e825e61bbfe2f34722f691f2ed47642d27db50e7
[sfrench/cifs-2.6.git] / arch / arm64 / include / asm / cmpxchg.h
1 /*
2  * Based on arch/arm/include/asm/cmpxchg.h
3  *
4  * Copyright (C) 2012 ARM Ltd.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
17  */
18 #ifndef __ASM_CMPXCHG_H
19 #define __ASM_CMPXCHG_H
20
21 #include <linux/build_bug.h>
22 #include <linux/compiler.h>
23
24 #include <asm/atomic.h>
25 #include <asm/barrier.h>
26 #include <asm/lse.h>
27
28 /*
29  * We need separate acquire parameters for ll/sc and lse, since the full
30  * barrier case is generated as release+dmb for the former and
31  * acquire+release for the latter.
32  */
33 #define __XCHG_CASE(w, sz, name, mb, nop_lse, acq, acq_lse, rel, cl)    \
34 static inline unsigned long __xchg_case_##name(unsigned long x,         \
35                                                volatile void *ptr)      \
36 {                                                                       \
37         unsigned long ret, tmp;                                         \
38                                                                         \
39         asm volatile(ARM64_LSE_ATOMIC_INSN(                             \
40         /* LL/SC */                                                     \
41         "       prfm    pstl1strm, %2\n"                                \
42         "1:     ld" #acq "xr" #sz "\t%" #w "0, %2\n"                    \
43         "       st" #rel "xr" #sz "\t%w1, %" #w "3, %2\n"               \
44         "       cbnz    %w1, 1b\n"                                      \
45         "       " #mb,                                                  \
46         /* LSE atomics */                                               \
47         "       swp" #acq_lse #rel #sz "\t%" #w "3, %" #w "0, %2\n"     \
48                 __nops(3)                                               \
49         "       " #nop_lse)                                             \
50         : "=&r" (ret), "=&r" (tmp), "+Q" (*(unsigned long *)ptr)        \
51         : "r" (x)                                                       \
52         : cl);                                                          \
53                                                                         \
54         return ret;                                                     \
55 }
56
57 __XCHG_CASE(w, b,     1,        ,    ,  ,  ,  ,         )
58 __XCHG_CASE(w, h,     2,        ,    ,  ,  ,  ,         )
59 __XCHG_CASE(w,  ,     4,        ,    ,  ,  ,  ,         )
60 __XCHG_CASE( ,  ,     8,        ,    ,  ,  ,  ,         )
61 __XCHG_CASE(w, b, acq_1,        ,    , a, a,  , "memory")
62 __XCHG_CASE(w, h, acq_2,        ,    , a, a,  , "memory")
63 __XCHG_CASE(w,  , acq_4,        ,    , a, a,  , "memory")
64 __XCHG_CASE( ,  , acq_8,        ,    , a, a,  , "memory")
65 __XCHG_CASE(w, b, rel_1,        ,    ,  ,  , l, "memory")
66 __XCHG_CASE(w, h, rel_2,        ,    ,  ,  , l, "memory")
67 __XCHG_CASE(w,  , rel_4,        ,    ,  ,  , l, "memory")
68 __XCHG_CASE( ,  , rel_8,        ,    ,  ,  , l, "memory")
69 __XCHG_CASE(w, b,  mb_1, dmb ish, nop,  , a, l, "memory")
70 __XCHG_CASE(w, h,  mb_2, dmb ish, nop,  , a, l, "memory")
71 __XCHG_CASE(w,  ,  mb_4, dmb ish, nop,  , a, l, "memory")
72 __XCHG_CASE( ,  ,  mb_8, dmb ish, nop,  , a, l, "memory")
73
74 #undef __XCHG_CASE
75
76 #define __XCHG_GEN(sfx)                                                 \
77 static inline unsigned long __xchg##sfx(unsigned long x,                \
78                                         volatile void *ptr,             \
79                                         int size)                       \
80 {                                                                       \
81         switch (size) {                                                 \
82         case 1:                                                         \
83                 return __xchg_case##sfx##_1(x, ptr);                    \
84         case 2:                                                         \
85                 return __xchg_case##sfx##_2(x, ptr);                    \
86         case 4:                                                         \
87                 return __xchg_case##sfx##_4(x, ptr);                    \
88         case 8:                                                         \
89                 return __xchg_case##sfx##_8(x, ptr);                    \
90         default:                                                        \
91                 BUILD_BUG();                                            \
92         }                                                               \
93                                                                         \
94         unreachable();                                                  \
95 }
96
97 __XCHG_GEN()
98 __XCHG_GEN(_acq)
99 __XCHG_GEN(_rel)
100 __XCHG_GEN(_mb)
101
102 #undef __XCHG_GEN
103
104 #define __xchg_wrapper(sfx, ptr, x)                                     \
105 ({                                                                      \
106         __typeof__(*(ptr)) __ret;                                       \
107         __ret = (__typeof__(*(ptr)))                                    \
108                 __xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
109         __ret;                                                          \
110 })
111
112 /* xchg */
113 #define arch_xchg_relaxed(...)  __xchg_wrapper(    , __VA_ARGS__)
114 #define arch_xchg_acquire(...)  __xchg_wrapper(_acq, __VA_ARGS__)
115 #define arch_xchg_release(...)  __xchg_wrapper(_rel, __VA_ARGS__)
116 #define arch_xchg(...)          __xchg_wrapper( _mb, __VA_ARGS__)
117
118 #define __CMPXCHG_GEN(sfx)                                              \
119 static inline unsigned long __cmpxchg##sfx(volatile void *ptr,          \
120                                            unsigned long old,           \
121                                            unsigned long new,           \
122                                            int size)                    \
123 {                                                                       \
124         switch (size) {                                                 \
125         case 1:                                                         \
126                 return __cmpxchg_case##sfx##_1(ptr, (u8)old, new);      \
127         case 2:                                                         \
128                 return __cmpxchg_case##sfx##_2(ptr, (u16)old, new);     \
129         case 4:                                                         \
130                 return __cmpxchg_case##sfx##_4(ptr, old, new);          \
131         case 8:                                                         \
132                 return __cmpxchg_case##sfx##_8(ptr, old, new);          \
