arch/nds32/include/asm/uaccess.h

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4 #ifndef _ASMANDES_UACCESS_H
   5 #define _ASMANDES_UACCESS_H
   6
   7 /*
   8  * User space memory access functions
   9  */
  10 #include <linux/sched.h>
  11 #include <asm/errno.h>
  12 #include <asm/memory.h>
  13 #include <asm/types.h>
  14 #include <linux/mm.h>
  15
  16 #define VERIFY_READ     0
  17 #define VERIFY_WRITE    1
  18
  19 #define __asmeq(x, y)  ".ifnc " x "," y " ; .err ; .endif\n\t"
  20
  21 /*
  22  * The exception table consists of pairs of addresses: the first is the
  23  * address of an instruction that is allowed to fault, and the second is
  24  * the address at which the program should continue.  No registers are
  25  * modified, so it is entirely up to the continuation code to figure out
  26  * what to do.
  27  *
  28  * All the routines below use bits of fixup code that are out of line
  29  * with the main instruction path.  This means when everything is well,
  30  * we don't even have to jump over them.  Further, they do not intrude
  31  * on our cache or tlb entries.
  32  */
  33
  34 struct exception_table_entry {
  35         unsigned long insn, fixup;
  36 };
  37
  38 extern int fixup_exception(struct pt_regs *regs);
  39
  40 #define KERNEL_DS       ((mm_segment_t) { ~0UL })
  41 #define USER_DS         ((mm_segment_t) {TASK_SIZE - 1})
  42
  43 #define get_ds()        (KERNEL_DS)
  44 #define get_fs()        (current_thread_info()->addr_limit)
  45 #define user_addr_max   get_fs
  46
  47 static inline void set_fs(mm_segment_t fs)
  48 {
  49         current_thread_info()->addr_limit = fs;
  50 }
  51
  52 #define segment_eq(a, b)        ((a) == (b))
  53
  54 #define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs() -size))
  55
  56 #define access_ok(type, addr, size)     \
  57         __range_ok((unsigned long)addr, (unsigned long)size)
  58 /*
  59  * Single-value transfer routines.  They automatically use the right
  60  * size if we just have the right pointer type.  Note that the functions
  61  * which read from user space (*get_*) need to take care not to leak
  62  * kernel data even if the calling code is buggy and fails to check
  63  * the return value.  This means zeroing out the destination variable
  64  * or buffer on error.  Normally this is done out of line by the
  65  * fixup code, but there are a few places where it intrudes on the
  66  * main code path.  When we only write to user space, there is no
  67  * problem.
  68  *
  69  * The "__xxx" versions of the user access functions do not verify the
  70  * address space - it must have been done previously with a separate
  71  * "access_ok()" call.
  72  *
  73  * The "xxx_error" versions set the third argument to EFAULT if an
  74  * error occurs, and leave it unchanged on success.  Note that these
  75  * versions are void (ie, don't return a value as such).
  76  */
  77
  78 #define get_user        __get_user                                      \
  79
  80 #define __get_user(x, ptr)                                              \
  81 ({                                                                      \
  82         long __gu_err = 0;                                              \
  83         __get_user_check((x), (ptr), __gu_err);                         \
  84         __gu_err;                                                       \
  85 })
  86
  87 #define __get_user_error(x, ptr, err)                                   \
  88 ({                                                                      \
  89         __get_user_check((x), (ptr), (err));                            \
  90         (void)0;                                                        \
  91 })
  92
  93 #define __get_user_check(x, ptr, err)                                   \
  94 ({                                                                      \
  95         const __typeof__(*(ptr)) __user *__p = (ptr);                   \
  96         might_fault();                                                  \
  97         if (access_ok(VERIFY_READ, __p, sizeof(*__p))) {                \
  98                 __get_user_err((x), __p, (err));                        \
  99         } else {                                                        \
 100                 (x) = 0; (err) = -EFAULT;                               \
 101         }                                                               \
 102 })
 103
 104 #define __get_user_err(x, ptr, err)                                     \
 105 do {                                                                    \
 106         unsigned long __gu_val;                                         \
 107         __chk_user_ptr(ptr);                                            \
 108         switch (sizeof(*(ptr))) {                                       \
 109         case 1:                                                         \
 110                 __get_user_asm("lbi", __gu_val, (ptr), (err));          \
 111                 break;                                                  \
 112         case 2:                                                         \
 113                 __get_user_asm("lhi", __gu_val, (ptr), (err));          \
 114                 break;                                                  \
 115         case 4:                                                         \
