arch/blackfin/include/asm/uaccess.h

   1 /*
   2  * Copyright 2004-2009 Analog Devices Inc.
   3  *
   4  * Licensed under the GPL-2 or later.
   5  *
   6  * Based on: include/asm-m68knommu/uaccess.h
   7  */
   8
   9 #ifndef __BLACKFIN_UACCESS_H
  10 #define __BLACKFIN_UACCESS_H
  11
  12 /*
  13  * User space memory access functions
  14  */
  15 #include <linux/sched.h>
  16 #include <linux/mm.h>
  17 #include <linux/string.h>
  18
  19 #include <asm/segment.h>
  20 #include <asm/sections.h>
  21
  22 #define get_ds()        (KERNEL_DS)
  23 #define get_fs()        (current_thread_info()->addr_limit)
  24
  25 static inline void set_fs(mm_segment_t fs)
  26 {
  27         current_thread_info()->addr_limit = fs;
  28 }
  29
  30 #define segment_eq(a, b) ((a) == (b))
  31
  32 #define VERIFY_READ     0
  33 #define VERIFY_WRITE    1
  34
  35 #define access_ok(type, addr, size) _access_ok((unsigned long)(addr), (size))
  36
  37 /*
  38  * The fs value determines whether argument validity checking should be
  39  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  40  * get_fs() == KERNEL_DS, checking is bypassed.
  41  */
  42
  43 #ifndef CONFIG_ACCESS_CHECK
  44 static inline int _access_ok(unsigned long addr, unsigned long size) { return 1; }
  45 #else
  46 extern int _access_ok(unsigned long addr, unsigned long size);
  47 #endif
  48
  49 /*
  50  * The exception table consists of pairs of addresses: the first is the
  51  * address of an instruction that is allowed to fault, and the second is
  52  * the address at which the program should continue.  No registers are
  53  * modified, so it is entirely up to the continuation code to figure out
  54  * what to do.
  55  *
  56  * All the routines below use bits of fixup code that are out of line
  57  * with the main instruction path.  This means when everything is well,
  58  * we don't even have to jump over them.  Further, they do not intrude
  59  * on our cache or tlb entries.
  60  */
  61
  62 struct exception_table_entry {
  63         unsigned long insn, fixup;
  64 };
  65
  66 /*
  67  * These are the main single-value transfer routines.  They automatically
  68  * use the right size if we just have the right pointer type.
  69  */
  70
  71 #define put_user(x, p)                                          \
  72         ({                                                      \
  73                 int _err = 0;                                   \
  74                 typeof(*(p)) _x = (x);                          \
  75                 typeof(*(p)) __user *_p = (p);                  \
  76                 if (!access_ok(VERIFY_WRITE, _p, sizeof(*(_p)))) {\
  77                         _err = -EFAULT;                         \
  78                 }                                               \
  79                 else {                                          \
  80                 switch (sizeof (*(_p))) {                       \
  81                 case 1:                                         \
  82                         __put_user_asm(_x, _p, B);              \
  83                         break;                                  \
  84                 case 2:                                         \
  85                         __put_user_asm(_x, _p, W);              \
  86                         break;                                  \
  87                 case 4:                                         \
  88                         __put_user_asm(_x, _p,  );              \
  89                         break;                                  \
  90                 case 8: {                                       \
  91                         long _xl, _xh;                          \
  92                         _xl = ((__force long *)&_x)[0];         \
  93                         _xh = ((__force long *)&_x)[1];         \
  94                         __put_user_asm(_xl, ((__force long __user *)_p)+0, );\
  95                         __put_user_asm(_xh, ((__force long __user *)_p)+1, );\
  96                 } break;                                        \
  97                 default:                                        \
  98                         _err = __put_user_bad();                \
  99                         break;                                  \
 100                 }                                               \
 101                 }                                               \
 102                 _err;                                           \
 103         })
 104
 105 #define __put_user(x, p) put_user(x, p)
 106 static inline int bad_user_access_length(void)
 107 {
 108         panic("bad_user_access_length");
 109         return -1;
 110 }
 111
 112 #define __put_user_bad() (printk(KERN_INFO "put_user_bad %s:%d %s\n",\
 113                            __FILE__, __LINE__, __func__),\
 114                            bad_user_access_length(), (-EFAULT))
 115
 116 /*
 117  * Tell gcc we read from memory instead of writing: this is because
 118  * we do not write to any memory gcc knows about, so there are no
 119  * aliasing issues.
