# SPDX-License-Identifier: GPL-2.0 # ========================================================================== # Building # ========================================================================== src := $(obj) PHONY := $(obj)/ $(obj)/: # Init all relevant variables used in kbuild files so # 1) they have correct type # 2) they do not inherit any value from the environment obj-y := obj-m := lib-y := lib-m := always-y := always-m := targets := subdir-y := subdir-m := EXTRA_AFLAGS := EXTRA_CFLAGS := EXTRA_CPPFLAGS := EXTRA_LDFLAGS := asflags-y := ccflags-y := rustflags-y := cppflags-y := ldflags-y := subdir-asflags-y := subdir-ccflags-y := # Read auto.conf if it exists, otherwise ignore -include include/config/auto.conf include $(srctree)/scripts/Kbuild.include include $(srctree)/scripts/Makefile.compiler # The filename Kbuild has precedence over Makefile kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) include $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile) include $(srctree)/scripts/Makefile.lib # Do not include hostprogs rules unless needed. # $(sort ...) is used here to remove duplicated words and excessive spaces. hostprogs := $(sort $(hostprogs)) ifneq ($(hostprogs),) include $(srctree)/scripts/Makefile.host endif # Do not include userprogs rules unless needed. # $(sort ...) is used here to remove duplicated words and excessive spaces. userprogs := $(sort $(userprogs)) ifneq ($(userprogs),) include $(srctree)/scripts/Makefile.userprogs endif ifndef obj $(warning kbuild: Makefile.build is included improperly) endif ifeq ($(need-modorder),) ifneq ($(obj-m),) $(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) $(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) endif endif # =========================================================================== # subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...) subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y))) subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) targets-for-builtin := $(extra-y) ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) targets-for-builtin += $(obj)/lib.a endif ifdef need-builtin targets-for-builtin += $(obj)/built-in.a endif targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \ $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) ifdef need-modorder targets-for-modules += $(obj)/modules.order endif targets += $(targets-for-builtin) $(targets-for-modules) # Linus' kernel sanity checking tool ifeq ($(KBUILD_CHECKSRC),1) quiet_cmd_checksrc = CHECK $< cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< else ifeq ($(KBUILD_CHECKSRC),2) quiet_cmd_force_checksrc = CHECK $< cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< endif ifneq ($(KBUILD_EXTRA_WARN),) cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< endif # Compile C sources (.c) # --------------------------------------------------------------------------- quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< $(obj)/%.s: $(src)/%.c FORCE $(call if_changed_dep,cc_s_c) quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< $(obj)/%.i: $(src)/%.c FORCE $(call if_changed_dep,cpp_i_c) genksyms = scripts/genksyms/genksyms \ $(if $(1), -T $(2)) \ $(if $(KBUILD_PRESERVE), -p) \ -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null) # These mirror gensymtypes_S and co below, keep them in synch. cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ cmd_cc_symtypes_c = $(call cmd_gensymtypes_c,true,$@) >/dev/null $(obj)/%.symtypes : $(src)/%.c FORCE $(call cmd,cc_symtypes_c) # LLVM assembly # Generate .ll files from .c quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $< $(obj)/%.ll: $(src)/%.c FORCE $(call if_changed_dep,cc_ll_c) # C (.c) files # The C file is compiled and updated dependency information is generated. # (See cmd_cc_o_c + relevant part of rule_cc_o_c) is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) # When a module consists of a single object, there is no reason to keep LLVM IR. # Make $(LD) covert LLVM IR to ELF here. ifdef CONFIG_LTO_CLANG cmd_ld_single_m = $(if $(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@) endif quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \ $(cmd_ld_single_m) \ $(cmd_objtool) ifdef CONFIG_MODVERSIONS # When module versioning is enabled the following steps are executed: # o compile a .o from .c # o if .o doesn't contain a __ksymtab version, i.e. does # not export symbols, it's done. # o otherwise, we calculate symbol versions using the good old # genksyms on the preprocessed source and dump them into the .cmd file. # o modpost will extract versions from that file and create *.c files that will # be compiled and linked to the kernel and/or modules. gen_symversions = \ if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ >> $(dot-target).cmd; \ fi cmd_gen_symversions_c = $(call gen_symversions,c) endif ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT # compiler will not generate __mcount_loc use recordmcount or recordmcount.pl ifdef BUILD_C_RECORDMCOUNT ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") RECORDMCOUNT_FLAGS = -w endif # Due to recursion, we must skip empty.o. # The empty.o file is created in the make process in order to determine # the target endianness and word size. It is made before all other C # files, including recordmcount. sub_cmd_record_mcount = \ if [ $(@) != "scripts/mod/empty.o" ]; then \ $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ fi; recordmcount_source := $(srctree)/scripts/recordmcount.c \ $(srctree)/scripts/recordmcount.h else sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ "$(if $(CONFIG_64BIT),64,32)" \ "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ "$(if $(part-of-module),1,0)" "$(@)"; recordmcount_source := $(srctree)/scripts/recordmcount.pl endif # BUILD_C_RECORDMCOUNT cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ $(sub_cmd_record_mcount)) endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y) $(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) ifdef CONFIG_TRIM_UNUSED_KSYMS cmd_gen_ksymdeps = \ $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd endif cmd_check_local_export = $(srctree)/scripts/check-local-export $@ define rule_cc_o_c $(call cmd_and_fixdep,cc_o_c) $(call cmd,gen_ksymdeps) $(call cmd,check_local_export) $(call cmd,checksrc) $(call cmd,checkdoc) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_c) $(call cmd,record_mcount) endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) $(call cmd,gen_ksymdeps) $(call cmd,check_local_export) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_S) endef # Built-in and composite module parts $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call if_changed_rule,cc_o_c) $(call cmd,force_checksrc) # To make this rule robust against "Argument list too long" error, # ensure to add $(obj)/ prefix by a shell command. cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ $(obj)/%.mod: FORCE $(call if_changed,mod) # List module undefined symbols cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@ $(obj)/%.usyms: $(obj)/%.o FORCE $(call if_changed,undefined_syms) quiet_cmd_cc_lst_c = MKLST $@ cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ System.map $(OBJDUMP) > $@ $(obj)/%.lst: $(src)/%.c FORCE $(call if_changed_dep,cc_lst_c) # Compile Rust sources (.rs) # --------------------------------------------------------------------------- rust_allowed_features := core_ffi_c rust_common_cmd = \ RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ -Zallow-features=$(rust_allowed_features) \ -Zcrate-attr=no_std \ -Zcrate-attr='feature($(rust_allowed_features))' \ --extern alloc --extern kernel \ --crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \ --crate-name $(basename $(notdir $@)) rust_handle_depfile = \ mv $(obj)/$(basename $(notdir $@)).d $(depfile); \ sed -i '/^\#/d' $(depfile) # `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit # will be used. We explicitly request `-Ccodegen-units=1` in any case, and # the compiler shows a warning if it is not 1. However, if we ever stop # requesting it explicitly and we start using some other `--emit` that does not # imply it (and for which codegen is performed), then we would be out of sync, # i.e. the outputs we would get for the different single targets (e.g. `.ll`) # would not match each other. quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ cmd_rustc_o_rs = \ $(rust_common_cmd) --emit=dep-info,obj $<; \ $(rust_handle_depfile) $(obj)/%.o: $(src)/%.rs FORCE $(call if_changed_dep,rustc_o_rs) quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ cmd_rustc_rsi_rs = \ $(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \ command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \ $(rust_handle_depfile) $(obj)/%.rsi: $(src)/%.rs FORCE $(call if_changed_dep,rustc_rsi_rs) quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ cmd_rustc_s_rs = \ $(rust_common_cmd) --emit=dep-info,asm $<; \ $(rust_handle_depfile) $(obj)/%.s: $(src)/%.rs FORCE $(call if_changed_dep,rustc_s_rs) quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ cmd_rustc_ll_rs = \ $(rust_common_cmd) --emit=dep-info,llvm-ir $<; \ $(rust_handle_depfile) $(obj)/%.ll: $(src)/%.rs FORCE $(call if_changed_dep,rustc_ll_rs) # Compile assembler sources (.S) # --------------------------------------------------------------------------- # .S file exports must have their C prototypes defined in asm/asm-prototypes.h # or a file that it includes, in order to get versioned symbols. We build a # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from # the .S file (with trailing ';'), and run genksyms on that, to extract vers. # # This is convoluted. The .S file must first be preprocessed to run guards and # expand names, then the resulting exports must be constructed into plain # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed # to make the genksyms input. # # These mirror gensymtypes_c and co above, keep them in synch. cmd_gensymtypes_S = \ { echo "\#include " ; \ echo "\#include " ; \ $(CPP) $(a_flags) $< | \ grep "\<___EXPORT_SYMBOL\>" | \ sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null $(obj)/%.symtypes : $(src)/%.S FORCE $(call