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| Rev | Author | Line No. | Line |
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| 5270 | serge | 1 | #ifndef ASM_X86_CMPXCHG_H |
| 2 | #define ASM_X86_CMPXCHG_H |
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| 3 | |||
| 4 | #include |
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| 5 | #include |
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| 6 | |||
| 7 | #define __HAVE_ARCH_CMPXCHG 1 |
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| 8 | |||
| 9 | /* |
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| 10 | * Non-existant functions to indicate usage errors at link time |
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| 11 | * (or compile-time if the compiler implements __compiletime_error(). |
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| 12 | */ |
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| 13 | extern void __xchg_wrong_size(void) |
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| 14 | __compiletime_error("Bad argument size for xchg"); |
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| 15 | extern void __cmpxchg_wrong_size(void) |
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| 16 | __compiletime_error("Bad argument size for cmpxchg"); |
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| 17 | extern void __xadd_wrong_size(void) |
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| 18 | __compiletime_error("Bad argument size for xadd"); |
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| 19 | extern void __add_wrong_size(void) |
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| 20 | __compiletime_error("Bad argument size for add"); |
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| 21 | |||
| 22 | /* |
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| 23 | * Constants for operation sizes. On 32-bit, the 64-bit size it set to |
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| 24 | * -1 because sizeof will never return -1, thereby making those switch |
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| 25 | * case statements guaranteeed dead code which the compiler will |
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| 26 | * eliminate, and allowing the "missing symbol in the default case" to |
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| 27 | * indicate a usage error. |
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| 28 | */ |
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| 29 | #define __X86_CASE_B 1 |
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| 30 | #define __X86_CASE_W 2 |
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| 31 | #define __X86_CASE_L 4 |
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| 32 | #ifdef CONFIG_64BIT |
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| 33 | #define __X86_CASE_Q 8 |
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| 34 | #else |
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| 35 | #define __X86_CASE_Q -1 /* sizeof will never return -1 */ |
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| 36 | #endif |
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| 37 | |||
| 38 | /* |
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| 39 | * An exchange-type operation, which takes a value and a pointer, and |
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| 40 | * returns the old value. |
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| 41 | */ |
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| 42 | #define __xchg_op(ptr, arg, op, lock) \ |
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| 43 | ({ \ |
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| 44 | __typeof__ (*(ptr)) __ret = (arg); \ |
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| 45 | switch (sizeof(*(ptr))) { \ |
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| 46 | case __X86_CASE_B: \ |
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| 47 | asm volatile (lock #op "b %b0, %1\n" \ |
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| 48 | : "+q" (__ret), "+m" (*(ptr)) \ |
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| 49 | : : "memory", "cc"); \ |
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| 50 | break; \ |
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| 51 | case __X86_CASE_W: \ |
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| 52 | asm volatile (lock #op "w %w0, %1\n" \ |
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| 53 | : "+r" (__ret), "+m" (*(ptr)) \ |
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| 54 | : : "memory", "cc"); \ |
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| 55 | break; \ |
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| 56 | case __X86_CASE_L: \ |
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| 57 | asm volatile (lock #op "l %0, %1\n" \ |
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| 58 | : "+r" (__ret), "+m" (*(ptr)) \ |
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| 59 | : : "memory", "cc"); \ |
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| 60 | break; \ |
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| 61 | case __X86_CASE_Q: \ |
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| 62 | asm volatile (lock #op "q %q0, %1\n" \ |
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| 63 | : "+r" (__ret), "+m" (*(ptr)) \ |
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| 64 | : : "memory", "cc"); \ |
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| 65 | break; \ |
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| 66 | default: \ |
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| 67 | __ ## op ## _wrong_size(); \ |
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| 68 | } \ |
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| 69 | __ret; \ |
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| 70 | }) |
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| 71 | |||
| 72 | /* |
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| 73 | * Note: no "lock" prefix even on SMP: xchg always implies lock anyway. |
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| 74 | * Since this is generally used to protect other memory information, we |
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| 75 | * use "asm volatile" and "memory" clobbers to prevent gcc from moving |
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| 76 | * information around. |
