# Backward compatibility
  asflags-y  += $(EXTRA_AFLAGS)
  ccflags-y  += $(EXTRA_CFLAGS)
  cppflags-y += $(EXTRA_CPPFLAGS)
  ldflags-y  += $(EXTRA_LDFLAGS)

  #
  # flags that take effect in sub directories
  export KBUILD_SUBDIR_ASFLAGS := $(KBUILD_SUBDIR_ASFLAGS) $(subdir-asflags-y)
  export KBUILD_SUBDIR_CCFLAGS := $(KBUILD_SUBDIR_CCFLAGS) $(subdir-ccflags-y)

  # Figure out what we need to build from the various variables
  # ===========================================================================
  
  # When an object is listed to be built compiled-in and modular,
  # only build the compiled-in version
  
  obj-m := $(filter-out $(obj-y),$(obj-m))
  
  # Libraries are always collected in one lib file.
  # Filter out objects already built-in
  
  lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m)))
  
  
  # Handle objects in subdirs
  # ---------------------------------------------------------------------------
  # o if we encounter foo/ in $(obj-y), replace it by foo/built-in.o
  #   and add the directory to the list of dirs to descend into: $(subdir-y)

  # o if we encounter foo/ in $(obj-m), remove it from $(obj-m)

  #   and add the directory to the list of dirs to descend into: $(subdir-m)

  # Determine modorder.
  # Unfortunately, we don't have information about ordering between -y
  # and -m subdirs.  Just put -y's first.
  modorder	:= $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m:.o=.ko))

  __subdir-y	:= $(patsubst %/,%,$(filter %/, $(obj-y)))
  subdir-y	+= $(__subdir-y)
  __subdir-m	:= $(patsubst %/,%,$(filter %/, $(obj-m)))
  subdir-m	+= $(__subdir-m)
  obj-y		:= $(patsubst %/, %/built-in.o, $(obj-y))
  obj-m		:= $(filter-out %/, $(obj-m))
  
  # Subdirectories we need to descend into
  
  subdir-ym	:= $(sort $(subdir-y) $(subdir-m))

  # if $(foo-objs) exists, foo.o is a composite object

  multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))

  multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m))), $(m))))

  multi-used   := $(multi-used-y) $(multi-used-m)
  single-used-m := $(sort $(filter-out $(multi-used-m),$(obj-m)))
  
  # Build list of the parts of our composite objects, our composite
  # objects depend on those (obviously)
  multi-objs-y := $(foreach m, $(multi-used-y), $($(m:.o=-objs)) $($(m:.o=-y)))
  multi-objs-m := $(foreach m, $(multi-used-m), $($(m:.o=-objs)) $($(m:.o=-y)))
  multi-objs   := $(multi-objs-y) $(multi-objs-m)

  # $(subdir-obj-y) is the list of objects in $(obj-y) which uses dir/ to
  # tell kbuild to descend
  subdir-obj-y := $(filter %/built-in.o, $(obj-y))

  
  # $(obj-dirs) is a list of directories that contain object files

  obj-dirs := $(dir $(multi-objs) $(obj-y))

  
  # Replace multi-part objects by their individual parts, look at local dir only
  real-objs-y := $(foreach m, $(filter-out $(subdir-obj-y), $(obj-y)), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m))) $(extra-y)

  real-objs-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m))),$($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m)),$(m)))

  
  # Add subdir path
  
  extra-y		:= $(addprefix $(obj)/,$(extra-y))
  always		:= $(addprefix $(obj)/,$(always))
  targets		:= $(addprefix $(obj)/,$(targets))

  modorder	:= $(addprefix $(obj)/,$(modorder))

  obj-y		:= $(addprefix $(obj)/,$(obj-y))
  obj-m		:= $(addprefix $(obj)/,$(obj-m))
  lib-y		:= $(addprefix $(obj)/,$(lib-y))
  subdir-obj-y	:= $(addprefix $(obj)/,$(subdir-obj-y))
  real-objs-y	:= $(addprefix $(obj)/,$(real-objs-y))
  real-objs-m	:= $(addprefix $(obj)/,$(real-objs-m))
  single-used-m	:= $(addprefix $(obj)/,$(single-used-m))
  multi-used-y	:= $(addprefix $(obj)/,$(multi-used-y))
  multi-used-m	:= $(addprefix $(obj)/,$(multi-used-m))
  multi-objs-y	:= $(addprefix $(obj)/,$(multi-objs-y))
  multi-objs-m	:= $(addprefix $(obj)/,$(multi-objs-m))
  subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
  obj-dirs	:= $(addprefix $(obj)/,$(obj-dirs))

