/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_FUTEX_H
#define _ASM_X86_FUTEX_H

#ifdef __KERNEL__

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

#include <asm/asm.h>
#include <asm/errno.h>
#include <asm/processor.h>
#include <asm/smap.h>

#define unsafe_atomic_op1(insn, oval, uaddr, oparg, label)      \
do {                                                            \
        int oldval = 0, ret;                                    \
        asm volatile("1:\t" insn "\n"                           \
                     "2:\n"                                     \
                     _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %1) \
                     : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
                     : "0" (oparg), "1" (0));   \
        if (ret)                                                \
                goto label;                                     \
        *oval = oldval;                                         \
} while(0)


#define unsafe_atomic_op2(insn, oval, uaddr, oparg, label)      \
do {                                                            \
        int oldval = 0, ret, tem;                               \
        asm volatile("1:\tmovl  %2, %0\n"                       \
                     "2:\tmovl\t%0, %3\n"                       \
                     "\t" insn "\n"                             \
                     "3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"     \
                     "\tjnz\t2b\n"                              \
                     "4:\n"                                     \
                     _ASM_EXTABLE_TYPE_REG(1b, 4b, EX_TYPE_EFAULT_REG, %1) \
                     _ASM_EXTABLE_TYPE_REG(3b, 4b, EX_TYPE_EFAULT_REG, %1) \
                     : "=&a" (oldval), "=&r" (ret),             \
                       "+m" (*uaddr), "=&r" (tem)               \
                     : "r" (oparg), "1" (0));                   \
        if (ret)                                                \
                goto label;                                     \
        *oval = oldval;                                         \
} while(0)

static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
                                                       u32 __user *uaddr)
{
        scoped_user_rw_access(uaddr, Efault) {
                switch (op) {
                case FUTEX_OP_SET:
                        unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault);
                        break;
                case FUTEX_OP_ADD:
                        unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval, uaddr, oparg, Efault);
                        break;
                case FUTEX_OP_OR:
                        unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault);
                        break;
                case FUTEX_OP_ANDN:
                        unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault);
                        break;
                case FUTEX_OP_XOR:
                        unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault);
                        break;
                default:
                        return -ENOSYS;
                }
        }
        return 0;
Efault:
        return -EFAULT;
}

static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
                                                u32 oldval, u32 newval)
{
        int ret = 0;

        scoped_user_rw_access(uaddr, Efault) {
                asm_inline volatile("\n"
                                    "1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"
                                    "2:\n"
                                    _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0)
                                    : "+r" (ret), "=a" (oldval), "+m" (*uaddr)
                                    : "r" (newval), "1" (oldval)
                                    : "memory");
                *uval = oldval;
        }
        return ret;
Efault:
        return -EFAULT;
}

#endif
#endif /* _ASM_X86_FUTEX_H */