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