/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * 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 <asm/asm-eva.h>
#include <asm/extable.h>

#ifdef CONFIG_32BIT

#define __UA_LIMIT 0x80000000UL

#define __UA_ADDR       ".word"
#define __UA_LA         "la"
#define __UA_ADDU       "addu"
#define __UA_t0         "$8"
#define __UA_t1         "$9"

#endif /* CONFIG_32BIT */

#ifdef CONFIG_64BIT

extern u64 __ua_limit;

#define __UA_LIMIT      __ua_limit

#define __UA_ADDR       ".dword"
#define __UA_LA         "dla"
#define __UA_ADDU       "daddu"
#define __UA_t0         "$12"
#define __UA_t1         "$13"

#endif /* CONFIG_64BIT */

/*
 * Is a address valid? This does a straightforward calculation rather
 * than tests.
 *
 * Address valid if:
 *  - "addr" doesn't have any high-bits set
 *  - AND "size" doesn't have any high-bits set
 *  - AND "addr+size" doesn't have any high-bits set
 *  - OR we are in kernel mode.
 *
 * __ua_size() is a trick to avoid runtime checking of positive constant
 * sizes; for those we already know at compile time that the size is ok.
 */
#define __ua_size(size)                                                 \
        ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))

/*
 * access_ok: - Checks if a user space pointer is valid
 * @addr: User space pointer to start of block to check
 * @size: Size of block to check
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * Checks if a pointer to a block of memory in user space is valid.
 *
 * Returns true (nonzero) if the memory block may be valid, false (zero)
 * if it is definitely invalid.
 *
 * Note that, depending on architecture, this function probably just
 * checks that the pointer is in the user space range - after calling
 * this function, memory access functions may still return -EFAULT.
 */

static inline int __access_ok(const void __user *p, unsigned long size)
{
        unsigned long addr = (unsigned long)p;
        unsigned long end = addr + size - !!size;

        return (__UA_LIMIT & (addr | end | __ua_size(size))) == 0;
}

#define access_ok(addr, size)                                   \
        likely(__access_ok((addr), (size)))

/*
 * 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.
 * @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, 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)                                              \
({                                                                      \
        __typeof__(*(ptr)) __user *__pu_ptr = (ptr);                    \
        __typeof__(*(ptr)) __pu_val = (x);                              \
        int __pu_err = 0;                                               \
                                                                        \
        __chk_user_ptr(__pu_ptr);                                       \
        switch (sizeof(*__pu_ptr)) {                                    \
        case 1:                                                         \
                __put_data_asm(user_sb, __pu_ptr);                      \
                break;                                                  \
        case 2:                                                         \
                __put_data_asm(user_sh, __pu_ptr);                      \
                break;                                                  \
        case 4:                                                         \
                __put_data_asm(user_sw, __pu_ptr);                      \
                break;                                                  \
        case 8:                                                         \
                __PUT_DW(user_sd, __pu_ptr);                            \
                break;                                                  \
        default:                                                        \
                BUILD_BUG();                                            \
        }                                                               \
                                                                        \
        __pu_err;                                                       \
})

/*
 * __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)                                              \
({                                                                      \
        const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);              \
        int __gu_err = 0;                                               \
                                                                        \
        __chk_user_ptr(__gu_ptr);                                       \
        switch (sizeof(*__gu_ptr)) {                                    \
        case 1:                                                         \
                __get_data_asm((x), user_lb, __gu_ptr);                 \
                break;                                                  \
        case 2:                                                         \
                __get_data_asm((x), user_lh, __gu_ptr);                 \
                break;                                                  \
        case 4:                                                         \
                __get_data_asm((x), user_lw, __gu_ptr);                 \
                break;                                                  \
        case 8:                                                         \
                __GET_DW((x), user_ld, __gu_ptr);                       \
                break;                                                  \
        default:                                                        \
                BUILD_BUG();                                            \
        }                                                               \
                                                                        \
        __gu_err;                                                       \
})

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

#ifdef CONFIG_32BIT
#define __GET_DW(val, insn, ptr) __get_data_asm_ll32(val, insn, ptr)
#endif
#ifdef CONFIG_64BIT
#define __GET_DW(val, insn, ptr) __get_data_asm(val, insn, ptr)
#endif

