LXR linux/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
  11static struct dentry *hwpoison_dir;
  12
  13static 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
  53inject:
  54        pr_info("Injecting memory failure at pfn %#lx\n", pfn);
  55        return memory_failure(pfn, MF_COUNT_INCREASED);
  56put_out:
  57        put_hwpoison_page(p);
  58        return 0;
  59}
  60
  61static 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
  69DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  70DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  71
  72static void pfn_inject_exit(void)
  73{
  74        debugfs_remove_recursive(hwpoison_dir);
  75}
  76
  77static 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;
 133fail:
 134        pfn_inject_exit();
 135        return -ENOMEM;
 136}
 137
 138module_init(pfn_inject_init);
 139module_exit(pfn_inject_exit);
 140MODULE_LICENSE("GPL");
 141