arch/openrisc/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * OpenRISC Linux
   4  *
   5  * Linux architectural port borrowing liberally from similar works of
   6  * others.  All original copyrights apply as per the original source
   7  * declaration.
   8  *
   9  * OpenRISC implementation:
  10  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  11  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12  * et al.
  13  */
  14
  15 #ifndef __ASM_OPENRISC_UACCESS_H
  16 #define __ASM_OPENRISC_UACCESS_H
  17
  18 /*
  19  * User space memory access functions
  20  */
  21 #include <linux/prefetch.h>
  22 #include <linux/string.h>
  23 #include <asm/page.h>
  24 #include <asm/extable.h>
  25
  26 /*
  27  * The fs value determines whether argument validity checking should be
  28  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  29  * get_fs() == KERNEL_DS, checking is bypassed.
  30  *
  31  * For historical reasons, these macros are grossly misnamed.
  32  */
  33
  34 /* addr_limit is the maximum accessible address for the task. we misuse
  35  * the KERNEL_DS and USER_DS values to both assign and compare the
  36  * addr_limit values through the equally misnamed get/set_fs macros.
  37  * (see above)
  38  */
  39
  40 #define KERNEL_DS       (~0UL)
  41
  42 #define USER_DS         (TASK_SIZE)
  43 #define get_fs()        (current_thread_info()->addr_limit)
  44 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  45
  46 #define uaccess_kernel()        (get_fs() == KERNEL_DS)
  47
  48 /* Ensure that the range from addr to addr+size is all within the process'
  49  * address space
  50  */
  51 static inline int __range_ok(unsigned long addr, unsigned long size)
  52 {
  53         const mm_segment_t fs = get_fs();
  54
  55         return size <= fs && addr <= (fs - size);
  56 }
  57
  58 #define access_ok(addr, size)                                           \
  59 ({                                                                      \
  60         __chk_user_ptr(addr);                                           \
  61         __range_ok((unsigned long)(addr), (size));                      \
  62 })
  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)) __user *__pu_addr = (ptr);                   \
 105         if (access_ok(__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;                                          \
 169         __get_user_size((x), (ptr), (size), __gu_err);          \
 170         __gu_err;                                               \
 171 })
 172
 173 #define __get_user_check(x, ptr, size)                                  \
 174 ({                                                                      \
 175         long __gu_err = -EFAULT;                                        \
 176         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 177         if (access_ok(__gu_addr, size))                                 \
 178                 __get_user_size((x), __gu_addr, (size), __gu_err);      \
 179         else                                                            \
 180                 (x) = (__typeof__(*(ptr))) 0;                           \
 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) = (__typeof__(*(ptr)))__get_user_bad();            \
 195         }                                                               \
 196 } while (0)
 197
 198 #define __get_user_asm(x, addr, err, op)                \
 199 {                                                       \
 200         unsigned long __gu_tmp;                         \
 201         __asm__ __volatile__(                           \
 202                 "1:     "op" %1,0(%2)\n"                \
 203                 "2:\n"                                  \
 204                 ".section .fixup,\"ax\"\n"              \
 205                 "3:     l.addi %0,r0,%3\n"              \
 206                 "       l.addi %1,r0,0\n"               \
 207                 "       l.j 2b\n"                       \
 208                 "       l.nop\n"                        \
 209                 ".previous\n"                           \
 210                 ".section __ex_table,\"a\"\n"           \
 211                 "       .align 2\n"                     \
 212                 "       .long 1b,3b\n"                  \
 213                 ".previous"                             \
 214                 : "=r"(err), "=r"(__gu_tmp)             \
 215                 : "r"(addr), "i"(-EFAULT), "0"(err));   \
 216         (x) = (__typeof__(*(addr)))__gu_tmp;            \
 217 }
 218
 219 #define __get_user_asm2(x, addr, err)                   \
 220 {                                                       \
 221         unsigned long long __gu_tmp;                    \
 222         __asm__ __volatile__(                           \
 223                 "1:     l.lwz %1,0(%2)\n"               \
 224                 "2:     l.lwz %H1,4(%2)\n"              \
 225                 "3:\n"                                  \
 226                 ".section .fixup,\"ax\"\n"              \
 227                 "4:     l.addi %0,r0,%3\n"              \
 228                 "       l.addi %1,r0,0\n"               \
 229                 "       l.addi %H1,r0,0\n"              \
 230                 "       l.j 3b\n"                       \
 231                 "       l.nop\n"                        \
 232                 ".previous\n"                           \
 233                 ".section __ex_table,\"a\"\n"           \
 234                 "       .align 2\n"                     \
 235                 "       .long 1b,4b\n"                  \
 236                 "       .long 2b,4b\n"                  \
 237                 ".previous"                             \
 238                 : "=r"(err), "=&r"(__gu_tmp)            \
 239                 : "r"(addr), "i"(-EFAULT), "0"(err));   \
 240         (x) = (__typeof__(*(addr)))(                    \
 241                 (__typeof__((x)-(x)))__gu_tmp);         \
 242 }
 243
 244 /* more complex routines */
 245
 246 extern unsigned long __must_check
 247 __copy_tofrom_user(void *to, const void *from, unsigned long size);
 248 static inline unsigned long
 249 raw_copy_from_user(void *to, const void __user *from, unsigned long size)
 250 {
 251         return __copy_tofrom_user(to, (__force const void *)from, size);
 252 }
 253 static inline unsigned long
 254 raw_copy_to_user(void __user *to, const void *from, unsigned long size)
 255 {
 256         return __copy_tofrom_user((__force void *)to, from, size);
 257 }
 258 #define INLINE_COPY_FROM_USER
 259 #define INLINE_COPY_TO_USER
 260
 261 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 262
 263 static inline __must_check unsigned long
 264 clear_user(void __user *addr, unsigned long size)
 265 {
 266         if (likely(access_ok(addr, size)))
 267                 size = __clear_user(addr, size);
 268         return size;
 269 }
 270
 271 #define user_addr_max() \
 272         (uaccess_kernel() ? ~0UL : TASK_SIZE)
 273
 274 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 275
 276 extern __must_check long strnlen_user(const char __user *str, long n);
 277
 278 #endif /* __ASM_OPENRISC_UACCESS_H */