arch/openrisc/include/asm/uaccess.h

   1 /*
   2  * OpenRISC Linux
   3  *
   4  * Linux architectural port borrowing liberally from similar works of
   5  * others.  All original copyrights apply as per the original source
   6  * declaration.
   7  *
   8  * OpenRISC implementation:
   9  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  10  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  11  * et al.
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  */
  18
  19 #ifndef __ASM_OPENRISC_UACCESS_H
  20 #define __ASM_OPENRISC_UACCESS_H
  21
  22 /*
  23  * User space memory access functions
  24  */
  25 #include <linux/prefetch.h>
  26 #include <linux/string.h>
  27 #include <asm/page.h>
  28 #include <asm/extable.h>
  29
  30 /*
  31  * The fs value determines whether argument validity checking should be
  32  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  33  * get_fs() == KERNEL_DS, checking is bypassed.
  34  *
  35  * For historical reasons, these macros are grossly misnamed.
  36  */
  37
  38 /* addr_limit is the maximum accessible address for the task. we misuse
  39  * the KERNEL_DS and USER_DS values to both assign and compare the
  40  * addr_limit values through the equally misnamed get/set_fs macros.
  41  * (see above)
  42  */
  43
  44 #define KERNEL_DS       (~0UL)
  45
  46 #define USER_DS         (TASK_SIZE)
  47 #define get_fs()        (current_thread_info()->addr_limit)
  48 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  49
  50 #define segment_eq(a, b)        ((a) == (b))
  51
  52 /* Ensure that the range from addr to addr+size is all within the process'
  53  * address space
  54  */
  55 #define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))
  56
  57 /* Ensure that addr is below task's addr_limit */
  58 #define __addr_ok(addr) ((unsigned long) addr < get_fs())
  59
  60 #define access_ok(addr, size)                                           \
  61 ({                                                                      \
  62         unsigned long __ao_addr = (unsigned long)(addr);                \
  63         unsigned long __ao_size = (unsigned long)(size);                \
  64         __range_ok(__ao_addr, __ao_size);                               \
  65 })
  66
  67 /*
  68  * These are the main single-value transfer routines.  They automatically
  69  * use the right size if we just have the right pointer type.
  70  *
  71  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  72  * and yet we don't want to do any pointers, because that is too much
  73  * of a performance impact. Thus we have a few rather ugly macros here,
  74  * and hide all the uglyness from the user.
  75  *
  76  * The "__xxx" versions of the user access functions are versions that
  77  * do not verify the address space, that must have been done previously
  78  * with a separate "access_ok()" call (this is used when we do multiple
  79  * accesses to the same area of user memory).
  80  *
  81  * As we use the same address space for kernel and user data on the
  82  * PowerPC, we can just do these as direct assignments.  (Of course, the
  83  * exception handling means that it's no longer "just"...)
  84  */
  85 #define get_user(x, ptr) \
  86         __get_user_check((x), (ptr), sizeof(*(ptr)))
  87 #define put_user(x, ptr) \
  88         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  89
  90 #define __get_user(x, ptr) \
  91         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  92 #define __put_user(x, ptr) \
  93         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  94
  95 extern long __put_user_bad(void);
  96
  97 #define __put_user_nocheck(x, ptr, size)                \
  98 ({                                                      \
  99         long __pu_err;                                  \
 100         __put_user_size((x), (ptr), (size), __pu_err);  \
 101         __pu_err;                                       \
 102 })
 103
 104 #define __put_user_check(x, ptr, size)                                  \
 105 ({                                                                      \
 106         long __pu_err = -EFAULT;                                        \
 107         __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 108         if (access_ok(__pu_addr, size))                 \
 109                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 110         __pu_err;                                                       \
 111 })
 112
 113 #define __put_user_size(x, ptr, size, retval)                           \
 114 do {                                                                    \
 115         retval = 0;                                                     \
 116         switch (size) {                                                 \
 117         case 1: __put_user_asm(x, ptr, retval, "l.sb"); break;          \
 118         case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;          \
 119         case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;          \
 120         case 8: __put_user_asm2(x, ptr, retval); break;                 \
 121         default: __put_user_bad();                                      \
 122         }                                                               \
 123 } while (0)
 124
 125 struct __large_struct {
 126         unsigned long buf[100];
 127 };
 128 #define __m(x) (*(struct __large_struct *)(x))
 129
 130 /*
 131  * We don't tell gcc that we are accessing memory, but this is OK
 132  * because we do not write to any memory gcc knows about, so there
 133  * are no aliasing issues.
