arch/x86/include/asm/percpu.h

   1 #ifndef _ASM_X86_PERCPU_H
   2 #define _ASM_X86_PERCPU_H
   3
   4 #ifdef CONFIG_X86_64
   5 #define __percpu_seg            gs
   6 #define __percpu_mov_op         movq
   7 #else
   8 #define __percpu_seg            fs
   9 #define __percpu_mov_op         movl
  10 #endif
  11
  12 #ifdef __ASSEMBLY__
  13
  14 /*
  15  * PER_CPU finds an address of a per-cpu variable.
  16  *
  17  * Args:
  18  *    var - variable name
  19  *    reg - 32bit register
  20  *
  21  * The resulting address is stored in the "reg" argument.
  22  *
  23  * Example:
  24  *    PER_CPU(cpu_gdt_descr, %ebx)
  25  */
  26 #ifdef CONFIG_SMP
  27 #define PER_CPU(var, reg)                                               \
  28         __percpu_mov_op %__percpu_seg:this_cpu_off, reg;                \
  29         lea var(reg), reg
  30 #define PER_CPU_VAR(var)        %__percpu_seg:var
  31 #else /* ! SMP */
  32 #define PER_CPU(var, reg)       __percpu_mov_op $var, reg
  33 #define PER_CPU_VAR(var)        var
  34 #endif  /* SMP */
  35
  36 #ifdef CONFIG_X86_64_SMP
  37 #define INIT_PER_CPU_VAR(var)  init_per_cpu__##var
  38 #else
  39 #define INIT_PER_CPU_VAR(var)  var
  40 #endif
  41
  42 #else /* ...!ASSEMBLY */
  43
  44 #include <linux/kernel.h>
  45 #include <linux/stringify.h>
  46
  47 #ifdef CONFIG_SMP
  48 #define __percpu_arg(x)         "%%"__stringify(__percpu_seg)":%P" #x
  49 #define __my_cpu_offset         percpu_read(this_cpu_off)
  50 #else
  51 #define __percpu_arg(x)         "%P" #x
  52 #endif
  53
  54 /*
  55  * Initialized pointers to per-cpu variables needed for the boot
  56  * processor need to use these macros to get the proper address
  57  * offset from __per_cpu_load on SMP.
  58  *
  59  * There also must be an entry in vmlinux_64.lds.S
  60  */
  61 #define DECLARE_INIT_PER_CPU(var) \
  62        extern typeof(var) init_per_cpu_var(var)
  63
  64 #ifdef CONFIG_X86_64_SMP
  65 #define init_per_cpu_var(var)  init_per_cpu__##var
  66 #else
  67 #define init_per_cpu_var(var)  var
  68 #endif
  69
  70 /* For arch-specific code, we can use direct single-insn ops (they
  71  * don't give an lvalue though). */
  72 extern void __bad_percpu_size(void);
  73
  74 #define percpu_to_op(op, var, val)                      \
  75 do {                                                    \
  76         typedef typeof(var) pto_T__;                    \
  77         if (0) {                                        \
  78                 pto_T__ pto_tmp__;                      \
  79                 pto_tmp__ = (val);                      \
  80         }                                               \
  81         switch (sizeof(var)) {                          \
  82         case 1:                                         \
  83                 asm(op "b %1,"__percpu_arg(0)           \
  84                     : "+m" (var)                        \
  85                     : "qi" ((pto_T__)(val)));           \
  86                 break;                                  \
  87         case 2:                                         \
  88                 asm(op "w %1,"__percpu_arg(0)           \
  89                     : "+m" (var)                        \
  90                     : "ri" ((pto_T__)(val)));           \
  91                 break;                                  \
  92         case 4:                                         \
  93                 asm(op "l %1,"__percpu_arg(0)           \
  94                     : "+m" (var)                        \
  95                     : "ri" ((pto_T__)(val)));           \
  96                 break;                                  \
  97         case 8:                                         \
  98                 asm(op "q %1,"__percpu_arg(0)           \
  99                     : "+m" (var)                        \
 100                     : "re" ((pto_T__)(val)));           \
 101                 break;                                  \
 102         default: __bad_percpu_size();                   \
 103         }                                               \
 104 } while (0)
 105
 106 /*
 107  * Generate a percpu add to memory instruction and optimize code
 108  * if a one is added or subtracted.
