enable kernel build with external obj output

Signed-off-by: yuanbo <yuanbo@huawei.com>

build_kernel.sh

@@ -23,5 +23,5 @@ set -e
 pushd ${1}
 ./kernel_module_build.sh ${2} ${4} ${5} ${6} ${7} ${8}
 mkdir -p ${3}
-cp ${2}/kernel/src_tmp/${8}/arch/arm/boot/uImage ${3}/uImage
+cp ${2}/kernel/OBJ/${8}/arch/arm/boot/uImage ${3}/uImage
 popd

kernel.mk

@@ -17,6 +17,7 @@
 PRODUCT_NAME=$(TARGET_PRODUCT)
 OHOS_BUILD_HOME := $(realpath $(shell pwd)/../../../)
 KERNEL_SRC_TMP_PATH := $(OUT_DIR)/kernel/${KERNEL_VERSION}
+KERNEL_OBJ_TMP_PATH := $(OUT_DIR)/kernel/OBJ/${KERNEL_VERSION}
 ifeq ($(BUILD_TYPE), standard)
     OHOS_BUILD_HOME := $(OHOS_ROOT_PATH)
     BOOT_IMAGE_PATH = $(OHOS_BUILD_HOME)/device/hisilicon/hispark_taurus/prebuilts
@@ -68,6 +69,8 @@ SMALL_PATCH_FILE := $(DEVICE_PATCH_DIR)/$(DEVICE_NAME)_$(BUILD_TYPE).patch
 KERNEL_IMAGE_FILE := $(KERNEL_SRC_TMP_PATH)/arch/arm/boot/uImage
 DEFCONFIG_FILE := $(DEVICE_NAME)_$(BUILD_TYPE)_defconfig
 
+export KBUILD_OUTPUT=$(KERNEL_OBJ_TMP_PATH)
+
 $(KERNEL_IMAGE_FILE):
 	$(hide) echo "build kernel..."
 	$(hide) rm -rf $(KERNEL_SRC_TMP_PATH);mkdir -p $(KERNEL_SRC_TMP_PATH);cp -arfL $(KERNEL_SRC_PATH)/* $(KERNEL_SRC_TMP_PATH)/

kernel_module_build.sh

@@ -37,11 +37,12 @@ elif [ $2 == "standard" ];then
     LINUX_KERNEL_OUT=${OUT_DIR}/kernel/src_tmp/${KERNEL_VERSION}
     CLANG_BASE_PATH=$3
 fi
+LINUX_KERNEL_OBJ_OUT=${OUT_DIR}/kernel/OBJ/${KERNEL_VERSION}
 
 export OHOS_ROOT_PATH=$(pwd)/../../..
 export PRODUCT_PATH=$4
 
-LINUX_KERNEL_UIMAGE_FILE=${LINUX_KERNEL_OUT}/arch/arm/boot/uImage
+LINUX_KERNEL_UIMAGE_FILE=${LINUX_KERNEL_OBJ_OUT}/arch/arm/boot/uImage
 
 make -f kernel.mk