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/*
  24 * Architecture code can redefine this if there are any special checks
  25 * needed for 64-bit ELF vmcores. In case of 32-bit only architecture,
  26 * this can be set to zero.
  27 */
  28#ifndef vmcore_elf64_check_arch
  29#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  30#endif
  31
  32/*
  33 * is_kdump_kernel() checks whether this kernel is booting after a panic of
  34 * previous kernel or not. This is determined by checking if previous kernel
  35 * has passed the elf core header address on command line.
  36 *
  37 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
  38 * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
  39 * previous kernel.
  40 */
  41
  42static inline int is_kdump_kernel(void)
  43{
  44        return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
  45}
  46
  47/* is_vmcore_usable() checks if the kernel is booting after a panic and
  48 * the vmcore region is usable.
  49 *
  50 * This makes use of the fact that due to alignment -2ULL is not
  51 * a valid pointer, much in the vain of IS_ERR(), except
  52 * dealing directly with an unsigned long long rather than a pointer.
  53 */
  54
  55static inline int is_vmcore_usable(void)
  56{
  57        return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  58}
  59
  60/* vmcore_unusable() marks the vmcore as unusable,
  61 * without disturbing the logic of is_kdump_kernel()
  62 */
  63
  64static inline void vmcore_unusable(void)
  65{
  66        if (is_kdump_kernel())
  67                elfcorehdr_addr = ELFCORE_ADDR_ERR;
  68}
  69#else /* !CONFIG_CRASH_DUMP */
  70static inline int is_kdump_kernel(void) { return 0; }
  71#endif /* CONFIG_CRASH_DUMP */
  72
  73extern unsigned long saved_max_pfn;
  74#endif /* LINUX_CRASHDUMP_H */
  75