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 #define __kernel_ok (uaccess_kernel())
  28 /*
  29  * Explicitly allow NULL pointers here. Parts of the kernel such
  30  * as readv/writev use access_ok to validate pointers, but want
  31  * to allow NULL pointers for various reasons. NULL pointers are
  32  * safe to allow through because the first page is not mappable on
  33  * Meta.
  34  *
  35  * We also wish to avoid letting user code access the system area
  36  * and the kernel half of the address space.
  37  */
  38 #define __user_bad(addr, size) (((addr) > 0 && (addr) < META_MEMORY_BASE) || \
  39                                 ((addr) > PAGE_OFFSET &&                \
  40                                  (addr) < LINCORE_BASE))
  41
  42 static inline int __access_ok(unsigned long addr, unsigned long size)
  43 {
  44         return __kernel_ok || !__user_bad(addr, size);
  45 }
  46
  47 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),  \
  48                                                 (unsigned long)(size))
  49
  50 #include <asm/extable.h>
  51
  52 /*
  53  * These are the main single-value transfer routines.  They automatically
  54  * use the right size if we just have the right pointer type.
  55  */
  56
  57 #define put_user(x, ptr) \
  58         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  59 #define __put_user(x, ptr) \
  60         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  61
  62 extern void __put_user_bad(void);
  63
  64 #define __put_user_nocheck(x, ptr, size)                \
  65 ({                                                      \
  66         long __pu_err;                                  \
  67         __put_user_size((x), (ptr), (size), __pu_err);  \
  68         __pu_err;                                       \
  69 })
  70
  71 #define __put_user_check(x, ptr, size)                          \
  72 ({                                                              \
  73         long __pu_err = -EFAULT;                                \
  74         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
  75         if (access_ok(VERIFY_WRITE, __pu_addr, size))           \
  76                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
  77         __pu_err;                                               \
  78 })
  79
  80 extern long __put_user_asm_b(unsigned int x, void __user *addr);
  81 extern long __put_user_asm_w(unsigned int x, void __user *addr);
  82 extern long __put_user_asm_d(unsigned int x, void __user *addr);
  83 extern long __put_user_asm_l(unsigned long long x, void __user *addr);
  84
  85 #define __put_user_size(x, ptr, size, retval)                           \
  86 do {                                                                    \
  87         retval = 0;                                                     \
  88         switch (size) {                                                 \
  89         case 1:                                                         \
  90                 retval = __put_user_asm_b((__force unsigned int)x, ptr);\
  91                 break;                                                  \
  92         case 2:                                                         \
  93                 retval = __put_user_asm_w((__force unsigned int)x, ptr);\
  94                 break;                                                  \
  95         case 4:                                                         \
  96                 retval = __put_user_asm_d((__force unsigned int)x, ptr);\
  97                 break;                                                  \
  98         case 8:                                                         \
  99                 retval = __put_user_asm_l((__force unsigned long long)x,\
 100                                           ptr);                         \
 101                 break;                                                  \
 102         default:                                                        \
 103                 __put_user_bad();                                       \
 104         }                                                               \
 105 } while (0)
 106
 107 #define get_user(x, ptr) \
 108         __get_user_check((x), (ptr), sizeof(*(ptr)))
 109 #define __get_user(x, ptr) \
 110         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 111
 112 extern long __get_user_bad(void);
 113
 114 #define __get_user_nocheck(x, ptr, size)                        \
 115 ({                                                              \
 116         long __gu_err, __gu_val;                                \
 117         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 118         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 119         __gu_err;                                               \
 120 })
 121
 122 #define __get_user_check(x, ptr, size)                                  \
 123 ({                                                                      \
 124         long __gu_err = -EFAULT, __gu_val = 0;                          \
 125         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 126         if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 127                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 128         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 129         __gu_err;                                                       \
 130 })
 131
 132 extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
 133 extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
 134 extern unsigned int __get_user_asm_d(const void __user *addr, long *err);
 135
 136 #define __get_user_size(x, ptr, size, retval)                   \
 137 do {                                                            \
 138         retval = 0;                                             \
 139         switch (size) {                                         \
 140         case 1:                                                 \
 141                 x = __get_user_asm_b(ptr, &retval); break;      \
 142         case 2:                                                 \
 143                 x = __get_user_asm_w(ptr, &retval); break;      \
 144         case 4:                                                 \
 145                 x = __get_user_asm_d(ptr, &retval); break;      \
 146         default:                                                \
 147                 (x) = __get_user_bad();                         \
 148         }                                                       \
 149 } while (0)
 150
 151 /*
 152  * Copy a null terminated string from userspace.
 153  *
 154  * Must return:
 155  * -EFAULT              for an exception
 156  * count                if we hit the buffer limit
 157  * bytes copied         if we hit a null byte
 158  * (without the null byte)
 159  */
 160
 161 extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
 162                                              long count);
 163
 164 #define strncpy_from_user(dst, src, count) __strncpy_from_user(dst, src, count)
 165
 166 /*
 167  * Return the size of a string (including the ending 0)
 168  *
 169  * Return 0 on exception, a value greater than N if too long
 170  */
 171 extern long __must_check strnlen_user(const char __user *src, long count);
 172
 173 #define strlen_user(str) strnlen_user(str, 32767)
 174
 175 extern unsigned long raw_copy_from_user(void *to, const void __user *from,
 176                                         unsigned long n);
 177 extern unsigned long raw_copy_to_user(void __user *to, const void *from,
 178                                       unsigned long n);
 179
 180 /*
 181  * Zero Userspace
 182  */
 183
 184 extern unsigned long __must_check __do_clear_user(void __user *to,
 185                                                   unsigned long n);
 186
 187 static inline unsigned long clear_user(void __user *to, unsigned long n)
 188 {
 189         if (access_ok(VERIFY_WRITE, to, n))
 190                 return __do_clear_user(to, n);
 191         return n;
 192 }
 193
 194 #define __clear_user(to, n)            __do_clear_user(to, n)
 195
 196 #endif /* _METAG_UACCESS_H */