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| 77 | */ |
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| 78 | #define xchg(ptr, v) __xchg_op((ptr), (v), xchg, "") |
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| 79 | |||
| 80 | /* |
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| 81 | * Atomic compare and exchange. Compare OLD with MEM, if identical, |
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| 82 | * store NEW in MEM. Return the initial value in MEM. Success is |
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| 83 | * indicated by comparing RETURN with OLD. |
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| 84 | */ |
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| 85 | #define __raw_cmpxchg(ptr, old, new, size, lock) \ |
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| 86 | ({ \ |
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| 87 | __typeof__(*(ptr)) __ret; \ |
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| 88 | __typeof__(*(ptr)) __old = (old); \ |
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| 89 | __typeof__(*(ptr)) __new = (new); \ |
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| 90 | switch (size) { \ |
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| 91 | case __X86_CASE_B: \ |
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| 92 | { \ |
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| 93 | volatile u8 *__ptr = (volatile u8 *)(ptr); \ |
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| 94 | asm volatile(lock "cmpxchgb %2,%1" \ |
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| 95 | : "=a" (__ret), "+m" (*__ptr) \ |
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| 96 | : "q" (__new), "0" (__old) \ |
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| 97 | : "memory"); \ |
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| 98 | break; \ |
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| 99 | } \ |
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| 100 | case __X86_CASE_W: \ |
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| 101 | { \ |
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| 102 | volatile u16 *__ptr = (volatile u16 *)(ptr); \ |
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| 103 | asm volatile(lock "cmpxchgw %2,%1" \ |
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| 104 | : "=a" (__ret), "+m" (*__ptr) \ |
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| 105 | : "r" (__new), "0" (__old) \ |
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| 106 | : "memory"); \ |
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| 107 | break; \ |
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| 108 | } \ |
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| 109 | case __X86_CASE_L: \ |
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| 110 | { \ |
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| 111 | volatile u32 *__ptr = (volatile u32 *)(ptr); \ |
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| 112 | asm volatile(lock "cmpxchgl %2,%1" \ |
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| 113 | : "=a" (__ret), "+m" (*__ptr) \ |
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| 114 | : "r" (__new), "0" (__old) \ |
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| 115 | : "memory"); \ |
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| 116 | break; \ |
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| 117 | } \ |
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| 118 | case __X86_CASE_Q: \ |
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| 119 | { \ |
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| 120 | volatile u64 *__ptr = (volatile u64 *)(ptr); \ |
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| 121 | asm volatile(lock "cmpxchgq %2,%1" \ |
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| 122 | : "=a" (__ret), "+m" (*__ptr) \ |
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| 123 | : "r" (__new), "0" (__old) \ |
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| 124 | : "memory"); \ |
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| 125 | break; \ |
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| 126 | } \ |
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| 127 | default: \ |
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| 128 | __cmpxchg_wrong_size(); \ |
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| 129 | } \ |
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| 130 | __ret; \ |
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| 131 | }) |
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| 132 | |||
| 133 | #define __cmpxchg(ptr, old, new, size) \ |
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| 134 | __raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX) |
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| 135 | |||
| 136 | #define __sync_cmpxchg(ptr, old, new, size) \ |
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| 137 | __raw_cmpxchg((ptr), (old), (new), (size), "lock; ") |
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| 138 | |||
| 139 | #define __cmpxchg_local(ptr, old, new, size) \ |
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| 140 | __raw_cmpxchg((ptr), (old), (new), (size), "") |
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| 141 | |||
| 142 | #ifdef CONFIG_X86_32 |
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| 143 | # include |
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| 144 | #else |
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| 145 | # include |
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| 146 | #endif |
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| 147 | |||
| 148 | #define cmpxchg(ptr, old, new) \ |
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| 149 | __cmpxchg(ptr, old, new, sizeof(*(ptr))) |
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| 150 | |||
| 151 | #define sync_cmpxchg(ptr, old, new) \ |
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| 152 | __sync_cmpxchg(ptr, old, new, sizeof(*(ptr))) |
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| 153 | |||
| 154 | #define cmpxchg_local(ptr, old, new) \ |
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| 155 | __cmpxchg_local(ptr, old, new, sizeof(*(ptr))) |
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| 156 | |||
| 157 | /* |
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| 158 | * xadd() adds "inc" to "*ptr" and atomically returns the previous |
