path: root/mm/hwpoison-inject.c (plain)
blob: 9d26fd9fefe4a1f4ec78279455c3b27f4ddbb875

1	/* Inject a hwpoison memory failure on a arbitrary pfn */
2	#include <linux/module.h>
3	#include <linux/debugfs.h>
4	#include <linux/kernel.h>
5	#include <linux/mm.h>
6	#include <linux/swap.h>
7	#include <linux/pagemap.h>
8	#include <linux/hugetlb.h>
9	#include "internal.h"
10
11	static struct dentry *hwpoison_dir;
12
13	static int hwpoison_inject(void *data, u64 val)
14	{
15	unsigned long pfn = val;
16	struct page *p;
17	struct page *hpage;
18	int err;
19
20	if (!capable(CAP_SYS_ADMIN))
21	return -EPERM;
22
23	if (!pfn_valid(pfn))
24	return -ENXIO;
25
26	p = pfn_to_page(pfn);
27	hpage = compound_head(p);
28	/*
29	* This implies unable to support free buddy pages.
30	*/
31	if (!get_hwpoison_page(p))
32	return 0;
33
34	if (!hwpoison_filter_enable)
35	goto inject;
36
37	if (!PageLRU(hpage) && !PageHuge(p))
38	shake_page(hpage, 0);
39	/*
40	* This implies unable to support non-LRU pages.
41	*/
42	if (!PageLRU(hpage) && !PageHuge(p))
43	goto put_out;
44
45	/*
46	* do a racy check with elevated page count, to make sure PG_hwpoison
47	* will only be set for the targeted owner (or on a free page).
48	* memory_failure() will redo the check reliably inside page lock.
49	*/
50	err = hwpoison_filter(hpage);
51	if (err)
52	goto put_out;
53
54	inject:
55	pr_info("Injecting memory failure at pfn %#lx\n", pfn);
56	return memory_failure(pfn, 18, MF_COUNT_INCREASED);
57	put_out:
58	put_hwpoison_page(p);
59	return 0;
60	}
61
62	static int hwpoison_unpoison(void *data, u64 val)
63	{
64	if (!capable(CAP_SYS_ADMIN))
65	return -EPERM;
66
67	return unpoison_memory(val);
68	}
69
70	DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
71	DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
72
73	static void pfn_inject_exit(void)
74	{
75	debugfs_remove_recursive(hwpoison_dir);
76	}
77
78	static int pfn_inject_init(void)
79	{
80	struct dentry *dentry;
81
82	hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
83	if (hwpoison_dir == NULL)
84	return -ENOMEM;
85
86	/*
87	* Note that the below poison/unpoison interfaces do not involve
88	* hardware status change, hence do not require hardware support.
89	* They are mainly for testing hwpoison in software level.
90	*/
91	dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
92	NULL, &hwpoison_fops);
93	if (!dentry)
94	goto fail;
95
96	dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
97	NULL, &unpoison_fops);
98	if (!dentry)
99	goto fail;
100
101	dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
102	hwpoison_dir, &hwpoison_filter_enable);
103	if (!dentry)
104	goto fail;
105
106	dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
107	hwpoison_dir, &hwpoison_filter_dev_major);
108	if (!dentry)
109	goto fail;
110
111	dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
112	hwpoison_dir, &hwpoison_filter_dev_minor);
113	if (!dentry)
114	goto fail;
115
116	dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
117	hwpoison_dir, &hwpoison_filter_flags_mask);
118	if (!dentry)
119	goto fail;
120
121	dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
122	hwpoison_dir, &hwpoison_filter_flags_value);
123	if (!dentry)
124	goto fail;
125
126	#ifdef CONFIG_MEMCG
127	dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
128	hwpoison_dir, &hwpoison_filter_memcg);
129	if (!dentry)
130	goto fail;
131	#endif
132
133	return 0;
134	fail:
135	pfn_inject_exit();
136	return -ENOMEM;
137	}
138
139	module_init(pfn_inject_init);
140	module_exit(pfn_inject_exit);
141	MODULE_LICENSE("GPL");
142