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
11static struct dentry *hwpoison_dir;
12
13static 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 (!pfn_valid(pfn))
24 return -ENXIO;
25
26 p = pfn_to_page(pfn);
27 hpage = compound_head(p);
28 /*
29 * This implies unable to support free buddy pages.
30 */
31 if (!get_hwpoison_page(p))
32 return 0;
33
34 if (!hwpoison_filter_enable)
35 goto inject;
36
37 shake_page(hpage, 0);
38 /*
39 * This implies unable to support non-LRU pages.
40 */
41 if (!PageLRU(hpage) && !PageHuge(p))
42 goto put_out;
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 * memory_failure() will redo the check reliably inside page lock.
48 */
49 err = hwpoison_filter(hpage);
50 if (err)
51 goto put_out;
52
53inject:
54 pr_info("Injecting memory failure at pfn %#lx\n", pfn);
55 return memory_failure(pfn, MF_COUNT_INCREASED);
56put_out:
57 put_hwpoison_page(p);
58 return 0;
59}
60
61static 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
69DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
70DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
71
72static void pfn_inject_exit(void)
73{
74 debugfs_remove_recursive(hwpoison_dir);
75}
76
77static int pfn_inject_init(void)
78{
79 struct dentry *dentry;
80
81 hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
82 if (hwpoison_dir == NULL)
83 return -ENOMEM;
84
85 /*
86 * Note that the below poison/unpoison interfaces do not involve
87 * hardware status change, hence do not require hardware support.
88 * They are mainly for testing hwpoison in software level.
89 */
90 dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
91 NULL, &hwpoison_fops);
92 if (!dentry)
93 goto fail;
94
95 dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
96 NULL, &unpoison_fops);
97 if (!dentry)
98 goto fail;
99
100 dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
101 hwpoison_dir, &hwpoison_filter_enable);
102 if (!dentry)
103 goto fail;
104
105 dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
106 hwpoison_dir, &hwpoison_filter_dev_major);
107 if (!dentry)
108 goto fail;
109
110 dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
111 hwpoison_dir, &hwpoison_filter_dev_minor);
112 if (!dentry)
113 goto fail;
114
115 dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
116 hwpoison_dir, &hwpoison_filter_flags_mask);
117 if (!dentry)
118 goto fail;
119
120 dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
121 hwpoison_dir, &hwpoison_filter_flags_value);
122 if (!dentry)
123 goto fail;
124
125#ifdef CONFIG_MEMCG
126 dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
127 hwpoison_dir, &hwpoison_filter_memcg);
128 if (!dentry)
129 goto fail;
130#endif
131
132 return 0;
133fail:
134 pfn_inject_exit();
135 return -ENOMEM;
136}
137
138module_init(pfn_inject_init);
139module_exit(pfn_inject_exit);
140MODULE_LICENSE("GPL");
141