arch/x86/include/asm/percpu.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_PERCPU_H
   3 #define _ASM_X86_PERCPU_H
   4
   5 #ifdef CONFIG_X86_64
   6 #define __percpu_seg            gs
   7 #else
   8 #define __percpu_seg            fs
   9 #endif
  10
  11 #ifdef __ASSEMBLY__
  12
  13 #ifdef CONFIG_SMP
  14 #define PER_CPU_VAR(var)        %__percpu_seg:var
  15 #else /* ! SMP */
  16 #define PER_CPU_VAR(var)        var
  17 #endif  /* SMP */
  18
  19 #ifdef CONFIG_X86_64_SMP
  20 #define INIT_PER_CPU_VAR(var)  init_per_cpu__##var
  21 #else
  22 #define INIT_PER_CPU_VAR(var)  var
  23 #endif
  24
  25 #else /* ...!ASSEMBLY */
  26
  27 #include <linux/kernel.h>
  28 #include <linux/stringify.h>
  29
  30 #ifdef CONFIG_SMP
  31 #define __percpu_prefix         "%%"__stringify(__percpu_seg)":"
  32 #define __my_cpu_offset         this_cpu_read(this_cpu_off)
  33
  34 /*
  35  * Compared to the generic __my_cpu_offset version, the following
  36  * saves one instruction and avoids clobbering a temp register.
  37  */
  38 #define arch_raw_cpu_ptr(ptr)                           \
  39 ({                                                      \
  40         unsigned long tcp_ptr__;                        \
  41         asm volatile("add " __percpu_arg(1) ", %0"      \
  42                      : "=r" (tcp_ptr__)                 \
  43                      : "m" (this_cpu_off), "0" (ptr));  \
  44         (typeof(*(ptr)) __kernel __force *)tcp_ptr__;   \
  45 })
  46 #else
  47 #define __percpu_prefix         ""
  48 #endif
  49
  50 #define __percpu_arg(x)         __percpu_prefix "%" #x
  51
  52 /*
  53  * Initialized pointers to per-cpu variables needed for the boot
  54  * processor need to use these macros to get the proper address
  55  * offset from __per_cpu_load on SMP.
  56  *
  57  * There also must be an entry in vmlinux_64.lds.S
  58  */
  59 #define DECLARE_INIT_PER_CPU(var) \
  60        extern typeof(var) init_per_cpu_var(var)
  61
  62 #ifdef CONFIG_X86_64_SMP
  63 #define init_per_cpu_var(var)  init_per_cpu__##var
  64 #else
  65 #define init_per_cpu_var(var)  var
  66 #endif
  67
  68 /* For arch-specific code, we can use direct single-insn ops (they
  69  * don't give an lvalue though). */
  70
  71 #define __pcpu_type_1 u8
  72 #define __pcpu_type_2 u16
  73 #define __pcpu_type_4 u32
  74 #define __pcpu_type_8 u64
  75
  76 #define __pcpu_cast_1(val) ((u8)(((unsigned long) val) & 0xff))
  77 #define __pcpu_cast_2(val) ((u16)(((unsigned long) val) & 0xffff))
  78 #define __pcpu_cast_4(val) ((u32)(((unsigned long) val) & 0xffffffff))
  79 #define __pcpu_cast_8(val) ((u64)(val))
  80
  81 #define __pcpu_op1_1(op, dst) op "b " dst
  82 #define __pcpu_op1_2(op, dst) op "w " dst
  83 #define __pcpu_op1_4(op, dst) op "l " dst
  84 #define __pcpu_op1_8(op, dst) op "q " dst
  85
  86 #define __pcpu_op2_1(op, src, dst) op "b " src ", " dst
  87 #define __pcpu_op2_2(op, src, dst) op "w " src ", " dst
  88 #define __pcpu_op2_4(op, src, dst) op "l " src ", " dst
  89 #define __pcpu_op2_8(op, src, dst) op "q " src ", " dst
  90
  91 #define __pcpu_reg_1(mod, x) mod "q" (x)
  92 #define __pcpu_reg_2(mod, x) mod "r" (x)
  93 #define __pcpu_reg_4(mod, x) mod "r" (x)
  94 #define __pcpu_reg_8(mod, x) mod "r" (x)
  95
  96 #define __pcpu_reg_imm_1(x) "qi" (x)
  97 #define __pcpu_reg_imm_2(x) "ri" (x)
  98 #define __pcpu_reg_imm_4(x) "ri" (x)
  99 #define __pcpu_reg_imm_8(x) "re" (x)
 100
 101 #define percpu_to_op(size, qual, op, _var, _val)                        \
 102 do {                                                                    \
 103         __pcpu_type_##size pto_val__ = __pcpu_cast_##size(_val);        \
 104         if (0) {                                                        \
 105                 typeof(_var) pto_tmp__;                                 \
 106                 pto_tmp__ = (_val);                                     \
 107                 (void)pto_tmp__;                                        \
 108         }                                                               \
 109         asm qual(__pcpu_op2_##size(op, "%[val]", __percpu_arg([var]))   \
 110             : [var] "+m" (_var)                                         \
 111             : [val] __pcpu_reg_imm_##size(pto_val__));                  \
 112 } while (0)
 113
 114 #define percpu_unary_op(size, qual, op, _var)                           \
 115 ({                                                                      \
 116         asm qual (__pcpu_op1_##size(op, __percpu_arg([var]))            \
 117             : [var] "+m" (_var));                                       \
 118 })
 119
 120 /*
 121  * Generate a percpu add to memory instruction and optimize code
 122  * if one is added or subtracted.