#define __get_data_asm(val, insn, addr)                                 \
{                                                                       \
        long __gu_tmp;                                                  \
                                                                        \
        __asm__ __volatile__(                                           \
        "1:     "insn("%1", "%3")"                              \n"     \
        "2:                                                     \n"     \
        "       .insn                                           \n"     \
        "       .section .fixup,\"ax\"                          \n"     \
        "3:     li      %0, %4                                  \n"     \
        "       move    %1, $0                                  \n"     \
        "       j       2b                                      \n"     \
        "       .previous                                       \n"     \
        "       .section __ex_table,\"a\"                       \n"     \
        "       "__UA_ADDR "\t1b, 3b                            \n"     \
        "       .previous                                       \n"     \
        : "=r" (__gu_err), "=r" (__gu_tmp)                              \
        : "0" (0), "o" (__m(addr)), "i" (-EFAULT));                     \
                                                                        \
        (val) = (__typeof__(*(addr))) __gu_tmp;                         \
}

/*
 * Get a long long 64 using 32 bit registers.
 */
#define __get_data_asm_ll32(val, insn, addr)                            \
{                                                                       \
        union {                                                         \
                unsigned long long      l;                              \
                __typeof__(*(addr))     t;                              \
        } __gu_tmp;                                                     \
                                                                        \
        __asm__ __volatile__(                                           \
        "1:     " insn("%1", "(%3)")"                           \n"     \
        "2:     " insn("%D1", "4(%3)")"                         \n"     \
        "3:                                                     \n"     \
        "       .insn                                           \n"     \
        "       .section        .fixup,\"ax\"                   \n"     \
        "4:     li      %0, %4                                  \n"     \
        "       move    %1, $0                                  \n"     \
        "       move    %D1, $0                                 \n"     \
        "       j       3b                                      \n"     \
        "       .previous                                       \n"     \
        "       .section        __ex_table,\"a\"                \n"     \
        "       " __UA_ADDR "   1b, 4b                          \n"     \
        "       " __UA_ADDR "   2b, 4b                          \n"     \
        "       .previous                                       \n"     \
        : "=r" (__gu_err), "=&r" (__gu_tmp.l)                           \
        : "0" (0), "r" (addr), "i" (-EFAULT));                          \
                                                                        \
        (val) = __gu_tmp.t;                                             \
}

#define HAVE_GET_KERNEL_NOFAULT

#define __get_kernel_nofault(dst, src, type, err_label)                 \
do {                                                                    \
        int __gu_err;                                                   \
                                                                        \
        switch (sizeof(type)) {                                         \
        case 1:                                                         \
                __get_data_asm(*(type *)(dst), kernel_lb,               \
                               (__force type *)(src));                  \
                break;                                                  \
        case 2:                                                         \
                __get_data_asm(*(type *)(dst), kernel_lh,               \
                               (__force type *)(src));                  \
                break;                                                  \
        case 4:                                                         \
                 __get_data_asm(*(type *)(dst), kernel_lw,              \
                               (__force type *)(src));                  \
                break;                                                  \
        case 8:                                                         \
                __GET_DW(*(type *)(dst), kernel_ld,                     \
                         (__force type *)(src));                        \
                break;                                                  \
        default:                                                        \
                BUILD_BUG();                                            \
                break;                                                  \
        }                                                               \
        if (unlikely(__gu_err))                                         \
                goto err_label;                                         \
} while (0)

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
#ifdef CONFIG_32BIT
#define __PUT_DW(insn, ptr) __put_data_asm_ll32(insn, ptr)
#endif
#ifdef CONFIG_64BIT
#define __PUT_DW(insn, ptr) __put_data_asm(insn, ptr)
#endif

