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