crash_dump.c

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/*
 *  kernel/crash_dump.c - Memory preserving reboot related code.
 *
 *  Created by: Simon Horman <[email protected]>
 *  Original code moved from kernel/crash.c
 *  Original code comment copied from the i386 version of this file
 */

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/crash_dump.h>

#include <asm/page.h>
#include <asm/uaccess.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 = __va(pfn<<PAGE_SHIFT);
    if (userbuf) {
        if (copy_to_user(buf, (vaddr + offset), csize)) {
            return -EFAULT;
        }
    } else
        memcpy(buf, (vaddr + offset), csize);
    return csize;
}