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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_GENERIC_UACCESS_H
#define __ASM_GENERIC_UACCESS_H
/*
* User space memory access functions, these should work
* on any machine that has kernel and user data in the same
* address space, e.g. all NOMMU machines.
*/
#include <linux/string.h>
#include <asm/segment.h>
#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
#ifndef KERNEL_DS
#define KERNEL_DS MAKE_MM_SEG(~0UL)
#endif
#ifndef USER_DS
#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
#endif
#ifndef get_fs
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
static inline void set_fs(mm_segment_t fs)
{
current_thread_info()->addr_limit = fs;
}
#endif
#ifndef segment_eq
#define segment_eq(a, b) ((a).seg == (b).seg)
#endif
#define access_ok(addr, size) __access_ok((unsigned long)(addr),(size))
/*
* The architecture should really override this if possible, at least
* doing a check on the get_fs()
*/
#ifndef __access_ok
static inline int __access_ok(unsigned long addr, unsigned long size)
{
return 1;
}
#endif
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
* This version just falls back to copy_{from,to}_user, which should
* provide a fast-path for small values.
*/
#define __put_user(x, ptr) \
({ \
__typeof__(*(ptr)) __x = (x); \
int __pu_err = -EFAULT; \
__chk_user_ptr(ptr); \
switch (sizeof (*(ptr))) { \
case 1: \
case 2: \
case 4: \
case 8: \
__pu_err = __put_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
break; \
default: \
__put_user_bad(); \
break; \
} \
__pu_err; \
})
#define put_user(x, ptr) \
({ \
void __user *__p = (ptr); \
might_fault(); \
access_ok(__p, sizeof(*ptr)) ? \
__put_user((x), ((__typeof__(*(ptr)) __user *)__p)) : \
-EFAULT; \
})
#ifndef __put_user_fn
static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
{
return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0;
}
#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
#endif
extern int __put_user_bad(void) __attribute__((noreturn));
#define __get_user(x, ptr) \
({ \
int __gu_err = -EFAULT; \
__chk_user_ptr(ptr); \
switch (sizeof(*(ptr))) { \
case 1: { \
unsigned char __x = 0; \
__gu_err = __get_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 2: { \
unsigned short __x = 0; \
__gu_err = __get_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 4: { \
unsigned int __x = 0; \
__gu_err = __get_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 8: { \
unsigned long long __x = 0; \
__gu_err = __get_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
default: \
__get_user_bad(); \
break; \
} \
__gu_err; \
})
#define get_user(x, ptr) \
({ \
const void __user *__p = (ptr); \
might_fault(); \
access_ok(__p, sizeof(*ptr)) ? \
__get_user((x), (__typeof__(*(ptr)) __user *)__p) :\
((x) = (__typeof__(*(ptr)))0,-EFAULT); \
})
#ifndef __get_user_fn
static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
{
return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0;
}
#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
#endif
extern int __get_user_bad(void) __attribute__((noreturn));
/*
* Copy a null terminated string from userspace.
*/
#ifndef __strncpy_from_user
static inline long
__strncpy_from_user(char *dst, const char __user *src, long count)
{
char *tmp;
strncpy(dst, (const char __force *)src, count);
for (tmp = dst; *tmp && count > 0; tmp++, count--)
;
return (tmp - dst);
}
#endif
static inline long
strncpy_from_user(char *dst, const char __user *src, long count)
{
if (!access_ok(src, 1))
return -EFAULT;
return __strncpy_from_user(dst, src, count);
}
/*
* Return the size of a string (including the ending 0)
*
* Return 0 on exception, a value greater than N if too long
*/
#ifndef __strnlen_user
#define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
#endif
/*
* Unlike strnlen, strnlen_user includes the nul terminator in
* its returned count. Callers should check for a returned value
* greater than N as an indication the string is too long.
*/
static inline long strnlen_user(const char __user *src, long n)
{
if (!access_ok(src, 1))
return 0;
return __strnlen_user(src, n);
}
/*
* Zero Userspace
*/
#ifndef __clear_user
static inline __must_check unsigned long
__clear_user(void __user *to, unsigned long n)
{
memset((void __force *)to, 0, n);
return 0;
}
#endif
static inline __must_check unsigned long
clear_user(void __user *to, unsigned long n)
{
might_fault();
if (!access_ok(to, n))
return n;
return __clear_user(to, n);
}
#include <asm/extable.h>
#endif /* __ASM_GENERIC_UACCESS_H */
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