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/device.h>
   7 #include <linux/proc_fs.h>
   8
   9 #define ELFCORE_ADDR_MAX        (-1ULL)
  10 #define ELFCORE_ADDR_ERR        (-2ULL)
  11
  12 extern unsigned long long elfcorehdr_addr;
  13
  14 extern 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
  35 static 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
  48 static 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
  57 static inline void vmcore_unusable(void)
  58 {
  59         if (is_kdump_kernel())
  60                 elfcorehdr_addr = ELFCORE_ADDR_ERR;
  61 }
  62 #else /* !CONFIG_CRASH_DUMP */
  63 static inline int is_kdump_kernel(void) { return 0; }
  64 #endif /* CONFIG_CRASH_DUMP */
  65
  66 extern unsigned long saved_max_pfn;
  67 #endif /* LINUX_CRASHDUMP_H */