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