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1#ifndef _ASM_X86_ATOMIC_H
2#define _ASM_X86_ATOMIC_H
3
4#include <linux/compiler.h>
5#include <linux/types.h>
6#include <asm/alternative.h>
7#include <asm/cmpxchg.h>
8#include <asm/rmwcc.h>
9#include <asm/barrier.h>
10
11/*
12 * Atomic operations that C can't guarantee us. Useful for
13 * resource counting etc..
14 */
15
16#define ATOMIC_INIT(i) { (i) }
17
18/**
19 * atomic_read - read atomic variable
20 * @v: pointer of type atomic_t
21 *
22 * Atomically reads the value of @v.
23 */
24static __always_inline int atomic_read(const atomic_t *v)
25{
26 return READ_ONCE((v)->counter);
27}
28
29/**
30 * atomic_set - set atomic variable
31 * @v: pointer of type atomic_t
32 * @i: required value
33 *
34 * Atomically sets the value of @v to @i.
35 */
36static __always_inline void atomic_set(atomic_t *v, int i)
37{
38 WRITE_ONCE(v->counter, i);
39}
40
41/**
42 * atomic_add - add integer to atomic variable
43 * @i: integer value to add
44 * @v: pointer of type atomic_t
45 *
46 * Atomically adds @i to @v.
47 */
48static __always_inline void atomic_add(int i, atomic_t *v)
49{
50 asm volatile(LOCK_PREFIX "addl %1,%0"
51 : "+m" (v->counter)
52 : "ir" (i));
53}
54
55/**
56 * atomic_sub - subtract integer from atomic variable
57 * @i: integer value to subtract
58 * @v: pointer of type atomic_t
59 *
60 * Atomically subtracts @i from @v.
61 */
62static __always_inline void atomic_sub(int i, atomic_t *v)
63{
64 asm volatile(LOCK_PREFIX "subl %1,%0"
65 : "+m" (v->counter)
66 : "ir" (i));
67}
68
69/**
70 * atomic_sub_and_test - subtract value from variable and test result
71 * @i: integer value to subtract
72 * @v: pointer of type atomic_t
73 *
74 * Atomically subtracts @i from @v and returns
75 * true if the result is zero, or false for all
76 * other cases.
77 */
78static __always_inline bool atomic_sub_and_test(int i, atomic_t *v)
79{
80 GEN_BINARY_RMWcc(LOCK_PREFIX "subl", v->counter, "er", i, "%0", e);
81}
82
83/**
84 * atomic_inc - increment atomic variable
85 * @v: pointer of type atomic_t
86 *
87 * Atomically increments @v by 1.
88 */
89static __always_inline void atomic_inc(atomic_t *v)
90{
91 asm volatile(LOCK_PREFIX "incl %0"
92 : "+m" (v->counter));
93}
94
95/**
96 * atomic_dec - decrement atomic variable
97 * @v: pointer of type atomic_t
98 *
99 * Atomically decrements @v by 1.
100 */
101static __always_inline void atomic_dec(atomic_t *v)
102{
103 asm volatile(LOCK_PREFIX "decl %0"
104 : "+m" (v->counter));
105}
106
107/**
108 * atomic_dec_and_test - decrement and test
109 * @v: pointer of type atomic_t
110 *
111 * Atomically decrements @v by 1 and
112 * returns true if the result is 0, or false for all other
113 * cases.
114 */
115static __always_inline bool atomic_dec_and_test(atomic_t *v)
116{
117 GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, "%0", e);
118}
119
120/**
121 * atomic_inc_and_test - increment and test
122 * @v: pointer of type atomic_t
123 *
124 * Atomically increments @v by 1
125 * and returns true if the result is zero, or false for all
126 * other cases.
127 */
128static __always_inline bool atomic_inc_and_test(atomic_t *v)
129{
130 GEN_UNARY_RMWcc(LOCK_PREFIX "incl", v->counter, "%0", e);
131}
132
133/**
134 * atomic_add_negative - add and test if negative
135 * @i: integer value to add
136 * @v: pointer of type atomic_t
137 *
138 * Atomically adds @i to @v and returns true
139 * if the result is negative, or false when
140 * result is greater than or equal to zero.
