HWPOISON: Add soft page offline support
[linux-2.6.git] / mm / hwpoison-inject.c
1 /* Inject a hwpoison memory failure on a arbitary 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 "internal.h"
9
10 static struct dentry *hwpoison_dir;
11
12 static int hwpoison_inject(void *data, u64 val)
13 {
14         unsigned long pfn = val;
15         struct page *p;
16         int err;
17
18         if (!capable(CAP_SYS_ADMIN))
19                 return -EPERM;
20
21         if (!pfn_valid(pfn))
22                 return -ENXIO;
23
24         p = pfn_to_page(pfn);
25         /*
26          * This implies unable to support free buddy pages.
27          */
28         if (!get_page_unless_zero(p))
29                 return 0;
30
31         if (!PageLRU(p))
32                 shake_page(p, 0);
33         /*
34          * This implies unable to support non-LRU pages.
35          */
36         if (!PageLRU(p))
37                 return 0;
38
39         /*
40          * do a racy check with elevated page count, to make sure PG_hwpoison
41          * will only be set for the targeted owner (or on a free page).
42          * We temporarily take page lock for try_get_mem_cgroup_from_page().
43          * __memory_failure() will redo the check reliably inside page lock.
44          */
45         lock_page(p);
46         err = hwpoison_filter(p);
47         unlock_page(p);
48         if (err)
49                 return 0;
50
51         printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
52         return __memory_failure(pfn, 18, MF_COUNT_INCREASED);
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_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
64 DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
65
66 static void pfn_inject_exit(void)
67 {
68         if (hwpoison_dir)
69                 debugfs_remove_recursive(hwpoison_dir);
70 }
71
72 static int pfn_inject_init(void)
73 {
74         struct dentry *dentry;
75
76         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
77         if (hwpoison_dir == NULL)
78                 return -ENOMEM;
79
80         /*
81          * Note that the below poison/unpoison interfaces do not involve
82          * hardware status change, hence do not require hardware support.
83          * They are mainly for testing hwpoison in software level.
84          */
85         dentry = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir,
86                                           NULL, &hwpoison_fops);
87         if (!dentry)
88                 goto fail;
89
90         dentry = debugfs_create_file("unpoison-pfn", 0600, hwpoison_dir,
91                                      NULL, &unpoison_fops);
92         if (!dentry)
93                 goto fail;
94
95         dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
96                                     hwpoison_dir, &hwpoison_filter_enable);
97         if (!dentry)
98                 goto fail;
99
100         dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
101                                     hwpoison_dir, &hwpoison_filter_dev_major);
102         if (!dentry)
103                 goto fail;
104
105         dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
106                                     hwpoison_dir, &hwpoison_filter_dev_minor);
107         if (!dentry)
108                 goto fail;
109
110         dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
111                                     hwpoison_dir, &hwpoison_filter_flags_mask);
112         if (!dentry)
113                 goto fail;
114
115         dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
116                                     hwpoison_dir, &hwpoison_filter_flags_value);
117         if (!dentry)
118                 goto fail;
119
120 #ifdef  CONFIG_CGROUP_MEM_RES_CTLR_SWAP
121         dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
122                                     hwpoison_dir, &hwpoison_filter_memcg);
123         if (!dentry)
124                 goto fail;
125 #endif
126
127         return 0;
128 fail:
129         pfn_inject_exit();
130         return -ENOMEM;
131 }
132
133 module_init(pfn_inject_init);
134 module_exit(pfn_inject_exit);
135 MODULE_LICENSE("GPL");