PetaLinux新特性，可以指定Linux configuration。Linux configuration文件要放在Linux代码的目录arch/arm64/configs里。使用petalinux-config配置时，指定文件名就可以，不用指定目录。
所以最好一起用Linux configuration和Linux external source。
UG1144的说明如下：
Added Linux Configuration
Added a new menu confi g, petalinux-configuration → Linux configuration , to specify the Linux
defconfig.
如果Linux configuration文件不在目录arch/arm64/configs里，会出现以下错误。
|#####################################################################################################################################################| Time: 0:00:02
Sstate summary: Wanted 3 Found 2 Missed 1 Current 102 (66% match, 99% complete)
NOTE: Executing Tasks
ERROR: linux-xlnx-5.10+gitAUTOINC+568989d441-r0 do_kernel_metadata: A KBUILD_DEFCONFIG '/proj/zcu106/v212/zcu106-bsp-peta/project-spec/xilinx_peta_obj1787_defconfig' was specified, but not present in the source tree (/proj/zcu106/v212/zcu106-bsp-peta/build/tmp/work-shared/zynqmp-generic/kernel-source/arch/arm64/configs/)
ERROR: linux-xlnx-5.10+gitAUTOINC+568989d441-r0 do_kernel_metadata: Execution of '/proj/zcu106/v212/zcu106-bsp-peta/build/tmp/work/zynqmp_generic-xilinx-linux/linux-xlnx/5.10+gitAUTOINC+568989d441-r0/temp/run.do_kernel_metadata.23353' failed with exit code 1:
WARNING: exit code 1 from a shell command.
ERROR: Logfile of failure stored in: /proj/zcu106/v212/zcu106-bsp-peta/build/tmp/work/zynqmp_generic-xilinx-linux/linux-xlnx/5.10+gitAUTOINC+568989d441-r0/temp/log.do_kernel_metadata.23353
ERROR: Task (/proj/zcu106/v212/zcu106-bsp-peta/components/yocto/layers/meta-xilinx/meta-xilinx-bsp/recipes-kernel/linux/linux-xlnx_2021.2.bb:do_kernel_metadata) failed with exit code '1'
NOTE: Tasks Summary: Attempted 470 tasks of which 463 didn't need to be rerun and 1 failed.