root/include/asm-generic/crash-driver.h

INCLUDED FROM

DEFINITIONS

1. map_virtual
2. unmap_virtual

#ifndef __CRASH_H__
#define __CRASH_H__

/*
 * include/linux/crash-driver.h
 *
 * Copyright (c) 2013 Red Hat, Inc. 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 as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#ifdef __KERNEL__

#include <linux/mm.h>
#include <linux/highmem.h>

static inline void *
map_virtual(u64 offset, struct page **pp)
{
        struct page *page;
        unsigned long pfn;
        void *vaddr;

        pfn = (unsigned long)(offset >> PAGE_SHIFT);

        if (!page_is_ram(pfn)) {
                printk(KERN_INFO
                    "crash memory driver: !page_is_ram(pfn: %lx)\n", pfn);
                return NULL;
        }

        if (!pfn_valid(pfn)) {
                printk(KERN_INFO
                    "crash memory driver: invalid pfn: %lx )\n", pfn);
                return NULL;
        }

        page = pfn_to_page(pfn);

        vaddr = kmap(page);
        if (!vaddr) {
                printk(KERN_INFO
                    "crash memory driver: pfn: %lx kmap(page: %lx) failed\n",
                        pfn, (unsigned long)page);
                return NULL;
        }

        *pp = page;
        return (vaddr + (offset & (PAGE_SIZE-1)));
}

static inline void unmap_virtual(struct page *page)
{
        kunmap(page);
}

#endif /* __KERNEL__ */

#endif /* __CRASH_H__ */