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

#ifdef __KERNEL__

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

/* XXX TODO-- need to add sync barriers! */

#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
        __asm__ __volatile( \
        "1: %0 = memw_locked(%3);\n" \
            /* For example: %1 = %4 */ \
            insn \
        "2: memw_locked(%3,p2) = %1;\n" \
        "   if (!p2) jump 1b;\n" \
        "   %1 = #0;\n" \
        "3:\n" \
        ".section .fixup,\"ax\"\n" \
        "4: %1 = #%5;\n" \
        "   jump ##3b\n" \
        ".previous\n" \
        ".section __ex_table,\"a\"\n" \
        ".long 1b,4b,2b,4b\n" \
        ".previous\n" \
        : "=&r" (oldval), "=&r" (ret), "+m" (*uaddr) \
        : "r" (uaddr), "r" (oparg), "i" (-EFAULT) \
        : "p2", "memory")


static inline int
arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
{
        int oldval = 0, ret;

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

        switch (op) {
        case FUTEX_OP_SET:
                __futex_atomic_op("%1 = %4\n", ret, oldval, uaddr, oparg);
                break;
        case FUTEX_OP_ADD:
                __futex_atomic_op("%1 = add(%0,%4)\n", ret, oldval, uaddr,
                                  oparg);
                break;
        case FUTEX_OP_OR:
                __futex_atomic_op("%1 = or(%0,%4)\n", ret, oldval, uaddr,
                                  oparg);
                break;
        case FUTEX_OP_ANDN:
                __futex_atomic_op("%1 = not(%4); %1 = and(%0,%1)\n", ret,
                                  oldval, uaddr, oparg);
                break;
        case FUTEX_OP_XOR:
                __futex_atomic_op("%1 = xor(%0,%4)\n", ret, oldval, uaddr,
                                  oparg);
                break;
        default:
                ret = -ENOSYS;
        }

        if (!ret)
                *oval = oldval;

        return ret;
}

static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
                              u32 newval)
{
        int prev;
        int ret;

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

        __asm__ __volatile__ (
        "1: %1 = memw_locked(%3)\n"
        "   {\n"
        "      p2 = cmp.eq(%1,%4)\n"
        "      if (!p2.new) jump:NT 3f\n"
        "   }\n"
        "2: memw_locked(%3,p2) = %5\n"
        "   if (!p2) jump 1b\n"
        "3:\n"
        ".section .fixup,\"ax\"\n"
        "4: %0 = #%6\n"
        "   jump ##3b\n"
        ".previous\n"
        ".section __ex_table,\"a\"\n"
        ".long 1b,4b,2b,4b\n"
        ".previous\n"
        : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
        : "r" (uaddr), "r" (oldval), "r" (newval), "i"(-EFAULT)
        : "p2", "memory");

        *uval = prev;
        return ret;
}

#endif /* __KERNEL__ */
#endif /* _ASM_HEXAGON_FUTEX_H */