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, 0);
34 /*
35 * This implies unable to support non-LRU pages.
36 */
37 if (!PageLRU(hpage) && !PageHuge(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 return memory_failure(pfn, 0);
52 }
53
hwpoison_unpoison(void * data,u64 val)54 static int hwpoison_unpoison(void *data, u64 val)
55 {
56 if (!capable(CAP_SYS_ADMIN))
57 return -EPERM;
58
59 return unpoison_memory(val);
60 }
61
62 DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
63 DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
64
pfn_inject_exit(void)65 static void pfn_inject_exit(void)
66 {
67 debugfs_remove_recursive(hwpoison_dir);
68 }
69
pfn_inject_init(void)70 static int pfn_inject_init(void)
71 {
72 hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
73
74 /*
75 * Note that the below poison/unpoison interfaces do not involve
76 * hardware status change, hence do not require hardware support.
77 * They are mainly for testing hwpoison in software level.
78 */
79 debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
80 &hwpoison_fops);
81
82 debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
83 &unpoison_fops);
84
85 debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
86 &hwpoison_filter_enable);
87
88 debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
89 &hwpoison_filter_dev_major);
90
91 debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
92 &hwpoison_filter_dev_minor);
93
94 debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
95 &hwpoison_filter_flags_mask);
96
97 debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
98 &hwpoison_filter_flags_value);
99
100 #ifdef CONFIG_MEMCG
101 debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
102 &hwpoison_filter_memcg);
103 #endif
104
105 return 0;
106 }
107
108 module_init(pfn_inject_init);
109 module_exit(pfn_inject_exit);
110 MODULE_LICENSE("GPL");
111