openwrt/include/bpf.mk
Felix Fietkau a537d06c72 bpf-headers: add a package with kernel headers for ebpf
In order to genererate suitable kernel headers, a 5.10 kernel tree is
prepared with a default config for mips. The arch is forced to mips in
order to avoid issues with inline asm on various architectures in a way
that doesn't involve relying on the host toolchain/headers.
It also has the advantage of supporting both endian types

Signed-off-by: Felix Fietkau <nbd@nbd.name>
2021-11-01 16:39:09 +01:00

66 lines
2.4 KiB
Makefile

ifneq ($(CONFIG_BPF_TOOLCHAIN_HOST),)
BPF_TOOLCHAIN_HOST_PATH:=$(call qstrip,$(CONFIG_BPF_TOOLCHAIN_HOST_PATH))
ifneq ($(BPF_TOOLCHAIN_HOST_PATH),)
BPF_PATH:=$(BPF_TOOLCHAIN_HOST_PATH)/bin:$(PATH)
else
BPF_PATH:=$(BPF_PATH)
endif
CLANG:=$(firstword $(shell PATH='$(BPF_PATH)' which clang clang-13 clang-12 clang-11))
LLVM_VER:=$(subst clang,,$(notdir $(CLANG)))
else
CLANG:=$(STAGING_DIR_HOST)/bin/clang
LLVM_VER:=
endif
LLVM_PATH:=$(dir $(CLANG))
LLVM_LLC:=$(LLVM_PATH)/llc$(LLVM_VER)
LLVM_DIS:=$(LLVM_PATH)/llvm-dis$(LLVM_VER)
LLVM_OPT:=$(LLVM_PATH)/opt$(LLVM_VER)
LLVM_STRIP:=$(LLVM_PATH)/llvm-strip$(LLVM_VER)
BPF_KARCH:=mips
BPF_ARCH:=mips$(if $(CONFIG_BIG_ENDIAN),,el)
BPF_HEADERS_DIR:=$(STAGING_DIR)/bpf-headers
BPF_KERNEL_INCLUDE := \
-nostdinc -isystem $(TOOLCHAIN_DIR)/include \
-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include \
-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include/asm/mach-generic \
-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include/generated \
-I$(BPF_HEADERS_DIR)/include \
-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include/uapi \
-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include/generated/uapi \
-I$(BPF_HEADERS_DIR)/include/uapi \
-I$(BPF_HEADERS_DIR)/include/generated/uapi \
-I$(BPF_HEADERS_DIR)/tools/lib \
-I$(BPF_HEADERS_DIR)/tools/testing/selftests \
-I$(BPF_HEADERS_DIR)/samples/bpf \
-include linux/kconfig.h -include asm_goto_workaround.h
BPF_CFLAGS := \
$(BPF_KERNEL_INCLUDE) -I$(PKG_BUILD_DIR) \
-D__KERNEL__ -D__BPF_TRACING__ \
-D__TARGET_ARCH_${BPF_KARCH} \
-m$(if $(CONFIG_BIG_ENDIAN),big,little)-endian \
-fno-stack-protector -Wall \
-Wno-unused-value -Wno-pointer-sign \
-Wno-compare-distinct-pointer-types \
-Wno-gnu-variable-sized-type-not-at-end \
-Wno-address-of-packed-member -Wno-tautological-compare \
-Wno-unknown-warning-option \
-fno-asynchronous-unwind-tables \
-Wno-uninitialized -Wno-unused-variable \
-Wno-unused-label \
-O2 -emit-llvm -Xclang -disable-llvm-passes
define CompileBPF
$(CLANG) -g -target $(BPF_ARCH)-linux-gnu $(BPF_CFLAGS) $(2) \
-c $(1) -o $(patsubst %.c,%.bc,$(1))
$(LLVM_OPT) -O2 -mtriple=bpf-pc-linux < $(patsubst %.c,%.bc,$(1)) > $(patsubst %.c,%.opt,$(1))
$(LLVM_DIS) < $(patsubst %.c,%.opt,$(1)) > $(patsubst %.c,%.S,$(1))
$(LLVM_LLC) -march=bpf -filetype=obj -o $(patsubst %.c,%.o,$(1)) < $(patsubst %.c,%.S,$(1))
$(LLVM_STRIP) --strip-debug $(patsubst %.c,%.o,$(1))
endef