1 /* Copyright (C) 2003-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 /* Activate all C11 atomic builtins.
19
20 Note:
21 E.g. in nptl/pthread_key_delete.c if compiled with GCCs 6 and before,
22 an extra stack-frame is generated and the old value is stored on stack
23 before cs instruction but it never loads this value from stack.
24 An unreleased GCC 7 omit those stack operations.
25
26 E.g. in nptl/pthread_once.c the condition code of cs instruction is
27 evaluated by a sequence of ipm, sra, compare and jump instructions instead
28 of one conditional jump instruction. This also occurs with an unreleased
29 GCC 7.
30
31 The atomic_fetch_abc_def C11 builtins are now using load-and-abc instructions
32 on z196 zarch and higher cpus instead of a loop with compare-and-swap
33 instruction. */
34 #define USE_ATOMIC_COMPILER_BUILTINS 1
35
36 #ifdef __s390x__
37 # define __HAVE_64B_ATOMICS 1
38 #else
39 # define __HAVE_64B_ATOMICS 0
40 #endif
41
42 #define ATOMIC_EXCHANGE_USES_CAS 1
43
44 /* Implement some of the non-C11 atomic macros from include/atomic.h
45 with help of the C11 atomic builtins. The other non-C11 atomic macros
46 are using the macros defined here. */
47
48 /* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
49 Return the old *MEM value. */
50 #define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
51 ({ __atomic_check_size((mem)); \
52 typeof ((__typeof (*(mem))) *(mem)) __atg1_oldval = (oldval); \
53 __atomic_compare_exchange_n (mem, (void *) &__atg1_oldval, \
54 newval, 1, __ATOMIC_ACQUIRE, \
55 __ATOMIC_RELAXED); \
56 __atg1_oldval; })
57 #define atomic_compare_and_exchange_val_rel(mem, newval, oldval) \
58 ({ __atomic_check_size((mem)); \
59 typeof ((__typeof (*(mem))) *(mem)) __atg1_2_oldval = (oldval); \
60 __atomic_compare_exchange_n (mem, (void *) &__atg1_2_oldval, \
61 newval, 1, __ATOMIC_RELEASE, \
62 __ATOMIC_RELAXED); \
63 __atg1_2_oldval; })
64
65 /* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
66 Return zero if *MEM was changed or non-zero if no exchange happened. */
67 #define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
68 ({ __atomic_check_size((mem)); \
69 typeof ((__typeof (*(mem))) *(mem)) __atg2_oldval = (oldval); \
70 !__atomic_compare_exchange_n (mem, (void *) &__atg2_oldval, newval, \
71 1, __ATOMIC_ACQUIRE, \
72 __ATOMIC_RELAXED); })
73 #define catomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
74 atomic_compare_and_exchange_bool_acq (mem, newval, oldval)
75
76 /* Store NEWVALUE in *MEM and return the old value. */
77 #define atomic_exchange_acq(mem, newvalue) \
78 ({ __atomic_check_size((mem)); \
79 __atomic_exchange_n (mem, newvalue, __ATOMIC_ACQUIRE); })
80 #define atomic_exchange_rel(mem, newvalue) \
81 ({ __atomic_check_size((mem)); \
82 __atomic_exchange_n (mem, newvalue, __ATOMIC_RELEASE); })
83
84 /* Add VALUE to *MEM and return the old value of *MEM. */
85 /* The gcc builtin uses load-and-add instruction on z196 zarch and higher cpus
86 instead of a loop with compare-and-swap instruction. */
87 # define atomic_exchange_and_add_acq(mem, operand) \
88 ({ __atomic_check_size((mem)); \
89 __atomic_fetch_add ((mem), (operand), __ATOMIC_ACQUIRE); })
90 # define atomic_exchange_and_add_rel(mem, operand) \
91 ({ __atomic_check_size((mem)); \
92 __atomic_fetch_add ((mem), (operand), __ATOMIC_RELEASE); })
93 #define catomic_exchange_and_add(mem, value) \
94 atomic_exchange_and_add (mem, value)
95
96 /* Atomically *mem |= mask and return the old value of *mem. */
97 /* The gcc builtin uses load-and-or instruction on z196 zarch and higher cpus
98 instead of a loop with compare-and-swap instruction. */
99 #define atomic_or_val(mem, operand) \
100 ({ __atomic_check_size((mem)); \
101 __atomic_fetch_or ((mem), (operand), __ATOMIC_ACQUIRE); })
102 /* Atomically *mem |= mask. */
103 #define atomic_or(mem, mask) \
104 do { \
105 atomic_or_val (mem, mask); \
106 } while (0)
107 #define catomic_or(mem, mask) \
108 atomic_or (mem, mask)
109
110 /* Atomically *mem |= 1 << bit and return true if the bit was set in old value
111 of *mem. */
112 /* The load-and-or instruction is used on z196 zarch and higher cpus
113 instead of a loop with compare-and-swap instruction. */
114 #define atomic_bit_test_set(mem, bit) \
115 ({ __typeof (*(mem)) __atg14_old; \
116 __typeof (mem) __atg14_memp = (mem); \
117 __typeof (*(mem)) __atg14_mask = ((__typeof (*(mem))) 1 << (bit)); \
118 __atg14_old = atomic_or_val (__atg14_memp, __atg14_mask); \
119 __atg14_old & __atg14_mask; })
120
121 /* Atomically *mem &= mask and return the old value of *mem. */
122 /* The gcc builtin uses load-and-and instruction on z196 zarch and higher cpus
123 instead of a loop with compare-and-swap instruction. */
124 #define atomic_and_val(mem, operand) \
125 ({ __atomic_check_size((mem)); \
126 __atomic_fetch_and ((mem), (operand), __ATOMIC_ACQUIRE); })
127 /* Atomically *mem &= mask. */
128 #define atomic_and(mem, mask) \
129 do { \
130 atomic_and_val (mem, mask); \
131 } while (0)
132 #define catomic_and(mem, mask) \
133 atomic_and(mem, mask)