1 #ifndef _ASM_X86_LOCAL_H 2 #define _ASM_X86_LOCAL_H 3 4 #include <linux/percpu.h> 5 6 #include <asm/system.h> 7 #include <asm/atomic.h> 8 #include <asm/asm.h> 9 10 typedef struct { 11 atomic_long_t a; 12 } local_t; 13 14 #define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) } 15 16 #define local_read(l) atomic_long_read(&(l)->a) 17 #define local_set(l, i) atomic_long_set(&(l)->a, (i)) 18 19 static inline void local_inc(local_t *l) 20 { 21 asm volatile(_ASM_INC "%0" 22 : "+m" (l->a.counter)); 23 } 24 25 static inline void local_dec(local_t *l) 26 { 27 asm volatile(_ASM_DEC "%0" 28 : "+m" (l->a.counter)); 29 } 30 31 static inline void local_add(long i, local_t *l) 32 { 33 asm volatile(_ASM_ADD "%1,%0" 34 : "+m" (l->a.counter) 35 : "ir" (i)); 36 } 37 38 static inline void local_sub(long i, local_t *l) 39 { 40 asm volatile(_ASM_SUB "%1,%0" 41 : "+m" (l->a.counter) 42 : "ir" (i)); 43 } 44 45 /** 46 * local_sub_and_test - subtract value from variable and test result 47 * @i: integer value to subtract 48 * @l: pointer to type local_t 49 * 50 * Atomically subtracts @i from @l and returns 51 * true if the result is zero, or false for all 52 * other cases. 53 */ 54 static inline int local_sub_and_test(long i, local_t *l) 55 { 56 unsigned char c; 57 58 asm volatile(_ASM_SUB "%2,%0; sete %1" 59 : "+m" (l->a.counter), "=qm" (c) 60 : "ir" (i) : "memory"); 61 return c; 62 } 63 64 /** 65 * local_dec_and_test - decrement and test 66 * @l: pointer to type local_t 67 * 68 * Atomically decrements @l by 1 and 69 * returns true if the result is 0, or false for all other 70 * cases. 71 */ 72 static inline int local_dec_and_test(local_t *l) 73 { 74 unsigned char c; 75 76 asm volatile(_ASM_DEC "%0; sete %1" 77 : "+m" (l->a.counter), "=qm" (c) 78 : : "memory"); 79 return c != 0; 80 } 81 82 /** 83 * local_inc_and_test - increment and test 84 * @l: pointer to type local_t 85 * 86 * Atomically increments @l by 1 87 * and returns true if the result is zero, or false for all 88 * other cases. 89 */ 90 static inline int local_inc_and_test(local_t *l) 91 { 92 unsigned char c; 93 94 asm volatile(_ASM_INC "%0; sete %1" 95 : "+m" (l->a.counter), "=qm" (c) 96 : : "memory"); 97 return c != 0; 98 } 99 100 /** 101 * local_add_negative - add and test if negative 102 * @i: integer value to add 103 * @l: pointer to type local_t 104 * 105 * Atomically adds @i to @l and returns true 106 * if the result is negative, or false when 107 * result is greater than or equal to zero. 108 */ 109 static inline int local_add_negative(long i, local_t *l) 110 { 111 unsigned char c; 112 113 asm volatile(_ASM_ADD "%2,%0; sets %1" 114 : "+m" (l->a.counter), "=qm" (c) 115 : "ir" (i) : "memory"); 116 return c; 117 } 118 119 /** 120 * local_add_return - add and return 121 * @i: integer value to add 122 * @l: pointer to type local_t 123 * 124 * Atomically adds @i to @l and returns @i + @l 125 */ 126 static inline long local_add_return(long i, local_t *l) 127 { 128 long __i; 129 #ifdef CONFIG_M386 130 unsigned long flags; 131 if (unlikely(boot_cpu_data.x86 <= 3)) 132 goto no_xadd; 133 #endif 134 /* Modern 486+ processor */ 135 __i = i; 136 asm volatile(_ASM_XADD "%0, %1;" 137 : "+r" (i), "+m" (l->a.counter) 138 : : "memory"); 139 return i + __i; 140 141 #ifdef CONFIG_M386 142 no_xadd: /* Legacy 386 processor */ 143 local_irq_save(flags); 144 __i = local_read(l); 145 local_set(l, i + __i); 146 local_irq_restore(flags); 147 return i + __i; 148 #endif 149 } 150 151 static inline long local_sub_return(long i, local_t *l) 152 { 153 return local_add_return(-i, l); 154 } 155 156 #define local_inc_return(l) (local_add_return(1, l)) 157 #define local_dec_return(l) (local_sub_return(1, l)) 158 159 #define local_cmpxchg(l, o, n) \ 160 (cmpxchg_local(&((l)->a.counter), (o), (n))) 161 /* Always has a lock prefix */ 162 #define local_xchg(l, n) (xchg(&((l)->a.counter), (n))) 163 164 /** 165 * local_add_unless - add unless the number is a given value 166 * @l: pointer of type local_t 167 * @a: the amount to add to l... 168 * @u: ...unless l is equal to u. 169 * 170 * Atomically adds @a to @l, so long as it was not @u. 171 * Returns non-zero if @l was not @u, and zero otherwise. 172 */ 173 #define local_add_unless(l, a, u) \ 174 ({ \ 175 long c, old; \ 176 c = local_read((l)); \ 177 for (;;) { \ 178 if (unlikely(c == (u))) \ 179 break; \ 180 old = local_cmpxchg((l), c, c + (a)); \ 181 if (likely(old == c)) \ 182 break; \ 183 c = old; \ 184 } \ 185 c != (u); \ 186 }) 187 #define local_inc_not_zero(l) local_add_unless((l), 1, 0) 188 189 /* On x86_32, these are no better than the atomic variants. 190 * On x86-64 these are better than the atomic variants on SMP kernels 191 * because they dont use a lock prefix. 192 */ 193 #define __local_inc(l) local_inc(l) 194 #define __local_dec(l) local_dec(l) 195 #define __local_add(i, l) local_add((i), (l)) 196 #define __local_sub(i, l) local_sub((i), (l)) 197 198 /* Use these for per-cpu local_t variables: on some archs they are 199 * much more efficient than these naive implementations. Note they take 200 * a variable, not an address. 201 * 202 * X86_64: This could be done better if we moved the per cpu data directly 203 * after GS. 204 */ 205 206 /* Need to disable preemption for the cpu local counters otherwise we could 207 still access a variable of a previous CPU in a non atomic way. */ 208 #define cpu_local_wrap_v(l) \ 209 ({ \ 210 local_t res__; \ 211 preempt_disable(); \ 212 res__ = (l); \ 213 preempt_enable(); \ 214 res__; \ 215 }) 216 #define cpu_local_wrap(l) \ 217 ({ \ 218 preempt_disable(); \ 219 (l); \ 220 preempt_enable(); \ 221 }) \ 222 223 #define cpu_local_read(l) cpu_local_wrap_v(local_read(&__get_cpu_var((l)))) 224 #define cpu_local_set(l, i) cpu_local_wrap(local_set(&__get_cpu_var((l)), (i))) 225 #define cpu_local_inc(l) cpu_local_wrap(local_inc(&__get_cpu_var((l)))) 226 #define cpu_local_dec(l) cpu_local_wrap(local_dec(&__get_cpu_var((l)))) 227 #define cpu_local_add(i, l) cpu_local_wrap(local_add((i), &__get_cpu_var((l)))) 228 #define cpu_local_sub(i, l) cpu_local_wrap(local_sub((i), &__get_cpu_var((l)))) 229 230 #define __cpu_local_inc(l) cpu_local_inc((l)) 231 #define __cpu_local_dec(l) cpu_local_dec((l)) 232 #define __cpu_local_add(i, l) cpu_local_add((i), (l)) 233 #define __cpu_local_sub(i, l) cpu_local_sub((i), (l)) 234 235 #endif /* _ASM_X86_LOCAL_H */ 236