1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _ASM_IA64_CMPXCHG_H
3 #define _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 #ifdef __INTEL_COMPILER
19 # include <asm/intel_intrin.h>
20 #else
21 # include <asm/gcc_intrin.h>
22 #endif
23
24 /*
25 * This function doesn't exist, so you'll get a linker error if
26 * something tries to do an invalid xchg().
27 */
28 extern void ia64_xchg_called_with_bad_pointer(void);
29
30 #define __xchg(x, ptr, size) \
31 ({ \
32 unsigned long __xchg_result; \
33 \
34 switch (size) { \
35 case 1: \
36 __xchg_result = ia64_xchg1((__u8 *)ptr, x); \
37 break; \
38 \
39 case 2: \
40 __xchg_result = ia64_xchg2((__u16 *)ptr, x); \
41 break; \
42 \
43 case 4: \
44 __xchg_result = ia64_xchg4((__u32 *)ptr, x); \
45 break; \
46 \
47 case 8: \
48 __xchg_result = ia64_xchg8((__u64 *)ptr, x); \
49 break; \
50 default: \
51 ia64_xchg_called_with_bad_pointer(); \
52 } \
53 __xchg_result; \
54 })
55
56 #define xchg(ptr, x) \
57 ((__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr))))
58
59 /*
60 * Atomic compare and exchange. Compare OLD with MEM, if identical,
61 * store NEW in MEM. Return the initial value in MEM. Success is
62 * indicated by comparing RETURN with OLD.
63 */
64
65 /*
66 * This function doesn't exist, so you'll get a linker error
67 * if something tries to do an invalid cmpxchg().
68 */
69 extern long ia64_cmpxchg_called_with_bad_pointer(void);
70
71 #define ia64_cmpxchg(sem, ptr, old, new, size) \
72 ({ \
73 __u64 _o_, _r_; \
74 \
75 switch (size) { \
76 case 1: \
77 _o_ = (__u8) (long) (old); \
78 break; \
79 case 2: \
80 _o_ = (__u16) (long) (old); \
81 break; \
82 case 4: \
83 _o_ = (__u32) (long) (old); \
84 break; \
85 case 8: \
86 _o_ = (__u64) (long) (old); \
87 break; \
88 default: \
89 break; \
90 } \
91 switch (size) { \
92 case 1: \
93 _r_ = ia64_cmpxchg1_##sem((__u8 *) ptr, new, _o_); \
94 break; \
95 \
96 case 2: \
97 _r_ = ia64_cmpxchg2_##sem((__u16 *) ptr, new, _o_); \
98 break; \
99 \
100 case 4: \
101 _r_ = ia64_cmpxchg4_##sem((__u32 *) ptr, new, _o_); \
102 break; \
103 \
104 case 8: \
105 _r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_); \
106 break; \
107 \
108 default: \
109 _r_ = ia64_cmpxchg_called_with_bad_pointer(); \
110 break; \
111 } \
112 (__typeof__(old)) _r_; \
113 })
114
115 #define cmpxchg_acq(ptr, o, n) \
116 ia64_cmpxchg(acq, (ptr), (o), (n), sizeof(*(ptr)))
117 #define cmpxchg_rel(ptr, o, n) \
118 ia64_cmpxchg(rel, (ptr), (o), (n), sizeof(*(ptr)))
119
120 /*
121 * Worse still - early processor implementations actually just ignored
122 * the acquire/release and did a full fence all the time. Unfortunately
123 * this meant a lot of badly written code that used .acq when they really
124 * wanted .rel became legacy out in the wild - so when we made a cpu
125 * that strictly did the .acq or .rel ... all that code started breaking - so
126 * we had to back-pedal and keep the "legacy" behavior of a full fence :-(
127 */
128
129 /* for compatibility with other platforms: */
130 #define cmpxchg(ptr, o, n) cmpxchg_acq((ptr), (o), (n))
131 #define cmpxchg64(ptr, o, n) cmpxchg_acq((ptr), (o), (n))
132
133 #define cmpxchg_local cmpxchg
134 #define cmpxchg64_local cmpxchg64
135
136 #ifdef CONFIG_IA64_DEBUG_CMPXCHG
137 # define CMPXCHG_BUGCHECK_DECL int _cmpxchg_bugcheck_count = 128;
138 # define CMPXCHG_BUGCHECK(v) \
139 do { \
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 /* _ASM_IA64_CMPXCHG_H */