LXR linux/arch/sh/kernel/crash

   1/*
   2 *      crash_dump.c - 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#include <linux/errno.h>
   8#include <linux/crash_dump.h>
   9#include <linux/io.h>
  10#include <linux/uaccess.h>
  11
  12/**
  13 * copy_oldmem_page - copy one page from "oldmem"
  14 * @pfn: page frame number to be copied
  15 * @buf: target memory address for the copy; this can be in kernel address
  16 *      space or user address space (see @userbuf)
  17 * @csize: number of bytes to copy
  18 * @offset: offset in bytes into the page (based on pfn) to begin the copy
  19 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
  20 *      otherwise @buf is in kernel address space, use memcpy().
  21 *
  22 * Copy a page from "oldmem". For this page, there is no pte mapped
  23 * in the current kernel. We stitch up a pte, similar to kmap_atomic.
  24 */
  25ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
  26                               size_t csize, unsigned long offset, int userbuf)
  27{
  28        void  *vaddr;
  29
  30        if (!csize)
  31                return 0;
  32
  33        vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
  34
  35        if (userbuf) {
  36                if (copy_to_user(buf, (vaddr + offset), csize)) {
  37                        iounmap(vaddr);
  38                        return -EFAULT;
  39                }
  40        } else
  41        memcpy(buf, (vaddr + offset), csize);
  42
  43        iounmap(vaddr);
  44        return csize;
  45}
  46