# 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 # For backward compatibility check that these variables do not change save-cflags := $(CFLAGS) # 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 $(kbuild-file) # If the save-* variables changed error out ifeq ($(KBUILD_NOPEDANTIC),) ifneq ("$(save-cflags)","$(CFLAGS)") $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y) endif endif include scripts/Makefile.lib ifdef host-progs ifneq ($(hostprogs-y),$(host-progs)) $(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!) hostprogs-y += $(host-progs) endif endif # Do not include host rules unless needed ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),) include scripts/Makefile.host endif ifndef obj $(warning kbuild: Makefile.build is included improperly) endif # =========================================================================== ifneq ($(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 modorder-target := $(obj)/modules.order # We keep a list of all modules in $(MODVERDIR) __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \ $(subdir-ym) $(always) @: # Linus' kernel sanity checking tool ifneq ($(KBUILD_CHECKSRC),0) ifeq ($(KBUILD_CHECKSRC),2) quiet_cmd_force_checksrc = CHECK $< cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; else quiet_cmd_checksrc = CHECK $< cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; endif endif ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),) cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< ; endif # Do section mismatch analysis for each module/built-in.a ifdef CONFIG_DEBUG_SECTION_MISMATCH cmd_secanalysis = ; scripts/mod/modpost $@ endif # Compile C sources (.c) # --------------------------------------------------------------------------- # Default is built-in, unless we know otherwise modkern_cflags = \ $(if $(part-of-module), \ $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \ $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL)) quiet_modtag := $(empty) $(empty) $(real-obj-m) : part-of-module := y $(real-obj-m:.o=.i) : part-of-module := y $(real-obj-m:.o=.s) : part-of-module := y $(real-obj-m:.o=.lst): part-of-module := y $(real-obj-m) : quiet_modtag := [M] $(real-obj-m:.o=.i) : quiet_modtag := [M] $(real-obj-m:.o=.s) : quiet_modtag := [M] $(real-obj-m:.o=.lst): quiet_modtag := [M] $(obj-m) : quiet_modtag := [M] quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ cmd_cc_s_c = $(CC) $(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) $< | \ $(GENKSYMS) $(if $(1), -T $(2)) \ $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \ $(patsubst y,-R,$(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 = \ set -e; \ $(call cmd_gensymtypes_c,true,$@) >/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) $@ ifndef CONFIG_MODVERSIONS cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< else # When module versioning is enabled the following steps are executed: # o compile a .tmp_<file>.o from <file>.c # o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does # not export symbols, we just rename .tmp_<file>.o to <file>.o and # are 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 <file>.o from .tmp_<file>.o using the linker to # replace the unresolved symbols __crc_exported_symbol with # the actual value of the checksum generated by genksyms cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $< cmd_modversions_c = \ if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \ $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ > $(@D)/.tmp_$(@F:.o=.ver); \ \ $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \ -T $(@D)/.tmp_$(@F:.o=.ver); \ rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \ else \ mv -f $(@D)/.tmp_$(@F) $@; \ fi; endif ifdef CONFIG_FTRACE_MCOUNT_RECORD ifdef BUILD_C_RECORDMCOUNT ifeq ("$(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 = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ "$(if $(CONFIG_64BIT),64,32)" \ "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \ "$(LD)" "$(NM)" "$(RM)" "$(MV)" \ "$(if $(part-of-module),1,0)" "$(@)"; recordmcount_source := $(srctree)/scripts/recordmcount.pl endif # BUILD_C_RECORDMCOUNT cmd_record_mcount = \ if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" = \ "$(CC_FLAGS_FTRACE)" ]; then \ $(sub_cmd_record_mcount) \ fi; endif # CONFIG_FTRACE_MCOUNT_RECORD ifdef CONFIG_STACK_VALIDATION ifneq ($(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 else objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable) endif ifdef CONFIG_RETPOLINE ifneq ($(RETPOLINE_CFLAGS),) objtool_args += --retpoline endif endif ifdef CONFIG_MODVERSIONS objtool_o = $(@D)/.tmp_$(@F) else objtool_o = $(@) 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_o)";) 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) define rule_cc_o_c $(call echo-cmd,checksrc) $(cmd_checksrc) \ $(call cmd_and_fixdep,cc_o_c) \ $(cmd_checkdoc) \ $(call echo-cmd,objtool) $(cmd_objtool) \ $(cmd_modversions_c) \ $(call echo-cmd,record_mcount) $(cmd_record_mcount) endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) \ $(call echo-cmd,objtool) $(cmd_objtool) \ $(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) # Single-part modules are special since we need to mark them in $(MODVERDIR) $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE $(call cmd,force_checksrc) $(call if_changed_rule,cc_o_c) @{ echo $(@:.o=.ko); echo $@; \ $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod) 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 assembler sources (.S) # --------------------------------------------------------------------------- modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) $(real-obj-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) $(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) # .