LXR linux/mm/hwpoison-inject.c

   1/* Inject a hwpoison memory failure on a arbitary 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 "internal.h"
   9
  10static struct dentry *hwpoison_dir;
  11
  12static int hwpoison_inject(void *data, u64 val)
  13{
  14        unsigned long pfn = val;
  15        struct page *p;
  16        int err;
  17
  18        if (!capable(CAP_SYS_ADMIN))
  19                return -EPERM;
  20
  21        if (!hwpoison_filter_enable)
  22                goto inject;
  23        if (!pfn_valid(pfn))
  24                return -ENXIO;
  25
  26        p = pfn_to_page(pfn);
  27        /*
  28         * This implies unable to support free buddy pages.
  29         */
  30        if (!get_page_unless_zero(p))
  31                return 0;
  32
  33        if (!PageLRU(p))
  34                shake_page(p, 0);
  35        /*
  36         * This implies unable to support non-LRU pages.
  37         */
  38        if (!PageLRU(p))
  39                return 0;
  40
  41        /*
  42         * do a racy check with elevated page count, to make sure PG_hwpoison
  43         * will only be set for the targeted owner (or on a free page).
  44         * We temporarily take page lock for try_get_mem_cgroup_from_page().
  45         * __memory_failure() will redo the check reliably inside page lock.
  46         */
  47        lock_page(p);
  48        err = hwpoison_filter(p);
  49        unlock_page(p);
  50        if (err)
  51                return 0;
  52
  53inject:
  54        printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
  55        return __memory_failure(pfn, 18, MF_COUNT_INCREASED);
  56}
  57
  58static int hwpoison_unpoison(void *data, u64 val)
  59{
  60        if (!capable(CAP_SYS_ADMIN))
  61                return -EPERM;
  62
  63        return unpoison_memory(val);
  64}
  65
  66DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  67DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  68
  69static void pfn_inject_exit(void)
  70{
  71        if (hwpoison_dir)
  72                debugfs_remove_recursive(hwpoison_dir);
  73}
  74
  75static int pfn_inject_init(void)
  76{
  77        struct dentry *dentry;
  78
  79        hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  80        if (hwpoison_dir == NULL)
  81                return -ENOMEM;
  82
  83        /*
  84         * Note that the below poison/unpoison interfaces do not involve
  85         * hardware status change, hence do not require hardware support.
  86         * They are mainly for testing hwpoison in software level.
  87         */
  88        dentry = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir,
  89                                          NULL, &hwpoison_fops);
  90        if (!dentry)
  91                goto fail;
  92
  93        dentry = debugfs_create_file("unpoison-pfn", 0600, hwpoison_dir,
  94                                     NULL, &unpoison_fops);
  95        if (!dentry)
  96                goto fail;
  97
  98        dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
  99                                    hwpoison_dir, &hwpoison_filter_enable);
 100        if (!dentry)
 101                goto fail;
 102
 103        dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
 104                                    hwpoison_dir, &hwpoison_filter_dev_major);
 105        if (!dentry)
 106                goto fail;
 107
 108        dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
 109                                    hwpoison_dir, &hwpoison_filter_dev_minor);
 110        if (!dentry)
 111                goto fail;
 112
 113        dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
 114                                    hwpoison_dir, &hwpoison_filter_flags_mask);
 115        if (!dentry)
 116                goto fail;
 117
 118        dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
 119                                    hwpoison_dir, &hwpoison_filter_flags_value);
 120        if (!dentry)
 121                goto fail;
 122
 123#ifdef  CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 124        dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
 125                                    hwpoison_dir, &hwpoison_filter_memcg);
 126        if (!dentry)
 127                goto fail;
 128#endif
 129
 130        return 0;
 131fail:
 132        pfn_inject_exit();
 133        return -ENOMEM;
 134}
 135
 136module_init(pfn_inject_init);
 137module_exit(pfn_inject_exit);
 138MODULE_LICENSE("GPL");
 139