kernel/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 1:                                         \
  31                 __xchg__res = xchg_u8(__xchg_ptr, x);   \
  32                 break;                                  \
  33         default:                                        \
  34                 __xchg_called_with_bad_pointer();       \
  35                 __xchg__res = x;                        \
  36                 break;                                  \
  37         }                                               \
  38                                                         \
  39         __xchg__res;                                    \
  40 })
  41
  42 #define xchg(ptr,x)     \
  43         ((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
  44
  45 /* This function doesn't exist, so you'll get a linker error
  46  * if something tries to do an invalid cmpxchg(). */
  47 extern void __cmpxchg_called_with_bad_pointer(void);
  48
  49 #define __HAVE_ARCH_CMPXCHG 1
  50
  51 static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
  52                 unsigned long new, int size)
  53 {
  54         switch (size) {
  55         case 4:
  56                 return __cmpxchg_u32(ptr, old, new);
  57         }
  58         __cmpxchg_called_with_bad_pointer();
  59         return old;
  60 }
  61
  62 #define cmpxchg(ptr,o,n)                                                 \
  63   ({                                                                     \
  64      __typeof__(*(ptr)) _o_ = (o);                                       \
  65      __typeof__(*(ptr)) _n_ = (n);                                       \
  66      (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,           \
  67                                     (unsigned long)_n_, sizeof(*(ptr))); \
  68   })
  69
  70 #endif /* __ASM_SH_CMPXCHG_H */