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
16ssize_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