2
* crash_dump.c - Memory preserving reboot related code.
4
* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
5
* Copyright (C) IBM Corporation, 2004. All rights reserved
7
#include <linux/errno.h>
8
#include <linux/crash_dump.h>
10
#include <asm/uaccess.h>
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().
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.
25
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
26
size_t csize, unsigned long offset, int userbuf)
33
vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
36
if (copy_to_user(buf, (vaddr + offset), csize)) {
41
memcpy(buf, (vaddr + offset), csize);