arch/arm/kernel/crash_dump.c

   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 /* stores the physical address of elf header of crash image */
  22 unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
  23
  24 /**
  25  * copy_oldmem_page() - copy one page from old kernel memory
  26  * @pfn: page frame number to be copied
  27  * @buf: buffer where the copied page is placed
  28  * @csize: number of bytes to copy
  29  * @offset: offset in bytes into the page
  30  * @userbuf: if set, @buf is int he user address space
  31  *
  32  * This function copies one page from old kernel memory into buffer pointed by
  33  * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
  34  * copied or negative error in case of failure.
  35  */
  36 ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
  37                          size_t csize, unsigned long offset,
  38                          int userbuf)
  39 {
  40         void *vaddr;
  41
  42         if (!csize)
  43                 return 0;
  44
  45         vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
  46         if (!vaddr)
  47                 return -ENOMEM;
  48
  49         if (userbuf) {
  50                 if (copy_to_user(buf, vaddr + offset, csize)) {
  51                         iounmap(vaddr);
  52                         return -EFAULT;
  53                 }
  54         } else {
  55                 memcpy(buf, vaddr + offset, csize);
  56         }
  57
  58         iounmap(vaddr);
  59         return csize;
  60 }