1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2019 Justin Hibbits
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD$
28 */
29
30 #include <sys/cdefs.h>
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/lock.h>
34 #include <sys/mutex.h>
35 #include <sys/smp.h>
36 #include <sys/systm.h>
37
38 #include <machine/atomic.h>
39 #include <machine/param.h>
40
41 #include <vm/vm.h>
42 #include <vm/pmap.h>
43
44 enum {
45 ATOMIC64_ADD,
46 ATOMIC64_CLEAR,
47 ATOMIC64_CMPSET,
48 ATOMIC64_FCMPSET,
49 ATOMIC64_FETCHADD,
50 ATOMIC64_LOAD,
51 ATOMIC64_SET,
52 ATOMIC64_SUBTRACT,
53 ATOMIC64_STORE,
54 ATOMIC64_SWAP
55 };
56
57 #ifdef _KERNEL
58 #ifdef SMP
59
60 #define A64_POOL_SIZE MAXCPU
61 /* Estimated size of a cacheline */
62 #define CACHE_ALIGN CACHE_LINE_SIZE
63 static struct mtx a64_mtx_pool[A64_POOL_SIZE];
64
65 #define GET_MUTEX(p) \
66 (&a64_mtx_pool[(pmap_kextract((vm_offset_t)p) / CACHE_ALIGN) % (A64_POOL_SIZE)])
67
68 #define LOCK_A64() \
69 struct mtx *_amtx = GET_MUTEX(p); \
70 if (smp_started) mtx_lock(_amtx)
71
72 #define UNLOCK_A64() if (smp_started) mtx_unlock(_amtx)
73
74 #else /* !SMP */
75
76 #define LOCK_A64() { register_t s = intr_disable()
77 #define UNLOCK_A64() intr_restore(s); }
78
79 #endif /* SMP */
80
81 #define ATOMIC64_EMU_UN(op, rt, block, ret) \
82 rt \
83 atomic_##op##_64(volatile uint64_t *p) { \
84 uint64_t tmp __unused; \
85 LOCK_A64(); \
86 block; \
87 UNLOCK_A64(); \
88 ret; } struct hack
89
90 #define ATOMIC64_EMU_BIN(op, rt, block, ret) \
91 rt \
92 atomic_##op##_64(volatile uint64_t *p, uint64_t v) { \
93 uint64_t tmp __unused; \
94 LOCK_A64(); \
95 block; \
96 UNLOCK_A64(); \
97 ret; } struct hack
98
99 ATOMIC64_EMU_BIN(add, void, (*p = *p + v), return);
100 ATOMIC64_EMU_BIN(clear, void, *p &= ~v, return);
101 ATOMIC64_EMU_BIN(fetchadd, uint64_t, (*p = *p + v, v = *p - v), return (v));
102 ATOMIC64_EMU_UN(load, uint64_t, (tmp = *p), return (tmp));
103 ATOMIC64_EMU_BIN(set, void, *p |= v, return);
104 ATOMIC64_EMU_BIN(subtract, void, (*p = *p - v), return);
105 ATOMIC64_EMU_BIN(store, void, *p = v, return);
106 ATOMIC64_EMU_BIN(swap, uint64_t, tmp = *p; *p = v; v = tmp, return(v));
107
108 int atomic_cmpset_64(volatile uint64_t *p, uint64_t old, uint64_t new)
109 {
110 uint64_t tmp;
111
112 LOCK_A64();
113 tmp = *p;
114 if (tmp == old)
115 *p = new;
116 UNLOCK_A64();
117
118 return (tmp == old);
119 }
120
121 int atomic_fcmpset_64(volatile uint64_t *p, uint64_t *old, uint64_t new)
122 {
123 uint64_t tmp, tmp_old;
124
125 LOCK_A64();
126 tmp = *p;
127 tmp_old = *old;
128 if (tmp == tmp_old)
129 *p = new;
130 else
131 *old = tmp;
132 UNLOCK_A64();
133
134 return (tmp == tmp_old);
135 }
136
137 #ifdef SMP
138 static void
139 atomic64_mtxinit(void *x __unused)
140 {
141 int i;
142
143 for (i = 0; i < A64_POOL_SIZE; i++)
144 mtx_init(&a64_mtx_pool[i], "atomic64 mutex", NULL, MTX_DEF);
145 }
146
147 SYSINIT(atomic64_mtxinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, atomic64_mtxinit, NULL);
148 #endif /* SMP */
149
150 #endif /* _KERNEL */
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