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b1992c3772
Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:
src := $(obj)
When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.
This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.
To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.
Going forward, the variables used in Makefiles will have the following
meanings:
$(obj) - directory in the object tree
$(src) - directory in the source tree (changed by this commit)
$(objtree) - the top of the kernel object tree
$(srctree) - the top of the kernel source tree
Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
251 lines
8.7 KiB
Makefile
251 lines
8.7 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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HID_SAMPLES_PATH ?= $(abspath $(src))
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TOOLS_PATH := $(HID_SAMPLES_PATH)/../../tools
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pound := \#
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# List of programs to build
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tprogs-y += hid_mouse
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tprogs-y += hid_surface_dial
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# Libbpf dependencies
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LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf
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LIBBPF_OUTPUT = $(abspath $(HID_SAMPLES_PATH))/libbpf
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LIBBPF_DESTDIR = $(LIBBPF_OUTPUT)
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LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include
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LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a
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EXTRA_HEADERS := hid_bpf_attach.h
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EXTRA_BPF_HEADERS := hid_bpf_helpers.h
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hid_mouse-objs := hid_mouse.o
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hid_surface_dial-objs := hid_surface_dial.o
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# Tell kbuild to always build the programs
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always-y := $(tprogs-y)
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ifeq ($(ARCH), arm)
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# Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux
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# headers when arm instruction set identification is requested.
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ARM_ARCH_SELECTOR := $(filter -D__LINUX_ARM_ARCH__%, $(KBUILD_CFLAGS))
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BPF_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR)
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TPROGS_CFLAGS += $(ARM_ARCH_SELECTOR)
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endif
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ifeq ($(ARCH), mips)
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TPROGS_CFLAGS += -D__SANE_USERSPACE_TYPES__
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ifdef CONFIG_MACH_LOONGSON64
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BPF_EXTRA_CFLAGS += -I$(srctree)/arch/mips/include/asm/mach-loongson64
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BPF_EXTRA_CFLAGS += -I$(srctree)/arch/mips/include/asm/mach-generic
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endif
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endif
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TPROGS_CFLAGS += -Wall -O2
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TPROGS_CFLAGS += -Wmissing-prototypes
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TPROGS_CFLAGS += -Wstrict-prototypes
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TPROGS_CFLAGS += -I$(objtree)/usr/include
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TPROGS_CFLAGS += -I$(LIBBPF_INCLUDE)
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TPROGS_CFLAGS += -I$(srctree)/tools/include
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ifdef SYSROOT
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TPROGS_CFLAGS += --sysroot=$(SYSROOT)
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TPROGS_LDFLAGS := -L$(SYSROOT)/usr/lib
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endif
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TPROGS_LDLIBS += $(LIBBPF) -lelf -lz
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# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
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# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
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LLC ?= llc
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CLANG ?= clang
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OPT ?= opt
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LLVM_DIS ?= llvm-dis
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LLVM_OBJCOPY ?= llvm-objcopy
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LLVM_READELF ?= llvm-readelf
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BTF_PAHOLE ?= pahole
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# Detect that we're cross compiling and use the cross compiler
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ifdef CROSS_COMPILE
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CLANG_ARCH_ARGS = --target=$(notdir $(CROSS_COMPILE:%-=%))
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endif
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# Don't evaluate probes and warnings if we need to run make recursively
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ifneq ($(src),)
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HDR_PROBE := $(shell printf "$(pound)include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \
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$(CC) $(TPROGS_CFLAGS) $(TPROGS_LDFLAGS) -x c - \
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-o /dev/null 2>/dev/null && echo okay)
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ifeq ($(HDR_PROBE),)
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$(warning WARNING: Detected possible issues with include path.)
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$(warning WARNING: Please install kernel headers locally (make headers_install).)
