root/arch/sh/include/asm/cmpxchg.h

INCLUDED FROM

DEFINITIONS

1. __cmpxchg

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_SH_CMPXCHG_H
   3 #define __ASM_SH_CMPXCHG_H
   4 
   5 /*
   6  * Atomic operations that C can't guarantee us.  Useful for
   7  * resource counting etc..
   8  */
   9 
  10 #include <linux/compiler.h>
  11 #include <linux/types.h>
  12 
  13 #if defined(CONFIG_GUSA_RB)
  14 #include <asm/cmpxchg-grb.h>
  15 #elif defined(CONFIG_CPU_SH4A)
  16 #include <asm/cmpxchg-llsc.h>
  17 #elif defined(CONFIG_CPU_J2) && defined(CONFIG_SMP)
  18 #include <asm/cmpxchg-cas.h>
  19 #else
  20 #include <asm/cmpxchg-irq.h>
  21 #endif
  22 
  23 extern void __xchg_called_with_bad_pointer(void);
  24 
  25 #define __xchg(ptr, x, size)                            \
  26 ({                                                      \
  27         unsigned long __xchg__res;                      \
  28         volatile void *__xchg_ptr = (ptr);              \
  29         switch (size) {                                 \
  30         case 4:                                         \
  31                 __xchg__res = xchg_u32(__xchg_ptr, x);  \
  32                 break;                                  \
  33         case 2:                                         \
  34                 __xchg__res = xchg_u16(__xchg_ptr, x);  \
  35                 break;                                  \
  36         case 1:                                         \
  37                 __xchg__res = xchg_u8(__xchg_ptr, x);   \
  38                 break;                                  \
  39         default:                                        \
  40                 __xchg_called_with_bad_pointer();       \
  41                 __xchg__res = x;                        \
  42                 break;                                  \
  43         }                                               \
  44                                                         \
  45         __xchg__res;                                    \
  46 })
  47 
  48 #define xchg(ptr,x)     \
  49         ((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
  50 
  51 /* This function doesn't exist, so you'll get a linker error
  52  * if something tries to do an invalid cmpxchg(). */
  53 extern void __cmpxchg_called_with_bad_pointer(void);
  54 
  55 static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
  56                 unsigned long new, int size)
  57 {
  58         switch (size) {
  59         case 4:
  60                 return __cmpxchg_u32(ptr, old, new);
  61         }
  62         __cmpxchg_called_with_bad_pointer();
  63         return old;
  64 }
  65 
  66 #define cmpxchg(ptr,o,n)                                                 \
  67   ({                                                                     \
  68      __typeof__(*(ptr)) _o_ = (o);                                       \
  69      __typeof__(*(ptr)) _n_ = (n);                                       \
  70      (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,           \
  71                                     (unsigned long)_n_, sizeof(*(ptr))); \
  72   })
  73 
  74 #endif /* __ASM_SH_CMPXCHG_H */