[PATCH 0/6] Add kexec_file support for LoongArch

[Youling Tang <youling.tang@linux.dev>]

From: Youling Tang <tangyouling@kylinos.cn>

This patchset implement kexec_file_load() support on LoongArch.

This patch series enables us to load the LoongArch vmlinuz.efi or
vmlinux.efi by specifying its file decriptor, instead of user-filled
buffer via kexec_load() syscall.

To use kexec_file_load() system call, instead of kexec_load(), at kexec
command, '-s' options must be specified. kexec-tools needs to apply the
corresponding patches. These patches can be found in repository [1] and
will be submitted to the kexec-tools community later.

The basic usage of kexec_file is:
1) Load second kernel image:
 # kexec -s -l vmlinuz.efi --initrd=initrd.img --reuse-cmdline

2) Startup second kernel:
 # kexec -e

For kdump:
1) Load capture kernel image:
 # kexec -s -p vmlinuz.efi --initrd=initrd.img --reuse-cmdline

2) Do something to crash, like:
 # echo c > /proc/sysrq-trigger

Link:
[1] https://github.com/tangyouling/kexec-tools/commits/main/

Youling Tang (6):
  LoongArch: Add struct loongarch_image_header for kernel image
  LoongArch: Add kexec_file support
  LoongArch/kexec_file: Add initrd loading
  LoongArch/kexec_file: Add crash dump support
  LoongArch/kexec_file: Add "mem" parameter to limit memory usage of
    kdump kernel
  LoongArch: Enable CONFIG_KEXEC_FILE

 arch/loongarch/Kconfig                     |   8 +
 arch/loongarch/configs/loongson3_defconfig |   1 +
 arch/loongarch/include/asm/image.h         |  58 +++++
 arch/loongarch/include/asm/kexec.h         |  12 ++
 arch/loongarch/kernel/Makefile             |   1 +
 arch/loongarch/kernel/kexec_image.c        | 112 ++++++++++
 arch/loongarch/kernel/machine_kexec.c      |  33 ++-
 arch/loongarch/kernel/machine_kexec_file.c | 234 +++++++++++++++++++++
 8 files changed, 448 insertions(+), 11 deletions(-)
 create mode 100644 arch/loongarch/include/asm/image.h
 create mode 100644 arch/loongarch/kernel/kexec_image.c
 create mode 100644 arch/loongarch/kernel/machine_kexec_file.c

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2.34.1