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