 134  */
 135 #define __put_user_asm(x, addr, err, op)                        \
 136         __asm__ __volatile__(                                   \
 137                 "1:     "op" 0(%2),%1\n"                        \
 138                 "2:\n"                                          \
 139                 ".section .fixup,\"ax\"\n"                      \
 140                 "3:     l.addi %0,r0,%3\n"                      \
 141                 "       l.j 2b\n"                               \
 142                 "       l.nop\n"                                \
 143                 ".previous\n"                                   \
 144                 ".section __ex_table,\"a\"\n"                   \
 145                 "       .align 2\n"                             \
 146                 "       .long 1b,3b\n"                          \
 147                 ".previous"                                     \
 148                 : "=r"(err)                                     \
 149                 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 150
 151 #define __put_user_asm2(x, addr, err)                           \
 152         __asm__ __volatile__(                                   \
 153                 "1:     l.sw 0(%2),%1\n"                        \
 154                 "2:     l.sw 4(%2),%H1\n"                       \
 155                 "3:\n"                                          \
 156                 ".section .fixup,\"ax\"\n"                      \
 157                 "4:     l.addi %0,r0,%3\n"                      \
 158                 "       l.j 3b\n"                               \
 159                 "       l.nop\n"                                \
 160                 ".previous\n"                                   \
 161                 ".section __ex_table,\"a\"\n"                   \
 162                 "       .align 2\n"                             \
 163                 "       .long 1b,4b\n"                          \
 164                 "       .long 2b,4b\n"                          \
 165                 ".previous"                                     \
 166                 : "=r"(err)                                     \
 167                 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 168
 169 #define __get_user_nocheck(x, ptr, size)                        \
 170 ({                                                              \
 171         long __gu_err, __gu_val;                                \
 172         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 173         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 174         __gu_err;                                               \
 175 })
 176
 177 #define __get_user_check(x, ptr, size)                                  \
 178 ({                                                                      \
 179         long __gu_err = -EFAULT, __gu_val = 0;                          \
 180         const __typeof__(*(ptr)) * __gu_addr = (ptr);                   \
 181         if (access_ok(__gu_addr, size))                 \
 182                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 183         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 184         __gu_err;                                                       \
 185 })
 186
 187 extern long __get_user_bad(void);
 188
 189 #define __get_user_size(x, ptr, size, retval)                           \
 190 do {                                                                    \
 191         retval = 0;                                                     \
 192         switch (size) {                                                 \
 193         case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break;         \
 194         case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;         \
 195         case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;         \
 196         case 8: __get_user_asm2(x, ptr, retval); break;                 \
 197         default: (x) = __get_user_bad();                                \
 198         }                                                               \
 199 } while (0)
 200
 201 #define __get_user_asm(x, addr, err, op)                \
 202         __asm__ __volatile__(                           \
 203                 "1:     "op" %1,0(%2)\n"                \
 204                 "2:\n"                                  \
 205                 ".section .fixup,\"ax\"\n"              \
 206                 "3:     l.addi %0,r0,%3\n"              \
 207                 "       l.addi %1,r0,0\n"               \
 208                 "       l.j 2b\n"                       \
 209                 "       l.nop\n"                        \
 210                 ".previous\n"                           \
 211                 ".section __ex_table,\"a\"\n"           \
 212                 "       .align 2\n"                     \
 213                 "       .long 1b,3b\n"                  \
 214                 ".previous"                             \
 215                 : "=r"(err), "=r"(x)                    \
 216                 : "r"(addr), "i"(-EFAULT), "0"(err))
 217
 218 #define __get_user_asm2(x, addr, err)                   \
 219         __asm__ __volatile__(                           \
 220                 "1:     l.lwz %1,0(%2)\n"               \
 221                 "2:     l.lwz %H1,4(%2)\n"              \
 222                 "3:\n"                                  \
 223                 ".section .fixup,\"ax\"\n"              \
 224                 "4:     l.addi %0,r0,%3\n"              \
 225                 "       l.addi %1,r0,0\n"               \
 226                 "       l.addi %H1,r0,0\n"              \
 227                 "       l.j 3b\n"                       \
 228                 "       l.nop\n"                        \
 229                 ".previous\n"                           \
 230                 ".section __ex_table,\"a\"\n"           \
 231                 "       .align 2\n"                     \
 232                 "       .long 1b,4b\n"                  \
 233                 "       .long 2b,4b\n"                  \
 234                 ".previous"                             \
 235                 : "=r"(err), "=&r"(x)                   \
 236                 : "r"(addr), "i"(-EFAULT), "0"(err))
 237
 238 /* more complex routines */
 239
 240 extern unsigned long __must_check
 241 __copy_tofrom_user(void *to, const void *from, unsigned long size);
 242 static inline unsigned long
 243 raw_copy_from_user(void *to, const void __user *from, unsigned long size)
 244 {
 245         return __copy_tofrom_user(to, (__force const void *)from, size);
 246 }
 247 static inline unsigned long
 248 raw_copy_to_user(void *to, const void __user *from, unsigned long size)
 249 {
 250         return __copy_tofrom_user((__force void *)to, from, size);
 251 }
 252 #define INLINE_COPY_FROM_USER
 253 #define INLINE_COPY_TO_USER
 254
 255 extern unsigned long __clear_user(void *addr, unsigned long size);
 256
 257 static inline __must_check unsigned long
 258 clear_user(void *addr, unsigned long size)
 259 {
 260         if (likely(access_ok(addr, size)))
 261                 size = __clear_user(addr, size);
 262         return size;
 263 }
 264
 265 #define user_addr_max() \
 266         (uaccess_kernel() ? ~0UL : TASK_SIZE)
 267
 268 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 269
 270 extern __must_check long strnlen_user(const char __user *str, long n);
 271
 272 #endif /* __ASM_OPENRISC_UACCESS_H */