Root/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/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 */
11unsigned 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 */
20unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
21
22/*
23 * stores the size of elf header of crash image
24 */
25unsigned 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 */
33static 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}
45early_param("elfcorehdr", setup_elfcorehdr);
46

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