/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * OpenRISC Linux
 *
 * Linux architectural port borrowing liberally from similar works of
 * others.  All original copyrights apply as per the original source
 * declaration.
 *
 * OpenRISC implementation:
 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 * et al.
 */

#ifndef __ASM_OPENRISC_UACCESS_H
#define __ASM_OPENRISC_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/prefetch.h>
#include <linux/string.h>
#include <asm/page.h>
#include <asm/extable.h>
#include <asm-generic/access_ok.h>

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 *
 * This gets kind of ugly. We want to return _two_ values in "get_user()"
 * and yet we don't want to do any pointers, because that is too much
 * of a performance impact. Thus we have a few rather ugly macros here,
 * and hide all the uglyness from the user.
 *
 * The "__xxx" versions of the user access functions are versions that
 * do not verify the address space, that must have been done previously
 * with a separate "access_ok()" call (this is used when we do multiple
 * accesses to the same area of user memory).
 *
 * As we use the same address space for kernel and user data on the
 * PowerPC, we can just do these as direct assignments.  (Of course, the
 * exception handling means that it's no longer "just"...)
 */
#define get_user(x, ptr) \
        __get_user_check((x), (ptr), sizeof(*(ptr)))
#define put_user(x, ptr) \
        __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

#define __get_user(x, ptr) \
        __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
#define __put_user(x, ptr) \
        __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

extern long __put_user_bad(void);

#define __put_user_nocheck(x, ptr, size)                \
({                                                      \
        long __pu_err;                                  \
        __put_user_size((x), (ptr), (size), __pu_err);  \
        __pu_err;                                       \
})

#define __put_user_check(x, ptr, size)                                  \
({                                                                      \
        long __pu_err = -EFAULT;                                        \
        __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
        if (access_ok(__pu_addr, size))                 \
                __put_user_size((x), __pu_addr, (size), __pu_err);      \
        __pu_err;                                                       \
})

#define __put_user_size(x, ptr, size, retval)                           \
do {                                                                    \
        retval = 0;                                                     \
        switch (size) {                                                 \
        case 1: __put_user_asm(x, ptr, retval, "l.sb"); break;          \
        case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;          \
        case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;          \
        case 8: __put_user_asm2(x, ptr, retval); break;                 \
        default: __put_user_bad();                                      \
        }                                                               \
} while (0)

struct __large_struct {
        unsigned long buf[100];
};
#define __m(x) (*(struct __large_struct *)(x))

/*
 * We don't tell gcc that we are accessing memory, but this is OK
 * because we do not write to any memory gcc knows about, so there
 * are no aliasing issues.
 */
#define __put_user_asm(x, addr, err, op)                        \
        __asm__ __volatile__(                                   \
                "1:     "op" 0(%2),%1\n"                        \
                "2:\n"                                          \
                ".section .fixup,\"ax\"\n"                      \
                "3:     l.addi %0,r0,%3\n"                      \
                "       l.j 2b\n"                               \
                "       l.nop\n"                                \
                ".previous\n"                                   \
                ".section __ex_table,\"a\"\n"                   \
                "       .align 2\n"                             \
                "       .long 1b,3b\n"                          \
                ".previous"                                     \
                : "=r"(err)                                     \
                : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))

#define __put_user_asm2(x, addr, err)                           \
        __asm__ __volatile__(                                   \
                "1:     l.sw 0(%2),%1\n"                        \
                "2:     l.sw 4(%2),%H1\n"                       \
                "3:\n"                                          \
                ".section .fixup,\"ax\"\n"                      \
                "4:     l.addi %0,r0,%3\n"                      \
                "       l.j 3b\n"                               \
                "       l.nop\n"                                \
                ".previous\n"                                   \
                ".section __ex_table,\"a\"\n"                   \
                "       .align 2\n"                             \
                "       .long 1b,4b\n"                          \
                "       .long 2b,4b\n"                          \
                ".previous"                                     \
                : "=r"(err)                                     \
                : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))

