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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 :
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 0 : asm volatile(_ASM_INC "%0"
22 : : "+m" (l->a.counter));
23 : }
24 :
25 : static inline void local_dec(local_t *l)
26 : {
27 0 : 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 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 : */
67 : static 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 : */
80 : static 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 : */
94 : static 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 : */
106 : static 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 :
115 : static 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 :
123 : static inline long local_cmpxchg(local_t *l, long old, long new)
124 : {
125 : return cmpxchg_local(&l->a.counter, old, new);
126 : }
127 :
128 : static inline bool local_try_cmpxchg(local_t *l, long *old, long new)
129 : {
130 : typeof(l->a.counter) *__old = (typeof(l->a.counter) *) old;
131 : return try_cmpxchg_local(&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 */
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