1/*
 2 * User address space access functions.
 3 *
 4 *  For licencing details see kernel-base/COPYING
 5 */
 6
 7#include <linux/highmem.h>
 8#include <linux/module.h>
 
 
 
 9
10/*
11 * best effort, GUP based copy_from_user() that is NMI-safe
 
12 */
13unsigned long
14copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
15{
16	unsigned long offset, addr = (unsigned long)from;
17	unsigned long size, len = 0;
18	struct page *page;
19	void *map;
20	int ret;
21
22	do {
23		ret = __get_user_pages_fast(addr, 1, 0, &page);
24		if (!ret)
25			break;
26
27		offset = addr & (PAGE_SIZE - 1);
28		size = min(PAGE_SIZE - offset, n - len);
29
30		map = kmap_atomic(page);
31		memcpy(to, map+offset, size);
32		kunmap_atomic(map);
33		put_page(page);
34
35		len  += size;
36		to   += size;
37		addr += size;
38
39	} while (len < n);
 
 
 
 
 
 
 
40
41	return len;
42}
43EXPORT_SYMBOL_GPL(copy_from_user_nmi);

 1/*
 2 * User address space access functions.
 3 *
 4 *  For licencing details see kernel-base/COPYING
 5 */
 6
 7#include <linux/highmem.h>
 8#include <linux/export.h>
 9
10#include <asm/word-at-a-time.h>
11#include <linux/sched.h>
12
13/*
14 * We rely on the nested NMI work to allow atomic faults from the NMI path; the
15 * nested NMI paths are careful to preserve CR2.
16 */
17unsigned long
18copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
19{
20	unsigned long ret;
21
22	if (__range_not_ok(from, n, TASK_SIZE))
23		return n;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
24
25	/*
26	 * Even though this function is typically called from NMI/IRQ context
27	 * disable pagefaults so that its behaviour is consistent even when
28	 * called form other contexts.
29	 */
30	pagefault_disable();
31	ret = __copy_from_user_inatomic(to, from, n);
32	pagefault_enable();
33
34	return ret;
35}
36EXPORT_SYMBOL_GPL(copy_from_user_nmi);
37
38/**
39 * copy_to_user: - Copy a block of data into user space.
40 * @to:   Destination address, in user space.
41 * @from: Source address, in kernel space.
42 * @n:    Number of bytes to copy.
43 *
44 * Context: User context only. This function may sleep if pagefaults are
45 *          enabled.
46 *
47 * Copy data from kernel space to user space.
48 *
49 * Returns number of bytes that could not be copied.
50 * On success, this will be zero.
51 */
52unsigned long _copy_to_user(void __user *to, const void *from, unsigned n)
53{
54	if (access_ok(VERIFY_WRITE, to, n))
55		n = __copy_to_user(to, from, n);
56	return n;
57}
58EXPORT_SYMBOL(_copy_to_user);
59
60/**
61 * copy_from_user: - Copy a block of data from user space.
62 * @to:   Destination address, in kernel space.
63 * @from: Source address, in user space.
64 * @n:    Number of bytes to copy.
65 *
66 * Context: User context only. This function may sleep if pagefaults are
67 *          enabled.
68 *
69 * Copy data from user space to kernel space.
70 *
71 * Returns number of bytes that could not be copied.
72 * On success, this will be zero.
73 *
74 * If some data could not be copied, this function will pad the copied
75 * data to the requested size using zero bytes.
76 */
77unsigned long _copy_from_user(void *to, const void __user *from, unsigned n)
78{
79	if (access_ok(VERIFY_READ, from, n))
80		n = __copy_from_user(to, from, n);
81	else
82		memset(to, 0, n);
83	return n;
84}
85EXPORT_SYMBOL(_copy_from_user);