Ingo Molnar | b7882b7 | 2009-07-03 13:26:39 +0200 | [diff] [blame^] | 1 | #include <linux/compiler.h> |
| 2 | #include <linux/types.h> |
| 3 | #include <asm/processor.h> |
| 4 | #include <asm/cmpxchg.h> |
| 5 | #include <asm/atomic.h> |
| 6 | |
| 7 | static inline u64 cmpxchg8b(u64 *ptr, u64 old, u64 new) |
| 8 | { |
| 9 | asm volatile( |
| 10 | |
| 11 | LOCK_PREFIX "cmpxchg8b (%[ptr])\n" |
| 12 | |
| 13 | : "=A" (old) |
| 14 | |
| 15 | : [ptr] "D" (ptr), |
| 16 | "A" (old), |
| 17 | "b" (ll_low(new)), |
| 18 | "c" (ll_high(new)) |
| 19 | |
| 20 | : "memory"); |
| 21 | |
| 22 | return old; |
| 23 | } |
| 24 | |
| 25 | u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val) |
| 26 | { |
| 27 | return cmpxchg8b(&ptr->counter, old_val, new_val); |
| 28 | } |
| 29 | |
| 30 | /** |
| 31 | * atomic64_xchg - xchg atomic64 variable |
| 32 | * @ptr: pointer to type atomic64_t |
| 33 | * @new_val: value to assign |
| 34 | * |
| 35 | * Atomically xchgs the value of @ptr to @new_val and returns |
| 36 | * the old value. |
| 37 | */ |
| 38 | |
| 39 | u64 atomic64_xchg(atomic64_t *ptr, u64 new_val) |
| 40 | { |
| 41 | u64 old_val; |
| 42 | |
| 43 | do { |
| 44 | old_val = atomic_read(ptr); |
| 45 | } while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val); |
| 46 | |
| 47 | return old_val; |
| 48 | } |
| 49 | |
| 50 | /** |
| 51 | * atomic64_set - set atomic64 variable |
| 52 | * @ptr: pointer to type atomic64_t |
| 53 | * @new_val: value to assign |
| 54 | * |
| 55 | * Atomically sets the value of @ptr to @new_val. |
| 56 | */ |
| 57 | void atomic64_set(atomic64_t *ptr, u64 new_val) |
| 58 | { |
| 59 | atomic64_xchg(ptr, new_val); |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * atomic64_read - read atomic64 variable |
| 64 | * @ptr: pointer to type atomic64_t |
| 65 | * |
| 66 | * Atomically reads the value of @ptr and returns it. |
| 67 | */ |
| 68 | u64 atomic64_read(atomic64_t *ptr) |
| 69 | { |
| 70 | u64 curr_val; |
| 71 | |
| 72 | do { |
| 73 | curr_val = __atomic64_read(ptr); |
| 74 | } while (atomic64_cmpxchg(ptr, curr_val, curr_val) != curr_val); |
| 75 | |
| 76 | return curr_val; |
| 77 | } |
| 78 | |
| 79 | /** |
| 80 | * atomic64_add_return - add and return |
| 81 | * @delta: integer value to add |
| 82 | * @ptr: pointer to type atomic64_t |
| 83 | * |
| 84 | * Atomically adds @delta to @ptr and returns @delta + *@ptr |
| 85 | */ |
| 86 | u64 atomic64_add_return(u64 delta, atomic64_t *ptr) |
| 87 | { |
| 88 | u64 old_val, new_val; |
| 89 | |
| 90 | do { |
| 91 | old_val = atomic_read(ptr); |
| 92 | new_val = old_val + delta; |
| 93 | |
| 94 | } while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val); |
| 95 | |
| 96 | return new_val; |
| 97 | } |
| 98 | |
| 99 | u64 atomic64_sub_return(u64 delta, atomic64_t *ptr) |
| 100 | { |
| 101 | return atomic64_add_return(-delta, ptr); |
| 102 | } |
| 103 | |
| 104 | u64 atomic64_inc_return(atomic64_t *ptr) |
| 105 | { |
| 106 | return atomic64_add_return(1, ptr); |
| 107 | } |
| 108 | |
| 109 | u64 atomic64_dec_return(atomic64_t *ptr) |
| 110 | { |
| 111 | return atomic64_sub_return(1, ptr); |
| 112 | } |
| 113 | |
| 114 | /** |
| 115 | * atomic64_add - add integer to atomic64 variable |
