arch/arm64/include/asm/percpu.h

   1 /*
   2  * Copyright (C) 2013 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16 #ifndef __ASM_PERCPU_H
  17 #define __ASM_PERCPU_H
  18
  19 static inline void set_my_cpu_offset(unsigned long off)
  20 {
  21         asm volatile("msr tpidr_el1, %0" :: "r" (off) : "memory");
  22 }
  23
  24 static inline unsigned long __my_cpu_offset(void)
  25 {
  26         unsigned long off;
  27
  28         /*
  29          * We want to allow caching the value, so avoid using volatile and
  30          * instead use a fake stack read to hazard against barrier().
  31          */
  32         asm("mrs %0, tpidr_el1" : "=r" (off) :
  33                 "Q" (*(const unsigned long *)current_stack_pointer));
  34
  35         return off;
  36 }
  37 #define __my_cpu_offset __my_cpu_offset()
  38
  39 #define PERCPU_OP(op, asm_op)                                           \
  40 static inline unsigned long __percpu_##op(void *ptr,                    \
  41                         unsigned long val, int size)                    \
  42 {                                                                       \
  43         unsigned long loop, ret;                                        \
  44                                                                         \
  45         switch (size) {                                                 \
  46         case 1:                                                         \
  47                 asm ("//__per_cpu_" #op "_1\n"                          \
  48                 "1:     ldxrb     %w[ret], %[ptr]\n"                    \
  49                         #asm_op " %w[ret], %w[ret], %w[val]\n"          \
  50                 "       stxrb     %w[loop], %w[ret], %[ptr]\n"          \
  51                 "       cbnz      %w[loop], 1b"                         \
  52                 : [loop] "=&r" (loop), [ret] "=&r" (ret),               \
  53                   [ptr] "+Q"(*(u8 *)ptr)                                \
  54                 : [val] "Ir" (val));                                    \
  55                 break;                                                  \
  56         case 2:                                                         \
  57                 asm ("//__per_cpu_" #op "_2\n"                          \
  58                 "1:     ldxrh     %w[ret], %[ptr]\n"                    \
  59                         #asm_op " %w[ret], %w[ret], %w[val]\n"          \
  60                 "       stxrh     %w[loop], %w[ret], %[ptr]\n"          \
  61                 "       cbnz      %w[loop], 1b"                         \
  62                 : [loop] "=&r" (loop), [ret] "=&r" (ret),               \
  63                   [ptr]  "+Q"(*(u16 *)ptr)                              \
  64                 : [val] "Ir" (val));                                    \
  65                 break;                                                  \
  66         case 4:                                                         \
  67                 asm ("//__per_cpu_" #op "_4\n"                          \
  68                 "1:     ldxr      %w[ret], %[ptr]\n"                    \
  69                         #asm_op " %w[ret], %w[ret], %w[val]\n"          \
  70                 "       stxr      %w[loop], %w[ret], %[ptr]\n"          \
  71                 "       cbnz      %w[loop], 1b"                         \
  72                 : [loop] "=&r" (loop), [ret] "=&r" (ret),               \
  73                   [ptr] "+Q"(*(u32 *)ptr)                               \
  74                 : [val] "Ir" (val));                                    \
  75                 break;                                                  \
  76         case 8:                                                         \
  77                 asm ("//__per_cpu_" #op "_8\n"                          \
  78                 "1:     ldxr      %[ret], %[ptr]\n"                     \
  79                         #asm_op " %[ret], %[ret], %[val]\n"             \
  80                 "       stxr      %w[loop], %[ret], %[ptr]\n"           \
