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 #else /* ...!ASSEMBLY */
  38
  39 #include <linux/stringify.h>
  40
  41 #ifdef CONFIG_SMP
  42 #define __percpu_arg(x)         "%%"__stringify(__percpu_seg)":%P" #x
  43 #define __my_cpu_offset         percpu_read(this_cpu_off)
  44 #else
  45 #define __percpu_arg(x)         "%" #x
  46 #endif
  47
  48 /* For arch-specific code, we can use direct single-insn ops (they
  49  * don't give an lvalue though). */
  50 extern void __bad_percpu_size(void);
  51
  52 #define percpu_to_op(op, var, val)                      \
  53 do {                                                    \
  54         typedef typeof(var) T__;                        \
  55         if (0) {                                        \
  56                 T__ tmp__;                              \
  57                 tmp__ = (val);                          \
  58         }                                               \
  59         switch (sizeof(var)) {                          \
  60         case 1:                                         \
  61                 asm(op "b %1,"__percpu_arg(0)           \
  62                     : "+m" (var)                        \
  63                     : "ri" ((T__)val));                 \
  64                 break;                                  \
  65         case 2:                                         \
  66                 asm(op "w %1,"__percpu_arg(0)           \
  67                     : "+m" (var)                        \
  68                     : "ri" ((T__)val));                 \
  69                 break;                                  \
  70         case 4:                                         \
  71                 asm(op "l %1,"__percpu_arg(0)           \
  72                     : "+m" (var)                        \
  73                     : "ri" ((T__)val));                 \
  74                 break;                                  \
  75         case 8:                                         \
  76                 asm(op "q %1,"__percpu_arg(0)           \
  77                     : "+m" (var)                        \
  78                     : "r" ((T__)val));                  \
  79                 break;                                  \
  80         default: __bad_percpu_size();                   \
  81         }                                               \
  82 } while (0)
  83
  84 #define percpu_from_op(op, var)                         \
  85 ({                                                      \
  86         typeof(var) ret__;                              \
  87         switch (sizeof(var)) {                          \
  88         case 1:                                         \
  89                 asm(op "b "__percpu_arg(1)",%0"         \
  90                     : "=r" (ret__)                      \
  91                     : "m" (var));                       \
  92                 break;                                  \
  93         case 2:                                         \
  94                 asm(op "w "__percpu_arg(1)",%0"         \
  95                     : "=r" (ret__)                      \
  96                     : "m" (var));                       \
  97                 break;                                  \
  98         case 4:                                         \
  99                 asm(op "l "__percpu_arg(1)",%0"         \
 100                     : "=r" (ret__)                      \
 101                     : "m" (var));                       \
 102                 break;                                  \
 103         case 8:                                         \
 104                 asm(op "q "__percpu_arg(1)",%0"         \
 105                     : "=r" (ret__)                      \
 106                     : "m" (var));                       \
 107                 break;                                  \
 108         default: __bad_percpu_size();                   \
 109         }                                               \
 110         ret__;                                          \
 111 })
 112
 113 #define percpu_read(var)        percpu_from_op("mov", per_cpu__##var)
 114 #define percpu_write(var, val)  percpu_to_op("mov", per_cpu__##var, val)
 115 #define percpu_add(var, val)    percpu_to_op("add", per_cpu__##var, val)
 116 #define percpu_sub(var, val)    percpu_to_op("sub", per_cpu__##var, val)
 117 #define percpu_and(var, val)    percpu_to_op("and", per_cpu__##var, val)
 118 #define percpu_or(var, val)     percpu_to_op("or", per_cpu__##var, val)
 119 #define percpu_xor(var, val)    percpu_to_op("xor", per_cpu__##var, val)
 120
 121 /* This is not atomic against other CPUs -- CPU preemption needs to be off */
 122 #define x86_test_and_clear_bit_percpu(bit, var)                         \
 123 ({                                                                      \
 124         int old__;                                                      \
 125         asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0"           \
 126                      : "=r" (old__), "+m" (per_cpu__##var)              \
 127                      : "dIr" (bit));                                    \
 128         old__;                                                          \
 129 })
 130
 131 #include <asm-generic/percpu.h>
 132
 133 /* We can use this directly for local CPU (faster). */
 134 DECLARE_PER_CPU(unsigned long, this_cpu_off);
 135
 136 #endif /* !__ASSEMBLY__ */
 137
 138 #ifdef CONFIG_SMP
 139
 140 /*
 141  * Define the "EARLY_PER_CPU" macros.  These are used for some per_cpu
 142  * variables that are initialized and accessed before there are per_cpu
 143  * areas allocated.
 144  */
 145
 146 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)                  \
 147         DEFINE_PER_CPU(_type, _name) = _initvalue;                      \
 148         __typeof__(_type) _name##_early_map[NR_CPUS] __initdata =       \
 149                                 { [0 ... NR_CPUS-1] = _initvalue };     \
 150         __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
 151
 152 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 153         EXPORT_PER_CPU_SYMBOL(_name)
 154
 155 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 156         DECLARE_PER_CPU(_type, _name);                          \
 157         extern __typeof__(_type) *_name##_early_ptr;            \
 158         extern __typeof__(_type)  _name##_early_map[]
 159
 160 #define early_per_cpu_ptr(_name) (_name##_early_ptr)
 161 #define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
 162 #define early_per_cpu(_name, _cpu)                              \
 163         *(early_per_cpu_ptr(_name) ?                            \
 164                 &early_per_cpu_ptr(_name)[_cpu] :               \
 165                 &per_cpu(_name, _cpu))
 166
 167 #else   /* !CONFIG_SMP */
 168 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)          \
 169         DEFINE_PER_CPU(_type, _name) = _initvalue
 170
 171 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name)                      \
 172         EXPORT_PER_CPU_SYMBOL(_name)
 173
 174 #define DECLARE_EARLY_PER_CPU(_type, _name)                     \
 175         DECLARE_PER_CPU(_type, _name)
 176
 177 #define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
 178 #define early_per_cpu_ptr(_name) NULL
 179 /* no early_per_cpu_map() */
 180
 181 #endif  /* !CONFIG_SMP */
 182
 183 #endif /* _ASM_X86_PERCPU_H */