arch/score/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __SCORE_UACCESS_H
   3 #define __SCORE_UACCESS_H
   4
   5 #include <linux/kernel.h>
   6 #include <asm/extable.h>
   7
   8 #define get_ds()                (KERNEL_DS)
   9 #define get_fs()                (current_thread_info()->addr_limit)
  10 #define segment_eq(a, b)        ((a).seg == (b).seg)
  11
  12 /*
  13  * Is a address valid? This does a straighforward calculation rather
  14  * than tests.
  15  *
  16  * Address valid if:
  17  *  - "addr" doesn't have any high-bits set
  18  *  - AND "size" doesn't have any high-bits set
  19  *  - AND "addr+size" doesn't have any high-bits set
  20  *  - OR we are in kernel mode.
  21  *
  22  * __ua_size() is a trick to avoid runtime checking of positive constant
  23  * sizes; for those we already know at compile time that the size is ok.
  24  */
  25 #define __ua_size(size)                                                 \
  26         ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
  27
  28 /*
  29  * access_ok: - Checks if a user space pointer is valid
  30  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  31  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  32  *        to write to a block, it is always safe to read from it.
  33  * @addr: User space pointer to start of block to check
  34  * @size: Size of block to check
  35  *
  36  * Context: User context only. This function may sleep if pagefaults are
  37  *          enabled.
  38  *
  39  * Checks if a pointer to a block of memory in user space is valid.
  40  *
  41  * Returns true (nonzero) if the memory block may be valid, false (zero)
  42  * if it is definitely invalid.
  43  *
  44  * Note that, depending on architecture, this function probably just
  45  * checks that the pointer is in the user space range - after calling
  46  * this function, memory access functions may still return -EFAULT.
  47  */
  48
  49 #define __access_ok(addr, size)                                 \
  50         (((long)((get_fs().seg) &                               \
  51                  ((addr) | ((addr) + (size)) |                  \
  52                   __ua_size(size)))) == 0)
  53
  54 #define access_ok(type, addr, size)                             \
  55         likely(__access_ok((unsigned long)(addr), (size)))
  56
  57 /*
  58  * put_user: - Write a simple value into user space.
  59  * @x:   Value to copy to user space.
  60  * @ptr: Destination address, in user space.
  61  *
  62  * Context: User context only. This function may sleep if pagefaults are
  63  *          enabled.
  64  *
  65  * This macro copies a single simple value from kernel space to user
  66  * space.  It supports simple types like char and int, but not larger
  67  * data types like structures or arrays.
  68  *
  69  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
  70  * to the result of dereferencing @ptr.
  71  *
  72  * Returns zero on success, or -EFAULT on error.
  73  */
  74 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
  75
  76 /*
  77  * get_user: - Get a simple variable from user space.
  78  * @x:   Variable to store result.
  79  * @ptr: Source address, in user space.
  80  *
  81  * Context: User context only. This function may sleep if pagefaults are
  82  *          enabled.
  83  *
  84  * This macro copies a single simple variable from user space to kernel
  85  * space.  It supports simple types like char and int, but not larger
  86  * data types like structures or arrays.
  87  *
  88  * @ptr must have pointer-to-simple-variable type, and the result of
  89  * dereferencing @ptr must be assignable to @x without a cast.
  90  *
  91  * Returns zero on success, or -EFAULT on error.
  92  * On error, the variable @x is set to zero.
  93  */
  94 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
  95
  96 /*
  97  * __put_user: - Write a simple value into user space, with less checking.
  98  * @x:   Value to copy to user space.
  99  * @ptr: Destination address, in user space.
 100  *
 101  * Context: User context only. This function may sleep if pagefaults are
 102  *          enabled.
 103  *
 104  * This macro copies a single simple value from kernel space to user
 105  * space.  It supports simple types like char and int, but not larger
 106  * data types like structures or arrays.
 107  *
 108  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 109  * to the result of dereferencing @ptr.
 110  *
 111  * Caller must check the pointer with access_ok() before calling this
 112  * function.
 113  *
 114  * Returns zero on success, or -EFAULT on error.
 115  */
 116 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 117
 118 /*
 119  * __get_user: - Get a simple variable from user space, with less checking.
 120  * @x:   Variable to store result.
 121  * @ptr: Source address, in user space.
 122  *
 123  * Context: User context only. This function may sleep if pagefaults are
 124  *          enabled.
 125  *
 126  * This macro copies a single simple variable from user space to kernel
 127  * space.  It supports simple types like char and int, but not larger
 128  * data types like structures or arrays.
 129  *
 130  * @ptr must have pointer-to-simple-variable type, and the result of
 131  * dereferencing @ptr must be assignable to @x without a cast.