#define __put_data_asm(insn, ptr)                                       \
{                                                                       \
        __asm__ __volatile__(                                           \
        "1:     "insn("%z2", "%3")"     # __put_data_asm        \n"     \
        "2:                                                     \n"     \
        "       .insn                                           \n"     \
        "       .section        .fixup,\"ax\"                   \n"     \
        "3:     li      %0, %4                                  \n"     \
        "       j       2b                                      \n"     \
        "       .previous                                       \n"     \
        "       .section        __ex_table,\"a\"                \n"     \
        "       " __UA_ADDR "   1b, 3b                          \n"     \
        "       .previous                                       \n"     \
        : "=r" (__pu_err)                                               \
        : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)),                     \
          "i" (-EFAULT));                                               \
}

#define __put_data_asm_ll32(insn, ptr)                                  \
{                                                                       \
        __asm__ __volatile__(                                           \
        "1:     "insn("%2", "(%3)")"    # __put_data_asm_ll32   \n"     \
        "2:     "insn("%D2", "4(%3)")"                          \n"     \
        "3:                                                     \n"     \
        "       .insn                                           \n"     \
        "       .section        .fixup,\"ax\"                   \n"     \
        "4:     li      %0, %4                                  \n"     \
        "       j       3b                                      \n"     \
        "       .previous                                       \n"     \
        "       .section        __ex_table,\"a\"                \n"     \
        "       " __UA_ADDR "   1b, 4b                          \n"     \
        "       " __UA_ADDR "   2b, 4b                          \n"     \
        "       .previous"                                              \
        : "=r" (__pu_err)                                               \
        : "0" (0), "r" (__pu_val), "r" (ptr),                           \
          "i" (-EFAULT));                                               \
}

#define __put_kernel_nofault(dst, src, type, err_label)                 \
do {                                                                    \
        type __pu_val;                                  \
        int __pu_err = 0;                                               \
                                                                        \
        __pu_val = *(__force type *)(src);                              \
        switch (sizeof(type)) {                                         \
        case 1:                                                         \
                __put_data_asm(kernel_sb, (type *)(dst));               \
                break;                                                  \
        case 2:                                                         \
                __put_data_asm(kernel_sh, (type *)(dst));               \
                break;                                                  \
        case 4:                                                         \
                __put_data_asm(kernel_sw, (type *)(dst))                \
                break;                                                  \
        case 8:                                                         \
                __PUT_DW(kernel_sd, (type *)(dst));                     \
                break;                                                  \
        default:                                                        \
                BUILD_BUG();                                            \
                break;                                                  \
        }                                                               \
        if (unlikely(__pu_err))                                         \
                goto err_label;                                         \
} while (0)


/*
 * We're generating jump to subroutines which will be outside the range of
 * jump instructions
 */
#ifdef MODULE
#define __MODULE_JAL(destination)                                       \
        ".set\tnoat\n\t"                                                \
        __UA_LA "\t$1, " #destination "\n\t"                            \
        "jalr\t$1\n\t"                                                  \
        ".set\tat\n\t"
#else
#define __MODULE_JAL(destination)                                       \
        "jal\t" #destination "\n\t"
#endif

#if defined(CONFIG_CPU_DADDI_WORKAROUNDS) || (defined(CONFIG_EVA) &&    \
                                              defined(CONFIG_CPU_HAS_PREFETCH))
#define DADDI_SCRATCH "$3"
#else
#define DADDI_SCRATCH "$0"
#endif

extern size_t __raw_copy_from_user(void *__to, const void *__from, size_t __n);
extern size_t __raw_copy_to_user(void *__to, const void *__from, size_t __n);
extern size_t __raw_copy_in_user(void *__to, const void *__from, size_t __n);

static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
{
        register void *__cu_to_r __asm__("$4");
        register const void __user *__cu_from_r __asm__("$5");
        register long __cu_len_r __asm__("$6");

        __cu_to_r = to;
        __cu_from_r = from;
        __cu_len_r = n;

        __asm__ __volatile__(
                ".set\tnoreorder\n\t"
                __MODULE_JAL(__raw_copy_from_user)
                ".set\tnoat\n\t"
                __UA_ADDU "\t$1, %1, %2\n\t"
                ".set\tat\n\t"
                ".set\treorder"
                : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)
                :
                : "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31",
                  DADDI_SCRATCH, "memory");

        return __cu_len_r;
}

static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
{
        register void __user *__cu_to_r __asm__("$4");
        register const void *__cu_from_r __asm__("$5");
        register long __cu_len_r __asm__("$6");

