uaccess.h File Reference

#include <linux/preempt.h>
#include <asm/uaccess.h>

Go to the source code of this file.

Macros
#define	probe_kernel_address(addr, retval)

Functions
long	probe_kernel_read (void *dst, const void *src, size_t size)
long	__probe_kernel_read (void *dst, const void *src, size_t size)
long notrace	probe_kernel_write (void *dst, const void *src, size_t size)
long notrace	__probe_kernel_write (void *dst, const void *src, size_t size)

Macro Definition Documentation

#define probe_kernel_address	(		addr,
			retval
	)

Value:

({                      \
        long ret;               \
		mm_segment_t old_fs = get_fs();       \
							\
		set_fs(KERNEL_DS);            \
        pagefault_disable();            \
        ret = __copy_from_user_inatomic(&(retval), (__force typeof(retval) __user *)(addr), sizeof(retval));        \
        pagefault_enable();         \
        set_fs(old_fs);             \
        ret;                    \
    })

probe_kernel_address(): safely attempt to read from a location : address to read from - its type is type typeof(retval)*

Return values

read into this variable

Safely read from address into variable . If a kernel fault happens, handle that and return -EFAULT. We ensure that the __get_user() is executed in atomic context so that do_page_fault() doesn't attempt to take mmap_sem. This makes probe_kernel_address() suitable for use within regions where the caller already holds mmap_sem, or other locks which nest inside mmap_sem. This must be a macro because __get_user() needs to know the types of the args.

We don't include enough header files to be able to do the set_fs(). We require that the probe_kernel_address() caller will do that.

Definition at line 74 of file uaccess.h.

Function Documentation

long __probe_kernel_read	(	void *	dst,
		const void *	src,
		size_t	size
	)

Definition at line 21 of file maccess.c.

long notrace __probe_kernel_write	(	void *	dst,
		const void *	src,
		size_t	size
	)

Definition at line 49 of file maccess.c.

long probe_kernel_read	(	void *	dst,
		const void *	src,
		size_t	size
	)

Definition at line 19 of file maccess.c.

long notrace probe_kernel_write	(	void *	dst,
		const void *	src,
		size_t	size
	)

Definition at line 58 of file maccess.c.