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/smp_lock.h>
   7#include <linux/device.h>
   8#include <linux/proc_fs.h>
   9
  10#define ELFCORE_ADDR_MAX        (-1ULL)
  11#define ELFCORE_ADDR_ERR        (-2ULL)
  12
  13extern unsigned long long elfcorehdr_addr;
  14
  15extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
  16                                                unsigned long, int);
  17
  18/* Architecture code defines this if there are other possible ELF
  19 * machine types, e.g. on bi-arch capable hardware. */
  20#ifndef vmcore_elf_check_arch_cross
  21#define vmcore_elf_check_arch_cross(x) 0
  22#endif
  23
  24#define vmcore_elf_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  25
  26/*
  27 * is_kdump_kernel() checks whether this kernel is booting after a panic of
  28 * previous kernel or not. This is determined by checking if previous kernel
  29 * has passed the elf core header address on command line.
  30 *
  31 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
  32 * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
  33 * previous kernel.
  34 */
  35
  36static inline int is_kdump_kernel(void)
  37{
  38        return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
  39}
  40
  41/* is_vmcore_usable() checks if the kernel is booting after a panic and
  42 * the vmcore region is usable.
  43 *
  44 * This makes use of the fact that due to alignment -2ULL is not
  45 * a valid pointer, much in the vain of IS_ERR(), except
  46 * dealing directly with an unsigned long long rather than a pointer.
  47 */
  48
  49static inline int is_vmcore_usable(void)
  50{
  51        return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  52}
  53
  54/* vmcore_unusable() marks the vmcore as unusable,
  55 * without disturbing the logic of is_kdump_kernel()
  56 */
  57
  58static inline void vmcore_unusable(void)
  59{
  60        if (is_kdump_kernel())
  61                elfcorehdr_addr = ELFCORE_ADDR_ERR;
  62}
  63#else /* !CONFIG_CRASH_DUMP */
  64static inline int is_kdump_kernel(void) { return 0; }
  65#endif /* CONFIG_CRASH_DUMP */
  66
  67extern unsigned long saved_max_pfn;
  68#endif /* LINUX_CRASHDUMP_H */
  69