141 */
142static __always_inline bool atomic_add_negative(int i, atomic_t *v)
143{
144 GEN_BINARY_RMWcc(LOCK_PREFIX "addl", v->counter, "er", i, "%0", s);
145}
146
147/**
148 * atomic_add_return - add integer and return
149 * @i: integer value to add
150 * @v: pointer of type atomic_t
151 *
152 * Atomically adds @i to @v and returns @i + @v
153 */
154static __always_inline int atomic_add_return(int i, atomic_t *v)
155{
156 return i + xadd(&v->counter, i);
157}
158
159/**
160 * atomic_sub_return - subtract integer and return
161 * @v: pointer of type atomic_t
162 * @i: integer value to subtract
163 *
164 * Atomically subtracts @i from @v and returns @v - @i
165 */
166static __always_inline int atomic_sub_return(int i, atomic_t *v)
167{
168 return atomic_add_return(-i, v);
169}
170
171#define atomic_inc_return(v) (atomic_add_return(1, v))
172#define atomic_dec_return(v) (atomic_sub_return(1, v))
173
174static __always_inline int atomic_fetch_add(int i, atomic_t *v)
175{
176 return xadd(&v->counter, i);
177}
178
179static __always_inline int atomic_fetch_sub(int i, atomic_t *v)
180{
181 return xadd(&v->counter, -i);
182}
183
184static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new)
185{
186 return cmpxchg(&v->counter, old, new);
187}
188
189static inline int atomic_xchg(atomic_t *v, int new)
190{
191 return xchg(&v->counter, new);
192}
193
194#define ATOMIC_OP(op) \
195static inline void atomic_##op(int i, atomic_t *v) \
196{ \
197 asm volatile(LOCK_PREFIX #op"l %1,%0" \
198 : "+m" (v->counter) \
199 : "ir" (i) \
200 : "memory"); \
201}
202
203#define ATOMIC_FETCH_OP(op, c_op) \
204static inline int atomic_fetch_##op(int i, atomic_t *v) \
205{ \
206 int old, val = atomic_read(v); \
207 for (;;) { \
208 old = atomic_cmpxchg(v, val, val c_op i); \
209 if (old == val) \
210 break; \
211 val = old; \
212 } \
213 return old; \
214}
215
216#define ATOMIC_OPS(op, c_op) \
217 ATOMIC_OP(op) \
218 ATOMIC_FETCH_OP(op, c_op)
219
220ATOMIC_OPS(and, &)
221ATOMIC_OPS(or , |)
222ATOMIC_OPS(xor, ^)
223
224#undef ATOMIC_OPS
225#undef ATOMIC_FETCH_OP
226#undef ATOMIC_OP
227
228/**
229 * __atomic_add_unless - add unless the number is already a given value
230 * @v: pointer of type atomic_t
231 * @a: the amount to add to v...
232 * @u: ...unless v is equal to u.
233 *
234 * Atomically adds @a to @v, so long as @v was not already @u.
235 * Returns the old value of @v.
236 */
237static __always_inline int __atomic_add_unless(atomic_t *v, int a, int u)
238{
239 int c, old;
240 c = atomic_read(v);
241 for (;;) {
242 if (unlikely(c == (u)))
243 break;
244 old = atomic_cmpxchg((v), c, c + (a));
245 if (likely(old == c))
246 break;
247 c = old;
248 }
249 return c;
250}
251
252/**
253 * atomic_inc_short - increment of a short integer
254 * @v: pointer to type int
255 *
256 * Atomically adds 1 to @v
257 * Returns the new value of @u
258 */
259static __always_inline short int atomic_inc_short(short int *v)
260{
261 asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v));
262 return *v;
263}
264
265#ifdef CONFIG_X86_32
266# include <asm/atomic64_32.h>
267#else
268# include <asm/atomic64_64.h>
269#endif
270
271#endif /* _ASM_X86_ATOMIC_H */
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_ATOMIC_H
3#define _ASM_X86_ATOMIC_H
4
5#include <linux/compiler.h>
6#include <linux/types.h>
7#include <asm/alternative.h>
8#include <asm/cmpxchg.h>
9#include <asm/rmwcc.h>
10#include <asm/barrier.h>
11
12/*
13 * Atomic operations that C can't guarantee us. Useful for
14 * resource counting etc..
