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 #include <asm-generic/access_ok.h>
  26
  27 /*
  28  * These are the main single-value transfer routines.  They automatically
  29  * use the right size if we just have the right pointer type.
  30  *
  31  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  32  * and yet we don't want to do any pointers, because that is too much
  33  * of a performance impact. Thus we have a few rather ugly macros here,
  34  * and hide all the uglyness from the user.
  35  *
  36  * The "__xxx" versions of the user access functions are versions that
  37  * do not verify the address space, that must have been done previously
  38  * with a separate "access_ok()" call (this is used when we do multiple
  39  * accesses to the same area of user memory).
  40  *
  41  * As we use the same address space for kernel and user data on the
  42  * PowerPC, we can just do these as direct assignments.  (Of course, the
  43  * exception handling means that it's no longer "just"...)
  44  */
  45 #define get_user(x, ptr) \
  46         __get_user_check((x), (ptr), sizeof(*(ptr)))
  47 #define put_user(x, ptr) \
  48         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  49
  50 #define __get_user(x, ptr) \
  51         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  52 #define __put_user(x, ptr) \
  53         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  54
  55 extern long __put_user_bad(void);
  56
  57 #define __put_user_nocheck(x, ptr, size)                \
  58 ({                                                      \
  59         long __pu_err;                                  \
  60         __put_user_size((x), (ptr), (size), __pu_err);  \
  61         __pu_err;                                       \
  62 })
  63
  64 #define __put_user_check(x, ptr, size)                                  \
  65 ({                                                                      \
  66         long __pu_err = -EFAULT;                                        \
  67         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
  68         if (access_ok(__pu_addr, size))                 \
  69                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
  70         __pu_err;                                                       \
  71 })
  72
  73 #define __put_user_size(x, ptr, size, retval)                           \
  74 do {                                                                    \
  75         retval = 0;                                                     \
  76         switch (size) {                                                 \
  77         case 1: __put_user_asm(x, ptr, retval, "l.sb"); break;          \
  78         case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;          \
  79         case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;          \
  80         case 8: __put_user_asm2(x, ptr, retval); break;                 \
  81         default: __put_user_bad();                                      \
  82         }                                                               \
  83 } while (0)
  84
  85 struct __large_struct {
  86         unsigned long buf[100];
  87 };
  88 #define __m(x) (*(struct __large_struct *)(x))
  89
  90 /*
  91  * We don't tell gcc that we are accessing memory, but this is OK
  92  * because we do not write to any memory gcc knows about, so there
  93  * are no aliasing issues.
  94  */
  95 #define __put_user_asm(x, addr, err, op)                        \
  96         __asm__ __volatile__(                                   \
  97                 "1:     "op" 0(%2),%1\n"                        \
  98                 "2:\n"                                          \
  99                 ".section .fixup,\"ax\"\n"                      \
 100                 "3:     l.addi %0,r0,%3\n"                      \
 101                 "       l.j 2b\n"                               \
 102                 "       l.nop\n"                                \
 103                 ".previous\n"                                   \
 104                 ".section __ex_table,\"a\"\n"                   \
 105                 "       .align 2\n"                             \
 106                 "       .long 1b,3b\n"                          \
 107                 ".previous"                                     \
 108                 : "=r"(err)                                     \
 109                 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 110
 111 #define __put_user_asm2(x, addr, err)                           \
 112         __asm__ __volatile__(                                   \
 113                 "1:     l.sw 0(%2),%1\n"                        \
 114                 "2:     l.sw 4(%2),%H1\n"                       \
 115                 "3:\n"                                          \
 116                 ".section .fixup,\"ax\"\n"                      \
 117                 "4:     l.addi %0,r0,%3\n"                      \
 118                 "       l.j 3b\n"                               \
 119                 "       l.nop\n"                                \
 120                 ".previous\n"                                   \
 121                 ".section __ex_table,\"a\"\n"                   \
 122                 "       .align 2\n"                             \
 123                 "       .long 1b,4b\n"                          \
 124                 "       .long 2b,4b\n"                          \
 125                 ".previous"                                     \
 126                 : "=r"(err)                                     \
 127                 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 128
