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