arch/sh/include/asm/cmpxchg.h

   1 #ifndef __ASM_SH_CMPXCHG_H
   2 #define __ASM_SH_CMPXCHG_H
   3
   4 /*
   5  * Atomic operations that C can't guarantee us.  Useful for
   6  * resource counting etc..
   7  */
   8
   9 #include <linux/compiler.h>
  10 #include <linux/types.h>
  11
  12 #if defined(CONFIG_GUSA_RB)
  13 #include <asm/cmpxchg-grb.h>
  14 #elif defined(CONFIG_CPU_SH4A)
  15 #include <asm/cmpxchg-llsc.h>
  16 #else
  17 #include <asm/cmpxchg-irq.h>
  18 #endif
  19
  20 extern void __xchg_called_with_bad_pointer(void);
  21
  22 #define __xchg(ptr, x, size)                            \
  23 ({                                                      \
  24         unsigned long __xchg__res;                      \
  25         volatile void *__xchg_ptr = (ptr);              \
  26         switch (size) {                                 \
  27         case 4:                                         \
  28                 __xchg__res = xchg_u32(__xchg_ptr, x);  \
  29                 break;                                  \
  30         case 2:                                         \
  31                 __xchg__res = xchg_u16(__xchg_ptr, x);  \
  32                 break;                                  \
  33         case 1:                                         \
  34                 __xchg__res = xchg_u8(__xchg_ptr, x);   \
  35                 break;                                  \
  36         default:                                        \
  37                 __xchg_called_with_bad_pointer();       \
  38                 __xchg__res = x;                        \
  39                 break;                                  \
  40         }                                               \
  41                                                         \
  42         __xchg__res;                                    \
  43 })
  44
  45 #define xchg(ptr,x)     \
  46         ((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
  47
  48 /* This function doesn't exist, so you'll get a linker error
  49  * if something tries to do an invalid cmpxchg(). */
  50 extern void __cmpxchg_called_with_bad_pointer(void);
  51
  52 static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
  53                 unsigned long new, int size)
  54 {
  55         switch (size) {
  56         case 4:
  57                 return __cmpxchg_u32(ptr, old, new);
  58         }
  59         __cmpxchg_called_with_bad_pointer();
  60         return old;
  61 }
  62
  63 #define cmpxchg(ptr,o,n)                                                 \
  64   ({                                                                     \
  65      __typeof__(*(ptr)) _o_ = (o);                                       \
  66      __typeof__(*(ptr)) _n_ = (n);                                       \
  67      (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,           \
  68                                     (unsigned long)_n_, sizeof(*(ptr))); \
  69   })
  70
  71 #endif /* __ASM_SH_CMPXCHG_H */