arch/microblaze/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
   4  * Copyright (C) 2008-2009 PetaLogix
   5  * Copyright (C) 2006 Atmark Techno, Inc.
   6  */
   7
   8 #ifndef _ASM_MICROBLAZE_UACCESS_H
   9 #define _ASM_MICROBLAZE_UACCESS_H
  10
  11 #include <linux/kernel.h>
  12
  13 #include <asm/mmu.h>
  14 #include <asm/page.h>
  15 #include <linux/pgtable.h>
  16 #include <asm/extable.h>
  17 #include <linux/string.h>
  18
  19 /*
  20  * On Microblaze the fs value is actually the top of the corresponding
  21  * address space.
  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  * For non-MMU arch like Microblaze, KERNEL_DS and USER_DS is equal.
  30  */
  31 # define MAKE_MM_SEG(s)       ((mm_segment_t) { (s) })
  32
  33 #  define KERNEL_DS     MAKE_MM_SEG(0xFFFFFFFF)
  34 #  define USER_DS       MAKE_MM_SEG(TASK_SIZE - 1)
  35
  36 # define get_fs()       (current_thread_info()->addr_limit)
  37 # define set_fs(val)    (current_thread_info()->addr_limit = (val))
  38
  39 # define uaccess_kernel()       (get_fs().seg == KERNEL_DS.seg)
  40
  41 static inline int access_ok(const void __user *addr, unsigned long size)
  42 {
  43         if (!size)
  44                 goto ok;
  45
  46         if ((get_fs().seg < ((unsigned long)addr)) ||
  47                         (get_fs().seg < ((unsigned long)addr + size - 1))) {
  48                 pr_devel("ACCESS fail at 0x%08x (size 0x%x), seg 0x%08x\n",
  49                         (__force u32)addr, (u32)size,
  50                         (u32)get_fs().seg);
  51                 return 0;
  52         }
  53 ok:
  54         pr_devel("ACCESS OK at 0x%08x (size 0x%x), seg 0x%08x\n",
  55                         (__force u32)addr, (u32)size,
  56                         (u32)get_fs().seg);
  57         return 1;
  58 }
  59
  60 # define __FIXUP_SECTION        ".section .fixup,\"ax\"\n"
  61 # define __EX_TABLE_SECTION     ".section __ex_table,\"a\"\n"
  62
  63 extern unsigned long __copy_tofrom_user(void __user *to,
  64                 const void __user *from, unsigned long size);
  65
  66 /* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
  67 static inline unsigned long __must_check __clear_user(void __user *to,
  68                                                         unsigned long n)
  69 {
  70         /* normal memset with two words to __ex_table */
  71         __asm__ __volatile__ (                          \
  72                         "1:     sb      r0, %1, r0;"    \
  73                         "       addik   %0, %0, -1;"    \
  74                         "       bneid   %0, 1b;"        \
  75                         "       addik   %1, %1, 1;"     \
  76                         "2:                     "       \
  77                         __EX_TABLE_SECTION              \
  78                         ".word  1b,2b;"                 \
  79                         ".previous;"                    \
  80                 : "=r"(n), "=r"(to)                     \
  81                 : "0"(n), "1"(to)
  82         );
  83         return n;
  84 }
  85
  86 static inline unsigned long __must_check clear_user(void __user *to,
  87                                                         unsigned long n)
  88 {
  89         might_fault();
  90         if (unlikely(!access_ok(to, n)))
  91                 return n;
  92
  93         return __clear_user(to, n);
  94 }
  95
  96 /* put_user and get_user macros */
  97 extern long __user_bad(void);
  98
  99 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 100 ({                                                              \
 101         __asm__ __volatile__ (                                  \
 102                         "1:"    insn    " %1, %2, r0;"          \
 103                         "       addk    %0, r0, r0;"            \
 104                         "2:                     "               \
 105                         __FIXUP_SECTION                         \
 106                         "3:     brid    2b;"                    \
 107                         "       addik   %0, r0, %3;"            \
 108                         ".previous;"                            \
 109                         __EX_TABLE_SECTION                      \
 110                         ".word  1b,3b;"                         \
 111                         ".previous;"                            \
 112                 : "=&r"(__gu_err), "=r"(__gu_val)               \
 113                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
 114         );                                                      \
 115 })
 116
 117 /**
 118  * get_user: - Get a simple variable from user space.
 119  * @x:   Variable to store result.
 120  * @ptr: Source address, in user space.
 121  *
 122  * Context: User context only. This function may sleep if pagefaults are
 123  *          enabled.
 124  *
 125  * This macro copies a single simple variable from user space to kernel
 126  * space.  It supports simple types like char and int, but not larger
 127  * data types like structures or arrays.
 128  *
 129  * @ptr must have pointer-to-simple-variable type, and the result of
 130  * dereferencing @ptr must be assignable to @x without a cast.
 131  *
 132  * Returns zero on success, or -EFAULT on error.
 133  * On error, the variable @x is set to zero.
