arch/cris/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Authors:    Bjorn Wesen (bjornw@axis.com)
   4  *             Hans-Peter Nilsson (hp@axis.com)
   5  */
   6
   7 /* Asm:s have been tweaked (within the domain of correctness) to give
   8    satisfactory results for "gcc version 2.96 20000427 (experimental)".
   9
  10    Check regularly...
  11
  12    Register $r9 is chosen for temporaries, being a call-clobbered register
  13    first in line to be used (notably for local blocks), not colliding with
  14    parameter registers.  */
  15
  16 #ifndef _CRIS_UACCESS_H
  17 #define _CRIS_UACCESS_H
  18
  19 #include <asm/processor.h>
  20 #include <asm/page.h>
  21
  22 /*
  23  * The fs value determines whether argument validity checking should be
  24  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  25  * get_fs() == KERNEL_DS, checking is bypassed.
  26  *
  27  * For historical reasons, these macros are grossly misnamed.
  28  */
  29
  30 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  31
  32 /* addr_limit is the maximum accessible address for the task. we misuse
  33  * the KERNEL_DS and USER_DS values to both assign and compare the
  34  * addr_limit values through the equally misnamed get/set_fs macros.
  35  * (see above)
  36  */
  37
  38 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  39 #define USER_DS         MAKE_MM_SEG(TASK_SIZE)
  40
  41 #define get_ds()        (KERNEL_DS)
  42 #define get_fs()        (current_thread_info()->addr_limit)
  43 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  44
  45 #define segment_eq(a, b)        ((a).seg == (b).seg)
  46
  47 #define __kernel_ok (uaccess_kernel())
  48 #define __user_ok(addr, size) \
  49         (((size) <= TASK_SIZE) && ((addr) <= TASK_SIZE-(size)))
  50 #define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
  51 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr), (size))
  52
  53 #include <arch/uaccess.h>
  54 #include <asm/extable.h>
  55
  56 /*
  57  * These are the main single-value transfer routines.  They automatically
  58  * use the right size if we just have the right pointer type.
  59  *
  60  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  61  * and yet we don't want to do any pointers, because that is too much
  62  * of a performance impact. Thus we have a few rather ugly macros here,
  63  * and hide all the ugliness from the user.
  64  *
  65  * The "__xxx" versions of the user access functions are versions that
  66  * do not verify the address space, that must have been done previously
  67  * with a separate "access_ok()" call (this is used when we do multiple
  68  * accesses to the same area of user memory).
  69  *
  70  * As we use the same address space for kernel and user data on
  71  * CRIS, we can just do these as direct assignments.  (Of course, the
  72  * exception handling means that it's no longer "just"...)
  73  */
  74 #define get_user(x, ptr) \
  75         __get_user_check((x), (ptr), sizeof(*(ptr)))
  76 #define put_user(x, ptr) \
  77         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  78
  79 #define __get_user(x, ptr) \
  80         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  81 #define __put_user(x, ptr) \
  82         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  83
  84 extern long __put_user_bad(void);
  85
  86 #define __put_user_size(x, ptr, size, retval)                           \
  87 do {                                                                    \
  88         retval = 0;                                                     \
  89         switch (size) {                                                 \
  90         case 1:                                                         \
  91                 __put_user_asm(x, ptr, retval, "move.b");               \
  92                 break;                                                  \
  93         case 2:                                                         \
  94                 __put_user_asm(x, ptr, retval, "move.w");               \
  95                 break;                                                  \
  96         case 4:                                                         \
  97                 __put_user_asm(x, ptr, retval, "move.d");               \
  98                 break;                                                  \
  99         case 8:                                                         \
 100                 __put_user_asm_64(x, ptr, retval);                      \
 101                 break;                                                  \
 102         default:                                                        \
 103                 __put_user_bad();                                       \
 104         }                                                               \
 105 } while (0)
 106
 107 #define __get_user_size(x, ptr, size, retval)                           \
 108 do {                                                                    \
