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/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)         "%" #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(per_cpu_var(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)  per_cpu_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) T__;                        \
  77         if (0) {                                        \
  78                 T__ tmp__;                              \
  79                 tmp__ = (val);                          \
  80         }                                               \
  81         switch (sizeof(var)) {                          \
  82         case 1:                                         \
  83                 asm(op "b %1,"__percpu_arg(0)           \
  84                     : "+m" (var)                        \
  85                     : "ri" ((T__)val));                 \
  86                 break;                                  \
  87         case 2:                                         \
  88                 asm(op "w %1,"__percpu_arg(0)           \
  89                     : "+m" (var)                        \
  90                     : "ri" ((T__)val));                 \
  91                 break;                                  \
  92         case 4:                                         \
  93                 asm(op "l %1,"__percpu_arg(0)           \
  94                     : "+m" (var)                        \
  95                     : "ri" ((T__)val));                 \
  96                 break;                                  \
  97         case 8:                                         \
  98                 asm(op "q %1,"__percpu_arg(0)           \
  99                     : "+m" (var)                        \
 100                     : "re" ((T__)val));                 \
 101                 break;                                  \
 102         default: __bad_percpu_size();                   \
 103         }                                               \
 104 } while (0)
 105
 106 #define percpu_from_op(op, var)                         \
 107 ({                                                      \
 108         typeof(var) ret__;                              \
 109         switch (sizeof(var)) {                          \
 110         case 1:                                         \
 111                 asm(op "b "__percpu_arg(1)",%0"         \
 112                     : "=r" (ret__)                      \
 113                     : "m" (var));                       \
 114                 break;                                  \
 115         case 2:                                         \
 116                 asm(op "w "__percpu_arg(1)",%0"         \
 117                     : "=r" (ret__)                      \
 118                     : "m" (var));                       \
 119                 break;                                  \
 120         case 4:                                         \
 121                 asm(op "l "__percpu_arg(1)",%0"         \
 122                     : "=r" (ret__)                      \
 123                     : "m" (var));                       \
 124                 break;                                  \
 125         case 8:                                         \
 126                 asm(op "q "__percpu_arg(1)",%0"         \
 127                     : "=r" (ret__)                      \
 128                     : "m" (var));                       \
 129                 break;                                  \
 130         default: __bad_percpu_size();                   \
 131         }                                               \
 132         ret__;                                          \
 133 })
 134
 135 #define percpu_read(var)        percpu_from_op("mov", per_cpu__##var)
 136 #define percpu_write(var, val)  percpu_to_op("mov", per_cpu__##var, val)
 137 #define percpu_add(var, val)    percpu_to_op("add", per_cpu__##var, val)
 138 #define percpu_sub(var, val)    percpu_to_op("sub", per_cpu__##var, val)
 139 #define percpu_and(var, val)    percpu_to_op("and", per_cpu__##var, val)
 140 #define percpu_or(var, val)     percpu_to_op("or", per_cpu__##var, val)
 141 #define percpu_xor(var, val)    percpu_to_op("xor", per_cpu__##var, val)
 142
 143 /* This is not atomic against other CPUs -- CPU preemption needs to be off */
 144 #define x86_test_and_clear_bit_percpu(bit, var)                         \
 145 ({                                                                      \
 146         int old__;                                                      \
 147         asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0"           \
 148                      : "=r" (old__), "+m" (per_cpu__##var)              \
 149                      : "dIr" (bit));                                    \
 150         old__;                                                          \
 151 })
 152
 153 #include <asm-generic/percpu.h>
 154
 155 /* We can use this directly for local CPU (faster). */
 156 DECLARE_PER_CPU(unsigned long, this_cpu_off);
 157
 158 #endif /* !__ASSEMBLY__ */
 159
 160 #ifdef CONFIG_SMP
 161
 162 /*
 163  * Define the "EARLY_PER_CPU" macros.  These are used for some per_cpu
 164  * variables that are initialized and accessed before there are per_cpu
 165  * areas allocated.
 166  */
 167
 168 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)                  \
 169         DEFINE_PER_CPU(_type, _name) = _initvalue;                      \
 170         __typeof__(_type) _name##_early_map[NR_CPUS] __initdata =       \
 171                                 { [0 ... NR_CPUS-1] = _initvalue };     \
 172         __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
 173
 174 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 175         EXPORT_PER_CPU_SYMBOL(_name)
 176
 177 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 178         DECLARE_PER_CPU(_type, _name);                          \
 179         extern __typeof__(_type) *_name##_early_ptr;            \
 180         extern __typeof__(_type)  _name##_early_map[]
 181
 182 #define early_per_cpu_ptr(_name) (_name##_early_ptr)
 183 #define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
 184 #define early_per_cpu(_name, _cpu)                              \
 185         *(early_per_cpu_ptr(_name) ?                            \
 186                 &early_per_cpu_ptr(_name)[_cpu] :               \
 187                 &per_cpu(_name, _cpu))
 188
 189 #else   /* !CONFIG_SMP */
 190 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)          \
 191         DEFINE_PER_CPU(_type, _name) = _initvalue
 192
 193 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 194         EXPORT_PER_CPU_SYMBOL(_name)
 195
 196 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 197         DECLARE_PER_CPU(_type, _name)
 198
 199 #define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
 200 #define early_per_cpu_ptr(_name) NULL
 201 /* no early_per_cpu_map() */
 202
 203 #endif  /* !CONFIG_SMP */
 204
 205 #endif /* _ASM_X86_PERCPU_H */