kernel/crash_dump.c

   1 #include <linux/kernel.h>
   2 #include <linux/crash_dump.h>
   3 #include <linux/init.h>
   4 #include <linux/errno.h>
   5 #include <linux/module.h>
   6
   7 /*
   8  * If we have booted due to a crash, max_pfn will be a very low value. We need
   9  * to know the amount of memory that the previous kernel used.
  10  */
  11 unsigned long saved_max_pfn;
  12
  13 /*
  14  * stores the physical address of elf header of crash image
  15  *
  16  * Note: elfcorehdr_addr is not just limited to vmcore. It is also used by
  17  * is_kdump_kernel() to determine if we are booting after a panic. Hence put
  18  * it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE.
  19  */
  20 unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
  21
  22 /*
  23  * stores the size of elf header of crash image
  24  */
  25 unsigned long long elfcorehdr_size;
  26
  27 /*
  28  * elfcorehdr= specifies the location of elf core header stored by the crashed
  29  * kernel. This option will be passed by kexec loader to the capture kernel.
  30  *
  31  * Syntax: elfcorehdr=[size[KMG]@]offset[KMG]
  32  */
  33 static int __init setup_elfcorehdr(char *arg)
  34 {
  35         char *end;
  36         if (!arg)
  37                 return -EINVAL;
  38         elfcorehdr_addr = memparse(arg, &end);
  39         if (*end == '@') {
  40                 elfcorehdr_size = elfcorehdr_addr;
  41                 elfcorehdr_addr = memparse(end + 1, &end);
  42         }
  43         return end > arg ? 0 : -EINVAL;
  44 }
  45 early_param("elfcorehdr", setup_elfcorehdr);