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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _UAPI_ASM_IA64_CMPXCHG_H
3#define _UAPI_ASM_IA64_CMPXCHG_H
4
5/*
6 * Compare/Exchange, forked from asm/intrinsics.h
7 * which was:
8 *
9 * Copyright (C) 2002-2003 Hewlett-Packard Co
10 * David Mosberger-Tang <davidm@hpl.hp.com>
11 */
12
13#ifndef __ASSEMBLY__
14
15#include <linux/types.h>
16/* include compiler specific intrinsics */
17#include <asm/ia64regs.h>
18#include <asm/gcc_intrin.h>
19
20/*
21 * This function doesn't exist, so you'll get a linker error if
22 * something tries to do an invalid xchg().
23 */
24extern void ia64_xchg_called_with_bad_pointer(void);
25
26#define __xchg(x, ptr, size) \
27({ \
28 unsigned long __xchg_result; \
29 \
30 switch (size) { \
31 case 1: \
32 __xchg_result = ia64_xchg1((__u8 __force *)ptr, x); \
33 break; \
34 \
35 case 2: \
36 __xchg_result = ia64_xchg2((__u16 __force *)ptr, x); \
37 break; \
38 \
39 case 4: \
40 __xchg_result = ia64_xchg4((__u32 __force *)ptr, x); \
41 break; \
42 \
43 case 8: \
44 __xchg_result = ia64_xchg8((__u64 __force *)ptr, x); \
45 break; \
46 default: \
47 ia64_xchg_called_with_bad_pointer(); \
48 } \
49 (__typeof__ (*(ptr)) __force) __xchg_result; \
50})
51
52#ifndef __KERNEL__
53#define xchg(ptr, x) \
54({(__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr)));})
55#endif
56
57/*
58 * Atomic compare and exchange. Compare OLD with MEM, if identical,
59 * store NEW in MEM. Return the initial value in MEM. Success is
60 * indicated by comparing RETURN with OLD.
61 */
62
63/*
64 * This function doesn't exist, so you'll get a linker error
65 * if something tries to do an invalid cmpxchg().
66 */
67extern long ia64_cmpxchg_called_with_bad_pointer(void);
68
69#define ia64_cmpxchg(sem, ptr, old, new, size) \
70({ \
71 __u64 _o_, _r_; \
72 \
73 switch (size) { \
74 case 1: \
75 _o_ = (__u8) (long __force) (old); \
76 break; \
77 case 2: \
78 _o_ = (__u16) (long __force) (old); \
79 break; \
80 case 4: \
81 _o_ = (__u32) (long __force) (old); \
82 break; \
83 case 8: \
84 _o_ = (__u64) (long __force) (old); \
85 break; \
86 default: \
87 break; \
88 } \
89 switch (size) { \
90 case 1: \
91 _r_ = ia64_cmpxchg1_##sem((__u8 __force *) ptr, new, _o_); \
92 break; \
93 \
94 case 2: \
95 _r_ = ia64_cmpxchg2_##sem((__u16 __force *) ptr, new, _o_); \
96 break; \
97 \
98 case 4: \
99 _r_ = ia64_cmpxchg4_##sem((__u32 __force *) ptr, new, _o_); \
100 break; \
101 \
102 case 8: \
103 _r_ = ia64_cmpxchg8_##sem((__u64 __force *) ptr, new, _o_); \
104 break; \
105 \
106 default: \
107 _r_ = ia64_cmpxchg_called_with_bad_pointer(); \
108 break; \
109 } \
110 (__typeof__(old) __force) _r_; \
111})
112
113#define cmpxchg_acq(ptr, o, n) \
114 ia64_cmpxchg(acq, (ptr), (o), (n), sizeof(*(ptr)))
115#define cmpxchg_rel(ptr, o, n) \
116 ia64_cmpxchg(rel, (ptr), (o), (n), sizeof(*(ptr)))
117
118/*
119 * Worse still - early processor implementations actually just ignored
120 * the acquire/release and did a full fence all the time. Unfortunately
121 * this meant a lot of badly written code that used .acq when they really
122 * wanted .rel became legacy out in the wild - so when we made a cpu
123 * that strictly did the .acq or .rel ... all that code started breaking - so
124 * we had to back-pedal and keep the "legacy" behavior of a full fence :-(
125 */
126
127#ifndef __KERNEL__
128/* for compatibility with other platforms: */
129#define cmpxchg(ptr, o, n) cmpxchg_acq((ptr), (o), (n))
130#define cmpxchg64(ptr, o, n) cmpxchg_acq((ptr), (o), (n))
131
132#define cmpxchg_local cmpxchg
133#define cmpxchg64_local cmpxchg64
134#endif
135
136#ifdef CONFIG_IA64_DEBUG_CMPXCHG
137# define CMPXCHG_BUGCHECK_DECL int _cmpxchg_bugcheck_count = 128;
138# define CMPXCHG_BUGCHECK(v) \
139do { \
140 if (_cmpxchg_bugcheck_count-- <= 0) { \
141 void *ip; \
142 extern int _printk(const char *fmt, ...); \
143 ip = (void *) ia64_getreg(_IA64_REG_IP); \
144 _printk("CMPXCHG_BUGCHECK: stuck at %p on word %p\n", ip, (v));\
145 break; \
146 } \
147} while (0)
148#else /* !CONFIG_IA64_DEBUG_CMPXCHG */
149# define CMPXCHG_BUGCHECK_DECL
150# define CMPXCHG_BUGCHECK(v)
151#endif /* !CONFIG_IA64_DEBUG_CMPXCHG */
152
153#endif /* !__ASSEMBLY__ */
154
155#endif /* _UAPI_ASM_IA64_CMPXCHG_H */