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
  51 /*
  52  * Compared to the generic __my_cpu_offset version, the following
  53  * saves one instruction and avoids clobbering a temp register.
  54  */
  55 #define __this_cpu_ptr(ptr)                             \
  56 ({                                                      \
  57         unsigned long tcp_ptr__;                        \
  58         __verify_pcpu_ptr(ptr);                         \
  59         asm volatile("add " __percpu_arg(1) ", %0"      \
  60                      : "=r" (tcp_ptr__)                 \
  61                      : "m" (this_cpu_off), "0" (ptr));  \
  62         (typeof(*(ptr)) __kernel __force *)tcp_ptr__;   \
  63 })
  64 #else
  65 #define __percpu_arg(x)         "%P" #x
  66 #endif
  67
  68 /*
  69  * Initialized pointers to per-cpu variables needed for the boot
  70  * processor need to use these macros to get the proper address
  71  * offset from __per_cpu_load on SMP.
  72  *
  73  * There also must be an entry in vmlinux_64.lds.S
  74  */
  75 #define DECLARE_INIT_PER_CPU(var) \
  76        extern typeof(var) init_per_cpu_var(var)
  77
  78 #ifdef CONFIG_X86_64_SMP
  79 #define init_per_cpu_var(var)  init_per_cpu__##var
  80 #else
  81 #define init_per_cpu_var(var)  var
  82 #endif
  83
  84 /* For arch-specific code, we can use direct single-insn ops (they
  85  * don't give an lvalue though). */
  86 extern void __bad_percpu_size(void);
  87
  88 #define percpu_to_op(op, var, val)                      \
  89 do {                                                    \
  90         typedef typeof(var) pto_T__;                    \
  91         if (0) {                                        \
  92                 pto_T__ pto_tmp__;                      \
  93                 pto_tmp__ = (val);                      \
  94                 (void)pto_tmp__;                        \
  95         }                                               \
  96         switch (sizeof(var)) {                          \
  97         case 1:                                         \
  98                 asm(op "b %1,"__percpu_arg(0)           \
  99                     : "+m" (var)                        \
 100                     : "qi" ((pto_T__)(val)));           \
 101                 break;                                  \
 102         case 2:                                         \
 103                 asm(op "w %1,"__percpu_arg(0)           \
 104                     : "+m" (var)                        \
 105                     : "ri" ((pto_T__)(val)));           \
 106                 break;                                  \
 107         case 4:                                         \
 108                 asm(op "l %1,"__percpu_arg(0)           \
 109                     : "+m" (var)                        \
 110                     : "ri" ((pto_T__)(val)));           \
 111                 break;                                  \
 112         case 8:                                         \
 113                 asm(op "q %1,"__percpu_arg(0)           \
 114                     : "+m" (var)                        \
 115                     : "re" ((pto_T__)(val)));           \
 116                 break;                                  \
 117         default: __bad_percpu_size();                   \
 118         }                                               \
 119 } while (0)
 120
 121 /*
 122  * Generate a percpu add to memory instruction and optimize code
 123  * if one is added or subtracted.
 124  */
 125 #define percpu_add_op(var, val)                                         \
 126 do {                                                                    \
 127         typedef typeof(var) pao_T__;                                    \
 128         const int pao_ID__ = (__builtin_constant_p(val) &&              \
 129                               ((val) == 1 || (val) == -1)) ? (val) : 0; \
 130         if (0) {                                                        \
 131                 pao_T__ pao_tmp__;                                      \
 132                 pao_tmp__ = (val);                                      \
 133                 (void)pao_tmp__;                                        \
 134         }                                                               \
 135         switch (sizeof(var)) {                                          \
 136         case 1:                                                         \
 137                 if (pao_ID__ == 1)                                      \
 138                         asm("incb "__percpu_arg(0) : "+m" (var));       \
 139                 else if (pao_ID__ == -1)                                \
 140                         asm("decb "__percpu_arg(0) : "+m" (var));       \
 141                 else                                                    \
 142                         asm("addb %1, "__percpu_arg(0)                  \
 143                             : "+m" (var)                                \
 144                             : "qi" ((pao_T__)(val)));                   \
 145                 break;                                                  \
 146         case 2:                                                         \
 147                 if (pao_ID__ == 1)                                      \
 148                         asm("incw "__percpu_arg(0) : "+m" (var));       \
 149                 else if (pao_ID__ == -1)                                \
 150                         asm("decw "__percpu_arg(0) : "+m" (var));       \
 151                 else                                                    \