 109  */
 110 #define percpu_add_op(var, val)                                         \
 111 do {                                                                    \
 112         typedef typeof(var) pao_T__;                                    \
 113         const int pao_ID__ = (__builtin_constant_p(val) &&              \
 114                               ((val) == 1 || (val) == -1)) ? (val) : 0; \
 115         if (0) {                                                        \
 116                 pao_T__ pao_tmp__;                                      \
 117                 pao_tmp__ = (val);                                      \
 118         }                                                               \
 119         switch (sizeof(var)) {                                          \
 120         case 1:                                                         \
 121                 if (pao_ID__ == 1)                                      \
 122                         asm("incb "__percpu_arg(0) : "+m" (var));       \
 123                 else if (pao_ID__ == -1)                                \
 124                         asm("decb "__percpu_arg(0) : "+m" (var));       \
 125                 else                                                    \
 126                         asm("addb %1, "__percpu_arg(0)                  \
 127                             : "+m" (var)                                \
 128                             : "qi" ((pao_T__)(val)));                   \
 129                 break;                                                  \
 130         case 2:                                                         \
 131                 if (pao_ID__ == 1)                                      \
 132                         asm("incw "__percpu_arg(0) : "+m" (var));       \
 133                 else if (pao_ID__ == -1)                                \
 134                         asm("decw "__percpu_arg(0) : "+m" (var));       \
 135                 else                                                    \
 136                         asm("addw %1, "__percpu_arg(0)                  \
 137                             : "+m" (var)                                \
 138                             : "ri" ((pao_T__)(val)));                   \
 139                 break;                                                  \
 140         case 4:                                                         \
 141                 if (pao_ID__ == 1)                                      \
 142                         asm("incl "__percpu_arg(0) : "+m" (var));       \
 143                 else if (pao_ID__ == -1)                                \
 144                         asm("decl "__percpu_arg(0) : "+m" (var));       \
 145                 else                                                    \
 146                         asm("addl %1, "__percpu_arg(0)                  \
 147                             : "+m" (var)                                \
 148                             : "ri" ((pao_T__)(val)));                   \
 149                 break;                                                  \
 150         case 8:                                                         \
 151                 if (pao_ID__ == 1)                                      \
 152                         asm("incq "__percpu_arg(0) : "+m" (var));       \
 153                 else if (pao_ID__ == -1)                                \
 154                         asm("decq "__percpu_arg(0) : "+m" (var));       \
 155                 else                                                    \
 156                         asm("addq %1, "__percpu_arg(0)                  \
 157                             : "+m" (var)                                \
 158                             : "re" ((pao_T__)(val)));                   \
 159                 break;                                                  \
 160         default: __bad_percpu_size();                                   \
 161         }                                                               \
 162 } while (0)
 163
 164 #define percpu_from_op(op, var, constraint)             \
 165 ({                                                      \
 166         typeof(var) pfo_ret__;                          \
 167         switch (sizeof(var)) {                          \
 168         case 1:                                         \
 169                 asm(op "b "__percpu_arg(1)",%0"         \
 170                     : "=q" (pfo_ret__)                  \
 171                     : constraint);                      \
 172                 break;                                  \
 173         case 2:                                         \
 174                 asm(op "w "__percpu_arg(1)",%0"         \
 175                     : "=r" (pfo_ret__)                  \
 176                     : constraint);                      \
 177                 break;                                  \
 178         case 4:                                         \
 179                 asm(op "l "__percpu_arg(1)",%0"         \
 180                     : "=r" (pfo_ret__)                  \
 181                     : constraint);                      \
 182                 break;                                  \
 183         case 8:                                         \
 184                 asm(op "q "__percpu_arg(1)",%0"         \
 185                     : "=r" (pfo_ret__)                  \
 186                     : constraint);                      \
 187                 break;                                  \
 188         default: __bad_percpu_size();                   \
 189         }                                               \
 190         pfo_ret__;                                      \
 191 })
 192
 193 /*
 194  * percpu_read() makes gcc load the percpu variable every time it is
 195  * accessed while percpu_read_stable() allows the value to be cached.
 196  * percpu_read_stable() is more efficient and can be used if its value
 197  * is guaranteed to be valid across cpus.  The current users include
 198  * get_current() and get_thread_info() both of which are actually
 199  * per-thread variables implemented as per-cpu variables and thus
 200  * stable for the duration of the respective task.
