/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ALPHA_CMPXCHG_H
#define _ALPHA_CMPXCHG_H

/*
 * Atomic exchange.
 * Since it can be used to implement critical sections
 * it must clobber "memory" (also for interrupts in UP).
 */

static inline unsigned long
____xchg_u8(volatile char *m, unsigned long val)
{
        unsigned long ret, tmp, addr64;

        __asm__ __volatile__(
        "       andnot  %4,7,%3\n"
        "       insbl   %1,%4,%1\n"
        "1:     ldq_l   %2,0(%3)\n"
        "       extbl   %2,%4,%0\n"
        "       mskbl   %2,%4,%2\n"
        "       or      %1,%2,%2\n"
        "       stq_c   %2,0(%3)\n"
        "       beq     %2,2f\n"
        ".subsection 2\n"
        "2:     br      1b\n"
        ".previous"
        : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
        : "r" ((long)m), "1" (val) : "memory");

        return ret;
}

static inline unsigned long
____xchg_u16(volatile short *m, unsigned long val)
{
        unsigned long ret, tmp, addr64;

        __asm__ __volatile__(
        "       andnot  %4,7,%3\n"
        "       inswl   %1,%4,%1\n"
        "1:     ldq_l   %2,0(%3)\n"
        "       extwl   %2,%4,%0\n"
        "       mskwl   %2,%4,%2\n"
        "       or      %1,%2,%2\n"
        "       stq_c   %2,0(%3)\n"
        "       beq     %2,2f\n"
        ".subsection 2\n"
        "2:     br      1b\n"
        ".previous"
        : "=&r" (ret), "=&r" (val), "=&r" (tmp), "=&r" (addr64)
        : "r" ((long)m), "1" (val) : "memory");

        return ret;
}

static inline unsigned long
____xchg_u32(volatile int *m, unsigned long val)
{
        unsigned long dummy;

        __asm__ __volatile__(
        "1:     ldl_l %0,%4\n"
        "       bis $31,%3,%1\n"
        "       stl_c %1,%2\n"
        "       beq %1,2f\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        : "=&r" (val), "=&r" (dummy), "=m" (*m)
        : "rI" (val), "m" (*m) : "memory");

        return val;
}

static inline unsigned long
____xchg_u64(volatile long *m, unsigned long val)
{
        unsigned long dummy;

        __asm__ __volatile__(
        "1:     ldq_l %0,%4\n"
        "       bis $31,%3,%1\n"
        "       stq_c %1,%2\n"
        "       beq %1,2f\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        : "=&r" (val), "=&r" (dummy), "=m" (*m)
        : "rI" (val), "m" (*m) : "memory");

        return val;
}

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

static __always_inline unsigned long
____xchg(volatile void *ptr, unsigned long x, int size)
{
        return
                size == 1 ? ____xchg_u8(ptr, x) :
                size == 2 ? ____xchg_u16(ptr, x) :
                size == 4 ? ____xchg_u32(ptr, x) :
                size == 8 ? ____xchg_u64(ptr, x) :
                        (__xchg_called_with_bad_pointer(), 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.
 */

static inline unsigned long
____cmpxchg_u8(volatile char *m, unsigned char old, unsigned char new)
{
        unsigned long prev, tmp, cmp, addr64;

        __asm__ __volatile__(
        "       andnot  %5,7,%4\n"
        "       insbl   %1,%5,%1\n"
        "1:     ldq_l   %2,0(%4)\n"
        "       extbl   %2,%5,%0\n"
        "       cmpeq   %0,%6,%3\n"
        "       beq     %3,2f\n"
        "       mskbl   %2,%5,%2\n"
        "       or      %1,%2,%2\n"
        "       stq_c   %2,0(%4)\n"
        "       beq     %2,3f\n"
        "2:\n"
        ".subsection 2\n"
        "3:     br      1b\n"
        ".previous"
        : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
        : "r" ((long)m), "Ir" (old), "1" (new) : "memory");

        return prev;
}

static inline unsigned long
____cmpxchg_u16(volatile short *m, unsigned short old, unsigned short new)
{
        unsigned long prev, tmp, cmp, addr64;

