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 #ifdef CONFIG_ACCESS_OK_L1
  63 extern int _access_ok(unsigned long addr, unsigned long size)__attribute__((l1_text));
  64 #else
  65 extern int _access_ok(unsigned long addr, unsigned long size);
  66 #endif
  67 #endif
  68
  69 /*
  70  * The exception table consists of pairs of addresses: the first is the
  71  * address of an instruction that is allowed to fault, and the second is
  72  * the address at which the program should continue.  No registers are
  73  * modified, so it is entirely up to the continuation code to figure out
  74  * what to do.
  75  *
  76  * All the routines below use bits of fixup code that are out of line
  77  * with the main instruction path.  This means when everything is well,
  78  * we don't even have to jump over them.  Further, they do not intrude
  79  * on our cache or tlb entries.
  80  */
  81
  82 struct exception_table_entry {
  83         unsigned long insn, fixup;
  84 };
  85
  86 /*
  87  * These are the main single-value transfer routines.  They automatically
  88  * use the right size if we just have the right pointer type.
  89  */
  90
  91 #define put_user(x,p)                                           \
  92         ({                                                      \
  93                 int _err = 0;                                   \
  94                 typeof(*(p)) _x = (x);                          \
  95                 typeof(*(p)) *_p = (p);                         \
  96                 if (!access_ok(VERIFY_WRITE, _p, sizeof(*(_p)))) {\
  97                         _err = -EFAULT;                         \
  98                 }                                               \
  99                 else {                                          \
 100                 switch (sizeof (*(_p))) {                       \
 101                 case 1:                                         \
 102                         __put_user_asm(_x, _p, B);              \
 103                         break;                                  \
 104                 case 2:                                         \
 105                         __put_user_asm(_x, _p, W);              \
 106                         break;                                  \
 107                 case 4:                                         \
 108                         __put_user_asm(_x, _p,  );              \
 109                         break;                                  \
 110                 case 8: {                                       \
 111                         long _xl, _xh;                          \
 112                         _xl = ((long *)&_x)[0];                 \
 113                         _xh = ((long *)&_x)[1];                 \
 114                         __put_user_asm(_xl, ((long *)_p)+0, );  \
 115                         __put_user_asm(_xh, ((long *)_p)+1, );  \
 116                 } break;                                        \
 117                 default:                                        \
 118                         _err = __put_user_bad();                \
 119                         break;                                  \
 120                 }                                               \
 121                 }                                               \
 122                 _err;                                           \
 123         })
 124
 125 #define __put_user(x,p) put_user(x,p)
 126 static inline int bad_user_access_length(void)
 127 {
 128         panic("bad_user_access_length");
 129         return -1;
 130 }
 131
 132 #define __put_user_bad() (printk(KERN_INFO "put_user_bad %s:%d %s\n",\
 133                            __FILE__, __LINE__, __func__),\
 134                            bad_user_access_length(), (-EFAULT))
 135
 136 /*
 137  * Tell gcc we read from memory instead of writing: this is because
 138  * we do not write to any memory gcc knows about, so there are no
 139  * aliasing issues.