 201  */
 202 #define percpu_read(var)                percpu_from_op("mov", var, "m" (var))
 203 #define percpu_read_stable(var)         percpu_from_op("mov", var, "p" (&(var)))
 204 #define percpu_write(var, val)          percpu_to_op("mov", var, val)
 205 #define percpu_add(var, val)            percpu_add_op(var, val)
 206 #define percpu_sub(var, val)            percpu_add_op(var, -(val))
 207 #define percpu_and(var, val)            percpu_to_op("and", var, val)
 208 #define percpu_or(var, val)             percpu_to_op("or", var, val)
 209 #define percpu_xor(var, val)            percpu_to_op("xor", var, val)
 210
 211 #define __this_cpu_read_1(pcp)          percpu_from_op("mov", (pcp), "m"(pcp))
 212 #define __this_cpu_read_2(pcp)          percpu_from_op("mov", (pcp), "m"(pcp))
 213 #define __this_cpu_read_4(pcp)          percpu_from_op("mov", (pcp), "m"(pcp))
 214
 215 #define __this_cpu_write_1(pcp, val)    percpu_to_op("mov", (pcp), val)
 216 #define __this_cpu_write_2(pcp, val)    percpu_to_op("mov", (pcp), val)
 217 #define __this_cpu_write_4(pcp, val)    percpu_to_op("mov", (pcp), val)
 218 #define __this_cpu_add_1(pcp, val)      percpu_add_op((pcp), val)
 219 #define __this_cpu_add_2(pcp, val)      percpu_add_op((pcp), val)
 220 #define __this_cpu_add_4(pcp, val)      percpu_add_op((pcp), val)
 221 #define __this_cpu_and_1(pcp, val)      percpu_to_op("and", (pcp), val)
 222 #define __this_cpu_and_2(pcp, val)      percpu_to_op("and", (pcp), val)
 223 #define __this_cpu_and_4(pcp, val)      percpu_to_op("and", (pcp), val)
 224 #define __this_cpu_or_1(pcp, val)       percpu_to_op("or", (pcp), val)
 225 #define __this_cpu_or_2(pcp, val)       percpu_to_op("or", (pcp), val)
 226 #define __this_cpu_or_4(pcp, val)       percpu_to_op("or", (pcp), val)
 227 #define __this_cpu_xor_1(pcp, val)      percpu_to_op("xor", (pcp), val)
 228 #define __this_cpu_xor_2(pcp, val)      percpu_to_op("xor", (pcp), val)
 229 #define __this_cpu_xor_4(pcp, val)      percpu_to_op("xor", (pcp), val)
 230
 231 #define this_cpu_read_1(pcp)            percpu_from_op("mov", (pcp), "m"(pcp))
 232 #define this_cpu_read_2(pcp)            percpu_from_op("mov", (pcp), "m"(pcp))
 233 #define this_cpu_read_4(pcp)            percpu_from_op("mov", (pcp), "m"(pcp))
 234 #define this_cpu_write_1(pcp, val)      percpu_to_op("mov", (pcp), val)
 235 #define this_cpu_write_2(pcp, val)      percpu_to_op("mov", (pcp), val)
 236 #define this_cpu_write_4(pcp, val)      percpu_to_op("mov", (pcp), val)
 237 #define this_cpu_add_1(pcp, val)        percpu_add_op((pcp), val)
 238 #define this_cpu_add_2(pcp, val)        percpu_add_op((pcp), val)
 239 #define this_cpu_add_4(pcp, val)        percpu_add_op((pcp), val)
 240 #define this_cpu_and_1(pcp, val)        percpu_to_op("and", (pcp), val)
 241 #define this_cpu_and_2(pcp, val)        percpu_to_op("and", (pcp), val)
 242 #define this_cpu_and_4(pcp, val)        percpu_to_op("and", (pcp), val)
 243 #define this_cpu_or_1(pcp, val)         percpu_to_op("or", (pcp), val)
 244 #define this_cpu_or_2(pcp, val)         percpu_to_op("or", (pcp), val)
 245 #define this_cpu_or_4(pcp, val)         percpu_to_op("or", (pcp), val)
 246 #define this_cpu_xor_1(pcp, val)        percpu_to_op("xor", (pcp), val)
 247 #define this_cpu_xor_2(pcp, val)        percpu_to_op("xor", (pcp), val)
 248 #define this_cpu_xor_4(pcp, val)        percpu_to_op("xor", (pcp), val)
 249
 250 #define irqsafe_cpu_add_1(pcp, val)     percpu_add_op((pcp), val)
 251 #define irqsafe_cpu_add_2(pcp, val)     percpu_add_op((pcp), val)
 252 #define irqsafe_cpu_add_4(pcp, val)     percpu_add_op((pcp), val)
 253 #define irqsafe_cpu_and_1(pcp, val)     percpu_to_op("and", (pcp), val)
 254 #define irqsafe_cpu_and_2(pcp, val)     percpu_to_op("and", (pcp), val)
 255 #define irqsafe_cpu_and_4(pcp, val)     percpu_to_op("and", (pcp), val)
 256 #define irqsafe_cpu_or_1(pcp, val)      percpu_to_op("or", (pcp), val)
 257 #define irqsafe_cpu_or_2(pcp, val)      percpu_to_op("or", (pcp), val)
 258 #define irqsafe_cpu_or_4(pcp, val)      percpu_to_op("or", (pcp), val)
 259 #define irqsafe_cpu_xor_1(pcp, val)     percpu_to_op("xor", (pcp), val)
 260 #define irqsafe_cpu_xor_2(pcp, val)     percpu_to_op("xor", (pcp), val)
 261 #define irqsafe_cpu_xor_4(pcp, val)     percpu_to_op("xor", (pcp), val)
 262
 263 /*
 264  * Per cpu atomic 64 bit operations are only available under 64 bit.
