/*
* Copyright (C) 2008, 2009 Intel Corporation
* Authors: Andi Kleen, Fengguang Wu
*
* This software may be redistributed and/or modified under the terms of
* the GNU General Public License ("GPL") version 2 only as published by the
* Free Software Foundation.
*
* High level machine check handler. Handles pages reported by the
* hardware as being corrupted usually due to a 2bit ECC memory or cache
* failure.
*
* Handles page cache pages in various states. The tricky part
* here is that we can access any page asynchronous to other VM
* users, because memory failures could happen anytime and anywhere,
* possibly violating some of their assumptions. This is why this code
* has to be extremely careful. Generally it tries to use normal locking
* rules, as in get the standard locks, even if that means the
* error handling takes potentially a long time.
*
* The operation to map back from RMAP chains to processes has to walk
* the complete process list and has non linear complexity with the number
* mappings. In short it can be quite slow. But since memory corruptions
* are rare we hope to get away with this.
*/
/*
* Notebook:
* - hugetlb needs more code
* - kcore/oldmem/vmcore/mem/kmem check for hwpoison pages
* - pass bad pages to kdump next kernel
*/
#define DEBUG 1 /* remove me in 2.6.34 */
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/page-flags.h>
#include <linux/kernel-page-flags.h>
#include <linux/sched.h>
#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/backing-dev.h>
#include <linux/migrate.h>
#include <linux/page-isolation.h>
#include <linux/suspend.h>
#include <linux/slab.h>
#include <linux/swapops.h>
#include <linux/hugetlb.h>
#include "internal.h"
int sysctl_memory_failure_early_kill __read_mostly = 0;
int sysctl_memory_failure_recovery __read_mostly = 1;
atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);
#if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE)
u32 hwpoison_filter_enable = 0;
u32 hwpoison_filter_dev_major = ~0U;
u32 hwpoison_filter_dev_minor = ~0U;
u64 hwpoison_filter_flags_mask;
u64 hwpoison_filter_flags_value;
EXPORT_SYMBOL_GPL(hwpoison_filter_enable);
EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);
EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);
EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask);
EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);
static int hwpoison_filter_dev(struct page *p)
{
struct address_space *mapping;
dev_t dev;
if (hwpoison_filter_dev_major == ~0U &&
hwpoison_filter_dev_minor == ~0U)
return 0;
/*
* page_mapping() does not accept slab page
*/
if (PageSlab(p))
return -EINVAL;
mapping = page_mapping(p);
if (mapping == <