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hwmon: (k10temp) Add support for F15h M60h
[mirror_ubuntu-bionic-kernel.git] / mm / maccess.c
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1/*
2 * Access kernel memory without faulting.
3 */
b95f1b31 4#include <linux/export.h>
c33fa9f5 5#include <linux/mm.h>
7c7fcf76 6#include <linux/uaccess.h>
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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 */
6144a85a 17
f29c5041 18long __weak probe_kernel_read(void *dst, const void *src, size_t size)
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19 __attribute__((alias("__probe_kernel_read")));
20
f29c5041 21long __probe_kernel_read(void *dst, const void *src, size_t size)
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22{
23 long ret;
b4b8ac52 24 mm_segment_t old_fs = get_fs();
c33fa9f5 25
b4b8ac52 26 set_fs(KERNEL_DS);
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27 pagefault_disable();
28 ret = __copy_from_user_inatomic(dst,
29 (__force const void __user *)src, size);
30 pagefault_enable();
b4b8ac52 31 set_fs(old_fs);
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32
33 return ret ? -EFAULT : 0;
34}
35EXPORT_SYMBOL_GPL(probe_kernel_read);
36
37/**
38 * probe_kernel_write(): safely attempt to write to a location
39 * @dst: address to write to
40 * @src: pointer to the data that shall be written
41 * @size: size of the data chunk
42 *
43 * Safely write to address @dst from the buffer at @src. If a kernel fault
44 * happens, handle that and return -EFAULT.
45 */
f29c5041 46long __weak probe_kernel_write(void *dst, const void *src, size_t size)
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47 __attribute__((alias("__probe_kernel_write")));
48
f29c5041 49long __probe_kernel_write(void *dst, const void *src, size_t size)
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50{
51 long ret;
b4b8ac52 52 mm_segment_t old_fs = get_fs();
c33fa9f5 53
b4b8ac52 54 set_fs(KERNEL_DS);
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55 pagefault_disable();
56 ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
57 pagefault_enable();
b4b8ac52 58 set_fs(old_fs);
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59
60 return ret ? -EFAULT : 0;
61}
62EXPORT_SYMBOL_GPL(probe_kernel_write);