tools/virtio/linux/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef UACCESS_H
   3 #define UACCESS_H
   4
   5 #include <linux/compiler.h>
   6
   7 extern void *__user_addr_min, *__user_addr_max;
   8
   9 static inline void __chk_user_ptr(const volatile void *p, size_t size)
  10 {
  11         assert(p >= __user_addr_min && p + size <= __user_addr_max);
  12 }
  13
  14 #define put_user(x, ptr)                                        \
  15 ({                                                              \
  16         typeof(ptr) __pu_ptr = (ptr);                           \
  17         __chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));            \
  18         WRITE_ONCE(*(__pu_ptr), x);                             \
  19         0;                                                      \
  20 })
  21
  22 #define get_user(x, ptr)                                        \
  23 ({                                                              \
  24         typeof(ptr) __pu_ptr = (ptr);                           \
  25         __chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));            \
  26         x = READ_ONCE(*(__pu_ptr));                             \
  27         0;                                                      \
  28 })
  29
  30 static void volatile_memcpy(volatile char *to, const volatile char *from,
  31                             unsigned long n)
  32 {
  33         while (n--)
  34                 *(to++) = *(from++);
  35 }
  36
  37 static inline int copy_from_user(void *to, const void __user volatile *from,
  38                                  unsigned long n)
  39 {
  40         __chk_user_ptr(from, n);
  41         volatile_memcpy(to, from, n);
  42         return 0;
  43 }
  44
  45 static inline int copy_to_user(void __user volatile *to, const void *from,
  46                                unsigned long n)
  47 {
  48         __chk_user_ptr(to, n);
  49         volatile_memcpy(to, from, n);
  50         return 0;
  51 }
  52 #endif /* UACCESS_H */