arch/blackfin/include/asm/uaccess.h

   1 /* Changes made by Lineo Inc.    May 2001
   2  *
   3  * Based on: include/asm-m68knommu/uaccess.h
   4  */
   5
   6 #ifndef __BLACKFIN_UACCESS_H
   7 #define __BLACKFIN_UACCESS_H
   8
   9 /*
  10  * User space memory access functions
  11  */
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14 #include <linux/string.h>
  15
  16 #include <asm/segment.h>
  17 #ifdef CONFIG_ACCESS_CHECK
  18 # include <asm/bfin-global.h>
  19 #endif
  20
  21 #define get_ds()        (KERNEL_DS)
  22 #define get_fs()        (current_thread_info()->addr_limit)
  23
  24 static inline void set_fs(mm_segment_t fs)
  25 {
  26         current_thread_info()->addr_limit = fs;
  27 }
  28
  29 #define segment_eq(a,b) ((a) == (b))
  30
  31 #define VERIFY_READ     0
  32 #define VERIFY_WRITE    1
  33
  34 #define access_ok(type, addr, size) _access_ok((unsigned long)(addr), (size))
  35
  36 static inline int is_in_rom(unsigned long addr)
  37 {
  38         /*
  39          * What we are really trying to do is determine if addr is
  40          * in an allocated kernel memory region. If not then assume
  41          * we cannot free it or otherwise de-allocate it. Ideally
  42          * we could restrict this to really being in a ROM or flash,
  43          * but that would need to be done on a board by board basis,
  44          * not globally.
  45          */
  46         if ((addr < _ramstart) || (addr >= _ramend))
  47                 return (1);
  48
  49         /* Default case, not in ROM */
  50         return (0);
  51 }
  52
  53 /*
  54  * The fs value determines whether argument validity checking should be
  55  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  56  * get_fs() == KERNEL_DS, checking is bypassed.
  57  */
  58
  59 #ifndef CONFIG_ACCESS_CHECK
  60 static inline int _access_ok(unsigned long addr, unsigned long size) { return 1; }
  61 #else
  62 extern int _access_ok(unsigned long addr, unsigned long size);
  63 #endif
  64
  65 /*
  66  * The exception table consists of pairs of addresses: the first is the
  67  * address of an instruction that is allowed to fault, and the second is
  68  * the address at which the program should continue.  No registers are
  69  * modified, so it is entirely up to the continuation code to figure out
  70  * what to do.
  71  *
  72  * All the routines below use bits of fixup code that are out of line
  73  * with the main instruction path.  This means when everything is well,
  74  * we don't even have to jump over them.  Further, they do not intrude
  75  * on our cache or tlb entries.
  76  */
  77
  78 struct exception_table_entry {
  79         unsigned long insn, fixup;
  80 };
  81
  82 /*
  83  * These are the main single-value transfer routines.  They automatically
  84  * use the right size if we just have the right pointer type.
  85  */
  86
  87 #define put_user(x,p)                                           \
  88         ({                                                      \
  89                 int _err = 0;                                   \
  90                 typeof(*(p)) _x = (x);                          \
  91                 typeof(*(p)) *_p = (p);                         \
  92                 if (!access_ok(VERIFY_WRITE, _p, sizeof(*(_p)))) {\
  93                         _err = -EFAULT;                         \
  94                 }                                               \
  95                 else {                                          \
  96                 switch (sizeof (*(_p))) {                       \
  97                 case 1:                                         \
  98                         __put_user_asm(_x, _p, B);              \
  99                         break;                                  \
 100                 case 2:                                         \
 101                         __put_user_asm(_x, _p, W);              \
 102                         break;                                  \
 103                 case 4:                                         \
 104                         __put_user_asm(_x, _p,  );              \
 105                         break;                                  \
 106                 case 8: {                                       \
 107                         long _xl, _xh;                          \
 108                         _xl = ((long *)&_x)[0];                 \
 109                         _xh = ((long *)&_x)[1];                 \
 110                         __put_user_asm(_xl, ((long *)_p)+0, );  \
 111                         __put_user_asm(_xh, ((long *)_p)+1, );  \
 112                 } break;                                        \
 113                 default:                                        \
 114                         _err = __put_user_bad();                \
 115                         break;                                  \
 116                 }                                               \
 117                 }                                               \
 118                 _err;                                           \
 119         })
 120
 121 #define __put_user(x,p) put_user(x,p)
 122 static inline int bad_user_access_length(void)
 123 {
 124         panic("bad_user_access_length");
 125         return -1;
 126 }
 127
 128 #define __put_user_bad() (printk(KERN_INFO "put_user_bad %s:%d %s\n",\
 129                            __FILE__, __LINE__, __func__),\
 130                            bad_user_access_length(), (-EFAULT))
 131
 132 /*
 133  * Tell gcc we read from memory instead of writing: this is because
 134  * we do not write to any memory gcc knows about, so there are no
 135  * aliasing issues.