133         default:                                                        \
134                 BUILD_BUG();                                            \
135         }                                                               \
136                                                                         \
137         unreachable();                                                  \
138 }
139
140 __CMPXCHG_GEN()
141 __CMPXCHG_GEN(_acq)
142 __CMPXCHG_GEN(_rel)
143 __CMPXCHG_GEN(_mb)
144
145 #undef __CMPXCHG_GEN
146
147 #define __cmpxchg_wrapper(sfx, ptr, o, n)                               \
148 ({                                                                      \
149         __typeof__(*(ptr)) __ret;                                       \
150         __ret = (__typeof__(*(ptr)))                                    \
151                 __cmpxchg##sfx((ptr), (unsigned long)(o),               \
152                                 (unsigned long)(n), sizeof(*(ptr)));    \
153         __ret;                                                          \
154 })
155
156 /* cmpxchg */
157 #define arch_cmpxchg_relaxed(...)       __cmpxchg_wrapper(    , __VA_ARGS__)
158 #define arch_cmpxchg_acquire(...)       __cmpxchg_wrapper(_acq, __VA_ARGS__)
159 #define arch_cmpxchg_release(...)       __cmpxchg_wrapper(_rel, __VA_ARGS__)
160 #define arch_cmpxchg(...)               __cmpxchg_wrapper( _mb, __VA_ARGS__)
161 #define arch_cmpxchg_local              arch_cmpxchg_relaxed
162
163 /* cmpxchg64 */
164 #define arch_cmpxchg64_relaxed          arch_cmpxchg_relaxed
165 #define arch_cmpxchg64_acquire          arch_cmpxchg_acquire
166 #define arch_cmpxchg64_release          arch_cmpxchg_release
167 #define arch_cmpxchg64                  arch_cmpxchg
168 #define arch_cmpxchg64_local            arch_cmpxchg_local
169
170 /* cmpxchg_double */
171 #define system_has_cmpxchg_double()     1
172
173 #define __cmpxchg_double_check(ptr1, ptr2)                                      \
174 ({                                                                              \
175         if (sizeof(*(ptr1)) != 8)                                               \
176                 BUILD_BUG();                                                    \
177         VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1);      \
178 })
179
180 #define arch_cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2)                         \
181 ({                                                                              \
182         int __ret;                                                              \
183         __cmpxchg_double_check(ptr1, ptr2);                                     \
184         __ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2),  \
185                                      (unsigned long)(n1), (unsigned long)(n2),  \
186                                      ptr1);                                     \
187         __ret;                                                                  \
188 })
189
190 #define arch_cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2)                   \
191 ({                                                                              \
192         int __ret;                                                              \
193         __cmpxchg_double_check(ptr1, ptr2);                                     \
194         __ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2),     \
195                                   (unsigned long)(n1), (unsigned long)(n2),     \
196                                   ptr1);                                        \
197         __ret;                                                                  \
198 })
199
200 #define __CMPWAIT_CASE(w, sz, name)                                     \
201 static inline void __cmpwait_case_##name(volatile void *ptr,            \
202                                          unsigned long val)             \
203 {                                                                       \
204         unsigned long tmp;                                              \
205                                                                         \
206         asm volatile(                                                   \
207         "       sevl\n"                                                 \
208         "       wfe\n"                                                  \
209         "       ldxr" #sz "\t%" #w "[tmp], %[v]\n"                      \
210         "       eor     %" #w "[tmp], %" #w "[tmp], %" #w "[val]\n"     \
211         "       cbnz    %" #w "[tmp], 1f\n"                             \
212         "       wfe\n"                                                  \
213         "1:"                                                            \
214         : [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr)           \
215         : [val] "r" (val));                                             \
216 }
217
218 __CMPWAIT_CASE(w, b, 1);
219 __CMPWAIT_CASE(w, h, 2);
220 __CMPWAIT_CASE(w,  , 4);
221 __CMPWAIT_CASE( ,  , 8);
222
223 #undef __CMPWAIT_CASE
224
225 #define __CMPWAIT_GEN(sfx)                                              \
226 static inline void __cmpwait##sfx(volatile void *ptr,                   \
227                                   unsigned long val,                    \
228                                   int size)                             \
229 {                                                                       \
230         switch (size) {                                                 \
231         case 1:                                                         \
232                 return __cmpwait_case##sfx##_1(ptr, (u8)val);           \
233         case 2:                                                         \
234                 return __cmpwait_case##sfx##_2(ptr, (u16)val);          \
235         case 4:                                                         \
236                 return __cmpwait_case##sfx##_4(ptr, val);               \
237         case 8:                                                         \
238                 return __cmpwait_case##sfx##_8(ptr, val);               \
239         default:                                                        \
240                 BUILD_BUG();                                            \
241         }                                                               \
242                                                                         \
243         unreachable();                                                  \
244 }
245
246 __CMPWAIT_GEN()
247
248 #undef __CMPWAIT_GEN
249
250 #define __cmpwait_relaxed(ptr, val) \
251         __cmpwait((ptr), (unsigned long)(val), sizeof(*(ptr)))
252
253 #endif  /* __ASM_CMPXCHG_H */