/*
 * User space memory access functions for Nios II
 *
 * Copyright (C) 2010-2011, Tobias Klauser <tklauser@distanz.ch>
 * Copyright (C) 2009, Wind River Systems Inc
 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
 *
 * 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.
 */

#ifndef _ASM_NIOS2_UACCESS_H
#define _ASM_NIOS2_UACCESS_H

#include <linux/string.h>

#include <asm/page.h>

#include <asm/extable.h>
#include <asm-generic/access_ok.h>

# define __EX_TABLE_SECTION     ".section __ex_table,\"a\"\n"

/*
 * Zero Userspace
 */

static inline unsigned long __must_check __clear_user(void __user *to,
                                                      unsigned long n)
{
        __asm__ __volatile__ (
                "1:     stb     zero, 0(%1)\n"
                "       addi    %0, %0, -1\n"
                "       addi    %1, %1, 1\n"
                "       bne     %0, zero, 1b\n"
                "2:\n"
                __EX_TABLE_SECTION
                ".word  1b, 2b\n"
                ".previous\n"
                : "=r" (n), "=r" (to)
                : "0" (n), "1" (to)
        );

        return n;
}

static inline unsigned long __must_check clear_user(void __user *to,
                                                    unsigned long n)
{
        if (!access_ok(to, n))
                return n;
        return __clear_user(to, n);
}

extern unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long n);
#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER

extern long strncpy_from_user(char *__to, const char __user *__from,
                              long __len);
extern __must_check long strnlen_user(const char __user *s, long n);

/* Optimized macros */
#define __get_user_asm(val, insn, addr, err)                            \
{                                                                       \
        unsigned long __gu_val;                                         \
        __asm__ __volatile__(                                           \
        "       movi    %0, %3\n"                                       \
        "1:   " insn " %1, 0(%2)\n"                                     \
        "       movi     %0, 0\n"                                       \
        "2:\n"                                                          \
        "       .section __ex_table,\"a\"\n"                            \
        "       .word 1b, 2b\n"                                         \
        "       .previous"                                              \
        : "=&r" (err), "=r" (__gu_val)                                  \
        : "r" (addr), "i" (-EFAULT));                                   \
        val = (__force __typeof__(*(addr)))__gu_val;                    \
}

extern void __get_user_unknown(void);

#define __get_user_8(val, ptr, err) do {                                \
        u64 __val = 0;                                                  \
        err = 0;                                                        \
        if (raw_copy_from_user(&(__val), ptr, sizeof(val))) {           \
                err = -EFAULT;                                          \
        } else {                                                        \
                val = (typeof(val))(typeof((val) - (val)))__val;        \
        }                                                               \
        } while (0)

#define __get_user_common(val, size, ptr, err)                          \
do {                                                                    \
        switch (size) {                                                 \
        case 1:                                                         \
                __get_user_asm(val, "ldbu", ptr, err);                  \
                break;                                                  \
        case 2:                                                         \
                __get_user_asm(val, "ldhu", ptr, err);                  \
                break;                                                  \
        case 4:                                                         \
                __get_user_asm(val, "ldw", ptr, err);                   \
                break;                                                  \
        case 8:                                                         \
                __get_user_8(val, ptr, err);                            \
                break;                                                  \
        default:                                                        \
                __get_user_unknown();                                   \
                break;                                                  \
        }                                                               \
} while (0)

#define __get_user(x, ptr)                                              \
        ({                                                              \
        long __gu_err = -EFAULT;                                        \
        const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);              \
        __get_user_common(x, sizeof(*(ptr)), __gu_ptr, __gu_err);       \
        __gu_err;                                                       \
        })

#define get_user(x, ptr)                                                \
({                                                                      \
        long __gu_err = -EFAULT;                                        \
        const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);              \
        if (access_ok( __gu_ptr, sizeof(*__gu_ptr)))    \
                __get_user_common(x, sizeof(*__gu_ptr),                 \
                        __gu_ptr, __gu_err);                            \
        __gu_err;                                                       \
})

#define __put_user_asm(val, insn, ptr, err)                             \
{                                                                       \
        __asm__ __volatile__(                                           \
        "       movi    %0, %3\n"                                       \
        "1:   " insn " %1, 0(%2)\n"                                     \
        "       movi     %0, 0\n"                                       \
        "2:\n"                                                          \
        "       .section __ex_table,\"a\"\n"                            \
        "       .word 1b, 2b\n"                                         \
        "       .previous\n"                                            \
        : "=&r" (err)                                                   \
        : "r" (val), "r" (ptr), "i" (-EFAULT));                         \
}

#define __put_user_common(__pu_val, __pu_ptr)                           \
({                                                                      \
        long __pu_err = -EFAULT;                                        \
        switch (sizeof(*__pu_ptr)) {                                    \
        case 1:                                                         \
                __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err);    \
                break;                                                  \
        case 2:                                                         \
                __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err);    \
                break;                                                  \
        case 4:                                                         \
                __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err);    \
                break;                                                  \
        default:                                                        \
                /* XXX: This looks wrong... */                          \
                __pu_err = 0;                                           \
                if (__copy_to_user(__pu_ptr, &(__pu_val),               \
                        sizeof(*__pu_ptr)))                             \
                        __pu_err = -EFAULT;                             \
                break;                                                  \
        }                                                               \
        __pu_err;                                                       \
})

#define __put_user(x, ptr)                                              \
({                                                                      \
        auto __pu_ptr = (ptr);                                          \
        auto __pu_val = (typeof(*__pu_ptr))(x);                         \
        __put_user_common(__pu_val, __pu_ptr);                          \
})

#define put_user(x, ptr)                                                \
({                                                                      \
        auto __pu_ptr = (ptr);                                          \
        auto __pu_val = (typeof(*__pu_ptr))(x);                         \
        access_ok(__pu_ptr, sizeof(*__pu_ptr)) ?                        \
                __put_user_common(__pu_val, __pu_ptr) :                 \
                -EFAULT;                                                \
})

#endif /* _ASM_NIOS2_UACCESS_H */