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linux-next/kernel/crash_dump.c
Amir Vadai b3292e88e3 crash_dump: Make is_kdump_kernel() accessible from modules
In order to make is_kdump_kernel() accessible from modules, need to
make elfcorehdr_addr exported.
This was rejected in the past [1] because reset_devices was prefered in
that context (reseting the device in kdump kernel), but now there are
some network drivers that need to reduce memory usage when loaded from
a kdump kernel.  And in that context, is_kdump_kernel() suits better.

[1] - https://lkml.org/lkml/2011/1/27/341

CC: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-25 15:42:19 -07:00

47 lines
1.3 KiB
C

#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);