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endif
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BTF_LLC_PROBE := $(shell $(LLC) -march=bpf -mattr=help 2>&1 | grep dwarfris)
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BTF_PAHOLE_PROBE := $(shell $(BTF_PAHOLE) --help 2>&1 | grep BTF)
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BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm')
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BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" | \
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$(CLANG) --target=bpf -O2 -g -c -x c - -o ./llvm_btf_verify.o; \
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$(LLVM_READELF) -S ./llvm_btf_verify.o | grep BTF; \
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/bin/rm -f ./llvm_btf_verify.o)
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BPF_EXTRA_CFLAGS += -fno-stack-protector
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ifneq ($(BTF_LLVM_PROBE),)
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BPF_EXTRA_CFLAGS += -g
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else
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ifneq ($(and $(BTF_LLC_PROBE),$(BTF_PAHOLE_PROBE),$(BTF_OBJCOPY_PROBE)),)
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BPF_EXTRA_CFLAGS += -g
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LLC_FLAGS += -mattr=dwarfris
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DWARF2BTF = y
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endif
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endif
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endif
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# Trick to allow make to be run from this directory
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all:
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$(MAKE) -C ../../ M=$(CURDIR) HID_SAMPLES_PATH=$(CURDIR)
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clean:
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$(MAKE) -C ../../ M=$(CURDIR) clean
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@find $(CURDIR) -type f -name '*~' -delete
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@$(RM) -r $(CURDIR)/libbpf $(CURDIR)/bpftool
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$(LIBBPF): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT)
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# Fix up variables inherited from Kbuild that tools/ build system won't like
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$(MAKE) -C $(LIBBPF_SRC) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \
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LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(HID_SAMPLES_PATH)/../../ \
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O= OUTPUT=$(LIBBPF_OUTPUT)/ DESTDIR=$(LIBBPF_DESTDIR) prefix= \
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$@ install_headers
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BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool
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BPFTOOL_OUTPUT := $(abspath $(HID_SAMPLES_PATH))/bpftool
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BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool
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$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT)
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$(MAKE) -C $(BPFTOOLDIR) srctree=$(HID_SAMPLES_PATH)/../../ \
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OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap
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$(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT):
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$(call msg,MKDIR,$@)
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$(Q)mkdir -p $@
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FORCE:
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# Verify LLVM compiler tools are available and bpf target is supported by llc
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.PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC)
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verify_cmds: $(CLANG) $(LLC)
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@for TOOL in $^ ; do \
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if ! (which -- "$${TOOL}" > /dev/null 2>&1); then \
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echo "*** ERROR: Cannot find LLVM tool $${TOOL}" ;\
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exit 1; \
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else true; fi; \
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done
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verify_target_bpf: verify_cmds
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@if ! (${LLC} -march=bpf -mattr=help > /dev/null 2>&1); then \
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echo "*** ERROR: LLVM (${LLC}) does not support 'bpf' target" ;\
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echo " NOTICE: LLVM version >= 3.7.1 required" ;\
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exit 2; \
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else true; fi
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$(HID_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF)
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$(src)/*.c: verify_target_bpf $(LIBBPF)
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libbpf_hdrs: $(LIBBPF)
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.PHONY: libbpf_hdrs
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$(obj)/hid_mouse.o: $(obj)/hid_mouse.skel.h
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$(obj)/hid_surface_dial.o: $(obj)/hid_surface_dial.skel.h
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-include $(HID_SAMPLES_PATH)/Makefile.target
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VMLINUX_BTF_PATHS ?= $(abspath $(if $(O),$(O)/vmlinux)) \
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$(abspath $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)) \
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$(abspath ./vmlinux)
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VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
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$(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
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ifeq ($(VMLINUX_H),)
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ifeq ($(VMLINUX_BTF),)
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$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)",\
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build the kernel or set VMLINUX_BTF or VMLINUX_H variable)
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endif
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$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
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else
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$(Q)cp "$(VMLINUX_H)" $@
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endif
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clean-files += vmlinux.h
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# Get Clang's default includes on this system, as opposed to those seen by
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# '--target=bpf'. This fixes "missing" files on some architectures/distros,
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# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
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#
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# Use '-idirafter': Don't interfere with include mechanics except where the
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# build would have failed anyways.
