Makefile - kernel/common - Git at Google

 # SPDX-License-Identifier: GPL-2.0
 VERSION = 5
 PATCHLEVEL = 10
 SUBLEVEL = 105
 EXTRAVERSION =
 NAME = Dare mighty things

 # *DOCUMENTATION*
 # To see a list of typical targets execute "make help"
 # More info can be located in ./README
 # Comments in this file are targeted only to the developer, do not
 # expect to learn how to build the kernel reading this file.

 $(if $(filter __%, $(MAKECMDGOALS)), \
 	$(error targets prefixed with '__' are only for internal use))

 # That's our default target when none is given on the command line
 PHONY := __all
 __all:

 # We are using a recursive build, so we need to do a little thinking
 # to get the ordering right.
 #
 # Most importantly: sub-Makefiles should only ever modify files in
 # their own directory. If in some directory we have a dependency on
 # a file in another dir (which doesn't happen often, but it's often
 # unavoidable when linking the built-in.a targets which finally
 # turn into vmlinux), we will call a sub make in that other dir, and
 # after that we are sure that everything which is in that other dir
 # is now up to date.
 #
 # The only cases where we need to modify files which have global
 # effects are thus separated out and done before the recursive
 # descending is started. They are now explicitly listed as the
 # prepare rule.

 ifneq ($(sub_make_done),1)

 # Do not use make's built-in rules and variables
 # (this increases performance and avoids hard-to-debug behaviour)
 MAKEFLAGS += -rR

 # Avoid funny character set dependencies
 unexport LC_ALL
 LC_COLLATE=C
 LC_NUMERIC=C
 export LC_COLLATE LC_NUMERIC

 # Avoid interference with shell env settings
 unexport GREP_OPTIONS

 # Beautify output
 # ---------------------------------------------------------------------------
 #
 # Normally, we echo the whole command before executing it. By making
 # that echo $($(quiet)$(cmd)), we now have the possibility to set
 # $(quiet) to choose other forms of output instead, e.g.
 #
 #         quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
 #         cmd_cc_o_c       = $(CC) $(c_flags) -c -o $@ $<
 #
 # If $(quiet) is empty, the whole command will be printed.
 # If it is set to "quiet_", only the short version will be printed.
 # If it is set to "silent_", nothing will be printed at all, since
 # the variable $(silent_cmd_cc_o_c) doesn't exist.
 #
 # A simple variant is to prefix commands with $(Q) - that's useful
 # for commands that shall be hidden in non-verbose mode.
 #
 #	$(Q)ln $@ :<
 #
 # If KBUILD_VERBOSE equals 0 then the above command will be hidden.
 # If KBUILD_VERBOSE equals 1 then the above command is displayed.
 # If KBUILD_VERBOSE equals 2 then give the reason why each target is rebuilt.
 #
 # To put more focus on warnings, be less verbose as default
 # Use 'make V=1' to see the full commands

 ifeq ("$(origin V)", "command line")
   KBUILD_VERBOSE = $(V)
 endif
 ifndef KBUILD_VERBOSE
   KBUILD_VERBOSE = 0
 endif

 ifeq ($(KBUILD_VERBOSE),1)
   quiet =
   Q =
 else
   quiet=quiet_
   Q = @
 endif

 # If the user is running make -s (silent mode), suppress echoing of
 # commands

 ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
   quiet=silent_
 endif

 export quiet Q KBUILD_VERBOSE

 # Kbuild will save output files in the current working directory.
 # This does not need to match to the root of the kernel source tree.
 #
 # For example, you can do this:
 #
 #  cd /dir/to/store/output/files; make -f /dir/to/kernel/source/Makefile
 #
 # If you want to save output files in a different location, there are
 # two syntaxes to specify it.
 #
 # 1) O=
 # Use "make O=dir/to/store/output/files/"
 #
 # 2) Set KBUILD_OUTPUT
 # Set the environment variable KBUILD_OUTPUT to point to the output directory.
 # export KBUILD_OUTPUT=dir/to/store/output/files/; make
 #
 # The O= assignment takes precedence over the KBUILD_OUTPUT environment
 # variable.

 # Do we want to change the working directory?
 ifeq ("$(origin O)", "command line")
   KBUILD_OUTPUT := $(O)
 endif

 ifneq ($(KBUILD_OUTPUT),)
 # Make's built-in functions such as $(abspath ...), $(realpath ...) cannot
 # expand a shell special character '~'. We use a somewhat tedious way here.
 abs_objtree := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) && pwd)
 $(if $(abs_objtree),, \
      $(error failed to create output directory "$(KBUILD_OUTPUT)"))

 # $(realpath ...) resolves symlinks
 abs_objtree := $(realpath $(abs_objtree))
 else
 abs_objtree := $(CURDIR)
 endif # ifneq ($(KBUILD_OUTPUT),)

 ifeq ($(abs_objtree),$(CURDIR))
 # Suppress "Entering directory ..." unless we are changing the work directory.
 MAKEFLAGS += --no-print-directory
 else
 need-sub-make := 1
 endif

 abs_srctree := $(realpath $(dir $(lastword $(MAKEFILE_LIST))))

 ifneq ($(words $(subst :, ,$(abs_srctree))), 1)
 $(error source directory cannot contain spaces or colons)
 endif

 ifneq ($(abs_srctree),$(abs_objtree))
 # Look for make include files relative to root of kernel src
 #
 # This does not become effective immediately because MAKEFLAGS is re-parsed
 # once after the Makefile is read. We need to invoke sub-make.
 MAKEFLAGS += --include-dir=$(abs_srctree)
 need-sub-make := 1
 endif

 this-makefile := $(lastword $(MAKEFILE_LIST))

 ifneq ($(filter 3.%,$(MAKE_VERSION)),)
 # 'MAKEFLAGS += -rR' does not immediately become effective for GNU Make 3.x
 # We need to invoke sub-make to avoid implicit rules in the top Makefile.
 need-sub-make := 1
 # Cancel implicit rules for this Makefile.
 $(this-makefile): ;
 endif

 export abs_srctree abs_objtree
 export sub_make_done := 1

 ifeq ($(need-sub-make),1)

 PHONY += $(MAKECMDGOALS) __sub-make

 $(filter-out $(this-makefile), $(MAKECMDGOALS)) __all: __sub-make
 	@:

 # Invoke a second make in the output directory, passing relevant variables
 __sub-make:
 	$(Q)$(MAKE) -C $(abs_objtree) -f $(abs_srctree)/Makefile $(MAKECMDGOALS)

 endif # need-sub-make
 endif # sub_make_done

 # We process the rest of the Makefile if this is the final invocation of make
 ifeq ($(need-sub-make),)

 # Do not print "Entering directory ...",
 # but we want to display it when entering to the output directory
 # so that IDEs/editors are able to understand relative filenames.
 MAKEFLAGS += --no-print-directory

 # Call a source code checker (by default, "sparse") as part of the
 # C compilation.
 #
 # Use 'make C=1' to enable checking of only re-compiled files.
 # Use 'make C=2' to enable checking of *all* source files, regardless
 # of whether they are re-compiled or not.
 #
 # See the file "Documentation/dev-tools/sparse.rst" for more details,
 # including where to get the "sparse" utility.

 ifeq ("$(origin C)", "command line")
   KBUILD_CHECKSRC = $(C)
 endif
 ifndef KBUILD_CHECKSRC
   KBUILD_CHECKSRC = 0
 endif

 # Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the
 # directory of external module to build. Setting M= takes precedence.
 ifeq ("$(origin M)", "command line")
   KBUILD_EXTMOD := $(M)
 endif

 $(if $(word 2, $(KBUILD_EXTMOD)), \
 	$(error building multiple external modules is not supported))

 export KBUILD_CHECKSRC KBUILD_EXTMOD

 extmod-prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)

 ifeq ($(abs_srctree),$(abs_objtree))
         # building in the source tree
         srctree := .
 	building_out_of_srctree :=
 else
         ifeq ($(abs_srctree)/,$(dir $(abs_objtree)))
                 # building in a subdirectory of the source tree
                 srctree := ..
         else
                 srctree := $(abs_srctree)
         endif
 	building_out_of_srctree := 1
 endif

 ifneq ($(KBUILD_ABS_SRCTREE),)
 srctree := $(abs_srctree)
 endif

 objtree		:= .
 VPATH		:= $(srctree)

 export building_out_of_srctree srctree objtree VPATH

 # To make sure we do not include .config for any of the *config targets
 # catch them early, and hand them over to scripts/kconfig/Makefile
 # It is allowed to specify more targets when calling make, including
 # mixing *config targets and build targets.
 # For example 'make oldconfig all'.
 # Detect when mixed targets is specified, and make a second invocation
 # of make so .config is not included in this case either (for *config).

 version_h := include/generated/uapi/linux/version.h
 old_version_h := include/linux/version.h

 clean-targets := %clean mrproper cleandocs
 no-dot-config-targets := $(clean-targets) \
 			 cscope gtags TAGS tags help% %docs check% coccicheck \
 			 $(version_h) headers headers_% archheaders archscripts \
 			 %asm-generic kernelversion %src-pkg dt_binding_check \
 			 outputmakefile
 no-sync-config-targets := $(no-dot-config-targets) %install kernelrelease \
 			  image_name
 single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.s %.symtypes %/

 config-build	:=
 mixed-build	:=
 need-config	:= 1
 may-sync-config	:= 1
 single-build	:=

 ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
 	ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
 		need-config :=
 	endif
 endif

 ifneq ($(filter $(no-sync-config-targets), $(MAKECMDGOALS)),)
 	ifeq ($(filter-out $(no-sync-config-targets), $(MAKECMDGOALS)),)
 		may-sync-config :=
 	endif
 endif

 ifneq ($(KBUILD_EXTMOD),)
 	may-sync-config :=
 endif

 ifeq ($(KBUILD_EXTMOD),)
         ifneq ($(filter %config,$(MAKECMDGOALS)),)
 		config-build := 1
                 ifneq ($(words $(MAKECMDGOALS)),1)
 			mixed-build := 1
                 endif
         endif
 endif

 # We cannot build single targets and the others at the same time
 ifneq ($(filter $(single-targets), $(MAKECMDGOALS)),)
 	single-build := 1
 	ifneq ($(filter-out $(single-targets), $(MAKECMDGOALS)),)
 		mixed-build := 1
 	endif
 endif

 # For "make -j clean all", "make -j mrproper defconfig all", etc.
 ifneq ($(filter $(clean-targets),$(MAKECMDGOALS)),)
         ifneq ($(filter-out $(clean-targets),$(MAKECMDGOALS)),)
 		mixed-build := 1
         endif
 endif

 # install and modules_install need also be processed one by one
 ifneq ($(filter install,$(MAKECMDGOALS)),)
         ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
 		mixed-build := 1
         endif
 endif

 ifdef mixed-build
 # ===========================================================================
 # We're called with mixed targets (*config and build targets).
 # Handle them one by one.

 PHONY += $(MAKECMDGOALS) __build_one_by_one

 $(MAKECMDGOALS): __build_one_by_one
 	@:

 __build_one_by_one:
 	$(Q)set -e; \
 	for i in $(MAKECMDGOALS); do \
 		$(MAKE) -f $(srctree)/Makefile $$i; \
 	done

 else # !mixed-build

 include scripts/Kbuild.include

 # Read KERNELRELEASE from include/config/kernel.release (if it exists)
 KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
 KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION

 include scripts/subarch.include

 # Cross compiling and selecting different set of gcc/bin-utils
 # ---------------------------------------------------------------------------
 #
 # When performing cross compilation for other architectures ARCH shall be set
 # to the target architecture. (See arch/* for the possibilities).
 # ARCH can be set during invocation of make:
 # make ARCH=ia64
 # Another way is to have ARCH set in the environment.
 # The default ARCH is the host where make is executed.

 # CROSS_COMPILE specify the prefix used for all executables used
 # during compilation. Only gcc and related bin-utils executables
 # are prefixed with $(CROSS_COMPILE).
 # CROSS_COMPILE can be set on the command line
 # make CROSS_COMPILE=ia64-linux-
 # Alternatively CROSS_COMPILE can be set in the environment.
 # Default value for CROSS_COMPILE is not to prefix executables
 # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
 ARCH		?= $(SUBARCH)

 # Architecture as present in compile.h
 UTS_MACHINE 	:= $(ARCH)
 SRCARCH 	:= $(ARCH)

 # Additional ARCH settings for x86
 ifeq ($(ARCH),i386)
         SRCARCH := x86
 endif
 ifeq ($(ARCH),x86_64)
         SRCARCH := x86
 endif

 # Additional ARCH settings for sparc
 ifeq ($(ARCH),sparc32)
        SRCARCH := sparc
 endif
 ifeq ($(ARCH),sparc64)
        SRCARCH := sparc
 endif

 # Additional ARCH settings for sh
 ifeq ($(ARCH),sh64)
        SRCARCH := sh
 endif

 KCONFIG_CONFIG	?= .config
 export KCONFIG_CONFIG

 # Default file for 'make defconfig'. This may be overridden by arch-Makefile.
 export KBUILD_DEFCONFIG := defconfig

 # SHELL used by kbuild
 CONFIG_SHELL := sh

 HOST_LFS_CFLAGS := $(shell getconf LFS_CFLAGS 2>/dev/null)
 HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null)
 HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null)

 ifneq ($(LLVM),)
 HOSTCC	= clang
 HOSTCXX	= clang++
 else
 HOSTCC	= gcc
 HOSTCXX	= g++
 endif

 export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
 			      -O2 -fomit-frame-pointer -std=gnu89
 export KBUILD_USERLDFLAGS :=

 KBUILD_HOSTCFLAGS   := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
 KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
 KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
 KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)

 # Make variables (CC, etc...)
 CPP		= $(CC) -E
 ifneq ($(LLVM),)
 CC		= clang
 LD		= ld.lld
 AR		= llvm-ar
 NM		= llvm-nm
 OBJCOPY		= llvm-objcopy
 OBJDUMP		= llvm-objdump
 READELF		= llvm-readelf
 STRIP		= llvm-strip
 else
 CC		= $(CROSS_COMPILE)gcc
 LD		= $(CROSS_COMPILE)ld
 AR		= $(CROSS_COMPILE)ar
 NM		= $(CROSS_COMPILE)nm
 OBJCOPY		= $(CROSS_COMPILE)objcopy
 OBJDUMP		= $(CROSS_COMPILE)objdump
 READELF		= $(CROSS_COMPILE)readelf
 STRIP		= $(CROSS_COMPILE)strip
 endif
 PAHOLE		= pahole
 RESOLVE_BTFIDS	= $(objtree)/tools/bpf/resolve_btfids/resolve_btfids
 LEX		= flex
 YACC		= bison
 AWK		= awk
 INSTALLKERNEL  := installkernel
 DEPMOD		= depmod
 PERL		= perl
 PYTHON		= python
 PYTHON3		= python3
 CHECK		= sparse
 BASH		= bash
 KGZIP		= gzip
 KBZIP2		= bzip2
 KLZOP		= lzop
 LZMA		= lzma
 LZ4		= lz4c
 XZ		= xz
 ZSTD		= zstd

