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uaccess.h

/*
 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2008-2009 PetaLogix
 * Copyright (C) 2006 Atmark Techno, Inc.
 *
 * 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_MICROBLAZE_UACCESS_H
#define _ASM_MICROBLAZE_UACCESS_H

#ifdef __KERNEL__
#ifndef __ASSEMBLY__

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/sched.h> /* RLIMIT_FSIZE */
#include <linux/mm.h>

#include <asm/mmu.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/segment.h>
#include <linux/string.h>

#define VERIFY_READ     0
#define VERIFY_WRITE    1

#define __clear_user(addr, n) (memset((void *)(addr), 0, (n)), 0)

#ifndef CONFIG_MMU

extern int ___range_ok(unsigned long addr, unsigned long size);

#define __range_ok(addr, size) \
            ___range_ok((unsigned long)(addr), (unsigned long)(size))

#define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
#define __access_ok(add, size) (__range_ok((addr), (size)) == 0)

/* Undefined function to trigger linker error */
extern int bad_user_access_length(void);

/* FIXME this is function for optimalization -> memcpy */
#define __get_user(var, ptr)                    \
({                                        \
      int __gu_err = 0;                   \
      switch (sizeof(*(ptr))) {                 \
      case 1:                                   \
      case 2:                                   \
      case 4:                                   \
            (var) = *(ptr);                     \
            break;                              \
      case 8:                                   \
            memcpy((void *) &(var), (ptr), 8);  \
            break;                              \
      default:                            \
            (var) = 0;                    \
            __gu_err = __get_user_bad();        \
            break;                              \
      }                                   \
      __gu_err;                           \
})

#define __get_user_bad()      (bad_user_access_length(), (-EFAULT))

/* FIXME is not there defined __pu_val */
#define __put_user(var, ptr)                          \
({                                              \
      int __pu_err = 0;                         \
      switch (sizeof(*(ptr))) {                       \
      case 1:                                         \
      case 2:                                         \
      case 4:                                         \
            *(ptr) = (var);                           \
            break;                                    \
      case 8: {                                 \
            typeof(*(ptr)) __pu_val = (var);          \
            memcpy(ptr, &__pu_val, sizeof(__pu_val)); \
            }                                   \
            break;                                    \
      default:                                  \
            __pu_err = __put_user_bad();              \
            break;                                    \
      }                                         \
      __pu_err;                                 \
})

#define __put_user_bad()      (bad_user_access_length(), (-EFAULT))

#define put_user(x, ptr)      __put_user((x), (ptr))
#define get_user(x, ptr)      __get_user((x), (ptr))

#define copy_to_user(to, from, n)   (memcpy((to), (from), (n)), 0)
#define copy_from_user(to, from, n) (memcpy((to), (from), (n)), 0)

#define __copy_to_user(to, from, n) (copy_to_user((to), (from), (n)))
#define __copy_from_user(to, from, n)     (copy_from_user((to), (from), (n)))
#define __copy_to_user_inatomic(to, from, n) \
                  (__copy_to_user((to), (from), (n)))
#define __copy_from_user_inatomic(to, from, n) \
                  (__copy_from_user((to), (from), (n)))

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

/* Returns 0 if exception not found and fixup otherwise.  */
extern unsigned long search_exception_table(unsigned long);

extern long strncpy_from_user(char *dst, const char *src, long count);
extern long strnlen_user(const char *src, long count);

#else /* CONFIG_MMU */

/*
 * Address is valid if:
 *  - "addr", "addr + size" and "size" are all below the limit
 */
#define access_ok(type, addr, size) \
      (get_fs().seg > (((unsigned long)(addr)) | \
            (size) | ((unsigned long)(addr) + (size))))

/* || printk("access_ok failed for %s at 0x%08lx (size %d), seg 0x%08x\n",
 type?"WRITE":"READ",addr,size,get_fs().seg)) */

/*
 * All the __XXX versions macros/functions below do not perform
 * access checking. It is assumed that the necessary checks have been
 * already performed before the finction (macro) is called.
 */

#define get_user(x, ptr)                                    \
({                                                    \
      access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))               \
            ? __get_user((x), (ptr)) : -EFAULT;             \
})

#define put_user(x, ptr)                                    \
({                                                    \
      access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr)))              \
            ? __put_user((x), (ptr)) : -EFAULT;             \
})

#define __get_user(x, ptr)                                  \
({                                                    \
      unsigned long __gu_val;                               \
      /*unsigned long __gu_ptr = (unsigned long)(ptr);*/          \
      long __gu_err;                                        \
      switch (sizeof(*(ptr))) {                             \
      case 1:                                               \
            __get_user_asm("lbu", (ptr), __gu_val, __gu_err);     \
            break;                                          \
      case 2:                                               \
            __get_user_asm("lhu", (ptr), __gu_val, __gu_err);     \
            break;                                          \
      case 4:                                               \
            __get_user_asm("lw", (ptr), __gu_val, __gu_err);      \
            break;                                          \
      default:                                        \
            __gu_val = 0; __gu_err = -EINVAL;               \
      }                                               \
      x = (__typeof__(*(ptr))) __gu_val;                    \
      __gu_err;                                       \
})

