LXR linux/mm/hwpoison-inject.c

   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 folio *folio;
  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        folio = page_folio(p);
  29
  30        if (!hwpoison_filter_enable)
  31                goto inject;
  32
  33        shake_folio(folio);
  34        /*
  35         * This implies unable to support non-LRU pages except free page.
  36         */
  37        if (!folio_test_lru(folio) && !folio_test_hugetlb(folio) &&
  38            !is_free_buddy_page(p))
  39                return 0;
  40
  41        /*
  42         * do a racy check to make sure PG_hwpoison will only be set for
  43         * the targeted owner (or on a free page).
  44         * memory_failure() will redo the check reliably inside page lock.
  45         */
  46        err = hwpoison_filter(&folio->page);
  47        if (err)
  48                return 0;
  49
  50inject:
  51        pr_info("Injecting memory failure at pfn %#lx\n", pfn);
  52        err = memory_failure(pfn, MF_SW_SIMULATED);
  53        return (err == -EOPNOTSUPP) ? 0 : err;
  54}
  55
  56static int hwpoison_unpoison(void *data, u64 val)
  57{
  58        if (!capable(CAP_SYS_ADMIN))
  59                return -EPERM;
  60
  61        return unpoison_memory(val);
  62}
  63
  64DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  65DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  66
  67static void __exit pfn_inject_exit(void)
  68{
  69        hwpoison_filter_enable = 0;
  70        debugfs_remove_recursive(hwpoison_dir);
  71}
  72
  73static int __init pfn_inject_init(void)
  74{
  75        hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  76
  77        /*
  78         * Note that the below poison/unpoison interfaces do not involve
  79         * hardware status change, hence do not require hardware support.
  80         * They are mainly for testing hwpoison in software level.
  81         */
  82        debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
  83                            &hwpoison_fops);
  84
  85        debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
  86                            &unpoison_fops);
  87
  88        debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
  89                           &hwpoison_filter_enable);
  90
  91        debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
  92                           &hwpoison_filter_dev_major);
  93
  94        debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
  95                           &hwpoison_filter_dev_minor);
  96
  97        debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
  98                           &hwpoison_filter_flags_mask);
  99
 100        debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
 101                           &hwpoison_filter_flags_value);
 102
 103#ifdef CONFIG_MEMCG
 104        debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
 105                           &hwpoison_filter_memcg);
 106#endif
 107
 108        return 0;
 109}
 110
 111module_init(pfn_inject_init);
 112module_exit(pfn_inject_exit);
 113MODULE_DESCRIPTION("HWPoison pages injector");
 114MODULE_LICENSE("GPL");
 115