// SPDX-License-Identifier: GPL-2.0-only#include <linux/kernel.h>#include <linux/crash_dump.h>#include <linux/init.h>#include <linux/errno.h>#include <linux/export.h> /* * If we have booted due to a crash, max_pfn will be a very low value. We need * to know the amount of memory that the previous kernel used. */unsigned long saved_max_pfn; /* * stores the physical address of elf header of crash image * * Note: elfcorehdr_addr is not just limited to vmcore. It is also used by * is_kdump_kernel() to determine if we are booting after a panic. Hence put * it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE. */unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;EXPORT_SYMBOL_GPL(elfcorehdr_addr); /* * stores the size of elf header of crash image */unsigned long long elfcorehdr_size; /* * elfcorehdr= specifies the location of elf core header stored by the crashed * kernel. This option will be passed by kexec loader to the capture kernel. * * Syntax: elfcorehdr=[size[KMG]@]offset[KMG] */static int __init setup_elfcorehdr(char *arg){	char *end;	if (!arg)		return -EINVAL;	elfcorehdr_addr = memparse(arg, &end);	if (*end == '@') {		elfcorehdr_size = elfcorehdr_addr;		elfcorehdr_addr = memparse(end + 1, &end);	}	return end > arg ? 0 : -EINVAL;}early_param("elfcorehdr", setup_elfcorehdr);