1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Inject a hwpoison memory failure on a arbitrary pfn */
3 #include <linux/module.h>
4 #include <linux/debugfs.h>
5 #include <linux/kernel.h>
6 #include <linux/mm.h>
7 #include <linux/swap.h>
8 #include <linux/pagemap.h>
9 #include <linux/hugetlb.h>
10 #include "internal.h"
11
12 static struct dentry *hwpoison_dir;
13
hwpoison_inject(void * data,u64 val)14 static int hwpoison_inject(void *data, u64 val)
15 {
16 unsigned long pfn = val;
17 struct page *p;
18 struct page *hpage;
19 int err;
20
21 if (!capable(CAP_SYS_ADMIN))
22 return -EPERM;
23
24 if (!pfn_valid(pfn))
25 return -ENXIO;
26
27 p = pfn_to_page(pfn);
28 hpage = compound_head(p);
29 /*
30 * This implies unable to support free buddy pages.
31 */
32 if (!get_hwpoison_page(p))
33 return 0;
34
35 if (!hwpoison_filter_enable)
36 goto inject;
37
38 shake_page(hpage, 0);
39 /*
40 * This implies unable to support non-LRU pages.
41 */
42 if (!PageLRU(hpage) && !PageHuge(p))
43 goto put_out;
44
45 /*
46 * do a racy check with elevated page count, to make sure PG_hwpoison
47 * will only be set for the targeted owner (or on a free page).
48 * memory_failure() will redo the check reliably inside page lock.
49 */
50 err = hwpoison_filter(hpage);
51 if (err)
52 goto put_out;
53
54 inject:
55 pr_info("Injecting memory failure at pfn %#lx\n", pfn);
56 return memory_failure(pfn, MF_COUNT_INCREASED);
57 put_out:
58 put_hwpoison_page(p);
59 return 0;
60 }
61
hwpoison_unpoison(void * data,u64 val)62 static int hwpoison_unpoison(void *data, u64 val)
63 {
64 if (!capable(CAP_SYS_ADMIN))
65 return -EPERM;
66
67 return unpoison_memory(val);
68 }
69
70 DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
71 DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
72
pfn_inject_exit(void)73 static void pfn_inject_exit(void)
74 {
75 debugfs_remove_recursive(hwpoison_dir);
76 }
77
pfn_inject_init(void)78 static int pfn_inject_init(void)
79 {
80 hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
81
82 /*
83 * Note that the below poison/unpoison interfaces do not involve
84 * hardware status change, hence do not require hardware support.
85 * They are mainly for testing hwpoison in software level.
86 */
87 debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
88 &hwpoison_fops);
89
90 debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
91 &unpoison_fops);
92
93 debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
94 &hwpoison_filter_enable);
95
96 debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
97 &hwpoison_filter_dev_major);
98
99 debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
100 &hwpoison_filter_dev_minor);
101
102 debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
103 &hwpoison_filter_flags_mask);
104
105 debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
106 &hwpoison_filter_flags_value);
107
108 #ifdef CONFIG_MEMCG
109 debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
110 &hwpoison_filter_memcg);
111 #endif
112
113 return 0;
114 }
115
116 module_init(pfn_inject_init);
117 module_exit(pfn_inject_exit);
118 MODULE_LICENSE("GPL");
119
