atomic.h revision 337120 
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 337120 2018-08-02 09:03:08Z 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;
112
113	for (;;) {
114		c = atomic_read(v);
115		if (unlikely(c == u))
116			break;
117		if (likely(atomic_cmpset_int(&v->counter, c, c + a)))
118			break;
119	}
120	return (c != u);
121}
122
123static inline void
124atomic_clear_mask(unsigned int mask, atomic_t *v)
125{
126	atomic_clear_int(&v->counter, mask);
127}
128
129static inline int
130atomic_xchg(atomic_t *v, int i)
131{
132#if defined(__i386__) || defined(__amd64__) || \
133    defined(__arm__) || defined(__aarch64__) || \
134    defined(__powerpc__)
135	return (atomic_swap_int(&v->counter, i));
136#else
137	int ret;
138	for (;;) {
139		ret = READ_ONCE(v->counter);
140		if (atomic_cmpset_int(&v->counter, ret, i))
141			break;
142	}
143	return (ret);
144#endif
145}
146
147static inline int
148atomic_cmpxchg(atomic_t *v, int old, int new)
149{
150	int ret = old;
151
152	for (;;) {
153		if (atomic_cmpset_int(&v->counter, old, new))
154			break;
155		ret = READ_ONCE(v->counter);
156		if (ret != old)
157			break;
158	}
159	return (ret);
160}
161
162#if defined(__i386__) || defined(__amd64__)
163#define	LINUXKPI_ATOMIC_8(...) __VA_ARGS__
164#define	LINUXKPI_ATOMIC_16(...) __VA_ARGS__
165#else
166#define	LINUXKPI_ATOMIC_8(...)
167#define	LINUXKPI_ATOMIC_16(...)
168#endif
169
170#if defined(__amd64__) || (defined(__ARM_ARCH) && (__ARM_ARCH >= 6)) ||	\
171    defined(__aarch64__) || defined(__powerpc64__) || defined(__riscv)
172#define	LINUXKPI_ATOMIC_64(...) __VA_ARGS__
173#else
174#define	LINUXKPI_ATOMIC_64(...)
175#endif
176
177#define	cmpxchg(ptr, old, new) ({					\
178	union {								\
179		__typeof(*(ptr)) val;					\
180		u8 u8[0];						\
181		u16 u16[0];						\
182		u32 u32[0];						\
183		u64 u64[0];						\
184	} __ret = { .val = (old) }, __new = { .val = (new) };		\
185									\
186	CTASSERT(							\
187	    LINUXKPI_ATOMIC_8(sizeof(__ret.val) == 1 ||)		\
188	    LINUXKPI_ATOMIC_16(sizeof(__ret.val) == 2 ||)		\
189	    LINUXKPI_ATOMIC_64(sizeof(__ret.val) == 8 ||)		\
190	    sizeof(__ret.val) == 4);					\
191									\
192	switch (sizeof(__ret.val)) {					\
193	LINUXKPI_ATOMIC_8(						\
194	case 1:								\
195		while (!atomic_fcmpset_8((volatile u8 *)(ptr),		\
196		    __ret.u8, __new.u8[0]) && __ret.val == (old))	\
197			;						\
198		break;							\
199	)								\
200	LINUXKPI_ATOMIC_16(						\
201	case 2:								\
202		while (!atomic_fcmpset_16((volatile u16 *)(ptr),	\
203		    __ret.u16, __new.u16[0]) && __ret.val == (old))	\
204			;						\
205		break;							\
206	)								\
207	case 4:								\
208		while (!atomic_fcmpset_32((volatile u32 *)(ptr),	\
209		    __ret.u32, __new.u32[0]) && __ret.val == (old))	\
210			;						\
211		break;							\
212	LINUXKPI_ATOMIC_64(						\
213	case 8:								\
214		while (!atomic_fcmpset_64((volatile u64 *)(ptr),	\
215		    __ret.u64, __new.u64[0]) && __ret.val == (old))	\
216			;						\
217		break;							\
218	)								\
219	}								\
220	__ret.val;							\
221})
222
223#define	cmpxchg_relaxed(...)	cmpxchg(__VA_ARGS__)
224
225#define	xchg(ptr, new) ({						\
226	union {								\
227		__typeof(*(ptr)) val;					\
228		u8 u8[0];						\
229		u16 u16[0];						\
230		u32 u32[0];						\
231		u64 u64[0];						\
232	} __ret, __new = { .val = (new) };				\
233									\
234	CTASSERT(							\
235	    LINUXKPI_ATOMIC_8(sizeof(__ret.val) == 1 ||)		\
236	    LINUXKPI_ATOMIC_16(sizeof(__ret.val) == 2 ||)		\
237	    LINUXKPI_ATOMIC_64(sizeof(__ret.val) == 8 ||)		\
238	    sizeof(__ret.val) == 4);					\
239									\
240	switch (sizeof(__ret.val)) {					\
241	LINUXKPI_ATOMIC_8(						\
242	case 1:								\
243		__ret.val = READ_ONCE(*ptr);				\
244		while (!atomic_fcmpset_8((volatile u8 *)(ptr),		\
245	            __ret.u8, __new.u8[0]))				\
246			;						\
247		break;							\
248	)								\
249	LINUXKPI_ATOMIC_16(						\
250	case 2:								\
251		__ret.val = READ_ONCE(*ptr);				\
252		while (!atomic_fcmpset_16((volatile u16 *)(ptr),	\
253	            __ret.u16, __new.u16[0]))				\
254			;						\
255		break;							\
256	)								\
257	case 4:								\
258		__ret.u32[0] = atomic_swap_32((volatile u32 *)(ptr),	\
259		    __new.u32[0]);					\
260		break;							\
261	LINUXKPI_ATOMIC_64(						\
262	case 8:								\
263		__ret.u64[0] = atomic_swap_64((volatile u64 *)(ptr),	\
264		    __new.u64[0]);					\
265		break;							\
266	)								\
267	}								\
268	__ret.val;							\
269})
270
271static inline int
272atomic_dec_if_positive(atomic_t *v)
273{
274	int retval;
275	int old;
276
277	old = atomic_read(v);
278	for (;;) {
279		retval = old - 1;
280		if (unlikely(retval < 0))
281			break;
282		if (likely(atomic_fcmpset_int(&v->counter, &old, retval)))
283			break;
284	}
285	return (retval);
286}
287
288#define	LINUX_ATOMIC_OP(op, c_op)				\
289static inline void atomic_##op(int i, atomic_t *v)		\
290{								\
291	int c, old;						\
292								\
293	c = v->counter;						\
294	while ((old = atomic_cmpxchg(v, c, c c_op i)) != c)	\
295		c = old;					\
296}
297
298#define	LINUX_ATOMIC_FETCH_OP(op, c_op)				\
299static inline int atomic_fetch_##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	return (c);						\
308}
309
310LINUX_ATOMIC_OP(or, |)
311LINUX_ATOMIC_OP(and, &)
312LINUX_ATOMIC_OP(andnot, &~)
313LINUX_ATOMIC_OP(xor, ^)
314
315LINUX_ATOMIC_FETCH_OP(or, |)
316LINUX_ATOMIC_FETCH_OP(and, &)
317LINUX_ATOMIC_FETCH_OP(andnot, &~)
318LINUX_ATOMIC_FETCH_OP(xor, ^)
319
320#endif					/* _ASM_ATOMIC_H_ */
321