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> |
Joonsoo Kim | e30825f | 2014-12-12 16:55:49 -0800 | [diff] [blame^] | 5 | #include <linux/page_ext.h> |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 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 | |
Joonsoo Kim | e30825f | 2014-12-12 16:55:49 -0800 | [diff] [blame^] | 9 | static bool page_poisoning_enabled __read_mostly; |
| 10 | |
| 11 | static bool need_page_poisoning(void) |
| 12 | { |
| 13 | return true; |
| 14 | } |
| 15 | |
| 16 | static void init_page_poisoning(void) |
| 17 | { |
| 18 | page_poisoning_enabled = true; |
| 19 | } |
| 20 | |
| 21 | struct page_ext_operations page_poisoning_ops = { |
| 22 | .need = need_page_poisoning, |
| 23 | .init = init_page_poisoning, |
| 24 | }; |
| 25 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 26 | static inline void set_page_poison(struct page *page) |
| 27 | { |
Joonsoo Kim | e30825f | 2014-12-12 16:55:49 -0800 | [diff] [blame^] | 28 | struct page_ext *page_ext; |
| 29 | |
| 30 | page_ext = lookup_page_ext(page); |
| 31 | __set_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 32 | } |
| 33 | |
| 34 | static inline void clear_page_poison(struct page *page) |
| 35 | { |
Joonsoo Kim | e30825f | 2014-12-12 16:55:49 -0800 | [diff] [blame^] | 36 | struct page_ext *page_ext; |
| 37 | |
| 38 | page_ext = lookup_page_ext(page); |
| 39 | __clear_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 40 | } |
| 41 | |
| 42 | static inline bool page_poison(struct page *page) |
| 43 | { |
Joonsoo Kim | e30825f | 2014-12-12 16:55:49 -0800 | [diff] [blame^] | 44 | struct page_ext *page_ext; |
| 45 | |
| 46 | page_ext = lookup_page_ext(page); |
| 47 | return test_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 48 | } |
| 49 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 50 | static void poison_page(struct page *page) |
| 51 | { |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame] | 52 | void *addr = kmap_atomic(page); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 53 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 54 | set_page_poison(page); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 55 | memset(addr, PAGE_POISON, PAGE_SIZE); |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame] | 56 | kunmap_atomic(addr); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 57 | } |
| 58 | |
| 59 | static void poison_pages(struct page *page, int n) |
| 60 | { |
| 61 | int i; |
| 62 | |
| 63 | for (i = 0; i < n; i++) |
| 64 | poison_page(page + i); |
| 65 | } |
| 66 | |
| 67 | static bool single_bit_flip(unsigned char a, unsigned char b) |
| 68 | { |
| 69 | unsigned char error = a ^ b; |
| 70 | |
| 71 | return error && !(error & (error - 1)); |
| 72 | } |
| 73 | |
| 74 | static void check_poison_mem(unsigned char *mem, size_t bytes) |
| 75 | { |
Akinobu Mita | 7731113 | 2011-10-31 17:08:05 -0700 | [diff] [blame] | 76 | static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 77 | unsigned char *start; |
| 78 | unsigned char *end; |
| 79 | |
Akinobu Mita | 8c5fb8e | 2011-10-31 17:08:10 -0700 | [diff] [blame] | 80 | start = memchr_inv(mem, PAGE_POISON, bytes); |
| 81 | if (!start) |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 82 | return; |
| 83 | |
| 84 | for (end = mem + bytes - 1; end > start; end--) { |
| 85 | if (*end != PAGE_POISON) |
| 86 | break; |
| 87 | } |
| 88 | |
Akinobu Mita | 7731113 | 2011-10-31 17:08:05 -0700 | [diff] [blame] | 89 | if (!__ratelimit(&ratelimit)) |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 90 | return; |
| 91 | else if (start == end && single_bit_flip(*start, PAGE_POISON)) |
| 92 | printk(KERN_ERR "pagealloc: single bit error\n"); |
| 93 | else |
| 94 | printk(KERN_ERR "pagealloc: memory corruption\n"); |
| 95 | |
| 96 | print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start, |
| 97 | end - start + 1, 1); |
| 98 | dump_stack(); |
| 99 | } |
| 100 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 101 | static void unpoison_page(struct page *page) |
| 102 | { |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame] | 103 | void *addr; |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 104 | |
Akinobu Mita | 64212ec | 2011-10-31 17:08:38 -0700 | [diff] [blame] | 105 | if (!page_poison(page)) |
| 106 | return; |
| 107 | |
| 108 | addr = kmap_atomic(page); |
| 109 | check_poison_mem(addr, PAGE_SIZE); |
| 110 | clear_page_poison(page); |
| 111 | kunmap_atomic(addr); |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 112 | } |
| 113 | |
| 114 | static void unpoison_pages(struct page *page, int n) |
| 115 | { |
| 116 | int i; |
| 117 | |
| 118 | for (i = 0; i < n; i++) |
| 119 | unpoison_page(page + i); |
| 120 | } |
| 121 | |
| 122 | void kernel_map_pages(struct page *page, int numpages, int enable) |
| 123 | { |
Joonsoo Kim | e30825f | 2014-12-12 16:55:49 -0800 | [diff] [blame^] | 124 | if (!page_poisoning_enabled) |
| 125 | return; |
| 126 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 127 | if (enable) |
| 128 | unpoison_pages(page, numpages); |
| 129 | else |
| 130 | poison_pages(page, numpages); |
| 131 | } |