blob: bc91cbab343acb8611c4e192b67d1ec296a0355b [file] [log] [blame]
Akinobu Mita6a11f752009-03-31 15:23:17 -07001#include <linux/kernel.h>
Akinobu Mita8c5fb8e2011-10-31 17:08:10 -07002#include <linux/string.h>
Akinobu Mita6a11f752009-03-31 15:23:17 -07003#include <linux/mm.h>
Akinobu Mita64212ec2011-10-31 17:08:38 -07004#include <linux/highmem.h>
Akinobu Mita6a11f752009-03-31 15:23:17 -07005#include <linux/page-debug-flags.h>
6#include <linux/poison.h>
Akinobu Mita77311132011-10-31 17:08:05 -07007#include <linux/ratelimit.h>
Akinobu Mita6a11f752009-03-31 15:23:17 -07008
9static inline void set_page_poison(struct page *page)
10{
11 __set_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
12}
13
14static inline void clear_page_poison(struct page *page)
15{
16 __clear_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
17}
18
19static inline bool page_poison(struct page *page)
20{
21 return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
22}
23
Akinobu Mita6a11f752009-03-31 15:23:17 -070024static void poison_page(struct page *page)
25{
Akinobu Mita64212ec2011-10-31 17:08:38 -070026 void *addr = kmap_atomic(page);
Akinobu Mita6a11f752009-03-31 15:23:17 -070027
Akinobu Mita6a11f752009-03-31 15:23:17 -070028 set_page_poison(page);
Akinobu Mita6a11f752009-03-31 15:23:17 -070029 memset(addr, PAGE_POISON, PAGE_SIZE);
Akinobu Mita64212ec2011-10-31 17:08:38 -070030 kunmap_atomic(addr);
Akinobu Mita6a11f752009-03-31 15:23:17 -070031}
32
33static 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
41static 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
48static void check_poison_mem(unsigned char *mem, size_t bytes)
49{
Akinobu Mita77311132011-10-31 17:08:05 -070050 static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
Akinobu Mita6a11f752009-03-31 15:23:17 -070051 unsigned char *start;
52 unsigned char *end;
53
Akinobu Mita8c5fb8e2011-10-31 17:08:10 -070054 start = memchr_inv(mem, PAGE_POISON, bytes);
55 if (!start)
Akinobu Mita6a11f752009-03-31 15:23:17 -070056 return;
57
58 for (end = mem + bytes - 1; end > start; end--) {
59 if (*end != PAGE_POISON)
60 break;
61 }
62
Akinobu Mita77311132011-10-31 17:08:05 -070063 if (!__ratelimit(&ratelimit))
Akinobu Mita6a11f752009-03-31 15:23:17 -070064 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);
Subbaraman Narayanamurthy66399732013-09-20 15:23:56 -070072 BUG_ON(PANIC_CORRUPTION);
Akinobu Mita6a11f752009-03-31 15:23:17 -070073 dump_stack();
74}
75
Akinobu Mita6a11f752009-03-31 15:23:17 -070076static void unpoison_page(struct page *page)
77{
Akinobu Mita64212ec2011-10-31 17:08:38 -070078 void *addr;
Akinobu Mita6a11f752009-03-31 15:23:17 -070079
Akinobu Mita64212ec2011-10-31 17:08:38 -070080 if (!page_poison(page))
81 return;
82
83 addr = kmap_atomic(page);
84 check_poison_mem(addr, PAGE_SIZE);
85 clear_page_poison(page);
86 kunmap_atomic(addr);
Akinobu Mita6a11f752009-03-31 15:23:17 -070087}
88
89static void unpoison_pages(struct page *page, int n)
90{
91 int i;
92
93 for (i = 0; i < n; i++)
94 unpoison_page(page + i);
95}
96
97void kernel_map_pages(struct page *page, int numpages, int enable)
98{
Akinobu Mita6a11f752009-03-31 15:23:17 -070099 if (enable)
100 unpoison_pages(page, numpages);
101 else
102 poison_pages(page, numpages);
103}