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uaccess.h

/*
 * Copyright 2004-2009 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 *
 * Based on: include/asm-m68knommu/uaccess.h
 */

#ifndef __BLACKFIN_UACCESS_H
#define __BLACKFIN_UACCESS_H

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

#include <asm/segment.h>
#include <asm/sections.h>

#define get_ds()        (KERNEL_DS)
#define get_fs()        (current_thread_info()->addr_limit)

static inline void set_fs(mm_segment_t fs)
{
      current_thread_info()->addr_limit = fs;
}

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

#define VERIFY_READ     0
#define VERIFY_WRITE    1

#define access_ok(type, addr, size) _access_ok((unsigned long)(addr), (size))

static inline int is_in_rom(unsigned long addr)
{
      /*
       * What we are really trying to do is determine if addr is
       * in an allocated kernel memory region. If not then assume
       * we cannot free it or otherwise de-allocate it. Ideally
       * we could restrict this to really being in a ROM or flash,
       * but that would need to be done on a board by board basis,
       * not globally.
       */
      if ((addr < _ramstart) || (addr >= _ramend))
            return (1);

      /* Default case, not in ROM */
      return (0);
}

/*
 * 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.
 */

#ifndef CONFIG_ACCESS_CHECK
static inline int _access_ok(unsigned long addr, unsigned long size) { return 1; }
#else
extern int _access_ok(unsigned long addr, unsigned long size);
#endif

/*
 * 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;
};

/*
 * 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,p)                                 \
      ({                                        \
            int _err = 0;                             \
            typeof(*(p)) _x = (x);                    \
            typeof(*(p)) *_p = (p);                   \
            if (!access_ok(VERIFY_WRITE, _p, sizeof(*(_p)))) {\
                  _err = -EFAULT;                     \
            }                                   \
            else {                                    \
            switch (sizeof (*(_p))) {                 \
            case 1:                                   \
                  __put_user_asm(_x, _p, B);          \
                  break;                              \
            case 2:                                   \
                  __put_user_asm(_x, _p, W);          \
                  break;                              \
            case 4:                                   \
                  __put_user_asm(_x, _p,  );          \
                  break;                              \
            case 8: {                           \
                  long _xl, _xh;                      \
                  _xl = ((long *)&_x)[0];             \
                  _xh = ((long *)&_x)[1];             \
                  __put_user_asm(_xl, ((long *)_p)+0, );    \
                  __put_user_asm(_xh, ((long *)_p)+1, );    \
            } break;                            \
            default:                            \
                  _err = __put_user_bad();            \
                  break;                              \
            }                                   \
            }                                   \
            _err;                               \
      })

#define __put_user(x,p) put_user(x,p)
static inline int bad_user_access_length(void)
{
      panic("bad_user_access_length");
      return -1;
}

#define __put_user_bad() (printk(KERN_INFO "put_user_bad %s:%d %s\n",\
                           __FILE__, __LINE__, __func__),\
                           bad_user_access_length(), (-EFAULT))

/*
 * Tell gcc we read from memory instead of writing: this is because
 * we do not write to any memory gcc knows about, so there are no
 * aliasing issues.
 */

#define __ptr(x) ((unsigned long *)(x))

#define __put_user_asm(x,p,bhw)                       \
      __asm__ (#bhw"[%1] = %0;\n\t"             \
             : /* no outputs */                 \
             :"d" (x),"a" (__ptr(p)) : "memory")

#define get_user(x, ptr)                              \
({                                              \
      int _err = 0;                                   \
      unsigned long _val = 0;                         \
      const typeof(*(ptr)) __user *_p = (ptr);        \
      const size_t ptr_size = sizeof(*(_p));                \
      if (likely(access_ok(VERIFY_READ, _p, ptr_size))) {   \
            BUILD_BUG_ON(ptr_size >= 8);              \
            switch (ptr_size) {                       \
            case 1:                                   \
                  __get_user_asm(_val, _p, B,(Z));    \
                  break;                              \
            case 2:                                   \
                  __get_user_asm(_val, _p, W,(Z));    \
                  break;                              \
            case 4:                                   \
                  __get_user_asm(_val, _p,  , );            \
                  break;                              \
            }                                   \
      } else                                          \
            _err = -EFAULT;                           \
      x = (typeof(*(ptr)))_val;                       \
      _err;                                     \
})

#define __get_user(x,p) get_user(x,p)

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

#define __get_user_asm(x, ptr, bhw, option)     \
({                                  \
      __asm__ __volatile__ (              \
            "%0 =" #bhw "[%1]" #option ";"      \
            : "=d" (x)              \
            : "a" (__ptr(ptr)));          \
})

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

#define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n))\
                                         return retval; })

#define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n))\
                                                   return retval; })

static inline unsigned long __must_check
copy_from_user(void *to, const void __user *from, unsigned long n)
{
      if (access_ok(VERIFY_READ, from, n))
            memcpy(to, from, n);
      else
            return n;
      return 0;
}

static inline unsigned long __must_check
copy_to_user(void *to, const void __user *from, unsigned long n)
{
      if (access_ok(VERIFY_WRITE, to, n))
            memcpy(to, from, n);
      else
            return n;
      return 0;
}

/*
 * Copy a null terminated string from userspace.
 */

static inline long __must_check
strncpy_from_user(char *dst, const char *src, long count)
{
      char *tmp;
      if (!access_ok(VERIFY_READ, src, 1))
            return -EFAULT;
      strncpy(dst, src, count);
      for (tmp = dst; *tmp && count > 0; tmp++, count--) ;
      return (tmp - dst);
}

/*
 * Get the size of a string in user space.
 *   src: The string to measure
 *     n: The maximum valid length
 *
 * 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 __must_check strnlen_user(const char *src, long n)
{
      if (!access_ok(VERIFY_READ, src, 1))
            return 0;
      return strnlen(src, n) + 1;
}

static inline long __must_check strlen_user(const char *src)
{
      if (!access_ok(VERIFY_READ, src, 1))
            return 0;
      return strlen(src) + 1;
}

/*
 * Zero Userspace
 */

static inline unsigned long __must_check
__clear_user(void *to, unsigned long n)
{
      if (!access_ok(VERIFY_WRITE, to, n))
            return n;
      memset(to, 0, n);
      return 0;
}

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

/* How to interpret these return values:
 *    CORE:      can be accessed by core load or dma memcpy
 *    CORE_ONLY: can only be accessed by core load
 *    DMA:       can only be accessed by dma memcpy
 *    IDMA:      can only be accessed by interprocessor dma memcpy (BF561)
 *    ITEST:     can be accessed by isram memcpy or dma memcpy
 */
enum {
      BFIN_MEM_ACCESS_CORE = 0,
      BFIN_MEM_ACCESS_CORE_ONLY,
      BFIN_MEM_ACCESS_DMA,
      BFIN_MEM_ACCESS_IDMA,
      BFIN_MEM_ACCESS_ITEST,
};
/**
 *    bfin_mem_access_type() - what kind of memory access is required
 *    @addr:   the address to check
 *    @size:   number of bytes needed
 *    @return: <0 is error, >=0 is BFIN_MEM_ACCESS_xxx enum (see above)
 */
int bfin_mem_access_type(unsigned long addr, unsigned long size);

#endif                        /* _BLACKFIN_UACCESS_H */

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