kernel.mk: Support kernels that use LTO
Google added support for LTO + CFI in the Pixel 3 kernel, which requires
not only Clang but a couple of additional binaries, namely llvm-ar and
llvm-dis for IR generation. Google expects these binaries to be in PATH
according to their definitions and the build.config.common file:
https://android.googlesource.com/kernel/msm/+/android-9.0.0_r0.31/Makefile#637
https://android.googlesource.com/kernel/msm/+/android-9.0.0_r0.31/build.config.common
However, kernel.mk does not add the LLVM bin directory to PATH so the
build fails because the binaries can't be found. We could add LLVM_AR
and LLVM_DIS to the make commands like CC and CROSS_COMPILE; however,
adding the bin directory to PATH is a more sustainable solution as
Google might require new binaries in the future.
Additionally, LTO needs access to the LLVMgold library so it needs to be
available in LD_LIBRARY_PATH.
Add a PATH_OVERRIDE variable that will set up PATH and LD_LIBRARY_PATH
with the bin and lib64 folders from the requested LLVM toolchain
respectively when building with Clang. This won't affect kernels that
don't use LTO like Wahoo.
Change-Id: Ib16fa0d3180de2f96accb2f7648b07a017f8f98b
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index 7a674ee..54812a9 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -178,8 +178,9 @@
else ifeq ($(KERNEL_ARCH),x86)
KERNEL_CLANG_TRIPLE ?= CLANG_TRIPLE=x86_64-linux-gnu-
endif
+ PATH_OVERRIDE := PATH=$(TARGET_KERNEL_CLANG_PATH):$$PATH LD_LIBRARY_PATH=$(BUILD_TOP)/prebuilts/clang/host/$(HOST_OS)-x86/$(KERNEL_CLANG_VERSION)/lib64:$$LD_LIBRARY_PATH
ifeq ($(KERNEL_CC),)
- KERNEL_CC := CC="$(CCACHE_BIN) $(TARGET_KERNEL_CLANG_PATH)/clang"
+ KERNEL_CC := CC="$(CCACHE_BIN) clang"
endif
endif
@@ -196,17 +197,17 @@
$(KERNEL_CONFIG): $(KERNEL_DEFCONFIG_SRC) $(KERNEL_ADDITIONAL_CONFIG_OUT)
@echo "Building Kernel Config"
$(hide) mkdir -p $(KERNEL_OUT)
- $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) VARIANT_DEFCONFIG=$(VARIANT_DEFCONFIG) SELINUX_DEFCONFIG=$(SELINUX_DEFCONFIG) $(KERNEL_DEFCONFIG)
+ $(PATH_OVERRIDE) $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) VARIANT_DEFCONFIG=$(VARIANT_DEFCONFIG) SELINUX_DEFCONFIG=$(SELINUX_DEFCONFIG) $(KERNEL_DEFCONFIG)
$(hide) if [ ! -z "$(KERNEL_CONFIG_OVERRIDE)" ]; then \
echo "Overriding kernel config with '$(KERNEL_CONFIG_OVERRIDE)'"; \
echo $(KERNEL_CONFIG_OVERRIDE) >> $(KERNEL_OUT)/.config; \
- $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) oldconfig; fi
+ $(PATH_OVERRIDE) $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) oldconfig; fi
# Create defconfig build artifact
- $(hide) $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) savedefconfig
+ $(hide) $(PATH_OVERRIDE) $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) savedefconfig
$(hide) if [ ! -z "$(KERNEL_ADDITIONAL_CONFIG)" ]; then \
echo "Using additional config '$(KERNEL_ADDITIONAL_CONFIG)'"; \
$(KERNEL_SRC)/scripts/kconfig/merge_config.sh -m -O $(KERNEL_OUT) $(KERNEL_OUT)/.config $(KERNEL_SRC)/arch/$(KERNEL_ARCH)/configs/$(KERNEL_ADDITIONAL_CONFIG); \
- $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) KCONFIG_ALLCONFIG=$(KERNEL_OUT)/.config alldefconfig; fi
+ $(PATH_OVERRIDE) $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) KCONFIG_ALLCONFIG=$(KERNEL_OUT)/.config alldefconfig; fi