 123  */
 124 #define percpu_add_op(size, qual, var, val)                             \
 125 do {                                                                    \
 126         const int pao_ID__ = (__builtin_constant_p(val) &&              \
 127                               ((val) == 1 || (val) == -1)) ?            \
 128                                 (int)(val) : 0;                         \
 129         if (0) {                                                        \
 130                 typeof(var) pao_tmp__;                                  \
 131                 pao_tmp__ = (val);                                      \
 132                 (void)pao_tmp__;                                        \
 133         }                                                               \
 134         if (pao_ID__ == 1)                                              \
 135                 percpu_unary_op(size, qual, "inc", var);                \
 136         else if (pao_ID__ == -1)                                        \
 137                 percpu_unary_op(size, qual, "dec", var);                \
 138         else                                                            \
 139                 percpu_to_op(size, qual, "add", var, val);              \
 140 } while (0)
 141
 142 #define percpu_from_op(size, qual, op, _var)                            \
 143 ({                                                                      \
 144         __pcpu_type_##size pfo_val__;                                   \
 145         asm qual (__pcpu_op2_##size(op, __percpu_arg([var]), "%[val]")  \
 146             : [val] __pcpu_reg_##size("=", pfo_val__)                   \
 147             : [var] "m" (_var));                                        \
 148         (typeof(_var))(unsigned long) pfo_val__;                        \
 149 })
 150
 151 #define percpu_stable_op(size, op, _var)                                \
 152 ({                                                                      \
 153         __pcpu_type_##size pfo_val__;                                   \
 154         asm(__pcpu_op2_##size(op, __percpu_arg(P[var]), "%[val]")       \
 155             : [val] __pcpu_reg_##size("=", pfo_val__)                   \
 156             : [var] "p" (&(_var)));                                     \
 157         (typeof(_var))(unsigned long) pfo_val__;                        \
 158 })
 159
 160 /*
 161  * Add return operation
 162  */
 163 #define percpu_add_return_op(size, qual, _var, _val)                    \
 164 ({                                                                      \
 165         __pcpu_type_##size paro_tmp__ = __pcpu_cast_##size(_val);       \
 166         asm qual (__pcpu_op2_##size("xadd", "%[tmp]",                   \
 167                                      __percpu_arg([var]))               \
 168                   : [tmp] __pcpu_reg_##size("+", paro_tmp__),           \
 169                     [var] "+m" (_var)                                   \
 170                   : : "memory");                                        \
 171         (typeof(_var))(unsigned long) (paro_tmp__ + _val);              \
 172 })
 173
 174 /*
 175  * xchg is implemented using cmpxchg without a lock prefix. xchg is
 176  * expensive due to the implied lock prefix.  The processor cannot prefetch
 177  * cachelines if xchg is used.