 116                 __get_user_asm("lwi", __gu_val, (ptr), (err));          \
 117                 break;                                                  \
 118         case 8:                                                         \
 119                 __get_user_asm_dword(__gu_val, (ptr), (err));           \
 120                 break;                                                  \
 121         default:                                                        \
 122                 BUILD_BUG();                                            \
 123                 break;                                                  \
 124         }                                                               \
 125         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 126 } while (0)
 127
 128 #define __get_user_asm(inst, x, addr, err)                              \
 129         __asm__ __volatile__ (                                          \
 130                 "1:     "inst"  %1,[%2]\n"                              \
 131                 "2:\n"                                                  \
 132                 "       .section .fixup,\"ax\"\n"                       \
 133                 "       .align  2\n"                                    \
 134                 "3:     move %0, %3\n"                                  \
 135                 "       move %1, #0\n"                                  \
 136                 "       b       2b\n"                                   \
 137                 "       .previous\n"                                    \
 138                 "       .section __ex_table,\"a\"\n"                    \
 139                 "       .align  3\n"                                    \
 140                 "       .long   1b, 3b\n"                               \
 141                 "       .previous"                                      \
 142                 : "+r" (err), "=&r" (x)                                 \
 143                 : "r" (addr), "i" (-EFAULT)                             \
 144                 : "cc")
 145
 146 #ifdef __NDS32_EB__
 147 #define __gu_reg_oper0 "%H1"
 148 #define __gu_reg_oper1 "%L1"
 149 #else
 150 #define __gu_reg_oper0 "%L1"
 151 #define __gu_reg_oper1 "%H1"
 152 #endif
 153
 154 #define __get_user_asm_dword(x, addr, err)                              \
 155         __asm__ __volatile__ (                                          \
 156                 "\n1:\tlwi " __gu_reg_oper0 ",[%2]\n"                   \
 157                 "\n2:\tlwi " __gu_reg_oper1 ",[%2+4]\n"                 \
 158                 "3:\n"                                                  \
 159                 "       .section .fixup,\"ax\"\n"                       \
 160                 "       .align  2\n"                                    \
 161                 "4:     move    %0, %3\n"                               \
 162                 "       b       3b\n"                                   \
 163                 "       .previous\n"                                    \
 164                 "       .section __ex_table,\"a\"\n"                    \
 165                 "       .align  3\n"                                    \
 166                 "       .long   1b, 4b\n"                               \
 167                 "       .long   2b, 4b\n"                               \
 168                 "       .previous"                                      \
 169                 : "+r"(err), "=&r"(x)                                   \
 170                 : "r"(addr), "i"(-EFAULT)                               \
 171                 : "cc")
 172
 173 #define put_user        __put_user                                      \
 174
 175 #define __put_user(x, ptr)                                              \
 176 ({                                                                      \
 177         long __pu_err = 0;                                              \
 178         __put_user_err((x), (ptr), __pu_err);                           \
 179         __pu_err;                                                       \
 180 })
 181
 182 #define __put_user_error(x, ptr, err)                                   \
 183 ({                                                                      \
 184         __put_user_err((x), (ptr), (err));                              \
 185         (void)0;                                                        \
 186 })
 187
 188 #define __put_user_check(x, ptr, err)                                   \
 189 ({                                                                      \
 190         __typeof__(*(ptr)) __user *__p = (ptr);                         \
 191         might_fault();                                                  \
 192         if (access_ok(VERIFY_WRITE, __p, sizeof(*__p))) {               \
 193                 __put_user_err((x), __p, (err));                        \
 194         } else  {                                                       \
 195                 (err) = -EFAULT;                                        \
 196         }                                                               \
 197 })
 198
 199 #define __put_user_err(x, ptr, err)                                     \
 200 do {                                                                    \
 201         __typeof__(*(ptr)) __pu_val = (x);                              \
