1/*
 2 * arch/arm/kernel/crash_dump.c
 3 *
 4 * Copyright (C) 2010 Nokia Corporation.
 5 * Author: Mika Westerberg
 6 *
 7 * This code is taken from arch/x86/kernel/crash_dump_64.c
 8 *   Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
 9 *   Copyright (C) IBM Corporation, 2004. All rights reserved
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16#include <linux/errno.h>
17#include <linux/crash_dump.h>
18#include <linux/uaccess.h>
19#include <linux/io.h>
20
21/**
22 * copy_oldmem_page() - copy one page from old kernel memory
23 * @pfn: page frame number to be copied
24 * @buf: buffer where the copied page is placed
25 * @csize: number of bytes to copy
26 * @offset: offset in bytes into the page
27 * @userbuf: if set, @buf is int he user address space
28 *
29 * This function copies one page from old kernel memory into buffer pointed by
30 * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
31 * copied or negative error in case of failure.
32 */
33ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
34			 size_t csize, unsigned long offset,
35			 int userbuf)
36{
37	void *vaddr;
38
39	if (!csize)
40		return 0;
41
42	vaddr = ioremap(__pfn_to_phys(pfn), PAGE_SIZE);
43	if (!vaddr)
44		return -ENOMEM;
45
46	if (userbuf) {
47		if (copy_to_user(buf, vaddr + offset, csize)) {
48			iounmap(vaddr);
49			return -EFAULT;
50		}
51	} else {
52		memcpy(buf, vaddr + offset, csize);
53	}
54
55	iounmap(vaddr);
56	return csize;
57}

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * arch/arm/kernel/crash_dump.c
 4 *
 5 * Copyright (C) 2010 Nokia Corporation.
 6 * Author: Mika Westerberg
 7 *
 8 * This code is taken from arch/x86/kernel/crash_dump_64.c
 9 *   Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
10 *   Copyright (C) IBM Corporation, 2004. All rights reserved
 
 
 
 
11 */
12
13#include <linux/errno.h>
14#include <linux/crash_dump.h>
15#include <linux/uaccess.h>
16#include <linux/io.h>
17
18/**
19 * copy_oldmem_page() - copy one page from old kernel memory
20 * @pfn: page frame number to be copied
21 * @buf: buffer where the copied page is placed
22 * @csize: number of bytes to copy
23 * @offset: offset in bytes into the page
24 * @userbuf: if set, @buf is int he user address space
25 *
26 * This function copies one page from old kernel memory into buffer pointed by
27 * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
28 * copied or negative error in case of failure.
29 */
30ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
31			 size_t csize, unsigned long offset,
32			 int userbuf)
33{
34	void *vaddr;
35
36	if (!csize)
37		return 0;
38
39	vaddr = ioremap(__pfn_to_phys(pfn), PAGE_SIZE);
40	if (!vaddr)
41		return -ENOMEM;
42
43	if (userbuf) {
44		if (copy_to_user(buf, vaddr + offset, csize)) {
45			iounmap(vaddr);
46			return -EFAULT;
47		}
48	} else {
49		memcpy(buf, vaddr + offset, csize);
50	}
51
52	iounmap(vaddr);
53	return csize;
54}