1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_ATOMIC_H 3 #define _ASM_X86_ATOMIC_H 4 5 #include <linux/compiler.h> 6 #include <linux/types.h> 7 #include <asm/alternative.h> 8 #include <asm/cmpxchg.h> 9 #include <asm/rmwcc.h> 10 #include <asm/barrier.h> 11 12 /* 13 * Atomic operations that C can't guarantee us. Useful for 14 * resource counting etc.. 15 */ 16 17 /** 18 * arch_atomic_read - read atomic variable 19 * @v: pointer of type atomic_t 20 * 21 * Atomically reads the value of @v. 22 */ 23 static __always_inline int arch_atomic_read(const atomic_t *v) 24 { 25 /* 26 * Note for KASAN: we deliberately don't use READ_ONCE_NOCHECK() here, 27 * it's non-inlined function that increases binary size and stack usage. 28 */ 29 return __READ_ONCE((v)->counter); 30 } 31 32 /** 33 * arch_atomic_set - set atomic variable 34 * @v: pointer of type atomic_t 35 * @i: required value 36 * 37 * Atomically sets the value of @v to @i. 38 */ 39 static __always_inline void arch_atomic_set(atomic_t *v, int i) 40 { 41 __WRITE_ONCE(v->counter, i); 42 } 43 44 /** 45 * arch_atomic_add - add integer to atomic variable 46 * @i: integer value to add 47 * @v: pointer of type atomic_t 48 * 49 * Atomically adds @i to @v. 50 */ 51 static __always_inline void arch_atomic_add(int i, atomic_t *v) 52 { 53 asm volatile(LOCK_PREFIX "addl %1,%0" 54 : "+m" (v->counter) 55 : "ir" (i) : "memory"); 56 } 57 58 /** 59 * arch_atomic_sub - subtract integer from atomic variable 60 * @i: integer value to subtract 61 * @v: pointer of type atomic_t 62 * 63 * Atomically subtracts @i from @v. 64 */ 65 static __always_inline void arch_atomic_sub(int i, atomic_t *v) 66 { 67 asm volatile(LOCK_PREFIX "subl %1,%0" 68 : "+m" (v->counter) 69 : "ir" (i) : "memory"); 70 } 71 72 /** 73 * arch_atomic_sub_and_test - subtract value from variable and test result 74 * @i: integer value to subtract 75 * @v: pointer of type atomic_t 76 * 77 * Atomically subtracts @i from @v and returns 78 * true if the result is zero, or false for all 79 * other cases. 80 */ 81 static __always_inline bool arch_atomic_sub_and_test(int i, atomic_t *v) 82 { 83 return GEN_BINARY_RMWcc(LOCK_PREFIX "subl", v->counter, e, "er", i); 84 } 85 #define arch_atomic_sub_and_test arch_atomic_sub_and_test 86 87 /** 88 * arch_atomic_inc - increment atomic variable 89 * @v: pointer of type atomic_t 90 * 91 * Atomically increments @v by 1. 92 */ 93 static __always_inline void arch_atomic_inc(atomic_t *v) 94 { 95 asm volatile(LOCK_PREFIX "incl %0" 96 : "+m" (v->counter) :: "memory"); 97 } 98 #define arch_atomic_inc arch_atomic_inc 99 100 /** 101 * arch_atomic_dec - decrement atomic variable 102 * @v: pointer of type atomic_t 103 * 104 * Atomically decrements @v by 1. 105 */ 106 static __always_inline void arch_atomic_dec(atomic_t *v) 107 { 108 asm volatile(LOCK_PREFIX "decl %0" 109 : "+m" (v->counter) :: "memory"); 110 } 111 #define arch_atomic_dec arch_atomic_dec 112 113 /** 114 * arch_atomic_dec_and_test - decrement and test 115 * @v: pointer of type atomic_t 116 * 117 * Atomically decrements @v by 1 and 118 * returns true if the result is 0, or false for all other 119 * cases. 120 */ 121 static __always_inline bool arch_atomic_dec_and_test(atomic_t *v) 122 { 123 return GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, e); 124 } 125 #define arch_atomic_dec_and_test arch_atomic_dec_and_test 126 127 /** 128 * arch_atomic_inc_and_test - increment and test 129 * @v: pointer of type atomic_t 130 * 131 * Atomically increments @v by 1 132 * and returns true if the result is zero, or false for all 133 * other cases. 