reproduce (this is a W=1 build):
        git remote add openeuler https://gitee.com/openeuler/kernel.git
        git fetch --no-tags openeuler OLK-6.6
        git checkout 221e2e8bdbb851a519df0bac5a44298dae2b4612

        # install loongarch cross compiling tool for clang build
        # apt-get install binutils-loongarch-linux-gnu
        # clang-22 might not be officially released. Try a lower version if installation fails.
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # apt-get install sparse
        # sparse version: v0.6.4-71-g610d841d

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=loongarch olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=loongarch SHELL=/bin/bash arch/loongarch/kernel/ crypto/ drivers/base/regmap/ drivers/bcma/ drivers/block/ drivers/bluetooth/ drivers/char/ drivers/clk/ drivers/counter/ drivers/crypto/aspeed/ drivers/crypto/cavium/nitrox/ drivers/crypto/hisilicon/ drivers/crypto/qce/ drivers/cxl/ drivers/dma/qcom/ drivers/firmware/arm_scmi/ drivers/firmware/broadcom/ drivers/firmware/efi/ drivers/fpga/ drivers/gpu/drm/amd/amdgpu/ drivers/gpu/drm/arm/ drivers/gpu/drm/bridge/ drivers/gpu/drm/etnaviv/ drivers/gpu/drm/i2c/ drivers/gpu/drm/msm/ drivers/gpu/drm/panel/ drivers/gpu/drm/tidss/ drivers/gpu/drm/tiny/ drivers/gpu/drm/xlnx/ drivers/hsi/clients/ drivers/hwmon/ drivers/hwtracing/stm/ drivers/i2c/busses/ drivers/iio/adc/ drivers/iio/chemical/ drivers/iio/common/scmi_sensors/ drivers/iio/dac/ drivers/iio/gyro/ drivers/iio/imu/ drivers/iio/pressure/ drivers/iio/temperature/ drivers/input/keyboard/ drivers/input/misc/ drivers/input/rmi4/ drivers/input/touchscreen/ drivers/leds/ drivers/message/fusion/ drivers/mfd/ drivers/misc/ drivers/most/ drivers/nvdimm/ drivers/nvme/host/ drivers/nvmem/ drivers/phy/mediatek/ drivers/phy/qualcomm/ drivers/phy/ti/ drivers/phy/xilinx/ drivers/power/supply/ drivers/pwm/ drivers/regulator/ drivers/rpmsg/ drivers/scsi/ drivers/soc/qcom/ drivers/spi/ drivers/spmi/ drivers/ssb/ drivers/staging/greybus/ drivers/staging/iio/addac/ drivers/staging/most/i2c/ drivers/staging/vc04_services/ drivers/target/ drivers/tty/ drivers/ufs/core/ drivers/ufs/host/ drivers/vdpa/vdpa_user/ drivers/vfio/pci/ drivers/vhost/ drivers/watchdog/ fs/adfs/ fs/btrfs/ fs/cramfs/ fs/f2fs/ fs/fat/ fs/gfs2/ fs/hfs/ fs/jfs/ fs/romfs/ fs/ufs/ kernel/locking/ kernel/trace/ net/8021q/ net/bluetooth/ net/bridge/ net/can/ net/mpls/ net/packet/ net/phonet/ net/sched/ sound/core/ sound/drivers/ sound/hda/ sound/i2c/other/ sound/pci/