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 /*
  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
  42 static 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
  55 static 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
  64 static inline void vmcore_unusable(void)
  65 {
  66         if (is_kdump_kernel())
  67                 elfcorehdr_addr = ELFCORE_ADDR_ERR;
  68 }
  69 #else /* !CONFIG_CRASH_DUMP */
  70 static inline int is_kdump_kernel(void) { return 0; }
  71 #endif /* CONFIG_CRASH_DUMP */
  72
  73 extern unsigned long saved_max_pfn;
  74 #endif /* LINUX_CRASHDUMP_H */