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 #include <asm/sections.h>
  47
  48 #define __addr_to_pcpu_ptr(addr)                                        \
  49         (void *)((unsigned long)(addr) - (unsigned long)pcpu_base_addr  \
  50                  + (unsigned long)__per_cpu_start)
  51 #define __pcpu_ptr_to_addr(ptr)                                         \
  52         (void *)((unsigned long)(ptr) + (unsigned long)pcpu_base_addr   \
  53                  - (unsigned long)__per_cpu_start)
  54
  55 #ifdef CONFIG_SMP
  56 #define __percpu_arg(x)         "%%"__stringify(__percpu_seg)":%P" #x
  57 #define __my_cpu_offset         percpu_read(this_cpu_off)
  58 #else
  59 #define __percpu_arg(x)         "%" #x
  60 #endif
  61
  62 /*
  63  * Initialized pointers to per-cpu variables needed for the boot
  64  * processor need to use these macros to get the proper address
  65  * offset from __per_cpu_load on SMP.
  66  *
  67  * There also must be an entry in vmlinux_64.lds.S
  68  */
  69 #define DECLARE_INIT_PER_CPU(var) \
  70        extern typeof(per_cpu_var(var)) init_per_cpu_var(var)
  71
  72 #ifdef CONFIG_X86_64_SMP
  73 #define init_per_cpu_var(var)  init_per_cpu__##var
  74 #else
  75 #define init_per_cpu_var(var)  per_cpu_var(var)
  76 #endif
  77
  78 /* For arch-specific code, we can use direct single-insn ops (they
  79  * don't give an lvalue though). */
  80 extern void __bad_percpu_size(void);
  81
  82 #define percpu_to_op(op, var, val)                      \
  83 do {                                                    \
  84         typedef typeof(var) T__;                        \
  85         if (0) {                                        \
  86                 T__ tmp__;                              \
  87                 tmp__ = (val);                          \
  88         }                                               \
  89         switch (sizeof(var)) {                          \
  90         case 1:                                         \
  91                 asm(op "b %1,"__percpu_arg(0)           \
  92                     : "+m" (var)                        \
  93                     : "ri" ((T__)val));                 \
  94                 break;                                  \
  95         case 2:                                         \
  96                 asm(op "w %1,"__percpu_arg(0)           \
  97                     : "+m" (var)                        \
  98                     : "ri" ((T__)val));                 \
  99                 break;                                  \
 100         case 4:                                         \
 101                 asm(op "l %1,"__percpu_arg(0)           \
 102                     : "+m" (var)                        \
 103                     : "ri" ((T__)val));                 \
 104                 break;                                  \
 105         case 8:                                         \
 106                 asm(op "q %1,"__percpu_arg(0)           \
 107                     : "+m" (var)                        \
 108                     : "re" ((T__)val));                 \
 109                 break;                                  \
 110         default: __bad_percpu_size();                   \
 111         }                                               \
 112 } while (0)
 113
 114 #define percpu_from_op(op, var)                         \
 115 ({                                                      \
 116         typeof(var) ret__;                              \
 117         switch (sizeof(var)) {                          \
 118         case 1:                                         \
 119                 asm(op "b "__percpu_arg(1)",%0"         \
 120                     : "=r" (ret__)                      \
 121                     : "m" (var));                       \
 122                 break;                                  \
 123         case 2:                                         \
 124                 asm(op "w "__percpu_arg(1)",%0"         \
 125                     : "=r" (ret__)                      \
 126                     : "m" (var));                       \
 127                 break;                                  \
 128         case 4:                                         \
 129                 asm(op "l "__percpu_arg(1)",%0"         \
 130                     : "=r" (ret__)                      \
 131                     : "m" (var));                       \
 132                 break;                                  \
 133         case 8:                                         \
 134                 asm(op "q "__percpu_arg(1)",%0"         \
 135                     : "=r" (ret__)                      \
 136                     : "m" (var));                       \
 137                 break;                                  \
 138         default: __bad_percpu_size();                   \
 139         }                                               \
 140         ret__;                                          \
 141 })
 142
 143 #define percpu_read(var)        percpu_from_op("mov", per_cpu__##var)
 144 #define percpu_write(var, val)  percpu_to_op("mov", per_cpu__##var, val)
 145 #define percpu_add(var, val)    percpu_to_op("add", per_cpu__##var, val)
 146 #define percpu_sub(var, val)    percpu_to_op("sub", per_cpu__##var, val)
 147 #define percpu_and(var, val)    percpu_to_op("and", per_cpu__##var, val)
 148 #define percpu_or(var, val)     percpu_to_op("or", per_cpu__##var, val)
 149 #define percpu_xor(var, val)    percpu_to_op("xor", per_cpu__##var, val)
 150
 151 /* This is not atomic against other CPUs -- CPU preemption needs to be off */
 152 #define x86_test_and_clear_bit_percpu(bit, var)                         \
 153 ({                                                                      \
 154         int old__;                                                      \
 155         asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0"           \
 156                      : "=r" (old__), "+m" (per_cpu__##var)              \
 157                      : "dIr" (bit));                                    \
 158         old__;                                                          \
 159 })
 160
 161 #include <asm-generic/percpu.h>
 162
 163 /* We can use this directly for local CPU (faster). */
 164 DECLARE_PER_CPU(unsigned long, this_cpu_off);
 165
 166 #endif /* !__ASSEMBLY__ */
 167
 168 #ifdef CONFIG_SMP
 169
 170 /*
 171  * Define the "EARLY_PER_CPU" macros.  These are used for some per_cpu
 172  * variables that are initialized and accessed before there are per_cpu
 173  * areas allocated.
 174  */
 175
 176 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)                  \
 177         DEFINE_PER_CPU(_type, _name) = _initvalue;                      \
 178         __typeof__(_type) _name##_early_map[NR_CPUS] __initdata =       \
 179                                 { [0 ... NR_CPUS-1] = _initvalue };     \
 180         __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
 181
 182 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 183         EXPORT_PER_CPU_SYMBOL(_name)
 184
 185 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 186         DECLARE_PER_CPU(_type, _name);                          \
 187         extern __typeof__(_type) *_name##_early_ptr;            \
 188         extern __typeof__(_type)  _name##_early_map[]
 189
 190 #define early_per_cpu_ptr(_name) (_name##_early_ptr)
 191 #define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
 192 #define early_per_cpu(_name, _cpu)                              \
 193         *(early_per_cpu_ptr(_name) ?                            \
 194                 &early_per_cpu_ptr(_name)[_cpu] :               \
 195                 &per_cpu(_name, _cpu))
 196
 197 #else   /* !CONFIG_SMP */
 198 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)          \
 199         DEFINE_PER_CPU(_type, _name) = _initvalue
 200
 201 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 202         EXPORT_PER_CPU_SYMBOL(_name)
 203
 204 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 205         DECLARE_PER_CPU(_type, _name)
 206
 207 #define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
 208 #define early_per_cpu_ptr(_name) NULL
 209 /* no early_per_cpu_map() */
 210
 211 #endif  /* !CONFIG_SMP */
 212
 213 #endif /* _ASM_X86_PERCPU_H */