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 #include <linux/mmdebug.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         "       nop\n"                                                  \
  48         "       nop\n"                                                  \
  49         "       swp" #acq_lse #rel #sz "\t%" #w "3, %" #w "0, %2\n"     \
  50         "       nop\n"                                                  \
  51         "       " #nop_lse)                                             \
  52         : "=&r" (ret), "=&r" (tmp), "+Q" (*(u8 *)ptr)                   \
  53         : "r" (x)                                                       \
  54         : cl);                                                          \
  55                                                                         \
  56         return ret;                                                     \
  57 }
  58
  59 __XCHG_CASE(w, b,     1,        ,    ,  ,  ,  ,         )
  60 __XCHG_CASE(w, h,     2,        ,    ,  ,  ,  ,         )
  61 __XCHG_CASE(w,  ,     4,        ,    ,  ,  ,  ,         )
  62 __XCHG_CASE( ,  ,     8,        ,    ,  ,  ,  ,         )
  63 __XCHG_CASE(w, b, acq_1,        ,    , a, a,  , "memory")
  64 __XCHG_CASE(w, h, acq_2,        ,    , a, a,  , "memory")
  65 __XCHG_CASE(w,  , acq_4,        ,    , a, a,  , "memory")
  66 __XCHG_CASE( ,  , acq_8,        ,    , a, a,  , "memory")
  67 __XCHG_CASE(w, b, rel_1,        ,    ,  ,  , l, "memory")
  68 __XCHG_CASE(w, h, rel_2,        ,    ,  ,  , l, "memory")
  69 __XCHG_CASE(w,  , rel_4,        ,    ,  ,  , l, "memory")
  70 __XCHG_CASE( ,  , rel_8,        ,    ,  ,  , l, "memory")
  71 __XCHG_CASE(w, b,  mb_1, dmb ish, nop,  , a, l, "memory")
  72 __XCHG_CASE(w, h,  mb_2, dmb ish, nop,  , a, l, "memory")
  73 __XCHG_CASE(w,  ,  mb_4, dmb ish, nop,  , a, l, "memory")
  74 __XCHG_CASE( ,  ,  mb_8, dmb ish, nop,  , a, l, "memory")
  75
  76 #undef __XCHG_CASE
  77
  78 #define __XCHG_GEN(sfx)                                                 \
  79 static inline unsigned long __xchg##sfx(unsigned long x,                \
  80                                         volatile void *ptr,             \
  81                                         int size)                       \
  82 {                                                                       \
  83         switch (size) {                                                 \
  84         case 1:                                                         \
  85                 return __xchg_case##sfx##_1(x, ptr);                    \
  86         case 2:                                                         \
  87                 return __xchg_case##sfx##_2(x, ptr);                    \
  88         case 4:                                                         \
  89                 return __xchg_case##sfx##_4(x, ptr);                    \
  90         case 8:                                                         \
  91                 return __xchg_case##sfx##_8(x, ptr);                    \
  92         default:                                                        \
  93                 BUILD_BUG();                                            \
  94         }                                                               \
  95                                                                         \
  96         unreachable();                                                  \
  97 }
  98
  99 __XCHG_GEN()
 100 __XCHG_GEN(_acq)
 101 __XCHG_GEN(_rel)
 102 __XCHG_GEN(_mb)
 103
 104 #undef __XCHG_GEN
 105
 106 #define __xchg_wrapper(sfx, ptr, x)                                     \
 107 ({                                                                      \
 108         __typeof__(*(ptr)) __ret;                                       \
 109         __ret = (__typeof__(*(ptr)))                                    \
 110                 __xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
 111         __ret;                                                          \
 112 })
 113
 114 /* xchg */
 115 #define xchg_relaxed(...)       __xchg_wrapper(    , __VA_ARGS__)
 116 #define xchg_acquire(...)       __xchg_wrapper(_acq, __VA_ARGS__)
 117 #define xchg_release(...)       __xchg_wrapper(_rel, __VA_ARGS__)
 118 #define xchg(...)               __xchg_wrapper( _mb, __VA_ARGS__)
 119
 120 #define __CMPXCHG_GEN(sfx)                                              \
 121 static inline unsigned long __cmpxchg##sfx(volatile void *ptr,          \
 122                                            unsigned long old,           \
 123                                            unsigned long new,           \
 124                                            int size)                    \
 125 {                                                                       \
 126         switch (size) {                                                 \
 127         case 1:                                                         \
 128                 return __cmpxchg_case##sfx##_1(ptr, (u8)old, new);      \
