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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/llsc.h>
15#include <asm/sync.h>
16#include <asm/war.h>
17
18
19
20
21
22
23
24
25
26
27
28extern unsigned long __cmpxchg_called_with_bad_pointer(void)
29 __compiletime_error("Bad argument size for cmpxchg");
30extern unsigned long __cmpxchg64_unsupported(void)
31 __compiletime_error("cmpxchg64 not available; cpu_has_64bits may be false");
32extern unsigned long __xchg_called_with_bad_pointer(void)
33 __compiletime_error("Bad argument size for xchg");
34
35#define __xchg_asm(ld, st, m, val) \
36({ \
37 __typeof(*(m)) __ret; \
38 \
39 if (kernel_uses_llsc) { \
40 __asm__ __volatile__( \
41 " .set push \n" \
42 " .set noat \n" \
43 " .set push \n" \
44 " .set " MIPS_ISA_ARCH_LEVEL " \n" \
45 " " __SYNC(full, loongson3_war) " \n" \
46 "1: " ld " %0, %2 # __xchg_asm \n" \
47 " .set pop \n" \
48 " move $1, %z3 \n" \
49 " .set " MIPS_ISA_ARCH_LEVEL " \n" \
50 " " st " $1, %1 \n" \
51 "\t" __SC_BEQZ "$1, 1b \n" \
52 " .set pop \n" \
53 : "=&r" (__ret), "=" GCC_OFF_SMALL_ASM() (*m) \
54 : GCC_OFF_SMALL_ASM() (*m), "Jr" (val) \
55 : __LLSC_CLOBBER); \
56 } else { \
57 unsigned long __flags; \
58 \
59 raw_local_irq_save(__flags); \
60 __ret = *m; \
61 *m = val; \
62 raw_local_irq_restore(__flags); \
63 } \
64 \
65 __ret; \
66})
67
68extern unsigned long __xchg_small(volatile void *ptr, unsigned long val,
69 unsigned int size);
70
71static __always_inline
72unsigned long __xchg(volatile void *ptr, unsigned long x, int size)
73{
74 switch (size) {
75 case 1:
76 case 2:
77 return __xchg_small(ptr, x, size);
78
79 case 4:
80 return __xchg_asm("ll", "sc", (volatile u32 *)ptr, x);
81
82 case 8:
83 if (!IS_ENABLED(CONFIG_64BIT))
84 return __xchg_called_with_bad_pointer();
85
86 return __xchg_asm("lld", "scd", (volatile u64 *)ptr, x);
87
88 default:
89 return __xchg_called_with_bad_pointer();
90 }
91}
92
93#define arch_xchg(ptr, x) \
94({ \
95 __typeof__(*(ptr)) __res; \
96 \
97
98
99
100
101 \
102 if (__SYNC_loongson3_war == 0) \
103 smp_mb__before_llsc(); \
104 \
105 __res = (__typeof__(*(ptr))) \
106 __xchg((ptr), (unsigned long)(x), sizeof(*(ptr))); \
107 \
108 smp_llsc_mb(); \
109 \
110 __res; \
111})
112
113#define __cmpxchg_asm(ld, st, m, old, new) \
114({ \
115 __typeof(*(m)) __ret; \
116 \
117 if (kernel_uses_llsc) { \
118 __asm__ __volatile__( \
119 " .set push \n" \
120 " .set noat \n" \
121 " .set push \n" \
122 " .set "MIPS_ISA_ARCH_LEVEL" \n" \
123 " " __SYNC(full, loongson3_war) " \n" \
124 "1: " ld " %0, %2 # __cmpxchg_asm \n" \
125 " bne %0, %z3, 2f \n" \
126 " .set pop \n" \
127 " move $1, %z4 \n" \
128 " .set "MIPS_ISA_ARCH_LEVEL" \n" \
129 " " st " $1, %1 \n" \
130 "\t" __SC_BEQZ "$1, 1b \n" \
131 " .set pop \n" \
132 "2: " __SYNC(full, loongson3_war) " \n" \
133 : "=&r" (__ret), "=" GCC_OFF_SMALL_ASM() (*m) \
134 : GCC_OFF_SMALL_ASM() (*m), "Jr" (old), "Jr" (new) \
135 : __LLSC_CLOBBER); \
136 } else { \
137 unsigned long __flags; \
138 \
139 raw_local_irq_save(__flags); \
140 __ret = *m; \
141 if (__ret == old) \
142 *m = new; \
143 raw_local_irq_restore(__flags); \
144 } \
145 \
146 __ret; \
147})
148
149extern unsigned long __cmpxchg_small(volatile void *ptr, unsigned long old,
150 unsigned long new, unsigned int size);
151
152static __always_inline
153unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
