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 #define VERIFY_READ     0
  10 #define VERIFY_WRITE    1
  11
  12 /*
  13  * The fs value determines whether argument validity checking should be
  14  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  15  * get_fs() == KERNEL_DS, checking is bypassed.
  16  *
  17  * For historical reasons, these macros are grossly misnamed.
  18  */
  19
  20 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  21
  22 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  23 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
  24
  25 #define get_ds()        (KERNEL_DS)
  26 #define get_fs()        (current_thread_info()->addr_limit)
  27 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  28
  29 #define segment_eq(a, b)        ((a).seg == (b).seg)
  30
  31 static inline int __access_ok(unsigned long addr, unsigned long size)
  32 {
  33         /*
  34          * Allow access to the user mapped memory area, but not the system area
  35          * before it. The check extends to the top of the address space when
  36          * kernel access is allowed (there's no real reason to user copy to the
  37          * system area in any case).
  38          */
  39         if (likely(addr >= META_MEMORY_BASE && addr < get_fs().seg &&
  40                    size <= get_fs().seg - addr))
  41                 return true;
  42         /*
  43          * Explicitly allow NULL pointers here. Parts of the kernel such
  44          * as readv/writev use access_ok to validate pointers, but want
  45          * to allow NULL pointers for various reasons. NULL pointers are
  46          * safe to allow through because the first page is not mappable on
  47          * Meta.
  48          */
  49         if (!addr)
  50                 return true;
  51         /* Allow access to core code memory area... */
  52         if (addr >= LINCORE_CODE_BASE && addr <= LINCORE_CODE_LIMIT &&
  53             size <= LINCORE_CODE_LIMIT + 1 - addr)
  54                 return true;
  55         /* ... but no other areas. */
  56         return false;
  57 }
  58
  59 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),  \
  60                                                 (unsigned long)(size))
  61
  62 static inline int verify_area(int type, const void *addr, unsigned long size)
  63 {
  64         return access_ok(type, addr, size) ? 0 : -EFAULT;
  65 }
  66
  67 /*
  68  * The exception table consists of pairs of addresses: the first is the
  69  * address of an instruction that is allowed to fault, and the second is
  70  * the address at which the program should continue.  No registers are
  71  * modified, so it is entirely up to the continuation code to figure out
  72  * what to do.
  73  *
  74  * All the routines below use bits of fixup code that are out of line
  75  * with the main instruction path.  This means when everything is well,
  76  * we don't even have to jump over them.  Further, they do not intrude
  77  * on our cache or tlb entries.
  78  */
  79 struct exception_table_entry {
  80         unsigned long insn, fixup;
  81 };
  82
  83 extern int fixup_exception(struct pt_regs *regs);
  84
  85 /*
  86  * These are the main single-value transfer routines.  They automatically
  87  * use the right size if we just have the right pointer type.
  88  */
  89
  90 #define put_user(x, ptr) \
  91         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  92 #define __put_user(x, ptr) \
  93         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  94
  95 extern void __put_user_bad(void);
  96
  97 #define __put_user_nocheck(x, ptr, size)                \
  98 ({                                                      \
  99         long __pu_err;                                  \
 100         __put_user_size((x), (ptr), (size), __pu_err);  \
 101         __pu_err;                                       \
 102 })
 103
 104 #define __put_user_check(x, ptr, size)                          \
 105 ({                                                              \
 106         long __pu_err = -EFAULT;                                \
 107         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 108         if (access_ok(VERIFY_WRITE, __pu_addr, size))           \
 109                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 110         __pu_err;                                               \
 111 })
 112
 113 extern long __put_user_asm_b(unsigned int x, void __user *addr);
 114 extern long __put_user_asm_w(unsigned int x, void __user *addr);
 115 extern long __put_user_asm_d(unsigned int x, void __user *addr);
 116 extern long __put_user_asm_l(unsigned long long x, void __user *addr);
 117
 118 #define __put_user_size(x, ptr, size, retval)                           \
 119 do {                                                                    \
 120         retval = 0;                                                     \
 121         switch (size) {                                                 \
 122         case 1:                                                         \
 123                 retval = __put_user_asm_b((__force unsigned int)x, ptr);\
 124                 break;                                                  \
 125         case 2:                                                         \
 126                 retval = __put_user_asm_w((__force unsigned int)x, ptr);\
 127                 break;                                                  \
 128         case 4:                                                         \
 129                 retval = __put_user_asm_d((__force unsigned int)x, ptr);\
 130                 break;                                                  \
 131         case 8:                                                         \
 132                 retval = __put_user_asm_l((__force unsigned long long)x,\
 133                                           ptr);                         \
