Commit | Line | Data |
---|---|---|
7aa1c8f4 RB |
1 | #include <linux/highmem.h> |
2 | #include <linux/bootmem.h> | |
3 | #include <linux/crash_dump.h> | |
4 | #include <asm/uaccess.h> | |
5 | ||
7aa1c8f4 RB |
6 | static int __init parse_savemaxmem(char *p) |
7 | { | |
8 | if (p) | |
9 | saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1; | |
10 | ||
11 | return 1; | |
12 | } | |
13 | __setup("savemaxmem=", parse_savemaxmem); | |
14 | ||
15 | ||
16 | static void *kdump_buf_page; | |
17 | ||
18 | /** | |
19 | * copy_oldmem_page - copy one page from "oldmem" | |
20 | * @pfn: page frame number to be copied | |
21 | * @buf: target memory address for the copy; this can be in kernel address | |
22 | * space or user address space (see @userbuf) | |
23 | * @csize: number of bytes to copy | |
24 | * @offset: offset in bytes into the page (based on pfn) to begin the copy | |
25 | * @userbuf: if set, @buf is in user address space, use copy_to_user(), | |
26 | * otherwise @buf is in kernel address space, use memcpy(). | |
27 | * | |
28 | * Copy a page from "oldmem". For this page, there is no pte mapped | |
29 | * in the current kernel. | |
30 | * | |
31 | * Calling copy_to_user() in atomic context is not desirable. Hence first | |
32 | * copying the data to a pre-allocated kernel page and then copying to user | |
33 | * space in non-atomic context. | |
34 | */ | |
35 | ssize_t copy_oldmem_page(unsigned long pfn, char *buf, | |
36 | size_t csize, unsigned long offset, int userbuf) | |
37 | { | |
38 | void *vaddr; | |
39 | ||
40 | if (!csize) | |
41 | return 0; | |
42 | ||
43 | vaddr = kmap_atomic_pfn(pfn); | |
44 | ||
45 | if (!userbuf) { | |
46 | memcpy(buf, (vaddr + offset), csize); | |
47 | kunmap_atomic(vaddr); | |
48 | } else { | |
49 | if (!kdump_buf_page) { | |
50 | pr_warning("Kdump: Kdump buffer page not allocated\n"); | |
51 | ||
52 | return -EFAULT; | |
53 | } | |
54 | copy_page(kdump_buf_page, vaddr); | |
55 | kunmap_atomic(vaddr); | |
56 | if (copy_to_user(buf, (kdump_buf_page + offset), csize)) | |
57 | return -EFAULT; | |
58 | } | |
59 | ||
60 | return csize; | |
61 | } | |
62 | ||
63 | static int __init kdump_buf_page_init(void) | |
64 | { | |
65 | int ret = 0; | |
66 | ||
67 | kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL); | |
68 | if (!kdump_buf_page) { | |
69 | pr_warning("Kdump: Failed to allocate kdump buffer page\n"); | |
70 | ret = -ENOMEM; | |
71 | } | |
72 | ||
73 | return ret; | |
74 | } | |
75 | arch_initcall(kdump_buf_page_init); |