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);
  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");