1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 *	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
 9#include <linux/errno.h>
10#include <linux/crash_dump.h>
11#include <linux/uaccess.h>
12#include <linux/io.h>
13
14/**
15 * copy_oldmem_page - copy one page from "oldmem"
16 * @pfn: page frame number to be copied
17 * @buf: target memory address for the copy; this can be in kernel address
18 *	space or user address space (see @userbuf)
19 * @csize: number of bytes to copy
20 * @offset: offset in bytes into the page (based on pfn) to begin the copy
21 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
22 *	otherwise @buf is in kernel address space, use memcpy().
23 *
24 * Copy a page from "oldmem". For this page, there is no pte mapped
25 * in the current kernel. We stitch up a pte, similar to kmap_atomic.
26 */
27ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
28		size_t csize, unsigned long offset, int userbuf)
29{
30	void  *vaddr;
31
32	if (!csize)
33		return 0;
34
35	vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
36	if (!vaddr)
37		return -ENOMEM;
38
39	if (userbuf) {
40		if (copy_to_user(buf, vaddr + offset, csize)) {
41			iounmap(vaddr);
42			return -EFAULT;
43		}
44	} else
45		memcpy(buf, vaddr + offset, csize);
46
47	set_iounmap_nonlazy();
48	iounmap(vaddr);
49	return csize;
50}

 
 1/*
 2 *	Memory preserving reboot related code.
 3 *
 4 *	Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
 5 *	Copyright (C) IBM Corporation, 2004. All rights reserved
 6 */
 7
 8#include <linux/errno.h>
 9#include <linux/crash_dump.h>
10#include <linux/uaccess.h>
11#include <linux/io.h>
12
13/**
14 * copy_oldmem_page - copy one page from "oldmem"
15 * @pfn: page frame number to be copied
16 * @buf: target memory address for the copy; this can be in kernel address
17 *	space or user address space (see @userbuf)
18 * @csize: number of bytes to copy
19 * @offset: offset in bytes into the page (based on pfn) to begin the copy
20 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
21 *	otherwise @buf is in kernel address space, use memcpy().
22 *
23 * Copy a page from "oldmem". For this page, there is no pte mapped
24 * in the current kernel. We stitch up a pte, similar to kmap_atomic.
25 */
26ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
27		size_t csize, unsigned long offset, int userbuf)
28{
29	void  *vaddr;
30
31	if (!csize)
32		return 0;
33
34	vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
35	if (!vaddr)
36		return -ENOMEM;
37
38	if (userbuf) {
39		if (copy_to_user(buf, vaddr + offset, csize)) {
40			iounmap(vaddr);
41			return -EFAULT;
42		}
43	} else
44		memcpy(buf, vaddr + offset, csize);
45
46	set_iounmap_nonlazy();
47	iounmap(vaddr);
48	return csize;
49}