arch/loongarch/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
   4  *
   5  * Derived from MIPS:
   6  * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
   7  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   8  * Copyright (C) 2007  Maciej W. Rozycki
   9  * Copyright (C) 2014, Imagination Technologies Ltd.
  10  */
  11 #ifndef _ASM_UACCESS_H
  12 #define _ASM_UACCESS_H
  13
  14 #include <linux/kernel.h>
  15 #include <linux/string.h>
  16 #include <linux/extable.h>
  17 #include <asm/pgtable.h>
  18 #include <asm/extable.h>
  19 #include <asm/asm-extable.h>
  20 #include <asm-generic/access_ok.h>
  21
  22 extern u64 __ua_limit;
  23
  24 #define __UA_ADDR       ".dword"
  25 #define __UA_LIMIT      __ua_limit
  26
  27 /*
  28  * get_user: - Get a simple variable from user space.
  29  * @x:   Variable to store result.
  30  * @ptr: Source address, in user space.
  31  *
  32  * Context: User context only. This function may sleep if pagefaults are
  33  *          enabled.
  34  *
  35  * This macro copies a single simple variable from user space to kernel
  36  * space.  It supports simple types like char and int, but not larger
  37  * data types like structures or arrays.
  38  *
  39  * @ptr must have pointer-to-simple-variable type, and the result of
  40  * dereferencing @ptr must be assignable to @x without a cast.
  41  *
  42  * Returns zero on success, or -EFAULT on error.
  43  * On error, the variable @x is set to zero.
  44  */
  45 #define get_user(x, ptr) \
  46 ({                                                                      \
  47         const __typeof__(*(ptr)) __user *__p = (ptr);                   \
  48                                                                         \
  49         might_fault();                                                  \
  50         access_ok(__p, sizeof(*__p)) ? __get_user((x), __p) :           \
  51                                        ((x) = 0, -EFAULT);              \
  52 })
  53
  54 /*
  55  * put_user: - Write a simple value into user space.
  56  * @x:   Value to copy to user space.
  57  * @ptr: Destination address, in user space.
  58  *
  59  * Context: User context only. This function may sleep if pagefaults are
  60  *          enabled.
  61  *
  62  * This macro copies a single simple value from kernel space to user
  63  * space.  It supports simple types like char and int, but not larger
  64  * data types like structures or arrays.
  65  *
  66  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
  67  * to the result of dereferencing @ptr.
  68  *
  69  * Returns zero on success, or -EFAULT on error.
  70  */
  71 #define put_user(x, ptr) \
  72 ({                                                                      \
  73         __typeof__(*(ptr)) __user *__p = (ptr);                         \
  74                                                                         \
  75         might_fault();                                                  \
  76         access_ok(__p, sizeof(*__p)) ? __put_user((x), __p) : -EFAULT;  \
  77 })
  78
  79 /*
  80  * __get_user: - Get a simple variable from user space, with less checking.
  81  * @x:   Variable to store result.
  82  * @ptr: Source address, in user space.
  83  *
  84  * Context: User context only. This function may sleep if pagefaults are
  85  *          enabled.
  86  *
  87  * This macro copies a single simple variable from user space to kernel
  88  * space.  It supports simple types like char and int, but not larger
  89  * data types like structures or arrays.
  90  *
  91  * @ptr must have pointer-to-simple-variable type, and the result of
  92  * dereferencing @ptr must be assignable to @x without a cast.
  93  *
  94  * Caller must check the pointer with access_ok() before calling this
  95  * function.
  96  *
  97  * Returns zero on success, or -EFAULT on error.
  98  * On error, the variable @x is set to zero.
  99  */
 100 #define __get_user(x, ptr) \
 101 ({                                                                      \
 102         int __gu_err = 0;                                               \
 103                                                                         \
 104         __chk_user_ptr(ptr);                                            \
 105         __get_user_common((x), sizeof(*(ptr)), ptr);                    \
 106         __gu_err;                                                       \
 107 })
 108
 109 /*
 110  * __put_user: - Write a simple value into user space, with less checking.
 111  * @x:   Value to copy to user space.
 112  * @ptr: Destination address, in user space.
 113  *
 114  * Context: User context only. This function may sleep if pagefaults are
 115  *          enabled.
 116  *
 117  * This macro copies a single simple value from kernel space to user
 118  * space.  It supports simple types like char and int, but not larger
 119  * data types like structures or arrays.
 120  *
 121  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 122  * to the result of dereferencing @ptr.
 123  *
 124  * Caller must check the pointer with access_ok() before calling this
 125  * function.
 126  *
 127  * Returns zero on success, or -EFAULT on error.
