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 */
28extern 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 */
69extern 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)						\
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 /* _ASM_IA64_CMPXCHG_H */
156