 136  */
 137
 138 #define __ptr(x) ((unsigned long *)(x))
 139
 140 #define __put_user_asm(x,p,bhw)                         \
 141         __asm__ (#bhw"[%1] = %0;\n\t"                   \
 142                  : /* no outputs */                     \
 143                  :"d" (x),"a" (__ptr(p)) : "memory")
 144
 145 #define get_user(x, ptr)                                        \
 146 ({                                                              \
 147         int _err = 0;                                           \
 148         unsigned long _val = 0;                                 \
 149         const typeof(*(ptr)) __user *_p = (ptr);                \
 150         const size_t ptr_size = sizeof(*(_p));                  \
 151         if (likely(access_ok(VERIFY_READ, _p, ptr_size))) {     \
 152                 BUILD_BUG_ON(ptr_size >= 8);                    \
 153                 switch (ptr_size) {                             \
 154                 case 1:                                         \
 155                         __get_user_asm(_val, _p, B,(Z));        \
 156                         break;                                  \
 157                 case 2:                                         \
 158                         __get_user_asm(_val, _p, W,(Z));        \
 159                         break;                                  \
 160                 case 4:                                         \
 161                         __get_user_asm(_val, _p,  , );          \
 162                         break;                                  \
 163                 }                                               \
 164         } else                                                  \
 165                 _err = -EFAULT;                                 \
 166         x = (typeof(*(ptr)))_val;                               \
 167         _err;                                                   \
 168 })
 169
 170 #define __get_user(x,p) get_user(x,p)
 171
 172 #define __get_user_bad() (bad_user_access_length(), (-EFAULT))
 173
 174 #define __get_user_asm(x, ptr, bhw, option)     \
 175 ({                                              \
 176         __asm__ __volatile__ (                  \
 177                 "%0 =" #bhw "[%1]" #option ";"  \
 178                 : "=d" (x)                      \
 179                 : "a" (__ptr(ptr)));            \
 180 })
 181
 182 #define __copy_from_user(to, from, n) copy_from_user(to, from, n)
 183 #define __copy_to_user(to, from, n) copy_to_user(to, from, n)
 184 #define __copy_to_user_inatomic __copy_to_user
 185 #define __copy_from_user_inatomic __copy_from_user
 186
 187 #define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n))\
 188                                                  return retval; })
 189
 190 #define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n))\
 191                                                    return retval; })
 192
 193 static inline unsigned long __must_check
 194 copy_from_user(void *to, const void __user *from, unsigned long n)
 195 {
 196         if (access_ok(VERIFY_READ, from, n))
 197                 memcpy(to, from, n);
 198         else
 199                 return n;
 200         return 0;
 201 }
 202
 203 static inline unsigned long __must_check
 204 copy_to_user(void *to, const void __user *from, unsigned long n)
 205 {
 206         if (access_ok(VERIFY_WRITE, to, n))
 207                 memcpy(to, from, n);
 208         else
 209                 return n;
 210         return 0;
 211 }
 212
 213 /*
 214  * Copy a null terminated string from userspace.
 215  */
 216
 217 static inline long __must_check
 218 strncpy_from_user(char *dst, const char *src, long count)
 219 {
 220         char *tmp;
 221         if (!access_ok(VERIFY_READ, src, 1))
 222                 return -EFAULT;
 223         strncpy(dst, src, count);
 224         for (tmp = dst; *tmp && count > 0; tmp++, count--) ;
 225         return (tmp - dst);
 226 }
 227
 228 /*
 229  * Get the size of a string in user space.
 230  *   src: The string to measure
 231  *     n: The maximum valid length
 232  *
 233  * Get the size of a NUL-terminated string in user space.
 234  *
 235  * Returns the size of the string INCLUDING the terminating NUL.
 236  * On exception, returns 0.
 237  * If the string is too long, returns a value greater than n.
 238  */
 239 static inline long __must_check strnlen_user(const char *src, long n)
 240 {
 241         if (!access_ok(VERIFY_READ, src, 1))
 242                 return 0;
 243         return strnlen(src, n) + 1;
 244 }
 245
 246 static inline long __must_check strlen_user(const char *src)
 247 {
 248         if (!access_ok(VERIFY_READ, src, 1))
 249                 return 0;
 250         return strlen(src) + 1;
 251 }
 252
 253 /*
 254  * Zero Userspace
 255  */
 256
 257 static inline unsigned long __must_check
 258 __clear_user(void *to, unsigned long n)
 259 {
 260         if (!access_ok(VERIFY_WRITE, to, n))
 261                 return n;
 262         memset(to, 0, n);
 263         return 0;
 264 }
 265
 266 #define clear_user(to, n) __clear_user(to, n)
 267
 268 #endif                          /* _BLACKFIN_UACCESS_H */