1/*
 2 * User address space access functions.
 3 *
 4 *  For licencing details see kernel-base/COPYING
 5 */
 6
 7#include <linux/uaccess.h>
 8#include <linux/export.h>
 9
10/*
11 * We rely on the nested NMI work to allow atomic faults from the NMI path; the
12 * nested NMI paths are careful to preserve CR2.
13 */
14unsigned long
15copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
16{
17	unsigned long ret;
 
 
 
 
18
19	if (__range_not_ok(from, n, TASK_SIZE))
20		return n;
 
 
21
22	/*
23	 * Even though this function is typically called from NMI/IRQ context
24	 * disable pagefaults so that its behaviour is consistent even when
25	 * called form other contexts.
26	 */
27	pagefault_disable();
28	ret = __copy_from_user_inatomic(to, from, n);
29	pagefault_enable();
30
31	return ret;
 
 
 
 
 
 
 
 
 
 
 
32}
33EXPORT_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/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);