# SPDX-License-Identifier: GPL-2.0 # ========================================================================== # Building # ========================================================================== src := $(obj) PHONY := __build __build: # 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 := targets := subdir-y := subdir-m := EXTRA_AFLAGS := EXTRA_CFLAGS := EXTRA_CPPFLAGS := EXTRA_LDFLAGS := asflags-y := ccflags-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 scripts/Kbuild.include # The filename Kbuild has precedence over Makefile kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) include $(kbuild-file) include scripts/Makefile.lib # Do not include host rules unless needed ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),) include scripts/Makefile.host 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.) $(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) endif endif # =========================================================================== ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) lib-target := $(obj)/lib.a real-obj-y += $(obj)/lib-ksyms.o endif ifneq ($(strip $(real-obj-y) $(need-builtin)),) builtin-target := $(obj)/built-in.a endif ifeq ($(CONFIG_MODULES)$(need-modorder),y1) modorder-target := $(obj)/modules.order endif mod-targets := $(patsubst %.o, %.mod, $(obj-m)) # Linus' kernel sanity checking tool ifeq ($(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)) $(DISABLE_LTO) -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) # These mirror gensymtypes_S and co below, keep them in synch. cmd_gensymtypes_c = \ $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ scripts/genksyms/genksyms $(if $(1), -T $(2)) \ $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ $(if $(KBUILD_PRESERVE),-p) \ -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ cmd_cc_symtypes_c = \ $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ test -s $@ || rm -f $@ $(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 -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) quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 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 postprocess them in a way # that they are usable as a linker script # o generate .tmp_.o from .o using the linker to # replace the unresolved symbols __crc_exported_symbol with # the actual value of the checksum generated by genksyms # o remove .tmp_.o to .o ifdef CONFIG_LTO_CLANG # Generate .o.symversions files for each .o with exported symbols, and link these # to the kernel and/or modules at the end. cmd_modversions_c = \ if $(LLVM_NM) $@ | grep -q __ksymtab; then \ $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ > $@.symversions; \ fi; else cmd_modversions_c = \ if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ > $(@D)/.tmp_$(@F:.o=.ver); \ \ $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ -T $(@D)/.tmp_$(@F:.o=.ver); \ mv -f $(@D)/.tmp_$(@F) $@; \ rm -f $(@D)/.tmp_$(@F:.o=.ver); \ fi endif endif ifdef CONFIG_FTRACE_MCOUNT_RECORD ifndef CC_USING_RECORD_MCOUNT # 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 ifdef CONFIG_LTO_CLANG # With LTO, we postpone running recordmcount until after the LTO link step, so # let's export the parameters for the link script. export RECORDMCOUNT_FLAGS else # 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; endif 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 ifndef CONFIG_LTO_CLANG cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ $(sub_cmd_record_mcount)) endif # CONFIG_LTO_CLANG endif # CC_USING_RECORD_MCOUNT endif # CONFIG_FTRACE_MCOUNT_RECORD ifdef CONFIG_STACK_VALIDATION ifneq ($(SKIP_STACK_VALIDATION),1) __objtool_obj := $(objtree)/tools/objtool/objtool objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check) objtool_args += $(if $(part-of-module), --module,) ifndef CONFIG_FRAME_POINTER objtool_args += --no-fp endif ifdef CONFIG_GCOV_KERNEL objtool_args += --no-unreachable endif ifdef CONFIG_RETPOLINE objtool_args += --retpoline endif ifdef CONFIG_X86_SMAP objtool_args += --uaccess endif # '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 cmd_objtool = $(if $(patsubst y%,, \ $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ $(__objtool_obj) $(objtool_args) $@) objtool_obj = $(if $(patsubst y%,, \ $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ $(__objtool_obj)) endif # SKIP_STACK_VALIDATION endif # CONFIG_STACK_VALIDATION # Rebuild all objects when objtool changes, or is enabled/disabled. objtool_dep = $(objtool_obj) \ $(wildcard include/config/orc/unwinder.h \ include/config/stack/validation.h) ifdef CONFIG_TRIM_UNUSED_KSYMS cmd_gen_ksymdeps = \ $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd endif define rule_cc_o_c $(call cmd,checksrc) $(call cmd_and_fixdep,cc_o_c) $(call cmd,gen_ksymdeps) $(call cmd,checkdoc) $(call cmd,objtool) $(call cmd,modversions_c) $(call cmd,record_mcount) endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) $(call cmd,gen_ksymdeps) $(call cmd,objtool) $(call cmd,modversions_S) endef # List module undefined symbols (or empty line if not enabled) ifdef CONFIG_TRIM_UNUSED_KSYMS cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo else cmd_undef_syms = echo endif # Built-in and composite module parts $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE $(call cmd,force_checksrc) $(call if_changed_rule,cc_o_c) cmd_mod = { \ echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ $(cmd_undef_syms); \ } > $@ $(obj)/%.mod: $(obj)/%.o FORCE $(call if_changed,mod) targets += $(mod-targets) 