#define __get_user_nocheck(x, ptr, size)                        \
({                                                              \
        long __gu_err;                                          \
        __get_user_size((x), (ptr), (size), __gu_err);          \
        __gu_err;                                               \
})

#define __get_user_check(x, ptr, size)                                  \
({                                                                      \
        long __gu_err = -EFAULT;                                        \
        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
        if (access_ok(__gu_addr, size))                                 \
                __get_user_size((x), __gu_addr, (size), __gu_err);      \
        else                                                            \
                (x) = (__typeof__(*(ptr))) 0;                           \
        __gu_err;                                                       \
})

extern long __get_user_bad(void);

#define __get_user_size(x, ptr, size, retval)                           \
do {                                                                    \
        retval = 0;                                                     \
        switch (size) {                                                 \
        case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break;         \
        case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;         \
        case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;         \
        case 8: __get_user_asm2(x, ptr, retval); break;                 \
        default: (x) = (__typeof__(*(ptr)))__get_user_bad();            \
        }                                                               \
} while (0)

#define __get_user_asm(x, addr, err, op)                \
{                                                       \
        unsigned long __gu_tmp;                         \
        __asm__ __volatile__(                           \
                "1:     "op" %1,0(%2)\n"                \
                "2:\n"                                  \
                ".section .fixup,\"ax\"\n"              \
                "3:     l.addi %0,r0,%3\n"              \
                "       l.addi %1,r0,0\n"               \
                "       l.j 2b\n"                       \
                "       l.nop\n"                        \
                ".previous\n"                           \
                ".section __ex_table,\"a\"\n"           \
                "       .align 2\n"                     \
                "       .long 1b,3b\n"                  \
                ".previous"                             \
                : "=r"(err), "=r"(__gu_tmp)             \
                : "r"(addr), "i"(-EFAULT), "0"(err));   \
        (x) = (__typeof__(*(addr)))__gu_tmp;            \
}

#define __get_user_asm2(x, addr, err)                   \
{                                                       \
        unsigned long long __gu_tmp;                    \
        __asm__ __volatile__(                           \
                "1:     l.lwz %1,0(%2)\n"               \
                "2:     l.lwz %H1,4(%2)\n"              \
                "3:\n"                                  \
                ".section .fixup,\"ax\"\n"              \
                "4:     l.addi %0,r0,%3\n"              \
                "       l.addi %1,r0,0\n"               \
                "       l.addi %H1,r0,0\n"              \
                "       l.j 3b\n"                       \
                "       l.nop\n"                        \
                ".previous\n"                           \
                ".section __ex_table,\"a\"\n"           \
                "       .align 2\n"                     \
                "       .long 1b,4b\n"                  \
                "       .long 2b,4b\n"                  \
                ".previous"                             \
                : "=r"(err), "=&r"(__gu_tmp)            \
                : "r"(addr), "i"(-EFAULT), "0"(err));   \
        (x) = (__typeof__(*(addr)))(                    \
                (__typeof__((x)-(x)))__gu_tmp);         \
}

/* more complex routines */

extern unsigned long __must_check
__copy_tofrom_user(void *to, const void *from, unsigned long size);
static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long size)
{
        return __copy_tofrom_user(to, (__force const void *)from, size);
}
static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long size)
{
        return __copy_tofrom_user((__force void *)to, from, size);
}
#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER

extern unsigned long __clear_user(void __user *addr, unsigned long size);

static inline __must_check unsigned long
clear_user(void __user *addr, unsigned long size)
{
        if (likely(access_ok(addr, size)))
                size = __clear_user(addr, size);
        return size;
}

extern long strncpy_from_user(char *dest, const char __user *src, long count);

extern __must_check long strnlen_user(const char __user *str, long n);

#endif /* __ASM_OPENRISC_UACCESS_H */