#ifndef __METAG_UACCESS_H
#define __METAG_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/sched.h>

#define VERIFY_READ     0
#define VERIFY_WRITE    1

/*
 * The fs value determines whether argument validity checking should be
 * performed or not.  If get_fs() == USER_DS, checking is performed, with
 * get_fs() == KERNEL_DS, checking is bypassed.
 *
 * For historical reasons, these macros are grossly misnamed.
 */

#define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })

#define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
#define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)

#define get_ds()        (KERNEL_DS)
#define get_fs()        (current_thread_info()->addr_limit)
#define set_fs(x)       (current_thread_info()->addr_limit = (x))

#define segment_eq(a, b)        ((a).seg == (b).seg)

#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
/*
 * Explicitly allow NULL pointers here. Parts of the kernel such
 * as readv/writev use access_ok to validate pointers, but want
 * to allow NULL pointers for various reasons. NULL pointers are
 * safe to allow through because the first page is not mappable on
 * Meta.
 *
 * We also wish to avoid letting user code access the system area
 * and the kernel half of the address space.
 */
#define __user_bad(addr, size) (((addr) > 0 && (addr) < META_MEMORY_BASE) || \
                                ((addr) > PAGE_OFFSET &&                \
                                 (addr) < LINCORE_BASE))

static inline int __access_ok(unsigned long addr, unsigned long size)
{
        return __kernel_ok || !__user_bad(addr, size);
}

#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),  \
                                                (unsigned long)(size))

static inline int verify_area(int type, const void *addr, unsigned long size)
{
        return access_ok(type, addr, size) ? 0 : -EFAULT;
}

/*
 * The exception table consists of pairs of addresses: the first is the
 * address of an instruction that is allowed to fault, and the second is
 * the address at which the program should continue.  No registers are
 * modified, so it is entirely up to the continuation code to figure out
 * what to do.
 *
 * All the routines below use bits of fixup code that are out of line
 * with the main instruction path.  This means when everything is well,
 * we don't even have to jump over them.  Further, they do not intrude
 * on our cache or tlb entries.
 */
struct exception_table_entry {
        unsigned long insn, fixup;
};

extern int fixup_exception(struct pt_regs *regs);

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 */

#define put_user(x, ptr) \
        __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
#define __put_user(x, ptr) \
        __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

extern void __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(VERIFY_WRITE, __pu_addr, size))           \
                __put_user_size((x), __pu_addr, (size), __pu_err);      \
        __pu_err;                                               \
})

extern long __put_user_asm_b(unsigned int x, void __user *addr);
extern long __put_user_asm_w(unsigned int x, void __user *addr);
extern long __put_user_asm_d(unsigned int x, void __user *addr);
extern long __put_user_asm_l(unsigned long long x, void __user *addr);

#define __put_user_size(x, ptr, size, retval)                   \
do {                                                            \
        retval = 0;                                             \
        switch (size) {                                         \
        case 1:                                                         \
                retval = __put_user_asm_b((unsigned int)x, ptr); break; \
        case 2:                                                         \
                retval = __put_user_asm_w((unsigned int)x, ptr); break; \
        case 4:                                                         \
                retval = __put_user_asm_d((unsigned int)x, ptr); break; \
        case 8:                                                         \
                retval = __put_user_asm_l((unsigned long long)x, ptr); break; \
        default:                                                        \
                __put_user_bad();                                       \
        }                                                               \
} while (0)

#define get_user(x, ptr) \
        __get_user_check((x), (ptr), sizeof(*(ptr)))
#define __get_user(x, ptr) \
        __get_user_nocheck((x), (ptr), sizeof(*(ptr)))

extern long __get_user_bad(void);

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

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

extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
extern unsigned int __get_user_asm_d(const void __user *addr, long *err);

#define __get_user_size(x, ptr, size, retval)                   \
do {                                                            \
        retval = 0;                                             \
        switch (size) {                                         \
        case 1:                                                 \
                x = __get_user_asm_b(ptr, &retval); break;      \
        case 2:                                                 \
                x = __get_user_asm_w(ptr, &retval); break;      \
        case 4:                                                 \
                x = __get_user_asm_d(ptr, &retval); break;      \
        default:                                                \
                (x) = __get_user_bad();                         \
        }                                                       \
} while (0)

/*
 * Copy a null terminated string from userspace.
 *
 * Must return:
 * -EFAULT              for an exception
 * count                if we hit the buffer limit
 * bytes copied         if we hit a null byte
 * (without the null byte)
 */

extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
                                             long count);

#define strncpy_from_user(dst, src, count) __strncpy_from_user(dst, src, count)

/*
 * Return the size of a string (including the ending 0)
 *
 * Return 0 on exception, a value greater than N if too long
 */
extern long __must_check strnlen_user(const char __user *src, long count);

#define strlen_user(str) strnlen_user(str, 32767)

extern unsigned long __must_check __copy_user_zeroing(void *to,
                                                      const void __user *from,
                                                      unsigned long n);

static inline unsigned long
copy_from_user(void *to, const void __user *from, unsigned long n)
{
        if (access_ok(VERIFY_READ, from, n))
                return __copy_user_zeroing(to, from, n);
        return n;
}

#define __copy_from_user(to, from, n) __copy_user_zeroing(to, from, n)
#define __copy_from_user_inatomic __copy_from_user

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

static inline unsigned long copy_to_user(void __user *to, const void *from,
                                         unsigned long n)
{
        if (access_ok(VERIFY_WRITE, to, n))
                return __copy_user(to, from, n);
        return n;
}

#define __copy_to_user(to, from, n) __copy_user(to, from, n)
#define __copy_to_user_inatomic __copy_to_user

/*
 * Zero Userspace
 */

extern unsigned long __must_check __do_clear_user(void __user *to,
                                                  unsigned long n);

static inline unsigned long clear_user(void __user *to, unsigned long n)
{
        if (access_ok(VERIFY_WRITE, to, n))
                return __do_clear_user(to, n);
        return n;
}

#define __clear_user(to, n)            __do_clear_user(to, n)

#endif /* _METAG_UACCESS_H */