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 #define get_ds()        (KERNEL_DS)
  46
  47 #define USER_DS         (TASK_SIZE)
  48 #define get_fs()        (current_thread_info()->addr_limit)
  49 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  50
  51 #define segment_eq(a, b)        ((a) == (b))
  52
  53 /* Ensure that the range from addr to addr+size is all within the process'
  54  * address space
  55  */
  56 #define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))
  57
  58 /* Ensure that addr is below task's addr_limit */
  59 #define __addr_ok(addr) ((unsigned long) addr < get_fs())
  60
  61 #define access_ok(type, addr, size) \
  62         __range_ok((unsigned long)addr, (unsigned long)size)
  63
  64 /*
  65  * These are the main single-value transfer routines.  They automatically
  66  * use the right size if we just have the right pointer type.
  67  *
  68  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  69  * and yet we don't want to do any pointers, because that is too much
  70  * of a performance impact. Thus we have a few rather ugly macros here,
  71  * and hide all the uglyness from the user.
  72  *
  73  * The "__xxx" versions of the user access functions are versions that
  74  * do not verify the address space, that must have been done previously
  75  * with a separate "access_ok()" call (this is used when we do multiple
  76  * accesses to the same area of user memory).
  77  *
  78  * As we use the same address space for kernel and user data on the
  79  * PowerPC, we can just do these as direct assignments.  (Of course, the
  80  * exception handling means that it's no longer "just"...)
  81  */
  82 #define get_user(x, ptr) \
  83         __get_user_check((x), (ptr), sizeof(*(ptr)))
  84 #define put_user(x, ptr) \
  85         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  86
  87 #define __get_user(x, ptr) \
  88         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  89 #define __put_user(x, ptr) \
  90         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  91
  92 extern long __put_user_bad(void);
  93
  94 #define __put_user_nocheck(x, ptr, size)                \
  95 ({                                                      \
  96         long __pu_err;                                  \
  97         __put_user_size((x), (ptr), (size), __pu_err);  \
  98         __pu_err;                                       \
  99 })
 100
 101 #define __put_user_check(x, ptr, size)                                  \
 102 ({                                                                      \
 103         long __pu_err = -EFAULT;                                        \
 104         __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 105         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 106                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 107         __pu_err;                                                       \
 108 })
 109
 110 #define __put_user_size(x, ptr, size, retval)                           \
 111 do {                                                                    \
 112         retval = 0;                                                     \
 113         switch (size) {                                                 \
 114         case 1: __put_user_asm(x, ptr, retval, "l.sb"); break;          \
 115         case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;          \
 116         case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;          \
 117         case 8: __put_user_asm2(x, ptr, retval); break;                 \
 118         default: __put_user_bad();                                      \
 119         }                                                               \
 120 } while (0)
 121
 122 struct __large_struct {
 123         unsigned long buf[100];
 124 };
 125 #define __m(x) (*(struct __large_struct *)(x))
 126
 127 /*
 128  * We don't tell gcc that we are accessing memory, but this is OK
 129  * because we do not write to any memory gcc knows about, so there
 130  * are no aliasing issues.
 131  */
 132 #define __put_user_asm(x, addr, err, op)                        \
 133         __asm__ __volatile__(                                   \
 134                 "1:     "op" 0(%2),%1\n"                        \
 135                 "2:\n"                                          \
 136                 ".section .fixup,\"ax\"\n"                      \
 137                 "3:     l.addi %0,r0,%3\n"                      \
 138                 "       l.j 2b\n"                               \
 139                 "       l.nop\n"                                \
 140                 ".previous\n"                                   \
 141                 ".section __ex_table,\"a\"\n"                   \
 142                 "       .align 2\n"                             \
 143                 "       .long 1b,3b\n"                          \
 144                 ".previous"                                     \
 145                 : "=r"(err)                                     \
 146                 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 147
 148 #define __put_user_asm2(x, addr, err)                           \
 149         __asm__ __volatile__(                                   \
 150                 "1:     l.sw 0(%2),%1\n"                        \
 151                 "2:     l.sw 4(%2),%H1\n"                       \
 152                 "3:\n"                                          \
 153                 ".section .fixup,\"ax\"\n"                      \
 154                 "4:     l.addi %0,r0,%3\n"                      \
 155                 "       l.j 3b\n"                               \
 156                 "       l.nop\n"                                \
 157                 ".previous\n"                                   \