 129         case 2:                                                         \
 130                 return __cmpxchg_case##sfx##_2(ptr, (u16)old, new);     \
 131         case 4:                                                         \
 132                 return __cmpxchg_case##sfx##_4(ptr, old, new);          \
 133         case 8:                                                         \
 134                 return __cmpxchg_case##sfx##_8(ptr, old, new);          \
 135         default:                                                        \
 136                 BUILD_BUG();                                            \
 137         }                                                               \
 138                                                                         \
 139         unreachable();                                                  \
 140 }
 141
 142 __CMPXCHG_GEN()
 143 __CMPXCHG_GEN(_acq)
 144 __CMPXCHG_GEN(_rel)
 145 __CMPXCHG_GEN(_mb)
 146
 147 #undef __CMPXCHG_GEN
 148
 149 #define __cmpxchg_wrapper(sfx, ptr, o, n)                               \
 150 ({                                                                      \
 151         __typeof__(*(ptr)) __ret;                                       \
 152         __ret = (__typeof__(*(ptr)))                                    \
 153                 __cmpxchg##sfx((ptr), (unsigned long)(o),               \
 154                                 (unsigned long)(n), sizeof(*(ptr)));    \
 155         __ret;                                                          \
 156 })
 157
 158 /* cmpxchg */
 159 #define cmpxchg_relaxed(...)    __cmpxchg_wrapper(    , __VA_ARGS__)
 160 #define cmpxchg_acquire(...)    __cmpxchg_wrapper(_acq, __VA_ARGS__)
 161 #define cmpxchg_release(...)    __cmpxchg_wrapper(_rel, __VA_ARGS__)
 162 #define cmpxchg(...)            __cmpxchg_wrapper( _mb, __VA_ARGS__)
 163 #define cmpxchg_local           cmpxchg_relaxed
 164
 165 /* cmpxchg64 */
 166 #define cmpxchg64_relaxed       cmpxchg_relaxed
 167 #define cmpxchg64_acquire       cmpxchg_acquire
 168 #define cmpxchg64_release       cmpxchg_release
 169 #define cmpxchg64               cmpxchg
 170 #define cmpxchg64_local         cmpxchg_local
 171
 172 /* cmpxchg_double */
 173 #define system_has_cmpxchg_double()     1
 174
 175 #define __cmpxchg_double_check(ptr1, ptr2)                                      \
 176 ({                                                                              \
 177         if (sizeof(*(ptr1)) != 8)                                               \
 178                 BUILD_BUG();                                                    \
 179         VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1);      \
 180 })
 181
 182 #define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \
 183 ({\
 184         int __ret;\
 185         __cmpxchg_double_check(ptr1, ptr2); \
 186         __ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2), \
 187                                      (unsigned long)(n1), (unsigned long)(n2), \
 188                                      ptr1); \
 189         __ret; \
 190 })
 191
 192 #define cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2) \
 193 ({\
 194         int __ret;\
 195         __cmpxchg_double_check(ptr1, ptr2); \
 196         __ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2), \
 197                                   (unsigned long)(n1), (unsigned long)(n2), \
 198                                   ptr1); \
 199         __ret; \
 200 })
 201
 202 /* this_cpu_cmpxchg */
 203 #define _protect_cmpxchg_local(pcp, o, n)                       \
 204 ({                                                              \
 205         typeof(*raw_cpu_ptr(&(pcp))) __ret;                     \
 206         preempt_disable();                                      \
 207         __ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n);       \
 208         preempt_enable();                                       \
 209         __ret;                                                  \
 210 })
 211
 212 #define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 213 #define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 214 #define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 215 #define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 216
 217 #define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2)           \
 218 ({                                                                      \
 219         int __ret;                                                      \
 220         preempt_disable();                                              \
 221         __ret = cmpxchg_double_local(   raw_cpu_ptr(&(ptr1)),           \
 222                                         raw_cpu_ptr(&(ptr2)),           \
 223                                         o1, o2, n1, n2);                \
 224         preempt_enable();                                               \
 225         __ret;                                                          \
 226 })
 227
 228 #endif  /* __ASM_CMPXCHG_H */