  81                 "       cbnz      %w[loop], 1b"                         \
  82                 : [loop] "=&r" (loop), [ret] "=&r" (ret),               \
  83                   [ptr] "+Q"(*(u64 *)ptr)                               \
  84                 : [val] "Ir" (val));                                    \
  85                 break;                                                  \
  86         default:                                                        \
  87                 ret = 0;                                                \
  88                 BUILD_BUG();                                            \
  89         }                                                               \
  90                                                                         \
  91         return ret;                                                     \
  92 }
  93
  94 PERCPU_OP(add, add)
  95 PERCPU_OP(and, and)
  96 PERCPU_OP(or, orr)
  97 #undef PERCPU_OP
  98
  99 static inline unsigned long __percpu_read(void *ptr, int size)
 100 {
 101         unsigned long ret;
 102
 103         switch (size) {
 104         case 1:
 105                 ret = ACCESS_ONCE(*(u8 *)ptr);
 106                 break;
 107         case 2:
 108                 ret = ACCESS_ONCE(*(u16 *)ptr);
 109                 break;
 110         case 4:
 111                 ret = ACCESS_ONCE(*(u32 *)ptr);
 112                 break;
 113         case 8:
 114                 ret = ACCESS_ONCE(*(u64 *)ptr);
 115                 break;
 116         default:
 117                 ret = 0;
 118                 BUILD_BUG();
 119         }
 120
 121         return ret;
 122 }
 123
 124 static inline void __percpu_write(void *ptr, unsigned long val, int size)
 125 {
 126         switch (size) {
 127         case 1:
 128                 ACCESS_ONCE(*(u8 *)ptr) = (u8)val;
 129                 break;
 130         case 2:
 131                 ACCESS_ONCE(*(u16 *)ptr) = (u16)val;
 132                 break;
 133         case 4:
 134                 ACCESS_ONCE(*(u32 *)ptr) = (u32)val;
 135                 break;
 136         case 8:
 137                 ACCESS_ONCE(*(u64 *)ptr) = (u64)val;
 138                 break;
 139         default:
 140                 BUILD_BUG();
 141         }
 142 }
 143
 144 static inline unsigned long __percpu_xchg(void *ptr, unsigned long val,
 145                                                 int size)
 146 {
 147         unsigned long ret, loop;
 148
 149         switch (size) {
 150         case 1:
 151                 asm ("//__percpu_xchg_1\n"
 152                 "1:     ldxrb   %w[ret], %[ptr]\n"
 153                 "       stxrb   %w[loop], %w[val], %[ptr]\n"
 154                 "       cbnz    %w[loop], 1b"
 155                 : [loop] "=&r"(loop), [ret] "=&r"(ret),
 156                   [ptr] "+Q"(*(u8 *)ptr)
 157                 : [val] "r" (val));
 158                 break;
 159         case 2:
 160                 asm ("//__percpu_xchg_2\n"
 161                 "1:     ldxrh   %w[ret], %[ptr]\n"
 162                 "       stxrh   %w[loop], %w[val], %[ptr]\n"
 163                 "       cbnz    %w[loop], 1b"
 164                 : [loop] "=&r"(loop), [ret] "=&r"(ret),
 165                   [ptr] "+Q"(*(u16 *)ptr)
 166                 : [val] "r" (val));
 167                 break;
 168         case 4:
 169                 asm ("//__percpu_xchg_4\n"
 170                 "1:     ldxr    %w[ret], %[ptr]\n"
 171                 "       stxr    %w[loop], %w[val], %[ptr]\n"
 172                 "       cbnz    %w[loop], 1b"
 173                 : [loop] "=&r"(loop), [ret] "=&r"(ret),
 174                   [ptr] "+Q"(*(u32 *)ptr)
 175                 : [val] "r" (val));
 176                 break;
 177         case 8:
 178                 asm ("//__percpu_xchg_8\n"
 179                 "1:     ldxr    %[ret], %[ptr]\n"
 180                 "       stxr    %w[loop], %[val], %[ptr]\n"
 181                 "       cbnz    %w[loop], 1b"
 182                 : [loop] "=&r"(loop), [ret] "=&r"(ret),
 183                   [ptr] "+Q"(*(u64 *)ptr)
 184                 : [val] "r" (val));
 185                 break;
 186         default:
