1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * crash_dump.c - Memory preserving reboot related code.
4 *
5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
6 * Copyright (C) IBM Corporation, 2004. All rights reserved
7 */
8 #include <linux/errno.h>
9 #include <linux/crash_dump.h>
10 #include <linux/io.h>
11 #include <linux/uio.h>
12 #include <linux/uaccess.h>
13
copy_oldmem_page(struct iov_iter * iter,unsigned long pfn,size_t csize,unsigned long offset)14 ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
15 size_t csize, unsigned long offset)
16 {
17 void __iomem *vaddr;
18
19 if (!csize)
20 return 0;
21
22 vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
23 csize = copy_to_iter(vaddr + offset, csize, iter);
24 iounmap(vaddr);
25
26 return csize;
27 }
28