include/asm-i386/percpu.h

   1 #ifndef __ARCH_I386_PERCPU__
   2 #define __ARCH_I386_PERCPU__
   3
   4 #ifdef __ASSEMBLY__
   5
   6 /*
   7  * PER_CPU finds an address of a per-cpu variable.
   8  *
   9  * Args:
  10  *    var - variable name
  11  *    reg - 32bit register
  12  *
  13  * The resulting address is stored in the "reg" argument.
  14  *
  15  * Example:
  16  *    PER_CPU(cpu_gdt_descr, %ebx)
  17  */
  18 #ifdef CONFIG_SMP
  19 #define PER_CPU(var, reg)                               \
  20         movl %fs:per_cpu__##this_cpu_off, reg;          \
  21         lea per_cpu__##var(reg), reg
  22 #define PER_CPU_VAR(var)        %fs:per_cpu__##var
  23 #else /* ! SMP */
  24 #define PER_CPU(var, reg)                       \
  25         movl $per_cpu__##var, reg
  26 #define PER_CPU_VAR(var)        per_cpu__##var
  27 #endif  /* SMP */
  28
  29 #else /* ...!ASSEMBLY */
  30
  31 /*
  32  * PER_CPU finds an address of a per-cpu variable.
  33  *
  34  * Args:
  35  *    var - variable name
  36  *    cpu - 32bit register containing the current CPU number
  37  *
  38  * The resulting address is stored in the "cpu" argument.
  39  *
  40  * Example:
  41  *    PER_CPU(cpu_gdt_descr, %ebx)
  42  */
  43 #ifdef CONFIG_SMP
  44 /* Same as generic implementation except for optimized local access. */
  45 #define __GENERIC_PER_CPU
  46
  47 /* This is used for other cpus to find our section. */
  48 extern unsigned long __per_cpu_offset[];
  49
  50 #define per_cpu_offset(x) (__per_cpu_offset[x])
  51
  52 /* Separate out the type, so (int[3], foo) works. */
  53 #define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu__##name
  54 #define DEFINE_PER_CPU(type, name) \
  55     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
  56
  57 /* We can use this directly for local CPU (faster). */
  58 DECLARE_PER_CPU(unsigned long, this_cpu_off);
  59
  60 /* var is in discarded region: offset to particular copy we want */
  61 #define per_cpu(var, cpu) (*({                          \
  62         extern int simple_indentifier_##var(void);      \
  63         RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]); }))
  64
  65 #define __raw_get_cpu_var(var) (*({                                     \
  66         extern int simple_indentifier_##var(void);                      \
  67         RELOC_HIDE(&per_cpu__##var, x86_read_percpu(this_cpu_off));     \
  68 }))
  69
  70 #define __get_cpu_var(var) __raw_get_cpu_var(var)
  71
  72 /* A macro to avoid #include hell... */
  73 #define percpu_modcopy(pcpudst, src, size)                      \
  74 do {                                                            \
  75         unsigned int __i;                                       \
  76         for_each_possible_cpu(__i)                              \
  77                 memcpy((pcpudst)+__per_cpu_offset[__i],         \
  78                        (src), (size));                          \
  79 } while (0)
  80
  81 #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
  82 #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
  83
  84 /* fs segment starts at (positive) offset == __per_cpu_offset[cpu] */
  85 #define __percpu_seg "%%fs:"
  86 #else  /* !SMP */
  87 #include <asm-generic/percpu.h>
  88 #define __percpu_seg ""
  89 #endif  /* SMP */
  90
  91 /* For arch-specific code, we can use direct single-insn ops (they
  92  * don't give an lvalue though). */
  93 extern void __bad_percpu_size(void);
  94
  95 #define percpu_to_op(op,var,val)                                \
  96         do {                                                    \
  97                 typedef typeof(var) T__;                        \
  98                 if (0) { T__ tmp__; tmp__ = (val); }            \
  99                 switch (sizeof(var)) {                          \
 100                 case 1:                                         \
 101                         asm(op "b %1,"__percpu_seg"%0"          \
 102                             : "+m" (var)                        \
 103                             :"ri" ((T__)val));                  \
 104                         break;                                  \
 105                 case 2:                                         \
 106                         asm(op "w %1,"__percpu_seg"%0"          \
 107                             : "+m" (var)                        \
 108                             :"ri" ((T__)val));                  \
 109                         break;                                  \
 110                 case 4:                                         \
 111                         asm(op "l %1,"__percpu_seg"%0"          \
 112                             : "+m" (var)                        \
 113                             :"ri" ((T__)val));                  \
 114                         break;                                  \
 115                 default: __bad_percpu_size();                   \
 116                 }                                               \
 117         } while (0)
 118
 119 #define percpu_from_op(op,var)                                  \
 120         ({                                                      \
 121                 typeof(var) ret__;                              \
 122                 switch (sizeof(var)) {                          \
 123                 case 1:                                         \
 124                         asm(op "b "__percpu_seg"%1,%0"          \
 125                             : "=r" (ret__)                      \
 126                             : "m" (var));                       \
 127                         break;                                  \
 128                 case 2:                                         \
 129                         asm(op "w "__percpu_seg"%1,%0"          \
 130                             : "=r" (ret__)                      \
 131                             : "m" (var));                       \
 132                         break;                                  \
 133                 case 4:                                         \
 134                         asm(op "l "__percpu_seg"%1,%0"          \
 135                             : "=r" (ret__)                      \
 136                             : "m" (var));                       \
 137                         break;                                  \
 138                 default: __bad_percpu_size();                   \
 139                 }                                               \
 140                 ret__; })
 141
 142 #define x86_read_percpu(var) percpu_from_op("mov", per_cpu__##var)
 143 #define x86_write_percpu(var,val) percpu_to_op("mov", per_cpu__##var, val)
 144 #define x86_add_percpu(var,val) percpu_to_op("add", per_cpu__##var, val)
 145 #define x86_sub_percpu(var,val) percpu_to_op("sub", per_cpu__##var, val)
 146 #define x86_or_percpu(var,val) percpu_to_op("or", per_cpu__##var, val)
 147 #endif /* !__ASSEMBLY__ */
 148
 149 #endif /* __ARCH_I386_PERCPU__ */