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
14 static int hwpoison_inject(void *data, u64 val)
15 {
16 unsigned long pfn = val;
17 struct page *p;
18 struct folio *folio;
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 folio = page_folio(p);
29
30 if (!hwpoison_filter_enable)
31 goto inject;
32
33 shake_folio(folio);
34 /*
35 * This implies unable to support non-LRU pages except free page.
36 */
37 if (!folio_test_lru(folio) && !folio_test_hugetlb(folio) &&
38 !is_free_buddy_page(p))
39 return 0;
40
41 /*
42 * do a racy check to make sure PG_hwpoison will only be set for
43 * the targeted owner (or on a free page).
44 * memory_failure() will redo the check reliably inside page lock.
45 */
46 err = hwpoison_filter(&folio->page);
47 if (err)
48 return 0;
49
50 inject:
51 pr_info("Injecting memory failure at pfn %#lx\n", pfn);
52 err = memory_failure(pfn, MF_SW_SIMULATED);
53 return (err == -EOPNOTSUPP) ? 0 : err;
54 }
55
56 static int hwpoison_unpoison(void *data, u64 val)
57 {
58 if (!capable(CAP_SYS_ADMIN))
59 return -EPERM;
60
61 return unpoison_memory(val);
62 }
63
64 DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
65 DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
66
67 static void __exit pfn_inject_exit(void)
68 {
69 hwpoison_filter_enable = 0;
70 debugfs_remove_recursive(hwpoison_dir);
71 }
72
73 static int __init pfn_inject_init(void)
74 {
75 hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
76
77 /*
78 * Note that the below poison/unpoison interfaces do not involve
79 * hardware status change, hence do not require hardware support.
80 * They are mainly for testing hwpoison in software level.
81 */
82 debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
83 &hwpoison_fops);
84
85 debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
86 &unpoison_fops);
87
88 debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
89 &hwpoison_filter_enable);
90
91 debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
92 &hwpoison_filter_dev_major);
93
94 debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
95 &hwpoison_filter_dev_minor);
96
97 debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
98 &hwpoison_filter_flags_mask);
99
100 debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
101 &hwpoison_filter_flags_value);
102
103 #ifdef CONFIG_MEMCG
104 debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
105 &hwpoison_filter_memcg);
106 #endif
107
108 return 0;
109 }
110
111 module_init(pfn_inject_init);
112 module_exit(pfn_inject_exit);
113 MODULE_DESCRIPTION("HWPoison pages injector");
114 MODULE_LICENSE("GPL");
115
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