1 /* 64-bit atomic xchg() and cmpxchg() definitions.
2 *
3 * Copyright (C) 1996, 1997, 2000 David S. Miller (davem@redhat.com)
4 */
5
6 #ifndef __ARCH_SPARC64_CMPXCHG__
7 #define __ARCH_SPARC64_CMPXCHG__
8
xchg32(__volatile__ unsigned int * m,unsigned int val)9 static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int val)
10 {
11 unsigned long tmp1, tmp2;
12
13 __asm__ __volatile__(
14 " mov %0, %1\n"
15 "1: lduw [%4], %2\n"
16 " cas [%4], %2, %0\n"
17 " cmp %2, %0\n"
18 " bne,a,pn %%icc, 1b\n"
19 " mov %1, %0\n"
20 : "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
21 : "0" (val), "r" (m)
22 : "cc", "memory");
23 return val;
24 }
25
xchg64(__volatile__ unsigned long * m,unsigned long val)26 static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long val)
27 {
28 unsigned long tmp1, tmp2;
29
30 __asm__ __volatile__(
31 " mov %0, %1\n"
32 "1: ldx [%4], %2\n"
33 " casx [%4], %2, %0\n"
34 " cmp %2, %0\n"
35 " bne,a,pn %%xcc, 1b\n"
36 " mov %1, %0\n"
37 : "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
38 : "0" (val), "r" (m)
39 : "cc", "memory");
40 return val;
41 }
42
43 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
44
45 extern void __xchg_called_with_bad_pointer(void);
46
__xchg(unsigned long x,__volatile__ void * ptr,int size)47 static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
48 int size)
49 {
50 switch (size) {
51 case 4:
52 return xchg32(ptr, x);
53 case 8:
54 return xchg64(ptr, x);
55 }
56 __xchg_called_with_bad_pointer();
57 return x;
58 }
59
60 /*
61 * Atomic compare and exchange. Compare OLD with MEM, if identical,
62 * store NEW in MEM. Return the initial value in MEM. Success is
63 * indicated by comparing RETURN with OLD.
64 */
65
66 #include <asm-generic/cmpxchg-local.h>
67
68 #define __HAVE_ARCH_CMPXCHG 1
69
70 static inline unsigned long
__cmpxchg_u32(volatile int * m,int old,int new)71 __cmpxchg_u32(volatile int *m, int old, int new)
72 {
73 __asm__ __volatile__("cas [%2], %3, %0"
74 : "=&r" (new)
75 : "0" (new), "r" (m), "r" (old)
76 : "memory");
77
78 return new;
79 }
80
81 static inline unsigned long
__cmpxchg_u64(volatile long * m,unsigned long old,unsigned long new)82 __cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
83 {
84 __asm__ __volatile__("casx [%2], %3, %0"
85 : "=&r" (new)
86 : "0" (new), "r" (m), "r" (old)
87 : "memory");
88
89 return new;
90 }
91
92 /* This function doesn't exist, so you'll get a linker error
93 if something tries to do an invalid cmpxchg(). */
94 extern void __cmpxchg_called_with_bad_pointer(void);
95
96 static inline unsigned long
__cmpxchg(volatile void * ptr,unsigned long old,unsigned long new,int size)97 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
98 {
99 switch (size) {
100 case 4:
101 return __cmpxchg_u32(ptr, old, new);
102 case 8:
103 return __cmpxchg_u64(ptr, old, new);
104 }
105 __cmpxchg_called_with_bad_pointer();
106 return old;
107 }
108
109 #define cmpxchg(ptr,o,n) \
110 ({ \
111 __typeof__(*(ptr)) _o_ = (o); \
112 __typeof__(*(ptr)) _n_ = (n); \
113 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
114 (unsigned long)_n_, sizeof(*(ptr))); \
115 })
116
117 /*
118 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
119 * them available.
120 */
121
__cmpxchg_local(volatile void * ptr,unsigned long old,unsigned long new,int size)122 static inline unsigned long __cmpxchg_local(volatile void *ptr,
123 unsigned long old,
124 unsigned long new, int size)
125 {
126 switch (size) {
127 case 4:
128 case 8: return __cmpxchg(ptr, old, new, size);
129 default:
130 return __cmpxchg_local_generic(ptr, old, new, size);
131 }
132
133 return old;
134 }
135
136 #define cmpxchg_local(ptr, o, n) \
137 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
138 (unsigned long)(n), sizeof(*(ptr))))
139 #define cmpxchg64_local(ptr, o, n) \
140 ({ \
141 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
142 cmpxchg_local((ptr), (o), (n)); \
143 })
144
145 #endif /* __ARCH_SPARC64_CMPXCHG__ */
146