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| 159 | * value of "*ptr". |
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| 160 | * |
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| 161 | * xadd() is locked when multiple CPUs are online |
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| 162 | * xadd_sync() is always locked |
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| 163 | * xadd_local() is never locked |
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| 164 | */ |
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| 165 | #define __xadd(ptr, inc, lock) __xchg_op((ptr), (inc), xadd, lock) |
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| 166 | #define xadd(ptr, inc) __xadd((ptr), (inc), LOCK_PREFIX) |
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| 167 | #define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ") |
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| 168 | #define xadd_local(ptr, inc) __xadd((ptr), (inc), "") |
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| 169 | |||
| 170 | #define __add(ptr, inc, lock) \ |
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| 171 | ({ \ |
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| 172 | __typeof__ (*(ptr)) __ret = (inc); \ |
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| 173 | switch (sizeof(*(ptr))) { \ |
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| 174 | case __X86_CASE_B: \ |
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| 175 | asm volatile (lock "addb %b1, %0\n" \ |
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| 176 | : "+m" (*(ptr)) : "qi" (inc) \ |
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| 177 | : "memory", "cc"); \ |
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| 178 | break; \ |
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| 179 | case __X86_CASE_W: \ |
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| 180 | asm volatile (lock "addw %w1, %0\n" \ |
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| 181 | : "+m" (*(ptr)) : "ri" (inc) \ |
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| 182 | : "memory", "cc"); \ |
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| 183 | break; \ |
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| 184 | case __X86_CASE_L: \ |
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| 185 | asm volatile (lock "addl %1, %0\n" \ |
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| 186 | : "+m" (*(ptr)) : "ri" (inc) \ |
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| 187 | : "memory", "cc"); \ |
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| 188 | break; \ |
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| 189 | case __X86_CASE_Q: \ |
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| 190 | asm volatile (lock "addq %1, %0\n" \ |
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| 191 | : "+m" (*(ptr)) : "ri" (inc) \ |
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| 192 | : "memory", "cc"); \ |
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| 193 | break; \ |
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| 194 | default: \ |
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| 195 | __add_wrong_size(); \ |
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| 196 | } \ |
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| 197 | __ret; \ |
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| 198 | }) |
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| 199 | |||
| 200 | /* |
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| 201 | * add_*() adds "inc" to "*ptr" |
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| 202 | * |
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| 203 | * __add() takes a lock prefix |
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| 204 | * add_smp() is locked when multiple CPUs are online |
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| 205 | * add_sync() is always locked |
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| 206 | */ |
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| 207 | #define add_smp(ptr, inc) __add((ptr), (inc), LOCK_PREFIX) |
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| 208 | #define add_sync(ptr, inc) __add((ptr), (inc), "lock; ") |
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| 209 | |||
| 210 | #define __cmpxchg_double(pfx, p1, p2, o1, o2, n1, n2) \ |
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| 211 | ({ \ |
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| 212 | bool __ret; \ |
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| 213 | __typeof__(*(p1)) __old1 = (o1), __new1 = (n1); \ |
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| 214 | __typeof__(*(p2)) __old2 = (o2), __new2 = (n2); \ |
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| 215 | BUILD_BUG_ON(sizeof(*(p1)) != sizeof(long)); \ |
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| 216 | BUILD_BUG_ON(sizeof(*(p2)) != sizeof(long)); \ |
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| 217 | VM_BUG_ON((unsigned long)(p1) % (2 * sizeof(long))); \ |
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| 218 | VM_BUG_ON((unsigned long)((p1) + 1) != (unsigned long)(p2)); \ |
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| 219 | asm volatile(pfx "cmpxchg%c4b %2; sete %0" \ |
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| 220 | : "=a" (__ret), "+d" (__old2), \ |
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| 221 | "+m" (*(p1)), "+m" (*(p2)) \ |
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| 222 | : "i" (2 * sizeof(long)), "a" (__old1), \ |
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| 223 | "b" (__new1), "c" (__new2)); \ |
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| 224 | __ret; \ |
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| 225 | }) |
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| 226 | |||
| 227 | #define cmpxchg_double(p1, p2, o1, o2, n1, n2) \ |
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| 228 | __cmpxchg_double(LOCK_PREFIX, p1, p2, o1, o2, n1, n2) |
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| 229 | |||
| 230 | #define cmpxchg_double_local(p1, p2, o1, o2, n1, n2) \ |
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| 231 | __cmpxchg_double(, p1, p2, o1, o2, n1, n2) |
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| 232 | |||
| 233 | #endif /* ASM_X86_CMPXCHG_H */ |