#define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)        \
({                                                    \
      __asm__ __volatile__ (                                \
                  "1:"  insn  " %1, %2, r0;                 \
                        addk  %0, r0, r0;             \
                  2:                                  \
                  .section .fixup,\"ax\";                   \
                  3:    brid  2b;                     \
                        addik %0, r0, %3;             \
                  .previous;                          \
                  .section __ex_table,\"a\";                \
                  .word 1b,3b;                              \
                  .previous;"                         \
            : "=r"(__gu_err), "=r"(__gu_val)                \
            : "r"(__gu_ptr), "i"(-EFAULT)                   \
      );                                              \
})

#define __put_user(x, ptr)                                  \
({                                                    \
      __typeof__(*(ptr)) volatile __gu_val = (x);                 \
      long __gu_err = 0;                                    \
      switch (sizeof(__gu_val)) {                           \
      case 1:                                               \
            __put_user_asm("sb", (ptr), __gu_val, __gu_err);      \
            break;                                          \
      case 2:                                         \
            __put_user_asm("sh", (ptr), __gu_val, __gu_err);      \
            break;                                          \
      case 4:                                               \
            __put_user_asm("sw", (ptr), __gu_val, __gu_err);      \
            break;                                          \
      case 8:                                               \
            __put_user_asm_8((ptr), __gu_val, __gu_err);          \
            break;                                          \
      default:                                        \
            __gu_err = -EINVAL;                             \
      }                                               \
      __gu_err;                                       \
})

#define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)      \
({                                        \
__asm__ __volatile__ (" lwi   %0, %1, 0;        \
            1:    swi   %0, %2, 0;        \
                  lwi   %0, %1, 4;        \
            2:    swi   %0, %2, 4;        \
                  addk  %0,r0,r0;         \
            3:                            \
            .section .fixup,\"ax\";             \
            4:    brid  3b;               \
                  addik %0, r0, %3;       \
            .previous;                    \
            .section __ex_table,\"a\";          \
            .word 1b,4b,2b,4b;                  \
            .previous;"                   \
      : "=&r"(__gu_err)                   \
      : "r"(&__gu_val),                   \
      "r"(__gu_ptr), "i"(-EFAULT)               \
      );                                  \
})

#define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)  \
({                                              \
      __asm__ __volatile__ (                          \
                  "1:"  insn  " %1, %2, r0;           \
                        addk  %0, r0, r0;       \
                  2:                            \
                  .section .fixup,\"ax\";             \
                  3:    brid  2b;               \
                        addik %0, r0, %3;       \
                  .previous;                    \
                  .section __ex_table,\"a\";          \
                  .word 1b,3b;                        \
                  .previous;"                   \
            : "=r"(__gu_err)                    \
            : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
      );                                        \
})

/*
 * Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail.
 */
static inline int clear_user(char *to, int size)
{
      if (size && access_ok(VERIFY_WRITE, to, size)) {
            __asm__ __volatile__ ("                   \
                        1:                      \
                              sb    r0, %2, r0; \
                              addik %0, %0, -1; \
                              bneid %0, 1b;           \
                              addik %2, %2, 1;  \
                        2:                      \
                        .section __ex_table,\"a\";    \
                        .word 1b,2b;                  \
                        .section .text;"        \
                  : "=r"(size)                        \
                  : "0"(size), "r"(to)
            );
      }
      return size;
}

extern unsigned long __copy_tofrom_user(void __user *to,
            const void __user *from, unsigned long size);

#define copy_to_user(to, from, n)                           \
      (access_ok(VERIFY_WRITE, (to), (n)) ?                       \
            __copy_tofrom_user((void __user *)(to),               \
                  (__force const void __user *)(from), (n)) \
            : -EFAULT)

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

#define copy_from_user(to, from, n)                         \
      (access_ok(VERIFY_READ, (from), (n)) ?                      \
            __copy_tofrom_user((__force void __user *)(to),       \
                  (void __user *)(from), (n))               \
            : -EFAULT)

#define __copy_from_user(to, from, n)     copy_from_user((to), (from), (n))
#define __copy_from_user_inatomic(to, from, n) \
            copy_from_user((to), (from), (n))

extern int __strncpy_user(char *to, const char __user *from, int len);
extern int __strnlen_user(const char __user *sstr, int len);

#define strncpy_from_user(to, from, len)  \
            (access_ok(VERIFY_READ, from, 1) ?  \
                  __strncpy_user(to, from, len) : -EFAULT)
#define strnlen_user(str, len)      \
            (access_ok(VERIFY_READ, str, 1) ? __strnlen_user(str, len) : 0)

#endif /* CONFIG_MMU */

/*
 * 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;
};

#endif  /* __ASSEMBLY__ */
#endif /* __KERNEL__ */

#endif /* _ASM_MICROBLAZE_UACCESS_H */

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