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 #include <linux/sched.h>
   8
   9 /*
  10  * The fs value determines whether argument validity checking should be
  11  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  12  * get_fs() == KERNEL_DS, checking is bypassed.
  13  *
  14  * For historical reasons, these macros are grossly misnamed.
  15  */
  16
  17 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  18
  19 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  20 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
  21
  22 #define get_ds()        (KERNEL_DS)
  23 #define get_fs()        (current_thread_info()->addr_limit)
  24 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  25
  26 #define segment_eq(a, b)        ((a).seg == (b).seg)
  27
  28 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
  29 /*
  30  * Explicitly allow NULL pointers here. Parts of the kernel such
  31  * as readv/writev use access_ok to validate pointers, but want
  32  * to allow NULL pointers for various reasons. NULL pointers are
  33  * safe to allow through because the first page is not mappable on
  34  * Meta.
  35  *
  36  * We also wish to avoid letting user code access the system area
  37  * and the kernel half of the address space.
  38  */
  39 #define __user_bad(addr, size) (((addr) > 0 && (addr) < META_MEMORY_BASE) || \
  40                                 ((addr) > PAGE_OFFSET &&                \
  41                                  (addr) < LINCORE_BASE))
  42
  43 static inline int __access_ok(unsigned long addr, unsigned long size)
  44 {
  45         return __kernel_ok || !__user_bad(addr, size);
  46 }
  47
  48 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),  \
  49                                                 (unsigned long)(size))
  50
  51 static inline int verify_area(int type, const void *addr, unsigned long size)
  52 {
  53         return access_ok(type, addr, size) ? 0 : -EFAULT;
  54 }
  55
  56 /*
  57  * The exception table consists of pairs of addresses: the first is the
  58  * address of an instruction that is allowed to fault, and the second is
  59  * the address at which the program should continue.  No registers are
  60  * modified, so it is entirely up to the continuation code to figure out
  61  * what to do.
  62  *
  63  * All the routines below use bits of fixup code that are out of line
  64  * with the main instruction path.  This means when everything is well,
  65  * we don't even have to jump over them.  Further, they do not intrude
  66  * on our cache or tlb entries.
  67  */
  68 struct exception_table_entry {
  69         unsigned long insn, fixup;
  70 };
  71
  72 extern int fixup_exception(struct pt_regs *regs);
  73
  74 /*
  75  * These are the main single-value transfer routines.  They automatically
  76  * use the right size if we just have the right pointer type.
  77  */
  78
  79 #define put_user(x, ptr) \
  80         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  81 #define __put_user(x, ptr) \
  82         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  83
  84 extern void __put_user_bad(void);
  85
  86 #define __put_user_nocheck(x, ptr, size)                \
  87 ({                                                      \
  88         long __pu_err;                                  \
  89         __put_user_size((x), (ptr), (size), __pu_err);  \
  90         __pu_err;                                       \
  91 })
  92
  93 #define __put_user_check(x, ptr, size)                          \
  94 ({                                                              \
  95         long __pu_err = -EFAULT;                                \
  96         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
  97         if (access_ok(VERIFY_WRITE, __pu_addr, size))           \
  98                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
  99         __pu_err;                                               \
 100 })
 101
 102 extern long __put_user_asm_b(unsigned int x, void __user *addr);
 103 extern long __put_user_asm_w(unsigned int x, void __user *addr);
 104 extern long __put_user_asm_d(unsigned int x, void __user *addr);
 105 extern long __put_user_asm_l(unsigned long long x, void __user *addr);
 106
 107 #define __put_user_size(x, ptr, size, retval)                           \
 108 do {                                                                    \
 109         retval = 0;                                                     \
 110         switch (size) {                                                 \
 111         case 1:                                                         \
 112                 retval = __put_user_asm_b((__force unsigned int)x, ptr);\
 113                 break;                                                  \
 114         case 2:                                                         \
 115                 retval = __put_user_asm_w((__force unsigned int)x, ptr);\
 116                 break;                                                  \
 117         case 4:                                                         \
 118                 retval = __put_user_asm_d((__force unsigned int)x, ptr);\
 119                 break;                                                  \
 120         case 8:                                                         \
 121                 retval = __put_user_asm_l((__force unsigned long long)x,\
