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-generic/extable.h>
  19 #include <asm-generic/access_ok.h>
  20
  21 extern u64 __ua_limit;
  22
  23 #define __UA_ADDR       ".dword"
  24 #define __UA_LA         "la.abs"
  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         "       .section .fixup,\"ax\"                          \n"     \
 164         "3:     li.w    %0, %3                                  \n"     \
 165         "       or      %1, $r0, $r0                            \n"     \
 166         "       b       2b                                      \n"     \
 167         "       .previous                                       \n"     \
 168         "       .section __ex_table,\"a\"                       \n"     \
 169         "       "__UA_ADDR "\t1b, 3b                            \n"     \
 170         "       .previous                                       \n"     \
 171         : "+r" (__gu_err), "=r" (__gu_tmp)                              \
 172         : "m" (__m(ptr)), "i" (-EFAULT));                               \
 173                                                                         \
 174         (val) = (__typeof__(*(ptr))) __gu_tmp;                          \
 175 }
 176
 177 #define __put_user_common(ptr, size)                                    \
 178 do {                                                                    \
 179         switch (size) {                                                 \
 180         case 1: __put_data_asm("st.b", ptr); break;                     \
 181         case 2: __put_data_asm("st.h", ptr); break;                     \
 182         case 4: __put_data_asm("st.w", ptr); break;                     \
 183         case 8: __put_data_asm("st.d", ptr); break;                     \
 184         default: BUILD_BUG(); break;                                    \
 185         }                                                               \
 186 } while (0)
 187
 188 #define __put_kernel_common(ptr, size) __put_user_common(ptr, size)
 189
 190 #define __put_data_asm(insn, ptr)                                       \
 191 {                                                                       \
 192         __asm__ __volatile__(                                           \
 193         "1:     " insn "        %z2, %1         # __put_user_asm\n"     \
 194         "2:                                                     \n"     \
 195         "       .section        .fixup,\"ax\"                   \n"     \
 196         "3:     li.w    %0, %3                                  \n"     \
 197         "       b       2b                                      \n"     \
 198         "       .previous                                       \n"     \
 199         "       .section        __ex_table,\"a\"                \n"     \
 200         "       " __UA_ADDR "   1b, 3b                          \n"     \
 201         "       .previous                                       \n"     \
 202         : "+r" (__pu_err), "=m" (__m(ptr))                              \
 203         : "Jr" (__pu_val), "i" (-EFAULT));                              \
 204 }
 205
 206 #define __get_kernel_nofault(dst, src, type, err_label)                 \
 207 do {                                                                    \
 208         int __gu_err = 0;                                               \
 209                                                                         \
 210         __get_kernel_common(*((type *)(dst)), sizeof(type),             \
 211                             (__force type *)(src));                     \
 212         if (unlikely(__gu_err))                                         \
 213                 goto err_label;                                         \
 214 } while (0)
 215
 216 #define __put_kernel_nofault(dst, src, type, err_label)                 \
 217 do {                                                                    \
 218         type __pu_val;                                                  \
 219         int __pu_err = 0;                                               \
 220                                                                         \
 221         __pu_val = *(__force type *)(src);                              \
 222         __put_kernel_common(((type *)(dst)), sizeof(type));             \
 223         if (unlikely(__pu_err))                                         \
 224                 goto err_label;                                         \
 225 } while (0)
 226
 227 extern unsigned long __copy_user(void *to, const void *from, __kernel_size_t n);
 228
 229 static inline unsigned long __must_check
 230 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 231 {
 232         return __copy_user(to, from, n);
 233 }
 234
 235 static inline unsigned long __must_check
 236 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 237 {
 238         return __copy_user(to, from, n);
 239 }
 240
 241 #define INLINE_COPY_FROM_USER
 242 #define INLINE_COPY_TO_USER
 243
 244 /*
 245  * __clear_user: - Zero a block of memory in user space, with less checking.
 246  * @addr: Destination address, in user space.
 247  * @size: Number of bytes to zero.
 248  *
 249  * Zero a block of memory in user space.  Caller must check
 250  * the specified block with access_ok() before calling this function.
 251  *
 252  * Returns number of bytes that could not be cleared.
 253  * On success, this will be zero.
 254  */
 255 extern unsigned long __clear_user(void __user *addr, __kernel_size_t size);
 256
 257 #define clear_user(addr, n)                                             \
 258 ({                                                                      \
 259         void __user *__cl_addr = (addr);                                \
 260         unsigned long __cl_size = (n);                                  \
 261         if (__cl_size && access_ok(__cl_addr, __cl_size))               \
 262                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 263         __cl_size;                                                      \
 264 })
 265
 266 extern long strncpy_from_user(char *to, const char __user *from, long n);
 267 extern long strnlen_user(const char __user *str, long n);
 268
 269 #endif /* _ASM_UACCESS_H */