 178  */
 179 #define percpu_xchg_op(size, qual, _var, _nval)                         \
 180 ({                                                                      \
 181         __pcpu_type_##size pxo_old__;                                   \
 182         __pcpu_type_##size pxo_new__ = __pcpu_cast_##size(_nval);       \
 183         asm qual (__pcpu_op2_##size("mov", __percpu_arg([var]),         \
 184                                     "%[oval]")                          \
 185                   "\n1:\t"                                              \
 186                   __pcpu_op2_##size("cmpxchg", "%[nval]",               \
 187                                     __percpu_arg([var]))                \
 188                   "\n\tjnz 1b"                                          \
 189                   : [oval] "=&a" (pxo_old__),                           \
 190                     [var] "+m" (_var)                                   \
 191                   : [nval] __pcpu_reg_##size(, pxo_new__)               \
 192                   : "memory");                                          \
 193         (typeof(_var))(unsigned long) pxo_old__;                        \
 194 })
 195
 196 /*
 197  * cmpxchg has no such implied lock semantics as a result it is much
 198  * more efficient for cpu local operations.
 199  */
 200 #define percpu_cmpxchg_op(size, qual, _var, _oval, _nval)               \
 201 ({                                                                      \
 202         __pcpu_type_##size pco_old__ = __pcpu_cast_##size(_oval);       \
 203         __pcpu_type_##size pco_new__ = __pcpu_cast_##size(_nval);       \
 204         asm qual (__pcpu_op2_##size("cmpxchg", "%[nval]",               \
 205                                     __percpu_arg([var]))                \
 206                   : [oval] "+a" (pco_old__),                            \
 207                     [var] "+m" (_var)                                   \
 208                   : [nval] __pcpu_reg_##size(, pco_new__)               \
 209                   : "memory");                                          \
 210         (typeof(_var))(unsigned long) pco_old__;                        \
 211 })
 212
 213 /*
 214  * this_cpu_read() makes gcc load the percpu variable every time it is
 215  * accessed while this_cpu_read_stable() allows the value to be cached.
 216  * this_cpu_read_stable() is more efficient and can be used if its value
 217  * is guaranteed to be valid across cpus.  The current users include
 218  * get_current() and get_thread_info() both of which are actually
 219  * per-thread variables implemented as per-cpu variables and thus
 220  * stable for the duration of the respective task.
 221  */
 222 #define this_cpu_read_stable_1(pcp)     percpu_stable_op(1, "mov", pcp)
 223 #define this_cpu_read_stable_2(pcp)     percpu_stable_op(2, "mov", pcp)
 224 #define this_cpu_read_stable_4(pcp)     percpu_stable_op(4, "mov", pcp)
 225 #define this_cpu_read_stable_8(pcp)     percpu_stable_op(8, "mov", pcp)
 226 #define this_cpu_read_stable(pcp)       __pcpu_size_call_return(this_cpu_read_stable_, pcp)
 227
 228 #define raw_cpu_read_1(pcp)             percpu_from_op(1, , "mov", pcp)
 229 #define raw_cpu_read_2(pcp)             percpu_from_op(2, , "mov", pcp)
 230 #define raw_cpu_read_4(pcp)             percpu_from_op(4, , "mov", pcp)
 231
 232 #define raw_cpu_write_1(pcp, val)       percpu_to_op(1, , "mov", (pcp), val)
 233 #define raw_cpu_write_2(pcp, val)       percpu_to_op(2, , "mov", (pcp), val)
 234 #define raw_cpu_write_4(pcp, val)       percpu_to_op(4, , "mov", (pcp), val)
 235 #define raw_cpu_add_1(pcp, val)         percpu_add_op(1, , (pcp), val)
 236 #define raw_cpu_add_2(pcp, val)         percpu_add_op(2, , (pcp), val)
 237 #define raw_cpu_add_4(pcp, val)         percpu_add_op(4, , (pcp), val)
 238 #define raw_cpu_and_1(pcp, val)         percpu_to_op(1, , "and", (pcp), val)
 239 #define raw_cpu_and_2(pcp, val)         percpu_to_op(2, , "and", (pcp), val)
 240 #define raw_cpu_and_4(pcp, val)         percpu_to_op(4, , "and", (pcp), val)
 241 #define raw_cpu_or_1(pcp, val)          percpu_to_op(1, , "or", (pcp), val)
 242 #define raw_cpu_or_2(pcp, val)          percpu_to_op(2, , "or", (pcp), val)
 243 #define raw_cpu_or_4(pcp, val)          percpu_to_op(4, , "or", (pcp), val)
 244
 245 /*
 246  * raw_cpu_xchg() can use a load-store since it is not required to be
 247  * IRQ-safe.
