Commit | Line | Data |
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4d5ade5b PM |
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 | } |