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