linux-imx

/*

 *  fs/proc/vmcore.c Interface for accessing the crash

 *               dump from the system's previous life.

 *  Heavily borrowed from fs/proc/kcore.c

 *  Created by: Hariprasad Nellitheertha (hari@in.ibm.com)

 *  Copyright (C) IBM Corporation, 2004. All rights reserved

 *

 */

​

#include <linux/mm.h>

#include <linux/kcore.h>

#include <linux/user.h>

#include <linux/elf.h>

#include <linux/elfcore.h>

#include <linux/export.h>

#include <linux/slab.h>

#include <linux/highmem.h>

#include <linux/printk.h>

#include <linux/memblock.h>

#include <linux/init.h>

#include <linux/crash_dump.h>

#include <linux/list.h>

#include <linux/mutex.h>

#include <linux/vmalloc.h>

#include <linux/pagemap.h>

#include <linux/uaccess.h>

#include <linux/mem_encrypt.h>

#include <asm/pgtable.h>

#include <asm/io.h>

#include "internal.h"

​

/* List representing chunks of contiguous memory areas and their offsets in

 * vmcore file.

 */

static LIST_HEAD(vmcore_list);

​

/* Stores the pointer to the buffer containing kernel elf core headers. */

static char *elfcorebuf;

static size_t elfcorebuf_sz;

static size_t elfcorebuf_sz_orig;

​

static char *elfnotes_buf;

static size_t elfnotes_sz;

/* Size of all notes minus the device dump notes */

static size_t elfnotes_orig_sz;

​

/* Total size of vmcore file. */

static u64 vmcore_size;

​

static struct proc_dir_entry *proc_vmcore;

​

#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP

/* Device Dump list and mutex to synchronize access to list */

static LIST_HEAD(vmcoredd_list);

static DEFINE_MUTEX(vmcoredd_mutex);

#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */

​

/* Device Dump Size */

static size_t vmcoredd_orig_sz;

​

/*

 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error

 * The called function has to take care of module refcounting.

 */

static int (*oldmem_pfn_is_ram)(unsigned long pfn);

​

int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))

{

    if (oldmem_pfn_is_ram)

        return -EBUSY;

    oldmem_pfn_is_ram = fn;

    return 0;

}

EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);

​

void unregister_oldmem_pfn_is_ram(void)

{

    oldmem_pfn_is_ram = NULL;

    wmb();

}

EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);

​

static int pfn_is_ram(unsigned long pfn)

{

    int (*fn)(unsigned long pfn);

    /* pfn is ram unless fn() checks pagetype */

    int ret = 1;

​

    /*

     * Ask hypervisor if the pfn is really ram.

     * A ballooned page contains no data and reading from such a page

     * will cause high load in the hypervisor.