        __cu_to_r = (to);
        __cu_from_r = (from);
        __cu_len_r = (n);

        __asm__ __volatile__(
                __MODULE_JAL(__raw_copy_to_user)
                : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)
                :
                : "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31",
                  DADDI_SCRATCH, "memory");

        return __cu_len_r;
}

#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER

static inline unsigned long
raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
        register void __user *__cu_to_r __asm__("$4");
        register const void __user *__cu_from_r __asm__("$5");
        register long __cu_len_r __asm__("$6");

        __cu_to_r = to;
        __cu_from_r = from;
        __cu_len_r = n;

        __asm__ __volatile__(
                ".set\tnoreorder\n\t"
                __MODULE_JAL(__raw_copy_in_user)
                ".set\tnoat\n\t"
                __UA_ADDU "\t$1, %1, %2\n\t"
                ".set\tat\n\t"
                ".set\treorder"
                : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)
                :
                : "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31",
                  DADDI_SCRATCH, "memory");
        return __cu_len_r;
}

extern __kernel_size_t __bzero(void __user *addr, __kernel_size_t size);

/*
 * __clear_user: - Zero a block of memory in user space, with less checking.
 * @to:   Destination address, in user space.
 * @n:    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.
 */
static inline __kernel_size_t
__clear_user(void __user *addr, __kernel_size_t size)
{
        __kernel_size_t res;

#ifdef CONFIG_CPU_MICROMIPS
/* micromips memset / bzero also clobbers t7 & t8 */
#define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$15", "$24", "$31"
#else
#define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$31"
#endif /* CONFIG_CPU_MICROMIPS */

        might_fault();
        __asm__ __volatile__(
                "move\t$4, %1\n\t"
                "move\t$5, $0\n\t"
                "move\t$6, %2\n\t"
                __MODULE_JAL(__bzero)
                "move\t%0, $6"
                : "=r" (res)
                : "r" (addr), "r" (size)
                : bzero_clobbers);

        return res;
}

#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_asm(char *__to, const char __user *__from, long __len);

/*
 * strncpy_from_user: - Copy a NUL terminated string from userspace.
 * @dst:   Destination address, in kernel space.  This buffer must be at
 *         least @count bytes long.
 * @src:   Source address, in user space.
 * @count: Maximum number of bytes to copy, including the trailing NUL.
 *
 * Copies a NUL-terminated string from userspace to kernel space.
 *
 * On success, returns the length of the string (not including the trailing
 * NUL).
 *
 * If access to userspace fails, returns -EFAULT (some data may have been
 * copied).
 *
 * If @count is smaller than the length of the string, copies @count bytes
 * and returns @count.
 */
static inline long
strncpy_from_user(char *__to, const char __user *__from, long __len)
{
        long res;

        if (!access_ok(__from, __len))
                return -EFAULT;

        might_fault();
        __asm__ __volatile__(
                "move\t$4, %1\n\t"
                "move\t$5, %2\n\t"
                "move\t$6, %3\n\t"
                __MODULE_JAL(__strncpy_from_user_asm)
                "move\t%0, $2"
                : "=r" (res)
                : "r" (__to), "r" (__from), "r" (__len)
                : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");

        return res;
}

extern long __strnlen_user_asm(const char __user *s, long n);

/*
 * strnlen_user: - Get the size of a string in user space.
 * @str: The string to measure.
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * Get the size of a NUL-terminated string in user space.
 *
 * Returns the size of the string INCLUDING the terminating NUL.
 * On exception, returns 0.
 * If the string is too long, returns a value greater than @n.
 */
static inline long strnlen_user(const char __user *s, long n)
{
        long res;

        if (!access_ok(s, 1))
                return 0;

        might_fault();
        __asm__ __volatile__(
                "move\t$4, %1\n\t"
                "move\t$5, %2\n\t"
                __MODULE_JAL(__strnlen_user_asm)
                "move\t%0, $2"
                : "=r" (res)
                : "r" (s), "r" (n)
                : "$2", "$4", "$5", __UA_t0, "$31");

        return res;
}

#endif /* _ASM_UACCESS_H */