 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
 		  -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF)
 NOSTDINC_FLAGS :=
 CFLAGS_MODULE   =
 AFLAGS_MODULE   =
 LDFLAGS_MODULE  =
 CFLAGS_KERNEL	=
 AFLAGS_KERNEL	=
 LDFLAGS_vmlinux =

 # Use USERINCLUDE when you must reference the UAPI directories only.
 USERINCLUDE    := \
 		-I$(srctree)/arch/$(SRCARCH)/include/uapi \
 		-I$(objtree)/arch/$(SRCARCH)/include/generated/uapi \
 		-I$(srctree)/include/uapi \
 		-I$(objtree)/include/generated/uapi \
                 -include $(srctree)/include/linux/kconfig.h

 # Use LINUXINCLUDE when you must reference the include/ directory.
 # Needed to be compatible with the O= option
 LINUXINCLUDE    := \
 		-I$(srctree)/arch/$(SRCARCH)/include \
 		-I$(objtree)/arch/$(SRCARCH)/include/generated \
 		$(if $(building_out_of_srctree),-I$(srctree)/include) \
 		-I$(objtree)/include \
 		$(USERINCLUDE)

 KBUILD_AFLAGS   := -D__ASSEMBLY__ -fno-PIE
 KBUILD_CFLAGS   := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
 		   -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE \
 		   -Werror=implicit-function-declaration -Werror=implicit-int \
 		   -Werror=return-type -Wno-format-security \
 		   -std=gnu89
 KBUILD_CPPFLAGS := -D__KERNEL__
 KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
 KBUILD_AFLAGS_MODULE  := -DMODULE
 KBUILD_CFLAGS_MODULE  := -DMODULE
 KBUILD_LDFLAGS_MODULE :=
 KBUILD_LDFLAGS :=
 CLANG_FLAGS :=

 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE

 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL

 # Files to ignore in find ... statements

 export RCS_FIND_IGNORE := \( -name SCCS -o -name BitKeeper -o -name .svn -o    \
 			  -name CVS -o -name .pc -o -name .hg -o -name .git \) \
 			  -prune -o
 export RCS_TAR_IGNORE := --exclude SCCS --exclude BitKeeper --exclude .svn \
 			 --exclude CVS --exclude .pc --exclude .hg --exclude .git

 # ===========================================================================
 # Rules shared between *config targets and build targets

 # Basic helpers built in scripts/basic/
 PHONY += scripts_basic
 scripts_basic:
 	$(Q)$(MAKE) $(build)=scripts/basic
 	$(Q)rm -f .tmp_quiet_recordmcount

 PHONY += outputmakefile
 # Before starting out-of-tree build, make sure the source tree is clean.
 # outputmakefile generates a Makefile in the output directory, if using a
 # separate output directory. This allows convenient use of make in the
 # output directory.
 # At the same time when output Makefile generated, generate .gitignore to
 # ignore whole output directory
 outputmakefile:
 ifdef building_out_of_srctree
 	$(Q)if [ -f $(srctree)/.config -o \
 		 -d $(srctree)/include/config -o \
 		 -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \
 		echo >&2 "***"; \
 		echo >&2 "*** The source tree is not clean, please run 'make$(if $(findstring command line, $(origin ARCH)), ARCH=$(ARCH)) mrproper'"; \
 		echo >&2 "*** in $(abs_srctree)";\
 		echo >&2 "***"; \
 		false; \
 	fi
 	$(Q)ln -fsn $(srctree) source
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree)
 	$(Q)test -e .gitignore || \
 	{ echo "# this is build directory, ignore it"; echo "*"; } > .gitignore
 endif

 ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
 ifneq ($(CROSS_COMPILE),)
 CLANG_FLAGS	+= --target=$(notdir $(CROSS_COMPILE:%-=%))
 GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
 CLANG_FLAGS	+= --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
 GCC_TOOLCHAIN	:= $(realpath $(GCC_TOOLCHAIN_DIR)/..)
 endif
 ifneq ($(GCC_TOOLCHAIN),)
 CLANG_FLAGS	+= --gcc-toolchain=$(GCC_TOOLCHAIN)
 endif
 ifneq ($(LLVM_IAS),1)
 CLANG_FLAGS	+= -no-integrated-as
 endif
 CLANG_FLAGS	+= -Werror=unknown-warning-option
 KBUILD_CFLAGS	+= $(CLANG_FLAGS)
 KBUILD_AFLAGS	+= $(CLANG_FLAGS)
 export CLANG_FLAGS
 endif

 # The expansion should be delayed until arch/$(SRCARCH)/Makefile is included.
 # Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
 # CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
 # and from include/config/auto.conf.cmd to detect the compiler upgrade.
 CC_VERSION_TEXT = $(shell $(CC) --version 2>/dev/null | head -n 1)

 ifdef config-build
 # ===========================================================================
 # *config targets only - make sure prerequisites are updated, and descend
 # in scripts/kconfig to make the *config target

 # Read arch specific Makefile to set KBUILD_DEFCONFIG as needed.
 # KBUILD_DEFCONFIG may point out an alternative default configuration
 # used for 'make defconfig'
 include arch/$(SRCARCH)/Makefile
 export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT

 config: outputmakefile scripts_basic FORCE
 	$(Q)$(MAKE) $(build)=scripts/kconfig $@

 %config: outputmakefile scripts_basic FORCE
 	$(Q)$(MAKE) $(build)=scripts/kconfig $@

 else #!config-build
 # ===========================================================================
 # Build targets only - this includes vmlinux, arch specific targets, clean
 # targets and others. In general all targets except *config targets.

 # If building an external module we do not care about the all: rule
 # but instead __all depend on modules
 PHONY += all
 ifeq ($(KBUILD_EXTMOD),)
 __all: all
 else
 __all: modules
 endif

 # Decide whether to build built-in, modular, or both.
 # Normally, just do built-in.

 KBUILD_MODULES :=
 KBUILD_BUILTIN := 1

 # If we have only "make modules", don't compile built-in objects.
 ifeq ($(MAKECMDGOALS),modules)
   KBUILD_BUILTIN :=
 endif

 # If we have "make <whatever> modules", compile modules
 # in addition to whatever we do anyway.
 # Just "make" or "make all" shall build modules as well

 ifneq ($(filter all modules nsdeps %compile_commands.json clang-%,$(MAKECMDGOALS)),)
   KBUILD_MODULES := 1
 endif

 ifeq ($(MAKECMDGOALS),)
   KBUILD_MODULES := 1
 endif

 export KBUILD_MODULES KBUILD_BUILTIN

 ifdef need-config
 include include/config/auto.conf
 endif

 ifeq ($(KBUILD_EXTMOD),)
 # Objects we will link into vmlinux / subdirs we need to visit
 core-y		:= init/ usr/
 drivers-y	:= drivers/ sound/
 drivers-$(CONFIG_SAMPLES) += samples/
 drivers-y	+= net/ virt/
 libs-y		:= lib/
 endif # KBUILD_EXTMOD

