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 if (!hwpoison_filter_enable)
31 goto inject;
32
33 shake_page(hpage);
34 /*
35 * This implies unable to support non-LRU pages except free page.
36 */
37 if (!PageLRU(hpage) && !PageHuge(p) && !is_free_buddy_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(hpage);
46 if (err)
47 return 0;
48
49 inject:
50 pr_info("Injecting memory failure at pfn %#lx\n", pfn);
51 err = memory_failure(pfn, MF_SW_SIMULATED);
52 return (err == -EOPNOTSUPP) ? 0 : err;
53 }
54
hwpoison_unpoison(void * data,u64 val)55 static int hwpoison_unpoison(void *data, u64 val)
56 {
57 if (!capable(CAP_SYS_ADMIN))
58 return -EPERM;
59
60 return unpoison_memory(val);
61 }
62
63 DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
64 DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
65
pfn_inject_exit(void)66 static void __exit pfn_inject_exit(void)
67 {
68 hwpoison_filter_enable = 0;
69 debugfs_remove_recursive(hwpoison_dir);
70 }
71
pfn_inject_init(void)72 static int __init pfn_inject_init(void)
73 {
74 hwpoison_dir = debugfs_create_dir("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("corrupt-pfn", 0200, hwpoison_dir, NULL,
82 &hwpoison_fops);
83
84 debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
85 &unpoison_fops);
86
87 debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
88 &hwpoison_filter_enable);
89
90 debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
91 &hwpoison_filter_dev_major);
92
93 debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
94 &hwpoison_filter_dev_minor);
95
96 debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
97 &hwpoison_filter_flags_mask);
98
99 debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
100 &hwpoison_filter_flags_value);
101
102 #ifdef CONFIG_MEMCG
103 debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
104 &hwpoison_filter_memcg);
105 #endif
106
107 return 0;
108 }
109
110 module_init(pfn_inject_init);
111 module_exit(pfn_inject_exit);
112 MODULE_LICENSE("GPL");
113
