Root/
| 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 (!hwpoison_filter_enable) |
| 24 | goto inject; |
| 25 | if (!pfn_valid(pfn)) |
| 26 | return -ENXIO; |
| 27 | |
| 28 | p = pfn_to_page(pfn); |
| 29 | hpage = compound_head(p); |
| 30 | /* |
| 31 | * This implies unable to support free buddy pages. |
| 32 | */ |
| 33 | if (!get_page_unless_zero(hpage)) |
| 34 | return 0; |
| 35 | |
| 36 | if (!PageLRU(p) && !PageHuge(p)) |
| 37 | shake_page(p, 0); |
| 38 | /* |
| 39 | * This implies unable to support non-LRU pages. |
| 40 | */ |
| 41 | if (!PageLRU(p) && !PageHuge(p)) |
| 42 | return 0; |
| 43 | |
| 44 | /* |
| 45 | * do a racy check with elevated page count, to make sure PG_hwpoison |
| 46 | * will only be set for the targeted owner (or on a free page). |
| 47 | * We temporarily take page lock for try_get_mem_cgroup_from_page(). |
| 48 | * memory_failure() will redo the check reliably inside page lock. |
| 49 | */ |
| 50 | lock_page(hpage); |
| 51 | err = hwpoison_filter(hpage); |
| 52 | unlock_page(hpage); |
| 53 | if (err) |
| 54 | return 0; |
| 55 | |
| 56 | inject: |
| 57 | printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn); |
| 58 | return memory_failure(pfn, 18, MF_COUNT_INCREASED); |
| 59 | } |
| 60 | |
| 61 | static int hwpoison_unpoison(void *data, u64 val) |
| 62 | { |
| 63 | if (!capable(CAP_SYS_ADMIN)) |
| 64 | return -EPERM; |
| 65 | |
| 66 | return unpoison_memory(val); |
| 67 | } |
| 68 | |
| 69 | DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n"); |
| 70 | DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n"); |
| 71 | |
| 72 | static void pfn_inject_exit(void) |
| 73 | { |
| 74 | if (hwpoison_dir) |
| 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", 0600, hwpoison_dir, |
| 92 | NULL, &hwpoison_fops); |
| 93 | if (!dentry) |
| 94 | goto fail; |
| 95 | |
| 96 | dentry = debugfs_create_file("unpoison-pfn", 0600, 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_SWAP |
| 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 |
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