 # The all: target is the default when no target is given on the
 # command line.
 # This allow a user to issue only 'make' to build a kernel including modules
 # Defaults to vmlinux, but the arch makefile usually adds further targets
 all: vmlinux

 CFLAGS_GCOV	:= -fprofile-arcs -ftest-coverage \
 	$(call cc-option,-fno-tree-loop-im) \
 	$(call cc-disable-warning,maybe-uninitialized,)
 export CFLAGS_GCOV

 # The arch Makefiles can override CC_FLAGS_FTRACE. We may also append it later.
 ifdef CONFIG_FUNCTION_TRACER
   CC_FLAGS_FTRACE := -pg
 endif

 RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register
 RETPOLINE_VDSO_CFLAGS_GCC := -mindirect-branch=thunk-inline -mindirect-branch-register
 RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
 RETPOLINE_VDSO_CFLAGS_CLANG := -mretpoline
 RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG)))
 RETPOLINE_VDSO_CFLAGS := $(call cc-option,$(RETPOLINE_VDSO_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_VDSO_CFLAGS_CLANG)))
 export RETPOLINE_CFLAGS
 export RETPOLINE_VDSO_CFLAGS

 include arch/$(SRCARCH)/Makefile

 ifdef need-config
 ifdef may-sync-config
 # Read in dependencies to all Kconfig* files, make sure to run syncconfig if
 # changes are detected. This should be included after arch/$(SRCARCH)/Makefile
 # because some architectures define CROSS_COMPILE there.
 include include/config/auto.conf.cmd

 $(KCONFIG_CONFIG):
 	@echo >&2 '***'
 	@echo >&2 '*** Configuration file "$@" not found!'
 	@echo >&2 '***'
 	@echo >&2 '*** Please run some configurator (e.g. "make oldconfig" or'
 	@echo >&2 '*** "make menuconfig" or "make xconfig").'
 	@echo >&2 '***'
 	@/bin/false

 # The actual configuration files used during the build are stored in
 # include/generated/ and include/config/. Update them if .config is newer than
 # include/config/auto.conf (which mirrors .config).
 #
 # This exploits the 'multi-target pattern rule' trick.
 # The syncconfig should be executed only once to make all the targets.
 # (Note: use the grouped target '&:' when we bump to GNU Make 4.3)
 #
 # Do not use $(call cmd,...) here. That would suppress prompts from syncconfig,
 # so you cannot notice that Kconfig is waiting for the user input.
 %/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h: $(KCONFIG_CONFIG)
 	$(Q)$(kecho) "  SYNC    $@"
 	$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig
 else # !may-sync-config
 # External modules and some install targets need include/generated/autoconf.h
 # and include/config/auto.conf but do not care if they are up-to-date.
 # Use auto.conf to trigger the test
 PHONY += include/config/auto.conf

 include/config/auto.conf:
 	$(Q)test -e include/generated/autoconf.h -a -e $@ || (		\
 	echo >&2;							\
 	echo >&2 "  ERROR: Kernel configuration is invalid.";		\
 	echo >&2 "         include/generated/autoconf.h or $@ are missing.";\
 	echo >&2 "         Run 'make oldconfig && make prepare' on kernel src to fix it.";	\
 	echo >&2 ;							\
 	/bin/false)

 endif # may-sync-config
 endif # need-config

 KBUILD_CFLAGS	+= $(call cc-option,-fno-delete-null-pointer-checks,)
 KBUILD_CFLAGS	+= $(call cc-disable-warning,frame-address,)
 KBUILD_CFLAGS	+= $(call cc-disable-warning, format-truncation)
 KBUILD_CFLAGS	+= $(call cc-disable-warning, format-overflow)
 KBUILD_CFLAGS	+= $(call cc-disable-warning, address-of-packed-member)

 ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
 KBUILD_CFLAGS += -O2
 else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3
 KBUILD_CFLAGS += -O3
 else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 KBUILD_CFLAGS += -Os
 endif

 # Tell gcc to never replace conditional load with a non-conditional one
 KBUILD_CFLAGS	+= $(call cc-option,--param=allow-store-data-races=0)
 KBUILD_CFLAGS	+= $(call cc-option,-fno-allow-store-data-races)

 ifdef CONFIG_READABLE_ASM
 # Disable optimizations that make assembler listings hard to read.
 # reorder blocks reorders the control in the function
 # ipa clone creates specialized cloned functions
 # partial inlining inlines only parts of functions
 KBUILD_CFLAGS += $(call cc-option,-fno-reorder-blocks,) \
                  $(call cc-option,-fno-ipa-cp-clone,) \
                  $(call cc-option,-fno-partial-inlining)
 endif

 ifneq ($(CONFIG_FRAME_WARN),0)
 KBUILD_CFLAGS += -Wframe-larger-than=$(CONFIG_FRAME_WARN)
 endif

 stackp-flags-y                                    := -fno-stack-protector
 stackp-flags-$(CONFIG_STACKPROTECTOR)             := -fstack-protector
 stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG)      := -fstack-protector-strong

 KBUILD_CFLAGS += $(stackp-flags-y)

 ifdef CONFIG_CC_IS_CLANG
 KBUILD_CPPFLAGS += -Qunused-arguments
 KBUILD_CFLAGS += -Wno-format-invalid-specifier
 KBUILD_CFLAGS += -Wno-gnu
 # CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
 # source of a reference will be _MergedGlobals and not on of the whitelisted names.
 # See modpost pattern 2
 KBUILD_CFLAGS += -mno-global-merge
 else

 # Warn about unmarked fall-throughs in switch statement.
 # Disabled for clang while comment to attribute conversion happens and
 # https://github.com/ClangBuiltLinux/linux/issues/636 is discussed.
 KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough,)
 endif

 # These warnings generated too much noise in a regular build.
 # Use make W=1 to enable them (see scripts/Makefile.extrawarn)
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)

 KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
 ifdef CONFIG_FRAME_POINTER
 KBUILD_CFLAGS	+= -fno-omit-frame-pointer -fno-optimize-sibling-calls
 else
 # Some targets (ARM with Thumb2, for example), can't be built with frame
 # pointers.  For those, we don't have FUNCTION_TRACER automatically
 # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
 # incompatible with -fomit-frame-pointer with current GCC, so we don't use
 # -fomit-frame-pointer with FUNCTION_TRACER.
 ifndef CONFIG_FUNCTION_TRACER
 KBUILD_CFLAGS	+= -fomit-frame-pointer
 endif
 endif

 # Initialize all stack variables with a 0xAA pattern.
 ifdef CONFIG_INIT_STACK_ALL_PATTERN
 KBUILD_CFLAGS	+= -ftrivial-auto-var-init=pattern
 endif

 # Initialize all stack variables with a zero value.
 ifdef CONFIG_INIT_STACK_ALL_ZERO
 # Future support for zero initialization is still being debated, see
 # https://bugs.llvm.org/show_bug.cgi?id=45497. These flags are subject to being
 # renamed or dropped.
 KBUILD_CFLAGS	+= -ftrivial-auto-var-init=zero
 KBUILD_CFLAGS	+= -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
 endif

