futex.h

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#ifndef _ASM_FUTEX_H
#define _ASM_FUTEX_H

#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>

#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
do {                                    \
    register unsigned long r8 __asm ("r8") = 0;         \
    __asm__ __volatile__(                       \
        "   mf;;                    \n" \
        "[1:] " insn ";;                \n" \
        "   .xdata4 \"__ex_table\", 1b-., 2f-.  \n" \
        "[2:]"                          \
        : "+r" (r8), "=r" (oldval)              \
        : "r" (uaddr), "r" (oparg)              \
        : "memory");                        \
    ret = r8;                           \
} while (0)

#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
do {                                    \
    register unsigned long r8 __asm ("r8") = 0;         \
    int val, newval;                        \
    do {                                \
        __asm__ __volatile__(                   \
            "   mf;;                  \n"   \
            "[1:]   ld4 %3=[%4];;             \n"   \
            "   mov %2=%3             \n"   \
                insn    ";;           \n"   \
            "   mov ar.ccv=%2;;           \n"   \
            "[2:]   cmpxchg4.acq %1=[%4],%3,ar.ccv;;  \n"   \
            "   .xdata4 \"__ex_table\", 1b-., 3f-.\n"   \
            "   .xdata4 \"__ex_table\", 2b-., 3f-.\n"   \
            "[3:]"                      \
            : "+r" (r8), "=r" (val), "=&r" (oldval),    \
               "=&r" (newval)               \
            : "r" (uaddr), "r" (oparg)          \
            : "memory");                    \
        if (unlikely (r8))                  \
            break;                      \
    } while (unlikely (val != oldval));             \
    ret = r8;                           \
} while (0)

static inline int
futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
{
    int op = (encoded_op >> 28) & 7;
    int cmp = (encoded_op >> 24) & 15;
    int oparg = (encoded_op << 8) >> 20;
    int cmparg = (encoded_op << 20) >> 20;
    int oldval = 0, ret;
    if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
        oparg = 1 << oparg;

    if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
        return -EFAULT;

    pagefault_disable();

    switch (op) {
    case FUTEX_OP_SET:
        __futex_atomic_op1("xchg4 %1=[%2],%3", ret, oldval, uaddr,
                   oparg);
        break;
    case FUTEX_OP_ADD:
        __futex_atomic_op2("add %3=%3,%5", ret, oldval, uaddr, oparg);
        break;
    case FUTEX_OP_OR:
        __futex_atomic_op2("or %3=%3,%5", ret, oldval, uaddr, oparg);
        break;
    case FUTEX_OP_ANDN:
        __futex_atomic_op2("and %3=%3,%5", ret, oldval, uaddr,
                   ~oparg);
        break;
    case FUTEX_OP_XOR:
        __futex_atomic_op2("xor %3=%3,%5", ret, oldval, uaddr, oparg);
        break;
    default:
        ret = -ENOSYS;
    }

    pagefault_enable();

    if (!ret) {
        switch (cmp) {
        case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
        case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
        case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
        case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
        case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
        case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
        default: ret = -ENOSYS;
        }
    }
    return ret;
}

static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
                  u32 oldval, u32 newval)
{
    if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
        return -EFAULT;

    {
        register unsigned long r8 __asm ("r8");
        unsigned long prev;
        __asm__ __volatile__(
            "   mf;;                    \n"
            "   mov %0=r0               \n"
            "   mov ar.ccv=%4;;             \n"
            "[1:]   cmpxchg4.acq %1=[%2],%3,ar.ccv      \n"
            "   .xdata4 \"__ex_table\", 1b-., 2f-.  \n"
            "[2:]"
            : "=r" (r8), "=r" (prev)
            : "r" (uaddr), "r" (newval),
              "rO" ((long) (unsigned) oldval)
            : "memory");
        *uval = prev;
        return r8;
    }
}

#endif /* _ASM_FUTEX_H */