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/bug.h>
  22
  23 #include <asm/atomic.h>
  24 #include <asm/barrier.h>
  25 #include <asm/lse.h>
  26
  27 /*
  28  * We need separate acquire parameters for ll/sc and lse, since the full
  29  * barrier case is generated as release+dmb for the former and
  30  * acquire+release for the latter.
  31  */
  32 #define __XCHG_CASE(w, sz, name, mb, nop_lse, acq, acq_lse, rel, cl)    \
  33 static inline unsigned long __xchg_case_##name(unsigned long x,         \
  34                                                volatile void *ptr)      \
  35 {                                                                       \
  36         unsigned long ret, tmp;                                         \
  37                                                                         \
  38         asm volatile(ARM64_LSE_ATOMIC_INSN(                             \
  39         /* LL/SC */                                                     \
  40         "       prfm    pstl1strm, %2\n"                                \
  41         "1:     ld" #acq "xr" #sz "\t%" #w "0, %2\n"                    \
  42         "       st" #rel "xr" #sz "\t%w1, %" #w "3, %2\n"               \
  43         "       cbnz    %w1, 1b\n"                                      \
  44         "       " #mb,                                                  \
  45         /* LSE atomics */                                               \
  46         "       swp" #acq_lse #rel #sz "\t%" #w "3, %" #w "0, %2\n"     \
  47                 __nops(3)                                               \
  48         "       " #nop_lse)                                             \
  49         : "=&r" (ret), "=&r" (tmp), "+Q" (*(u8 *)ptr)                   \
  50         : "r" (x)                                                       \
  51         : cl);                                                          \
  52                                                                         \
  53         return ret;                                                     \
  54 }
  55
  56 __XCHG_CASE(w, b,     1,        ,    ,  ,  ,  ,         )
  57 __XCHG_CASE(w, h,     2,        ,    ,  ,  ,  ,         )
  58 __XCHG_CASE(w,  ,     4,        ,    ,  ,  ,  ,         )
  59 __XCHG_CASE( ,  ,     8,        ,    ,  ,  ,  ,         )
  60 __XCHG_CASE(w, b, acq_1,        ,    , a, a,  , "memory")
  61 __XCHG_CASE(w, h, acq_2,        ,    , a, a,  , "memory")
  62 __XCHG_CASE(w,  , acq_4,        ,    , a, a,  , "memory")
  63 __XCHG_CASE( ,  , acq_8,        ,    , a, a,  , "memory")
  64 __XCHG_CASE(w, b, rel_1,        ,    ,  ,  , l, "memory")
  65 __XCHG_CASE(w, h, rel_2,        ,    ,  ,  , l, "memory")
  66 __XCHG_CASE(w,  , rel_4,        ,    ,  ,  , l, "memory")
  67 __XCHG_CASE( ,  , rel_8,        ,    ,  ,  , l, "memory")
  68 __XCHG_CASE(w, b,  mb_1, dmb ish, nop,  , a, l, "memory")
  69 __XCHG_CASE(w, h,  mb_2, dmb ish, nop,  , a, l, "memory")
  70 __XCHG_CASE(w,  ,  mb_4, dmb ish, nop,  , a, l, "memory")
  71 __XCHG_CASE( ,  ,  mb_8, dmb ish, nop,  , a, l, "memory")
  72
  73 #undef __XCHG_CASE
  74
  75 #define __XCHG_GEN(sfx)                                                 \
  76 static inline unsigned long __xchg##sfx(unsigned long x,                \
  77                                         volatile void *ptr,             \
  78                                         int size)                       \
  79 {                                                                       \
  80         switch (size) {                                                 \
  81         case 1:                                                         \
  82                 return __xchg_case##sfx##_1(x, ptr);                    \
  83         case 2:                                                         \
  84                 return __xchg_case##sfx##_2(x, ptr);                    \
  85         case 4:                                                         \
  86                 return __xchg_case##sfx##_4(x, ptr);                    \
  87         case 8:                                                         \
  88                 return __xchg_case##sfx##_8(x, ptr);                    \
  89         default:                                                        \
  90                 BUILD_BUG();                                            \
  91         }                                                               \
  92                                                                         \
  93         unreachable();                                                  \
  94 }
  95
  96 __XCHG_GEN()
  97 __XCHG_GEN(_acq)
  98 __XCHG_GEN(_rel)
  99 __XCHG_GEN(_mb)
 100
 101 #undef __XCHG_GEN
 102
