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
12static struct dentry *hwpoison_dir;
13
14static 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 if (!hwpoison_filter_enable)
31 goto inject;
32
33 shake_page(p: hpage);
34 /*
35 * This implies unable to support non-LRU pages except free page.
36 */
37 if (!PageLRU(page: hpage) && !PageHuge(page: p) && !is_free_buddy_page(page: p))
38 return 0;
39
40 /*
41 * do a racy check to make sure PG_hwpoison will only be set for
42 * the targeted owner (or on a free page).
43 * memory_failure() will redo the check reliably inside page lock.
44 */
45 err = hwpoison_filter(p: hpage);
46 if (err)
47 return 0;
48
49inject:
50 pr_info("Injecting memory failure at pfn %#lx\n", pfn);
51 err = memory_failure(pfn, flags: MF_SW_SIMULATED);
52 return (err == -EOPNOTSUPP) ? 0 : err;
53}
54
55static int hwpoison_unpoison(void *data, u64 val)
56{
57 if (!capable(CAP_SYS_ADMIN))
58 return -EPERM;
59
60 return unpoison_memory(pfn: val);
61}
62
63DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
64DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
65
66static void __exit pfn_inject_exit(void)
67{
68 hwpoison_filter_enable = 0;
69 debugfs_remove_recursive(dentry: hwpoison_dir);
70}
71
72static int __init pfn_inject_init(void)
73{
74 hwpoison_dir = debugfs_create_dir(name: "hwpoison", NULL);
75
76 /*
77 * Note that the below poison/unpoison interfaces do not involve
78 * hardware status change, hence do not require hardware support.
79 * They are mainly for testing hwpoison in software level.
80 */
81 debugfs_create_file(name: "corrupt-pfn", mode: 0200, parent: hwpoison_dir, NULL,
82 fops: &hwpoison_fops);
83
84 debugfs_create_file(name: "unpoison-pfn", mode: 0200, parent: hwpoison_dir, NULL,
85 fops: &unpoison_fops);
86
87 debugfs_create_u32(name: "corrupt-filter-enable", mode: 0600, parent: hwpoison_dir,
88 value: &hwpoison_filter_enable);
89
90 debugfs_create_u32(name: "corrupt-filter-dev-major", mode: 0600, parent: hwpoison_dir,
91 value: &hwpoison_filter_dev_major);
92
93 debugfs_create_u32(name: "corrupt-filter-dev-minor", mode: 0600, parent: hwpoison_dir,
94 value: &hwpoison_filter_dev_minor);
95
96 debugfs_create_u64(name: "corrupt-filter-flags-mask", mode: 0600, parent: hwpoison_dir,
97 value: &hwpoison_filter_flags_mask);
98
99 debugfs_create_u64(name: "corrupt-filter-flags-value", mode: 0600, parent: hwpoison_dir,
100 value: &hwpoison_filter_flags_value);
101
102#ifdef CONFIG_MEMCG
103 debugfs_create_u64(name: "corrupt-filter-memcg", mode: 0600, parent: hwpoison_dir,
104 value: &hwpoison_filter_memcg);
105#endif
106
107 return 0;
108}
109
110module_init(pfn_inject_init);
111module_exit(pfn_inject_exit);
112MODULE_LICENSE("GPL");
113

source code of linux/mm/hwpoison-inject.c