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 (!hwpoison_filter_enable)
  24                 goto inject;
  25         if (!pfn_valid(pfn))
  26                 return -ENXIO;
  27
  28         p = pfn_to_page(pfn);
  29         hpage = compound_head(p);
  30         /*
  31          * This implies unable to support free buddy pages.
  32          */
  33         if (!get_page_unless_zero(hpage))
  34                 return 0;
  35
  36         if (!PageLRU(p) && !PageHuge(p))
  37                 shake_page(p, 0);
  38         /*
  39          * This implies unable to support non-LRU pages.
  40          */
  41         if (!PageLRU(p) && !PageHuge(p))
  42                 return 0;
  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          * We temporarily take page lock for try_get_mem_cgroup_from_page().
  48          * memory_failure() will redo the check reliably inside page lock.
  49          */
  50         lock_page(hpage);
  51         err = hwpoison_filter(hpage);
  52         unlock_page(hpage);
  53         if (err)
  54                 return 0;
  55
  56 inject:
  57         printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
  58         return memory_failure(pfn, 18, MF_COUNT_INCREASED);
  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         if (hwpoison_dir)
  75                 debugfs_remove_recursive(hwpoison_dir);
  76 }
  77
  78 static int pfn_inject_init(void)
  79 {
  80         struct dentry *dentry;
  81
  82         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  83         if (hwpoison_dir == NULL)
  84                 return -ENOMEM;
  85
  86         /*
  87          * Note that the below poison/unpoison interfaces do not involve
  88          * hardware status change, hence do not require hardware support.
  89          * They are mainly for testing hwpoison in software level.
  90          */
  91         dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
  92                                           NULL, &hwpoison_fops);
  93         if (!dentry)
  94                 goto fail;
  95
  96         dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
  97                                      NULL, &unpoison_fops);
  98         if (!dentry)
  99                 goto fail;
 100
 101         dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
 102                                     hwpoison_dir, &hwpoison_filter_enable);
 103         if (!dentry)
 104                 goto fail;
 105
 106         dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
 107                                     hwpoison_dir, &hwpoison_filter_dev_major);
 108         if (!dentry)
 109                 goto fail;
 110
 111         dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
 112                                     hwpoison_dir, &hwpoison_filter_dev_minor);
 113         if (!dentry)
 114                 goto fail;
 115
 116         dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
 117                                     hwpoison_dir, &hwpoison_filter_flags_mask);
 118         if (!dentry)
 119                 goto fail;
 120
 121         dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
 122                                     hwpoison_dir, &hwpoison_filter_flags_value);
 123         if (!dentry)
 124                 goto fail;
 125
 126 #ifdef CONFIG_MEMCG_SWAP
 127         dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
 128                                     hwpoison_dir, &hwpoison_filter_memcg);
 129         if (!dentry)
 130                 goto fail;
 131 #endif
 132
 133         return 0;
 134 fail:
 135         pfn_inject_exit();
 136         return -ENOMEM;
 137 }
 138
 139 module_init(pfn_inject_init);
 140 module_exit(pfn_inject_exit);
 141 MODULE_LICENSE("GPL");