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Ralf Baechlefef74702007-10-01 04:15:00 +01001/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2003, 06, 07 by Ralf Baechle (ralf@linux-mips.org)
7 */
8#ifndef __ASM_CMPXCHG_H
9#define __ASM_CMPXCHG_H
10
11#include <linux/irqflags.h>
12
13#define __HAVE_ARCH_CMPXCHG 1
14
15#define __cmpxchg_asm(ld, st, m, old, new) \
16({ \
17 __typeof(*(m)) __ret; \
18 \
19 if (cpu_has_llsc && R10000_LLSC_WAR) { \
20 __asm__ __volatile__( \
21 " .set push \n" \
22 " .set noat \n" \
23 " .set mips3 \n" \
24 "1: " ld " %0, %2 # __cmpxchg_asm \n" \
25 " bne %0, %z3, 2f \n" \
26 " .set mips0 \n" \
27 " move $1, %z4 \n" \
28 " .set mips3 \n" \
29 " " st " $1, %1 \n" \
30 " beqzl $1, 1b \n" \
31 "2: \n" \
32 " .set pop \n" \
33 : "=&r" (__ret), "=R" (*m) \
34 : "R" (*m), "Jr" (old), "Jr" (new) \
35 : "memory"); \
36 } else if (cpu_has_llsc) { \
37 __asm__ __volatile__( \
38 " .set push \n" \
39 " .set noat \n" \
40 " .set mips3 \n" \
41 "1: " ld " %0, %2 # __cmpxchg_asm \n" \
42 " bne %0, %z3, 2f \n" \
43 " .set mips0 \n" \
44 " move $1, %z4 \n" \
45 " .set mips3 \n" \
46 " " st " $1, %1 \n" \
47 " beqz $1, 3f \n" \
48 "2: \n" \
49 " .subsection 2 \n" \
50 "3: b 1b \n" \
51 " .previous \n" \
52 " .set pop \n" \
53 : "=&r" (__ret), "=R" (*m) \
54 : "R" (*m), "Jr" (old), "Jr" (new) \
55 : "memory"); \
56 } else { \
57 unsigned long __flags; \
58 \
59 raw_local_irq_save(__flags); \
60 __ret = *m; \
61 if (__ret == old) \
62 *m = new; \
63 raw_local_irq_restore(__flags); \
64 } \
65 \
66 __ret; \
67})
68
69/*
70 * This function doesn't exist, so you'll get a linker error
71 * if something tries to do an invalid cmpxchg().
72 */
73extern void __cmpxchg_called_with_bad_pointer(void);
74
Ralf Baechle21a151d2007-10-11 23:46:15 +010075#define __cmpxchg(ptr, old, new, barrier) \
Ralf Baechlefef74702007-10-01 04:15:00 +010076({ \
77 __typeof__(ptr) __ptr = (ptr); \
78 __typeof__(*(ptr)) __old = (old); \
79 __typeof__(*(ptr)) __new = (new); \
80 __typeof__(*(ptr)) __res = 0; \
81 \
82 barrier; \
83 \
84 switch (sizeof(*(__ptr))) { \
85 case 4: \
86 __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
87 break; \
88 case 8: \
89 if (sizeof(long) == 8) { \
90 __res = __cmpxchg_asm("lld", "scd", __ptr, \
91 __old, __new); \
92 break; \
93 } \
94 default: \
95 __cmpxchg_called_with_bad_pointer(); \
96 break; \
97 } \
98 \
99 barrier; \
100 \
101 __res; \
102})
103
104#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_llsc_mb())
Ralf Baechle21a151d2007-10-11 23:46:15 +0100105#define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, )
Ralf Baechlefef74702007-10-01 04:15:00 +0100106
107#endif /* __ASM_CMPXCHG_H */