.PHONY: TARGET_KERNEL_BINARIES
TARGET_KERNEL_BINARIES: $(KERNEL_CONFIG)
@@ -214,21 +215,21 @@
$(hide) rm -rf $(KERNEL_MODULES_OUT)
$(hide) mkdir -p $(KERNEL_MODULES_OUT)
$(hide) rm -rf $(KERNEL_DEPMOD_STAGING_DIR)
- $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(BOARD_KERNEL_IMAGE_NAME)
+ $(PATH_OVERRIDE) $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(BOARD_KERNEL_IMAGE_NAME)
$(hide) if grep -q '^CONFIG_OF=y' $(KERNEL_CONFIG); then \
echo "Building DTBs"; \
- $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) dtbs; \
+ $(PATH_OVERRIDE) $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) dtbs; \
fi
$(hide) if grep -q '^CONFIG_MODULES=y' $(KERNEL_CONFIG); then \
echo "Building Kernel Modules"; \
- $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) modules; \
+ $(PATH_OVERRIDE) $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) modules; \
fi
.PHONY: INSTALLED_KERNEL_MODULES
INSTALLED_KERNEL_MODULES: depmod-host
$(hide) if grep -q '^CONFIG_MODULES=y' $(KERNEL_CONFIG); then \
echo "Installing Kernel Modules"; \
- $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) INSTALL_MOD_PATH=../../$(KERNEL_MODULES_INSTALL) modules_install && \
+ $(PATH_OVERRIDE) $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) INSTALL_MOD_PATH=../../$(KERNEL_MODULES_INSTALL) modules_install && \
mofile=$$(find $(KERNEL_MODULES_OUT) -type f -name modules.order) && \
mpath=$$(dirname $$mofile) && \
for f in $$(find $$mpath/kernel -type f -name '*.ko'); do \
@@ -249,29 +250,29 @@
.PHONY: kerneltags
kerneltags: $(KERNEL_CONFIG)
$(hide) mkdir -p $(KERNEL_OUT)
- $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) tags
+ $(PATH_OVERRIDE) $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) tags
.PHONY: kernelsavedefconfig alldefconfig
kernelsavedefconfig:
$(hide) mkdir -p $(KERNEL_OUT)
- $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(KERNEL_DEFCONFIG)
+ $(PATH_OVERRIDE) $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(KERNEL_DEFCONFIG)
env KCONFIG_NOTIMESTAMP=true \
- $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) savedefconfig
+ $(PATH_OVERRIDE) $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) savedefconfig
cp $(KERNEL_OUT)/defconfig $(KERNEL_DEFCONFIG_SRC)
alldefconfig:
$(hide) mkdir -p $(KERNEL_OUT)
env KCONFIG_NOTIMESTAMP=true \
- $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) alldefconfig
+ $(PATH_OVERRIDE) $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) alldefconfig
endif # FULL_KERNEL_BUILD
TARGET_PREBUILT_DTBO = $(PRODUCT_OUT)/dtbo/arch/$(KERNEL_ARCH)/boot/dtbo.img
$(TARGET_PREBUILT_DTBO): $(AVBTOOL)
echo -e ${CL_GRN}"Building DTBO.img"${CL_RST}
- $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(PRODUCT_OUT)/dtbo ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(KERNEL_DEFCONFIG)
- $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(PRODUCT_OUT)/dtbo ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) dtbo.img
+ $(PATH_OVERRIDE) $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(PRODUCT_OUT)/dtbo ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(KERNEL_DEFCONFIG)
+ $(PATH_OVERRIDE) $(MAKE) $(KERNEL_MAKE_FLAGS) -C $(KERNEL_SRC) O=$(PRODUCT_OUT)/dtbo ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) dtbo.img
$(AVBTOOL) add_hash_footer \
--image $@ \
--partition_size $(BOARD_DTBOIMG_PARTITION_SIZE) \