#ifndef LINUX_CRASH_DUMP_H
  #define LINUX_CRASH_DUMP_H
  
  #ifdef CONFIG_CRASH_DUMP
  #include <linux/kexec.h>

  #include <linux/device.h>
  #include <linux/proc_fs.h>

  #define ELFCORE_ADDR_MAX	(-1ULL)

  #define ELFCORE_ADDR_ERR	(-2ULL)

  extern unsigned long long elfcorehdr_addr;

  extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
  						unsigned long, int);

  /* Architecture code defines this if there are other possible ELF
   * machine types, e.g. on bi-arch capable hardware. */
  #ifndef vmcore_elf_check_arch_cross
  #define vmcore_elf_check_arch_cross(x) 0
  #endif

  /*
   * Architecture code can redefine this if there are any special checks
   * needed for 64-bit ELF vmcores. In case of 32-bit only architecture,
   * this can be set to zero.
   */
  #ifndef vmcore_elf64_check_arch
  #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  #endif

  /*
   * is_kdump_kernel() checks whether this kernel is booting after a panic of
   * previous kernel or not. This is determined by checking if previous kernel
   * has passed the elf core header address on command line.
   *
   * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
   * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
   * previous kernel.
   */

  static inline int is_kdump_kernel(void)
  {
  	return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
  }

  
  /* is_vmcore_usable() checks if the kernel is booting after a panic and
   * the vmcore region is usable.
   *
   * This makes use of the fact that due to alignment -2ULL is not
   * a valid pointer, much in the vain of IS_ERR(), except
   * dealing directly with an unsigned long long rather than a pointer.
   */
  
  static inline int is_vmcore_usable(void)
  {
  	return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  }
  
  /* vmcore_unusable() marks the vmcore as unusable,
   * without disturbing the logic of is_kdump_kernel()
   */
  
  static inline void vmcore_unusable(void)
  {
  	if (is_kdump_kernel())
  		elfcorehdr_addr = ELFCORE_ADDR_ERR;
  }

  
  #define HAVE_OLDMEM_PFN_IS_RAM 1
  extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
  extern void unregister_oldmem_pfn_is_ram(void);

  #else /* !CONFIG_CRASH_DUMP */
  static inline int is_kdump_kernel(void) { return 0; }

  #endif /* CONFIG_CRASH_DUMP */

  
  extern unsigned long saved_max_pfn;

  #endif /* LINUX_CRASHDUMP_H */