 152                         asm("addw %1, "__percpu_arg(0)                  \
 153                             : "+m" (var)                                \
 154                             : "ri" ((pao_T__)(val)));                   \
 155                 break;                                                  \
 156         case 4:                                                         \
 157                 if (pao_ID__ == 1)                                      \
 158                         asm("incl "__percpu_arg(0) : "+m" (var));       \
 159                 else if (pao_ID__ == -1)                                \
 160                         asm("decl "__percpu_arg(0) : "+m" (var));       \
 161                 else                                                    \
 162                         asm("addl %1, "__percpu_arg(0)                  \
 163                             : "+m" (var)                                \
 164                             : "ri" ((pao_T__)(val)));                   \
 165                 break;                                                  \
 166         case 8:                                                         \
 167                 if (pao_ID__ == 1)                                      \
 168                         asm("incq "__percpu_arg(0) : "+m" (var));       \
 169                 else if (pao_ID__ == -1)                                \
 170                         asm("decq "__percpu_arg(0) : "+m" (var));       \
 171                 else                                                    \
 172                         asm("addq %1, "__percpu_arg(0)                  \
 173                             : "+m" (var)                                \
 174                             : "re" ((pao_T__)(val)));                   \
 175                 break;                                                  \
 176         default: __bad_percpu_size();                                   \
 177         }                                                               \
 178 } while (0)
 179
 180 #define percpu_from_op(op, var, constraint)             \
 181 ({                                                      \
 182         typeof(var) pfo_ret__;                          \
 183         switch (sizeof(var)) {                          \
 184         case 1:                                         \
 185                 asm(op "b "__percpu_arg(1)",%0"         \
 186                     : "=q" (pfo_ret__)                  \
 187                     : constraint);                      \
 188                 break;                                  \
 189         case 2:                                         \
 190                 asm(op "w "__percpu_arg(1)",%0"         \
 191                     : "=r" (pfo_ret__)                  \
 192                     : constraint);                      \
 193                 break;                                  \
 194         case 4:                                         \
 195                 asm(op "l "__percpu_arg(1)",%0"         \
 196                     : "=r" (pfo_ret__)                  \
 197                     : constraint);                      \
 198                 break;                                  \
 199         case 8:                                         \
 200                 asm(op "q "__percpu_arg(1)",%0"         \
 201                     : "=r" (pfo_ret__)                  \
 202                     : constraint);                      \
 203                 break;                                  \
 204         default: __bad_percpu_size();                   \
 205         }                                               \
 206         pfo_ret__;                                      \
 207 })
 208
 209 #define percpu_unary_op(op, var)                        \
 210 ({                                                      \
 211         switch (sizeof(var)) {                          \
 212         case 1:                                         \
 213                 asm(op "b "__percpu_arg(0)              \
 214                     : "+m" (var));                      \
 215                 break;                                  \
 216         case 2:                                         \
 217                 asm(op "w "__percpu_arg(0)              \
 218                     : "+m" (var));                      \
 219                 break;                                  \
 220         case 4:                                         \
 221                 asm(op "l "__percpu_arg(0)              \
 222                     : "+m" (var));                      \
 223                 break;                                  \
 224         case 8:                                         \
 225                 asm(op "q "__percpu_arg(0)              \
 226                     : "+m" (var));                      \
 227                 break;                                  \
 228         default: __bad_percpu_size();                   \
 229         }                                               \
 230 })
 231
 232 /*
 233  * percpu_read() makes gcc load the percpu variable every time it is
 234  * accessed while percpu_read_stable() allows the value to be cached.
 235  * percpu_read_stable() is more efficient and can be used if its value
 236  * is guaranteed to be valid across cpus.  The current users include
 237  * get_current() and get_thread_info() both of which are actually
 238  * per-thread variables implemented as per-cpu variables and thus
 239  * stable for the duration of the respective task.
