include/asm-blackfin/uaccess.h

   1 /*
   2  * U-boot - uaccess.h
   3  *
   4  * Copyright (c) 2005-2007 Analog Devices Inc.
   5  *
   6  * This file is based on
   7  * Based on: include/asm-m68knommu/uaccess.h
   8  * Changes made by Lineo Inc.    May 2001
   9  *
  10  * See file CREDITS for list of people who contributed to this
  11  * project.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License as
  15  * published by the Free Software Foundation; either version 2 of
  16  * the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  26  * MA 02110-1301 USA
  27  */
  28
  29 #ifndef __BLACKFIN_UACCESS_H
  30 #define __BLACKFIN_UACCESS_H
  31
  32 /*
  33  * User space memory access functions
  34  */
  35 #include <asm/segment.h>
  36 #include <asm/errno.h>
  37
  38 #define VERIFY_READ     0
  39 #define VERIFY_WRITE    1
  40
  41 /* We let the MMU do all checking */
  42 static inline int access_ok(int type, const void *addr, unsigned long size)
  43 {
  44         return ((unsigned long)addr < 0x10f00000);      /* need final decision - Tony */
  45 }
  46
  47 static inline int verify_area(int type, const void *addr, unsigned long size)
  48 {
  49         return access_ok(type, addr, size) ? 0 : -EFAULT;
  50 }
  51
  52 /*
  53  * The exception table consists of pairs of addresses: the first is the
  54  * address of an instruction that is allowed to fault, and the second is
  55  * the address at which the program should continue.  No registers are
  56  * modified, so it is entirely up to the continuation code to figure out
  57  * what to do.
  58  *
  59  * All the routines below use bits of fixup code that are out of line
  60  * with the main instruction path.  This means when everything is well,
  61  * we don't even have to jump over them.  Further, they do not intrude
  62  * on our cache or tlb entries.
  63  */
  64
  65 struct exception_table_entry {
  66         unsigned long insn, fixup;
  67 };
  68
  69 /* Returns 0 if exception not found and fixup otherwise.  */
  70 extern unsigned long search_exception_table(unsigned long);
  71
  72 /*
  73  * These are the main single-value transfer routines.  They automatically
  74  * use the right size if we just have the right pointer type.
  75  */
  76
  77 #define put_user(x, ptr)                                \
  78 ({                                                      \
  79     int __pu_err = 0;                                   \
  80     typeof(*(ptr)) __pu_val = (x);                      \
  81     switch (sizeof (*(ptr))) {                          \
  82     case 1:                                             \
  83         __put_user_asm(__pu_err, __pu_val, ptr, B);     \
  84         break;                                          \
  85     case 2:                                             \
  86         __put_user_asm(__pu_err, __pu_val, ptr, W);     \
  87         break;                                          \
  88     case 4:                                             \
  89         __put_user_asm(__pu_err, __pu_val, ptr,  );     \
  90         break;                                          \
  91     default:                                            \
  92         __pu_err = __put_user_bad();                    \
  93         break;                                          \
  94     }                                                   \
  95     __pu_err;                                           \
  96 })
  97 /*
  98  * [pregs] = dregs  ==> 32bits
  99  * H[pregs] = dregs  ==> 16bits
 100  * B[pregs] = dregs  ==> 8 bits
 101  */
 102
 103 #define __put_user(x, ptr) put_user(x, ptr)
 104
 105 static inline int bad_user_access_length(void)
 106 {
 107         panic("bad_user_access_length");
 108         return -1;
 109 }
 110
 111 #define __put_user_bad() (bad_user_access_length(), (-EFAULT))
 112
 113 /*
 114  * Tell gcc we read from memory instead of writing: this is because
 115  * we do not write to any memory gcc knows about, so there are no
 116  * aliasing issues.
 117  */
 118
 119 #define __ptr(x) ((unsigned long *)(x))
 120
 121 #define __put_user_asm(err,x,ptr,bhw)                                   \
 122         __asm__ (#bhw"[%1] = %0;\n\t"                                   \
 123                 :       /* no outputs */                                \
 124                 :"d" (x),"a" (__ptr(ptr)) : "memory")
 125
 126 #define get_user(x, ptr)                                                \
 127 ({                                                                      \
 128         int __gu_err = 0;                                               \
 129         typeof(*(ptr)) __gu_val = 0;                                    \
 130         switch (sizeof(*(ptr))) {                                       \
 131         case 1:                                                         \
 132                 __get_user_asm(__gu_err, __gu_val, ptr, B, "=d",(Z));   \
 133                 break;                                                  \
 134         case 2:                                                         \
 135                 __get_user_asm(__gu_err, __gu_val, ptr, W, "=r",(Z));   \
 136                 break;                                                  \
 137         case 4:                                                         \
 138                 __get_user_asm(__gu_err, __gu_val, ptr,  , "=r",);      \
 139                 break;                                                  \
 140         default:                                                        \
 141                 __gu_val = 0;                                           \
 142                 __gu_err = __get_user_bad();                            \
 143                 break;                                                  \
 144         }                                                               \
 145         (x) = __gu_val;                                                 \
 146         __gu_err;                                                       \
 147 })
 148
 149 /* dregs = [pregs] ==> 32bits
 150  * H[pregs]   ==> 16bits
 151  * B[pregs]   ==> 8 bits
 152  */
 153
 154 #define __get_user(x, ptr)      get_user(x, ptr)
 155 #define __get_user_bad()        (bad_user_access_length(), (-EFAULT))
 156
 157 #define __get_user_asm(err,x,ptr,bhw,reg,option)                \
 158         __asm__ ("%0 =" #bhw "[%1]"#option";\n\t"               \
 159                 : "=d" (x)                                      \
 160                 : "a" (__ptr(ptr)))
 161
 162 #define copy_from_user(to, from, n)     (memcpy(to, from, n), 0)
 163 #define copy_to_user(to, from, n)       (memcpy(to, from, n), 0)
 164
 165 #define __copy_from_user(to, from, n)   copy_from_user(to, from, n)
 166 #define __copy_to_user(to, from, n)     copy_to_user(to, from, n)
 167
 168 #define copy_to_user_ret(to,from,n,retval)      ({ if (copy_to_user(to,from,n)) return retval; })
 169 #define copy_from_user_ret(to,from,n,retval)    ({ if (copy_from_user(to,from,n)) return retval; })
 170
 171 /*
 172  * Copy a null terminated string from userspace.
 173  */
 174
 175 static inline long strncpy_from_user(char *dst, const char *src, long count)
 176 {
 177         char *tmp;
 178         strncpy(dst, src, count);
 179         for (tmp = dst; *tmp && count > 0; tmp++, count--) ;
 180         return (tmp - dst);     /* DAVIDM should we count a NUL ?  check getname */
 181 }
 182
 183 /*
 184  * Return the size of a string (including the ending 0)
 185  *
 186  * Return 0 on exception, a value greater than N if too long
 187  */
 188 static inline long strnlen_user(const char *src, long n)
 189 {
 190         return (strlen(src) + 1);       /* DAVIDM make safer */
 191 }
 192
 193 #define strlen_user(str) strnlen_user(str, 32767)
 194
 195 /*
 196  * Zero Userspace
 197  */
 198
 199 static inline unsigned long clear_user(void *to, unsigned long n)
 200 {
 201         memset(to, 0, n);
 202         return (0);
 203 }
 204
 205 #endif