include/asm-x86/percpu.h

   1 #ifndef _ASM_X86_PERCPU_H_
   2 #define _ASM_X86_PERCPU_H_
   3
   4 #ifdef CONFIG_X86_64
   5 #include <linux/compiler.h>
   6
   7 /* Same as asm-generic/percpu.h, except that we store the per cpu offset
   8    in the PDA. Longer term the PDA and every per cpu variable
   9    should be just put into a single section and referenced directly
  10    from %gs */
  11
  12 #ifdef CONFIG_SMP
  13 #include <asm/pda.h>
  14
  15 #define __per_cpu_offset(cpu) (cpu_pda(cpu)->data_offset)
  16 #define __my_cpu_offset read_pda(data_offset)
  17
  18 #define per_cpu_offset(x) (__per_cpu_offset(x))
  19
  20 #endif
  21 #include <asm-generic/percpu.h>
  22
  23 DECLARE_PER_CPU(struct x8664_pda, pda);
  24
  25 #else /* CONFIG_X86_64 */
  26
  27 #ifdef __ASSEMBLY__
  28
  29 /*
  30  * PER_CPU finds an address of a per-cpu variable.
  31  *
  32  * Args:
  33  *    var - variable name
  34  *    reg - 32bit register
  35  *
  36  * The resulting address is stored in the "reg" argument.
  37  *
  38  * Example:
  39  *    PER_CPU(cpu_gdt_descr, %ebx)
  40  */
  41 #ifdef CONFIG_SMP
  42 #define PER_CPU(var, reg)                               \
  43         movl %fs:per_cpu__##this_cpu_off, reg;          \
  44         lea per_cpu__##var(reg), reg
  45 #define PER_CPU_VAR(var)        %fs:per_cpu__##var
  46 #else /* ! SMP */
  47 #define PER_CPU(var, reg)                       \
  48         movl $per_cpu__##var, reg
  49 #define PER_CPU_VAR(var)        per_cpu__##var
  50 #endif  /* SMP */
  51
  52 #else /* ...!ASSEMBLY */
  53
  54 /*
  55  * PER_CPU finds an address of a per-cpu variable.
  56  *
  57  * Args:
  58  *    var - variable name
  59  *    cpu - 32bit register containing the current CPU number
  60  *
  61  * The resulting address is stored in the "cpu" argument.
  62  *
  63  * Example:
  64  *    PER_CPU(cpu_gdt_descr, %ebx)
  65  */
  66 #ifdef CONFIG_SMP
  67
  68 #define __my_cpu_offset x86_read_percpu(this_cpu_off)
  69
  70 /* fs segment starts at (positive) offset == __per_cpu_offset[cpu] */
  71 #define __percpu_seg "%%fs:"
  72
  73 #else  /* !SMP */
  74
  75 #define __percpu_seg ""
  76
  77 #endif  /* SMP */
  78
  79 #include <asm-generic/percpu.h>
  80
  81 /* We can use this directly for local CPU (faster). */
  82 DECLARE_PER_CPU(unsigned long, this_cpu_off);
  83
  84 /* For arch-specific code, we can use direct single-insn ops (they
  85  * don't give an lvalue though). */
  86 extern void __bad_percpu_size(void);
  87
  88 #define percpu_to_op(op,var,val)                                \
  89         do {                                                    \
  90                 typedef typeof(var) T__;                        \
  91                 if (0) { T__ tmp__; tmp__ = (val); }            \
  92                 switch (sizeof(var)) {                          \
  93                 case 1:                                         \
  94                         asm(op "b %1,"__percpu_seg"%0"          \
  95                             : "+m" (var)                        \
  96                             :"ri" ((T__)val));                  \
  97                         break;                                  \
  98                 case 2:                                         \
  99                         asm(op "w %1,"__percpu_seg"%0"          \
 100                             : "+m" (var)                        \
 101                             :"ri" ((T__)val));                  \
 102                         break;                                  \
 103                 case 4:                                         \
 104                         asm(op "l %1,"__percpu_seg"%0"          \
 105                             : "+m" (var)                        \
 106                             :"ri" ((T__)val));                  \
 107                         break;                                  \
 108                 default: __bad_percpu_size();                   \
 109                 }                                               \
 110         } while (0)
 111
 112 #define percpu_from_op(op,var)                                  \
 113         ({                                                      \
 114                 typeof(var) ret__;                              \
 115                 switch (sizeof(var)) {                          \
 116                 case 1:                                         \
 117                         asm(op "b "__percpu_seg"%1,%0"          \
 118                             : "=r" (ret__)                      \
 119                             : "m" (var));                       \
 120                         break;                                  \
 121                 case 2:                                         \
 122                         asm(op "w "__percpu_seg"%1,%0"          \
 123                             : "=r" (ret__)                      \
 124                             : "m" (var));                       \
 125                         break;                                  \
 126                 case 4:                                         \
 127                         asm(op "l "__percpu_seg"%1,%0"          \
 128                             : "=r" (ret__)                      \
 129                             : "m" (var));                       \
 130                         break;                                  \
 131                 default: __bad_percpu_size();                   \
 132                 }                                               \
 133                 ret__; })
 134
 135 #define x86_read_percpu(var) percpu_from_op("mov", per_cpu__##var)
 136 #define x86_write_percpu(var,val) percpu_to_op("mov", per_cpu__##var, val)
 137 #define x86_add_percpu(var,val) percpu_to_op("add", per_cpu__##var, val)
 138 #define x86_sub_percpu(var,val) percpu_to_op("sub", per_cpu__##var, val)
 139 #define x86_or_percpu(var,val) percpu_to_op("or", per_cpu__##var, val)
 140 #endif /* !__ASSEMBLY__ */
 141 #endif /* !CONFIG_X86_64 */
 142 #endif /* _ASM_X86_PERCPU_H_ */