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. 36 */ 37 if (!PageLRU(hpage) && !PageHuge(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 return memory_failure(pfn, 0); 52 } 53 54 static int hwpoison_unpoison(void *data, u64 val) 55 { 56 if (!capable(CAP_SYS_ADMIN)) 57 return -EPERM; 58 59 return unpoison_memory(val); 60 } 61 62 DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n"); 63 DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n"); 64 65 static void pfn_inject_exit(void) 66 { 67 debugfs_remove_recursive(hwpoison_dir); 68 } 69 70 static int pfn_inject_init(void) 71 { 72 hwpoison_dir = debugfs_create_dir("hwpoison", NULL); 73 74 /* 75 * Note that the below poison/unpoison interfaces do not involve 76 * hardware status change, hence do not require hardware support. 77 * They are mainly for testing hwpoison in software level. 78 */ 79 debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL, 80 &hwpoison_fops); 81 82 debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL, 83 &unpoison_fops); 84 85 debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir, 86 &hwpoison_filter_enable); 87 88 debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir, 89 &hwpoison_filter_dev_major); 90 91 debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir, 92 &hwpoison_filter_dev_minor); 93 94 debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir, 95 &hwpoison_filter_flags_mask); 96 97 debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir, 98 &hwpoison_filter_flags_value); 99 100 #ifdef CONFIG_MEMCG 101 debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir, 102 &hwpoison_filter_memcg); 103 #endif 104 105 return 0; 106 } 107 108 module_init(pfn_inject_init); 109 module_exit(pfn_inject_exit); 110 MODULE_LICENSE("GPL"); 111