1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * This code comes from arch/arm64/kernel/crash_dump.c
4  * Created by: AKASHI Takahiro <takahiro.akashi@linaro.org>
5  * Copyright (C) 2017 Linaro Limited
6  */
7 
8 #include <linux/crash_dump.h>
9 #include <linux/io.h>
10 #include <linux/uio.h>
11 
copy_oldmem_page(struct iov_iter * iter,unsigned long pfn,size_t csize,unsigned long offset)12 ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
13 			 size_t csize, unsigned long offset)
14 {
15 	void *vaddr;
16 
17 	if (!csize)
18 		return 0;
19 
20 	vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
21 	if (!vaddr)
22 		return -ENOMEM;
23 
24 	csize = copy_to_iter(vaddr + offset, csize, iter);
25 
26 	memunmap(vaddr);
27 	return csize;
28 }
29