 132  *
 133  * Caller must check the pointer with access_ok() before calling this
 134  * function.
 135  *
 136  * Returns zero on success, or -EFAULT on error.
 137  * On error, the variable @x is set to zero.
 138  */
 139 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 140
 141 struct __large_struct { unsigned long buf[100]; };
 142 #define __m(x) (*(struct __large_struct __user *)(x))
 143
 144 /*
 145  * Yuck.  We need two variants, one for 64bit operation and one
 146  * for 32 bit mode and old iron.
 147  */
 148 extern void __get_user_unknown(void);
 149
 150 #define __get_user_common(val, size, ptr)                               \
 151 do {                                                                    \
 152         switch (size) {                                                 \
 153         case 1:                                                         \
 154                 __get_user_asm(val, "lb", ptr);                         \
 155                 break;                                                  \
 156         case 2:                                                         \
 157                 __get_user_asm(val, "lh", ptr);                         \
 158                  break;                                                 \
 159         case 4:                                                         \
 160                 __get_user_asm(val, "lw", ptr);                         \
 161                  break;                                                 \
 162         case 8:                                                         \
 163                 if (__copy_from_user((void *)&val, ptr, 8) == 0)        \
 164                         __gu_err = 0;                                   \
 165                 else                                                    \
 166                         __gu_err = -EFAULT;                             \
 167                 break;                                                  \
 168         default:                                                        \
 169                 __get_user_unknown();                                   \
 170                 break;                                                  \
 171         }                                                               \
 172 } while (0)
 173
 174 #define __get_user_nocheck(x, ptr, size)                                \
 175 ({                                                                      \
 176         long __gu_err = 0;                                              \
 177         __get_user_common((x), size, ptr);                              \
 178         __gu_err;                                                       \
 179 })
 180
 181 #define __get_user_check(x, ptr, size)                                  \
 182 ({                                                                      \
 183         long __gu_err = -EFAULT;                                        \
 184         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);              \
 185                                                                         \
 186         if (likely(access_ok(VERIFY_READ, __gu_ptr, size)))             \
 187                 __get_user_common((x), size, __gu_ptr);                 \
 188         else                                                            \
 189                 (x) = 0;                                                \
 190                                                                         \
 191         __gu_err;                                                       \
 192 })
 193
 194 #define __get_user_asm(val, insn, addr)                                 \
 195 {                                                                       \
 196         long __gu_tmp;                                                  \
 197                                                                         \
 198         __asm__ __volatile__(                                           \
 199                 "1:" insn " %1, %3\n"                                   \
 200                 "2:\n"                                                  \
 201                 ".section .fixup,\"ax\"\n"                              \
 202                 "3:li   %0, %4\n"                                       \
 203                 "li     %1, 0\n"                                        \
 204                 "j      2b\n"                                           \
 205                 ".previous\n"                                           \
 206                 ".section __ex_table,\"a\"\n"                           \
 207                 ".word  1b, 3b\n"                                       \
 208                 ".previous\n"                                           \
 209                 : "=r" (__gu_err), "=r" (__gu_tmp)                      \
 210                 : "0" (0), "o" (__m(addr)), "i" (-EFAULT));             \
 211                                                                         \
 212                 (val) = (__typeof__(*(addr))) __gu_tmp;                 \
 213 }
 214
 215 /*
 216  * Yuck.  We need two variants, one for 64bit operation and one
 217  * for 32 bit mode and old iron.