 248  */
 249 #define raw_percpu_xchg_op(var, nval)                                   \
 250 ({                                                                      \
 251         typeof(var) pxo_ret__ = raw_cpu_read(var);                      \
 252         raw_cpu_write(var, (nval));                                     \
 253         pxo_ret__;                                                      \
 254 })
 255
 256 #define raw_cpu_xchg_1(pcp, val)        raw_percpu_xchg_op(pcp, val)
 257 #define raw_cpu_xchg_2(pcp, val)        raw_percpu_xchg_op(pcp, val)
 258 #define raw_cpu_xchg_4(pcp, val)        raw_percpu_xchg_op(pcp, val)
 259
 260 #define this_cpu_read_1(pcp)            percpu_from_op(1, volatile, "mov", pcp)
 261 #define this_cpu_read_2(pcp)            percpu_from_op(2, volatile, "mov", pcp)
 262 #define this_cpu_read_4(pcp)            percpu_from_op(4, volatile, "mov", pcp)
 263 #define this_cpu_write_1(pcp, val)      percpu_to_op(1, volatile, "mov", (pcp), val)
 264 #define this_cpu_write_2(pcp, val)      percpu_to_op(2, volatile, "mov", (pcp), val)
 265 #define this_cpu_write_4(pcp, val)      percpu_to_op(4, volatile, "mov", (pcp), val)
 266 #define this_cpu_add_1(pcp, val)        percpu_add_op(1, volatile, (pcp), val)
 267 #define this_cpu_add_2(pcp, val)        percpu_add_op(2, volatile, (pcp), val)
 268 #define this_cpu_add_4(pcp, val)        percpu_add_op(4, volatile, (pcp), val)
 269 #define this_cpu_and_1(pcp, val)        percpu_to_op(1, volatile, "and", (pcp), val)
 270 #define this_cpu_and_2(pcp, val)        percpu_to_op(2, volatile, "and", (pcp), val)
 271 #define this_cpu_and_4(pcp, val)        percpu_to_op(4, volatile, "and", (pcp), val)
 272 #define this_cpu_or_1(pcp, val)         percpu_to_op(1, volatile, "or", (pcp), val)
 273 #define this_cpu_or_2(pcp, val)         percpu_to_op(2, volatile, "or", (pcp), val)
 274 #define this_cpu_or_4(pcp, val)         percpu_to_op(4, volatile, "or", (pcp), val)
 275 #define this_cpu_xchg_1(pcp, nval)      percpu_xchg_op(1, volatile, pcp, nval)
 276 #define this_cpu_xchg_2(pcp, nval)      percpu_xchg_op(2, volatile, pcp, nval)
 277 #define this_cpu_xchg_4(pcp, nval)      percpu_xchg_op(4, volatile, pcp, nval)
 278
 279 #define raw_cpu_add_return_1(pcp, val)          percpu_add_return_op(1, , pcp, val)
 280 #define raw_cpu_add_return_2(pcp, val)          percpu_add_return_op(2, , pcp, val)
 281 #define raw_cpu_add_return_4(pcp, val)          percpu_add_return_op(4, , pcp, val)
 282 #define raw_cpu_cmpxchg_1(pcp, oval, nval)      percpu_cmpxchg_op(1, , pcp, oval, nval)
 283 #define raw_cpu_cmpxchg_2(pcp, oval, nval)      percpu_cmpxchg_op(2, , pcp, oval, nval)
 284 #define raw_cpu_cmpxchg_4(pcp, oval, nval)      percpu_cmpxchg_op(4, , pcp, oval, nval)
 285
 286 #define this_cpu_add_return_1(pcp, val)         percpu_add_return_op(1, volatile, pcp, val)
 287 #define this_cpu_add_return_2(pcp, val)         percpu_add_return_op(2, volatile, pcp, val)
 288 #define this_cpu_add_return_4(pcp, val)         percpu_add_return_op(4, volatile, pcp, val)
 289 #define this_cpu_cmpxchg_1(pcp, oval, nval)     percpu_cmpxchg_op(1, volatile, pcp, oval, nval)
 290 #define this_cpu_cmpxchg_2(pcp, oval, nval)     percpu_cmpxchg_op(2, volatile, pcp, oval, nval)
 291 #define this_cpu_cmpxchg_4(pcp, oval, nval)     percpu_cmpxchg_op(4, volatile, pcp, oval, nval)
 292
 293 #ifdef CONFIG_X86_CMPXCHG64
 294 #define percpu_cmpxchg8b_double(pcp1, pcp2, o1, o2, n1, n2)             \
 295 ({                                                                      \
 296         bool __ret;                                                     \
 297         typeof(pcp1) __o1 = (o1), __n1 = (n1);                          \
 298         typeof(pcp2) __o2 = (o2), __n2 = (n2);                          \
 299         asm volatile("cmpxchg8b "__percpu_arg(1)                        \
 300                      CC_SET(z)                                          \
 301                      : CC_OUT(z) (__ret), "+m" (pcp1), "+m" (pcp2), "+a" (__o1), "+d" (__o2) \
 302                      : "b" (__n1), "c" (__n2));                         \
 303         __ret;                                                          \
 304 })
 305
 306 #define raw_cpu_cmpxchg_double_4        percpu_cmpxchg8b_double
 307 #define this_cpu_cmpxchg_double_4       percpu_cmpxchg8b_double
 308 #endif /* CONFIG_X86_CMPXCHG64 */
 309
 310 /*
 311  * Per cpu atomic 64 bit operations are only available under 64 bit.