15 */
16
17/**
18 * arch_atomic_read - read atomic variable
19 * @v: pointer of type atomic_t
20 *
21 * Atomically reads the value of @v.
22 */
23static __always_inline int arch_atomic_read(const atomic_t *v)
24{
25 /*
26 * Note for KASAN: we deliberately don't use READ_ONCE_NOCHECK() here,
27 * it's non-inlined function that increases binary size and stack usage.
28 */
29 return __READ_ONCE((v)->counter);
30}
31
32/**
33 * arch_atomic_set - set atomic variable
34 * @v: pointer of type atomic_t
35 * @i: required value
36 *
37 * Atomically sets the value of @v to @i.
38 */
39static __always_inline void arch_atomic_set(atomic_t *v, int i)
40{
41 __WRITE_ONCE(v->counter, i);
42}
43
44/**
45 * arch_atomic_add - add integer to atomic variable
46 * @i: integer value to add
47 * @v: pointer of type atomic_t
48 *
49 * Atomically adds @i to @v.
50 */
51static __always_inline void arch_atomic_add(int i, atomic_t *v)
52{
53 asm volatile(LOCK_PREFIX "addl %1,%0"
54 : "+m" (v->counter)
55 : "ir" (i) : "memory");
56}
57
58/**
59 * arch_atomic_sub - subtract integer from atomic variable
60 * @i: integer value to subtract
61 * @v: pointer of type atomic_t
62 *
63 * Atomically subtracts @i from @v.
64 */
65static __always_inline void arch_atomic_sub(int i, atomic_t *v)
66{
67 asm volatile(LOCK_PREFIX "subl %1,%0"
68 : "+m" (v->counter)
69 : "ir" (i) : "memory");
70}
71
72/**
73 * arch_atomic_sub_and_test - subtract value from variable and test result
74 * @i: integer value to subtract
75 * @v: pointer of type atomic_t
76 *
77 * Atomically subtracts @i from @v and returns
78 * true if the result is zero, or false for all
79 * other cases.
80 */
81static __always_inline bool arch_atomic_sub_and_test(int i, atomic_t *v)
82{
83 return GEN_BINARY_RMWcc(LOCK_PREFIX "subl", v->counter, e, "er", i);
84}
85#define arch_atomic_sub_and_test arch_atomic_sub_and_test
86
87/**
88 * arch_atomic_inc - increment atomic variable
89 * @v: pointer of type atomic_t
90 *
91 * Atomically increments @v by 1.
92 */
93static __always_inline void arch_atomic_inc(atomic_t *v)
94{
95 asm volatile(LOCK_PREFIX "incl %0"
96 : "+m" (v->counter) :: "memory");
97}
98#define arch_atomic_inc arch_atomic_inc
99
100/**
101 * arch_atomic_dec - decrement atomic variable
102 * @v: pointer of type atomic_t
103 *
104 * Atomically decrements @v by 1.
105 */
106static __always_inline void arch_atomic_dec(atomic_t *v)
107{
108 asm volatile(LOCK_PREFIX "decl %0"
109 : "+m" (v->counter) :: "memory");
110}
111#define arch_atomic_dec arch_atomic_dec
112
113/**
114 * arch_atomic_dec_and_test - decrement and test
115 * @v: pointer of type atomic_t
116 *
117 * Atomically decrements @v by 1 and
118 * returns true if the result is 0, or false for all other
119 * cases.
120 */
121static __always_inline bool arch_atomic_dec_and_test(atomic_t *v)
122{
123 return GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, e);
124}
125#define arch_atomic_dec_and_test arch_atomic_dec_and_test
126
127/**
128 * arch_atomic_inc_and_test - increment and test
129 * @v: pointer of type atomic_t
130 *
131 * Atomically increments @v by 1
132 * and returns true if the result is zero, or false for all
133 * other cases.
134 */
135static __always_inline bool arch_atomic_inc_and_test(atomic_t *v)
136{
137 return GEN_UNARY_RMWcc(LOCK_PREFIX "incl", v->counter, e);
138}
139#define arch_atomic_inc_and_test arch_atomic_inc_and_test
140
141/**
142 * arch_atomic_add_negative - add and test if negative
143 * @i: integer value to add
144 * @v: pointer of type atomic_t
145 *
146 * Atomically adds @i to @v and returns true
147 * if the result is negative, or false when
148 * result is greater than or equal to zero.
