blob: 24f81b971403a221d64158bfba16687deb2e39a0 [file] [log] [blame]
Ingo Molnarc33fa9f2008-04-17 20:05:36 +02001/*
2 * Access kernel memory without faulting.
3 */
4#include <linux/uaccess.h>
5#include <linux/module.h>
6#include <linux/mm.h>
7
8/**
9 * probe_kernel_read(): safely attempt to read from a location
10 * @dst: pointer to the buffer that shall take the data
11 * @src: address to read from
12 * @size: size of the data chunk
13 *
14 * Safely read from address @src to the buffer at @dst. If a kernel fault
15 * happens, handle that and return -EFAULT.
16 */
17long probe_kernel_read(void *dst, void *src, size_t size)
18{
19 long ret;
20
21 pagefault_disable();
22 ret = __copy_from_user_inatomic(dst,
23 (__force const void __user *)src, size);
24 pagefault_enable();
25
26 return ret ? -EFAULT : 0;
27}
28EXPORT_SYMBOL_GPL(probe_kernel_read);
29
30/**
31 * probe_kernel_write(): safely attempt to write to a location
32 * @dst: address to write to
33 * @src: pointer to the data that shall be written
34 * @size: size of the data chunk
35 *
36 * Safely write to address @dst from the buffer at @src. If a kernel fault
37 * happens, handle that and return -EFAULT.
38 */
39long probe_kernel_write(void *dst, void *src, size_t size)
40{
41 long ret;
42
43 pagefault_disable();
44 ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
45 pagefault_enable();
46
47 return ret ? -EFAULT : 0;
48}
49EXPORT_SYMBOL_GPL(probe_kernel_write);