linux/mm/hwpoison-inject.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/* Inject a hwpoison memory failure on a arbitrary pfn */
   3#include <linux/module.h>
   4#include <linux/debugfs.h>
   5#include <linux/kernel.h>
   6#include <linux/mm.h>
   7#include <linux/swap.h>
   8#include <linux/pagemap.h>
   9#include <linux/hugetlb.h>
  10#include "internal.h"
  11
  12static struct dentry *hwpoison_dir;
  13
  14static int hwpoison_inject(void *data, u64 val)
  15{
  16        unsigned long pfn = val;
  17        struct page *p;
  18        struct page *hpage;
  19        int err;
  20
  21        if (!capable(CAP_SYS_ADMIN))
  22                return -EPERM;
  23
  24        if (!pfn_valid(pfn))
  25                return -ENXIO;
  26
  27        p = pfn_to_page(pfn);
  28        hpage = compound_head(p);
  29        /*
  30         * This implies unable to support free buddy pages.
  31         */
  32        if (!get_hwpoison_page(p))
  33                return 0;
  34
  35        if (!hwpoison_filter_enable)
  36                goto inject;
  37
  38        shake_page(hpage, 0);
  39        /*
  40         * This implies unable to support non-LRU pages.
  41         */
  42        if (!PageLRU(hpage) && !PageHuge(p))
  43                goto put_out;
  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         * memory_failure() will redo the check reliably inside page lock.
  49         */
  50        err = hwpoison_filter(hpage);
  51        if (err)
  52                goto put_out;
  53
  54inject:
  55        pr_info("Injecting memory failure at pfn %#lx\n", pfn);
  56        return memory_failure(pfn, MF_COUNT_INCREASED);
  57put_out:
  58        put_hwpoison_page(p);
  59        return 0;
  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        debugfs_remove_recursive(hwpoison_dir);
  76}
  77
  78static int pfn_inject_init(void)
  79{
  80        hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  81
  82        /*
  83         * Note that the below poison/unpoison interfaces do not involve
  84         * hardware status change, hence do not require hardware support.
  85         * They are mainly for testing hwpoison in software level.
  86         */
  87        debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
  88                            &hwpoison_fops);
  89
  90        debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
  91                            &unpoison_fops);
  92
  93        debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
  94                           &hwpoison_filter_enable);
  95
  96        debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
  97                           &hwpoison_filter_dev_major);
  98
  99        debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
 100                           &hwpoison_filter_dev_minor);
 101
 102        debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
 103                           &hwpoison_filter_flags_mask);
 104
 105        debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
 106                           &hwpoison_filter_flags_value);
 107
 108#ifdef CONFIG_MEMCG
 109        debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
 110                           &hwpoison_filter_memcg);
 111#endif
 112
 113        return 0;
 114}
 115
 116module_init(pfn_inject_init);
 117module_exit(pfn_inject_exit);
 118MODULE_LICENSE("GPL");
 119