 103 #define __xchg_wrapper(sfx, ptr, x)                                     \
 104 ({                                                                      \
 105         __typeof__(*(ptr)) __ret;                                       \
 106         __ret = (__typeof__(*(ptr)))                                    \
 107                 __xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
 108         __ret;                                                          \
 109 })
 110
 111 /* xchg */
 112 #define xchg_relaxed(...)       __xchg_wrapper(    , __VA_ARGS__)
 113 #define xchg_acquire(...)       __xchg_wrapper(_acq, __VA_ARGS__)
 114 #define xchg_release(...)       __xchg_wrapper(_rel, __VA_ARGS__)
 115 #define xchg(...)               __xchg_wrapper( _mb, __VA_ARGS__)
 116
 117 #define __CMPXCHG_GEN(sfx)                                              \
 118 static inline unsigned long __cmpxchg##sfx(volatile void *ptr,          \
 119                                            unsigned long old,           \
 120                                            unsigned long new,           \
 121                                            int size)                    \
 122 {                                                                       \
 123         switch (size) {                                                 \
 124         case 1:                                                         \
 125                 return __cmpxchg_case##sfx##_1(ptr, (u8)old, new);      \
 126         case 2:                                                         \
 127                 return __cmpxchg_case##sfx##_2(ptr, (u16)old, new);     \
 128         case 4:                                                         \
 129                 return __cmpxchg_case##sfx##_4(ptr, old, new);          \
 130         case 8:                                                         \
 131                 return __cmpxchg_case##sfx##_8(ptr, old, new);          \
 132         default:                                                        \
 133                 BUILD_BUG();                                            \
 134         }                                                               \
 135                                                                         \
 136         unreachable();                                                  \
 137 }
 138
 139 __CMPXCHG_GEN()
 140 __CMPXCHG_GEN(_acq)
 141 __CMPXCHG_GEN(_rel)
 142 __CMPXCHG_GEN(_mb)
 143
 144 #undef __CMPXCHG_GEN
 145
 146 #define __cmpxchg_wrapper(sfx, ptr, o, n)                               \
 147 ({                                                                      \
 148         __typeof__(*(ptr)) __ret;                                       \
 149         __ret = (__typeof__(*(ptr)))                                    \
 150                 __cmpxchg##sfx((ptr), (unsigned long)(o),               \
 151                                 (unsigned long)(n), sizeof(*(ptr)));    \
 152         __ret;                                                          \
 153 })
 154
 155 /* cmpxchg */
 156 #define cmpxchg_relaxed(...)    __cmpxchg_wrapper(    , __VA_ARGS__)
 157 #define cmpxchg_acquire(...)    __cmpxchg_wrapper(_acq, __VA_ARGS__)
 158 #define cmpxchg_release(...)    __cmpxchg_wrapper(_rel, __VA_ARGS__)
 159 #define cmpxchg(...)            __cmpxchg_wrapper( _mb, __VA_ARGS__)
 160 #define cmpxchg_local           cmpxchg_relaxed
 161
 162 /* cmpxchg64 */
 163 #define cmpxchg64_relaxed       cmpxchg_relaxed
 164 #define cmpxchg64_acquire       cmpxchg_acquire
 165 #define cmpxchg64_release       cmpxchg_release
 166 #define cmpxchg64               cmpxchg
 167 #define cmpxchg64_local         cmpxchg_local
 168
 169 /* cmpxchg_double */
 170 #define system_has_cmpxchg_double()     1
 171
 172 #define __cmpxchg_double_check(ptr1, ptr2)                                      \
 173 ({                                                                              \
 174         if (sizeof(*(ptr1)) != 8)                                               \
 175                 BUILD_BUG();                                                    \
 176         VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1);      \
 177 })
 178
 179 #define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \
 180 ({\
 181         int __ret;\
 182         __cmpxchg_double_check(ptr1, ptr2); \
 183         __ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2), \
 184                                      (unsigned long)(n1), (unsigned long)(n2), \
 185                                      ptr1); \
 186         __ret; \
 187 })
 188
 189 #define cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2) \
 190 ({\
 191         int __ret;\
 192         __cmpxchg_double_check(ptr1, ptr2); \