154 unsigned long new, unsigned int size)
155{
156 switch (size) {
157 case 1:
158 case 2:
159 return __cmpxchg_small(ptr, old, new, size);
160
161 case 4:
162 return __cmpxchg_asm("ll", "sc", (volatile u32 *)ptr,
163 (u32)old, new);
164
165 case 8:
166
167 if (!IS_ENABLED(CONFIG_64BIT))
168 return __cmpxchg_called_with_bad_pointer();
169
170 return __cmpxchg_asm("lld", "scd", (volatile u64 *)ptr,
171 (u64)old, new);
172
173 default:
174 return __cmpxchg_called_with_bad_pointer();
175 }
176}
177
178#define arch_cmpxchg_local(ptr, old, new) \
179 ((__typeof__(*(ptr))) \
180 __cmpxchg((ptr), \
181 (unsigned long)(__typeof__(*(ptr)))(old), \
182 (unsigned long)(__typeof__(*(ptr)))(new), \
183 sizeof(*(ptr))))
184
185#define arch_cmpxchg(ptr, old, new) \
186({ \
187 __typeof__(*(ptr)) __res; \
188 \
189
190
191
192
193 \
194 if (__SYNC_loongson3_war == 0) \
195 smp_mb__before_llsc(); \
196 \
197 __res = arch_cmpxchg_local((ptr), (old), (new)); \
198 \
199
200
201
202
203 \
204 if (__SYNC_loongson3_war == 0) \
205 smp_llsc_mb(); \
206 \
207 __res; \
208})
209
210#ifdef CONFIG_64BIT
211#define arch_cmpxchg64_local(ptr, o, n) \
212 ({ \
213 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
214 arch_cmpxchg_local((ptr), (o), (n)); \
215 })
216
217#define arch_cmpxchg64(ptr, o, n) \
218 ({ \
219 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
220 arch_cmpxchg((ptr), (o), (n)); \
221 })
222#else
223
224# include <asm-generic/cmpxchg-local.h>
225# define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
226
227# ifdef CONFIG_SMP
228
229static inline unsigned long __cmpxchg64(volatile void *ptr,
230 unsigned long long old,
231 unsigned long long new)
232{
233 unsigned long long tmp, ret;
234 unsigned long flags;
235
236
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240
241
242
243
244 local_irq_save(flags);
245
246 asm volatile(
247 " .set push \n"
248 " .set " MIPS_ISA_ARCH_LEVEL " \n"
249
250 " " __SYNC(full, loongson3_war) " \n"
251 "1: lld %L0, %3 # __cmpxchg64 \n"
252
253
254
255
256 " dsra %M0, %L0, 32 \n"
257 " sll %L0, %L0, 0 \n"
258
259
260
261
262 " bne %M0, %M4, 2f \n"
263 " bne %L0, %L4, 2f \n"
264
265
266
267
268# if MIPS_ISA_REV >= 2
269 " move %L1, %L5 \n"
270 " dins %L1, %M5, 32, 32 \n"
271# else
272 " dsll %L1, %L5, 32 \n"
273 " dsrl %L1, %L1, 32 \n"
274 " .set noat \n"
275 " dsll $at, %M5, 32 \n"
276 " or %L1, %L1, $at \n"
277 " .set at \n"
278# endif
279
280 " scd %L1, %2 \n"
281
282 "\t" __SC_BEQZ "%L1, 1b \n"
283 " .set pop \n"
284 "2: " __SYNC(full, loongson3_war) " \n"
285 : "=&r"(ret),
286 "=&r"(tmp),
287 "=" GCC_OFF_SMALL_ASM() (*(unsigned long long *)ptr)
288 : GCC_OFF_SMALL_ASM() (*(unsigned long long *)ptr),
289 "r" (old),
290 "r" (new)
291 : "memory");
292
293 local_irq_restore(flags);
294 return ret;
295}
296
297# define arch_cmpxchg64(ptr, o, n) ({ \
298 unsigned long long __old = (__typeof__(*(ptr)))(o); \
299 unsigned long long __new = (__typeof__(*(ptr)))(n); \
300 __typeof__(*(ptr)) __res; \
301 \
302
303
304
305
306
307 \
308 if (cpu_has_64bits && kernel_uses_llsc) { \
309 smp_mb__before_llsc(); \
310 __res = __cmpxchg64((ptr), __old, __new); \
311 smp_llsc_mb(); \
312 } else { \
313 __res = __cmpxchg64_unsupported(); \
314 } \
315 \
316 __res; \
317})
318
319# else
320# define arch_cmpxchg64(ptr, o, n) arch_cmpxchg64_local((ptr), (o), (n))
321# endif
322#endif
323
324#endif
325