# 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 :=

  always-y :=
  always-m :=

  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 hostprogs rules unless needed.
  # $(sort ...) is used here to remove duplicated words and excessive spaces.
  hostprogs := $(sort $(hostprogs))

  ifneq ($(hostprogs),)

  include 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 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 := $(patsubst %.o, %.mod, $(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), $(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)

  # 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

  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

  
  # List module undefined symbols
  undefined_syms = $(NM) $< | $(AWK) '$$1 == "U" { printf("%s%s", x++ ? " " : "", $$2) }';

  endif

  define rule_cc_o_c

  	$(call cmd_and_fixdep,cc_o_c)
  	$(call cmd,gen_ksymdeps)

  	$(call cmd,checksrc)

  	$(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

  # Built-in and composite module parts

  $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE

  	$(call if_changed_rule,cc_o_c)

  	$(call cmd,force_checksrc)

  cmd_mod = { \
  	echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \

  	$(undefined_syms) echo; \

  	} > $@
  
  $(obj)/%.mod: $(obj)/%.o FORCE
  	$(call if_changed,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)
  # ---------------------------------------------------------------------------

  # .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_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-builtin), $(real-obj-y))
  targets += $(filter-out $(subdir-modorder), $(real-obj-m))
  targets += $(lib-y) $(always-y) $(MAKECMDGOALS)

  
  # 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)

  #

  quiet_cmd_ar_builtin = AR      $@

        cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs)

  $(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));) :; } \

  	| $(AWK) '!x[$$0]++' - > $@

  $(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)

  # 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 $@ $(filter %.o,$^)

  $(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

  KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS))

  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-out $(curdir-single), $(KBUILD_SINGLE_TARGETS)))

  single-subdirs := $(foreach d, $(subdir-ym), \
  			$(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d)))
  
  __build: $(curdir-single) $(single-subdirs)

  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), $(targets-for-builtin)) \
  	 $(if $(KBUILD_MODULES), $(targets-for-modules)) \

  	 $(subdir-ym) $(always-y)

  	@:
  
  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-builtin)),1) \

  	need-modorder=$(if $(filter $@/modules.order, $(subdir-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)

  # 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)