 128  */
 129 #define __put_user(x, ptr) \
 130 ({                                                                      \
 131         int __pu_err = 0;                                               \
 132         __typeof__(*(ptr)) __pu_val;                                    \
 133                                                                         \
 134         __pu_val = (x);                                                 \
 135         __chk_user_ptr(ptr);                                            \
 136         __put_user_common(ptr, sizeof(*(ptr)));                         \
 137         __pu_err;                                                       \
 138 })
 139
 140 struct __large_struct { unsigned long buf[100]; };
 141 #define __m(x) (*(struct __large_struct __user *)(x))
 142
 143 #define __get_user_common(val, size, ptr)                               \
 144 do {                                                                    \
 145         switch (size) {                                                 \
 146         case 1: __get_data_asm(val, "ld.b", ptr); break;                \
 147         case 2: __get_data_asm(val, "ld.h", ptr); break;                \
 148         case 4: __get_data_asm(val, "ld.w", ptr); break;                \
 149         case 8: __get_data_asm(val, "ld.d", ptr); break;                \
 150         default: BUILD_BUG(); break;                                    \
 151         }                                                               \
 152 } while (0)
 153
 154 #define __get_kernel_common(val, size, ptr) __get_user_common(val, size, ptr)
 155
 156 #define __get_data_asm(val, insn, ptr)                                  \
 157 {                                                                       \
 158         long __gu_tmp;                                                  \
 159                                                                         \
 160         __asm__ __volatile__(                                           \
 161         "1:     " insn "        %1, %2                          \n"     \
 162         "2:                                                     \n"     \
 163         _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %0, %1)                   \
 164         : "+r" (__gu_err), "=r" (__gu_tmp)                              \
 165         : "m" (__m(ptr)));                                              \
 166                                                                         \
 167         (val) = (__typeof__(*(ptr))) __gu_tmp;                          \
 168 }
 169
 170 #define __put_user_common(ptr, size)                                    \
 171 do {                                                                    \
 172         switch (size) {                                                 \
 173         case 1: __put_data_asm("st.b", ptr); break;                     \
 174         case 2: __put_data_asm("st.h", ptr); break;                     \
 175         case 4: __put_data_asm("st.w", ptr); break;                     \
 176         case 8: __put_data_asm("st.d", ptr); break;                     \
 177         default: BUILD_BUG(); break;                                    \
 178         }                                                               \
 179 } while (0)
 180
 181 #define __put_kernel_common(ptr, size) __put_user_common(ptr, size)
 182
 183 #define __put_data_asm(insn, ptr)                                       \
 184 {                                                                       \
 185         __asm__ __volatile__(                                           \
 186         "1:     " insn "        %z2, %1         # __put_user_asm\n"     \
 187         "2:                                                     \n"     \
 188         _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %0)                            \
 189         : "+r" (__pu_err), "=m" (__m(ptr))                              \
 190         : "Jr" (__pu_val));                                             \
 191 }
 192
 193 #define __get_kernel_nofault(dst, src, type, err_label)                 \
 194 do {                                                                    \
 195         int __gu_err = 0;                                               \
 196                                                                         \
 197         __get_kernel_common(*((type *)(dst)), sizeof(type),             \
 198                             (__force type *)(src));                     \
 199         if (unlikely(__gu_err))                                         \
 200                 goto err_label;                                         \
 201 } while (0)
 202
 203 #define __put_kernel_nofault(dst, src, type, err_label)                 \
 204 do {                                                                    \
 205         type __pu_val;                                                  \
 206         int __pu_err = 0;                                               \
 207                                                                         \
 208         __pu_val = *(__force type *)(src);                              \
 209         __put_kernel_common(((type *)(dst)), sizeof(type));             \
 210         if (unlikely(__pu_err))                                         \
 211                 goto err_label;                                         \
 212 } while (0)
 213
 214 extern unsigned long __copy_user(void *to, const void *from, __kernel_size_t n);
 215
 216 static inline unsigned long __must_check
 217 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 218 {
 219         return __copy_user(to, (__force const void *)from, n);
 220 }
 221
 222 static inline unsigned long __must_check
 223 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 224 {
 225         return __copy_user((__force void *)to, from, n);
 226 }
 227
 228 #define INLINE_COPY_FROM_USER
 229 #define INLINE_COPY_TO_USER
 230
 231 /*
 232  * __clear_user: - Zero a block of memory in user space, with less checking.
 233  * @addr: Destination address, in user space.
 234  * @size: Number of bytes to zero.
 235  *
 236  * Zero a block of memory in user space.  Caller must check
 237  * the specified block with access_ok() before calling this function.
 238  *
 239  * Returns number of bytes that could not be cleared.
 240  * On success, this will be zero.
 241  */
 242 extern unsigned long __clear_user(void __user *addr, __kernel_size_t size);
 243
 244 #define clear_user(addr, n)                                             \
 245 ({                                                                      \
 246         void __user *__cl_addr = (addr);                                \
 247         unsigned long __cl_size = (n);                                  \
 248         if (__cl_size && access_ok(__cl_addr, __cl_size))               \
 249                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 250         __cl_size;                                                      \
 251 })
 252
 253 extern long strncpy_from_user(char *to, const char __user *from, long n);
 254 extern long strnlen_user(const char __user *str, long n);
 255
 256 #endif /* _ASM_UACCESS_H */