arch/metag/include/asm/uaccess.h

   1 #ifndef __METAG_UACCESS_H
   2 #define __METAG_UACCESS_H
   3
   4 /*
   5  * User space memory access functions
   6  */
   7
   8 /*
   9  * The fs value determines whether argument validity checking should be
  10  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  11  * get_fs() == KERNEL_DS, checking is bypassed.
  12  *
  13  * For historical reasons, these macros are grossly misnamed.
  14  */
  15
  16 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  17
  18 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  19 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
  20
  21 #define get_ds()        (KERNEL_DS)
  22 #define get_fs()        (current_thread_info()->addr_limit)
  23 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  24
  25 #define segment_eq(a, b)        ((a).seg == (b).seg)
  26
  27 static inline int __access_ok(unsigned long addr, unsigned long size)
  28 {
  29         /*
  30          * Allow access to the user mapped memory area, but not the system area
  31          * before it. The check extends to the top of the address space when
  32          * kernel access is allowed (there's no real reason to user copy to the
  33          * system area in any case).
  34          */
  35         if (likely(addr >= META_MEMORY_BASE && addr < get_fs().seg &&
  36                    size <= get_fs().seg - addr))
  37                 return true;
  38         /*
  39          * Explicitly allow NULL pointers here. Parts of the kernel such
  40          * as readv/writev use access_ok to validate pointers, but want
  41          * to allow NULL pointers for various reasons. NULL pointers are
  42          * safe to allow through because the first page is not mappable on
  43          * Meta.
  44          */
  45         if (!addr)
  46                 return true;
  47         /* Allow access to core code memory area... */
  48         if (addr >= LINCORE_CODE_BASE && addr <= LINCORE_CODE_LIMIT &&
  49             size <= LINCORE_CODE_LIMIT + 1 - addr)
  50                 return true;
  51         /* ... but no other areas. */
  52         return false;
  53 }
  54
  55 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),  \
  56                                                 (unsigned long)(size))
  57
  58 #include <asm/extable.h>
  59
  60 /*
  61  * These are the main single-value transfer routines.  They automatically
  62  * use the right size if we just have the right pointer type.
  63  */
  64
  65 #define put_user(x, ptr) \
  66         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  67 #define __put_user(x, ptr) \
  68         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  69
  70 extern void __put_user_bad(void);
  71
  72 #define __put_user_nocheck(x, ptr, size)                \
  73 ({                                                      \
  74         long __pu_err;                                  \
  75         __put_user_size((x), (ptr), (size), __pu_err);  \
  76         __pu_err;                                       \
  77 })
  78
  79 #define __put_user_check(x, ptr, size)                          \
  80 ({                                                              \
  81         long __pu_err = -EFAULT;                                \
  82         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
  83         if (access_ok(VERIFY_WRITE, __pu_addr, size))           \
  84                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
  85         __pu_err;                                               \
  86 })
  87
  88 extern long __put_user_asm_b(unsigned int x, void __user *addr);
  89 extern long __put_user_asm_w(unsigned int x, void __user *addr);
  90 extern long __put_user_asm_d(unsigned int x, void __user *addr);
  91 extern long __put_user_asm_l(unsigned long long x, void __user *addr);
  92
  93 #define __put_user_size(x, ptr, size, retval)                           \
  94 do {                                                                    \
  95         retval = 0;                                                     \
  96         switch (size) {                                                 \
  97         case 1:                                                         \
  98                 retval = __put_user_asm_b((__force unsigned int)x, ptr);\
  99                 break;                                                  \
 100         case 2:                                                         \
 101                 retval = __put_user_asm_w((__force unsigned int)x, ptr);\
 102                 break;                                                  \
 103         case 4:                                                         \
 104                 retval = __put_user_asm_d((__force unsigned int)x, ptr);\
 105                 break;                                                  \
 106         case 8:                                                         \
 107                 retval = __put_user_asm_l((__force unsigned long long)x,\
 108                                           ptr);                         \
 109                 break;                                                  \
 110         default:                                                        \
 111                 __put_user_bad();                                       \
 112         }                                                               \
 113 } while (0)
 114
 115 #define get_user(x, ptr) \
 116         __get_user_check((x), (ptr), sizeof(*(ptr)))
 117 #define __get_user(x, ptr) \
 118         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 119
 120 extern long __get_user_bad(void);
 121
 122 #define __get_user_nocheck(x, ptr, size)                        \
 123 ({                                                              \
 124         long __gu_err;                                          \
 125         long long __gu_val;                                     \
 126         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 127         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 128         __gu_err;                                               \
 129 })
 130
 131 #define __get_user_check(x, ptr, size)                                  \
 132 ({                                                                      \
 133         long __gu_err = -EFAULT;                                        \
 134         long long __gu_val = 0;                                         \
 135         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 136         if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 137                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 138         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 139         __gu_err;                                                       \
 140 })
 141
 142 extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
 143 extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
 144 extern unsigned int __get_user_asm_d(const void __user *addr, long *err);
 145 extern unsigned long long __get_user_asm_l(const void __user *addr, long *err);
 146
 147 #define __get_user_size(x, ptr, size, retval)                   \
 148 do {                                                            \
 149         retval = 0;                                             \
 150         switch (size) {                                         \
 151         case 1:                                                 \
 152                 x = __get_user_asm_b(ptr, &retval); break;      \
 153         case 2:                                                 \
 154                 x = __get_user_asm_w(ptr, &retval); break;      \
 155         case 4:                                                 \
 156                 x = __get_user_asm_d(ptr, &retval); break;      \
 157         case 8:                                                 \
 158                 x = __get_user_asm_l(ptr, &retval); break;      \
 159         default:                                                \
 160                 (x) = __get_user_bad();                         \
 161         }                                                       \
 162 } while (0)
 163
 164 /*
 165  * Copy a null terminated string from userspace.
 166  *
 167  * Must return:
 168  * -EFAULT              for an exception
 169  * count                if we hit the buffer limit
 170  * bytes copied         if we hit a null byte
 171  * (without the null byte)
 172  */
 173
 174 extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
 175                                              long count);
 176
 177 static inline long
 178 strncpy_from_user(char *dst, const char __user *src, long count)
 179 {
 180         if (!access_ok(VERIFY_READ, src, 1))
 181                 return -EFAULT;
 182         return __strncpy_from_user(dst, src, count);
 183 }
 184 /*
 185  * Return the size of a string (including the ending 0)
 186  *
 187  * Return 0 on exception, a value greater than N if too long
 188  */
 189 extern long __must_check strnlen_user(const char __user *src, long count);
 190
 191 extern unsigned long raw_copy_from_user(void *to, const void __user *from,
 192                                         unsigned long n);
 193 extern unsigned long raw_copy_to_user(void __user *to, const void *from,
 194                                       unsigned long n);
 195
 196 /*
 197  * Zero Userspace
 198  */
 199
 200 extern unsigned long __must_check __do_clear_user(void __user *to,
 201                                                   unsigned long n);
 202
 203 static inline unsigned long clear_user(void __user *to, unsigned long n)
 204 {
 205         if (access_ok(VERIFY_WRITE, to, n))
 206                 return __do_clear_user(to, n);
 207         return n;
 208 }
 209
 210 #define __clear_user(to, n)            __do_clear_user(to, n)
 211
 212 #endif /* _METAG_UACCESS_H */