LXR linux/arch/arm/kernel/crash

   1/*
   2 * arch/arm/kernel/crash_dump.c
   3 *
   4 * Copyright (C) 2010 Nokia Corporation.
   5 * Author: Mika Westerberg
   6 *
   7 * This code is taken from arch/x86/kernel/crash_dump_64.c
   8 *   Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
   9 *   Copyright (C) IBM Corporation, 2004. All rights reserved
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License version 2 as
  13 * published by the Free Software Foundation.
  14 */
  15
  16#include <linux/errno.h>
  17#include <linux/crash_dump.h>
  18#include <linux/uaccess.h>
  19#include <linux/io.h>
  20
  21/**
  22 * copy_oldmem_page() - copy one page from old kernel memory
  23 * @pfn: page frame number to be copied
  24 * @buf: buffer where the copied page is placed
  25 * @csize: number of bytes to copy
  26 * @offset: offset in bytes into the page
  27 * @userbuf: if set, @buf is int he user address space
  28 *
  29 * This function copies one page from old kernel memory into buffer pointed by
  30 * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
  31 * copied or negative error in case of failure.
  32 */
  33ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
  34                         size_t csize, unsigned long offset,
  35                         int userbuf)
  36{
  37        void *vaddr;
  38
  39        if (!csize)
  40                return 0;
  41
  42        vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
  43        if (!vaddr)
  44                return -ENOMEM;
  45
  46        if (userbuf) {
  47                if (copy_to_user(buf, vaddr + offset, csize)) {
  48                        iounmap(vaddr);
  49                        return -EFAULT;
  50                }
  51        } else {
  52                memcpy(buf, vaddr + offset, csize);
  53        }
  54
  55        iounmap(vaddr);
  56        return csize;
  57}
  58