134 */ 135 static __always_inline bool arch_atomic_inc_and_test(atomic_t *v) 136 { 137 return GEN_UNARY_RMWcc(LOCK_PREFIX "incl", v->counter, e); 138 } 139 #define arch_atomic_inc_and_test arch_atomic_inc_and_test 140 141 /** 142 * arch_atomic_add_negative - add and test if negative 143 * @i: integer value to add 144 * @v: pointer of type atomic_t 145 * 146 * Atomically adds @i to @v and returns true 147 * if the result is negative, or false when 148 * result is greater than or equal to zero. 149 */ 150 static __always_inline bool arch_atomic_add_negative(int i, atomic_t *v) 151 { 152 return GEN_BINARY_RMWcc(LOCK_PREFIX "addl", v->counter, s, "er", i); 153 } 154 #define arch_atomic_add_negative arch_atomic_add_negative 155 156 /** 157 * arch_atomic_add_return - add integer and return 158 * @i: integer value to add 159 * @v: pointer of type atomic_t 160 * 161 * Atomically adds @i to @v and returns @i + @v 162 */ 163 static __always_inline int arch_atomic_add_return(int i, atomic_t *v) 164 { 165 return i + xadd(&v->counter, i); 166 } 167 #define arch_atomic_add_return arch_atomic_add_return 168 169 /** 170 * arch_atomic_sub_return - subtract integer and return 171 * @v: pointer of type atomic_t 172 * @i: integer value to subtract 173 * 174 * Atomically subtracts @i from @v and returns @v - @i 175 */ 176 static __always_inline int arch_atomic_sub_return(int i, atomic_t *v) 177 { 178 return arch_atomic_add_return(-i, v); 179 } 180 #define arch_atomic_sub_return arch_atomic_sub_return 181 182 static __always_inline int arch_atomic_fetch_add(int i, atomic_t *v) 183 { 184 return xadd(&v->counter, i); 185 } 186 #define arch_atomic_fetch_add arch_atomic_fetch_add 187 188 static __always_inline int arch_atomic_fetch_sub(int i, atomic_t *v) 189 { 190 return xadd(&v->counter, -i); 191 } 192 #define arch_atomic_fetch_sub arch_atomic_fetch_sub 193 194 static __always_inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new) 195 { 196 return arch_cmpxchg(&v->counter, old, new); 197 } 198 #define arch_atomic_cmpxchg arch_atomic_cmpxchg 199 200 static __always_inline bool arch_atomic_try_cmpxchg(atomic_t *v, int *old, int new) 201 { 202 return try_cmpxchg(&v->counter, old, new); 203 } 204 #define arch_atomic_try_cmpxchg arch_atomic_try_cmpxchg 205 206 static __always_inline int arch_atomic_xchg(atomic_t *v, int new) 207 { 208 return arch_xchg(&v->counter, new); 209 } 210 #define arch_atomic_xchg arch_atomic_xchg 211 212 static __always_inline void arch_atomic_and(int i, atomic_t *v) 213 { 214 asm volatile(LOCK_PREFIX "andl %1,%0" 215 : "+m" (v->counter) 216 : "ir" (i) 217 : "memory"); 218 } 219 220 static __always_inline int arch_atomic_fetch_and(int i, atomic_t *v) 221 { 222 int val = arch_atomic_read(v); 223 224 do { } while (!arch_atomic_try_cmpxchg(v, &val, val & i)); 225 226 return val; 227 } 228 #define arch_atomic_fetch_and arch_atomic_fetch_and 229 230 static __always_inline void arch_atomic_or(int i, atomic_t *v) 231 { 232 asm volatile(LOCK_PREFIX "orl %1,%0" 233 : "+m" (v->counter) 234 : "ir" (i) 235 : "memory"); 236 } 237 238 static __always_inline int arch_atomic_fetch_or(int i, atomic_t *v) 239 { 240 int val = arch_atomic_read(v); 241 242 do { } while (!arch_atomic_try_cmpxchg(v, &val, val | i)); 243 244 return val; 245 } 246 #define arch_atomic_fetch_or arch_atomic_fetch_or 247 248 static __always_inline void arch_atomic_xor(int i, atomic_t *v) 249 { 250 asm volatile(LOCK_PREFIX "xorl %1,%0" 251 : "+m" (v->counter) 252 : "ir" (i) 253 : "memory"); 254 } 255 256 static __always_inline int arch_atomic_fetch_xor(int i, atomic_t *v) 257 { 258 int val = arch_atomic_read(v); 259 260 do { } while (!arch_atomic_try_cmpxchg(v, &val, val ^ i)); 261 262 return val; 263 } 264 #define arch_atomic_fetch_xor arch_atomic_fetch_xor 265 266 #ifdef CONFIG_X86_32 267 # include <asm/atomic64_32.h> 268 #else 269 # include <asm/atomic64_64.h> 270 #endif 271 272 #define ARCH_ATOMIC 273 274 #endif /* _ASM_X86_ATOMIC_H */ 275