 187                 ret = 0;
 188                 BUILD_BUG();
 189         }
 190
 191         return ret;
 192 }
 193
 194 #define _percpu_read(pcp)                                               \
 195 ({                                                                      \
 196         typeof(pcp) __retval;                                           \
 197         preempt_disable();                                              \
 198         __retval = (typeof(pcp))__percpu_read(raw_cpu_ptr(&(pcp)),      \
 199                                               sizeof(pcp));             \
 200         preempt_enable();                                               \
 201         __retval;                                                       \
 202 })
 203
 204 #define _percpu_write(pcp, val)                                         \
 205 do {                                                                    \
 206         preempt_disable();                                              \
 207         __percpu_write(raw_cpu_ptr(&(pcp)), (unsigned long)(val),       \
 208                                 sizeof(pcp));                           \
 209         preempt_enable();                                               \
 210 } while(0)                                                              \
 211
 212 #define _pcp_protect(operation, pcp, val)                       \
 213 ({                                                              \
 214         typeof(pcp) __retval;                                   \
 215         preempt_disable();                                      \
 216         __retval = (typeof(pcp))operation(raw_cpu_ptr(&(pcp)),  \
 217                                           (val), sizeof(pcp));  \
 218         preempt_enable();                                       \
 219         __retval;                                               \
 220 })
 221
 222 #define _percpu_add(pcp, val) \
 223         _pcp_protect(__percpu_add, pcp, val)
 224
 225 #define _percpu_add_return(pcp, val) _percpu_add(pcp, val)
 226
 227 #define _percpu_and(pcp, val) \
 228         _pcp_protect(__percpu_and, pcp, val)
 229
 230 #define _percpu_or(pcp, val) \
 231         _pcp_protect(__percpu_or, pcp, val)
 232
 233 #define _percpu_xchg(pcp, val) (typeof(pcp)) \
 234         _pcp_protect(__percpu_xchg, pcp, (unsigned long)(val))
 235
 236 #define this_cpu_add_1(pcp, val) _percpu_add(pcp, val)
 237 #define this_cpu_add_2(pcp, val) _percpu_add(pcp, val)
 238 #define this_cpu_add_4(pcp, val) _percpu_add(pcp, val)
 239 #define this_cpu_add_8(pcp, val) _percpu_add(pcp, val)
 240
 241 #define this_cpu_add_return_1(pcp, val) _percpu_add_return(pcp, val)
 242 #define this_cpu_add_return_2(pcp, val) _percpu_add_return(pcp, val)
 243 #define this_cpu_add_return_4(pcp, val) _percpu_add_return(pcp, val)
 244 #define this_cpu_add_return_8(pcp, val) _percpu_add_return(pcp, val)
 245
 246 #define this_cpu_and_1(pcp, val) _percpu_and(pcp, val)
 247 #define this_cpu_and_2(pcp, val) _percpu_and(pcp, val)
 248 #define this_cpu_and_4(pcp, val) _percpu_and(pcp, val)
 249 #define this_cpu_and_8(pcp, val) _percpu_and(pcp, val)
 250
 251 #define this_cpu_or_1(pcp, val) _percpu_or(pcp, val)
 252 #define this_cpu_or_2(pcp, val) _percpu_or(pcp, val)
 253 #define this_cpu_or_4(pcp, val) _percpu_or(pcp, val)
 254 #define this_cpu_or_8(pcp, val) _percpu_or(pcp, val)
 255
 256 #define this_cpu_read_1(pcp) _percpu_read(pcp)
 257 #define this_cpu_read_2(pcp) _percpu_read(pcp)
 258 #define this_cpu_read_4(pcp) _percpu_read(pcp)
 259 #define this_cpu_read_8(pcp) _percpu_read(pcp)
 260
 261 #define this_cpu_write_1(pcp, val) _percpu_write(pcp, val)
 262 #define this_cpu_write_2(pcp, val) _percpu_write(pcp, val)
 263 #define this_cpu_write_4(pcp, val) _percpu_write(pcp, val)
 264 #define this_cpu_write_8(pcp, val) _percpu_write(pcp, val)
 265
 266 #define this_cpu_xchg_1(pcp, val) _percpu_xchg(pcp, val)
 267 #define this_cpu_xchg_2(pcp, val) _percpu_xchg(pcp, val)
 268 #define this_cpu_xchg_4(pcp, val) _percpu_xchg(pcp, val)
 269 #define this_cpu_xchg_8(pcp, val) _percpu_xchg(pcp, val)
 270
 271 #include <asm-generic/percpu.h>
 272
 273 #endif /* __ASM_PERCPU_H */