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, sfx, name, sz, mb, nop_lse, acq, acq_lse, rel, cl)       \
  34 static inline u##sz __xchg_case_##name##sz(u##sz x, volatile void *ptr)         \
  35 {                                                                               \
  36         u##sz ret;                                                              \
  37         unsigned long tmp;                                                      \
  38                                                                                 \
  39         asm volatile(ARM64_LSE_ATOMIC_INSN(                                     \
  40         /* LL/SC */                                                             \
  41         "       prfm    pstl1strm, %2\n"                                        \
  42         "1:     ld" #acq "xr" #sfx "\t%" #w "0, %2\n"                           \
  43         "       st" #rel "xr" #sfx "\t%w1, %" #w "3, %2\n"                      \
  44         "       cbnz    %w1, 1b\n"                                              \
  45         "       " #mb,                                                          \
  46         /* LSE atomics */                                                       \
  47         "       swp" #acq_lse #rel #sfx "\t%" #w "3, %" #w "0, %2\n"            \
  48                 __nops(3)                                                       \
  49         "       " #nop_lse)                                                     \
  50         : "=&r" (ret), "=&r" (tmp), "+Q" (*(u##sz *)ptr)                        \
  51         : "r" (x)                                                               \
  52         : cl);                                                                  \
  53                                                                                 \
  54         return ret;                                                             \
  55 }
  56
  57 __XCHG_CASE(w, b,     ,  8,        ,    ,  ,  ,  ,         )
  58 __XCHG_CASE(w, h,     , 16,        ,    ,  ,  ,  ,         )
  59 __XCHG_CASE(w,  ,     , 32,        ,    ,  ,  ,  ,         )
  60 __XCHG_CASE( ,  ,     , 64,        ,    ,  ,  ,  ,         )
  61 __XCHG_CASE(w, b, acq_,  8,        ,    , a, a,  , "memory")
  62 __XCHG_CASE(w, h, acq_, 16,        ,    , a, a,  , "memory")
  63 __XCHG_CASE(w,  , acq_, 32,        ,    , a, a,  , "memory")
  64 __XCHG_CASE( ,  , acq_, 64,        ,    , a, a,  , "memory")
  65 __XCHG_CASE(w, b, rel_,  8,        ,    ,  ,  , l, "memory")
  66 __XCHG_CASE(w, h, rel_, 16,        ,    ,  ,  , l, "memory")
  67 __XCHG_CASE(w,  , rel_, 32,        ,    ,  ,  , l, "memory")
  68 __XCHG_CASE( ,  , rel_, 64,        ,    ,  ,  , l, "memory")
  69 __XCHG_CASE(w, b,  mb_,  8, dmb ish, nop,  , a, l, "memory")
  70 __XCHG_CASE(w, h,  mb_, 16, dmb ish, nop,  , a, l, "memory")
  71 __XCHG_CASE(w,  ,  mb_, 32, dmb ish, nop,  , a, l, "memory")
  72 __XCHG_CASE( ,  ,  mb_, 64, 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##_8(x, ptr);                    \
  84         case 2:                                                         \
  85                 return __xchg_case##sfx##_16(x, ptr);                   \
  86         case 4:                                                         \
  87                 return __xchg_case##sfx##_32(x, ptr);                   \
  88         case 8:                                                         \
  89                 return __xchg_case##sfx##_64(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 xchg_relaxed(...)       __xchg_wrapper(    , __VA_ARGS__)
 114 #define xchg_acquire(...)       __xchg_wrapper(_acq, __VA_ARGS__)
 115 #define xchg_release(...)       __xchg_wrapper(_rel, __VA_ARGS__)
 116 #define 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##_8(ptr, old, new);          \
 127         case 2:                                                         \
 128                 return __cmpxchg_case##sfx##_16(ptr, old, new);         \
 129         case 4:                                                         \
 130                 return __cmpxchg_case##sfx##_32(ptr, old, new);         \
 131         case 8:                                                         \
 132                 return __cmpxchg_case##sfx##_64(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 cmpxchg_relaxed(...)    __cmpxchg_wrapper(    , __VA_ARGS__)
 158 #define cmpxchg_acquire(...)    __cmpxchg_wrapper(_acq, __VA_ARGS__)
 159 #define cmpxchg_release(...)    __cmpxchg_wrapper(_rel, __VA_ARGS__)
 160 #define cmpxchg(...)            __cmpxchg_wrapper( _mb, __VA_ARGS__)
 161 #define cmpxchg_local           cmpxchg_relaxed
 162
 163 /* cmpxchg64 */
 164 #define cmpxchg64_relaxed       cmpxchg_relaxed
 165 #define cmpxchg64_acquire       cmpxchg_acquire
 166 #define cmpxchg64_release       cmpxchg_release
 167 #define cmpxchg64               cmpxchg
 168 #define cmpxchg64_local         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 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 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, sfx, sz)                                      \
 201 static inline void __cmpwait_case_##sz(volatile void *ptr,              \
 202                                        unsigned long val)               \
 203 {                                                                       \
 204         unsigned long tmp;                                              \
 205                                                                         \
 206         asm volatile(                                                   \
 207         "       sevl\n"                                                 \
 208         "       wfe\n"                                                  \
 209         "       ldxr" #sfx "\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, 8);
 219 __CMPWAIT_CASE(w, h, 16);
 220 __CMPWAIT_CASE(w,  , 32);
 221 __CMPWAIT_CASE( ,  , 64);
 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##_8(ptr, (u8)val);           \
 233         case 2:                                                         \
 234                 return __cmpwait_case##sfx##_16(ptr, (u16)val);         \
 235         case 4:                                                         \
 236                 return __cmpwait_case##sfx##_32(ptr, val);              \
 237         case 8:                                                         \
 238                 return __cmpwait_case##sfx##_64(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 */