1 #include <linux/kernel.h>
2 #include <linux/crash_dump.h>
3 #include <linux/init.h>
4 #include <linux/errno.h>
5 #include <linux/export.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 EXPORT_SYMBOL_GPL(elfcorehdr_addr);
22 
23 /*
24  * stores the size of elf header of crash image
25  */
26 unsigned long long elfcorehdr_size;
27 
28 /*
29  * elfcorehdr= specifies the location of elf core header stored by the crashed
30  * kernel. This option will be passed by kexec loader to the capture kernel.
31  *
32  * Syntax: elfcorehdr=[size[KMG]@]offset[KMG]
33  */
setup_elfcorehdr(char * arg)34 static int __init setup_elfcorehdr(char *arg)
35 {
36 	char *end;
37 	if (!arg)
38 		return -EINVAL;
39 	elfcorehdr_addr = memparse(arg, &end);
40 	if (*end == '@') {
41 		elfcorehdr_size = elfcorehdr_addr;
42 		elfcorehdr_addr = memparse(end + 1, &end);
43 	}
44 	return end > arg ? 0 : -EINVAL;
45 }
46 early_param("elfcorehdr", setup_elfcorehdr);
47