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f9aa7e18 DH |
1 | /* |
2 | * Atomic xchg and cmpxchg operations. | |
3 | * | |
4 | * This file is subject to the terms and conditions of the GNU General Public | |
5 | * License. See the file "COPYING" in the main directory of this archive | |
6 | * for more details. | |
7 | * | |
8 | * Copyright (C) 2001 - 2005 Tensilica Inc. | |
9 | */ | |
10 | ||
11 | #ifndef _XTENSA_CMPXCHG_H | |
12 | #define _XTENSA_CMPXCHG_H | |
13 | ||
14 | #ifndef __ASSEMBLY__ | |
15 | ||
16 | #include <linux/stringify.h> | |
17 | ||
18 | /* | |
19 | * cmpxchg | |
20 | */ | |
21 | ||
22 | static inline unsigned long | |
23 | __cmpxchg_u32(volatile int *p, int old, int new) | |
24 | { | |
219b1e4c MF |
25 | #if XCHAL_HAVE_S32C1I |
26 | __asm__ __volatile__( | |
27 | " wsr %2, scompare1\n" | |
28 | " s32c1i %0, %1, 0\n" | |
29 | : "+a" (new) | |
30 | : "a" (p), "a" (old) | |
31 | : "memory" | |
32 | ); | |
33 | ||
34 | return new; | |
35 | #else | |
36 | __asm__ __volatile__( | |
37 | " rsil a15, "__stringify(LOCKLEVEL)"\n" | |
38 | " l32i %0, %1, 0\n" | |
39 | " bne %0, %2, 1f\n" | |
40 | " s32i %3, %1, 0\n" | |
41 | "1:\n" | |
42 | " wsr a15, ps\n" | |
43 | " rsync\n" | |
44 | : "=&a" (old) | |
45 | : "a" (p), "a" (old), "r" (new) | |
46 | : "a15", "memory"); | |
47 | return old; | |
48 | #endif | |
f9aa7e18 DH |
49 | } |
50 | /* This function doesn't exist, so you'll get a linker error | |
51 | * if something tries to do an invalid cmpxchg(). */ | |
52 | ||
53 | extern void __cmpxchg_called_with_bad_pointer(void); | |
54 | ||
55 | static __inline__ unsigned long | |
56 | __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) | |
57 | { | |
58 | switch (size) { | |
59 | case 4: return __cmpxchg_u32(ptr, old, new); | |
60 | default: __cmpxchg_called_with_bad_pointer(); | |
61 | return old; | |
62 | } | |
63 | } | |
64 | ||
65 | #define cmpxchg(ptr,o,n) \ | |
66 | ({ __typeof__(*(ptr)) _o_ = (o); \ | |
67 | __typeof__(*(ptr)) _n_ = (n); \ | |
68 | (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ | |
69 | (unsigned long)_n_, sizeof (*(ptr))); \ | |
70 | }) | |
71 | ||
72 | #include <asm-generic/cmpxchg-local.h> | |
73 | ||
74 | static inline unsigned long __cmpxchg_local(volatile void *ptr, | |
75 | unsigned long old, | |
76 | unsigned long new, int size) | |
77 | { | |
78 | switch (size) { | |
79 | case 4: | |
80 | return __cmpxchg_u32(ptr, old, new); | |
81 | default: | |
82 | return __cmpxchg_local_generic(ptr, old, new, size); | |
83 | } | |
84 | ||
85 | return old; | |
86 | } | |
87 | ||
88 | /* | |
89 | * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make | |
90 | * them available. | |
91 | */ | |
92 | #define cmpxchg_local(ptr, o, n) \ | |
93 | ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ | |
94 | (unsigned long)(n), sizeof(*(ptr)))) | |
95 | #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) | |
b5514786 | 96 | #define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n)) |
f9aa7e18 DH |
97 | |
98 | /* | |
99 | * xchg_u32 | |
100 | * | |
101 | * Note that a15 is used here because the register allocation | |
102 | * done by the compiler is not guaranteed and a window overflow | |
103 | * may not occur between the rsil and wsr instructions. By using | |
104 | * a15 in the rsil, the machine is guaranteed to be in a state | |
105 | * where no register reference will cause an overflow. | |
106 | */ | |
107 | ||
108 | static inline unsigned long xchg_u32(volatile int * m, unsigned long val) | |
109 | { | |
219b1e4c MF |
110 | #if XCHAL_HAVE_S32C1I |
111 | unsigned long tmp, result; | |
112 | __asm__ __volatile__( | |
113 | "1: l32i %1, %2, 0\n" | |
114 | " mov %0, %3\n" | |
115 | " wsr %1, scompare1\n" | |
116 | " s32c1i %0, %2, 0\n" | |
117 | " bne %0, %1, 1b\n" | |
118 | : "=&a" (result), "=&a" (tmp) | |
119 | : "a" (m), "a" (val) | |
120 | : "memory" | |
121 | ); | |
122 | return result; | |
123 | #else | |
124 | unsigned long tmp; | |
125 | __asm__ __volatile__( | |
126 | " rsil a15, "__stringify(LOCKLEVEL)"\n" | |
127 | " l32i %0, %1, 0\n" | |
128 | " s32i %2, %1, 0\n" | |
129 | " wsr a15, ps\n" | |
130 | " rsync\n" | |
131 | : "=&a" (tmp) | |
132 | : "a" (m), "a" (val) | |
133 | : "a15", "memory"); | |
134 | return tmp; | |
135 | #endif | |
f9aa7e18 DH |
136 | } |
137 | ||
c4c4594b CZ |
138 | #define xchg(ptr,x) \ |
139 | ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) | |
f9aa7e18 DH |
140 | |
141 | /* | |
142 | * This only works if the compiler isn't horribly bad at optimizing. | |
143 | * gcc-2.5.8 reportedly can't handle this, but I define that one to | |
144 | * be dead anyway. | |
145 | */ | |
146 | ||
147 | extern void __xchg_called_with_bad_pointer(void); | |
148 | ||
149 | static __inline__ unsigned long | |
150 | __xchg(unsigned long x, volatile void * ptr, int size) | |
151 | { | |
152 | switch (size) { | |
153 | case 4: | |
154 | return xchg_u32(ptr, x); | |
155 | } | |
156 | __xchg_called_with_bad_pointer(); | |
157 | return x; | |
158 | } | |
159 | ||
160 | #endif /* __ASSEMBLY__ */ | |
161 | ||
162 | #endif /* _XTENSA_CMPXCHG_H */ |