 193         __ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2), \
 194                                   (unsigned long)(n1), (unsigned long)(n2), \
 195                                   ptr1); \
 196         __ret; \
 197 })
 198
 199 /* this_cpu_cmpxchg */
 200 #define _protect_cmpxchg_local(pcp, o, n)                       \
 201 ({                                                              \
 202         typeof(*raw_cpu_ptr(&(pcp))) __ret;                     \
 203         preempt_disable();                                      \
 204         __ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n);       \
 205         preempt_enable();                                       \
 206         __ret;                                                  \
 207 })
 208
 209 #define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 210 #define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 211 #define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 212 #define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 213
 214 #define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2)           \
 215 ({                                                                      \
 216         int __ret;                                                      \
 217         preempt_disable();                                              \
 218         __ret = cmpxchg_double_local(   raw_cpu_ptr(&(ptr1)),           \
 219                                         raw_cpu_ptr(&(ptr2)),           \
 220                                         o1, o2, n1, n2);                \
 221         preempt_enable();                                               \
 222         __ret;                                                          \
 223 })
 224
 225 #define __CMPWAIT_CASE(w, sz, name)                                     \
 226 static inline void __cmpwait_case_##name(volatile void *ptr,            \
 227                                          unsigned long val)             \
 228 {                                                                       \
 229         unsigned long tmp;                                              \
 230                                                                         \
 231         asm volatile(                                                   \
 232         "       ldxr" #sz "\t%" #w "[tmp], %[v]\n"              \
 233         "       eor     %" #w "[tmp], %" #w "[tmp], %" #w "[val]\n"     \
 234         "       cbnz    %" #w "[tmp], 1f\n"                             \
 235         "       wfe\n"                                                  \
 236         "1:"                                                            \
 237         : [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr)           \
 238         : [val] "r" (val));                                             \
 239 }
 240
 241 __CMPWAIT_CASE(w, b, 1);
 242 __CMPWAIT_CASE(w, h, 2);
 243 __CMPWAIT_CASE(w,  , 4);
 244 __CMPWAIT_CASE( ,  , 8);
 245
 246 #undef __CMPWAIT_CASE
 247
 248 #define __CMPWAIT_GEN(sfx)                                              \
 249 static inline void __cmpwait##sfx(volatile void *ptr,                   \
 250                                   unsigned long val,                    \
 251                                   int size)                             \
 252 {                                                                       \
 253         switch (size) {                                                 \
 254         case 1:                                                         \
 255                 return __cmpwait_case##sfx##_1(ptr, (u8)val);           \
 256         case 2:                                                         \
 257                 return __cmpwait_case##sfx##_2(ptr, (u16)val);          \
 258         case 4:                                                         \
 259                 return __cmpwait_case##sfx##_4(ptr, val);               \
 260         case 8:                                                         \
 261                 return __cmpwait_case##sfx##_8(ptr, val);               \
 262         default:                                                        \
 263                 BUILD_BUG();                                            \
 264         }                                                               \
 265                                                                         \
 266         unreachable();                                                  \
 267 }
 268
 269 __CMPWAIT_GEN()
 270
 271 #undef __CMPWAIT_GEN
 272
 273 #define __cmpwait_relaxed(ptr, val) \
 274         __cmpwait((ptr), (unsigned long)(val), sizeof(*(ptr)))
 275
 276 #endif  /* __ASM_CMPXCHG_H */