LXR linux/arch/x86/kernel/crash_dump

   1/*
   2 *      Memory preserving reboot related code.
   3 *
   4 *      Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
   5 *      Copyright (C) IBM Corporation, 2004. All rights reserved
   6 */
   7
   8#include <linux/errno.h>
   9#include <linux/crash_dump.h>
  10#include <linux/uaccess.h>
  11#include <linux/io.h>
  12
  13/* Stores the physical address of elf header of crash image. */
  14unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
  15
  16/**
  17 * copy_oldmem_page - copy one page from "oldmem"
  18 * @pfn: page frame number to be copied
  19 * @buf: target memory address for the copy; this can be in kernel address
  20 *      space or user address space (see @userbuf)
  21 * @csize: number of bytes to copy
  22 * @offset: offset in bytes into the page (based on pfn) to begin the copy
  23 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
  24 *      otherwise @buf is in kernel address space, use memcpy().
  25 *
  26 * Copy a page from "oldmem". For this page, there is no pte mapped
  27 * in the current kernel. We stitch up a pte, similar to kmap_atomic.
  28 */
  29ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
  30                size_t csize, unsigned long offset, int userbuf)
  31{
  32        void  *vaddr;
  33
  34        if (!csize)
  35                return 0;
  36
  37        vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
  38        if (!vaddr)
  39                return -ENOMEM;
  40
  41        if (userbuf) {
  42                if (copy_to_user(buf, vaddr + offset, csize)) {
  43                        iounmap(vaddr);
  44                        return -EFAULT;
  45                }
  46        } else
  47                memcpy(buf, vaddr + offset, csize);
  48
  49        iounmap(vaddr);
  50        return csize;
  51}
  52