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 
__chk_user_ptr(const volatile void * p,size_t size)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 
volatile_memcpy(volatile char * to,const volatile char * from,unsigned long n)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 
copy_from_user(void * to,const void __user volatile * from,unsigned long n)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 
copy_to_user(void __user volatile * to,const void * from,unsigned long n)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 */
53