mm/hwpoison-inject.c

   1 /* Inject a hwpoison memory failure on a arbitrary pfn */
   2 #include <linux/module.h>
   3 #include <linux/debugfs.h>
   4 #include <linux/kernel.h>
   5 #include <linux/mm.h>
   6 #include <linux/swap.h>
   7 #include <linux/pagemap.h>
   8 #include <linux/hugetlb.h>
   9 #include "internal.h"
  10
  11 static struct dentry *hwpoison_dir;
  12
  13 static int hwpoison_inject(void *data, u64 val)
  14 {
  15         unsigned long pfn = val;
  16         struct page *p;
  17         struct page *hpage;
  18         int err;
  19
  20         if (!capable(CAP_SYS_ADMIN))
  21                 return -EPERM;
  22
  23         if (!pfn_valid(pfn))
  24                 return -ENXIO;
  25
  26         p = pfn_to_page(pfn);
  27         hpage = compound_head(p);
  28         /*
  29          * This implies unable to support free buddy pages.
  30          */
  31         if (!get_hwpoison_page(p))
  32                 return 0;
  33
  34         if (!hwpoison_filter_enable)
  35                 goto inject;
  36
  37         shake_page(hpage, 0);
  38         /*
  39          * This implies unable to support non-LRU pages.
  40          */
  41         if (!PageLRU(hpage) && !PageHuge(p))
  42                 goto put_out;
  43
  44         /*
  45          * do a racy check with elevated page count, to make sure PG_hwpoison
  46          * will only be set for the targeted owner (or on a free page).
  47          * memory_failure() will redo the check reliably inside page lock.
  48          */
  49         err = hwpoison_filter(hpage);
  50         if (err)
  51                 goto put_out;
  52
  53 inject:
  54         pr_info("Injecting memory failure at pfn %#lx\n", pfn);
  55         return memory_failure(pfn, 18, MF_COUNT_INCREASED);
  56 put_out:
  57         put_hwpoison_page(p);
  58         return 0;
  59 }
  60
  61 static int hwpoison_unpoison(void *data, u64 val)
  62 {
  63         if (!capable(CAP_SYS_ADMIN))
  64                 return -EPERM;
  65
  66         return unpoison_memory(val);
  67 }
  68
  69 DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  70 DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  71
  72 static void pfn_inject_exit(void)
  73 {
  74         debugfs_remove_recursive(hwpoison_dir);
  75 }
  76
  77 static int pfn_inject_init(void)
  78 {
  79         struct dentry *dentry;
  80
  81         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  82         if (hwpoison_dir == NULL)
  83                 return -ENOMEM;
  84
  85         /*
  86          * Note that the below poison/unpoison interfaces do not involve
  87          * hardware status change, hence do not require hardware support.
  88          * They are mainly for testing hwpoison in software level.
  89          */
  90         dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
  91                                           NULL, &hwpoison_fops);
  92         if (!dentry)
  93                 goto fail;
  94
  95         dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
  96                                      NULL, &unpoison_fops);
  97         if (!dentry)
  98                 goto fail;
  99
 100         dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
 101                                     hwpoison_dir, &hwpoison_filter_enable);
 102         if (!dentry)
 103                 goto fail;
 104
 105         dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
 106                                     hwpoison_dir, &hwpoison_filter_dev_major);
 107         if (!dentry)
 108                 goto fail;
 109
 110         dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
 111                                     hwpoison_dir, &hwpoison_filter_dev_minor);
 112         if (!dentry)
 113                 goto fail;
 114
 115         dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
 116                                     hwpoison_dir, &hwpoison_filter_flags_mask);
 117         if (!dentry)
 118                 goto fail;
 119
 120         dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
 121                                     hwpoison_dir, &hwpoison_filter_flags_value);
 122         if (!dentry)
 123                 goto fail;
 124
 125 #ifdef CONFIG_MEMCG
 126         dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
 127                                     hwpoison_dir, &hwpoison_filter_memcg);
 128         if (!dentry)
 129                 goto fail;
 130 #endif
 131
 132         return 0;
 133 fail:
 134         pfn_inject_exit();
 135         return -ENOMEM;
 136 }
 137
 138 module_init(pfn_inject_init);
 139 module_exit(pfn_inject_exit);
 140 MODULE_LICENSE("GPL");