 120  */
 121
 122 #define __ptr(x) ((unsigned long __force *)(x))
 123
 124 #define __put_user_asm(x, p, bhw)                       \
 125         __asm__ (#bhw"[%1] = %0;\n\t"                   \
 126                  : /* no outputs */                     \
 127                  :"d" (x), "a" (__ptr(p)) : "memory")
 128
 129 #define get_user(x, ptr)                                        \
 130 ({                                                              \
 131         int _err = 0;                                           \
 132         unsigned long _val = 0;                                 \
 133         const typeof(*(ptr)) __user *_p = (ptr);                \
 134         const size_t ptr_size = sizeof(*(_p));                  \
 135         if (likely(access_ok(VERIFY_READ, _p, ptr_size))) {     \
 136                 BUILD_BUG_ON(ptr_size >= 8);                    \
 137                 switch (ptr_size) {                             \
 138                 case 1:                                         \
 139                         __get_user_asm(_val, _p, B, (Z));       \
 140                         break;                                  \
 141                 case 2:                                         \
 142                         __get_user_asm(_val, _p, W, (Z));       \
 143                         break;                                  \
 144                 case 4:                                         \
 145                         __get_user_asm(_val, _p,  , );          \
 146                         break;                                  \
 147                 }                                               \
 148         } else                                                  \
 149                 _err = -EFAULT;                                 \
 150         x = (__force typeof(*(ptr)))_val;                       \
 151         _err;                                                   \
 152 })
 153
 154 #define __get_user(x, p) get_user(x, p)
 155
 156 #define __get_user_bad() (bad_user_access_length(), (-EFAULT))
 157
 158 #define __get_user_asm(x, ptr, bhw, option)     \
 159 ({                                              \
 160         __asm__ __volatile__ (                  \
 161                 "%0 =" #bhw "[%1]" #option ";"  \
 162                 : "=d" (x)                      \
 163                 : "a" (__ptr(ptr)));            \
 164 })
 165
 166 #define __copy_from_user(to, from, n) copy_from_user(to, from, n)
 167 #define __copy_to_user(to, from, n) copy_to_user(to, from, n)
 168 #define __copy_to_user_inatomic __copy_to_user
 169 #define __copy_from_user_inatomic __copy_from_user
 170
 171 static inline unsigned long __must_check
 172 copy_from_user(void *to, const void __user *from, unsigned long n)
 173 {
 174         if (likely(access_ok(VERIFY_READ, from, n))) {
 175                 memcpy(to, (const void __force *)from, n);
 176                 return 0;
 177         }
 178         memset(to, 0, n);
 179         return n;
 180 }
 181
 182 static inline unsigned long __must_check
 183 copy_to_user(void __user *to, const void *from, unsigned long n)
 184 {
 185         if (access_ok(VERIFY_WRITE, to, n))
 186                 memcpy((void __force *)to, from, n);
 187         else
 188                 return n;
 189         SSYNC();
 190         return 0;
 191 }
 192
 193 /*
 194  * Copy a null terminated string from userspace.
 195  */
 196
 197 static inline long __must_check
 198 strncpy_from_user(char *dst, const char __user *src, long count)
 199 {
 200         char *tmp;
 201         if (!access_ok(VERIFY_READ, src, 1))
 202                 return -EFAULT;
 203         strncpy(dst, (const char __force *)src, count);
 204         for (tmp = dst; *tmp && count > 0; tmp++, count--) ;
 205         return (tmp - dst);
 206 }
 207
 208 /*
 209  * Get the size of a string in user space.
 210  *   src: The string to measure
 211  *     n: The maximum valid length
 212  *
 213  * Get the size of a NUL-terminated string in user space.
 214  *
 215  * Returns the size of the string INCLUDING the terminating NUL.
 216  * On exception, returns 0.
 217  * If the string is too long, returns a value greater than n.
 218  */
 219 static inline long __must_check strnlen_user(const char __user *src, long n)
 220 {
 221         if (!access_ok(VERIFY_READ, src, 1))
 222                 return 0;
 223         return strnlen((const char __force *)src, n) + 1;
 224 }
 225
 226 static inline long __must_check strlen_user(const char __user *src)
 227 {
 228         if (!access_ok(VERIFY_READ, src, 1))
 229                 return 0;
 230         return strlen((const char __force *)src) + 1;
 231 }
 232
 233 /*
 234  * Zero Userspace
 235  */
 236
 237 static inline unsigned long __must_check
 238 __clear_user(void __user *to, unsigned long n)
 239 {
 240         if (!access_ok(VERIFY_WRITE, to, n))
 241                 return n;
 242         memset((void __force *)to, 0, n);
 243         return 0;
 244 }
 245
 246 #define clear_user(to, n) __clear_user(to, n)
 247
 248 /* How to interpret these return values:
 249  *      CORE:      can be accessed by core load or dma memcpy
 250  *      CORE_ONLY: can only be accessed by core load
 251  *      DMA:       can only be accessed by dma memcpy
 252  *      IDMA:      can only be accessed by interprocessor dma memcpy (BF561)
 253  *      ITEST:     can be accessed by isram memcpy or dma memcpy
 254  */
 255 enum {
 256         BFIN_MEM_ACCESS_CORE = 0,
 257         BFIN_MEM_ACCESS_CORE_ONLY,
 258         BFIN_MEM_ACCESS_DMA,
 259         BFIN_MEM_ACCESS_IDMA,
 260         BFIN_MEM_ACCESS_ITEST,
 261 };
 262 /**
 263  *      bfin_mem_access_type() - what kind of memory access is required
 264  *      @addr:   the address to check
 265  *      @size:   number of bytes needed
 266  *      @return: <0 is error, >=0 is BFIN_MEM_ACCESS_xxx enum (see above)
 267  */
 268 int bfin_mem_access_type(unsigned long addr, unsigned long size);
 269
 270 #endif                          /* _BLACKFIN_UACCESS_H */