Paul Mundt | 4d5ade5 | 2007-04-27 11:25:57 +0900 | [diff] [blame] | 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 | |
| 8 | #include <linux/errno.h> |
| 9 | #include <linux/crash_dump.h> |
| 10 | #include <linux/io.h> |
| 11 | #include <asm/uaccess.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 | */ |
| 26 | ssize_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(pfn << PAGE_SHIFT, PAGE_SIZE); |
| 35 | |
| 36 | if (userbuf) { |
| 37 | if (copy_to_user(buf, (vaddr + offset), csize)) { |
| 38 | iounmap(vaddr); |
| 39 | return -EFAULT; |
| 40 | } |
| 41 | } else |
| 42 | memcpy(buf, (vaddr + offset), csize); |
| 43 | |
| 44 | iounmap(vaddr); |
| 45 | return csize; |
| 46 | } |