 240  */
 241 #define percpu_read(var)                percpu_from_op("mov", var, "m" (var))
 242 #define percpu_read_stable(var)         percpu_from_op("mov", var, "p" (&(var)))
 243 #define percpu_write(var, val)          percpu_to_op("mov", var, val)
 244 #define percpu_add(var, val)            percpu_add_op(var, val)
 245 #define percpu_sub(var, val)            percpu_add_op(var, -(val))
 246 #define percpu_and(var, val)            percpu_to_op("and", var, val)
 247 #define percpu_or(var, val)             percpu_to_op("or", var, val)
 248 #define percpu_xor(var, val)            percpu_to_op("xor", var, val)
 249 #define percpu_inc(var)         percpu_unary_op("inc", var)
 250
 251 #define __this_cpu_read_1(pcp)          percpu_from_op("mov", (pcp), "m"(pcp))
 252 #define __this_cpu_read_2(pcp)          percpu_from_op("mov", (pcp), "m"(pcp))
 253 #define __this_cpu_read_4(pcp)          percpu_from_op("mov", (pcp), "m"(pcp))
 254
 255 #define __this_cpu_write_1(pcp, val)    percpu_to_op("mov", (pcp), val)
 256 #define __this_cpu_write_2(pcp, val)    percpu_to_op("mov", (pcp), val)
 257 #define __this_cpu_write_4(pcp, val)    percpu_to_op("mov", (pcp), val)
 258 #define __this_cpu_add_1(pcp, val)      percpu_add_op((pcp), val)
 259 #define __this_cpu_add_2(pcp, val)      percpu_add_op((pcp), val)
 260 #define __this_cpu_add_4(pcp, val)      percpu_add_op((pcp), val)
 261 #define __this_cpu_and_1(pcp, val)      percpu_to_op("and", (pcp), val)
 262 #define __this_cpu_and_2(pcp, val)      percpu_to_op("and", (pcp), val)
 263 #define __this_cpu_and_4(pcp, val)      percpu_to_op("and", (pcp), val)
 264 #define __this_cpu_or_1(pcp, val)       percpu_to_op("or", (pcp), val)
 265 #define __this_cpu_or_2(pcp, val)       percpu_to_op("or", (pcp), val)
 266 #define __this_cpu_or_4(pcp, val)       percpu_to_op("or", (pcp), val)
 267 #define __this_cpu_xor_1(pcp, val)      percpu_to_op("xor", (pcp), val)
 268 #define __this_cpu_xor_2(pcp, val)      percpu_to_op("xor", (pcp), val)
 269 #define __this_cpu_xor_4(pcp, val)      percpu_to_op("xor", (pcp), val)
 270
 271 #define this_cpu_read_1(pcp)            percpu_from_op("mov", (pcp), "m"(pcp))
 272 #define this_cpu_read_2(pcp)            percpu_from_op("mov", (pcp), "m"(pcp))
 273 #define this_cpu_read_4(pcp)            percpu_from_op("mov", (pcp), "m"(pcp))
 274 #define this_cpu_write_1(pcp, val)      percpu_to_op("mov", (pcp), val)
 275 #define this_cpu_write_2(pcp, val)      percpu_to_op("mov", (pcp), val)
 276 #define this_cpu_write_4(pcp, val)      percpu_to_op("mov", (pcp), val)
 277 #define this_cpu_add_1(pcp, val)        percpu_add_op((pcp), val)
 278 #define this_cpu_add_2(pcp, val)        percpu_add_op((pcp), val)
 279 #define this_cpu_add_4(pcp, val)        percpu_add_op((pcp), val)
 280 #define this_cpu_and_1(pcp, val)        percpu_to_op("and", (pcp), val)
 281 #define this_cpu_and_2(pcp, val)        percpu_to_op("and", (pcp), val)
 282 #define this_cpu_and_4(pcp, val)        percpu_to_op("and", (pcp), val)
 283 #define this_cpu_or_1(pcp, val)         percpu_to_op("or", (pcp), val)
 284 #define this_cpu_or_2(pcp, val)         percpu_to_op("or", (pcp), val)
 285 #define this_cpu_or_4(pcp, val)         percpu_to_op("or", (pcp), val)
 286 #define this_cpu_xor_1(pcp, val)        percpu_to_op("xor", (pcp), val)
 287 #define this_cpu_xor_2(pcp, val)        percpu_to_op("xor", (pcp), val)
 288 #define this_cpu_xor_4(pcp, val)        percpu_to_op("xor", (pcp), val)
 289
 290 #define irqsafe_cpu_add_1(pcp, val)     percpu_add_op((pcp), val)
 291 #define irqsafe_cpu_add_2(pcp, val)     percpu_add_op((pcp), val)
 292 #define irqsafe_cpu_add_4(pcp, val)     percpu_add_op((pcp), val)
 293 #define irqsafe_cpu_and_1(pcp, val)     percpu_to_op("and", (pcp), val)
 294 #define irqsafe_cpu_and_2(pcp, val)     percpu_to_op("and", (pcp), val)
 295 #define irqsafe_cpu_and_4(pcp, val)     percpu_to_op("and", (pcp), val)
 296 #define irqsafe_cpu_or_1(pcp, val)      percpu_to_op("or", (pcp), val)
 297 #define irqsafe_cpu_or_2(pcp, val)      percpu_to_op("or", (pcp), val)
 298 #define irqsafe_cpu_or_4(pcp, val)      percpu_to_op("or", (pcp), val)
 299 #define irqsafe_cpu_xor_1(pcp, val)     percpu_to_op("xor", (pcp), val)
 300 #define irqsafe_cpu_xor_2(pcp, val)     percpu_to_op("xor", (pcp), val)
 301 #define irqsafe_cpu_xor_4(pcp, val)     percpu_to_op("xor", (pcp), val)
 302
 303 /*
 304  * Per cpu atomic 64 bit operations are only available under 64 bit.
