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1 | #include <linux/kernel.h> |
2 | #include <linux/string.h> |
3 | #include <linux/mm.h> |
4 | #include <linux/highmem.h> |
5 | #include <linux/page-debug-flags.h> |
6 | #include <linux/poison.h> |
7 | #include <linux/ratelimit.h> |
8 | |
9 | static inline void set_page_poison(struct page *page) |
10 | { |
11 | __set_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); |
12 | } |
13 | |
14 | static inline void clear_page_poison(struct page *page) |
15 | { |
16 | __clear_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); |
17 | } |
18 | |
19 | static inline bool page_poison(struct page *page) |
20 | { |
21 | return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); |
22 | } |
23 | |
24 | static void poison_page(struct page *page) |
25 | { |
26 | void *addr = kmap_atomic(page); |
27 | |
28 | set_page_poison(page); |
29 | memset(addr, PAGE_POISON, PAGE_SIZE); |
30 | kunmap_atomic(addr); |
31 | } |
32 | |
33 | static void poison_pages(struct page *page, int n) |
34 | { |
35 | int i; |
36 | |
37 | for (i = 0; i < n; i++) |
38 | poison_page(page + i); |
39 | } |
40 | |
41 | static bool single_bit_flip(unsigned char a, unsigned char b) |
42 | { |
43 | unsigned char error = a ^ b; |
44 | |
45 | return error && !(error & (error - 1)); |
46 | } |
47 | |
48 | static void check_poison_mem(unsigned char *mem, size_t bytes) |
49 | { |
50 | static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10); |
51 | unsigned char *start; |
52 | unsigned char *end; |
53 | |
54 | start = memchr_inv(mem, PAGE_POISON, bytes); |
55 | if (!start) |
56 | return; |
57 | |
58 | for (end = mem + bytes - 1; end > start; end--) { |
59 | if (*end != PAGE_POISON) |
60 | break; |
61 | } |
62 | |
63 | if (!__ratelimit(&ratelimit)) |
64 | return; |
65 | else if (start == end && single_bit_flip(*start, PAGE_POISON)) |
66 | printk(KERN_ERR "pagealloc: single bit error\n"); |
67 | else |
68 | printk(KERN_ERR "pagealloc: memory corruption\n"); |
69 | |
70 | print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start, |
71 | end - start + 1, 1); |
72 | dump_stack(); |
73 | } |
74 | |
75 | static void unpoison_page(struct page *page) |
76 | { |
77 | void *addr; |
78 | |
79 | if (!page_poison(page)) |
80 | return; |
81 | |
82 | addr = kmap_atomic(page); |
83 | check_poison_mem(addr, PAGE_SIZE); |
84 | clear_page_poison(page); |
85 | kunmap_atomic(addr); |
86 | } |
87 | |
88 | static void unpoison_pages(struct page *page, int n) |
89 | { |
90 | int i; |
91 | |
92 | for (i = 0; i < n; i++) |
93 | unpoison_page(page + i); |
94 | } |
95 | |
96 | void kernel_map_pages(struct page *page, int numpages, int enable) |
97 | { |
98 | if (enable) |
99 | unpoison_pages(page, numpages); |
100 | else |
101 | poison_pages(page, numpages); |
102 | } |
103 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9