 109         retval = 0;                                                     \
 110         switch (size) {                                                 \
 111         case 1:                                                         \
 112                 __get_user_asm(x, ptr, retval, "move.b");               \
 113                 break;                                                  \
 114         case 2:                                                         \
 115                 __get_user_asm(x, ptr, retval, "move.w");               \
 116                 break;                                                  \
 117         case 4:                                                         \
 118                 __get_user_asm(x, ptr, retval, "move.d");               \
 119                 break;                                                  \
 120         case 8:                                                         \
 121                 __get_user_asm_64(x, ptr, retval);                      \
 122                 break;                                                  \
 123         default:                                                        \
 124                 (x) = __get_user_bad();                                 \
 125         }                                                               \
 126 } while (0)
 127
 128 #define __put_user_nocheck(x, ptr, size)                \
 129 ({                                                      \
 130         long __pu_err;                                  \
 131         __put_user_size((x), (ptr), (size), __pu_err);  \
 132         __pu_err;                                       \
 133 })
 134
 135 #define __put_user_check(x, ptr, size)                                  \
 136 ({                                                                      \
 137         long __pu_err = -EFAULT;                                        \
 138         __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 139         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 140                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 141         __pu_err;                                                       \
 142 })
 143
 144 struct __large_struct { unsigned long buf[100]; };
 145 #define __m(x) (*(struct __large_struct *)(x))
 146
 147
 148
 149 #define __get_user_nocheck(x, ptr, size)                        \
 150 ({                                                              \
 151         long __gu_err, __gu_val;                                \
 152         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 153         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 154         __gu_err;                                               \
 155 })
 156
 157 #define __get_user_check(x, ptr, size)                                  \
 158 ({                                                                      \
 159         long __gu_err = -EFAULT, __gu_val = 0;                          \
 160         const __typeof__(*(ptr)) *__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 long __get_user_bad(void);
 168
 169 /* More complex functions.  Most are inline, but some call functions that
 170    live in lib/usercopy.c  */
 171
 172 extern unsigned long __copy_user(void __user *to, const void *from, unsigned long n);
 173 extern unsigned long __copy_user_in(void *to, const void __user *from, unsigned long n);
 174 extern unsigned long __do_clear_user(void __user *to, unsigned long n);
 175
 176 static inline long
 177 strncpy_from_user(char *dst, const char __user *src, long count)
 178 {
 179         long res = -EFAULT;
 180
 181         if (access_ok(VERIFY_READ, src, 1))
 182                 res = __do_strncpy_from_user(dst, src, count);
 183         return res;
 184 }
 185
 186
 187 /* Note that these expand awfully if made into switch constructs, so
 188    don't do that.  */
 189
 190 static inline unsigned long
 191 __constant_copy_from_user(void *to, const void __user *from, unsigned long n)
 192 {
 193         unsigned long ret = 0;
 194
 195         if (n == 0)
 196                 ;
 197         else if (n == 1)
 198                 __asm_copy_from_user_1(to, from, ret);
 199         else if (n == 2)
 200                 __asm_copy_from_user_2(to, from, ret);
 201         else if (n == 3)
 202                 __asm_copy_from_user_3(to, from, ret);
 203         else if (n == 4)
 204                 __asm_copy_from_user_4(to, from, ret);
 205         else if (n == 5)
 206                 __asm_copy_from_user_5(to, from, ret);
 207         else if (n == 6)
 208                 __asm_copy_from_user_6(to, from, ret);
 209         else if (n == 7)
 210                 __asm_copy_from_user_7(to, from, ret);
 211         else if (n == 8)
 212                 __asm_copy_from_user_8(to, from, ret);
 213         else if (n == 9)
 214                 __asm_copy_from_user_9(to, from, ret);
 215         else if (n == 10)
 216                 __asm_copy_from_user_10(to, from, ret);