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 <linux/kernel.h>" ; \ echo "\#include <asm/asm-prototypes.h>" ; \ $(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) $(if $(1), -T $(2)) \ $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \ $(patsubst y,-R,$(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 = \ set -e; \ $(call cmd_gensymtypes_S,true,$@) >/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) $@ ifndef CONFIG_MODVERSIONS cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< else ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h) ifeq ($(ASM_PROTOTYPES),) cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< else # versioning matches the C process described above, with difference that # we parse asm-prototypes.h C header to get function definitions. cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $< cmd_modversions_S = \ if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \ $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ > $(@D)/.tmp_$(@F:.o=.ver); \ \ $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \ -T $(@D)/.tmp_$(@F:.o=.ver); \ rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \ else \ mv -f $(@D)/.tmp_$(@F) $@; \ fi; endif 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 $@ cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ $(subst .h,.c,$@) $(subst .c,.h,$@) .PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.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) ; # # Rule to compile a set of .o files into one .o file # ifdef builtin-target # built-in.a archives are made with no symbol table or index which # makes them small and fast, but unable to be used by the linker. # scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol # table and index. quiet_cmd_ar_builtin = AR $@ cmd_ar_builtin = rm -f $@; \ $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^) $(builtin-target): $(real-obj-y) FORCE $(call if_changed,ar_builtin) 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-cmds = \ $(foreach m, $(modorder), \ $(if $(filter %/modules.order, $m), \ cat $m;, echo kernel/$m;)) $(modorder-target): $(subdir-ym) FORCE $(Q)(cat /dev/null; $(modorder-cmds)) > $@ # # Rule to compile a set of .o files into one .a file # ifdef lib-target quiet_cmd_link_l_target = AR $@ # lib target archives do get a symbol table and index cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y) $(lib-target): $(lib-y) FORCE $(call if_changed,link_l_target) targets += $(lib-target) dummy-object = $(obj)/.lib_exports.o ksyms-lds = $(dot-target).lds ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX ref_prefix = EXTERN(_ else ref_prefix = EXTERN( endif quiet_cmd_export_list = EXPORTS $@ cmd_export_list = $(OBJDUMP) -h $< | \ sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(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 # # Rule to link composite objects # # Composite objects are specified in kbuild makefile as follows: # <composite-object>-objs := <list of .o files> # or # <composite-object>-y := <list of .o files> # or # <composite-object>-m := <list of .o files> # The -m syntax only works if <composite object> is a module link_multi_deps = \ $(filter $(addprefix $(obj)/, \ $($(subst $(obj)/,,$(@:.o=-objs))) \ $($(subst $(obj)/,,$(@:.o=-y))) \ $($(subst $(obj)/,,$(@:.o=-m)))), $^) quiet_cmd_link_multi-m = LD [M] $@ cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) $(multi-used-m): FORCE $(call if_changed,link_multi-m) @{ echo $(@:.o=.ko); echo $(link_multi_deps); \ $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod) $(call multi_depend, $(multi-used-m), .o, -objs -y -m) targets += $(multi-used-m) targets := $(filter-out $(PHONY), $(targets)) # Descending # --------------------------------------------------------------------------- PHONY += $(subdir-ym) $(subdir-ym): $(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),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. cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd)) ifneq ($(cmd_files),) include $(cmd_files) endif ifneq ($(KBUILD_SRC),) # Create directories for object files if they do not exist obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets)))) # If cmd_files exist, their directories apparently exist. Skip mkdir. exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files)))) obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs))) ifneq ($(obj-dirs),) $(shell mkdir -p $(obj-dirs)) endif endif # Declare the contents of the .PHONY variable as phony. We keep that # information in a variable se we can use it in if_changed and friends. .PHONY: $(PHONY)