linux-yocto/samples/hid/Makefile

SPDX-License-Identifier: GPL-2.0

HID_SAMPLES_PATH ?= $(abspath $(srctree)/$(src)) TOOLS_PATH := $(HID_SAMPLES_PATH)/../../tools

pound := #

List of programs to build

tprogs-y += hid_mouse tprogs-y += hid_surface_dial

Libbpf dependencies

LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf LIBBPF_OUTPUT = $(abspath $(HID_SAMPLES_PATH))/libbpf LIBBPF_DESTDIR = $(LIBBPF_OUTPUT) LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a

EXTRA_HEADERS := hid_bpf_attach.h EXTRA_BPF_HEADERS := hid_bpf_helpers.h

hid_mouse-objs := hid_mouse.o hid_surface_dial-objs := hid_surface_dial.o

Tell kbuild to always build the programs

always-y := $(tprogs-y)

ifeq ($(ARCH), arm)

Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux

headers when arm instruction set identification is requested.

ARM_ARCH_SELECTOR := $(filter -D__LINUX_ARM_ARCH__%, $(KBUILD_CFLAGS)) BPF_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR) TPROGS_CFLAGS += $(ARM_ARCH_SELECTOR) endif

ifeq ($(ARCH), mips) TPROGS_CFLAGS += -D__SANE_USERSPACE_TYPES__ ifdef CONFIG_MACH_LOONGSON64 BPF_EXTRA_CFLAGS += -I$(srctree)/arch/mips/include/asm/mach-loongson64 BPF_EXTRA_CFLAGS += -I$(srctree)/arch/mips/include/asm/mach-generic endif endif

TPROGS_CFLAGS += -Wall -O2 TPROGS_CFLAGS += -Wmissing-prototypes TPROGS_CFLAGS += -Wstrict-prototypes

TPROGS_CFLAGS += -I$(objtree)/usr/include TPROGS_CFLAGS += -I$(LIBBPF_INCLUDE) TPROGS_CFLAGS += -I$(srctree)/tools/include

ifdef SYSROOT TPROGS_CFLAGS += --sysroot=$(SYSROOT) TPROGS_LDFLAGS := -L$(SYSROOT)/usr/lib endif

TPROGS_LDLIBS += $(LIBBPF) -lelf -lz

Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:

make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang

LLC ?= llc CLANG ?= clang OPT ?= opt LLVM_DIS ?= llvm-dis LLVM_OBJCOPY ?= llvm-objcopy LLVM_READELF ?= llvm-readelf BTF_PAHOLE ?= pahole

Detect that we're cross compiling and use the cross compiler

ifdef CROSS_COMPILE CLANG_ARCH_ARGS = --target=$(notdir $(CROSS_COMPILE:%-=%)) endif

Don't evaluate probes and warnings if we need to run make recursively

ifneq ($(src),) HDR_PROBE := $(shell printf "$(pound)include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" |
$(CC) $(TPROGS_CFLAGS) $(TPROGS_LDFLAGS) -x c -
-o /dev/null 2>/dev/null && echo okay)

ifeq ($(HDR_PROBE),) $(warning WARNING: Detected possible issues with include path.) $(warning WARNING: Please install kernel headers locally (make headers_install).) endif

BTF_LLC_PROBE := $(shell $(LLC) -march=bpf -mattr=help 2>&1 | grep dwarfris) BTF_PAHOLE_PROBE := $(shell $(BTF_PAHOLE) --help 2>&1 | grep BTF) BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm') BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" |
$(CLANG) --target=bpf -O2 -g -c -x c - -o ./llvm_btf_verify.o;
$(LLVM_READELF) -S ./llvm_btf_verify.o | grep BTF;
/bin/rm -f ./llvm_btf_verify.o)

BPF_EXTRA_CFLAGS += -fno-stack-protector ifneq ($(BTF_LLVM_PROBE),) BPF_EXTRA_CFLAGS += -g else ifneq ($(and $(BTF_LLC_PROBE),$(BTF_PAHOLE_PROBE),$(BTF_OBJCOPY_PROBE)),) BPF_EXTRA_CFLAGS += -g LLC_FLAGS += -mattr=dwarfris DWARF2BTF = y endif endif endif

Trick to allow make to be run from this directory

all: $(MAKE) -C ../../ M=$(CURDIR) HID_SAMPLES_PATH=$(CURDIR)

clean: $(MAKE) -C ../../ M=$(CURDIR) clean @find $(CURDIR) -type f -name '*~' -delete @$(RM) -r $(CURDIR)/libbpf $(CURDIR)/bpftool

$(LIBBPF): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT)

Fix up variables inherited from Kbuild that tools/ build system won't like

$(MAKE) -C $(LIBBPF_SRC) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \
	LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(HID_SAMPLES_PATH)/../../ \
	O= OUTPUT=$(LIBBPF_OUTPUT)/ DESTDIR=$(LIBBPF_DESTDIR) prefix= \
	$@ install_headers

BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool BPFTOOL_OUTPUT := $(abspath $(HID_SAMPLES_PATH))/bpftool BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool $(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT) $(MAKE) -C $(BPFTOOLDIR) srctree=$(HID_SAMPLES_PATH)/../../
OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap

$(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT): $(call msg,MKDIR,$@) $(Q)mkdir -p $@

FORCE:

Verify LLVM compiler tools are available and bpf target is supported by llc

.PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC)

verify_cmds: $(CLANG) $(LLC) @for TOOL in $^ ; do
if ! (which -- "$${TOOL}" > /dev/null 2>&1); then
echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;
exit 1;
else true; fi;
done

verify_target_bpf: verify_cmds @if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then
echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;
echo " NOTICE: LLVM version >= 3.7.1 required" ;
exit 2;
else true; fi

$(HID_SAMPLES_PATH)/.c: verify_target_bpf $(LIBBPF) $(src)/.c: verify_target_bpf $(LIBBPF)

libbpf_hdrs: $(LIBBPF)

.PHONY: libbpf_hdrs

$(obj)/hid_mouse.o: $(obj)/hid_mouse.skel.h $(obj)/hid_surface_dial.o: $(obj)/hid_surface_dial.skel.h

-include $(HID_SAMPLES_PATH)/Makefile.target

VMLINUX_BTF_PATHS ?= $(abspath $(if $(O),$(O)/vmlinux))
$(abspath $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux))
$(abspath ./vmlinux) VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))

$(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) ifeq ($(VMLINUX_H),) ifeq ($(VMLINUX_BTF),) $(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)",
build the kernel or set VMLINUX_BTF or VMLINUX_H variable) endif $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@ else $(Q)cp "$(VMLINUX_H)" $@ endif

clean-files += vmlinux.h

Get Clang's default includes on this system, as opposed to those seen by

'--target=bpf'. This fixes "missing" files on some architectures/distros,

such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.

Use '-idirafter': Don't interfere with include mechanics except where the

build would have failed anyways.

define get_sys_includes $(shell $(1) -v -E - </dev/null 2>&1
| sed -n '/<...> search starts here:/,/End of search list./{ s| (/.*)|-idirafter \1|p }')
$(shell $(1) -dM -E - </dev/null | grep '#define __riscv_xlen ' | sed 's/#define /-D/' | sed 's/ /=/') endef

CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))

EXTRA_BPF_HEADERS_SRC := $(addprefix $(src)/,$(EXTRA_BPF_HEADERS))

$(obj)/%.bpf.o: $(src)/%.bpf.c $(EXTRA_BPF_HEADERS_SRC) $(obj)/vmlinux.h @echo " CLANG-BPF " $@ $(Q)$(CLANG) -g -O2 --target=bpf -D__TARGET_ARCH_$(SRCARCH)
-Wno-compare-distinct-pointer-types -I$(srctree)/include
-I$(srctree)/samples/bpf -I$(srctree)/tools/include
-I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES)
-c $(filter %.bpf.c,$^) -o $@

LINKED_SKELS := hid_mouse.skel.h hid_surface_dial.skel.h clean-files += $(LINKED_SKELS)

hid_mouse.skel.h-deps := hid_mouse.bpf.o hid_bpf_attach.bpf.o hid_surface_dial.skel.h-deps := hid_surface_dial.bpf.o hid_bpf_attach.bpf.o

LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))

BPF_SRCS_LINKED := $(notdir $(wildcard $(src)/*.bpf.c)) BPF_OBJS_LINKED := $(patsubst %.bpf.c,$(obj)/%.bpf.o, $(BPF_SRCS_LINKED)) BPF_SKELS_LINKED := $(addprefix $(obj)/,$(LINKED_SKELS))

$(BPF_SKELS_LINKED): $(BPF_OBJS_LINKED) $(BPFTOOL) @echo " BPF GEN-OBJ " $(@:.skel.h=) $(Q)$(BPFTOOL) gen object $(@:.skel.h=.lbpf.o) $(addprefix $(obj)/,$($(@F)-deps)) @echo " BPF GEN-SKEL" $(@:.skel.h=) $(Q)$(BPFTOOL) gen skeleton $(@:.skel.h=.lbpf.o) name $(notdir $(@:.skel.h=)) > $@

asm/sysreg.h - inline assembly used by it is incompatible with llvm.

But, there is no easy way to fix it, so just exclude it since it is

useless for BPF samples.

below we use long chain of commands, clang | opt | llvm-dis | llc,

to generate final object file. 'clang' compiles the source into IR

with native target, e.g., x64, arm64, etc. 'opt' does bpf CORE IR builtin

processing (llvm12) and IR optimizations. 'llvm-dis' converts

'opt' output to IR, and finally 'llc' generates bpf byte code.

$(obj)/%.o: $(src)/%.c @echo " CLANG-bpf " $@ $(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(BPF_EXTRA_CFLAGS)
-I$(obj) -I$(srctree)/tools/testing/selftests/bpf/
-I$(LIBBPF_INCLUDE)
-D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign
-D__TARGET_ARCH_$(SRCARCH) -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 $(CLANG_ARCH_ARGS)
-fno-asynchronous-unwind-tables
-I$(srctree)/samples/hid/
-O2 -emit-llvm -Xclang -disable-llvm-passes -c $< -o - |
$(OPT) -O2 -mtriple=bpf-pc-linux | $(LLVM_DIS) |
$(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@ ifeq ($(DWARF2BTF),y) $(BTF_PAHOLE) -J $@ endif