 265  * 32 bit must fall back to generic operations.
 266  */
 267 #ifdef CONFIG_X86_64
 268 #define __this_cpu_read_8(pcp)          percpu_from_op("mov", (pcp), "m"(pcp))
 269 #define __this_cpu_write_8(pcp, val)    percpu_to_op("mov", (pcp), val)
 270 #define __this_cpu_add_8(pcp, val)      percpu_add_op((pcp), val)
 271 #define __this_cpu_and_8(pcp, val)      percpu_to_op("and", (pcp), val)
 272 #define __this_cpu_or_8(pcp, val)       percpu_to_op("or", (pcp), val)
 273 #define __this_cpu_xor_8(pcp, val)      percpu_to_op("xor", (pcp), val)
 274
 275 #define this_cpu_read_8(pcp)            percpu_from_op("mov", (pcp), "m"(pcp))
 276 #define this_cpu_write_8(pcp, val)      percpu_to_op("mov", (pcp), val)
 277 #define this_cpu_add_8(pcp, val)        percpu_add_op((pcp), val)
 278 #define this_cpu_and_8(pcp, val)        percpu_to_op("and", (pcp), val)
 279 #define this_cpu_or_8(pcp, val)         percpu_to_op("or", (pcp), val)
 280 #define this_cpu_xor_8(pcp, val)        percpu_to_op("xor", (pcp), val)
 281
 282 #define irqsafe_cpu_add_8(pcp, val)     percpu_add_op((pcp), val)
 283 #define irqsafe_cpu_and_8(pcp, val)     percpu_to_op("and", (pcp), val)
 284 #define irqsafe_cpu_or_8(pcp, val)      percpu_to_op("or", (pcp), val)
 285 #define irqsafe_cpu_xor_8(pcp, val)     percpu_to_op("xor", (pcp), val)
 286
 287 #endif
 288
 289 /* This is not atomic against other CPUs -- CPU preemption needs to be off */
 290 #define x86_test_and_clear_bit_percpu(bit, var)                         \
 291 ({                                                                      \
 292         int old__;                                                      \
 293         asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0"           \
 294                      : "=r" (old__), "+m" (var)                         \
 295                      : "dIr" (bit));                                    \
 296         old__;                                                          \
 297 })
 298
 299 #include <asm-generic/percpu.h>
 300
 301 /* We can use this directly for local CPU (faster). */
 302 DECLARE_PER_CPU(unsigned long, this_cpu_off);
 303
 304 #endif /* !__ASSEMBLY__ */
 305
 306 #ifdef CONFIG_SMP
 307
 308 /*
 309  * Define the "EARLY_PER_CPU" macros.  These are used for some per_cpu
 310  * variables that are initialized and accessed before there are per_cpu
 311  * areas allocated.
 312  */
 313
 314 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)                  \
 315         DEFINE_PER_CPU(_type, _name) = _initvalue;                      \
 316         __typeof__(_type) _name##_early_map[NR_CPUS] __initdata =       \
 317                                 { [0 ... NR_CPUS-1] = _initvalue };     \
 318         __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
 319
 320 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 321         EXPORT_PER_CPU_SYMBOL(_name)
 322
 323 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 324         DECLARE_PER_CPU(_type, _name);                          \
 325         extern __typeof__(_type) *_name##_early_ptr;            \
 326         extern __typeof__(_type)  _name##_early_map[]
 327
 328 #define early_per_cpu_ptr(_name) (_name##_early_ptr)
 329 #define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
 330 #define early_per_cpu(_name, _cpu)                              \
 331         *(early_per_cpu_ptr(_name) ?                            \
 332                 &early_per_cpu_ptr(_name)[_cpu] :               \
 333                 &per_cpu(_name, _cpu))
 334
 335 #else   /* !CONFIG_SMP */
 336 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)          \
 337         DEFINE_PER_CPU(_type, _name) = _initvalue
 338
 339 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 340         EXPORT_PER_CPU_SYMBOL(_name)
 341
 342 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 343         DECLARE_PER_CPU(_type, _name)
 344
 345 #define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
 346 #define early_per_cpu_ptr(_name) NULL
 347 /* no early_per_cpu_map() */
 348
 349 #endif  /* !CONFIG_SMP */
 350
 351 #endif /* _ASM_X86_PERCPU_H */