linux/mm/hwpoison-inject.c
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   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_page_unless_zero(hpage))
  32                return 0;
  33
  34        if (!hwpoison_filter_enable)
  35                goto inject;
  36
  37        if (!PageLRU(p) && !PageHuge(p))
  38                shake_page(p, 0);
  39        /*
  40         * This implies unable to support non-LRU pages.
  41         */
  42        if (!PageLRU(p) && !PageHuge(p))
  43                return 0;
  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         * We temporarily take page lock for try_get_mem_cgroup_from_page().
  49         * memory_failure() will redo the check reliably inside page lock.
  50         */
  51        lock_page(hpage);
  52        err = hwpoison_filter(hpage);
  53        unlock_page(hpage);
  54        if (err)
  55                return 0;
  56
  57inject:
  58        printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
  59        return memory_failure(pfn, 18, MF_COUNT_INCREASED);
  60}
  61
  62static 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
  70DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  71DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  72
  73static void pfn_inject_exit(void)
  74{
  75        if (hwpoison_dir)
  76                debugfs_remove_recursive(hwpoison_dir);
  77}
  78
  79static int pfn_inject_init(void)
  80{
  81        struct dentry *dentry;
  82
  83        hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  84        if (hwpoison_dir == NULL)
  85                return -ENOMEM;
  86
  87        /*
  88         * Note that the below poison/unpoison interfaces do not involve
  89         * hardware status change, hence do not require hardware support.
  90         * They are mainly for testing hwpoison in software level.
  91         */
  92        dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
  93                                          NULL, &hwpoison_fops);
  94        if (!dentry)
  95                goto fail;
  96
  97        dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
  98                                     NULL, &unpoison_fops);
  99        if (!dentry)
 100                goto fail;
 101
 102        dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
 103                                    hwpoison_dir, &hwpoison_filter_enable);
 104        if (!dentry)
 105                goto fail;
 106
 107        dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
 108                                    hwpoison_dir, &hwpoison_filter_dev_major);
 109        if (!dentry)
 110                goto fail;
 111
 112        dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
 113                                    hwpoison_dir, &hwpoison_filter_dev_minor);
 114        if (!dentry)
 115                goto fail;
 116
 117        dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
 118                                    hwpoison_dir, &hwpoison_filter_flags_mask);
 119        if (!dentry)
 120                goto fail;
 121
 122        dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
 123                                    hwpoison_dir, &hwpoison_filter_flags_value);
 124        if (!dentry)
 125                goto fail;
 126
 127#ifdef CONFIG_MEMCG_SWAP
 128        dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
 129                                    hwpoison_dir, &hwpoison_filter_memcg);
 130        if (!dentry)
 131                goto fail;
 132#endif
 133
 134        return 0;
 135fail:
 136        pfn_inject_exit();
 137        return -ENOMEM;
 138}
 139
 140module_init(pfn_inject_init);
 141module_exit(pfn_inject_exit);
 142MODULE_LICENSE("GPL");
 143
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