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 #include <linux/elf.h>
   9
  10 #define ELFCORE_ADDR_MAX        (-1ULL)
  11 #define ELFCORE_ADDR_ERR        (-2ULL)
  12
  13 extern unsigned long long elfcorehdr_addr;
  14 extern unsigned long long elfcorehdr_size;
  15
  16 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
  17                                                 unsigned long, int);
  18
  19 /* Architecture code defines this if there are other possible ELF
  20  * machine types, e.g. on bi-arch capable hardware. */
  21 #ifndef vmcore_elf_check_arch_cross
  22 #define vmcore_elf_check_arch_cross(x) 0
  23 #endif
  24
  25 /*
  26  * Architecture code can redefine this if there are any special checks
  27  * needed for 64-bit ELF vmcores. In case of 32-bit only architecture,
  28  * this can be set to zero.
  29  */
  30 #ifndef vmcore_elf64_check_arch
  31 #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  32 #endif
  33
  34 /*
  35  * is_kdump_kernel() checks whether this kernel is booting after a panic of
  36  * previous kernel or not. This is determined by checking if previous kernel
  37  * has passed the elf core header address on command line.
  38  *
  39  * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
  40  * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
  41  * previous kernel.
  42  */
  43
  44 static inline int is_kdump_kernel(void)
  45 {
  46         return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
  47 }
  48
  49 /* is_vmcore_usable() checks if the kernel is booting after a panic and
  50  * the vmcore region is usable.
  51  *
  52  * This makes use of the fact that due to alignment -2ULL is not
  53  * a valid pointer, much in the vain of IS_ERR(), except
  54  * dealing directly with an unsigned long long rather than a pointer.
  55  */
  56
  57 static inline int is_vmcore_usable(void)
  58 {
  59         return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  60 }
  61
  62 /* vmcore_unusable() marks the vmcore as unusable,
  63  * without disturbing the logic of is_kdump_kernel()
  64  */
  65
  66 static inline void vmcore_unusable(void)
  67 {
  68         if (is_kdump_kernel())
  69                 elfcorehdr_addr = ELFCORE_ADDR_ERR;
  70 }
  71
  72 #define HAVE_OLDMEM_PFN_IS_RAM 1
  73 extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
  74 extern void unregister_oldmem_pfn_is_ram(void);
  75
  76 #else /* !CONFIG_CRASH_DUMP */
  77 static inline int is_kdump_kernel(void) { return 0; }
  78 #endif /* CONFIG_CRASH_DUMP */
  79
  80 extern unsigned long saved_max_pfn;
  81 #endif /* LINUX_CRASHDUMP_H */