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#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 0;
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