1 /* Atomic operations. Pure ARM version.
2 Copyright (C) 2002-2023 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 #define __HAVE_64B_ATOMICS 0
20 #define USE_ATOMIC_COMPILER_BUILTINS 1
21 #define ATOMIC_EXCHANGE_USES_CAS 1
22
23 void __arm_link_error (void);
24
25 #ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
26 # define atomic_full_barrier() __sync_synchronize ()
27 #else
28 # define atomic_full_barrier() __arm_assisted_full_barrier ()
29 #endif
30
31 /* An OS-specific atomic-machine.h file will define this macro if
32 the OS can provide something. If not, we'll fail to build
33 with a compiler that doesn't supply the operation. */
34 #ifndef __arm_assisted_full_barrier
35 # define __arm_assisted_full_barrier() __arm_link_error()
36 #endif
37
38 /* Use the atomic builtins provided by GCC in case the backend provides
39 a pattern to do this efficiently. */
40 #ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
41
42 # define atomic_exchange_acq(mem, value) \
43 __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_ACQUIRE)
44
45 # define atomic_exchange_rel(mem, value) \
46 __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_RELEASE)
47
48 /* Atomic exchange (without compare). */
49
50 # define __arch_exchange_8_int(mem, newval, model) \
51 (__arm_link_error (), (typeof (*mem)) 0)
52
53 # define __arch_exchange_16_int(mem, newval, model) \
54 (__arm_link_error (), (typeof (*mem)) 0)
55
56 # define __arch_exchange_32_int(mem, newval, model) \
57 __atomic_exchange_n (mem, newval, model)
58
59 # define __arch_exchange_64_int(mem, newval, model) \
60 (__arm_link_error (), (typeof (*mem)) 0)
61
62 /* Compare and exchange with "acquire" semantics, ie barrier after. */
63
64 # define atomic_compare_and_exchange_bool_acq(mem, new, old) \
65 __atomic_bool_bysize (__arch_compare_and_exchange_bool, int, \
66 mem, new, old, __ATOMIC_ACQUIRE)
67
68 # define atomic_compare_and_exchange_val_acq(mem, new, old) \
69 __atomic_val_bysize (__arch_compare_and_exchange_val, int, \
70 mem, new, old, __ATOMIC_ACQUIRE)
71
72 /* Compare and exchange with "release" semantics, ie barrier before. */
73
74 # define atomic_compare_and_exchange_val_rel(mem, new, old) \
75 __atomic_val_bysize (__arch_compare_and_exchange_val, int, \
76 mem, new, old, __ATOMIC_RELEASE)
77
78 /* Compare and exchange.
79 For all "bool" routines, we return FALSE if exchange successful. */
80
81 # define __arch_compare_and_exchange_bool_8_int(mem, newval, oldval, model) \
82 ({__arm_link_error (); 0; })
83
84 # define __arch_compare_and_exchange_bool_16_int(mem, newval, oldval, model) \
85 ({__arm_link_error (); 0; })
86
87 # define __arch_compare_and_exchange_bool_32_int(mem, newval, oldval, model) \
88 ({ \
89 typeof (*mem) __oldval = (oldval); \
90 !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
91 model, __ATOMIC_RELAXED); \
92 })
93
94 # define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
95 ({__arm_link_error (); 0; })
96
97 # define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model) \
98 ({__arm_link_error (); oldval; })
99
100 # define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model) \
101 ({__arm_link_error (); oldval; })
102
103 # define __arch_compare_and_exchange_val_32_int(mem, newval, oldval, model) \
104 ({ \
105 typeof (*mem) __oldval = (oldval); \
106 __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
107 model, __ATOMIC_RELAXED); \
108 __oldval; \
109 })
110
111 # define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \
112 ({__arm_link_error (); oldval; })
113
114 #else
115 # define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
116 __arm_assisted_compare_and_exchange_val_32_acq ((mem), (newval), (oldval))
117 #endif
118
119 #ifndef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
120 /* We don't support atomic operations on any non-word types.
121 So make them link errors. */
122 # define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \
123 ({ __arm_link_error (); oldval; })
124
125 # define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
126 ({ __arm_link_error (); oldval; })
127
128 # define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
129 ({ __arm_link_error (); oldval; })
130 #endif
131
132 /* An OS-specific atomic-machine.h file will define this macro if
133 the OS can provide something. If not, we'll fail to build
134 with a compiler that doesn't supply the operation. */
135 #ifndef __arm_assisted_compare_and_exchange_val_32_acq
136 # define __arm_assisted_compare_and_exchange_val_32_acq(mem, newval, oldval) \
137 ({ __arm_link_error (); oldval; })
138 #endif