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) # header test (header-test-y, header-test-m target) # --------------------------------------------------------------------------- quiet_cmd_cc_s_h = CC $@ cmd_cc_s_h = $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $< $(obj)/%.h.s: $(src)/%.h FORCE $(call if_changed_dep,cc_s_h) # 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 - | \ scripts/genksyms/genksyms $(if $(1), -T $(2)) \ $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ $(if $(KBUILD_PRESERVE),-p) \ -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ cmd_cc_symtypes_S = \ $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ test -s $@ || rm -f $@ $(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 $@ $< 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_modversions_S = \ if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ > $(@D)/.tmp_$(@F:.o=.ver); \ \ $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ -T $(@D)/.tmp_$(@F:.o=.ver); \ mv -f $(@D)/.tmp_$(@F) $@; \ rm -f $(@D)/.tmp_$(@F:.o=.ver); \ fi endif $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE $(call if_changed_rule,as_o_S) targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y) targets += $(extra-y) $(MAKECMDGOALS) $(always) # 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 $(sort $(subdir-obj-y)): $(subdir-ym) ; # combine symversions for later processing quiet_cmd_update_lto_symversions = SYMVER $@ ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y) cmd_update_lto_symversions = \ rm -f $@.symversions; \ for i in $(filter-out FORCE,$^); do \ if [ -f $$i.symversions ]; then \ cat $$i.symversions \ >> $@.symversions; \ fi; \ done else cmd_update_lto_symversions = echo >/dev/null endif # # Rule to compile a set of .o files into one .a file (without symbol table) # ifdef builtin-target quiet_cmd_ar_builtin = AR $@ cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) quiet_cmd_ar_and_symver = AR $@ cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin) $(builtin-target): $(real-obj-y) FORCE $(call if_changed,ar_and_symver) targets += $(builtin-target) endif # builtin-target # # Rule to create modules.order file # # Create commands to either record .ko file or cat modules.order from # a subdirectory $(modorder-target): $(subdir-ym) FORCE $(Q){ $(foreach m, $(modorder), \ $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \ | $(AWK) '!x[$$0]++' - > $@ # # Rule to compile a set of .o files into one .a file (with symbol table) # ifdef lib-target quiet_cmd_ar_lib = AR $@ cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar) $(lib-target): $(lib-y) FORCE $(call if_changed,ar_lib) targets += $(lib-target) dummy-object = $(obj)/.lib_exports.o ksyms-lds = $(dot-target).lds ifdef CONFIG_LTO_CLANG # Objdump doesn't understand LLVM IR. Use llvm-nm to dump symbols. dump_export_list = $(LLVM_NM) else dump_export_list = $(OBJDUMP) -h endif quiet_cmd_export_list = EXPORTS $@ cmd_export_list = $(dump_export_list) $< | \ sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\ rm -f $(dummy-object);\ echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\ $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\ rm $(dummy-object) $(ksyms-lds) $(obj)/lib-ksyms.o: $(lib-target) FORCE $(call if_changed,export_list) targets += $(obj)/lib-ksyms.o endif # NOTE: # Do not replace $(filter %.o,^) with $(real-prereqs). When a single object # module is turned into a multi object module, $^ will contain header file # dependencies recorded in the .*.cmd file. ifdef CONFIG_LTO_CLANG quiet_cmd_link_multi-m = AR [M] $@ cmd_link_multi-m = \ $(cmd_update_lto_symversions); \ rm -f $@; \ $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(filter %.o,$^) else quiet_cmd_link_multi-m = LD [M] $@ cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) endif $(multi-used-m): FORCE $(call if_changed,link_multi-m) $(call multi_depend, $(multi-used-m), .o, -objs -y -m) targets += $(multi-used-m) targets := $(filter-out $(PHONY), $(targets)) # 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 # --------------------------------------------------------------------------- ifdef single-build curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) # Handle single targets without any rule: show "Nothing to be done for ..." or # "No rule to make target ..." depending on whether the target exists. unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ $(filter $(obj)/%, \ $(filter-out $(curdir-single), \ $(KBUILD_SINGLE_TARGETS)))) __build: $(curdir-single) $(subdir-ym) ifneq ($(unknown-single),) $(Q)$(MAKE) -f /dev/null $(unknown-single) endif @: ifeq ($(curdir-single),) # Nothing to do in this directory. Do not include any .*.cmd file for speed-up targets := else targets += $(curdir-single) endif else __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \ $(subdir-ym) $(always) @: endif # Descending # --------------------------------------------------------------------------- PHONY += $(subdir-ym) $(subdir-ym): $(Q)$(MAKE) $(build)=$@ \ $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \ need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1)) # Add FORCE to the prequisites of a target to force it to be always rebuilt. # --------------------------------------------------------------------------- PHONY += FORCE FORCE: # 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) ifdef building_out_of_srctree # Create directories for object files if they do not exist obj-dirs := $(sort $(obj) $(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 endif .PHONY: $(PHONY)