 218  */
 219 #define __put_user_nocheck(val, ptr, size)                              \
 220 ({                                                                      \
 221         __typeof__(*(ptr)) __pu_val;                                    \
 222         long __pu_err = 0;                                              \
 223                                                                         \
 224         __pu_val = (val);                                               \
 225         switch (size) {                                                 \
 226         case 1:                                                         \
 227                 __put_user_asm("sb", ptr);                              \
 228                 break;                                                  \
 229         case 2:                                                         \
 230                 __put_user_asm("sh", ptr);                              \
 231                 break;                                                  \
 232         case 4:                                                         \
 233                 __put_user_asm("sw", ptr);                              \
 234                 break;                                                  \
 235         case 8:                                                         \
 236                 if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0)   \
 237                         __pu_err = 0;                                   \
 238                 else                                                    \
 239                         __pu_err = -EFAULT;                             \
 240                 break;                                                  \
 241         default:                                                        \
 242                  __put_user_unknown();                                  \
 243                  break;                                                 \
 244         }                                                               \
 245         __pu_err;                                                       \
 246 })
 247
 248
 249 #define __put_user_check(val, ptr, size)                                \
 250 ({                                                                      \
 251         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 252         __typeof__(*(ptr)) __pu_val = (val);                            \
 253         long __pu_err = -EFAULT;                                        \
 254                                                                         \
 255         if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) {         \
 256                 switch (size) {                                         \
 257                 case 1:                                                 \
 258                         __put_user_asm("sb", __pu_addr);                \
 259                         break;                                          \
 260                 case 2:                                                 \
 261                         __put_user_asm("sh", __pu_addr);                \
 262                         break;                                          \
 263                 case 4:                                                 \
 264                         __put_user_asm("sw", __pu_addr);                \
 265                         break;                                          \
 266                 case 8:                                                 \
 267                         if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\
 268                                 __pu_err = 0;                           \
 269                         else                                            \
 270                                 __pu_err = -EFAULT;                     \
 271                         break;                                          \
 272                 default:                                                \
 273                         __put_user_unknown();                           \
 274                         break;                                          \
 275                 }                                                       \
 276         }                                                               \
 277         __pu_err;                                                       \
 278 })
 279
 280 #define __put_user_asm(insn, ptr)                                       \
 281         __asm__ __volatile__(                                           \
 282                 "1:" insn " %2, %3\n"                                   \
 283                 "2:\n"                                                  \
 284                 ".section .fixup,\"ax\"\n"                              \
 285                 "3:li %0, %4\n"                                         \
 286                 "j 2b\n"                                                \
 287                 ".previous\n"                                           \
 288                 ".section __ex_table,\"a\"\n"                           \
 289                 ".word 1b, 3b\n"                                        \
 290                 ".previous\n"                                           \
 291                 : "=r" (__pu_err)                                       \
 292                 : "0" (0), "r" (__pu_val), "o" (__m(ptr)),              \
 293                   "i" (-EFAULT));
 294
 295 extern void __put_user_unknown(void);
 296 extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);
 297
 298 static inline unsigned long
 299 raw_copy_from_user(void *to, const void __user *from, unsigned long len)
 300 {
 301         return __copy_tofrom_user(to, (__force const void *)from, len);
 302 }
 303
 304 static inline unsigned long
 305 raw_copy_to_user(void __user *to, const void *from, unsigned long len)
 306 {
 307         return __copy_tofrom_user((__force void *)to, from, len);
 308 }
 309
 310 #define INLINE_COPY_FROM_USER
 311 #define INLINE_COPY_TO_USER
 312
 313 /*
 314  * __clear_user: - Zero a block of memory in user space, with less checking.
 315  * @to:   Destination address, in user space.
 316  * @n:    Number of bytes to zero.
 317  *
 318  * Zero a block of memory in user space.  Caller must check
 319  * the specified block with access_ok() before calling this function.
 320  *
 321  * Returns number of bytes that could not be cleared.
 322  * On success, this will be zero.
 323  */
 324 extern unsigned long __clear_user(void __user *src, unsigned long size);
 325
 326 static inline unsigned long clear_user(char *src, unsigned long size)
 327 {
 328         if (access_ok(VERIFY_WRITE, src, size))
 329                 return __clear_user(src, size);
 330
 331         return -EFAULT;
 332 }
 333 /*
 334  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 335  * @dst:   Destination address, in kernel space.  This buffer must be at
 336  *         least @count bytes long.
 337  * @src:   Source address, in user space.
 338  * @count: Maximum number of bytes to copy, including the trailing NUL.
 339  *
 340  * Copies a NUL-terminated string from userspace to kernel space.
 341  * Caller must check the specified block with access_ok() before calling
 342  * this function.
 343  *
 344  * On success, returns the length of the string (not including the trailing
 345  * NUL).
 346  *
 347  * If access to userspace fails, returns -EFAULT (some data may have been
 348  * copied).
 349  *
 350  * If @count is smaller than the length of the string, copies @count bytes
 351  * and returns @count.
 352  */
 353 extern int __strncpy_from_user(char *dst, const char *src, long len);
 354
 355 static inline int strncpy_from_user(char *dst, const char *src, long len)
 356 {
 357         if (access_ok(VERIFY_READ, src, 1))
 358                 return __strncpy_from_user(dst, src, len);
 359
 360         return -EFAULT;
 361 }
 362
 363 extern int __strnlen_user(const char *str, long len);
 364 static inline long strnlen_user(const char __user *str, long len)
 365 {
 366         if (!access_ok(VERIFY_READ, str, 0))
 367                 return 0;
 368         else
 369                 return __strnlen_user(str, len);
 370 }
 371
 372 #endif /* __SCORE_UACCESS_H */
 373