1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _TOOLS_LINUX_ASM_X86_ATOMIC_H
3 #define _TOOLS_LINUX_ASM_X86_ATOMIC_H
4
5 #include <linux/compiler.h>
6 #include <linux/types.h>
7 #include "rmwcc.h"
8
9 #define LOCK_PREFIX "\n\tlock; "
10
11 #include <asm/asm.h>
12 #include <asm/cmpxchg.h>
13
14 /*
15 * Atomic operations that C can't guarantee us. Useful for
16 * resource counting etc..
17 */
18
19 #define ATOMIC_INIT(i) { (i) }
20
21 /**
22 * atomic_read - read atomic variable
23 * @v: pointer of type atomic_t
24 *
25 * Atomically reads the value of @v.
26 */
27 static inline int atomic_read(const atomic_t *v)
28 {
29 return READ_ONCE((v)->counter);
30 }
31
32 /**
33 * 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 */
39 static inline void atomic_set(atomic_t *v, int i)
40 {
41 v->counter = i;
42 }
43
44 /**
45 * atomic_inc - increment atomic variable
46 * @v: pointer of type atomic_t
47 *
48 * Atomically increments @v by 1.
49 */
50 static inline void atomic_inc(atomic_t *v)
51 {
52 asm volatile(LOCK_PREFIX "incl %0"
53 : "+m" (v->counter));
54 }
55
56 /**
57 * atomic_dec_and_test - decrement and test
58 * @v: pointer of type atomic_t
59 *
60 * Atomically decrements @v by 1 and
61 * returns true if the result is 0, or false for all other
62 * cases.
63 */
64 static inline int atomic_dec_and_test(atomic_t *v)
65 {
66 GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, "%0", "e");
67 }
68
69 static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new)
70 {
71 return cmpxchg(&v->counter, old, new);
72 }
73
74 static inline int test_and_set_bit(long nr, unsigned long *addr)
75 {
76 GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, "Ir", nr, "%0", "c");
77 }
78
79 static inline int test_and_clear_bit(long nr, unsigned long *addr)
80 {
81 GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc), *addr, "Ir", nr, "%0", "c");
82 }
83
84 #endif /* _TOOLS_LINUX_ASM_X86_ATOMIC_H */
85
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