cmpxchg_64.h

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/* 64-bit atomic xchg() and cmpxchg() definitions.
 *
 * Copyright (C) 1996, 1997, 2000 David S. Miller ([email protected])
 */

#ifndef __ARCH_SPARC64_CMPXCHG__
#define __ARCH_SPARC64_CMPXCHG__

static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int val)
{
    unsigned long tmp1, tmp2;

    __asm__ __volatile__(
"   mov     %0, %1\n"
"1: lduw        [%4], %2\n"
"   cas     [%4], %2, %0\n"
"   cmp     %2, %0\n"
"   bne,a,pn    %%icc, 1b\n"
"    mov        %1, %0\n"
    : "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
    : "0" (val), "r" (m)
    : "cc", "memory");
    return val;
}

static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long val)
{
    unsigned long tmp1, tmp2;

    __asm__ __volatile__(
"   mov     %0, %1\n"
"1: ldx     [%4], %2\n"
"   casx        [%4], %2, %0\n"
"   cmp     %2, %0\n"
"   bne,a,pn    %%xcc, 1b\n"
"    mov        %1, %0\n"
    : "=&r" (val), "=&r" (tmp1), "=&r" (tmp2)
    : "0" (val), "r" (m)
    : "cc", "memory");
    return val;
}

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

extern void __xchg_called_with_bad_pointer(void);

static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
                       int size)
{
    switch (size) {
    case 4:
        return xchg32(ptr, x);
    case 8:
        return xchg64(ptr, x);
    }
    __xchg_called_with_bad_pointer();
    return x;
}

/*
 * Atomic compare and exchange.  Compare OLD with MEM, if identical,
 * store NEW in MEM.  Return the initial value in MEM.  Success is
 * indicated by comparing RETURN with OLD.
 */

#include <asm-generic/cmpxchg-local.h>

#define __HAVE_ARCH_CMPXCHG 1

static inline unsigned long
__cmpxchg_u32(volatile int *m, int old, int new)
{
    __asm__ __volatile__("cas [%2], %3, %0"
                 : "=&r" (new)
                 : "0" (new), "r" (m), "r" (old)
                 : "memory");

    return new;
}

static inline unsigned long
__cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
{
    __asm__ __volatile__("casx [%2], %3, %0"
                 : "=&r" (new)
                 : "0" (new), "r" (m), "r" (old)
                 : "memory");

    return new;
}

/* 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);

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);
        case 8:
            return __cmpxchg_u64(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))); \
  })

/*
 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 * them available.
 */

static inline unsigned long __cmpxchg_local(volatile void *ptr,
                      unsigned long old,
                      unsigned long new, int size)
{
    switch (size) {
    case 4:
    case 8: return __cmpxchg(ptr, old, new, size);
    default:
        return __cmpxchg_local_generic(ptr, old, new, size);
    }

    return old;
}

#define cmpxchg_local(ptr, o, n)                    \
    ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
            (unsigned long)(n), sizeof(*(ptr))))
#define cmpxchg64_local(ptr, o, n)                  \
  ({                                    \
    BUILD_BUG_ON(sizeof(*(ptr)) != 8);              \
    cmpxchg_local((ptr), (o), (n));                 \
  })

#endif /* __ARCH_SPARC64_CMPXCHG__ */