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DEFINITIONS
This source file includes following definitions.
- __copy_to_user_inatomic
- __copy_to_user
- __copy_from_user_inatomic
- __copy_from_user
- __copy_from_user_nocache
- __copy_from_user_inatomic_nocache
#ifndef ASM_X86__UACCESS_32_H
#define ASM_X86__UACCESS_32_H
/*
* User space memory access functions
*/
#include <linux/errno.h>
#include <linux/thread_info.h>
#include <linux/prefetch.h>
#include <linux/string.h>
#include <asm/asm.h>
#include <asm/page.h>
unsigned long __must_check __copy_to_user_ll
(void __user *to, const void *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll
(void *to, const void __user *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll_nozero
(void *to, const void __user *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll_nocache
(void *to, const void __user *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll_nocache_nozero
(void *to, const void __user *from, unsigned long n);
/**
* __copy_to_user_inatomic: - Copy a block of data into user space, with less checking.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
* The caller should also make sure he pins the user space address
* so that the we don't result in page fault and sleep.
*
* Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
* we return the initial request size (1, 2 or 4), as copy_*_user should do.
* If a store crosses a page boundary and gets a fault, the x86 will not write
* anything, so this is accurate.
*/
static __always_inline unsigned long __must_check
__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
{
if (__builtin_constant_p(n)) {
unsigned long ret;
switch (n) {
case 1:
__put_user_size(*(u8 *)from, (u8 __user *)to,
1, ret, 1);
return ret;
case 2:
__put_user_size(*(u16 *)from, (u16 __user *)to,
2, ret, 2);
return ret;
case 4:
__put_user_size(*(u32 *)from, (u32 __user *)to,
4, ret, 4);
return ret;
}
}
return __copy_to_user_ll(to, from, n);
}
/**
* __copy_to_user: - Copy a block of data into user space, with less checking.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*/
static __always_inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_sleep();
return __copy_to_user_inatomic(to, from, n);
}
static __always_inline unsigned long
__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
{
/* Avoid zeroing the tail if the copy fails..
* If 'n' is constant and 1, 2, or 4, we do still zero on a failure,
* but as the zeroing behaviour is only significant when n is not
* constant, that shouldn't be a problem.
*/
if (__builtin_constant_p(n)) {
unsigned long ret;
switch (n) {
case 1:
__get_user_size(*(u8 *)to, from, 1, ret, 1);
return ret;
case 2:
__get_user_size(*(u16 *)to, from, 2, ret, 2);
return ret;
case 4:
__get_user_size(*(u32 *)to, from, 4, ret, 4);
return ret;
}
}
return __copy_from_user_ll_nozero(to, from, n);
}
/**
* __copy_from_user: - Copy a block of data from user space, with less checking.
* @to: Destination address, in kernel space.
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from user space to kernel space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*
* If some data could not be copied, this function will pad the copied
* data to the requested size using zero bytes.
*
* An alternate version - __copy_from_user_inatomic() - may be called from
* atomic context and will fail rather than sleep. In this case the
* uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h
* for explanation of why this is needed.
*/
static __always_inline unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
might_sleep();
if (__builtin_constant_p(n)) {
unsigned long ret;
switch (n) {
case 1:
__get_user_size(*(u8 *)to, from, 1, ret, 1);
return ret;
case 2:
__get_user_size(*(u16 *)to, from, 2, ret, 2);
return ret;
case 4:
__get_user_size(*(u32 *)to, from, 4, ret, 4);
return ret;
}
}
return __copy_from_user_ll(to, from, n);
}
static __always_inline unsigned long __copy_from_user_nocache(void *to,
const void __user *from, unsigned long n)
{
might_sleep();
if (__builtin_constant_p(n)) {
unsigned long ret;
switch (n) {
case 1:
__get_user_size(*(u8 *)to, from, 1, ret, 1);
return ret;
case 2:
__get_user_size(*(u16 *)to, from, 2, ret, 2);
return ret;
case 4:
__get_user_size(*(u32 *)to, from, 4, ret, 4);
return ret;
}
}
return __copy_from_user_ll_nocache(to, from, n);
}
static __always_inline unsigned long
__copy_from_user_inatomic_nocache(void *to, const void __user *from,
unsigned long n)
{
return __copy_from_user_ll_nocache_nozero(to, from, n);
}
unsigned long __must_check copy_to_user(void __user *to,
const void *from, unsigned long n);
unsigned long __must_check copy_from_user(void *to,
const void __user *from,
unsigned long n);
long __must_check strncpy_from_user(char *dst, const char __user *src,
long count);
long __must_check __strncpy_from_user(char *dst,
const char __user *src, long count);
/**
* strlen_user: - Get the size of a string in user space.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
*
* Get the size of a NUL-terminated string in user space.
*
* Returns the size of the string INCLUDING the terminating NUL.
* On exception, returns 0.
*
* If there is a limit on the length of a valid string, you may wish to
* consider using strnlen_user() instead.
*/
#define strlen_user(str) strnlen_user(str, LONG_MAX)
long strnlen_user(const char __user *str, long n);
unsigned long __must_check clear_user(void __user *mem, unsigned long len);
unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
#endif /* ASM_X86__UACCESS_32_H */