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