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