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 extern const struct file_operations proc_vmcore_operations;
  18 extern struct proc_dir_entry *proc_vmcore;
  19
  20 /* Architecture code defines this if there are other possible ELF
  21  * machine types, e.g. on bi-arch capable hardware. */
  22 #ifndef vmcore_elf_check_arch_cross
  23 #define vmcore_elf_check_arch_cross(x) 0
  24 #endif
  25
  26 #define vmcore_elf_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
  27
  28 /*
  29  * is_kdump_kernel() checks whether this kernel is booting after a panic of
  30  * previous kernel or not. This is determined by checking if previous kernel
  31  * has passed the elf core header address on command line.
  32  *
  33  * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
  34  * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
  35  * previous kernel.
  36  */
  37
  38 static inline int is_kdump_kernel(void)
  39 {
  40         return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
  41 }
  42
  43 /* is_vmcore_usable() checks if the kernel is booting after a panic and
  44  * the vmcore region is usable.
  45  *
  46  * This makes use of the fact that due to alignment -2ULL is not
  47  * a valid pointer, much in the vain of IS_ERR(), except
  48  * dealing directly with an unsigned long long rather than a pointer.
  49  */
  50
  51 static inline int is_vmcore_usable(void)
  52 {
  53         return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
  54 }
  55
  56 /* vmcore_unusable() marks the vmcore as unusable,
  57  * without disturbing the logic of is_kdump_kernel()
  58  */
  59
  60 static inline void vmcore_unusable(void)
  61 {
  62         if (is_kdump_kernel())
  63                 elfcorehdr_addr = ELFCORE_ADDR_ERR;
  64 }
  65 #else /* !CONFIG_CRASH_DUMP */
  66 static inline int is_kdump_kernel(void) { return 0; }
  67 #endif /* CONFIG_CRASH_DUMP */
  68
  69 extern unsigned long saved_max_pfn;
  70 #endif /* LINUX_CRASHDUMP_H */