crash_dump.c

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/*
 * arch/arm/kernel/crash_dump.c
 *
 * Copyright (C) 2010 Nokia Corporation.
 * Author: Mika Westerberg
 *
 * This code is taken from arch/x86/kernel/crash_dump_64.c
 *   Created by: Hariprasad Nellitheertha ([email protected])
 *   Copyright (C) IBM Corporation, 2004. All rights reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/errno.h>
#include <linux/crash_dump.h>
#include <linux/uaccess.h>
#include <linux/io.h>

ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
             size_t csize, unsigned long offset,
             int userbuf)
{
    void *vaddr;

    if (!csize)
        return 0;

    vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
    if (!vaddr)
        return -ENOMEM;

    if (userbuf) {
        if (copy_to_user(buf, vaddr + offset, csize)) {
            iounmap(vaddr);
            return -EFAULT;
        }
    } else {
        memcpy(buf, vaddr + offset, csize);
    }

    iounmap(vaddr);
    return csize;
}