 312  * 32 bit must fall back to generic operations.
 313  */
 314 #ifdef CONFIG_X86_64
 315 #define raw_cpu_read_8(pcp)                     percpu_from_op(8, , "mov", pcp)
 316 #define raw_cpu_write_8(pcp, val)               percpu_to_op(8, , "mov", (pcp), val)
 317 #define raw_cpu_add_8(pcp, val)                 percpu_add_op(8, , (pcp), val)
 318 #define raw_cpu_and_8(pcp, val)                 percpu_to_op(8, , "and", (pcp), val)
 319 #define raw_cpu_or_8(pcp, val)                  percpu_to_op(8, , "or", (pcp), val)
 320 #define raw_cpu_add_return_8(pcp, val)          percpu_add_return_op(8, , pcp, val)
 321 #define raw_cpu_xchg_8(pcp, nval)               raw_percpu_xchg_op(pcp, nval)
 322 #define raw_cpu_cmpxchg_8(pcp, oval, nval)      percpu_cmpxchg_op(8, , pcp, oval, nval)
 323
 324 #define this_cpu_read_8(pcp)                    percpu_from_op(8, volatile, "mov", pcp)
 325 #define this_cpu_write_8(pcp, val)              percpu_to_op(8, volatile, "mov", (pcp), val)
 326 #define this_cpu_add_8(pcp, val)                percpu_add_op(8, volatile, (pcp), val)
 327 #define this_cpu_and_8(pcp, val)                percpu_to_op(8, volatile, "and", (pcp), val)
 328 #define this_cpu_or_8(pcp, val)                 percpu_to_op(8, volatile, "or", (pcp), val)
 329 #define this_cpu_add_return_8(pcp, val)         percpu_add_return_op(8, volatile, pcp, val)
 330 #define this_cpu_xchg_8(pcp, nval)              percpu_xchg_op(8, volatile, pcp, nval)
 331 #define this_cpu_cmpxchg_8(pcp, oval, nval)     percpu_cmpxchg_op(8, volatile, pcp, oval, nval)
 332
 333 /*
 334  * Pretty complex macro to generate cmpxchg16 instruction.  The instruction
 335  * is not supported on early AMD64 processors so we must be able to emulate
 336  * it in software.  The address used in the cmpxchg16 instruction must be
 337  * aligned to a 16 byte boundary.