 DEBUG_CFLAGS	:=

 # Workaround for GCC versions < 5.0
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61801
 ifdef CONFIG_CC_IS_GCC
 DEBUG_CFLAGS	+= $(call cc-ifversion, -lt, 0500, $(call cc-option, -fno-var-tracking-assignments))
 endif

 ifdef CONFIG_DEBUG_INFO

 ifdef CONFIG_DEBUG_INFO_SPLIT
 DEBUG_CFLAGS	+= -gsplit-dwarf
 else
 DEBUG_CFLAGS	+= -g
 endif

 ifneq ($(LLVM_IAS),1)
 KBUILD_AFLAGS	+= -Wa,-gdwarf-2
 endif

 ifdef CONFIG_DEBUG_INFO_DWARF4
 DEBUG_CFLAGS	+= -gdwarf-4
 endif

 ifdef CONFIG_DEBUG_INFO_REDUCED
 DEBUG_CFLAGS	+= $(call cc-option, -femit-struct-debug-baseonly) \
 		   $(call cc-option,-fno-var-tracking)
 endif

 ifdef CONFIG_DEBUG_INFO_COMPRESSED
 DEBUG_CFLAGS	+= -gz=zlib
 KBUILD_AFLAGS	+= -gz=zlib
 KBUILD_LDFLAGS	+= --compress-debug-sections=zlib
 endif

 endif # CONFIG_DEBUG_INFO

 KBUILD_CFLAGS += $(DEBUG_CFLAGS)
 export DEBUG_CFLAGS

 ifdef CONFIG_FUNCTION_TRACER
 ifdef CONFIG_FTRACE_MCOUNT_RECORD
   # gcc 5 supports generating the mcount tables directly
   ifeq ($(call cc-option-yn,-mrecord-mcount),y)
     CC_FLAGS_FTRACE	+= -mrecord-mcount
     export CC_USING_RECORD_MCOUNT := 1
   endif
   ifdef CONFIG_HAVE_NOP_MCOUNT
     ifeq ($(call cc-option-yn, -mnop-mcount),y)
       CC_FLAGS_FTRACE	+= -mnop-mcount
       CC_FLAGS_USING	+= -DCC_USING_NOP_MCOUNT
     endif
   endif
 endif
 ifdef CONFIG_HAVE_FENTRY
   ifeq ($(call cc-option-yn, -mfentry),y)
     CC_FLAGS_FTRACE	+= -mfentry
     CC_FLAGS_USING	+= -DCC_USING_FENTRY
   endif
 endif
 export CC_FLAGS_FTRACE
 KBUILD_CFLAGS	+= $(CC_FLAGS_FTRACE) $(CC_FLAGS_USING)
 KBUILD_AFLAGS	+= $(CC_FLAGS_USING)
 ifdef CONFIG_DYNAMIC_FTRACE
 	ifdef CONFIG_HAVE_C_RECORDMCOUNT
 		BUILD_C_RECORDMCOUNT := y
 		export BUILD_C_RECORDMCOUNT
 	endif
 endif
 endif

 # We trigger additional mismatches with less inlining
 ifdef CONFIG_DEBUG_SECTION_MISMATCH
 KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once)
 endif

 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
 KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections
 LDFLAGS_vmlinux += --gc-sections
 endif

 ifdef CONFIG_SHADOW_CALL_STACK
 CC_FLAGS_SCS	:= -fsanitize=shadow-call-stack
 KBUILD_CFLAGS	+= $(CC_FLAGS_SCS)
 export CC_FLAGS_SCS
 endif

 ifdef CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_32B
 KBUILD_CFLAGS += -falign-functions=32
 endif

 # arch Makefile may override CC so keep this after arch Makefile is included
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)

 # warn about C99 declaration after statement
 KBUILD_CFLAGS += -Wdeclaration-after-statement

 # Variable Length Arrays (VLAs) should not be used anywhere in the kernel
 KBUILD_CFLAGS += -Wvla

 # disable pointer signed / unsigned warnings in gcc 4.0
 KBUILD_CFLAGS += -Wno-pointer-sign

 # disable stringop warnings in gcc 8+
 KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)

 # We'll want to enable this eventually, but it's not going away for 5.7 at least
 KBUILD_CFLAGS += $(call cc-disable-warning, zero-length-bounds)
 KBUILD_CFLAGS += $(call cc-disable-warning, array-bounds)
 KBUILD_CFLAGS += $(call cc-disable-warning, stringop-overflow)

 # Another good warning that we'll want to enable eventually
 KBUILD_CFLAGS += $(call cc-disable-warning, restrict)

 # Enabled with W=2, disabled by default as noisy
 KBUILD_CFLAGS += $(call cc-disable-warning, maybe-uninitialized)

 # disable invalid "can't wrap" optimizations for signed / pointers
 KBUILD_CFLAGS	+= -fno-strict-overflow

 # Make sure -fstack-check isn't enabled (like gentoo apparently did)
 KBUILD_CFLAGS  += -fno-stack-check

 # conserve stack if available
 KBUILD_CFLAGS   += $(call cc-option,-fconserve-stack)

 # Prohibit date/time macros, which would make the build non-deterministic
 KBUILD_CFLAGS   += -Werror=date-time

 # enforce correct pointer usage
 KBUILD_CFLAGS   += $(call cc-option,-Werror=incompatible-pointer-types)

 # Require designated initializers for all marked structures
 KBUILD_CFLAGS   += $(call cc-option,-Werror=designated-init)

 # change __FILE__ to the relative path from the srctree
 KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)

 # include additional Makefiles when needed
 include-y			:= scripts/Makefile.extrawarn
 include-$(CONFIG_KASAN)		+= scripts/Makefile.kasan
 include-$(CONFIG_KCSAN)		+= scripts/Makefile.kcsan
 include-$(CONFIG_UBSAN)		+= scripts/Makefile.ubsan
 include-$(CONFIG_KCOV)		+= scripts/Makefile.kcov
 include-$(CONFIG_GCC_PLUGINS)	+= scripts/Makefile.gcc-plugins

 include $(addprefix $(srctree)/, $(include-y))

 # scripts/Makefile.gcc-plugins is intentionally included last.
 # Do not add $(call cc-option,...) below this line. When you build the kernel
 # from the clean source tree, the GCC plugins do not exist at this point.

 # Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
 KBUILD_CPPFLAGS += $(KCPPFLAGS)
 KBUILD_AFLAGS   += $(KAFLAGS)
 KBUILD_CFLAGS   += $(KCFLAGS)

 KBUILD_LDFLAGS_MODULE += --build-id=sha1
 LDFLAGS_vmlinux += --build-id=sha1

 ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
 LDFLAGS_vmlinux	+= $(call ld-option, -X,)
 endif

 ifeq ($(CONFIG_RELR),y)
 LDFLAGS_vmlinux	+= --pack-dyn-relocs=relr --use-android-relr-tags
 endif

 # We never want expected sections to be placed heuristically by the
 # linker. All sections should be explicitly named in the linker script.
 ifdef CONFIG_LD_ORPHAN_WARN
 LDFLAGS_vmlinux += --orphan-handling=warn
 endif

 # Align the bit size of userspace programs with the kernel
 KBUILD_USERCFLAGS  += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
 KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))

 # make the checker run with the right architecture
 CHECKFLAGS += --arch=$(ARCH)

 # insure the checker run with the right endianness
 CHECKFLAGS += $(if $(CONFIG_CPU_BIG_ENDIAN),-mbig-endian,-mlittle-endian)

 # the checker needs the correct machine size
 CHECKFLAGS += $(if $(CONFIG_64BIT),-m64,-m32)

 # Default kernel image to build when no specific target is given.
 # KBUILD_IMAGE may be overruled on the command line or
 # set in the environment
 # Also any assignments in arch/$(ARCH)/Makefile take precedence over
 # this default value
 export KBUILD_IMAGE ?= vmlinux

