1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *	kernel/crash_dump.c - Memory preserving reboot related code.
4  *
5  *	Created by: Simon Horman <horms@verge.net.au>
6  *	Original code moved from kernel/crash.c
7  *	Original code comment copied from the i386 version of this file
8  */
9 
10 #include <linux/errno.h>
11 #include <linux/types.h>
12 #include <linux/crash_dump.h>
13 #include <linux/uio.h>
14 #include <asm/page.h>
15 
copy_oldmem_page(struct iov_iter * iter,unsigned long pfn,size_t csize,unsigned long offset)16 ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
17 		size_t csize, unsigned long offset)
18 {
19 	void  *vaddr;
20 
21 	if (!csize)
22 		return 0;
23 	vaddr = __va(pfn<<PAGE_SHIFT);
24 	csize = copy_to_iter(vaddr + offset, csize, iter);
25 	return csize;
26 }
27 
28