1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_CMPXCHG_64_H
3#define _ASM_X86_CMPXCHG_64_H
4
5#define arch_cmpxchg64(ptr, o, n) \
6({ \
7 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
8 arch_cmpxchg((ptr), (o), (n)); \
9})
10
11#define arch_cmpxchg64_local(ptr, o, n) \
12({ \
13 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
14 arch_cmpxchg_local((ptr), (o), (n)); \
15})
16
17#define arch_try_cmpxchg64(ptr, po, n) \
18({ \
19 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
20 arch_try_cmpxchg((ptr), (po), (n)); \
21})
22
23#define arch_try_cmpxchg64_local(ptr, po, n) \
24({ \
25 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
26 arch_try_cmpxchg_local((ptr), (po), (n)); \
27})
28
29union __u128_halves {
30 u128 full;
31 struct {
32 u64 low, high;
33 };
34};
35
36#define __arch_cmpxchg128(_ptr, _old, _new, _lock) \
37({ \
38 union __u128_halves o = { .full = (_old), }, \
39 n = { .full = (_new), }; \
40 \
41 asm_inline volatile(_lock "cmpxchg16b %[ptr]" \
42 : [ptr] "+m" (*(_ptr)), \
43 "+a" (o.low), "+d" (o.high) \
44 : "b" (n.low), "c" (n.high) \
45 : "memory"); \
46 \
47 o.full; \
48})
49
50static __always_inline u128 arch_cmpxchg128(volatile u128 *ptr, u128 old, u128 new)
51{
52 return __arch_cmpxchg128(ptr, old, new, LOCK_PREFIX);
53}
54#define arch_cmpxchg128 arch_cmpxchg128
55
56static __always_inline u128 arch_cmpxchg128_local(volatile u128 *ptr, u128 old, u128 new)
57{
58 return __arch_cmpxchg128(ptr, old, new,);
59}
60#define arch_cmpxchg128_local arch_cmpxchg128_local
61
62#define __arch_try_cmpxchg128(_ptr, _oldp, _new, _lock) \
63({ \
64 union __u128_halves o = { .full = *(_oldp), }, \
65 n = { .full = (_new), }; \
66 bool ret; \
67 \
68 asm_inline volatile(_lock "cmpxchg16b %[ptr]" \
69 CC_SET(e) \
70 : CC_OUT(e) (ret), \
71 [ptr] "+m" (*(_ptr)), \
72 "+a" (o.low), "+d" (o.high) \
73 : "b" (n.low), "c" (n.high) \
74 : "memory"); \
75 \
76 if (unlikely(!ret)) \
77 *(_oldp) = o.full; \
78 \
79 likely(ret); \
80})
81
82static __always_inline bool arch_try_cmpxchg128(volatile u128 *ptr, u128 *oldp, u128 new)
83{
84 return __arch_try_cmpxchg128(ptr, oldp, new, LOCK_PREFIX);
85}
86#define arch_try_cmpxchg128 arch_try_cmpxchg128
87
88static __always_inline bool arch_try_cmpxchg128_local(volatile u128 *ptr, u128 *oldp, u128 new)
89{
90 return __arch_try_cmpxchg128(ptr, oldp, new,);
91}
92#define arch_try_cmpxchg128_local arch_try_cmpxchg128_local
93
94#define system_has_cmpxchg128() boot_cpu_has(X86_FEATURE_CX16)
95
96#endif /* _ASM_X86_CMPXCHG_64_H */
97

source code of linux/arch/x86/include/asm/cmpxchg_64.h