 #
 # INSTALL_PATH specifies where to place the updated kernel and system map
 # images. Default is /boot, but you can set it to other values
 export	INSTALL_PATH ?= /boot

 #
 # INSTALL_DTBS_PATH specifies a prefix for relocations required by build roots.
 # Like INSTALL_MOD_PATH, it isn't defined in the Makefile, but can be passed as
 # an argument if needed. Otherwise it defaults to the kernel install path
 #
 export INSTALL_DTBS_PATH ?= $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)

 #
 # INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
 # relocations required by build roots.  This is not defined in the
 # makefile but the argument can be passed to make if needed.
 #

 MODLIB	= $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
 export MODLIB

 #
 # INSTALL_MOD_STRIP, if defined, will cause modules to be
 # stripped after they are installed.  If INSTALL_MOD_STRIP is '1', then
 # the default option --strip-debug will be used.  Otherwise,
 # INSTALL_MOD_STRIP value will be used as the options to the strip command.

 ifdef INSTALL_MOD_STRIP
 ifeq ($(INSTALL_MOD_STRIP),1)
 mod_strip_cmd = $(STRIP) --strip-debug
 else
 mod_strip_cmd = $(STRIP) $(INSTALL_MOD_STRIP)
 endif # INSTALL_MOD_STRIP=1
 else
 mod_strip_cmd = true
 endif # INSTALL_MOD_STRIP
 export mod_strip_cmd

 # CONFIG_MODULE_COMPRESS, if defined, will cause module to be compressed
 # after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP
 # or CONFIG_MODULE_COMPRESS_XZ.

 mod_compress_cmd = true
 ifdef CONFIG_MODULE_COMPRESS
   ifdef CONFIG_MODULE_COMPRESS_GZIP
     mod_compress_cmd = $(KGZIP) -n -f
   endif # CONFIG_MODULE_COMPRESS_GZIP
   ifdef CONFIG_MODULE_COMPRESS_XZ
     mod_compress_cmd = $(XZ) -f
   endif # CONFIG_MODULE_COMPRESS_XZ
 endif # CONFIG_MODULE_COMPRESS
 export mod_compress_cmd

 ifdef CONFIG_MODULE_SIG_ALL
 $(eval $(call config_filename,MODULE_SIG_KEY))

 mod_sign_cmd = scripts/sign-file $(CONFIG_MODULE_SIG_HASH) $(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY) certs/signing_key.x509
 else
 mod_sign_cmd = true
 endif
 export mod_sign_cmd

 HOST_LIBELF_LIBS = $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)

 has_libelf = $(call try-run,\
                echo "int main() {}" | $(HOSTCC) $(KBUILD_HOSTLDFLAGS) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)

 ifdef CONFIG_STACK_VALIDATION
   ifeq ($(has_libelf),1)
     objtool_target := tools/objtool FORCE
   else
     SKIP_STACK_VALIDATION := 1
     export SKIP_STACK_VALIDATION
   endif
 endif

 PHONY += resolve_btfids_clean

 resolve_btfids_O = $(abspath $(objtree))/tools/bpf/resolve_btfids

 # tools/bpf/resolve_btfids directory might not exist
 # in output directory, skip its clean in that case
 resolve_btfids_clean:
 ifneq ($(wildcard $(resolve_btfids_O)),)
 	$(Q)$(MAKE) -sC $(srctree)/tools/bpf/resolve_btfids O=$(resolve_btfids_O) clean
 endif

 ifdef CONFIG_BPF
 ifdef CONFIG_DEBUG_INFO_BTF
   ifeq ($(has_libelf),1)
     resolve_btfids_target := tools/bpf/resolve_btfids FORCE
   else
     ERROR_RESOLVE_BTFIDS := 1
   endif
 endif # CONFIG_DEBUG_INFO_BTF
 endif # CONFIG_BPF

 PHONY += prepare0

 export MODORDER := $(extmod-prefix)modules.order
 export MODULES_NSDEPS := $(extmod-prefix)modules.nsdeps

 ifeq ($(KBUILD_EXTMOD),)
 core-y		+= kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/

 vmlinux-dirs	:= $(patsubst %/,%,$(filter %/, \
 		     $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
 		     $(libs-y) $(libs-m)))

 vmlinux-alldirs	:= $(sort $(vmlinux-dirs) Documentation \
 		     $(patsubst %/,%,$(filter %/, $(core-) \
 			$(drivers-) $(libs-))))

 subdir-modorder := $(addsuffix modules.order,$(filter %/, \
 			$(core-y) $(core-m) $(libs-y) $(libs-m) \
 			$(drivers-y) $(drivers-m)))

 build-dirs	:= $(vmlinux-dirs)
 clean-dirs	:= $(vmlinux-alldirs)

 # Externally visible symbols (used by link-vmlinux.sh)
 KBUILD_VMLINUX_OBJS := $(head-y) $(patsubst %/,%/built-in.a, $(core-y))
 KBUILD_VMLINUX_OBJS += $(addsuffix built-in.a, $(filter %/, $(libs-y)))
 ifdef CONFIG_MODULES
 KBUILD_VMLINUX_OBJS += $(patsubst %/, %/lib.a, $(filter %/, $(libs-y)))
 KBUILD_VMLINUX_LIBS := $(filter-out %/, $(libs-y))
 else
 KBUILD_VMLINUX_LIBS := $(patsubst %/,%/lib.a, $(libs-y))
 endif
 KBUILD_VMLINUX_OBJS += $(patsubst %/,%/built-in.a, $(drivers-y))

 export KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LIBS
 export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
 # used by scripts/Makefile.package
 export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) LICENSES arch include scripts tools)

 vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)

 # Recurse until adjust_autoksyms.sh is satisfied
 PHONY += autoksyms_recursive
 ifdef CONFIG_TRIM_UNUSED_KSYMS
 # For the kernel to actually contain only the needed exported symbols,
 # we have to build modules as well to determine what those symbols are.
 # (this can be evaluated only once include/config/auto.conf has been included)
 KBUILD_MODULES := 1

 autoksyms_recursive: descend modules.order
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
 	  "$(MAKE) -f $(srctree)/Makefile vmlinux"
 endif

 autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h)

 quiet_cmd_autoksyms_h = GEN     $@
       cmd_autoksyms_h = mkdir -p $(dir $@); \
 			$(CONFIG_SHELL) $(srctree)/scripts/gen_autoksyms.sh $@

 $(autoksyms_h):
 	$(call cmd,autoksyms_h)

 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)

 # Final link of vmlinux with optional arch pass after final link
 cmd_link-vmlinux =                                                 \
 	$(CONFIG_SHELL) $< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)";    \
 	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)

 vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps) FORCE
 	+$(call if_changed,link-vmlinux)

 targets := vmlinux

 # The actual objects are generated when descending,
 # make sure no implicit rule kicks in
 $(sort $(vmlinux-deps) $(subdir-modorder)): descend ;

 filechk_kernel.release = \
 	echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"

 # Store (new) KERNELRELEASE string in include/config/kernel.release
 include/config/kernel.release: FORCE
 	$(call filechk,kernel.release)

 # Additional helpers built in scripts/
 # Carefully list dependencies so we do not try to build scripts twice
 # in parallel
 PHONY += scripts
 scripts: scripts_basic scripts_dtc
 	$(Q)$(MAKE) $(build)=$(@)

 # Things we need to do before we recursively start building the kernel
 # or the modules are listed in "prepare".
 # A multi level approach is used. prepareN is processed before prepareN-1.
 # archprepare is used in arch Makefiles and when processed asm symlink,
 # version.h and scripts_basic is processed / created.

