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In kdump kernel, /proc/vmcore is an elf file mapping the crashed kernel's old memory content. Its elf header is constructed in 1st kernel and passed to kdump kernel via elfcorehdr_addr. Config CRASH_DUMP enables the code of 1st kernel's old memory accessing in different architectures. Currently, config FA_DUMP has dependency on CRASH_DUMP because fadump needs access global variable 'elfcorehdr_addr' to judge if it's in kdump kernel within function is_kdump_kernel(). In the current kernel/crash_dump.c, variable 'elfcorehdr_addr' is defined, and function setup_elfcorehdr() used to parse kernel parameter to fetch the passed value of elfcorehdr_addr. Only for accessing elfcorehdr_addr, FA_DUMP really doesn't have to depends on CRASH_DUMP. To remove the dependency of FA_DUMP on CRASH_DUMP to avoid confusion, rename kernel/crash_dump.c to kernel/elfcorehdr.c, and build it when CONFIG_VMCORE_INFO is ebabled. With this, FA_DUMP doesn't need to depend on CRASH_DUMP. [bhe@redhat.com: power/fadump: make FA_DUMP select CRASH_DUMP] Link: https://lkml.kernel.org/r/Zb8D1ASrgX0qVm9z@MiWiFi-R3L-srv Link: https://lkml.kernel.org/r/20240124051254.67105-4-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Pingfan Liu <piliu@redhat.com> Cc: Klara Modin <klarasmodin@gmail.com> Cc: Michael Kelley <mhklinux@outlook.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
42 lines
1.1 KiB
C
42 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#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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* 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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