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

 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
14ssize_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}