 217         else if (n == 11)
 218                 __asm_copy_from_user_11(to, from, ret);
 219         else if (n == 12)
 220                 __asm_copy_from_user_12(to, from, ret);
 221         else if (n == 13)
 222                 __asm_copy_from_user_13(to, from, ret);
 223         else if (n == 14)
 224                 __asm_copy_from_user_14(to, from, ret);
 225         else if (n == 15)
 226                 __asm_copy_from_user_15(to, from, ret);
 227         else if (n == 16)
 228                 __asm_copy_from_user_16(to, from, ret);
 229         else if (n == 20)
 230                 __asm_copy_from_user_20(to, from, ret);
 231         else if (n == 24)
 232                 __asm_copy_from_user_24(to, from, ret);
 233         else
 234                 ret = __copy_user_in(to, from, n);
 235
 236         return ret;
 237 }
 238
 239 /* Ditto, don't make a switch out of this.  */
 240
 241 static inline unsigned long
 242 __constant_copy_to_user(void __user *to, const void *from, unsigned long n)
 243 {
 244         unsigned long ret = 0;
 245
 246         if (n == 0)
 247                 ;
 248         else if (n == 1)
 249                 __asm_copy_to_user_1(to, from, ret);
 250         else if (n == 2)
 251                 __asm_copy_to_user_2(to, from, ret);
 252         else if (n == 3)
 253                 __asm_copy_to_user_3(to, from, ret);
 254         else if (n == 4)
 255                 __asm_copy_to_user_4(to, from, ret);
 256         else if (n == 5)
 257                 __asm_copy_to_user_5(to, from, ret);
 258         else if (n == 6)
 259                 __asm_copy_to_user_6(to, from, ret);
 260         else if (n == 7)
 261                 __asm_copy_to_user_7(to, from, ret);
 262         else if (n == 8)
 263                 __asm_copy_to_user_8(to, from, ret);
 264         else if (n == 9)
 265                 __asm_copy_to_user_9(to, from, ret);
 266         else if (n == 10)
 267                 __asm_copy_to_user_10(to, from, ret);
 268         else if (n == 11)
 269                 __asm_copy_to_user_11(to, from, ret);
 270         else if (n == 12)
 271                 __asm_copy_to_user_12(to, from, ret);
 272         else if (n == 13)
 273                 __asm_copy_to_user_13(to, from, ret);
 274         else if (n == 14)
 275                 __asm_copy_to_user_14(to, from, ret);
 276         else if (n == 15)
 277                 __asm_copy_to_user_15(to, from, ret);
 278         else if (n == 16)
 279                 __asm_copy_to_user_16(to, from, ret);
 280         else if (n == 20)
 281                 __asm_copy_to_user_20(to, from, ret);
 282         else if (n == 24)
 283                 __asm_copy_to_user_24(to, from, ret);
 284         else
 285                 ret = __copy_user(to, from, n);
 286
 287         return ret;
 288 }
 289
 290 /* No switch, please.  */
 291
 292 static inline unsigned long
 293 __constant_clear_user(void __user *to, unsigned long n)
 294 {
 295         unsigned long ret = 0;
 296
 297         if (n == 0)
 298                 ;
 299         else if (n == 1)
 300                 __asm_clear_1(to, ret);
 301         else if (n == 2)
 302                 __asm_clear_2(to, ret);
 303         else if (n == 3)
 304                 __asm_clear_3(to, ret);
 305         else if (n == 4)
 306                 __asm_clear_4(to, ret);
 307         else if (n == 8)
 308                 __asm_clear_8(to, ret);
 309         else if (n == 12)
 310                 __asm_clear_12(to, ret);
 311         else if (n == 16)
 312                 __asm_clear_16(to, ret);
 313         else if (n == 20)
 314                 __asm_clear_20(to, ret);
 315         else if (n == 24)
 316                 __asm_clear_24(to, ret);
 317         else
 318                 ret = __do_clear_user(to, n);
 319
 320         return ret;
 321 }
 322
 323
 324 static inline size_t clear_user(void __user *to, size_t n)
 325 {
 326         if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
 327                 return n;
 328         if (__builtin_constant_p(n))
 329                 return __constant_clear_user(to, n);
 330         else
 331                 return __do_clear_user(to, n);
 332 }
 333
 334 static inline unsigned long
 335 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 336 {
 337         if (__builtin_constant_p(n))
 338                 return __constant_copy_from_user(to, from, n);
 339         else
 340                 return __copy_user_in(to, from, n);
 341 }
 342
 343 static inline unsigned long
 344 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 345 {
 346         if (__builtin_constant_p(n))
 347                 return __constant_copy_to_user(to, from, n);
 348         else
 349                 return __copy_user(to, from, n);
 350 }
 351
 352 #define INLINE_COPY_FROM_USER
 353 #define INLINE_COPY_TO_USER
 354
 355 static inline unsigned long
 356 __clear_user(void __user *to, unsigned long n)
 357 {
 358         return __do_clear_user(to, n);
 359 }
 360
 361 #endif  /* _CRIS_UACCESS_H */