 140  */
 141
 142 #define __ptr(x) ((unsigned long *)(x))
 143
 144 #define __put_user_asm(x,p,bhw)                         \
 145         __asm__ (#bhw"[%1] = %0;\n\t"                   \
 146                  : /* no outputs */                     \
 147                  :"d" (x),"a" (__ptr(p)) : "memory")
 148
 149 #define get_user(x, ptr)                                        \
 150 ({                                                              \
 151         int _err = 0;                                           \
 152         unsigned long _val = 0;                                 \
 153         const typeof(*(ptr)) __user *_p = (ptr);                \
 154         const size_t ptr_size = sizeof(*(_p));                  \
 155         if (likely(access_ok(VERIFY_READ, _p, ptr_size))) {     \
 156                 BUILD_BUG_ON(ptr_size >= 8);                    \
 157                 switch (ptr_size) {                             \
 158                 case 1:                                         \
 159                         __get_user_asm(_val, _p, B,(Z));        \
 160                         break;                                  \
 161                 case 2:                                         \
 162                         __get_user_asm(_val, _p, W,(Z));        \
 163                         break;                                  \
 164                 case 4:                                         \
 165                         __get_user_asm(_val, _p,  , );          \
 166                         break;                                  \
 167                 }                                               \
 168         } else                                                  \
 169                 _err = -EFAULT;                                 \
 170         x = (typeof(*(ptr)))_val;                               \
 171         _err;                                                   \
 172 })
 173
 174 #define __get_user(x,p) get_user(x,p)
 175
 176 #define __get_user_bad() (bad_user_access_length(), (-EFAULT))
 177
 178 #define __get_user_asm(x, ptr, bhw, option)     \
 179 ({                                              \
 180         __asm__ __volatile__ (                  \
 181                 "%0 =" #bhw "[%1]" #option ";"  \
 182                 : "=d" (x)                      \
 183                 : "a" (__ptr(ptr)));            \
 184 })
 185
 186 #define __copy_from_user(to, from, n) copy_from_user(to, from, n)
 187 #define __copy_to_user(to, from, n) copy_to_user(to, from, n)
 188 #define __copy_to_user_inatomic __copy_to_user
 189 #define __copy_from_user_inatomic __copy_from_user
 190
 191 #define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n))\
 192                                                  return retval; })
 193
 194 #define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n))\
 195                                                    return retval; })
 196
 197 static inline unsigned long __must_check
 198 copy_from_user(void *to, const void __user *from, unsigned long n)
 199 {
 200         if (access_ok(VERIFY_READ, from, n))
 201                 memcpy(to, from, n);
 202         else
 203                 return n;
 204         return 0;
 205 }
 206
 207 static inline unsigned long __must_check
 208 copy_to_user(void *to, const void __user *from, unsigned long n)
 209 {
 210         if (access_ok(VERIFY_WRITE, to, n))
 211                 memcpy(to, from, n);
 212         else
 213                 return n;
 214         return 0;
 215 }
 216
 217 /*
 218  * Copy a null terminated string from userspace.
 219  */
 220
 221 static inline long __must_check
 222 strncpy_from_user(char *dst, const char *src, long count)
 223 {
 224         char *tmp;
 225         if (!access_ok(VERIFY_READ, src, 1))
 226                 return -EFAULT;
 227         strncpy(dst, src, count);
 228         for (tmp = dst; *tmp && count > 0; tmp++, count--) ;
 229         return (tmp - dst);
 230 }
 231
 232 /*
 233  * Get the size of a string in user space.
 234  *   src: The string to measure
 235  *     n: The maximum valid length
 236  *
 237  * Get the size of a NUL-terminated string in user space.
 238  *
 239  * Returns the size of the string INCLUDING the terminating NUL.
 240  * On exception, returns 0.
 241  * If the string is too long, returns a value greater than n.
 242  */
 243 static inline long __must_check strnlen_user(const char *src, long n)
 244 {
 245         if (!access_ok(VERIFY_READ, src, 1))
 246                 return 0;
 247         return strnlen(src, n) + 1;
 248 }
 249
 250 static inline long __must_check strlen_user(const char *src)
 251 {
 252         if (!access_ok(VERIFY_READ, src, 1))
 253                 return 0;
 254         return strlen(src) + 1;
 255 }
 256
 257 /*
 258  * Zero Userspace
 259  */
 260
 261 static inline unsigned long __must_check
 262 __clear_user(void *to, unsigned long n)
 263 {
 264         if (!access_ok(VERIFY_WRITE, to, n))
 265                 return n;
 266         memset(to, 0, n);
 267         return 0;
 268 }
 269
 270 #define clear_user(to, n) __clear_user(to, n)
 271
 272 #endif                          /* _BLACKFIN_UACCESS_H */