 158                 ".section __ex_table,\"a\"\n"                   \
 159                 "       .align 2\n"                             \
 160                 "       .long 1b,4b\n"                          \
 161                 "       .long 2b,4b\n"                          \
 162                 ".previous"                                     \
 163                 : "=r"(err)                                     \
 164                 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 165
 166 #define __get_user_nocheck(x, ptr, size)                        \
 167 ({                                                              \
 168         long __gu_err, __gu_val;                                \
 169         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 170         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 171         __gu_err;                                               \
 172 })
 173
 174 #define __get_user_check(x, ptr, size)                                  \
 175 ({                                                                      \
 176         long __gu_err = -EFAULT, __gu_val = 0;                          \
 177         const __typeof__(*(ptr)) * __gu_addr = (ptr);                   \
 178         if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 179                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 180         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 181         __gu_err;                                                       \
 182 })
 183
 184 extern long __get_user_bad(void);
 185
 186 #define __get_user_size(x, ptr, size, retval)                           \
 187 do {                                                                    \
 188         retval = 0;                                                     \
 189         switch (size) {                                                 \
 190         case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break;         \
 191         case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;         \
 192         case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;         \
 193         case 8: __get_user_asm2(x, ptr, retval); break;                 \
 194         default: (x) = __get_user_bad();                                \
 195         }                                                               \
 196 } while (0)
 197
 198 #define __get_user_asm(x, addr, err, op)                \
 199         __asm__ __volatile__(                           \
 200                 "1:     "op" %1,0(%2)\n"                \
 201                 "2:\n"                                  \
 202                 ".section .fixup,\"ax\"\n"              \
 203                 "3:     l.addi %0,r0,%3\n"              \
 204                 "       l.addi %1,r0,0\n"               \
 205                 "       l.j 2b\n"                       \
 206                 "       l.nop\n"                        \
 207                 ".previous\n"                           \
 208                 ".section __ex_table,\"a\"\n"           \
 209                 "       .align 2\n"                     \
 210                 "       .long 1b,3b\n"                  \
 211                 ".previous"                             \
 212                 : "=r"(err), "=r"(x)                    \
 213                 : "r"(addr), "i"(-EFAULT), "0"(err))
 214
 215 #define __get_user_asm2(x, addr, err)                   \
 216         __asm__ __volatile__(                           \
 217                 "1:     l.lwz %1,0(%2)\n"               \
 218                 "2:     l.lwz %H1,4(%2)\n"              \
 219                 "3:\n"                                  \
 220                 ".section .fixup,\"ax\"\n"              \
 221                 "4:     l.addi %0,r0,%3\n"              \
 222                 "       l.addi %1,r0,0\n"               \
 223                 "       l.addi %H1,r0,0\n"              \
 224                 "       l.j 3b\n"                       \
 225                 "       l.nop\n"                        \
 226                 ".previous\n"                           \
 227                 ".section __ex_table,\"a\"\n"           \
 228                 "       .align 2\n"                     \
 229                 "       .long 1b,4b\n"                  \
 230                 "       .long 2b,4b\n"                  \
 231                 ".previous"                             \
 232                 : "=r"(err), "=&r"(x)                   \
 233                 : "r"(addr), "i"(-EFAULT), "0"(err))
 234
 235 /* more complex routines */
 236
 237 extern unsigned long __must_check
 238 __copy_tofrom_user(void *to, const void *from, unsigned long size);
 239 static inline unsigned long
 240 raw_copy_from_user(void *to, const void __user *from, unsigned long size)
 241 {
 242         return __copy_tofrom_user(to, (__force const void *)from, size);
 243 }
 244 static inline unsigned long
 245 raw_copy_to_user(void *to, const void __user *from, unsigned long size)
 246 {
 247         return __copy_tofrom_user((__force void *)to, from, size);
 248 }
 249 #define INLINE_COPY_FROM_USER
 250 #define INLINE_COPY_TO_USER
 251
 252 extern unsigned long __clear_user(void *addr, unsigned long size);
 253
 254 static inline __must_check unsigned long
 255 clear_user(void *addr, unsigned long size)
 256 {
 257         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 258                 size = __clear_user(addr, size);
 259         return size;
 260 }
 261
 262 #define user_addr_max() \
 263         (uaccess_kernel() ? ~0UL : TASK_SIZE)
 264
 265 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 266
 267 extern __must_check long strnlen_user(const char __user *str, long n);
 268
 269 #endif /* __ASM_OPENRISC_UACCESS_H */