xref: /openbmc/linux/mm/hwpoison-inject.c (revision bfa87ac8)
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 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 
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 
66 static void __exit pfn_inject_exit(void)
67 {
68 	hwpoison_filter_enable = 0;
69 	debugfs_remove_recursive(hwpoison_dir);
70 }
71 
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