 202         __chk_user_ptr(ptr);                                            \
 203         switch (sizeof(*(ptr))) {                                       \
 204         case 1:                                                         \
 205                 __put_user_asm("sbi", __pu_val, (ptr), (err));          \
 206                 break;                                                  \
 207         case 2:                                                         \
 208                 __put_user_asm("shi", __pu_val, (ptr), (err));          \
 209                 break;                                                  \
 210         case 4:                                                         \
 211                 __put_user_asm("swi", __pu_val, (ptr), (err));          \
 212                 break;                                                  \
 213         case 8:                                                         \
 214                 __put_user_asm_dword(__pu_val, (ptr), (err));           \
 215                 break;                                                  \
 216         default:                                                        \
 217                 BUILD_BUG();                                            \
 218                 break;                                                  \
 219         }                                                               \
 220 } while (0)
 221
 222 #define __put_user_asm(inst, x, addr, err)                              \
 223         __asm__ __volatile__ (                                          \
 224                 "1:     "inst"  %1,[%2]\n"                              \
 225                 "2:\n"                                                  \
 226                 "       .section .fixup,\"ax\"\n"                       \
 227                 "       .align  2\n"                                    \
 228                 "3:     move    %0, %3\n"                               \
 229                 "       b       2b\n"                                   \
 230                 "       .previous\n"                                    \
 231                 "       .section __ex_table,\"a\"\n"                    \
 232                 "       .align  3\n"                                    \
 233                 "       .long   1b, 3b\n"                               \
 234                 "       .previous"                                      \
 235                 : "+r" (err)                                            \
 236                 : "r" (x), "r" (addr), "i" (-EFAULT)                    \
 237                 : "cc")
 238
 239 #ifdef __NDS32_EB__
 240 #define __pu_reg_oper0 "%H2"
 241 #define __pu_reg_oper1 "%L2"
 242 #else
 243 #define __pu_reg_oper0 "%L2"
 244 #define __pu_reg_oper1 "%H2"
 245 #endif
 246
 247 #define __put_user_asm_dword(x, addr, err)                              \
 248         __asm__ __volatile__ (                                          \
 249                 "\n1:\tswi " __pu_reg_oper0 ",[%1]\n"                   \
 250                 "\n2:\tswi " __pu_reg_oper1 ",[%1+4]\n"                 \
 251                 "3:\n"                                                  \
 252                 "       .section .fixup,\"ax\"\n"                       \
 253                 "       .align  2\n"                                    \
 254                 "4:     move    %0, %3\n"                               \
 255                 "       b       3b\n"                                   \
 256                 "       .previous\n"                                    \
 257                 "       .section __ex_table,\"a\"\n"                    \
 258                 "       .align  3\n"                                    \
 259                 "       .long   1b, 4b\n"                               \
 260                 "       .long   2b, 4b\n"                               \
 261                 "       .previous"                                      \
 262                 : "+r"(err)                                             \
 263                 : "r"(addr), "r"(x), "i"(-EFAULT)                       \
 264                 : "cc")
 265
 266 extern unsigned long __arch_clear_user(void __user * addr, unsigned long n);
 267 extern long strncpy_from_user(char *dest, const char __user * src, long count);
 268 extern __must_check long strlen_user(const char __user * str);
 269 extern __must_check long strnlen_user(const char __user * str, long n);
 270 extern unsigned long __arch_copy_from_user(void *to, const void __user * from,
 271                                            unsigned long n);
 272 extern unsigned long __arch_copy_to_user(void __user * to, const void *from,
 273                                          unsigned long n);
 274
 275 #define raw_copy_from_user __arch_copy_from_user
 276 #define raw_copy_to_user __arch_copy_to_user
 277
 278 #define INLINE_COPY_FROM_USER
 279 #define INLINE_COPY_TO_USER
 280 static inline unsigned long clear_user(void __user * to, unsigned long n)
 281 {
 282         if (access_ok(VERIFY_WRITE, to, n))
 283                 n = __arch_clear_user(to, n);
 284         return n;
 285 }
 286
 287 static inline unsigned long __clear_user(void __user * to, unsigned long n)
 288 {
 289         return __arch_clear_user(to, n);
 290 }
 291
 292 #endif /* _ASMNDS32_UACCESS_H */