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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 | /* * Based on arch/arm/include/asm/cmpxchg.h * * Copyright (C) 2012 ARM Ltd. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #ifndef __ASM_CMPXCHG_H #define __ASM_CMPXCHG_H #include <linux/bug.h> #include <asm/barrier.h> static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size) { unsigned long ret, tmp; switch (size) { case 1: asm volatile("// __xchg1\n" "1: ldaxrb %w0, %2\n" " stlxrb %w1, %w3, %2\n" " cbnz %w1, 1b\n" : "=&r" (ret), "=&r" (tmp), "+Q" (*(u8 *)ptr) : "r" (x) : "cc", "memory"); break; case 2: asm volatile("// __xchg2\n" "1: ldaxrh %w0, %2\n" " stlxrh %w1, %w3, %2\n" " cbnz %w1, 1b\n" : "=&r" (ret), "=&r" (tmp), "+Q" (*(u16 *)ptr) : "r" (x) : "cc", "memory"); break; case 4: asm volatile("// __xchg4\n" "1: ldaxr %w0, %2\n" " stlxr %w1, %w3, %2\n" " cbnz %w1, 1b\n" : "=&r" (ret), "=&r" (tmp), "+Q" (*(u32 *)ptr) : "r" (x) : "cc", "memory"); break; case 8: asm volatile("// __xchg8\n" "1: ldaxr %0, %2\n" " stlxr %w1, %3, %2\n" " cbnz %w1, 1b\n" : "=&r" (ret), "=&r" (tmp), "+Q" (*(u64 *)ptr) : "r" (x) : "cc", "memory"); break; default: BUILD_BUG(); } return ret; } #define xchg(ptr,x) \ ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) { unsigned long oldval = 0, res; switch (size) { case 1: do { asm volatile("// __cmpxchg1\n" " ldxrb %w1, %2\n" " mov %w0, #0\n" " cmp %w1, %w3\n" " b.ne 1f\n" " stxrb %w0, %w4, %2\n" "1:\n" : "=&r" (res), "=&r" (oldval), "+Q" (*(u8 *)ptr) : "Ir" (old), "r" (new) : "cc"); } while (res); break; case 2: do { asm volatile("// __cmpxchg2\n" " ldxrh %w1, %2\n" " mov %w0, #0\n" " cmp %w1, %w3\n" " b.ne 1f\n" " stxrh %w0, %w4, %2\n" "1:\n" : "=&r" (res), "=&r" (oldval), "+Q" (*(u16 *)ptr) : "Ir" (old), "r" (new) : "cc"); } while (res); break; case 4: do { asm volatile("// __cmpxchg4\n" " ldxr %w1, %2\n" " mov %w0, #0\n" " cmp %w1, %w3\n" " b.ne 1f\n" " stxr %w0, %w4, %2\n" "1:\n" : "=&r" (res), "=&r" (oldval), "+Q" (*(u32 *)ptr) : "Ir" (old), "r" (new) : "cc"); } while (res); break; case 8: do { asm volatile("// __cmpxchg8\n" " ldxr %1, %2\n" " mov %w0, #0\n" " cmp %1, %3\n" " b.ne 1f\n" " stxr %w0, %4, %2\n" "1:\n" : "=&r" (res), "=&r" (oldval), "+Q" (*(u64 *)ptr) : "Ir" (old), "r" (new) : "cc"); } while (res); break; default: BUILD_BUG(); } return oldval; } static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old, unsigned long new, int size) { unsigned long ret; smp_mb(); ret = __cmpxchg(ptr, old, new, size); smp_mb(); return ret; } #define cmpxchg(ptr,o,n) \ ((__typeof__(*(ptr)))__cmpxchg_mb((ptr), \ (unsigned long)(o), \ (unsigned long)(n), \ sizeof(*(ptr)))) #define cmpxchg_local(ptr,o,n) \ ((__typeof__(*(ptr)))__cmpxchg((ptr), \ (unsigned long)(o), \ (unsigned long)(n), \ sizeof(*(ptr)))) #define cmpxchg64(ptr,o,n) cmpxchg((ptr),(o),(n)) #define cmpxchg64_local(ptr,o,n) cmpxchg_local((ptr),(o),(n)) #endif /* __ASM_CMPXCHG_H */ |