# 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
  
  ifneq ($(KBUILD_SRC),)
  # Create output directory if not already present
  _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
  
  # Create directories for object files if directory does not exist
  # Needed when obj-y := dir/file.o syntax is used
  _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
  endif
  
  ifndef obj
  $(warning kbuild: Makefile.build is included improperly)
  endif
  
  # ===========================================================================
  
  ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
  lib-target := $(obj)/lib.a
  obj-y += $(obj)/lib-ksyms.o
  endif
  
  ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
  builtin-target := $(obj)/built-in.o
  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
  
  # Do section mismatch analysis for each module/built-in.o
  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-objs-m)        : part-of-module := y
  $(real-objs-m:.o=.i)  : part-of-module := y
  $(real-objs-m:.o=.s)  : part-of-module := y
  $(real-objs-m:.o=.lst): part-of-module := y
  
  $(real-objs-m)        : quiet_modtag := [M]
  $(real-objs-m:.o=.i)  : quiet_modtag := [M]
  $(real-objs-m:.o=.s)  : quiet_modtag := [M]
  $(real-objs-m:.o=.lst): quiet_modtag := [M]
  
  $(obj-m)              : quiet_modtag := [M]
  
  # Default for not multi-part modules
  modname = $(basetarget)
  
  $(multi-objs-m)         : modname = $(modname-multi)
  $(multi-objs-m:.o=.i)   : modname = $(modname-multi)
  $(multi-objs-m:.o=.s)   : modname = $(modname-multi)
  $(multi-objs-m:.o=.lst) : modname = $(modname-multi)
  $(multi-objs-y)         : modname = $(modname-multi)
  $(multi-objs-y:.o=.i)   : modname = $(modname-multi)
  $(multi-objs-y:.o=.s)   : modname = $(modname-multi)
  $(multi-objs-y:.o=.lst) : modname = $(modname-multi)
  
  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) $<
  
  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 $(OBJDUMP) -h $(@D)/.tmp_$(@F) >/dev/null 2>/dev/null; then		\
  		if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then	\
  			$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
  			    > $(@D)/$(@F).symversions;				\
  		fi;								\
  	else									\
  		if $(LLVM_DIS) -o=- $(@D)/.tmp_$(@F) | grep -q __ksymtab; then	\
  			$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
  			    > $(@D)/$(@F).symversions;				\
  		fi;								\
  	fi;									\
  	mv -f $(@D)/.tmp_$(@F) $@;
  else
  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
  endif
  
  ifdef CONFIG_FTRACE_MCOUNT_RECORD
  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 # !BUILD_C_RECORDMCOUNT
  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_CPPFLAGS) $(KBUILD_CFLAGS)" \
  	"$(LD)" "$(NM)" "$(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 $(CC_FLAGS_FTRACE),$(_c_flags))" =	\
  	     "$(CC_FLAGS_FTRACE)" ]; then			\
  		$(sub_cmd_record_mcount)			\
  	fi;
  endif
  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
    objtool_args += --retpoline
  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)					  \
  	$(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-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
  $(real-objs-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 += $(real-objs-y) $(real-objs-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
  
  ifdef CONFIG_LTO_CLANG
    ifdef CONFIG_MODVERSIONS
      # combine symversions for later processing
      update_lto_symversions =				\
  	rm -f $@.symversions; 				\
  	for i in $(filter-out FORCE,$^); do		\
  		if [ -f $$i.symversions ]; then		\
  			cat $$i.symversions 		\
  				>> $@.symversions;	\
  		fi;					\
  	done;
    endif
    # rebuild the symbol table with llvm-ar to include IR files
    update_lto_symtable = ;				\
  	mv -f $@ $@.tmp;				\
  	$(LLVM_AR) rcsT$(KBUILD_ARFLAGS) $@ 		\
  		$$($(AR) t $@.tmp); 			\
  	rm -f $@.tmp
  endif
  
  ifdef CONFIG_THIN_ARCHIVES
    cmd_make_builtin = $(update_lto_symversions)	\
  	rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
    cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
    quiet_cmd_link_o_target = AR      $@
  else
    cmd_make_builtin = $(LD) $(ld_flags) -r -o
    cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
    quiet_cmd_link_o_target = LD      $@
  endif
  
  # If the list of objects to link is empty, just create an empty built-in.o
  cmd_link_o_target = $(if $(strip $(obj-y)),\
  		      $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
  		      $(cmd_secanalysis),\
  		      $(cmd_make_empty_builtin) $@)
  
  $(builtin-target): $(obj-y) FORCE
  	$(call if_changed,link_o_target)
  
  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      $@
  
  ifdef CONFIG_THIN_ARCHIVES
    cmd_link_l_target = 					\
  	$(update_lto_symversions)			\
  	rm -f $@; 					\
  	$(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)	\
  	$(update_lto_symtable)
  else
    cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
  endif
  
  $(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
  
  filter_export_list = sed -ne '/___ksymtab/s/.*+\([^ "]*\).*/$(ref_prefix)\1)/p'
  link_export_list = 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)
  
  quiet_cmd_export_list = EXPORTS $@
  
  ifdef CONFIG_LTO_CLANG
  # objdump doesn't understand IR files and llvm-dis doesn't support archives,
  # so we'll walk through each file in the archive separately
  cmd_export_list = 					\
  	rm -f $(ksyms-lds);				\
  	for o in $$($(AR) t $<); do			\
  		if $(OBJDUMP) -h $$o >/dev/null 2>/dev/null; then \
  			$(OBJDUMP) -h $$o | 		\
  				$(filter_export_list) 	\
  				>>$(ksyms-lds);		\
  		else					\
  			$(LLVM_DIS) -o=- $$o |		\
  				$(filter_export_list) 	\
  				>>$(ksyms-lds);		\
  		fi; 					\
  	done;						\
  	$(link_export_list)
  else
  cmd_export_list = $(OBJDUMP) -h $< | $(filter_export_list) >$(ksyms-lds); \
  	$(link_export_list)
  endif
  
  $(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)))), $^)
  
  cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
  
  ifdef CONFIG_THIN_ARCHIVES
    quiet_cmd_link_multi-y = AR      $@
    cmd_link_multi-y = $(update_lto_symversions) \
  	rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps) \
  	$(update_lto_symtable)
  else
    quiet_cmd_link_multi-y = LD      $@
    cmd_link_multi-y = $(cmd_link_multi-link)
  endif
  
  quiet_cmd_link_multi-m = LD [M]  $@
  
  ifdef CONFIG_LTO_CLANG
    # don't compile IR until needed
    cmd_link_multi-m = $(cmd_link_multi-y)
  else
    cmd_link_multi-m = $(cmd_link_multi-link)
  endif
  
  $(multi-used-y): FORCE
  	$(call if_changed,link_multi-y)
  
  $(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-y), .o, -objs -y)
  $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
  
  targets += $(multi-used-y) $(multi-used-m)
  
  
  # Descending
  # ---------------------------------------------------------------------------
  
  PHONY += $(subdir-ym)
  $(subdir-ym):
  	$(Q)$(MAKE) $(build)=$@
  
  # 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.
  
  targets := $(wildcard $(sort $(targets)))
  cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
  
  ifneq ($(cmd_files),)
    include $(cmd_files)
  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)