futex.h

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#ifndef _ASM_ALPHA_FUTEX_H
#define _ASM_ALPHA_FUTEX_H

#ifdef __KERNEL__

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

#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)  \
    __asm__ __volatile__(                   \
        __ASM_SMP_MB                    \
    "1: ldl_l   %0,0(%2)\n"             \
        insn                        \
    "2: stl_c   %1,0(%2)\n"             \
    "   beq %1,4f\n"                \
    "   mov $31,%1\n"               \
    "3: .subsection 2\n"                \
    "4: br  1b\n"                   \
    "   .previous\n"                    \
    "   .section __ex_table,\"a\"\n"            \
    "   .long   1b-.\n"                 \
    "   lda $31,3b-1b(%1)\n"            \
    "   .long   2b-.\n"                 \
    "   lda $31,3b-2b(%1)\n"            \
    "   .previous\n"                    \
    :   "=&r" (oldval), "=&r"(ret)          \
    :   "r" (uaddr), "r"(oparg)             \
    :   "memory")

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_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
        break;
    case FUTEX_OP_ADD:
        __futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
        break;
    case FUTEX_OP_OR:
        __futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
        break;
    case FUTEX_OP_ANDN:
        __futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
        break;
    case FUTEX_OP_XOR:
        __futex_atomic_op("xor %0,%3,%1\n", 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)
{
    int ret = 0, cmp;
    u32 prev;

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

    __asm__ __volatile__ (
        __ASM_SMP_MB
    "1: ldl_l   %1,0(%3)\n"
    "   cmpeq   %1,%4,%2\n"
    "   beq %2,3f\n"
    "   mov %5,%2\n"
    "2: stl_c   %2,0(%3)\n"
    "   beq %2,4f\n"
    "3: .subsection 2\n"
    "4: br  1b\n"
    "   .previous\n"
    "   .section __ex_table,\"a\"\n"
    "   .long   1b-.\n"
    "   lda $31,3b-1b(%0)\n"
    "   .long   2b-.\n"
    "   lda $31,3b-2b(%0)\n"
    "   .previous\n"
    :   "+r"(ret), "=&r"(prev), "=&r"(cmp)
    :   "r"(uaddr), "r"((long)(int)oldval), "r"(newval)
    :   "memory");

    *uval = prev;
    return ret;
}

#endif /* __KERNEL__ */
#endif /* _ASM_ALPHA_FUTEX_H */