cmpxchg.h

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#ifndef __ASM_SH_CMPXCHG_H
#define __ASM_SH_CMPXCHG_H

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 */

#include <linux/compiler.h>
#include <linux/types.h>

#if defined(CONFIG_GUSA_RB)
#include <asm/cmpxchg-grb.h>
#elif defined(CONFIG_CPU_SH4A)
#include <asm/cmpxchg-llsc.h>
#else
#include <asm/cmpxchg-irq.h>
#endif

extern void __xchg_called_with_bad_pointer(void);

#define __xchg(ptr, x, size)                \
({                          \
    unsigned long __xchg__res;          \
    volatile void *__xchg_ptr = (ptr);      \
    switch (size) {                 \
    case 4:                     \
        __xchg__res = xchg_u32(__xchg_ptr, x);  \
        break;                  \
    case 1:                     \
        __xchg__res = xchg_u8(__xchg_ptr, x);   \
        break;                  \
    default:                    \
        __xchg_called_with_bad_pointer();   \
        __xchg__res = x;            \
        break;                  \
    }                       \
                            \
    __xchg__res;                    \
})

#define xchg(ptr,x) \
    ((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))

/* This function doesn't exist, so you'll get a linker error
 * if something tries to do an invalid cmpxchg(). */
extern void __cmpxchg_called_with_bad_pointer(void);

#define __HAVE_ARCH_CMPXCHG 1

static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
        unsigned long new, int size)
{
    switch (size) {
    case 4:
        return __cmpxchg_u32(ptr, old, new);
    }
    __cmpxchg_called_with_bad_pointer();
    return old;
}

#define cmpxchg(ptr,o,n)                         \
  ({                                     \
     __typeof__(*(ptr)) _o_ = (o);                   \
     __typeof__(*(ptr)) _n_ = (n);                   \
     (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,       \
                    (unsigned long)_n_, sizeof(*(ptr))); \
  })

#endif /* __ASM_SH_CMPXCHG_H */