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          * This implies unable to support free buddy pages.
  31          */
  32         if (!get_hwpoison_page(p))
  33                 return 0;
  34
  35         if (!hwpoison_filter_enable)
  36                 goto inject;
  37
  38         shake_page(hpage, 0);
  39         /*
  40          * This implies unable to support non-LRU pages.
  41          */
  42         if (!PageLRU(hpage) && !PageHuge(p))
  43                 goto put_out;
  44
  45         /*
  46          * do a racy check with elevated page count, to make sure PG_hwpoison
  47          * will only be set for the targeted owner (or on a free page).
  48          * memory_failure() will redo the check reliably inside page lock.
  49          */
  50         err = hwpoison_filter(hpage);
  51         if (err)
  52                 goto put_out;
  53
  54 inject:
  55         pr_info("Injecting memory failure at pfn %#lx\n", pfn);
  56         return memory_failure(pfn, MF_COUNT_INCREASED);
  57 put_out:
  58         put_hwpoison_page(p);
  59         return 0;
  60 }
  61
  62 static int hwpoison_unpoison(void *data, u64 val)
  63 {
  64         if (!capable(CAP_SYS_ADMIN))
  65                 return -EPERM;
  66
  67         return unpoison_memory(val);
  68 }
  69
  70 DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  71 DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  72
  73 static void pfn_inject_exit(void)
  74 {
  75         debugfs_remove_recursive(hwpoison_dir);
  76 }
  77
  78 static int pfn_inject_init(void)
  79 {
  80         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  81
  82         /*
  83          * Note that the below poison/unpoison interfaces do not involve
  84          * hardware status change, hence do not require hardware support.
  85          * They are mainly for testing hwpoison in software level.
  86          */
  87         debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
  88                             &hwpoison_fops);
  89
  90         debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
  91                             &unpoison_fops);
  92
  93         debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
  94                            &hwpoison_filter_enable);
  95
  96         debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
  97                            &hwpoison_filter_dev_major);
  98
  99         debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
 100                            &hwpoison_filter_dev_minor);
 101
 102         debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
 103                            &hwpoison_filter_flags_mask);
 104
 105         debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
 106                            &hwpoison_filter_flags_value);
 107
 108 #ifdef CONFIG_MEMCG
 109         debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
 110                            &hwpoison_filter_memcg);
 111 #endif
 112
 113         return 0;
 114 }
 115
 116 module_init(pfn_inject_init);
 117 module_exit(pfn_inject_exit);
 118 MODULE_LICENSE("GPL");