安装基本工具

因为我这里不是用官方提供的虚拟机，用的是ubuntu20.4，所以需要先安装必要的工具：

sudo apt -y install make git gcc g++ bison flex libncurses5-dev libssl-dev libelf-dev u-boot-tools

sudo apt -y install cmake tree build-essential tcl-dev automake libtool

复制交叉工具链

复制toolchain-loongarch64-linux-gnu-gcc8-host-x86_64-2022-07-18.tar.xz到虚拟机

复制内核源码

复制u-boot源码

解压交叉编译工具、u-boot、内核源码

1、安装工具链的过程其实就是把压缩包解压到/opt目录下：

sudo tar -xf toolchain-loongarch64-linux-gnu-gcc8-host-x86_64-2022-07-18.tar.xz -C /opt/

2、编译u-boot,因为要先编译u-boot后才能有mkimage工具，这样才能打包uImange
设置交叉工具链等环境

lugl@lugl-virtual-machine:~/loonson/u-boot-2022.04-2k500-src-rel2.0.0-e5c962c-build.20221208111218/u-boot-2022.04-2k500-cbd-src$ source ./set_env.sh 
====>setup env for LoongArch..

lugl@lugl-virtual-machine:~/loonson/u-boot-2022.04-2k500-src-rel2.0.0-e5c962c-build.20221208111218/u-boot-2022.04-2k500-cbd-src$ make loongson_2k500_mini_dp_defconfig
#
# configuration written to .config
#
lugl@lugl-virtual-machine:~/loonson/u-boot-2022.04-2k500-src-rel2.0.0-e5c962c-build.20221208111218/u-boot-2022.04-2k500-cbd-src$ make
......
BJCOPY spl/u-boot-spl-nodtb.bin
mkdir -p spl/dts/
  FDTGREP spl/dts/dt-spl.dtb
  COPY    spl/u-boot-spl.dtb
  CAT     spl/u-boot-spl-dtb.bin
  COPY    spl/u-boot-spl.bin
  SYM     spl/u-boot-spl.sym
  MKIMAGE u-boot.img
  COPY    u-boot.dtb
  MKIMAGE u-boot-dtb.img
  CAT     u-boot-with-spl.bin
  CFGCHK  u-boot.cfg
  OFCHK   .config

到这里编译出了u-boot

把mkimage复制到/usr/bin/目录下

ugl@lugl-virtual-machine:~/loonson/u-boot-2022.04-2k500-src-rel2.0.0-e5c962c-build.20221208111218/u-boot-2022.04-2k500-cbd-src/tools$ sudo cp mkimage /usr/bin/

编译内核

进入内核源码下：

lugl@lugl-virtual-machine:~/loonson/linux-5.10-2k500-src-81224fa-build.20221101081146/linux-5.10-2k500-cbd-src$ source ./set_env.sh
====>setup env for LoongArch...
lugl@lugl-virtual-machine:~/loonson/linux-5.10-2k500-src-81224fa-build.20221101081146/linux-5.10-2k500-cbd-src$ make loongson_2k500_defconfig
#
# No change to .config
#
lugl@lugl-virtual-machine:~/loonson/linux-5.10-2k500-src-81224fa-build.20221101081146/linux-5.10-2k500-cbd-src$ make loongson_2k500_defconfig
#
# No change to .config
#
lugl@lugl-virtual-machine:~/loonson/linux-5.10-2k500-src-81224fa-build.20221101081146/linux-5.10-2k500-cbd-src$ make uImage

如果不复制mkimage到指定目录则会报如下错误：

ugl@lugl-virtual-machine:~/loonson/linux-5.10-2k500-src-81224fa-build.20221101081146/linux-5.10-2k500-cbd-src$ make uImage
  CALL    scripts/checksyscalls.sh
  CALL    scripts/atomic/check-atomics.sh
  DESCEND  objtool
  CC      arch/loongarch/vdso/vgettimeofday.o
  LD      arch/loongarch/vdso/vdso.so.dbg
  VDSOSYM include/generated/vdso-offsets.h
  CHK     include/generated/compile.h
  CC      arch/loongarch/kernel/vdso.o
  AR      arch/loongarch/kernel/built-in.a
  CC      arch/loongarch/vdso/vgettimeofday.o
  LD      arch/loongarch/vdso/vdso.so.dbg
  OBJCOPY arch/loongarch/vdso/vdso.so
  AS      arch/loongarch/vdso/vdso.o
  AR      arch/loongarch/vdso/built-in.a
  AR      arch/loongarch/built-in.a
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
  AR      init/built-in.a
  LD      vmlinux.o
  MODPOST vmlinux.symvers
  MODINFO modules.builtin.modinfo
  GEN     modules.builtin
  LD      .tmp_vmlinux.kallsyms1
  KSYMS   .tmp_vmlinux.kallsyms1.S
  AS      .tmp_vmlinux.kallsyms1.S
  LD      .tmp_vmlinux.kallsyms2
  KSYMS   .tmp_vmlinux.kallsyms2.S
  AS      .tmp_vmlinux.kallsyms2.S
  LD      vmlinux
  SORTTAB vmlinux
  SYSMAP  System.map
  OBJCOPY arch/loongarch/boot/vmlinux.bin
  GZIP    arch/loongarch/boot/vmlinux.bin.gz
  UIMAGE  arch/loongarch/boot/uImage.gz

