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/proc_fs.h>
   7 #include <linux/elf.h>
   8
   9 #define ELFCORE_ADDR_MAX        (-1ULL)
  10 #define ELFCORE_ADDR_ERR        (-2ULL)
  11
  12 extern unsigned long long elfcorehdr_addr;
  13 extern unsigned long long elfcorehdr_size;
  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 /*
  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
  43 static 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
  56 static 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
  65 static 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
  72 extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
  73 extern void unregister_oldmem_pfn_is_ram(void);
  74
  75 #else /* !CONFIG_CRASH_DUMP */
  76 static inline int is_kdump_kernel(void) { return 0; }
  77 #endif /* CONFIG_CRASH_DUMP */
  78
  79 extern unsigned long saved_max_pfn;
  80 #endif /* LINUX_CRASHDUMP_H */