mm/hwpoison-inject.c

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