Invalid architecture, supported are:
	alpha            Alpha
	arc              ARC
	arm              ARM
	arm64            AArch64
	avr32            AVR32
	blackfin         Blackfin
	ia64             IA64
	invalid          Invalid ARCH
	m68k             M68K
	microblaze       MicroBlaze
	mips             MIPS
	mips64           MIPS 64 Bit
	nds32            NDS32
	nios2            NIOS II
	or1k             OpenRISC 1000
	powerpc          PowerPC
	riscv            RISC-V
	s390             IBM S390
	sandbox          Sandbox
	sh               SuperH
	sparc            SPARC
	sparc64          SPARC 64 Bit
	x86              Intel x86
	x86_64           AMD x86_64
	xtensa           Xtensa

Error: Invalid architecture
Usage: /usr/bin/mkimage -l image
          -l ==> list image header information
       /usr/bin/mkimage [-x] -A arch -O os -T type -C comp -a addr -e ep -n name -d data_file[:data_file...] image
          -A ==> set architecture to 'arch'
          -O ==> set operating system to 'os'
          -T ==> set image type to 'type'
          -C ==> set compression type 'comp'
          -a ==> set load address to 'addr' (hex)
          -e ==> set entry point to 'ep' (hex)
          -n ==> set image name to 'name'
          -d ==> use image data from 'datafile'
          -x ==> set XIP (execute in place)
       /usr/bin/mkimage [-D dtc_options] [-f fit-image.its|-f auto|-F] [-b <dtb> [-b <dtb>]] [-E] [-B size] [-i <ramdisk.cpio.gz>] fit-image
           <dtb> file is used with -f auto, it may occur multiple times.
          -D => set all options for device tree compiler
          -f => input filename for FIT source
          -i => input filename for ramdisk file
          -E => place data outside of the FIT structure
          -B => align size in hex for FIT structure and header
Signing / verified boot options: [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r] [-N engine]
          -k => set directory containing private keys
          -K => write public keys to this .dtb file
          -G => use this signing key (in lieu of -k)
          -c => add comment in signature node
          -F => re-sign existing FIT image
          -p => place external data at a static position
          -r => mark keys used as 'required' in dtb
          -N => openssl engine to use for signing
       /usr/bin/mkimage -V ==> print version information and exit
Use '-T list' to see a list of available image types
make[1]: *** [arch/loongarch/boot/Makefile:80: arch/loongarch/boot/uImage.gz] Error 1
make: *** [arch/loongarch/Makefile:158: uImage] Error 2

复制好后，就会成功得内核：

lugl@lugl-virtual-machine:~/loonson/linux-5.10-2k500-src-81224fa-build.20221101081146/linux-5.10-2k500-cbd-src$ make uImage
  CALL    scripts/checksyscalls.sh
  CALL    scripts/atomic/check-atomics.sh
  DESCEND  objtool
  CC      arch/loongarch/vdso/vgettimeofday.o
  LD      arch/loongarch/vdso/vdso.so.dbg
  VDSOSYM include/generated/vdso-offsets.h
  CHK     include/generated/compile.h
  CC      arch/loongarch/kernel/vdso.o
  AR      arch/loongarch/kernel/built-in.a
  CC      arch/loongarch/vdso/vgettimeofday.o
  LD      arch/loongarch/vdso/vdso.so.dbg
  OBJCOPY arch/loongarch/vdso/vdso.so
  AS      arch/loongarch/vdso/vdso.o
  AR      arch/loongarch/vdso/built-in.a
  AR      arch/loongarch/built-in.a
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
  AR      init/built-in.a
  LD      vmlinux.o
  MODPOST vmlinux.symvers
  MODINFO modules.builtin.modinfo
  GEN     modules.builtin
  LD      .tmp_vmlinux.kallsyms1
  KSYMS   .tmp_vmlinux.kallsyms1.S
  AS      .tmp_vmlinux.kallsyms1.S
  LD      .tmp_vmlinux.kallsyms2
  KSYMS   .tmp_vmlinux.kallsyms2.S
  AS      .tmp_vmlinux.kallsyms2.S
  LD      vmlinux
  SORTTAB vmlinux
  SYSMAP  System.map
  OBJCOPY arch/loongarch/boot/vmlinux.bin
  GZIP    arch/loongarch/boot/vmlinux.bin.gz
  UIMAGE  arch/loongarch/boot/uImage.gz
Image Name:   Linux-5.10.0.lsgd
Created:      Tue Jan  3 19:58:50 2023
Image Type:   LoongArch Linux Kernel Image (gzip compressed)
Data Size:    7779209 Bytes = 7596.88 KiB = 7.42 MiB
Load Address: 00200000
Entry Point:  00c9b78c
  Image arch/loongarch/boot/uImage is ready

到此龙芯2k0500的内核编译到此就成功了。