  # These flags are needed for modversions and compiling, so we define them here
  # already

  # $(modname_flags) #defines KBUILD_MODNAME as the name of the module it will

  # end up in (or would, if it gets compiled in)

  # Note: Files that end up in two or more modules are compiled without the
  #       KBUILD_MODNAME definition. The reason is that any made-up name would
  #       differ in different configs.

  name-fix = $(squote)$(quote)$(subst $(comma),_,$(subst -,_,$1))$(quote)$(squote)
  basename_flags = -DKBUILD_BASENAME=$(call name-fix,$(basetarget))

  modname_flags  = $(if $(filter 1,$(words $(modname))),\

                   -DKBUILD_MODNAME=$(call name-fix,$(modname)))

  orig_c_flags   = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(KBUILD_SUBDIR_CCFLAGS) \

                   $(ccflags-y) $(CFLAGS_$(basetarget).o)

  _c_flags       = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))

  orig_a_flags   = $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(KBUILD_SUBDIR_ASFLAGS) \

                   $(asflags-y) $(AFLAGS_$(basetarget).o)

  _a_flags       = $(filter-out $(AFLAGS_REMOVE_$(basetarget).o), $(orig_a_flags))

  _cpp_flags     = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))

  #
  # Enable gcov profiling flags for a file, directory or for all files depending
  # on variables GCOV_PROFILE_obj.o, GCOV_PROFILE and CONFIG_GCOV_PROFILE_ALL
  # (in this order)
  #
  ifeq ($(CONFIG_GCOV_KERNEL),y)
  _c_flags += $(if $(patsubst n%,, \
  		$(GCOV_PROFILE_$(basetarget).o)$(GCOV_PROFILE)$(CONFIG_GCOV_PROFILE_ALL)), \
  		$(CFLAGS_GCOV))
  endif

  #
  # Enable address sanitizer flags for kernel except some files or directories
  # we don't want to check (depends on variables KASAN_SANITIZE_obj.o, KASAN_SANITIZE)
  #
  ifeq ($(CONFIG_KASAN),y)
  _c_flags += $(if $(patsubst n%,, \
  		$(KASAN_SANITIZE_$(basetarget).o)$(KASAN_SANITIZE)y), \
  		$(CFLAGS_KASAN))
  endif

  ifeq ($(CONFIG_UBSAN),y)
  _c_flags += $(if $(patsubst n%,, \
  		$(UBSAN_SANITIZE_$(basetarget).o)$(UBSAN_SANITIZE)$(CONFIG_UBSAN_SANITIZE_ALL)), \
  		$(CFLAGS_UBSAN))
  endif

  ifeq ($(CONFIG_KCOV),y)
  _c_flags += $(if $(patsubst n%,, \

  	$(KCOV_INSTRUMENT_$(basetarget).o)$(KCOV_INSTRUMENT)$(CONFIG_KCOV_INSTRUMENT_ALL)), \

  	$(CFLAGS_KCOV))
  endif

  # If building the kernel in a separate objtree expand all occurrences
  # of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/').
  
  ifeq ($(KBUILD_SRC),)
  __c_flags	= $(_c_flags)
  __a_flags	= $(_a_flags)
  __cpp_flags     = $(_cpp_flags)
  else

  # -I$(obj) locates generated .h files
  # $(call addtree,-I$(obj)) locates .h files in srctree, from generated .c files
  #   and locates generated .h files
  # FIXME: Replace both with specific CFLAGS* statements in the makefiles

  __c_flags	= $(if $(obj),-I$(srctree)/$(src) -I$(obj)) \
  		  $(call flags,_c_flags)
  __a_flags	= $(call flags,_a_flags)
  __cpp_flags     = $(call flags,_cpp_flags)

  endif

  c_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
  		 $(__c_flags) $(modkern_cflags)                           \

  		 $(basename_flags) $(modname_flags)

  a_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \

  		 $(__a_flags) $(modkern_aflags)

  cpp_flags      = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
  		 $(__cpp_flags)

  ld_flags       = $(LDFLAGS) $(ldflags-y)

  dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \

  		 -I$(srctree)/arch/$(SRCARCH)/boot/dts                   \

  		 -I$(srctree)/arch/$(SRCARCH)/boot/dts/include           \

  		 -I$(srctree)/drivers/of/testcase-data                   \

  		 -undef -D__DTS__

  # Finds the multi-part object the current object will be linked into
  modname-multi = $(sort $(foreach m,$(multi-used),\
  		$(if $(filter $(subst $(obj)/,,$*.o), $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=))))

