
169	return (ret);
170}
171
172#if defined(__i386__) || defined(__amd64__)
173#define	LINUXKPI_ATOMIC_8(...) __VA_ARGS__
174#define	LINUXKPI_ATOMIC_16(...) __VA_ARGS__
175#else
176#define	LINUXKPI_ATOMIC_8(...)
177#define	LINUXKPI_ATOMIC_16(...)
178#endif
179
180#if defined(__amd64__) || (defined(__ARM_ARCH) && (__ARM_ARCH >= 6)) ||	\
181    defined(__aarch64__) || defined(__powerpc64__) || defined(__riscv)
182#define	LINUXKPI_ATOMIC_64(...) __VA_ARGS__
183#else
184#define	LINUXKPI_ATOMIC_64(...)
185#endif
186
187#define	cmpxchg(ptr, old, new) ({					\
188	union {								\
189		__typeof(*(ptr)) val;					\
190		u8 u8[0];						\
191		u16 u16[0];						\
192		u32 u32[0];						\
193		u64 u64[0];						\
194	} __ret = { .val = (old) }, __new = { .val = (new) };		\
195									\
196	CTASSERT(							\
197	    LINUXKPI_ATOMIC_8(sizeof(__ret.val) == 1 ||)		\
198	    LINUXKPI_ATOMIC_16(sizeof(__ret.val) == 2 ||)		\
199	    LINUXKPI_ATOMIC_64(sizeof(__ret.val) == 8 ||)		\
200	    sizeof(__ret.val) == 4);					\
201									\
202	switch (sizeof(__ret.val)) {					\
203	LINUXKPI_ATOMIC_8(						\
204	case 1:								\
205		while (!atomic_fcmpset_8((volatile u8 *)(ptr),		\
206		    __ret.u8, __new.u8[0]) && __ret.val == (old))	\
207			;						\
208		break;							\
209	)								\
210	LINUXKPI_ATOMIC_16(						\
211	case 2:								\
212		while (!atomic_fcmpset_16((volatile u16 *)(ptr),	\
213		    __ret.u16, __new.u16[0]) && __ret.val == (old))	\
214			;						\
215		break;							\
216	)								\
217	case 4:								\
218		while (!atomic_fcmpset_32((volatile u32 *)(ptr),	\
219		    __ret.u32, __new.u32[0]) && __ret.val == (old))	\
220			;						\
221		break;							\
222	LINUXKPI_ATOMIC_64(						\
223	case 8:								\
224		while (!atomic_fcmpset_64((volatile u64 *)(ptr),	\
225		    __ret.u64, __new.u64[0]) && __ret.val == (old))	\
226			;						\
227		break;							\
228	)								\
229	}								\
230	__ret.val;							\
231})
232
233#define	cmpxchg_relaxed(...)	cmpxchg(__VA_ARGS__)
234
235#define	xchg(ptr, new) ({						\
236	union {								\
237		__typeof(*(ptr)) val;					\
238		u8 u8[0];						\
239		u16 u16[0];						\
240		u32 u32[0];						\
241		u64 u64[0];						\
242	} __ret, __new = { .val = (new) };				\
243									\
244	CTASSERT(							\
245	    LINUXKPI_ATOMIC_8(sizeof(__ret.val) == 1 ||)		\
246	    LINUXKPI_ATOMIC_16(sizeof(__ret.val) == 2 ||)		\
247	    LINUXKPI_ATOMIC_64(sizeof(__ret.val) == 8 ||)		\
248	    sizeof(__ret.val) == 4);					\
249									\
250	switch (sizeof(__ret.val)) {					\
251	LINUXKPI_ATOMIC_8(						\
252	case 1:								\
253		__ret.val = READ_ONCE(*ptr);				\
254		while (!atomic_fcmpset_8((volatile u8 *)(ptr),		\
255	            __ret.u8, __new.u8[0]))				\
256			;						\
257		break;							\
258	)								\
259	LINUXKPI_ATOMIC_16(						\
260	case 2:								\
261		__ret.val = READ_ONCE(*ptr);				\
262		while (!atomic_fcmpset_16((volatile u16 *)(ptr),	\
263	            __ret.u16, __new.u16[0]))				\
264			;						\
265		break;							\
266	)								\
267	case 4:								\
268		__ret.u32[0] = atomic_swap_32((volatile u32 *)(ptr),	\
269		    __new.u32[0]);					\
270		break;							\
271	LINUXKPI_ATOMIC_64(						\
272	case 8:								\
273		__ret.u64[0] = atomic_swap_64((volatile u64 *)(ptr),	\
274		    __new.u64[0]);					\
275		break;							\
276	)								\
277	}								\
278	__ret.val;							\
279})
280
281static inline int
282atomic_dec_if_positive(atomic_t *v)
283{
284	int retval;
285	int old;
286
287	old = atomic_read(v);
288	for (;;) {
289		retval = old - 1;
290		if (unlikely(retval < 0))
291			break;
292		if (likely(atomic_fcmpset_int(&v->counter, &old, retval)))
293			break;
294	}
295	return (retval);
296}
297
298#define	LINUX_ATOMIC_OP(op, c_op)				\
299static inline void atomic_##op(int i, atomic_t *v)		\
300{								\
301	int c, old;						\
302								\
303	c = v->counter;						\
304	while ((old = atomic_cmpxchg(v, c, c c_op i)) != c)	\
305		c = old;					\
306}
307
308#define	LINUX_ATOMIC_FETCH_OP(op, c_op)				\
309static inline int atomic_fetch_##op(int i, atomic_t *v)		\
310{								\
311	int c, old;						\
312								\
313	c = v->counter;						\
314	while ((old = atomic_cmpxchg(v, c, c c_op i)) != c)	\
315		c = old;					\
316								\
317	return (c);						\
318}
319
320LINUX_ATOMIC_OP(or, |)
321LINUX_ATOMIC_OP(and, &)
322LINUX_ATOMIC_OP(andnot, &~)
323LINUX_ATOMIC_OP(xor, ^)
324
325LINUX_ATOMIC_FETCH_OP(or, |)
326LINUX_ATOMIC_FETCH_OP(and, &)
327LINUX_ATOMIC_FETCH_OP(andnot, &~)
328LINUX_ATOMIC_FETCH_OP(xor, ^)
329
330#endif					/* _ASM_ATOMIC_H_ */
331