149 */
150static __always_inline bool arch_atomic_add_negative(int i, atomic_t *v)
151{
152 return GEN_BINARY_RMWcc(LOCK_PREFIX "addl", v->counter, s, "er", i);
153}
154#define arch_atomic_add_negative arch_atomic_add_negative
155
156/**
157 * arch_atomic_add_return - add integer and return
158 * @i: integer value to add
159 * @v: pointer of type atomic_t
160 *
161 * Atomically adds @i to @v and returns @i + @v
162 */
163static __always_inline int arch_atomic_add_return(int i, atomic_t *v)
164{
165 return i + xadd(&v->counter, i);
166}
167#define arch_atomic_add_return arch_atomic_add_return
168
169/**
170 * arch_atomic_sub_return - subtract integer and return
171 * @v: pointer of type atomic_t
172 * @i: integer value to subtract
173 *
174 * Atomically subtracts @i from @v and returns @v - @i
175 */
176static __always_inline int arch_atomic_sub_return(int i, atomic_t *v)
177{
178 return arch_atomic_add_return(-i, v);
179}
180#define arch_atomic_sub_return arch_atomic_sub_return
181
182static __always_inline int arch_atomic_fetch_add(int i, atomic_t *v)
183{
184 return xadd(&v->counter, i);
185}
186#define arch_atomic_fetch_add arch_atomic_fetch_add
187
188static __always_inline int arch_atomic_fetch_sub(int i, atomic_t *v)
189{
190 return xadd(&v->counter, -i);
191}
192#define arch_atomic_fetch_sub arch_atomic_fetch_sub
193
194static __always_inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
195{
196 return arch_cmpxchg(&v->counter, old, new);
197}
198#define arch_atomic_cmpxchg arch_atomic_cmpxchg
199
200static __always_inline bool arch_atomic_try_cmpxchg(atomic_t *v, int *old, int new)
201{
202 return arch_try_cmpxchg(&v->counter, old, new);
203}
204#define arch_atomic_try_cmpxchg arch_atomic_try_cmpxchg
205
206static __always_inline int arch_atomic_xchg(atomic_t *v, int new)
207{
208 return arch_xchg(&v->counter, new);
209}
210#define arch_atomic_xchg arch_atomic_xchg
211
212static __always_inline void arch_atomic_and(int i, atomic_t *v)
213{
214 asm volatile(LOCK_PREFIX "andl %1,%0"
215 : "+m" (v->counter)
216 : "ir" (i)
217 : "memory");
218}
219
220static __always_inline int arch_atomic_fetch_and(int i, atomic_t *v)
221{
222 int val = arch_atomic_read(v);
223
224 do { } while (!arch_atomic_try_cmpxchg(v, &val, val & i));
225
226 return val;
227}
228#define arch_atomic_fetch_and arch_atomic_fetch_and
229
230static __always_inline void arch_atomic_or(int i, atomic_t *v)
231{
232 asm volatile(LOCK_PREFIX "orl %1,%0"
233 : "+m" (v->counter)
234 : "ir" (i)
235 : "memory");
236}
237
238static __always_inline int arch_atomic_fetch_or(int i, atomic_t *v)
239{
240 int val = arch_atomic_read(v);
241
242 do { } while (!arch_atomic_try_cmpxchg(v, &val, val | i));
243
244 return val;
245}
246#define arch_atomic_fetch_or arch_atomic_fetch_or
247
248static __always_inline void arch_atomic_xor(int i, atomic_t *v)
249{
250 asm volatile(LOCK_PREFIX "xorl %1,%0"
251 : "+m" (v->counter)
252 : "ir" (i)
253 : "memory");
254}
255
256static __always_inline int arch_atomic_fetch_xor(int i, atomic_t *v)
257{
258 int val = arch_atomic_read(v);
259
260 do { } while (!arch_atomic_try_cmpxchg(v, &val, val ^ i));
261
262 return val;
263}
264#define arch_atomic_fetch_xor arch_atomic_fetch_xor
265
266#ifdef CONFIG_X86_32
267# include <asm/atomic64_32.h>
268#else
269# include <asm/atomic64_64.h>
270#endif
271
272#endif /* _ASM_X86_ATOMIC_H */