1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _ASM_X86_LOCAL_H 3#define _ASM_X86_LOCAL_H 4 5#include <linux/percpu.h> 6 7#include <linux/atomic.h> 8#include <asm/asm.h> 9 10typedef 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 19static inline void local_inc(local_t *l) 20{ 21 asm volatile(_ASM_INC "%0" 22 : "+m" (l->a.counter)); 23} 24 25static inline void local_dec(local_t *l) 26{ 27 asm volatile(_ASM_DEC "%0" 28 : "+m" (l->a.counter)); 29} 30 31static 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 38static 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 */ 54static inline bool local_sub_and_test(long i, local_t *l) 55{ 56 return GEN_BINARY_RMWcc(_ASM_SUB, l->a.counter, e, "er", i); 57} 58 59/** 60 * local_dec_and_test - decrement and test 61 * @l: pointer to type local_t 62 * 63 * Atomically decrements @l by 1 and 64 * returns true if the result is 0, or false for all other 65 * cases. 66 */ 67static inline bool local_dec_and_test(local_t *l) 68{ 69 return GEN_UNARY_RMWcc(_ASM_DEC, l->a.counter, e); 70} 71 72/** 73 * local_inc_and_test - increment and test 74 * @l: pointer to type local_t 75 * 76 * Atomically increments @l by 1 77 * and returns true if the result is zero, or false for all 78 * other cases. 79 */ 80static inline bool local_inc_and_test(local_t *l) 81{ 82 return GEN_UNARY_RMWcc(_ASM_INC, l->a.counter, e); 83} 84 85/** 86 * local_add_negative - add and test if negative 87 * @i: integer value to add 88 * @l: pointer to type local_t 89 * 90 * Atomically adds @i to @l and returns true 91 * if the result is negative, or false when 92 * result is greater than or equal to zero. 93 */ 94static inline bool local_add_negative(long i, local_t *l) 95{ 96 return GEN_BINARY_RMWcc(_ASM_ADD, l->a.counter, s, "er", i); 97} 98 99/** 100 * local_add_return - add and return 101 * @i: integer value to add 102 * @l: pointer to type local_t 103 * 104 * Atomically adds @i to @l and returns @i + @l 105 */ 106static inline long local_add_return(long i, local_t *l) 107{ 108 long __i = i; 109 asm volatile(_ASM_XADD "%0, %1;" 110 : "+r" (i), "+m" (l->a.counter) 111 : : "memory"); 112 return i + __i; 113} 114 115static inline long local_sub_return(long i, local_t *l) 116{ 117 return local_add_return(-i, l); 118} 119 120#define local_inc_return(l) (local_add_return(1, l)) 121#define local_dec_return(l) (local_sub_return(1, l)) 122 123static inline long local_cmpxchg(local_t *l, long old, long new) 124{ 125 return cmpxchg_local(&l->a.counter, old, new); 126} 127 128static inline bool local_try_cmpxchg(local_t *l, long *old, long new) 129{ 130 return try_cmpxchg_local(&l->a.counter, 131 (typeof(l->a.counter) *) old, new); 132} 133 134/* Always has a lock prefix */ 135#define local_xchg(l, n) (xchg(&((l)->a.counter), (n))) 136 137/** 138 * local_add_unless - add unless the number is a given value 139 * @l: pointer of type local_t 140 * @a: the amount to add to l... 141 * @u: ...unless l is equal to u. 142 * 143 * Atomically adds @a to @l, so long as it was not @u. 144 * Returns non-zero if @l was not @u, and zero otherwise. 145 */ 146#define local_add_unless(l, a, u) \ 147({ \ 148 long c, old; \ 149 c = local_read((l)); \ 150 for (;;) { \ 151 if (unlikely(c == (u))) \ 152 break; \ 153 old = local_cmpxchg((l), c, c + (a)); \ 154 if (likely(old == c)) \ 155 break; \ 156 c = old; \ 157 } \ 158 c != (u); \ 159}) 160#define local_inc_not_zero(l) local_add_unless((l), 1, 0) 161 162/* On x86_32, these are no better than the atomic variants. 163 * On x86-64 these are better than the atomic variants on SMP kernels 164 * because they dont use a lock prefix. 165 */ 166#define __local_inc(l) local_inc(l) 167#define __local_dec(l) local_dec(l) 168#define __local_add(i, l) local_add((i), (l)) 169#define __local_sub(i, l) local_sub((i), (l)) 170 171#endif /* _ASM_X86_LOCAL_H */ 172