 122                                           ptr);                         \
 123                 break;                                                  \
 124         default:                                                        \
 125                 __put_user_bad();                                       \
 126         }                                                               \
 127 } while (0)
 128
 129 #define get_user(x, ptr) \
 130         __get_user_check((x), (ptr), sizeof(*(ptr)))
 131 #define __get_user(x, ptr) \
 132         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 133
 134 extern long __get_user_bad(void);
 135
 136 #define __get_user_nocheck(x, ptr, size)                        \
 137 ({                                                              \
 138         long __gu_err, __gu_val;                                \
 139         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 140         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 141         __gu_err;                                               \
 142 })
 143
 144 #define __get_user_check(x, ptr, size)                                  \
 145 ({                                                                      \
 146         long __gu_err = -EFAULT, __gu_val = 0;                          \
 147         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 148         if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 149                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 150         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 151         __gu_err;                                                       \
 152 })
 153
 154 extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
 155 extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
 156 extern unsigned int __get_user_asm_d(const void __user *addr, long *err);
 157
 158 #define __get_user_size(x, ptr, size, retval)                   \
 159 do {                                                            \
 160         retval = 0;                                             \
 161         switch (size) {                                         \
 162         case 1:                                                 \
 163                 x = __get_user_asm_b(ptr, &retval); break;      \
 164         case 2:                                                 \
 165                 x = __get_user_asm_w(ptr, &retval); break;      \
 166         case 4:                                                 \
 167                 x = __get_user_asm_d(ptr, &retval); break;      \
 168         default:                                                \
 169                 (x) = __get_user_bad();                         \
 170         }                                                       \
 171 } while (0)
 172
 173 /*
 174  * Copy a null terminated string from userspace.
 175  *
 176  * Must return:
 177  * -EFAULT              for an exception
 178  * count                if we hit the buffer limit
 179  * bytes copied         if we hit a null byte
 180  * (without the null byte)
 181  */
 182
 183 extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
 184                                              long count);
 185
 186 #define strncpy_from_user(dst, src, count) __strncpy_from_user(dst, src, count)
 187
 188 /*
 189  * Return the size of a string (including the ending 0)
 190  *
 191  * Return 0 on exception, a value greater than N if too long
 192  */
 193 extern long __must_check strnlen_user(const char __user *src, long count);
 194
 195 #define strlen_user(str) strnlen_user(str, 32767)
 196
 197 extern unsigned long __must_check __copy_user_zeroing(void *to,
 198                                                       const void __user *from,
 199                                                       unsigned long n);
 200
 201 static inline unsigned long
 202 copy_from_user(void *to, const void __user *from, unsigned long n)
 203 {
 204         if (likely(access_ok(VERIFY_READ, from, n)))
 205                 return __copy_user_zeroing(to, from, n);
 206         memset(to, 0, n);
 207         return n;
 208 }
 209
 210 #define __copy_from_user(to, from, n) __copy_user_zeroing(to, from, n)
 211 #define __copy_from_user_inatomic __copy_from_user
 212
 213 extern unsigned long __must_check __copy_user(void __user *to,
 214                                               const void *from,
 215                                               unsigned long n);
 216
 217 static inline unsigned long copy_to_user(void __user *to, const void *from,
 218                                          unsigned long n)
 219 {
 220         if (access_ok(VERIFY_WRITE, to, n))
 221                 return __copy_user(to, from, n);
 222         return n;
 223 }
 224
 225 #define __copy_to_user(to, from, n) __copy_user(to, from, n)
 226 #define __copy_to_user_inatomic __copy_to_user
 227
 228 /*
 229  * Zero Userspace
 230  */
 231
 232 extern unsigned long __must_check __do_clear_user(void __user *to,
 233                                                   unsigned long n);
 234
 235 static inline unsigned long clear_user(void __user *to, unsigned long n)
 236 {
 237         if (access_ok(VERIFY_WRITE, to, n))
 238                 return __do_clear_user(to, n);
 239         return n;
 240 }
 241
 242 #define __clear_user(to, n)            __do_clear_user(to, n)
 243
 244 #endif /* _METAG_UACCESS_H */