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define get_sys_includes
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$(shell $(1) -v -E - </dev/null 2>&1 \
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| sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \
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$(shell $(1) -dM -E - </dev/null | grep '#define __riscv_xlen ' | sed 's/#define /-D/' | sed 's/ /=/')
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endef
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CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
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EXTRA_BPF_HEADERS_SRC := $(addprefix $(src)/,$(EXTRA_BPF_HEADERS))
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$(obj)/%.bpf.o: $(src)/%.bpf.c $(EXTRA_BPF_HEADERS_SRC) $(obj)/vmlinux.h
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@echo " CLANG-BPF " $@
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$(Q)$(CLANG) -g -O2 --target=bpf -D__TARGET_ARCH_$(SRCARCH) \
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-Wno-compare-distinct-pointer-types -I$(srctree)/include \
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-I$(srctree)/samples/bpf -I$(srctree)/tools/include \
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-I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES) \
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-c $(filter %.bpf.c,$^) -o $@
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LINKED_SKELS := hid_mouse.skel.h hid_surface_dial.skel.h
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clean-files += $(LINKED_SKELS)
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hid_mouse.skel.h-deps := hid_mouse.bpf.o hid_bpf_attach.bpf.o
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hid_surface_dial.skel.h-deps := hid_surface_dial.bpf.o hid_bpf_attach.bpf.o
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LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))
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BPF_SRCS_LINKED := $(notdir $(wildcard $(src)/*.bpf.c))
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BPF_OBJS_LINKED := $(patsubst %.bpf.c,$(obj)/%.bpf.o, $(BPF_SRCS_LINKED))
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BPF_SKELS_LINKED := $(addprefix $(obj)/,$(LINKED_SKELS))
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$(BPF_SKELS_LINKED): $(BPF_OBJS_LINKED) $(BPFTOOL)
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@echo " BPF GEN-OBJ " $(@:.skel.h=)
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$(Q)$(BPFTOOL) gen object $(@:.skel.h=.lbpf.o) $(addprefix $(obj)/,$($(@F)-deps))
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@echo " BPF GEN-SKEL" $(@:.skel.h=)
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$(Q)$(BPFTOOL) gen skeleton $(@:.skel.h=.lbpf.o) name $(notdir $(@:.skel.h=)) > $@
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# asm/sysreg.h - inline assembly used by it is incompatible with llvm.
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# But, there is no easy way to fix it, so just exclude it since it is
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# useless for BPF samples.
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# below we use long chain of commands, clang | opt | llvm-dis | llc,
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# to generate final object file. 'clang' compiles the source into IR
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# with native target, e.g., x64, arm64, etc. 'opt' does bpf CORE IR builtin
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# processing (llvm12) and IR optimizations. 'llvm-dis' converts
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# 'opt' output to IR, and finally 'llc' generates bpf byte code.
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$(obj)/%.o: $(src)/%.c
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@echo " CLANG-bpf " $@
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$(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(BPF_EXTRA_CFLAGS) \
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-I$(obj) -I$(srctree)/tools/testing/selftests/bpf/ \
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-I$(LIBBPF_INCLUDE) \
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-D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \
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-D__TARGET_ARCH_$(SRCARCH) -Wno-compare-distinct-pointer-types \
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-Wno-gnu-variable-sized-type-not-at-end \
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-Wno-address-of-packed-member -Wno-tautological-compare \
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-Wno-unknown-warning-option $(CLANG_ARCH_ARGS) \
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-fno-asynchronous-unwind-tables \
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-I$(srctree)/samples/hid/ \
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-O2 -emit-llvm -Xclang -disable-llvm-passes -c $< -o - | \
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$(OPT) -O2 -mtriple=bpf-pc-linux | $(LLVM_DIS) | \
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$(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@
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ifeq ($(DWARF2BTF),y)
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$(BTF_PAHOLE) -J $@
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endif
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