1 /* Low-level functions for atomic operations. RISC-V version.
2 Copyright (C) 2014-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #ifndef _LINUX_RISCV_BITS_ATOMIC_H
20 #define _LINUX_RISCV_BITS_ATOMIC_H 1
21
22 #define atomic_full_barrier() __sync_synchronize ()
23
24 #ifdef __riscv_atomic
25
26 # define __HAVE_64B_ATOMICS (__riscv_xlen >= 64)
27 # define USE_ATOMIC_COMPILER_BUILTINS 1
28 # define ATOMIC_EXCHANGE_USES_CAS 0
29
30 /* Compare and exchange.
31 For all "bool" routines, we return FALSE if exchange successful. */
32
33 # define __arch_compare_and_exchange_bool_8_int(mem, newval, oldval, model) \
34 ({ \
35 typeof (*mem) __oldval = (oldval); \
36 !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
37 model, __ATOMIC_RELAXED); \
38 })
39
40 # define __arch_compare_and_exchange_bool_16_int(mem, newval, oldval, model) \
41 ({ \
42 typeof (*mem) __oldval = (oldval); \
43 !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
44 model, __ATOMIC_RELAXED); \
45 })
46
47 # define __arch_compare_and_exchange_bool_32_int(mem, newval, oldval, model) \
48 ({ \
49 typeof (*mem) __oldval = (oldval); \
50 !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
51 model, __ATOMIC_RELAXED); \
52 })
53
54 # define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
55 ({ \
56 typeof (*mem) __oldval = (oldval); \
57 !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
58 model, __ATOMIC_RELAXED); \
59 })
60
61 # define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model) \
62 ({ \
63 typeof (*mem) __oldval = (oldval); \
64 __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
65 model, __ATOMIC_RELAXED); \
66 __oldval; \
67 })
68
69 # define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model) \
70 ({ \
71 typeof (*mem) __oldval = (oldval); \
72 __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
73 model, __ATOMIC_RELAXED); \
74 __oldval; \
75 })
76
77 # define __arch_compare_and_exchange_val_32_int(mem, newval, oldval, model) \
78 ({ \
79 typeof (*mem) __oldval = (oldval); \
80 __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
81 model, __ATOMIC_RELAXED); \
82 __oldval; \
83 })
84
85 # define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \
86 ({ \
87 typeof (*mem) __oldval = (oldval); \
88 __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
89 model, __ATOMIC_RELAXED); \
90 __oldval; \
91 })
92
93 /* Atomic compare and exchange. */
94
95 # define atomic_compare_and_exchange_bool_acq(mem, new, old) \
96 __atomic_bool_bysize (__arch_compare_and_exchange_bool, int, \
97 mem, new, old, __ATOMIC_ACQUIRE)
98
99 # define atomic_compare_and_exchange_val_acq(mem, new, old) \
100 __atomic_val_bysize (__arch_compare_and_exchange_val, int, \
101 mem, new, old, __ATOMIC_ACQUIRE)
102
103 # define atomic_compare_and_exchange_val_rel(mem, new, old) \
104 __atomic_val_bysize (__arch_compare_and_exchange_val, int, \
105 mem, new, old, __ATOMIC_RELEASE)
106
107 /* Atomic exchange (without compare). */
108
109 # define __arch_exchange_8_int(mem, newval, model) \
110 __atomic_exchange_n (mem, newval, model)
111
112 # define __arch_exchange_16_int(mem, newval, model) \
113 __atomic_exchange_n (mem, newval, model)
114
115 # define __arch_exchange_32_int(mem, newval, model) \
116 __atomic_exchange_n (mem, newval, model)
117
118 # define __arch_exchange_64_int(mem, newval, model) \
119 __atomic_exchange_n (mem, newval, model)
120
121 # define atomic_exchange_acq(mem, value) \
122 __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_ACQUIRE)
123
124 # define atomic_exchange_rel(mem, value) \
125 __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_RELEASE)
126
127 /* Atomically add value and return the previous (unincremented) value. */
128
129 # define __arch_exchange_and_add_8_int(mem, value, model) \
130 __atomic_fetch_add (mem, value, model)
131
132 # define __arch_exchange_and_add_16_int(mem, value, model) \
133 __atomic_fetch_add (mem, value, model)
134
135 # define __arch_exchange_and_add_32_int(mem, value, model) \
136 __atomic_fetch_add (mem, value, model)
137
138 # define __arch_exchange_and_add_64_int(mem, value, model) \
139 __atomic_fetch_add (mem, value, model)
140
141 # define atomic_exchange_and_add_acq(mem, value) \
142 __atomic_val_bysize (__arch_exchange_and_add, int, mem, value, \
143 __ATOMIC_ACQUIRE)
144
145 # define atomic_exchange_and_add_rel(mem, value) \
146 __atomic_val_bysize (__arch_exchange_and_add, int, mem, value, \
147 __ATOMIC_RELEASE)
148
149 /* Miscellaneous. */
150
151 # define asm_amo(which, ordering, mem, value) ({ \
152 __atomic_check_size (mem); \
153 typeof (*mem) __tmp; \
154 if (sizeof (__tmp) == 4) \
155 asm volatile (which ".w" ordering "\t%0, %z2, %1" \
156 : "=r" (__tmp), "+A" (* (mem)) \
157 : "rJ" (value)); \
158 else if (sizeof (__tmp) == 8) \
159 asm volatile (which ".d" ordering "\t%0, %z2, %1" \
160 : "=r" (__tmp), "+A" (* (mem)) \
161 : "rJ" (value)); \
162 else \
163 abort (); \
164 __tmp; })
165
166 # define atomic_max(mem, value) asm_amo ("amomaxu", ".aq", mem, value)
167 # define atomic_min(mem, value) asm_amo ("amominu", ".aq", mem, value)
168
169 # define atomic_bit_test_set(mem, bit) \
170 ({ typeof (*mem) __mask = (typeof (*mem))1 << (bit); \
171 asm_amo ("amoor", ".aq", mem, __mask) & __mask; })
172
173 # define catomic_exchange_and_add(mem, value) \
174 atomic_exchange_and_add (mem, value)
175 # define catomic_max(mem, value) atomic_max (mem, value)
176
177 #else /* __riscv_atomic */
178 # error "ISAs that do not subsume the A extension are not supported"
179 #endif /* !__riscv_atomic */
180
181 #endif /* bits/atomic.h */