linux/include/linux/crash_dump.h
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   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/proc_fs.h>
   7#include <linux/elf.h>
   8
   9#define ELFCORE_ADDR_MAX        (-1ULL)
  10#define ELFCORE_ADDR_ERR        (-2ULL)
  11
  12extern unsigned long long elfcorehdr_addr;
  13extern unsigned long long elfcorehdr_size;
  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/*
  25 * Architecture code can redefine this if there are any special checks
  26 * needed for 64-bit ELF vmcores. In case of 32-bit only architecture,
  27 * this can be set to zero.
  28 */
  29#ifndef vmcore_elf64_check_arch
  30#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  31#endif
  32
  33/*
  34 * is_kdump_kernel() checks whether this kernel is booting after a panic of
  35 * previous kernel or not. This is determined by checking if previous kernel
  36 * has passed the elf core header address on command line.
  37 *
  38 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
  39 * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
  40 * previous kernel.
  41 */
  42
  43static inline int is_kdump_kernel(void)
  44{
  45        return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
  46}
  47
  48/* is_vmcore_usable() checks if the kernel is booting after a panic and
  49 * the vmcore region is usable.
  50 *
  51 * This makes use of the fact that due to alignment -2ULL is not
  52 * a valid pointer, much in the vain of IS_ERR(), except
  53 * dealing directly with an unsigned long long rather than a pointer.
  54 */
  55
  56static inline int is_vmcore_usable(void)
  57{
  58        return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  59}
  60
  61/* vmcore_unusable() marks the vmcore as unusable,
  62 * without disturbing the logic of is_kdump_kernel()
  63 */
  64
  65static inline void vmcore_unusable(void)
  66{
  67        if (is_kdump_kernel())
  68                elfcorehdr_addr = ELFCORE_ADDR_ERR;
  69}
  70
  71#define HAVE_OLDMEM_PFN_IS_RAM 1
  72extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
  73extern void unregister_oldmem_pfn_is_ram(void);
  74
  75#else /* !CONFIG_CRASH_DUMP */
  76static inline int is_kdump_kernel(void) { return 0; }
  77#endif /* CONFIG_CRASH_DUMP */
  78
  79extern unsigned long saved_max_pfn;
  80#endif /* LINUX_CRASHDUMP_H */
  81
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