  # Useful for describing the dependency of composite objects
  # Usage:
  #   $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add)
  define multi_depend
  $(foreach m, $(notdir $1), \
  	$(eval $(obj)/$m: \
  	$(addprefix $(obj)/, $(foreach s, $3, $($(m:%$(strip $2)=%$(s)))))))
  endef

  ifdef REGENERATE_PARSERS
  
  # GPERF
  # ---------------------------------------------------------------------------
  quiet_cmd_gperf = GPERF $@
        cmd_gperf = gperf -t --output-file $@ -a -C -E -g -k 1,3,$$ -p -t $<

  .PRECIOUS: $(src)/%.hash.c_shipped

  $(src)/%.hash.c_shipped: $(src)/%.gperf
  	$(call cmd,gperf)
  
  # LEX
  # ---------------------------------------------------------------------------
  LEX_PREFIX = $(if $(LEX_PREFIX_${baseprereq}),$(LEX_PREFIX_${baseprereq}),yy)
  
  quiet_cmd_flex = LEX     $@
        cmd_flex = flex -o$@ -L -P $(LEX_PREFIX) $<

  .PRECIOUS: $(src)/%.lex.c_shipped

  $(src)/%.lex.c_shipped: $(src)/%.l
  	$(call cmd,flex)
  
  # YACC
  # ---------------------------------------------------------------------------
  YACC_PREFIX = $(if $(YACC_PREFIX_${baseprereq}),$(YACC_PREFIX_${baseprereq}),yy)
  
  quiet_cmd_bison = YACC    $@
        cmd_bison = bison -o$@ -t -l -p $(YACC_PREFIX) $<

  .PRECIOUS: $(src)/%.tab.c_shipped

  $(src)/%.tab.c_shipped: $(src)/%.y
  	$(call cmd,bison)
  
  quiet_cmd_bison_h = YACC    $@
        cmd_bison_h = bison -o/dev/null --defines=$@ -t -l -p $(YACC_PREFIX) $<

  .PRECIOUS: $(src)/%.tab.h_shipped

  $(src)/%.tab.h_shipped: $(src)/%.y
  	$(call cmd,bison_h)
  
  endif

  # Shipped files
  # ===========================================================================
  
  quiet_cmd_shipped = SHIPPED $@
  cmd_shipped = cat $< > $@

  $(obj)/%: $(src)/%_shipped

  	$(call cmd,shipped)
  
  # Commands useful for building a boot image
  # ===========================================================================

  #

  #	Use as following:
  #
  #	target: source(s) FORCE
  #		$(if_changed,ld/objcopy/gzip)
  #

  #	and add target to extra-y so that we know we have to

  #	read in the saved command line
  
  # Linking
  # ---------------------------------------------------------------------------
  
  quiet_cmd_ld = LD      $@

  cmd_ld = $(LD) $(LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F)) \

  	       $(filter-out FORCE,$^) -o $@

  
  # Objcopy
  # ---------------------------------------------------------------------------
  
  quiet_cmd_objcopy = OBJCOPY $@
  cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
  
  # Gzip
  # ---------------------------------------------------------------------------
  
  quiet_cmd_gzip = GZIP    $@

  cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \

  	(rm -f $@ ; false)

  # DTC
  # ---------------------------------------------------------------------------

  DTC ?= $(objtree)/scripts/dtc/dtc

  # Disable noisy checks by default
  ifeq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
  DTC_FLAGS += -Wno-unit_address_vs_reg
  endif

  # Generate an assembly file to wrap the output of the device tree compiler

  quiet_cmd_dt_S_dtb= DTB     $@

  cmd_dt_S_dtb=						\
  (							\
  	echo '\#include <asm-generic/vmlinux.lds.h>'; 	\
  	echo '.section .dtb.init.rodata,"a"';		\
  	echo '.balign STRUCT_ALIGNMENT';		\
  	echo '.global __dtb_$(*F)_begin';		\
  	echo '__dtb_$(*F)_begin:';			\
  	echo '.incbin "$<" ';				\
  	echo '__dtb_$(*F)_end:';			\
  	echo '.global __dtb_$(*F)_end';			\
  	echo '.balign STRUCT_ALIGNMENT'; 		\
  ) > $@
  
  $(obj)/%.dtb.S: $(obj)/%.dtb
  	$(call cmd,dt_S_dtb)
  
  quiet_cmd_dtc = DTC     $@

  cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \
  	$(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \

  	$(DTC) -O dtb -o $@ -b 0 \

  		-i $(dir $<) $(DTC_FLAGS) \

  		-d $(depfile).dtc.tmp $(dtc-tmp) ; \
  	cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)

  $(obj)/%.dtb: $(src)/%.dts FORCE
  	$(call if_changed_dep,dtc)

  dtc-tmp = $(subst $(comma),_,$(dot-target).dts.tmp)