 PHONY += prepare archprepare

 archprepare: outputmakefile archheaders archscripts scripts include/config/kernel.release \
 	asm-generic $(version_h) $(autoksyms_h) include/generated/utsrelease.h \
 	include/generated/autoconf.h

 prepare0: archprepare
 	$(Q)$(MAKE) $(build)=scripts/mod
 	$(Q)$(MAKE) $(build)=.

 # All the preparing..
 prepare: prepare0 prepare-objtool prepare-resolve_btfids

 # Support for using generic headers in asm-generic
 asm-generic := -f $(srctree)/scripts/Makefile.asm-generic obj

 PHONY += asm-generic uapi-asm-generic
 asm-generic: uapi-asm-generic
 	$(Q)$(MAKE) $(asm-generic)=arch/$(SRCARCH)/include/generated/asm \
 	generic=include/asm-generic
 uapi-asm-generic:
 	$(Q)$(MAKE) $(asm-generic)=arch/$(SRCARCH)/include/generated/uapi/asm \
 	generic=include/uapi/asm-generic

 PHONY += prepare-objtool prepare-resolve_btfids
 prepare-objtool: $(objtool_target)
 ifeq ($(SKIP_STACK_VALIDATION),1)
 ifdef CONFIG_UNWINDER_ORC
 	@echo "error: Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
 	@false
 else
 	@echo "warning: Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
 endif
 endif

 prepare-resolve_btfids: $(resolve_btfids_target)
 ifeq ($(ERROR_RESOLVE_BTFIDS),1)
 	@echo "error: Cannot resolve BTF IDs for CONFIG_DEBUG_INFO_BTF, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
 	@false
 endif
 # Generate some files
 # ---------------------------------------------------------------------------

 # KERNELRELEASE can change from a few different places, meaning version.h
 # needs to be updated, so this check is forced on all builds

 uts_len := 64
 define filechk_utsrelease.h
 	if [ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt $(uts_len) ]; then \
 	  echo '"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2;    \
 	  exit 1;                                                         \
 	fi;                                                               \
 	echo \#define UTS_RELEASE \"$(KERNELRELEASE)\"
 endef

 define filechk_version.h
 	if [ $(SUBLEVEL) -gt 255 ]; then                                 \
 		echo \#define LINUX_VERSION_CODE $(shell                 \
 		expr $(VERSION) \* 65536 + $(PATCHLEVEL) \* 256 + 255); \
 	else                                                             \
 		echo \#define LINUX_VERSION_CODE $(shell                 \
 		expr $(VERSION) \* 65536 + $(PATCHLEVEL) \* 256 + $(SUBLEVEL)); \
 	fi;                                                              \
 	echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) +  \
 	((c) > 255 ? 255 : (c)))'
 endef

 $(version_h): PATCHLEVEL := $(if $(PATCHLEVEL), $(PATCHLEVEL), 0)
 $(version_h): SUBLEVEL := $(if $(SUBLEVEL), $(SUBLEVEL), 0)
 $(version_h): FORCE
 	$(call filechk,version.h)
 	$(Q)rm -f $(old_version_h)

 include/generated/utsrelease.h: include/config/kernel.release FORCE
 	$(call filechk,utsrelease.h)

 PHONY += headerdep
 headerdep:
 	$(Q)find $(srctree)/include/ -name '*.h' | xargs --max-args 1 \
 	$(srctree)/scripts/headerdep.pl -I$(srctree)/include

 # ---------------------------------------------------------------------------
 # Kernel headers

 #Default location for installed headers
 export INSTALL_HDR_PATH = $(objtree)/usr

 quiet_cmd_headers_install = INSTALL $(INSTALL_HDR_PATH)/include
       cmd_headers_install = \
 	mkdir -p $(INSTALL_HDR_PATH); \
 	rsync -mrl --include='*/' --include='*\.h' --exclude='*' \
 	usr/include $(INSTALL_HDR_PATH)

 PHONY += headers_install
 headers_install: headers
 	$(call cmd,headers_install)

 PHONY += archheaders archscripts

 hdr-inst := -f $(srctree)/scripts/Makefile.headersinst obj

 PHONY += headers
 headers: $(version_h) scripts_unifdef uapi-asm-generic archheaders archscripts
 	$(if $(wildcard $(srctree)/arch/$(SRCARCH)/include/uapi/asm/Kbuild),, \
 	  $(error Headers not exportable for the $(SRCARCH) architecture))
 	$(Q)$(MAKE) $(hdr-inst)=include/uapi
 	$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi

 # Deprecated. It is no-op now.
 PHONY += headers_check
 headers_check:
 	@:

 ifdef CONFIG_HEADERS_INSTALL
 prepare: headers
 endif

 PHONY += scripts_unifdef
 scripts_unifdef: scripts_basic
 	$(Q)$(MAKE) $(build)=scripts scripts/unifdef

 # ---------------------------------------------------------------------------
 # Kernel selftest

 PHONY += kselftest
 kselftest:
 	$(Q)$(MAKE) -C $(srctree)/tools/testing/selftests run_tests

 kselftest-%: FORCE
 	$(Q)$(MAKE) -C $(srctree)/tools/testing/selftests $*

 PHONY += kselftest-merge
 kselftest-merge:
 	$(if $(wildcard $(objtree)/.config),, $(error No .config exists, config your kernel first!))
 	$(Q)find $(srctree)/tools/testing/selftests -name config | \
 		xargs $(srctree)/scripts/kconfig/merge_config.sh -m $(objtree)/.config
 	$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig

 # ---------------------------------------------------------------------------
 # Devicetree files

 ifneq ($(wildcard $(srctree)/arch/$(SRCARCH)/boot/dts/),)
 dtstree := arch/$(SRCARCH)/boot/dts
 endif

 ifneq ($(dtstree),)

 %.dtb: include/config/kernel.release scripts_dtc
 	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@

 PHONY += dtbs dtbs_install dtbs_check
 dtbs: include/config/kernel.release scripts_dtc
 	$(Q)$(MAKE) $(build)=$(dtstree)

 ifneq ($(filter dtbs_check, $(MAKECMDGOALS)),)
 export CHECK_DTBS=y
 dtbs: dt_binding_check
 endif

 dtbs_check: dtbs

 dtbs_install:
 	$(Q)$(MAKE) $(dtbinst)=$(dtstree) dst=$(INSTALL_DTBS_PATH)

 ifdef CONFIG_OF_EARLY_FLATTREE
 all: dtbs
 endif

 endif

 PHONY += scripts_dtc
 scripts_dtc: scripts_basic
 	$(Q)$(MAKE) $(build)=scripts/dtc

 ifneq ($(filter dt_binding_check, $(MAKECMDGOALS)),)
 export CHECK_DT_BINDING=y
 endif

 PHONY += dt_binding_check
 dt_binding_check: scripts_dtc
 	$(Q)$(MAKE) $(build)=Documentation/devicetree/bindings

 # ---------------------------------------------------------------------------
 # Modules

 ifdef CONFIG_MODULES

 # By default, build modules as well

 all: modules

 # When we're building modules with modversions, we need to consider
 # the built-in objects during the descend as well, in order to
 # make sure the checksums are up to date before we record them.
 ifdef CONFIG_MODVERSIONS
   KBUILD_BUILTIN := 1
 endif

 # Build modules
 #
 # A module can be listed more than once in obj-m resulting in
 # duplicate lines in modules.order files.  Those are removed
 # using awk while concatenating to the final file.