 134                 break;                                                  \
 135         default:                                                        \
 136                 __put_user_bad();                                       \
 137         }                                                               \
 138 } while (0)
 139
 140 #define get_user(x, ptr) \
 141         __get_user_check((x), (ptr), sizeof(*(ptr)))
 142 #define __get_user(x, ptr) \
 143         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 144
 145 extern long __get_user_bad(void);
 146
 147 #define __get_user_nocheck(x, ptr, size)                        \
 148 ({                                                              \
 149         long __gu_err;                                          \
 150         long long __gu_val;                                     \
 151         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 152         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 153         __gu_err;                                               \
 154 })
 155
 156 #define __get_user_check(x, ptr, size)                                  \
 157 ({                                                                      \
 158         long __gu_err = -EFAULT;                                        \
 159         long long __gu_val = 0;                                         \
 160         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 161         if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 162                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 163         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 164         __gu_err;                                                       \
 165 })
 166
 167 extern unsigned char __get_user_asm_b(const void __user *addr, long *err);
 168 extern unsigned short __get_user_asm_w(const void __user *addr, long *err);
 169 extern unsigned int __get_user_asm_d(const void __user *addr, long *err);
 170 extern unsigned long long __get_user_asm_l(const void __user *addr, long *err);
 171
 172 #define __get_user_size(x, ptr, size, retval)                   \
 173 do {                                                            \
 174         retval = 0;                                             \
 175         switch (size) {                                         \
 176         case 1:                                                 \
 177                 x = __get_user_asm_b(ptr, &retval); break;      \
 178         case 2:                                                 \
 179                 x = __get_user_asm_w(ptr, &retval); break;      \
 180         case 4:                                                 \
 181                 x = __get_user_asm_d(ptr, &retval); break;      \
 182         case 8:                                                 \
 183                 x = __get_user_asm_l(ptr, &retval); break;      \
 184         default:                                                \
 185                 (x) = __get_user_bad();                         \
 186         }                                                       \
 187 } while (0)
 188
 189 /*
 190  * Copy a null terminated string from userspace.
 191  *
 192  * Must return:
 193  * -EFAULT              for an exception
 194  * count                if we hit the buffer limit
 195  * bytes copied         if we hit a null byte
 196  * (without the null byte)
 197  */
 198
 199 extern long __must_check __strncpy_from_user(char *dst, const char __user *src,
 200                                              long count);
 201
 202 static inline long
 203 strncpy_from_user(char *dst, const char __user *src, long count)
 204 {
 205         if (!access_ok(VERIFY_READ, src, 1))
 206                 return -EFAULT;
 207         return __strncpy_from_user(dst, src, count);
 208 }
 209 /*
 210  * Return the size of a string (including the ending 0)
 211  *
 212  * Return 0 on exception, a value greater than N if too long
 213  */
 214 extern long __must_check strnlen_user(const char __user *src, long count);
 215
 216 #define strlen_user(str) strnlen_user(str, 32767)
 217
 218 extern unsigned long raw_copy_from_user(void *to, const void __user *from,
 219                                         unsigned long n);
 220
 221 static inline unsigned long
 222 copy_from_user(void *to, const void __user *from, unsigned long n)
 223 {
 224         unsigned long res = n;
 225         if (likely(access_ok(VERIFY_READ, from, n)))
 226                 res = raw_copy_from_user(to, from, n);
 227         if (unlikely(res))
 228                 memset(to + (n - res), 0, res);
 229         return res;
 230 }
 231
 232 #define __copy_from_user(to, from, n) raw_copy_from_user(to, from, n)
 233 #define __copy_from_user_inatomic __copy_from_user
 234
 235 extern unsigned long __must_check __copy_user(void __user *to,
 236                                               const void *from,
 237                                               unsigned long n);
 238
 239 static inline unsigned long copy_to_user(void __user *to, const void *from,
 240                                          unsigned long n)
 241 {
 242         if (access_ok(VERIFY_WRITE, to, n))
 243                 return __copy_user(to, from, n);
 244         return n;
 245 }
 246
 247 #define __copy_to_user(to, from, n) __copy_user(to, from, n)
 248 #define __copy_to_user_inatomic __copy_to_user
 249
 250 /*
 251  * Zero Userspace
 252  */
 253
 254 extern unsigned long __must_check __do_clear_user(void __user *to,
 255                                                   unsigned long n);
 256
 257 static inline unsigned long clear_user(void __user *to, unsigned long n)
 258 {
 259         if (access_ok(VERIFY_WRITE, to, n))
 260                 return __do_clear_user(to, n);
 261         return n;
 262 }
 263
 264 #define __clear_user(to, n)            __do_clear_user(to, n)
 265
 266 #endif /* _METAG_UACCESS_H */