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 (!hwpoison_filter_enable)
  24                goto inject;
  25        if (!pfn_valid(pfn))
  26                return -ENXIO;
  27
  28        p = pfn_to_page(pfn);
  29        hpage = compound_head(p);
  30        /*
  31         * This implies unable to support free buddy pages.
  32         */
  33        if (!get_page_unless_zero(hpage))
  34                return 0;
  35
  36        if (!PageLRU(p) && !PageHuge(p))
  37                shake_page(p, 0);
  38        /*
  39         * This implies unable to support non-LRU pages.
  40         */
  41        if (!PageLRU(p) && !PageHuge(p))
  42                return 0;
  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         * We temporarily take page lock for try_get_mem_cgroup_from_page().
  48         * __memory_failure() will redo the check reliably inside page lock.
  49         */
  50        lock_page(hpage);
  51        err = hwpoison_filter(hpage);
  52        unlock_page(hpage);
  53        if (err)
  54                return 0;
  55
  56inject:
  57        printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
  58        return __memory_failure(pfn, 18, MF_COUNT_INCREASED);
  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        if (hwpoison_dir)
  75                debugfs_remove_recursive(hwpoison_dir);
  76}
  77
  78static int pfn_inject_init(void)
  79{
  80        struct dentry *dentry;
  81
  82        hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  83        if (hwpoison_dir == NULL)
  84                return -ENOMEM;
  85
  86        /*
  87         * Note that the below poison/unpoison interfaces do not involve
  88         * hardware status change, hence do not require hardware support.
  89         * They are mainly for testing hwpoison in software level.
  90         */
  91        dentry = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir,
  92                                          NULL, &hwpoison_fops);
  93        if (!dentry)
  94                goto fail;
  95
  96        dentry = debugfs_create_file("unpoison-pfn", 0600, hwpoison_dir,
  97                                     NULL, &unpoison_fops);
  98        if (!dentry)
  99                goto fail;
 100
 101        dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
 102                                    hwpoison_dir, &hwpoison_filter_enable);
 103        if (!dentry)
 104                goto fail;
 105
 106        dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
 107                                    hwpoison_dir, &hwpoison_filter_dev_major);
 108        if (!dentry)
 109                goto fail;
 110
 111        dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
 112                                    hwpoison_dir, &hwpoison_filter_dev_minor);
 113        if (!dentry)
 114                goto fail;
 115
 116        dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
 117                                    hwpoison_dir, &hwpoison_filter_flags_mask);
 118        if (!dentry)
 119                goto fail;
 120
 121        dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
 122                                    hwpoison_dir, &hwpoison_filter_flags_value);
 123        if (!dentry)
 124                goto fail;
 125
 126#ifdef  CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 127        dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
 128                                    hwpoison_dir, &hwpoison_filter_memcg);
 129        if (!dentry)
 130                goto fail;
 131#endif
 132
 133        return 0;
 134fail:
 135        pfn_inject_exit();
 136        return -ENOMEM;
 137}
 138
 139module_init(pfn_inject_init);
 140module_exit(pfn_inject_exit);
 141MODULE_LICENSE("GPL");
 142
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