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 access_ok(type, addr, size) _access_ok((unsigned long)(addr), (size))
  33
  34 /*
  35  * The fs value determines whether argument validity checking should be
  36  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  37  * get_fs() == KERNEL_DS, checking is bypassed.
  38  */
  39
  40 #ifndef CONFIG_ACCESS_CHECK
  41 static inline int _access_ok(unsigned long addr, unsigned long size) { return 1; }
  42 #else
  43 extern int _access_ok(unsigned long addr, unsigned long size);
  44 #endif
  45
  46 /*
  47  * The exception table consists of pairs of addresses: the first is the
  48  * address of an instruction that is allowed to fault, and the second is
  49  * the address at which the program should continue.  No registers are
  50  * modified, so it is entirely up to the continuation code to figure out
  51  * what to do.
  52  *
  53  * All the routines below use bits of fixup code that are out of line
  54  * with the main instruction path.  This means when everything is well,
  55  * we don't even have to jump over them.  Further, they do not intrude
  56  * on our cache or tlb entries.
  57  */
  58
  59 struct exception_table_entry {
  60         unsigned long insn, fixup;
  61 };
  62
  63 /*
  64  * These are the main single-value transfer routines.  They automatically
  65  * use the right size if we just have the right pointer type.
  66  */
  67
  68 #define put_user(x, p)                                          \
  69         ({                                                      \
  70                 int _err = 0;                                   \
  71                 typeof(*(p)) _x = (x);                          \
  72                 typeof(*(p)) __user *_p = (p);                  \
  73                 if (!access_ok(VERIFY_WRITE, _p, sizeof(*(_p)))) {\
  74                         _err = -EFAULT;                         \
  75                 }                                               \
  76                 else {                                          \
  77                 switch (sizeof (*(_p))) {                       \
  78                 case 1:                                         \
  79                         __put_user_asm(_x, _p, B);              \
  80                         break;                                  \
  81                 case 2:                                         \
  82                         __put_user_asm(_x, _p, W);              \
  83                         break;                                  \
  84                 case 4:                                         \
  85                         __put_user_asm(_x, _p,  );              \
  86                         break;                                  \
  87                 case 8: {                                       \
  88                         long _xl, _xh;                          \
  89                         _xl = ((__force long *)&_x)[0];         \
  90                         _xh = ((__force long *)&_x)[1];         \
  91                         __put_user_asm(_xl, ((__force long __user *)_p)+0, );\
  92                         __put_user_asm(_xh, ((__force long __user *)_p)+1, );\
  93                 } break;                                        \
  94                 default:                                        \
  95                         _err = __put_user_bad();                \
  96                         break;                                  \
  97                 }                                               \
  98                 }                                               \
  99                 _err;                                           \
 100         })
 101
 102 #define __put_user(x, p) put_user(x, p)
 103 static inline int bad_user_access_length(void)
 104 {
 105         panic("bad_user_access_length");
 106         return -1;
 107 }
 108
 109 #define __put_user_bad() (printk(KERN_INFO "put_user_bad %s:%d %s\n",\
 110                            __FILE__, __LINE__, __func__),\
 111                            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 __force *)(x))
 120
 121 #define __put_user_asm(x, p, bhw)                       \
 122         __asm__ (#bhw"[%1] = %0;\n\t"                   \
 123                  : /* no outputs */                     \
 124                  :"d" (x), "a" (__ptr(p)) : "memory")
 125
 126 #define get_user(x, ptr)                                        \
 127 ({                                                              \
 128         int _err = 0;                                           \
 129         unsigned long _val = 0;                                 \
 130         const typeof(*(ptr)) __user *_p = (ptr);                \
 131         const size_t ptr_size = sizeof(*(_p));                  \
 132         if (likely(access_ok(VERIFY_READ, _p, ptr_size))) {     \
 133                 BUILD_BUG_ON(ptr_size >= 8);                    \
 134                 switch (ptr_size) {                             \
 135                 case 1:                                         \
 136                         __get_user_asm(_val, _p, B, (Z));       \
