LXR linux/include/linux/crash

   1#ifndef LINUX_CRASH_DUMP_H
   2#define LINUX_CRASH_DUMP_H
   3
   4#ifdef CONFIG_CRASH_DUMP
   5#include <linux/kexec.h>
   6#include <linux/device.h>
   7#include <linux/proc_fs.h>
   8
   9#define ELFCORE_ADDR_MAX        (-1ULL)
  10#define ELFCORE_ADDR_ERR        (-2ULL)
  11
  12extern unsigned long long elfcorehdr_addr;
  13
  14extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
  15                                                unsigned long, int);
  16
  17/* Architecture code defines this if there are other possible ELF
  18 * machine types, e.g. on bi-arch capable hardware. */
  19#ifndef vmcore_elf_check_arch_cross
  20#define vmcore_elf_check_arch_cross(x) 0
  21#endif
  22
  23#define vmcore_elf_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  24
  25/*
  26 * is_kdump_kernel() checks whether this kernel is booting after a panic of
  27 * previous kernel or not. This is determined by checking if previous kernel
  28 * has passed the elf core header address on command line.
  29 *
  30 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
  31 * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
  32 * previous kernel.
  33 */
  34
  35static inline int is_kdump_kernel(void)
  36{
  37        return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
  38}
  39
  40/* is_vmcore_usable() checks if the kernel is booting after a panic and
  41 * the vmcore region is usable.
  42 *
  43 * This makes use of the fact that due to alignment -2ULL is not
  44 * a valid pointer, much in the vain of IS_ERR(), except
  45 * dealing directly with an unsigned long long rather than a pointer.
  46 */
  47
  48static inline int is_vmcore_usable(void)
  49{
  50        return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  51}
  52
  53/* vmcore_unusable() marks the vmcore as unusable,
  54 * without disturbing the logic of is_kdump_kernel()
  55 */
  56
  57static inline void vmcore_unusable(void)
  58{
  59        if (is_kdump_kernel())
  60                elfcorehdr_addr = ELFCORE_ADDR_ERR;
  61}
  62#else /* !CONFIG_CRASH_DUMP */
  63static inline int is_kdump_kernel(void) { return 0; }
  64#endif /* CONFIG_CRASH_DUMP */
  65
  66extern unsigned long saved_max_pfn;
  67#endif /* LINUX_CRASHDUMP_H */
  68