 338  */
 339 #define percpu_cmpxchg16b_double(pcp1, pcp2, o1, o2, n1, n2)            \
 340 ({                                                                      \
 341         bool __ret;                                                     \
 342         typeof(pcp1) __o1 = (o1), __n1 = (n1);                          \
 343         typeof(pcp2) __o2 = (o2), __n2 = (n2);                          \
 344         alternative_io("leaq %P1,%%rsi\n\tcall this_cpu_cmpxchg16b_emu\n\t", \
 345                        "cmpxchg16b " __percpu_arg(1) "\n\tsetz %0\n\t", \
 346                        X86_FEATURE_CX16,                                \
 347                        ASM_OUTPUT2("=a" (__ret), "+m" (pcp1),           \
 348                                    "+m" (pcp2), "+d" (__o2)),           \
 349                        "b" (__n1), "c" (__n2), "a" (__o1) : "rsi");     \
 350         __ret;                                                          \
 351 })
 352
 353 #define raw_cpu_cmpxchg_double_8        percpu_cmpxchg16b_double
 354 #define this_cpu_cmpxchg_double_8       percpu_cmpxchg16b_double
 355
 356 #endif
 357
 358 static __always_inline bool x86_this_cpu_constant_test_bit(unsigned int nr,
 359                         const unsigned long __percpu *addr)
 360 {
 361         unsigned long __percpu *a =
 362                 (unsigned long __percpu *)addr + nr / BITS_PER_LONG;
 363
 364 #ifdef CONFIG_X86_64
 365         return ((1UL << (nr % BITS_PER_LONG)) & raw_cpu_read_8(*a)) != 0;
 366 #else
 367         return ((1UL << (nr % BITS_PER_LONG)) & raw_cpu_read_4(*a)) != 0;
 368 #endif
 369 }
 370
 371 static inline bool x86_this_cpu_variable_test_bit(int nr,
 372                         const unsigned long __percpu *addr)
 373 {
 374         bool oldbit;
 375
 376         asm volatile("btl "__percpu_arg(2)",%1"
 377                         CC_SET(c)
 378                         : CC_OUT(c) (oldbit)
 379                         : "m" (*(unsigned long __percpu *)addr), "Ir" (nr));
 380
 381         return oldbit;
 382 }
 383
 384 #define x86_this_cpu_test_bit(nr, addr)                 \
 385         (__builtin_constant_p((nr))                     \
 386          ? x86_this_cpu_constant_test_bit((nr), (addr)) \
 387          : x86_this_cpu_variable_test_bit((nr), (addr)))
 388
 389
 390 #include <asm-generic/percpu.h>
 391
 392 /* We can use this directly for local CPU (faster). */
 393 DECLARE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off);
 394
 395 #endif /* !__ASSEMBLY__ */
 396
 397 #ifdef CONFIG_SMP
 398
 399 /*
 400  * Define the "EARLY_PER_CPU" macros.  These are used for some per_cpu
 401  * variables that are initialized and accessed before there are per_cpu
 402  * areas allocated.
 403  */
 404
 405 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)                  \
 406         DEFINE_PER_CPU(_type, _name) = _initvalue;                      \
 407         __typeof__(_type) _name##_early_map[NR_CPUS] __initdata =       \
 408                                 { [0 ... NR_CPUS-1] = _initvalue };     \
 409         __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
 410
 411 #define DEFINE_EARLY_PER_CPU_READ_MOSTLY(_type, _name, _initvalue)      \
 412         DEFINE_PER_CPU_READ_MOSTLY(_type, _name) = _initvalue;          \
 413         __typeof__(_type) _name##_early_map[NR_CPUS] __initdata =       \
 414                                 { [0 ... NR_CPUS-1] = _initvalue };     \
 415         __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
 416
 417 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 418         EXPORT_PER_CPU_SYMBOL(_name)
 419
 420 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 421         DECLARE_PER_CPU(_type, _name);                          \
 422         extern __typeof__(_type) *_name##_early_ptr;            \
 423         extern __typeof__(_type)  _name##_early_map[]
 424
 425 #define DECLARE_EARLY_PER_CPU_READ_MOSTLY(_type, _name)         \
 426         DECLARE_PER_CPU_READ_MOSTLY(_type, _name);              \
 427         extern __typeof__(_type) *_name##_early_ptr;            \
 428         extern __typeof__(_type)  _name##_early_map[]
 429
 430 #define early_per_cpu_ptr(_name) (_name##_early_ptr)
 431 #define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
 432 #define early_per_cpu(_name, _cpu)                              \
 433         *(early_per_cpu_ptr(_name) ?                            \
 434                 &early_per_cpu_ptr(_name)[_cpu] :               \
 435                 &per_cpu(_name, _cpu))
 436
 437 #else   /* !CONFIG_SMP */
 438 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)          \
 439         DEFINE_PER_CPU(_type, _name) = _initvalue
 440
 441 #define DEFINE_EARLY_PER_CPU_READ_MOSTLY(_type, _name, _initvalue)      \
 442         DEFINE_PER_CPU_READ_MOSTLY(_type, _name) = _initvalue
 443
 444 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 445         EXPORT_PER_CPU_SYMBOL(_name)
 446
 447 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 448         DECLARE_PER_CPU(_type, _name)
 449
 450 #define DECLARE_EARLY_PER_CPU_READ_MOSTLY(_type, _name)         \
 451         DECLARE_PER_CPU_READ_MOSTLY(_type, _name)
 452
 453 #define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
 454 #define early_per_cpu_ptr(_name) NULL
 455 /* no early_per_cpu_map() */
 456
 457 #endif  /* !CONFIG_SMP */
 458
 459 #endif /* _ASM_X86_PERCPU_H */