 137                         break;                                  \
 138                 case 2:                                         \
 139                         __get_user_asm(_val, _p, W, (Z));       \
 140                         break;                                  \
 141                 case 4:                                         \
 142                         __get_user_asm(_val, _p,  , );          \
 143                         break;                                  \
 144                 }                                               \
 145         } else                                                  \
 146                 _err = -EFAULT;                                 \
 147         x = (__force typeof(*(ptr)))_val;                       \
 148         _err;                                                   \
 149 })
 150
 151 #define __get_user(x, p) get_user(x, p)
 152
 153 #define __get_user_bad() (bad_user_access_length(), (-EFAULT))
 154
 155 #define __get_user_asm(x, ptr, bhw, option)     \
 156 ({                                              \
 157         __asm__ __volatile__ (                  \
 158                 "%0 =" #bhw "[%1]" #option ";"  \
 159                 : "=d" (x)                      \
 160                 : "a" (__ptr(ptr)));            \
 161 })
 162
 163 #define __copy_to_user_inatomic __copy_to_user
 164 #define __copy_from_user_inatomic __copy_from_user
 165
 166 static inline unsigned long __must_check
 167 __copy_from_user(void *to, const void __user *from, unsigned long n)
 168 {
 169         memcpy(to, (const void __force *)from, n);
 170         return 0;
 171 }
 172
 173 static inline unsigned long __must_check
 174 __copy_to_user(void __user *to, const void *from, unsigned long n)
 175 {
 176         memcpy((void __force *)to, from, n);
 177         SSYNC();
 178         return 0;
 179 }
 180
 181 static inline unsigned long __must_check
 182 copy_from_user(void *to, const void __user *from, unsigned long n)
 183 {
 184         if (likely(access_ok(VERIFY_READ, from, n)))
 185                 return __copy_from_user(to, from, n);
 186         memset(to, 0, n);
 187         return n;
 188 }
 189
 190 static inline unsigned long __must_check
 191 copy_to_user(void __user *to, const void *from, unsigned long n)
 192 {
 193         if (likely(access_ok(VERIFY_WRITE, to, n)))
 194                 return __copy_to_user(to, from, n);
 195         return n;
 196 }
 197
 198 /*
 199  * Copy a null terminated string from userspace.
 200  */
 201
 202 static inline long __must_check
 203 strncpy_from_user(char *dst, const char __user *src, long count)
 204 {
 205         char *tmp;
 206         if (!access_ok(VERIFY_READ, src, 1))
 207                 return -EFAULT;
 208         strncpy(dst, (const char __force *)src, count);
 209         for (tmp = dst; *tmp && count > 0; tmp++, count--) ;
 210         return (tmp - dst);
 211 }
 212
 213 /*
 214  * Get the size of a string in user space.
 215  *   src: The string to measure
 216  *     n: The maximum valid length
 217  *
 218  * Get the size of a NUL-terminated string in user space.
 219  *
 220  * Returns the size of the string INCLUDING the terminating NUL.
 221  * On exception, returns 0.
 222  * If the string is too long, returns a value greater than n.
 223  */
 224 static inline long __must_check strnlen_user(const char __user *src, long n)
 225 {
 226         if (!access_ok(VERIFY_READ, src, 1))
 227                 return 0;
 228         return strnlen((const char __force *)src, n) + 1;
 229 }
 230
 231 static inline long __must_check strlen_user(const char __user *src)
 232 {
 233         if (!access_ok(VERIFY_READ, src, 1))
 234                 return 0;
 235         return strlen((const char __force *)src) + 1;
 236 }
 237
 238 /*
 239  * Zero Userspace
 240  */
 241
 242 static inline unsigned long __must_check
 243 __clear_user(void __user *to, unsigned long n)
 244 {
 245         if (!access_ok(VERIFY_WRITE, to, n))
 246                 return n;
 247         memset((void __force *)to, 0, n);
 248         return 0;
 249 }
 250
 251 #define clear_user(to, n) __clear_user(to, n)
 252
 253 /* How to interpret these return values:
 254  *      CORE:      can be accessed by core load or dma memcpy
 255  *      CORE_ONLY: can only be accessed by core load
 256  *      DMA:       can only be accessed by dma memcpy
 257  *      IDMA:      can only be accessed by interprocessor dma memcpy (BF561)
 258  *      ITEST:     can be accessed by isram memcpy or dma memcpy
 259  */
 260 enum {
 261         BFIN_MEM_ACCESS_CORE = 0,
 262         BFIN_MEM_ACCESS_CORE_ONLY,
 263         BFIN_MEM_ACCESS_DMA,
 264         BFIN_MEM_ACCESS_IDMA,
 265         BFIN_MEM_ACCESS_ITEST,
 266 };
 267 /**
 268  *      bfin_mem_access_type() - what kind of memory access is required
 269  *      @addr:   the address to check
 270  *      @size:   number of bytes needed
 271  *      @return: <0 is error, >=0 is BFIN_MEM_ACCESS_xxx enum (see above)
 272  */
 273 int bfin_mem_access_type(unsigned long addr, unsigned long size);
 274
 275 #endif                          /* _BLACKFIN_UACCESS_H */