include/linux/crash_dump.h

   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
  13 extern unsigned long long elfcorehdr_addr;
  14
  15 extern 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
  36 static 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
  49 static 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
  58 static inline void vmcore_unusable(void)
  59 {
  60         if (is_kdump_kernel())
  61                 elfcorehdr_addr = ELFCORE_ADDR_ERR;
  62 }
  63 #else /* !CONFIG_CRASH_DUMP */
  64 static inline int is_kdump_kernel(void) { return 0; }
  65 #endif /* CONFIG_CRASH_DUMP */
  66
  67 extern unsigned long saved_max_pfn;
  68 #endif /* LINUX_CRASHDUMP_H */