/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 *
 * Derived from MIPS:
 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2007  Maciej W. Rozycki
 * Copyright (C) 2014, Imagination Technologies Ltd.
 */
#ifndef _ASM_UACCESS_H
#define _ASM_UACCESS_H

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/extable.h>
#include <asm/pgtable.h>
#include <asm/extable.h>
#include <asm/asm-extable.h>
#include <asm-generic/access_ok.h>

#define __LSW   0
#define __MSW   1

extern u64 __ua_limit;

#ifdef CONFIG_64BIT
#define __UA_LIMIT      __ua_limit
#else
#define __UA_LIMIT      0x80000000UL
#endif

/*
 * get_user: - Get a simple variable from user space.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define get_user(x, ptr) \
({                                                                      \
        const __typeof__(*(ptr)) __user *__p = (ptr);                   \
                                                                        \
        might_fault();                                                  \
        access_ok(__p, sizeof(*__p)) ? __get_user((x), __p) :           \
                                       ((x) = 0, -EFAULT);              \
})

/*
 * put_user: - Write a simple value into user space.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define put_user(x, ptr) \
({                                                                      \
        __typeof__(*(ptr)) __user *__p = (ptr);                         \
                                                                        \
        might_fault();                                                  \
        access_ok(__p, sizeof(*__p)) ? __put_user((x), __p) : -EFAULT;  \
})

/*
 * __get_user: - Get a simple variable from user space, with less checking.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define __get_user(x, ptr) \
({                                                                      \
        int __gu_err = 0;                                               \
                                                                        \
        __chk_user_ptr(ptr);                                            \
        __get_user_common((x), sizeof(*(ptr)), ptr);                    \
        __gu_err;                                                       \
})

/*
 * __put_user: - Write a simple value into user space, with less checking.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 */

#define __put_user(x, ptr) \
({                                                                      \
        int __pu_err = 0;                                               \
        __typeof__(*(ptr)) __pu_val;                                    \
                                                                        \
        __pu_val = (x);                                                 \
        __chk_user_ptr(ptr);                                            \
        __put_user_common(ptr, sizeof(*(ptr)));                         \
        __pu_err;                                                       \
})

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

#define __get_user_common(val, size, ptr)                               \
do {                                                                    \
        switch (size) {                                                 \
        case 1: __get_data_asm(val, "ld.b", ptr); break;                \
        case 2: __get_data_asm(val, "ld.h", ptr); break;                \
        case 4: __get_data_asm(val, "ld.w", ptr); break;                \
        case 8: __get_data_asm_8(val, ptr); break;                      \
        default: BUILD_BUG(); break;                                    \
        }                                                               \
} while (0)

#define __get_kernel_common(val, size, ptr) __get_user_common(val, size, ptr)

#define __get_data_asm(val, insn, ptr)                                  \
{                                                                       \
        long __gu_tmp;                                                  \
                                                                        \
        __asm__ __volatile__(                                           \
        "1:     " insn "        %1, %2                          \n"     \
        "2:                                                     \n"     \
        _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %0, %1)                   \
        : "+r" (__gu_err), "=r" (__gu_tmp)                              \
        : "m" (__m(ptr)));                                              \
                                                                        \
        (val) = (__typeof__(*(ptr))) __gu_tmp;                          \
}

#ifdef CONFIG_64BIT
#define __get_data_asm_8(val, ptr) \
        __get_data_asm(val, "ld.d", ptr)
#else /* !CONFIG_64BIT */
#define __get_data_asm_8(val, ptr)                                      \
{                                                                       \
        u32 __lo, __hi;                                                 \
        u32 __user *__ptr = (u32 __user *)(ptr);                        \
                                                                        \
        __asm__ __volatile__ (                                          \
                "1:\n"                                                  \
                "       ld.w %1, %3                             \n"     \
                "2:\n"                                                  \
                "       ld.w %2, %4                             \n"     \
                "3:\n"                                                  \
                _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 3b, %0, %1)           \
                _ASM_EXTABLE_UACCESS_ERR_ZERO(2b, 3b, %0, %1)           \
                : "+r" (__gu_err), "=&r" (__lo), "=r" (__hi)            \
                : "m" (__ptr[__LSW]), "m" (__ptr[__MSW]));              \
        if (__gu_err)                                                   \
                __hi = 0;                                               \
        (val) = (__typeof__(val))((__typeof__((val)-(val)))             \
                ((((u64)__hi << 32) | __lo)));                          \
}
#endif /* CONFIG_64BIT */

