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 static inline int verify_area(int type, const void *addr, unsigned long size)
  51 {
  52         return access_ok(type, addr, size) ? 0 : -EFAULT;
  53 }
  54
  55 /*
  56  * The exception table consists of pairs of addresses: the first is the
  57  * address of an instruction that is allowed to fault, and the second is
  58  * the address at which the program should continue.  No registers are
  59  * modified, so it is entirely up to the continuation code to figure out
  60  * what to do.
  61  *
  62  * All the routines below use bits of fixup code that are out of line
  63  * with the main instruction path.  This means when everything is well,
  64  * we don't even have to jump over them.  Further, they do not intrude
  65  * on our cache or tlb entries.
  66  */
  67 struct exception_table_entry {
  68         unsigned long insn, fixup;
  69 };
  70
  71 extern int fixup_exception(struct pt_regs *regs);
  72
  73 /*
  74  * These are the main single-value transfer routines.  They automatically
  75  * use the right size if we just have the right pointer type.
  76  */
  77
  78 #define put_user(x, ptr) \
  79         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  80 #define __put_user(x, ptr) \
  81         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  82
  83 extern void __put_user_bad(void);
  84
  85 #define __put_user_nocheck(x, ptr, size)                \
  86 ({                                                      \
  87         long __pu_err;                                  \
  88         __put_user_size((x), (ptr), (size), __pu_err);  \
  89         __pu_err;                                       \
  90 })
  91
  92 #define __put_user_check(x, ptr, size)                          \
  93 ({                                                              \
  94         long __pu_err = -EFAULT;                                \
  95         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
  96         if (access_ok(VERIFY_WRITE, __pu_addr, size))           \
  97                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
  98         __pu_err;                                               \
  99 })
 100
 101 extern long __put_user_asm_b(unsigned int x, void __user *addr);
 102 extern long __put_user_asm_w(unsigned int x, void __user *addr);
 103 extern long __put_user_asm_d(unsigned int x, void __user *addr);
 104 extern long __put_user_asm_l(unsigned long long x, void __user *addr);
 105
 106 #define __put_user_size(x, ptr, size, retval)                           \
 107 do {                                                                    \
 108         retval = 0;                                                     \
 109         switch (size) {                                                 \
 110         case 1:                                                         \
 111                 retval = __put_user_asm_b((__force unsigned int)x, ptr);\
 112                 break;                                                  \
 113         case 2:                                                         \
 114                 retval = __put_user_asm_w((__force unsigned int)x, ptr);\
 115                 break;                                                  \
 116         case 4:                                                         \
 117                 retval = __put_user_asm_d((__force unsigned int)x, ptr);\
 118                 break;                                                  \
 119         case 8:                                                         \
 120                 retval = __put_user_asm_l((__force unsigned long long)x,\
 121                                           ptr);                         \
 122                 break;                                                  \
 123         default:                                                        \
 124                 __put_user_bad();                                       \
 125         }                                                               \
 126 } while (0)
 127
 128 #define get_user(x, ptr) \
 129         __get_user_check((x), (ptr), sizeof(*(ptr)))
 130 #define __get_user(x, ptr) \
 131         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 132
 133 extern long __get_user_bad(void);
 134
 135 #define __get_user_nocheck(x, ptr, size)                        \
 136 ({                                                              \
 137         long __gu_err, __gu_val;                                \
 138         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 139         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 140         __gu_err;                                               \
 141 })
 142
 143 #define __get_user_check(x, ptr, size)                                  \
 144 ({                                                                      \
 145         long __gu_err = -EFAULT, __gu_val = 0;                          \
 146         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 147         if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 148                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 149         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 150         __gu_err;                                                       \
 151 })
 152
 153 extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
 154 extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
 155 extern unsigned int __get_user_asm_d(const void __user *addr, long *err);
 156
 157 #define __get_user_size(x, ptr, size, retval)                   \
 158 do {                                                            \
 159         retval = 0;                                             \
 160         switch (size) {                                         \
 161         case 1:                                                 \
 162                 x = __get_user_asm_b(ptr, &retval); break;      \
 163         case 2:                                                 \
 164                 x = __get_user_asm_w(ptr, &retval); break;      \
 165         case 4:                                                 \
 166                 x = __get_user_asm_d(ptr, &retval); break;      \
 167         default:                                                \
 168                 (x) = __get_user_bad();                         \
 169         }                                                       \
 170 } while (0)
 171
 172 /*
 173  * Copy a null terminated string from userspace.
 174  *
 175  * Must return:
 176  * -EFAULT              for an exception
 177  * count                if we hit the buffer limit
 178  * bytes copied         if we hit a null byte
 179  * (without the null byte)
 180  */
 181
 182 extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
 183                                              long count);
 184
 185 #define strncpy_from_user(dst, src, count) __strncpy_from_user(dst, src, count)
 186
 187 /*
 188  * Return the size of a string (including the ending 0)
 189  *
 190  * Return 0 on exception, a value greater than N if too long
 191  */
 192 extern long __must_check strnlen_user(const char __user *src, long count);
 193
 194 #define strlen_user(str) strnlen_user(str, 32767)
 195
 196 extern unsigned long __must_check __copy_user_zeroing(void *to,
 197                                                       const void __user *from,
 198                                                       unsigned long n);
 199
 200 static inline unsigned long
 201 copy_from_user(void *to, const void __user *from, unsigned long n)
 202 {
 203         if (likely(access_ok(VERIFY_READ, from, n)))
 204                 return __copy_user_zeroing(to, from, n);
 205         memset(to, 0, n);
 206         return n;
 207 }
 208
 209 #define __copy_from_user(to, from, n) __copy_user_zeroing(to, from, n)
 210 #define __copy_from_user_inatomic __copy_from_user
 211
 212 extern unsigned long __must_check __copy_user(void __user *to,
 213                                               const void *from,
 214                                               unsigned long n);
 215
 216 static inline unsigned long copy_to_user(void __user *to, const void *from,
 217                                          unsigned long n)
 218 {
 219         if (access_ok(VERIFY_WRITE, to, n))
 220                 return __copy_user(to, from, n);
 221         return n;
 222 }
 223
 224 #define __copy_to_user(to, from, n) __copy_user(to, from, n)
 225 #define __copy_to_user_inatomic __copy_to_user
 226
 227 /*
 228  * Zero Userspace
 229  */
 230
 231 extern unsigned long __must_check __do_clear_user(void __user *to,
 232                                                   unsigned long n);
 233
 234 static inline unsigned long clear_user(void __user *to, unsigned long n)
 235 {
 236         if (access_ok(VERIFY_WRITE, to, n))
 237                 return __do_clear_user(to, n);
 238         return n;
 239 }
 240
 241 #define __clear_user(to, n)            __do_clear_user(to, n)
 242
 243 #endif /* _METAG_UACCESS_H */