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 except free page. 36 */ 37 if (!PageLRU(hpage) && !PageHuge(p) && !is_free_buddy_page(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 err = memory_failure(pfn, MF_SW_SIMULATED); 52 return (err == -EOPNOTSUPP) ? 0 : err; 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_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n"); 64 DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n"); 65 66 static void pfn_inject_exit(void) 67 { 68 hwpoison_filter_enable = 0; 69 debugfs_remove_recursive(hwpoison_dir); 70 } 71 72 static int pfn_inject_init(void) 73 { 74 hwpoison_dir = debugfs_create_dir("hwpoison", NULL); 75 76 /* 77 * Note that the below poison/unpoison interfaces do not involve 78 * hardware status change, hence do not require hardware support. 79 * They are mainly for testing hwpoison in software level. 80 */ 81 debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL, 82 &hwpoison_fops); 83 84 debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL, 85 &unpoison_fops); 86 87 debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir, 88 &hwpoison_filter_enable); 89 90 debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir, 91 &hwpoison_filter_dev_major); 92 93 debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir, 94 &hwpoison_filter_dev_minor); 95 96 debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir, 97 &hwpoison_filter_flags_mask); 98 99 debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir, 100 &hwpoison_filter_flags_value); 101 102 #ifdef CONFIG_MEMCG 103 debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir, 104 &hwpoison_filter_memcg); 105 #endif 106 107 return 0; 108 } 109 110 module_init(pfn_inject_init); 111 module_exit(pfn_inject_exit); 112 MODULE_LICENSE("GPL"); 113