Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 1 | #include <linux/kernel.h> |
Akinobu Mita | 8c5fb8e | 2011-10-31 17:08:10 -0700 | [diff] [blame] | 2 | #include <linux/string.h> |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 3 | #include <linux/mm.h> |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame^] | 4 | #include <linux/highmem.h> |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 5 | #include <linux/page-debug-flags.h> |
| 6 | #include <linux/poison.h> |
Akinobu Mita | 7731113 | 2011-10-31 17:08:05 -0700 | [diff] [blame] | 7 | #include <linux/ratelimit.h> |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 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 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 24 | static void poison_page(struct page *page) |
| 25 | { |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame^] | 26 | void *addr = kmap_atomic(page); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 27 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 28 | set_page_poison(page); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 29 | memset(addr, PAGE_POISON, PAGE_SIZE); |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame^] | 30 | kunmap_atomic(addr); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 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 | { |
Akinobu Mita | 7731113 | 2011-10-31 17:08:05 -0700 | [diff] [blame] | 50 | static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 51 | unsigned char *start; |
| 52 | unsigned char *end; |
| 53 | |
Akinobu Mita | 8c5fb8e | 2011-10-31 17:08:10 -0700 | [diff] [blame] | 54 | start = memchr_inv(mem, PAGE_POISON, bytes); |
| 55 | if (!start) |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 56 | return; |
| 57 | |
| 58 | for (end = mem + bytes - 1; end > start; end--) { |
| 59 | if (*end != PAGE_POISON) |
| 60 | break; |
| 61 | } |
| 62 | |
Akinobu Mita | 7731113 | 2011-10-31 17:08:05 -0700 | [diff] [blame] | 63 | if (!__ratelimit(&ratelimit)) |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 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 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 75 | static void unpoison_page(struct page *page) |
| 76 | { |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame^] | 77 | void *addr; |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 78 | |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame^] | 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); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 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 (!debug_pagealloc_enabled) |
| 99 | return; |
| 100 | |
| 101 | if (enable) |
| 102 | unpoison_pages(page, numpages); |
| 103 | else |
| 104 | poison_pages(page, numpages); |
| 105 | } |