cmpxchg_64.h

 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		     : "=@ccz" (ret),					\
70		       [ptr] "+m" (*(_ptr)),				\
71		       "+a" (o.low), "+d" (o.high)			\
72		     : "b" (n.low), "c" (n.high)			\
73		     : "memory");					\
74									\
75	if (unlikely(!ret))						\
76		*(_oldp) = o.full;					\
77									\
78	likely(ret);							\
79})
80
81static __always_inline bool arch_try_cmpxchg128(volatile u128 *ptr, u128 *oldp, u128 new)
82{
83	return __arch_try_cmpxchg128(ptr, oldp, new, LOCK_PREFIX);
84}
85#define arch_try_cmpxchg128 arch_try_cmpxchg128
86
87static __always_inline bool arch_try_cmpxchg128_local(volatile u128 *ptr, u128 *oldp, u128 new)
88{
89	return __arch_try_cmpxchg128(ptr, oldp, new,);
90}
91#define arch_try_cmpxchg128_local arch_try_cmpxchg128_local
92
93#define system_has_cmpxchg128()		boot_cpu_has(X86_FEATURE_CX16)
94
95#endif /* _ASM_X86_CMPXCHG_64_H */