  # Bzip2
  # ---------------------------------------------------------------------------

  # Bzip2 and LZMA do not include size in file... so we have to fake that;
  # append the size as a 32-bit littleendian number as gzip does.

  size_append = printf $(shell						\

  dec_size=0;								\
  for F in $1; do								\
  	fsize=$$(stat -c "%s" $$F);					\
  	dec_size=$$(expr $$dec_size + $$fsize);				\
  done;									\

  printf "%08x
  " $$dec_size |						\
  	sed 's/\(..\)/\1 /g' | {					\
  		read ch0 ch1 ch2 ch3;					\
  		for ch in $$ch3 $$ch2 $$ch1 $$ch0; do			\
  			printf '%s%03o' '\\' $$((0x$$ch)); 		\
  		done;							\
  	}								\

  )
  
  quiet_cmd_bzip2 = BZIP2   $@
  cmd_bzip2 = (cat $(filter-out FORCE,$^) | \
  	bzip2 -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
  	(rm -f $@ ; false)

  
  # Lzma
  # ---------------------------------------------------------------------------
  
  quiet_cmd_lzma = LZMA    $@

  cmd_lzma = (cat $(filter-out FORCE,$^) | \
  	lzma -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
  	(rm -f $@ ; false)

  quiet_cmd_lzo = LZO     $@

  cmd_lzo = (cat $(filter-out FORCE,$^) | \
  	lzop -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
  	(rm -f $@ ; false)

  quiet_cmd_lz4 = LZ4     $@
  cmd_lz4 = (cat $(filter-out FORCE,$^) | \
  	lz4c -l -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
  	(rm -f $@ ; false)

  # U-Boot mkimage
  # ---------------------------------------------------------------------------
  
  MKIMAGE := $(srctree)/scripts/mkuboot.sh
  
  # SRCARCH just happens to match slightly more than ARCH (on sparc), so reduces
  # the number of overrides in arch makefiles
  UIMAGE_ARCH ?= $(SRCARCH)
  UIMAGE_COMPRESSION ?= $(if $(2),$(2),none)
  UIMAGE_OPTS-y ?=
  UIMAGE_TYPE ?= kernel
  UIMAGE_LOADADDR ?= arch_must_set_this
  UIMAGE_ENTRYADDR ?= $(UIMAGE_LOADADDR)
  UIMAGE_NAME ?= 'Linux-$(KERNELRELEASE)'
  UIMAGE_IN ?= $<
  UIMAGE_OUT ?= $@
  
  quiet_cmd_uimage = UIMAGE  $(UIMAGE_OUT)
        cmd_uimage = $(CONFIG_SHELL) $(MKIMAGE) -A $(UIMAGE_ARCH) -O linux \
  			-C $(UIMAGE_COMPRESSION) $(UIMAGE_OPTS-y) \
  			-T $(UIMAGE_TYPE) \
  			-a $(UIMAGE_LOADADDR) -e $(UIMAGE_ENTRYADDR) \
  			-n $(UIMAGE_NAME) -d $(UIMAGE_IN) $(UIMAGE_OUT)

  # XZ
  # ---------------------------------------------------------------------------
  # Use xzkern to compress the kernel image and xzmisc to compress other things.
  #
  # xzkern uses a big LZMA2 dictionary since it doesn't increase memory usage
  # of the kernel decompressor. A BCJ filter is used if it is available for
  # the target architecture. xzkern also appends uncompressed size of the data
  # using size_append. The .xz format has the size information available at
  # the end of the file too, but it's in more complex format and it's good to
  # avoid changing the part of the boot code that reads the uncompressed size.
  # Note that the bytes added by size_append will make the xz tool think that
  # the file is corrupt. This is expected.
  #
  # xzmisc doesn't use size_append, so it can be used to create normal .xz
  # files. xzmisc uses smaller LZMA2 dictionary than xzkern, because a very
  # big dictionary would increase the memory usage too much in the multi-call
  # decompression mode. A BCJ filter isn't used either.
  quiet_cmd_xzkern = XZKERN  $@
  cmd_xzkern = (cat $(filter-out FORCE,$^) | \
  	sh $(srctree)/scripts/xz_wrap.sh && \
  	$(call size_append, $(filter-out FORCE,$^))) > $@ || \
  	(rm -f $@ ; false)
  
  quiet_cmd_xzmisc = XZMISC  $@
  cmd_xzmisc = (cat $(filter-out FORCE,$^) | \
  	xz --check=crc32 --lzma2=dict=1MiB) > $@ || \
  	(rm -f $@ ; false)