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1 | /* Inject a hwpoison memory failure on a arbitrary pfn */ | |
2 | #include <linux/module.h> | |
3 | #include <linux/debugfs.h> | |
4 | #include <linux/kernel.h> | |
5 | #include <linux/mm.h> | |
6 | #include <linux/swap.h> | |
7 | #include <linux/pagemap.h> | |
8 | #include <linux/hugetlb.h> | |
9 | #include "internal.h" | |
10 | ||
11 | static struct dentry *hwpoison_dir; | |
12 | ||
13 | static int hwpoison_inject(void *data, u64 val) | |
14 | { | |
15 | unsigned long pfn = val; | |
16 | struct page *p; | |
17 | struct page *hpage; | |
18 | int err; | |
19 | ||
20 | if (!capable(CAP_SYS_ADMIN)) | |
21 | return -EPERM; | |
22 | ||
23 | if (!hwpoison_filter_enable) | |
24 | goto inject; | |
25 | if (!pfn_valid(pfn)) | |
26 | return -ENXIO; | |
27 | ||
28 | p = pfn_to_page(pfn); | |
29 | hpage = compound_head(p); | |
30 | /* | |
31 | * This implies unable to support free buddy pages. | |
32 | */ | |
33 | if (!get_page_unless_zero(hpage)) | |
34 | return 0; | |
35 | ||
36 | if (!PageLRU(p) && !PageHuge(p)) | |
37 | shake_page(p, 0); | |
38 | /* | |
39 | * This implies unable to support non-LRU pages. | |
40 | */ | |
41 | if (!PageLRU(p) && !PageHuge(p)) | |
42 | return 0; | |
43 | ||
44 | /* | |
45 | * do a racy check with elevated page count, to make sure PG_hwpoison | |
46 | * will only be set for the targeted owner (or on a free page). | |
47 | * We temporarily take page lock for try_get_mem_cgroup_from_page(). | |
48 | * memory_failure() will redo the check reliably inside page lock. | |
49 | */ | |
50 | lock_page(hpage); | |
51 | err = hwpoison_filter(hpage); | |
52 | unlock_page(hpage); | |
53 | if (err) | |
54 | return 0; | |
55 | ||
56 | inject: | |
57 | printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn); | |
58 | return memory_failure(pfn, 18, MF_COUNT_INCREASED); | |
59 | } | |
60 | ||
61 | static int hwpoison_unpoison(void *data, u64 val) | |
62 | { | |
63 | if (!capable(CAP_SYS_ADMIN)) | |
64 | return -EPERM; | |
65 | ||
66 | return unpoison_memory(val); | |
67 | } | |
68 | ||
69 | DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n"); | |
70 | DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n"); | |
71 | ||
72 | static void pfn_inject_exit(void) | |
73 | { | |
74 | if (hwpoison_dir) | |
75 | debugfs_remove_recursive(hwpoison_dir); | |
76 | } | |
77 | ||
78 | static int pfn_inject_init(void) | |
79 | { | |
80 | struct dentry *dentry; | |
81 | ||
82 | hwpoison_dir = debugfs_create_dir("hwpoison", NULL); | |
83 | if (hwpoison_dir == NULL) | |
84 | return -ENOMEM; | |
85 | ||
86 | /* | |
87 | * Note that the below poison/unpoison interfaces do not involve | |
88 | * hardware status change, hence do not require hardware support. | |
89 | * They are mainly for testing hwpoison in software level. | |
90 | */ | |
91 | dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, | |
92 | NULL, &hwpoison_fops); | |
93 | if (!dentry) | |
94 | goto fail; | |
95 | ||
96 | dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, | |
97 | NULL, &unpoison_fops); | |
98 | if (!dentry) | |
99 | goto fail; | |
100 | ||
101 | dentry = debugfs_create_u32("corrupt-filter-enable", 0600, | |
102 | hwpoison_dir, &hwpoison_filter_enable); | |
103 | if (!dentry) | |
104 | goto fail; | |
105 | ||
106 | dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600, | |
107 | hwpoison_dir, &hwpoison_filter_dev_major); | |
108 | if (!dentry) | |
109 | goto fail; | |
110 | ||
111 | dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600, | |
112 | hwpoison_dir, &hwpoison_filter_dev_minor); | |
113 | if (!dentry) | |
114 | goto fail; | |
115 | ||
116 | dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600, | |
117 | hwpoison_dir, &hwpoison_filter_flags_mask); | |
118 | if (!dentry) | |
119 | goto fail; | |
120 | ||
121 | dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600, | |
122 | hwpoison_dir, &hwpoison_filter_flags_value); | |
123 | if (!dentry) | |
124 | goto fail; | |
125 | ||
126 | #ifdef CONFIG_MEMCG_SWAP | |
127 | dentry = debugfs_create_u64("corrupt-filter-memcg", 0600, | |
128 | hwpoison_dir, &hwpoison_filter_memcg); | |
129 | if (!dentry) | |
130 | goto fail; | |
131 | #endif | |
132 | ||
133 | return 0; | |
134 | fail: | |
135 | pfn_inject_exit(); | |
136 | return -ENOMEM; | |
137 | } | |
138 | ||
139 | module_init(pfn_inject_init); | |
140 | module_exit(pfn_inject_exit); | |
141 | MODULE_LICENSE("GPL"); |