# 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
$(warning kbuild: Makefile.build is included improperly)
endif
# ===========================================================================
ifneq ($(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
ifdef CONFIG_MODULES
modorder-target := $(obj)/modules.order
endif
# 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) $(always)
@:
# Linus' kernel sanity checking tool
ifeq ($(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_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
$(foreach x, i ll lst o s symtypes, $(patsubst %.o,%.$(x),$(real-obj-m))): \
part-of-module := y
modkern_cflags = \
$(if $(part-of-module), \
$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
quiet_modtag = $(if $(part-of-module),[M], )
quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(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 <file>.o from <file>.c
# o if <file>.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_<file>.o from <file>.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_<file>.o to <file>.o
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
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
# 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)), \
$(sub_cmd_record_mcount))
endif # CC_USING_RECORD_MCOUNT
endif # CONFIG_FTRACE_MCOUNT_RECORD
ifdef CONFIG_STACK_VALIDATION
ifneq ($(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
# '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)
# 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 - | \
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_MODVERSIONS
ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
ifneq ($(ASM_PROTOTYPES),)
# 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
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 $< \
$(subst .h,.c,$@) $(subst .c,.h,$@)
$(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 .a file (without symbol table)
#
ifdef builtin-target
quiet_cmd_ar_builtin = AR $@
cmd_ar_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
$(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 (with symbol table)
#
ifdef lib-target
$(lib-target): $(lib-y) FORCE
$(call if_changed,ar)
targets += $(lib-target)
dummy-object = $(obj)/.lib_exports.o
ksyms-lds = $(dot-target).lds
quiet_cmd_export_list = EXPORTS $@
cmd_export_list = $(OBJDUMP) -h $< | \
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.
quiet_cmd_link_multi-m = LD [M] $@
cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) $(cmd_secanalysis)
$(multi-used-m): FORCE
$(call if_changed,link_multi-m)
@{ echo $(@:.o=.ko); echo $(filter %.o,$^); \
$(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))
# 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)
# 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.
existing-targets := $(wildcard $(sort $(targets)))
-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
ifneq ($(KBUILD_SRC),)
# 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)