 129 #define __get_user_nocheck(x, ptr, size)                        \
 130 ({                                                              \
 131         long __gu_err;                                          \
 132         __get_user_size((x), (ptr), (size), __gu_err);          \
 133         __gu_err;                                               \
 134 })
 135
 136 #define __get_user_check(x, ptr, size)                                  \
 137 ({                                                                      \
 138         long __gu_err = -EFAULT;                                        \
 139         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 140         if (access_ok(__gu_addr, size))                                 \
 141                 __get_user_size((x), __gu_addr, (size), __gu_err);      \
 142         else                                                            \
 143                 (x) = (__typeof__(*(ptr))) 0;                           \
 144         __gu_err;                                                       \
 145 })
 146
 147 extern long __get_user_bad(void);
 148
 149 #define __get_user_size(x, ptr, size, retval)                           \
 150 do {                                                                    \
 151         retval = 0;                                                     \
 152         switch (size) {                                                 \
 153         case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break;         \
 154         case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;         \
 155         case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;         \
 156         case 8: __get_user_asm2(x, ptr, retval); break;                 \
 157         default: (x) = (__typeof__(*(ptr)))__get_user_bad();            \
 158         }                                                               \
 159 } while (0)
 160
 161 #define __get_user_asm(x, addr, err, op)                \
 162 {                                                       \
 163         unsigned long __gu_tmp;                         \
 164         __asm__ __volatile__(                           \
 165                 "1:     "op" %1,0(%2)\n"                \
 166                 "2:\n"                                  \
 167                 ".section .fixup,\"ax\"\n"              \
 168                 "3:     l.addi %0,r0,%3\n"              \
 169                 "       l.addi %1,r0,0\n"               \
 170                 "       l.j 2b\n"                       \
 171                 "       l.nop\n"                        \
 172                 ".previous\n"                           \
 173                 ".section __ex_table,\"a\"\n"           \
 174                 "       .align 2\n"                     \
 175                 "       .long 1b,3b\n"                  \
 176                 ".previous"                             \
 177                 : "=r"(err), "=r"(__gu_tmp)             \
 178                 : "r"(addr), "i"(-EFAULT), "0"(err));   \
 179         (x) = (__typeof__(*(addr)))__gu_tmp;            \
 180 }
 181
 182 #define __get_user_asm2(x, addr, err)                   \
 183 {                                                       \
 184         unsigned long long __gu_tmp;                    \
 185         __asm__ __volatile__(                           \
 186                 "1:     l.lwz %1,0(%2)\n"               \
 187                 "2:     l.lwz %H1,4(%2)\n"              \
 188                 "3:\n"                                  \
 189                 ".section .fixup,\"ax\"\n"              \
 190                 "4:     l.addi %0,r0,%3\n"              \
 191                 "       l.addi %1,r0,0\n"               \
 192                 "       l.addi %H1,r0,0\n"              \
 193                 "       l.j 3b\n"                       \
 194                 "       l.nop\n"                        \
 195                 ".previous\n"                           \
 196                 ".section __ex_table,\"a\"\n"           \
 197                 "       .align 2\n"                     \
 198                 "       .long 1b,4b\n"                  \
 199                 "       .long 2b,4b\n"                  \
 200                 ".previous"                             \
 201                 : "=r"(err), "=&r"(__gu_tmp)            \
 202                 : "r"(addr), "i"(-EFAULT), "0"(err));   \
 203         (x) = (__typeof__(*(addr)))(                    \
 204                 (__typeof__((x)-(x)))__gu_tmp);         \
 205 }
 206
 207 /* more complex routines */
 208
 209 extern unsigned long __must_check
 210 __copy_tofrom_user(void *to, const void *from, unsigned long size);
 211 static inline unsigned long
 212 raw_copy_from_user(void *to, const void __user *from, unsigned long size)
 213 {
 214         return __copy_tofrom_user(to, (__force const void *)from, size);
 215 }
 216 static inline unsigned long
 217 raw_copy_to_user(void __user *to, const void *from, unsigned long size)
 218 {
 219         return __copy_tofrom_user((__force void *)to, from, size);
 220 }
 221 #define INLINE_COPY_FROM_USER
 222 #define INLINE_COPY_TO_USER
 223
 224 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 225
 226 static inline __must_check unsigned long
 227 clear_user(void __user *addr, unsigned long size)
 228 {
 229         if (likely(access_ok(addr, size)))
 230                 size = __clear_user(addr, size);
 231         return size;
 232 }
 233
 234 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 235
 236 extern __must_check long strnlen_user(const char __user *str, long n);
 237
 238 #endif /* __ASM_OPENRISC_UACCESS_H */