#define __put_user_common(ptr, size)                                    \
do {                                                                    \
        switch (size) {                                                 \
        case 1: __put_data_asm("st.b", ptr); break;                     \
        case 2: __put_data_asm("st.h", ptr); break;                     \
        case 4: __put_data_asm("st.w", ptr); break;                     \
        case 8: __put_data_asm_8(ptr); break;                           \
        default: BUILD_BUG(); break;                                    \
        }                                                               \
} while (0)

#define __put_kernel_common(ptr, size) __put_user_common(ptr, size)

#define __put_data_asm(insn, ptr)                                       \
{                                                                       \
        __asm__ __volatile__(                                           \
        "1:     " insn "        %z2, %1         # __put_user_asm\n"     \
        "2:                                                     \n"     \
        _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %0)                            \
        : "+r" (__pu_err), "=m" (__m(ptr))                              \
        : "Jr" (__pu_val));                                             \
}

#ifdef CONFIG_64BIT
#define __put_data_asm_8(ptr) \
        __put_data_asm("st.d", ptr)
#else /* !CONFIG_64BIT */
#define __put_data_asm_8(ptr)                                           \
{                                                                       \
        u32 __user *__ptr = (u32 __user *)(ptr);                        \
        u64 __x = (__typeof__((__pu_val)-(__pu_val)))(__pu_val);        \
                                                                        \
        __asm__ __volatile__ (                                          \
                "1:\n"                                                  \
                "       st.w %z3, %1                            \n"     \
                "2:\n"                                                  \
                "       st.w %z4, %2                            \n"     \
                "3:\n"                                                  \
                _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0)                    \
                _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0)                    \
                : "+r" (__pu_err),                                      \
                        "=m" (__ptr[__LSW]),                            \
                        "=m" (__ptr[__MSW])                             \
                : "rJ" (__x), "rJ" (__x >> 32));                        \
}
#endif /* CONFIG_64BIT */

#define __get_kernel_nofault(dst, src, type, err_label)                 \
do {                                                                    \
        int __gu_err = 0;                                               \
                                                                        \
        __get_kernel_common(*((type *)(dst)), sizeof(type),             \
                            (__force type *)(src));                     \
        if (unlikely(__gu_err)) {                                       \
                pr_info("%s: memory access failed, ecode 0x%x\n",       \
                        __func__, read_csr_excode());                   \
                pr_info("%s: the caller is %pS\n",                      \
                        __func__, __builtin_return_address(0));         \
                goto err_label;                                         \
        }                                                               \
} while (0)

#define __put_kernel_nofault(dst, src, type, err_label)                 \
do {                                                                    \
        type __pu_val;                                                  \
        int __pu_err = 0;                                               \
                                                                        \
        __pu_val = *(__force type *)(src);                              \
        __put_kernel_common(((type *)(dst)), sizeof(type));             \
        if (unlikely(__pu_err)) {                                       \
                pr_info("%s: memory access failed, ecode 0x%x\n",       \
                        __func__, read_csr_excode());                   \
                pr_info("%s: the caller is %pS\n",                      \
                        __func__, __builtin_return_address(0));         \
                goto err_label;                                         \
        }                                                               \
} while (0)

extern unsigned long __copy_user(void *to, const void *from, __kernel_size_t n);

static inline unsigned long __must_check
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
{
        return __copy_user(to, (__force const void *)from, n);
}

static inline unsigned long __must_check
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
{
        return __copy_user((__force void *)to, from, n);
}

#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER

/*
 * __clear_user: - Zero a block of memory in user space, with less checking.
 * @addr: Destination address, in user space.
 * @size: Number of bytes to zero.
 *
 * Zero a block of memory in user space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be cleared.
 * On success, this will be zero.
 */
extern unsigned long __clear_user(void __user *addr, __kernel_size_t size);

#define clear_user(addr, n)                                             \
({                                                                      \
        void __user *__cl_addr = (addr);                                \
        unsigned long __cl_size = (n);                                  \
        if (__cl_size && access_ok(__cl_addr, __cl_size))               \
                __cl_size = __clear_user(__cl_addr, __cl_size);         \
        __cl_size;                                                      \
})

extern long strncpy_from_user(char *to, const char __user *from, long n);
extern long strnlen_user(const char __user *str, long n);

#endif /* _ASM_UACCESS_H */