| 116 | * @delta: integer value to add |
| 117 | * @ptr: pointer to type atomic64_t |
| 118 | * |
| 119 | * Atomically adds @delta to @ptr. |
| 120 | */ |
| 121 | void atomic64_add(u64 delta, atomic64_t *ptr) |
| 122 | { |
| 123 | atomic64_add_return(delta, ptr); |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * atomic64_sub - subtract the atomic64 variable |
| 128 | * @delta: integer value to subtract |
| 129 | * @ptr: pointer to type atomic64_t |
| 130 | * |
| 131 | * Atomically subtracts @delta from @ptr. |
| 132 | */ |
| 133 | void atomic64_sub(u64 delta, atomic64_t *ptr) |
| 134 | { |
| 135 | atomic64_add(-delta, ptr); |
| 136 | } |
| 137 | |
| 138 | /** |
| 139 | * atomic64_sub_and_test - subtract value from variable and test result |
| 140 | * @delta: integer value to subtract |
| 141 | * @ptr: pointer to type atomic64_t |
| 142 | * |
| 143 | * Atomically subtracts @delta from @ptr and returns |
| 144 | * true if the result is zero, or false for all |
| 145 | * other cases. |
| 146 | */ |
| 147 | int atomic64_sub_and_test(u64 delta, atomic64_t *ptr) |
| 148 | { |
| 149 | u64 old_val = atomic64_sub_return(delta, ptr); |
| 150 | |
| 151 | return old_val == 0; |
| 152 | } |
| 153 | |
| 154 | /** |
| 155 | * atomic64_inc - increment atomic64 variable |
| 156 | * @ptr: pointer to type atomic64_t |
| 157 | * |
| 158 | * Atomically increments @ptr by 1. |
| 159 | */ |
| 160 | void atomic64_inc(atomic64_t *ptr) |
| 161 | { |
| 162 | atomic64_add(1, ptr); |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * atomic64_dec - decrement atomic64 variable |
| 167 | * @ptr: pointer to type atomic64_t |
| 168 | * |
| 169 | * Atomically decrements @ptr by 1. |
| 170 | */ |
| 171 | void atomic64_dec(atomic64_t *ptr) |
| 172 | { |
| 173 | atomic64_sub(1, ptr); |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * atomic64_dec_and_test - decrement and test |
| 178 | * @ptr: pointer to type atomic64_t |
| 179 | * |
| 180 | * Atomically decrements @ptr by 1 and |
| 181 | * returns true if the result is 0, or false for all other |
| 182 | * cases. |
| 183 | */ |
| 184 | int atomic64_dec_and_test(atomic64_t *ptr) |
| 185 | { |
| 186 | return atomic64_sub_and_test(1, ptr); |
| 187 | } |
| 188 | |
| 189 | /** |
| 190 | * atomic64_inc_and_test - increment and test |
| 191 | * @ptr: pointer to type atomic64_t |
| 192 | * |
| 193 | * Atomically increments @ptr by 1 |
| 194 | * and returns true if the result is zero, or false for all |
| 195 | * other cases. |
| 196 | */ |
| 197 | int atomic64_inc_and_test(atomic64_t *ptr) |
| 198 | { |
| 199 | return atomic64_sub_and_test(-1, ptr); |
| 200 | } |
| 201 | |
| 202 | /** |
| 203 | * atomic64_add_negative - add and test if negative |
| 204 | * @delta: integer value to add |
| 205 | * @ptr: pointer to type atomic64_t |
| 206 | * |
| 207 | * Atomically adds @delta to @ptr and returns true |
| 208 | * if the result is negative, or false when |
| 209 | * result is greater than or equal to zero. |
| 210 | */ |
| 211 | int atomic64_add_negative(u64 delta, atomic64_t *ptr) |
| 212 | { |
| 213 | long long old_val = atomic64_add_return(delta, ptr); |
| 214 | |
| 215 | return old_val < 0; |
| 216 | } |