cmd,cc_symtypes_S) quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< $(obj)/%.s: $(src)/%.S FORCE $(call if_changed_dep,cpp_s_S) quiet_cmd_as_o_S = AS $(quiet_modtag) $@ cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool) ifdef CONFIG_ASM_MODVERSIONS # versioning matches the C process described above, with difference that # we parse asm-prototypes.h C header to get function definitions. cmd_gen_symversions_S = $(call gen_symversions,S) endif $(obj)/%.o: $(src)/%.S FORCE $(call if_changed_rule,as_o_S) targets += $(filter-out $(subdir-builtin), $(real-obj-y)) targets += $(filter-out $(subdir-modorder), $(real-obj-m)) targets += $(real-dtb-y) $(lib-y) $(always-y) # Linker scripts preprocessor (.lds.S -> .lds) # --------------------------------------------------------------------------- quiet_cmd_cpp_lds_S = LDS $@ cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< $(obj)/%.lds: $(src)/%.lds.S FORCE $(call if_changed_dep,cpp_lds_S) # ASN.1 grammar # --------------------------------------------------------------------------- quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ $(basename $@).c $(basename $@).h $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler $(call cmd,asn1_compiler) # Build the compiled-in targets # --------------------------------------------------------------------------- # To build objects in subdirs, we need to descend into the directories $(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; $(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; # # Rule to compile a set of .o files into one .a file (without symbol table) # # To make this rule robust against "Argument list too long" error, # remove $(obj)/ prefix, and restore it by a shell command. quiet_cmd_ar_builtin = AR $@ cmd_ar_builtin = rm -f $@; \ $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \ $(AR) cDPrST $@ $(obj)/built-in.a: $(real-obj-y) FORCE $(call if_changed,ar_builtin) # # Rule to create modules.order file # # Create commands to either record .ko file or cat modules.order from # a subdirectory # Add $(obj-m) as the prerequisite to avoid updating the timestamp of # modules.order unless contained modules are updated. cmd_modules_order = { $(foreach m, $(real-prereqs), \ $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \ > $@ $(obj)/modules.order: $(obj-m) FORCE $(call if_changed,modules_order) # # Rule to compile a set of .o files into one .a file (with symbol table) # $(obj)/lib.a: $(lib-y) FORCE $(call if_changed,ar) quiet_cmd_ld_multi_m = LD [M] $@ cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) $(cmd_objtool) define rule_ld_multi_m $(call cmd_and_savecmd,ld_multi_m) $(call cmd,gen_objtooldep) endef $(multi-obj-m): objtool-enabled := $(delay-objtool) $(multi-obj-m): part-of-module := y $(multi-obj-m): %.o: %.mod FORCE $(call if_changed_rule,ld_multi_m) $(call multi_depend, $(multi-obj-m), .o, -objs -y -m) # Add intermediate targets: # When building objects with specific suffix patterns, add intermediate # targets that the final targets are derived from. intermediate_targets = $(foreach sfx, $(2), \ $(patsubst %$(strip $(1)),%$(sfx), \ $(filter %$(strip $(1)), $(targets)))) # %.asn1.o <- %.asn1.[ch] <- %.asn1 # %.dtb.o <- %.dtb.S <- %.dtb <- %.dts # %.lex.o <- %.lex.c <- %.l # %.tab.o <- %.tab.[ch] <- %.y targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ $(call intermediate_targets, .lex.o, .lex.c) \ $(call intermediate_targets, .tab.o, .tab.c .tab.h) # Build # --------------------------------------------------------------------------- $(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ $(if $(KBUILD_MODULES), $(targets-for-modules)) \ $(subdir-ym) $(always-y) @: # Single targets # --------------------------------------------------------------------------- single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d)) single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS)) $(single-subdir-goals): $(single-subdirs) @: # Descending # --------------------------------------------------------------------------- PHONY += $(subdir-ym) $(subdir-ym): $(Q)$(MAKE) $(build)=$@ \ need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \ $(filter $@/%, $(single-subdir-goals)) # Add FORCE to the prequisites of a target to force it to be always rebuilt. # --------------------------------------------------------------------------- PHONY += FORCE FORCE: targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS)) targets := $(filter-out $(PHONY), $(targets)) # Read all saved command lines and dependencies for the $(targets) we # may be building above, using $(if_changed{,_dep}). As an # optimization, we don't need to read them if the target does not # exist, we will rebuild anyway in that case. existing-targets := $(wildcard $(sort $(targets))) -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) # Create directories for object files if they do not exist obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) # If targets exist, their directories apparently exist. Skip mkdir. existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) ifneq ($(obj-dirs),) $(shell mkdir -p $(obj-dirs)) endif .PHONY: $(PHONY)