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60e64d46 VG |
1 | /* |
2 | * kernel/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/smp_lock.h> | |
9 | #include <linux/errno.h> | |
10 | #include <linux/proc_fs.h> | |
11 | #include <linux/bootmem.h> | |
12 | #include <linux/highmem.h> | |
13 | #include <linux/crash_dump.h> | |
14 | ||
15 | #include <asm/io.h> | |
16 | #include <asm/uaccess.h> | |
17 | ||
18 | /* | |
19 | * Copy a page from "oldmem". For this page, there is no pte mapped | |
20 | * in the current kernel. We stitch up a pte, similar to kmap_atomic. | |
21 | */ | |
22 | ssize_t copy_oldmem_page(unsigned long pfn, char *buf, | |
23 | size_t csize, unsigned long offset, int userbuf) | |
24 | { | |
25 | void *page, *vaddr; | |
26 | ||
27 | if (!csize) | |
28 | return 0; | |
29 | ||
30 | page = kmalloc(PAGE_SIZE, GFP_KERNEL); | |
31 | if (!page) | |
32 | return -ENOMEM; | |
33 | ||
34 | vaddr = kmap_atomic_pfn(pfn, KM_PTE0); | |
35 | copy_page(page, vaddr); | |
36 | kunmap_atomic(vaddr, KM_PTE0); | |
37 | ||
38 | if (userbuf) { | |
39 | if (copy_to_user(buf, (page + offset), csize)) { | |
40 | kfree(page); | |
41 | return -EFAULT; | |
42 | } | |
43 | } else { | |
44 | memcpy(buf, (page + offset), csize); | |
45 | } | |
46 | ||
47 | kfree(page); | |
48 | return csize; | |
49 | } |