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8#ifndef __ASM_CMPXCHG_H
9#define __ASM_CMPXCHG_H
10
11#include <linux/bug.h>
12#include <linux/irqflags.h>
13#include <asm/compiler.h>
14#include <asm/war.h>
15
16static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
17{
18 __u32 retval;
19
20 smp_mb__before_llsc();
21
22 if (kernel_uses_llsc && R10000_LLSC_WAR) {
23 unsigned long dummy;
24
25 __asm__ __volatile__(
26 " .set arch=r4000 \n"
27 "1: ll %0, %3 # xchg_u32 \n"
28 " .set mips0 \n"
29 " move %2, %z4 \n"
30 " .set arch=r4000 \n"
31 " sc %2, %1 \n"
32 " beqzl %2, 1b \n"
33 " .set mips0 \n"
34 : "=&r" (retval), "=" GCC_OFF12_ASM() (*m), "=&r" (dummy)
35 : GCC_OFF12_ASM() (*m), "Jr" (val)
36 : "memory");
37 } else if (kernel_uses_llsc) {
38 unsigned long dummy;
39
40 do {
41 __asm__ __volatile__(
42 " .set arch=r4000 \n"
43 " ll %0, %3 # xchg_u32 \n"
44 " .set mips0 \n"
45 " move %2, %z4 \n"
46 " .set arch=r4000 \n"
47 " sc %2, %1 \n"
48 " .set mips0 \n"
49 : "=&r" (retval), "=" GCC_OFF12_ASM() (*m),
50 "=&r" (dummy)
51 : GCC_OFF12_ASM() (*m), "Jr" (val)
52 : "memory");
53 } while (unlikely(!dummy));
54 } else {
55 unsigned long flags;
56
57 raw_local_irq_save(flags);
58 retval = *m;
59 *m = val;
60 raw_local_irq_restore(flags);
61 }
62
63 smp_llsc_mb();
64
65 return retval;
66}
67
68#ifdef CONFIG_64BIT
69static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
70{
71 __u64 retval;
72
73 smp_mb__before_llsc();
74
75 if (kernel_uses_llsc && R10000_LLSC_WAR) {
76 unsigned long dummy;
77
78 __asm__ __volatile__(
79 " .set arch=r4000 \n"
80 "1: lld %0, %3 # xchg_u64 \n"
81 " move %2, %z4 \n"
82 " scd %2, %1 \n"
83 " beqzl %2, 1b \n"
84 " .set mips0 \n"
85 : "=&r" (retval), "=" GCC_OFF12_ASM() (*m), "=&r" (dummy)
86 : GCC_OFF12_ASM() (*m), "Jr" (val)
87 : "memory");
88 } else if (kernel_uses_llsc) {
89 unsigned long dummy;
90
91 do {
92 __asm__ __volatile__(
93 " .set arch=r4000 \n"
94 " lld %0, %3 # xchg_u64 \n"
95 " move %2, %z4 \n"
96 " scd %2, %1 \n"
97 " .set mips0 \n"
98 : "=&r" (retval), "=" GCC_OFF12_ASM() (*m),
99 "=&r" (dummy)
100 : GCC_OFF12_ASM() (*m), "Jr" (val)
101 : "memory");
102 } while (unlikely(!dummy));
103 } else {
104 unsigned long flags;
105
106 raw_local_irq_save(flags);
107 retval = *m;
108 *m = val;
109 raw_local_irq_restore(flags);
110 }
111
112 smp_llsc_mb();
113
114 return retval;
115}
116#else
117extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
118#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
119#endif
120
121static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
122{
123 switch (size) {
124 case 4:
125 return __xchg_u32(ptr, x);
126 case 8:
127 return __xchg_u64(ptr, x);
128 }
129
130 return x;
131}
132
133#define xchg(ptr, x) \
134({ \
135 BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc); \
136 \
137 ((__typeof__(*(ptr))) \
138 __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
139})
140
141#define __HAVE_ARCH_CMPXCHG 1
142
143#define __cmpxchg_asm(ld, st, m, old, new) \
144({ \
145 __typeof(*(m)) __ret; \
146 \
147 if (kernel_uses_llsc && R10000_LLSC_WAR) { \
148 __asm__ __volatile__( \
149 " .set push \n" \
150 " .set noat \n" \
151 " .set arch=r4000 \n" \
152 "1: " ld " %0, %2 # __cmpxchg_asm \n" \
153 " bne %0, %z3, 2f \n" \
154 " .set mips0 \n" \
155 " move $1, %z4 \n" \
156 " .set arch=r4000 \n" \
157 " " st " $1, %1 \n" \
158 " beqzl $1, 1b \n" \
159 "2: \n" \
160 " .set pop \n" \
161 : "=&r" (__ret), "=" GCC_OFF12_ASM() (*m) \
162 : GCC_OFF12_ASM() (*m), "Jr" (old), "Jr" (new) \
163 : "memory"); \
164 } else if (kernel_uses_llsc) { \
165 __asm__ __volatile__( \
166 " .set push \n" \
167 " .set noat \n" \
168 " .set arch=r4000 \n" \
169 "1: " ld " %0, %2 # __cmpxchg_asm \n" \
170 " bne %0, %z3, 2f \n" \
171 " .set mips0 \n" \
172 " move $1, %z4 \n" \
173 " .set arch=r4000 \n" \
174 " " st " $1, %1 \n" \
175 " beqz $1, 1b \n" \
176 " .set pop \n" \
177 "2: \n" \
178 : "=&r" (__ret), "=" GCC_OFF12_ASM() (*m) \
179 : GCC_OFF12_ASM() (*m), "Jr" (old), "Jr" (new) \
180 : "memory"); \
181 } else { \
182 unsigned long __flags; \
183 \
184 raw_local_irq_save(__flags); \
185 __ret = *m; \
186 if (__ret == old) \
187 *m = new; \
188 raw_local_irq_restore(__flags); \
189 } \
190 \
191 __ret; \
192})
193
194
195
196
197
198extern void __cmpxchg_called_with_bad_pointer(void);
199
200#define __cmpxchg(ptr, old, new, pre_barrier, post_barrier) \
201({ \
202 __typeof__(ptr) __ptr = (ptr); \
203 __typeof__(*(ptr)) __old = (old); \
204 __typeof__(*(ptr)) __new = (new); \
205 __typeof__(*(ptr)) __res = 0; \
206 \
207 pre_barrier; \
208 \
209 switch (sizeof(*(__ptr))) { \
210 case 4: \
211 __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
212 break; \
213 case 8: \
214 if (sizeof(long) == 8) { \
215 __res = __cmpxchg_asm("lld", "scd", __ptr, \
216 __old, __new); \
217 break; \
218 } \
219 default: \
220 __cmpxchg_called_with_bad_pointer(); \
221 break; \
222 } \
223 \
224 post_barrier; \
225 \
226 __res; \
227})
228
229#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb())
230#define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, , )
231
232#define cmpxchg64(ptr, o, n) \
233 ({ \
234 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
235 cmpxchg((ptr), (o), (n)); \
236 })
237
238#ifdef CONFIG_64BIT
239#define cmpxchg64_local(ptr, o, n) \
240 ({ \
241 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
242 cmpxchg_local((ptr), (o), (n)); \
243 })
244#else
245#include <asm-generic/cmpxchg-local.h>
246#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
247#endif
248
249#endif
250