        __asm__ __volatile__(
        "       andnot  %5,7,%4\n"
        "       inswl   %1,%5,%1\n"
        "1:     ldq_l   %2,0(%4)\n"
        "       extwl   %2,%5,%0\n"
        "       cmpeq   %0,%6,%3\n"
        "       beq     %3,2f\n"
        "       mskwl   %2,%5,%2\n"
        "       or      %1,%2,%2\n"
        "       stq_c   %2,0(%4)\n"
        "       beq     %2,3f\n"
        "2:\n"
        ".subsection 2\n"
        "3:     br      1b\n"
        ".previous"
        : "=&r" (prev), "=&r" (new), "=&r" (tmp), "=&r" (cmp), "=&r" (addr64)
        : "r" ((long)m), "Ir" (old), "1" (new) : "memory");

        return prev;
}

static inline unsigned long
____cmpxchg_u32(volatile int *m, int old, int new)
{
        unsigned long prev, cmp;

        __asm__ __volatile__(
        "1:     ldl_l %0,%5\n"
        "       cmpeq %0,%3,%1\n"
        "       beq %1,2f\n"
        "       mov %4,%1\n"
        "       stl_c %1,%2\n"
        "       beq %1,3f\n"
        "2:\n"
        ".subsection 2\n"
        "3:     br 1b\n"
        ".previous"
        : "=&r"(prev), "=&r"(cmp), "=m"(*m)
        : "r"((long) old), "r"(new), "m"(*m) : "memory");

        return prev;
}

static inline unsigned long
____cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)
{
        unsigned long prev, cmp;

        __asm__ __volatile__(
        "1:     ldq_l %0,%5\n"
        "       cmpeq %0,%3,%1\n"
        "       beq %1,2f\n"
        "       mov %4,%1\n"
        "       stq_c %1,%2\n"
        "       beq %1,3f\n"
        "2:\n"
        ".subsection 2\n"
        "3:     br 1b\n"
        ".previous"
        : "=&r"(prev), "=&r"(cmp), "=m"(*m)
        : "r"((long) old), "r"(new), "m"(*m) : "memory");

        return prev;
}

/* 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 __always_inline unsigned long
____cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
              int size)
{
        return
                size == 1 ? ____cmpxchg_u8(ptr, old, new) :
                size == 2 ? ____cmpxchg_u16(ptr, old, new) :
                size == 4 ? ____cmpxchg_u32(ptr, old, new) :
                size == 8 ? ____cmpxchg_u64(ptr, old, new) :
                        (__cmpxchg_called_with_bad_pointer(), old);
}

#define xchg_local(ptr, x)                                              \
({                                                                      \
        __typeof__(*(ptr)) _x_ = (x);                                   \
        (__typeof__(*(ptr))) ____xchg((ptr), (unsigned long)_x_,        \
                                               sizeof(*(ptr)));         \
})

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

#define arch_cmpxchg64_local(ptr, o, n)                                 \
({                                                                      \
        BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
        cmpxchg_local((ptr), (o), (n));                                 \
})

/*
 * The leading and the trailing memory barriers guarantee that these
 * operations are fully ordered.
 */
#define arch_xchg(ptr, x)                                               \
({                                                                      \
        __typeof__(*(ptr)) __ret;                                       \
        __typeof__(*(ptr)) _x_ = (x);                                   \
        smp_mb();                                                       \
        __ret = (__typeof__(*(ptr)))                                    \
                ____xchg((ptr), (unsigned long)_x_, sizeof(*(ptr)));    \
        smp_mb();                                                       \
        __ret;                                                          \
})

#define arch_cmpxchg(ptr, o, n)                                         \
({                                                                      \
        __typeof__(*(ptr)) __ret;                                       \
        __typeof__(*(ptr)) _o_ = (o);                                   \
        __typeof__(*(ptr)) _n_ = (n);                                   \
        smp_mb();                                                       \
        __ret = (__typeof__(*(ptr))) ____cmpxchg((ptr),                 \
                (unsigned long)_o_, (unsigned long)_n_, sizeof(*(ptr)));\
        smp_mb();                                                       \
        __ret;                                                          \
})

#define arch_cmpxchg64(ptr, o, n)                                       \
({                                                                      \
        BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
        arch_cmpxchg((ptr), (o), (n));                                  \
})

#endif /* _ALPHA_CMPXCHG_H */