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 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