mm/hwpoison-inject.c

   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, 0);
  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");