 305  * 32 bit must fall back to generic operations.
 306  */
 307 #ifdef CONFIG_X86_64
 308 #define __this_cpu_read_8(pcp)          percpu_from_op("mov", (pcp), "m"(pcp))
 309 #define __this_cpu_write_8(pcp, val)    percpu_to_op("mov", (pcp), val)
 310 #define __this_cpu_add_8(pcp, val)      percpu_add_op((pcp), val)
 311 #define __this_cpu_and_8(pcp, val)      percpu_to_op("and", (pcp), val)
 312 #define __this_cpu_or_8(pcp, val)       percpu_to_op("or", (pcp), val)
 313 #define __this_cpu_xor_8(pcp, val)      percpu_to_op("xor", (pcp), val)
 314
 315 #define this_cpu_read_8(pcp)            percpu_from_op("mov", (pcp), "m"(pcp))
 316 #define this_cpu_write_8(pcp, val)      percpu_to_op("mov", (pcp), val)
 317 #define this_cpu_add_8(pcp, val)        percpu_add_op((pcp), val)
 318 #define this_cpu_and_8(pcp, val)        percpu_to_op("and", (pcp), val)
 319 #define this_cpu_or_8(pcp, val)         percpu_to_op("or", (pcp), val)
 320 #define this_cpu_xor_8(pcp, val)        percpu_to_op("xor", (pcp), val)
 321
 322 #define irqsafe_cpu_add_8(pcp, val)     percpu_add_op((pcp), val)
 323 #define irqsafe_cpu_and_8(pcp, val)     percpu_to_op("and", (pcp), val)
 324 #define irqsafe_cpu_or_8(pcp, val)      percpu_to_op("or", (pcp), val)
 325 #define irqsafe_cpu_xor_8(pcp, val)     percpu_to_op("xor", (pcp), val)
 326
 327 #endif
 328
 329 /* This is not atomic against other CPUs -- CPU preemption needs to be off */
 330 #define x86_test_and_clear_bit_percpu(bit, var)                         \
 331 ({                                                                      \
 332         int old__;                                                      \
 333         asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0"           \
 334                      : "=r" (old__), "+m" (var)                         \
 335                      : "dIr" (bit));                                    \
 336         old__;                                                          \
 337 })
 338
 339 #include <asm-generic/percpu.h>
 340
 341 /* We can use this directly for local CPU (faster). */
 342 DECLARE_PER_CPU(unsigned long, this_cpu_off);
 343
 344 #endif /* !__ASSEMBLY__ */
 345
 346 #ifdef CONFIG_SMP
 347
 348 /*
 349  * Define the "EARLY_PER_CPU" macros.  These are used for some per_cpu
 350  * variables that are initialized and accessed before there are per_cpu
 351  * areas allocated.
 352  */
 353
 354 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)                  \
 355         DEFINE_PER_CPU(_type, _name) = _initvalue;                      \
 356         __typeof__(_type) _name##_early_map[NR_CPUS] __initdata =       \
 357                                 { [0 ... NR_CPUS-1] = _initvalue };     \
 358         __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
 359
 360 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 361         EXPORT_PER_CPU_SYMBOL(_name)
 362
 363 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 364         DECLARE_PER_CPU(_type, _name);                          \
 365         extern __typeof__(_type) *_name##_early_ptr;            \
 366         extern __typeof__(_type)  _name##_early_map[]
 367
 368 #define early_per_cpu_ptr(_name) (_name##_early_ptr)
 369 #define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
 370 #define early_per_cpu(_name, _cpu)                              \
 371         *(early_per_cpu_ptr(_name) ?                            \
 372                 &early_per_cpu_ptr(_name)[_cpu] :               \
 373                 &per_cpu(_name, _cpu))
 374
 375 #else   /* !CONFIG_SMP */
 376 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)          \
 377         DEFINE_PER_CPU(_type, _name) = _initvalue
 378
 379 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 380         EXPORT_PER_CPU_SYMBOL(_name)
 381
 382 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 383         DECLARE_PER_CPU(_type, _name)
 384
 385 #define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
 386 #define early_per_cpu_ptr(_name) NULL
 387 /* no early_per_cpu_map() */
 388
 389 #endif  /* !CONFIG_SMP */
 390
 391 #endif /* _ASM_X86_PERCPU_H */