LXR linux/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
   7extern void *__user_addr_min, *__user_addr_max;
   8
   9static 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
  30static void volatile_memcpy(volatile char *to, const volatile char *from, 
  31                            unsigned long n)
  32{
  33        while (n--)
  34                *(to++) = *(from++);
  35}
  36
  37static 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
  45static 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 */
  53