 134  */
 135 #define get_user(x, ptr) ({                             \
 136         const typeof(*(ptr)) __user *__gu_ptr = (ptr);  \
 137         access_ok(__gu_ptr, sizeof(*__gu_ptr)) ?        \
 138                 __get_user(x, __gu_ptr) : -EFAULT;      \
 139 })
 140
 141 #define __get_user(x, ptr)                                              \
 142 ({                                                                      \
 143         unsigned long __gu_val = 0;                                     \
 144         long __gu_err;                                                  \
 145         switch (sizeof(*(ptr))) {                                       \
 146         case 1:                                                         \
 147                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 148                 break;                                                  \
 149         case 2:                                                         \
 150                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 151                 break;                                                  \
 152         case 4:                                                         \
 153                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 154                 break;                                                  \
 155         case 8:                                                         \
 156                 __gu_err = __copy_from_user(&__gu_val, ptr, 8);         \
 157                 if (__gu_err)                                           \
 158                         __gu_err = -EFAULT;                             \
 159                 break;                                                  \
 160         default:                                                        \
 161                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 162         }                                                               \
 163         x = (__force __typeof__(*(ptr))) __gu_val;                      \
 164         __gu_err;                                                       \
 165 })
 166
 167
 168 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 169 ({                                                              \
 170         __asm__ __volatile__ (                                  \
 171                         "1:"    insn    " %1, %2, r0;"          \
 172                         "       addk    %0, r0, r0;"            \
 173                         "2:                     "               \
 174                         __FIXUP_SECTION                         \
 175                         "3:     brid    2b;"                    \
 176                         "       addik   %0, r0, %3;"            \
 177                         ".previous;"                            \
 178                         __EX_TABLE_SECTION                      \
 179                         ".word  1b,3b;"                         \
 180                         ".previous;"                            \
 181                 : "=&r"(__gu_err)                               \
 182                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 183         );                                                      \
 184 })
 185
 186 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 187 ({                                                              \
 188         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 189                         "1:     swi     %0, %2, 0;"             \
 190                         "       lwi     %0, %1, 4;"             \
 191                         "2:     swi     %0, %2, 4;"             \
 192                         "       addk    %0, r0, r0;"            \
 193                         "3:                     "               \
 194                         __FIXUP_SECTION                         \
 195                         "4:     brid    3b;"                    \
 196                         "       addik   %0, r0, %3;"            \
 197                         ".previous;"                            \
 198                         __EX_TABLE_SECTION                      \
 199                         ".word  1b,4b,2b,4b;"                   \
 200                         ".previous;"                            \
 201                 : "=&r"(__gu_err)                               \
 202                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 203                 );                                              \
 204 })
 205
 206 /**
 207  * put_user: - Write a simple value into user space.
 208  * @x:   Value to copy to user space.
 209  * @ptr: Destination address, in user space.
 210  *
 211  * Context: User context only. This function may sleep if pagefaults are
 212  *          enabled.
 213  *
 214  * This macro copies a single simple value from kernel space to user
 215  * space.  It supports simple types like char and int, but not larger
 216  * data types like structures or arrays.
 217  *
 218  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 219  * to the result of dereferencing @ptr.
 220  *
 221  * Returns zero on success, or -EFAULT on error.
 222  */
 223 #define put_user(x, ptr)                                                \
 224         __put_user_check((x), (ptr), sizeof(*(ptr)))
 225
 226 #define __put_user_check(x, ptr, size)                                  \
 227 ({                                                                      \
 228         typeof(*(ptr)) volatile __pu_val = x;                           \
 229         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
 230         int __pu_err = 0;                                               \
 231                                                                         \
 232         if (access_ok(__pu_addr, size)) {                       \
 233                 switch (size) {                                         \
 234                 case 1:                                                 \
 235                         __put_user_asm("sb", __pu_addr, __pu_val,       \
 236                                        __pu_err);                       \
 237                         break;                                          \
 238                 case 2:                                                 \
 239                         __put_user_asm("sh", __pu_addr, __pu_val,       \
 240                                        __pu_err);                       \
 241                         break;                                          \
 242                 case 4:                                                 \
 243                         __put_user_asm("sw", __pu_addr, __pu_val,       \
 244                                        __pu_err);                       \
 245                         break;                                          \
 246                 case 8:                                                 \
 247                         __put_user_asm_8(__pu_addr, __pu_val, __pu_err);\
 248                         break;                                          \
 249                 default:                                                \
 250                         __pu_err = __user_bad();                        \
 251                         break;                                          \
 252                 }                                                       \
 253         } else {                                                        \
 254                 __pu_err = -EFAULT;                                     \
 255         }                                                               \
 256         __pu_err;                                                       \
 257 })
 258
 259 #define __put_user(x, ptr)                                              \
 260 ({                                                                      \
 261         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 262         long __gu_err = 0;                                              \
 263         switch (sizeof(__gu_val)) {                                     \
 264         case 1:                                                         \
 265                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 266                 break;                                                  \
 267         case 2:                                                         \
 268                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 269                 break;                                                  \
 270         case 4:                                                         \
 271                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 272                 break;                                                  \
 273         case 8:                                                         \
 274                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 275                 break;                                                  \
 276         default:                                                        \
 277                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
 278         }                                                               \
 279         __gu_err;                                                       \
 280 })
 281
 282 static inline unsigned long
 283 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 284 {
 285         return __copy_tofrom_user((__force void __user *)to, from, n);
 286 }
 287
 288 static inline unsigned long
 289 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 290 {
 291         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 292 }
 293 #define INLINE_COPY_FROM_USER
 294 #define INLINE_COPY_TO_USER
 295
 296 /*
 297  * Copy a null terminated string from userspace.
 298  */
 299 extern int __strncpy_user(char *to, const char __user *from, int len);
 300
 301 static inline long
 302 strncpy_from_user(char *dst, const char __user *src, long count)
 303 {
 304         if (!access_ok(src, 1))
 305                 return -EFAULT;
 306         return __strncpy_user(dst, src, count);
 307 }
 308
 309 /*
 310  * Return the size of a string (including the ending 0)
 311  *
 312  * Return 0 on exception, a value greater than N if too long
 313  */
 314 extern int __strnlen_user(const char __user *sstr, int len);
 315
 316 static inline long strnlen_user(const char __user *src, long n)
 317 {
 318         if (!access_ok(src, 1))
 319                 return 0;
 320         return __strnlen_user(src, n);
 321 }
 322
 323 #endif /* _ASM_MICROBLAZE_UACCESS_H */