 PHONY += modules
 modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_check modules_prepare
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost

 PHONY += modules_check
 modules_check: modules.order
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh $<

 cmd_modules_order = $(AWK) '!x[$$0]++' $(real-prereqs) > $@

 modules.order: $(subdir-modorder) FORCE
 	$(call if_changed,modules_order)

 targets += modules.order

 # Target to prepare building external modules
 PHONY += modules_prepare
 modules_prepare: prepare
 	$(Q)$(MAKE) $(build)=scripts scripts/module.lds

 # Target to install modules
 PHONY += modules_install
 modules_install: _modinst_ _modinst_post

 PHONY += _modinst_
 _modinst_:
 	@rm -rf $(MODLIB)/kernel
 	@rm -f $(MODLIB)/source
 	@mkdir -p $(MODLIB)/kernel
 	@ln -s $(abspath $(srctree)) $(MODLIB)/source
 	@if [ ! $(objtree) -ef  $(MODLIB)/build ]; then \
 		rm -f $(MODLIB)/build ; \
 		ln -s $(CURDIR) $(MODLIB)/build ; \
 	fi
 	@sed 's:^:kernel/:' modules.order > $(MODLIB)/modules.order
 	@cp -f modules.builtin $(MODLIB)/
 	@cp -f $(objtree)/modules.builtin.modinfo $(MODLIB)/
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst

 # This depmod is only for convenience to give the initial
 # boot a modules.dep even before / is mounted read-write.  However the
 # boot script depmod is the master version.
 PHONY += _modinst_post
 _modinst_post: _modinst_
 	$(call cmd,depmod)

 ifeq ($(CONFIG_MODULE_SIG), y)
 PHONY += modules_sign
 modules_sign:
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modsign
 endif

 else # CONFIG_MODULES

 # Modules not configured
 # ---------------------------------------------------------------------------

 PHONY += modules modules_install
 modules modules_install:
 	@echo >&2
 	@echo >&2 "The present kernel configuration has modules disabled."
 	@echo >&2 "Type 'make config' and enable loadable module support."
 	@echo >&2 "Then build a kernel with module support enabled."
 	@echo >&2
 	@exit 1

 endif # CONFIG_MODULES

 ###
 # Cleaning is done on three levels.
 # make clean     Delete most generated files
 #                Leave enough to build external modules
 # make mrproper  Delete the current configuration, and all generated files
 # make distclean Remove editor backup files, patch leftover files and the like

 # Directories & files removed with 'make clean'
 CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \
 	       modules.builtin modules.builtin.modinfo modules.nsdeps \
 	       compile_commands.json

 # Directories & files removed with 'make mrproper'
 MRPROPER_FILES += include/config include/generated          \
 		  arch/$(SRCARCH)/include/generated .tmp_objdiff \
 		  debian snap tar-install \
 		  .config .config.old .version \
 		  Module.symvers \
 		  signing_key.pem signing_key.priv signing_key.x509	\
 		  x509.genkey extra_certificates signing_key.x509.keyid	\
 		  signing_key.x509.signer vmlinux-gdb.py \
 		  *.spec

 # Directories & files removed with 'make distclean'
 DISTCLEAN_FILES += tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS

 # clean - Delete most, but leave enough to build external modules
 #
 clean: rm-files := $(CLEAN_FILES)

 PHONY += archclean vmlinuxclean

 vmlinuxclean:
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh clean
 	$(Q)$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) clean)

 clean: archclean vmlinuxclean resolve_btfids_clean

 # mrproper - Delete all generated files, including .config
 #
 mrproper: rm-files := $(wildcard $(MRPROPER_FILES))
 mrproper-dirs      := $(addprefix _mrproper_,scripts)

 PHONY += $(mrproper-dirs) mrproper
 $(mrproper-dirs):
 	$(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@)

 mrproper: clean $(mrproper-dirs)
 	$(call cmd,rmfiles)

 # distclean
 #
 distclean: rm-files := $(wildcard $(DISTCLEAN_FILES))

 PHONY += distclean

 distclean: mrproper
 	$(call cmd,rmfiles)
 	@find $(srctree) $(RCS_FIND_IGNORE) \
 		\( -name '*.orig' -o -name '*.rej' -o -name '*~' \
 		-o -name '*.bak' -o -name '#*#' -o -name '*%' \
 		-o -name 'core' \) \
 		-type f -print | xargs rm -f


 # Packaging of the kernel to various formats
 # ---------------------------------------------------------------------------

 %src-pkg: FORCE
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.package $@
 %pkg: include/config/kernel.release FORCE
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.package $@

 # Brief documentation of the typical targets used
 # ---------------------------------------------------------------------------

 boards := $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*_defconfig)
 boards := $(sort $(notdir $(boards)))
 board-dirs := $(dir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*/*_defconfig))
 board-dirs := $(sort $(notdir $(board-dirs:/=)))

 PHONY += help
 help:
 	@echo  'Cleaning targets:'
 	@echo  '  clean		  - Remove most generated files but keep the config and'
 	@echo  '                    enough build support to build external modules'
 	@echo  '  mrproper	  - Remove all generated files + config + various backup files'
 	@echo  '  distclean	  - mrproper + remove editor backup and patch files'
 	@echo  ''
 	@echo  'Configuration targets:'
 	@$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
 	@echo  ''
 	@echo  'Other generic targets:'
 	@echo  '  all		  - Build all targets marked with [*]'
 	@echo  '* vmlinux	  - Build the bare kernel'
 	@echo  '* modules	  - Build all modules'
 	@echo  '  modules_install - Install all modules to INSTALL_MOD_PATH (default: /)'
 	@echo  '  dir/            - Build all files in dir and below'
 	@echo  '  dir/file.[ois]  - Build specified target only'
 	@echo  '  dir/file.ll     - Build the LLVM assembly file'
 	@echo  '                    (requires compiler support for LLVM assembly generation)'
 	@echo  '  dir/file.lst    - Build specified mixed source/assembly target only'
 	@echo  '                    (requires a recent binutils and recent build (System.map))'
 	@echo  '  dir/file.ko     - Build module including final link'
 	@echo  '  modules_prepare - Set up for building external modules'
 	@echo  '  tags/TAGS	  - Generate tags file for editors'
 	@echo  '  cscope	  - Generate cscope index'
 	@echo  '  gtags           - Generate GNU GLOBAL index'
 	@echo  '  kernelrelease	  - Output the release version string (use with make -s)'
 	@echo  '  kernelversion	  - Output the version stored in Makefile (use with make -s)'
 	@echo  '  image_name	  - Output the image name (use with make -s)'
 	@echo  '  headers_install - Install sanitised kernel headers to INSTALL_HDR_PATH'; \
 	 echo  '                    (default: $(INSTALL_HDR_PATH))'; \
 	 echo  ''
 	@echo  'Static analysers:'
 	@echo  '  checkstack      - Generate a list of stack hogs'
 	@echo  '  versioncheck    - Sanity check on version.h usage'
 	@echo  '  includecheck    - Check for duplicate included header files'
 	@echo  '  export_report   - List the usages of all exported symbols'
 	@echo  '  headerdep       - Detect inclusion cycles in headers'
 	@echo  '  coccicheck      - Check with Coccinelle'
 	@echo  '  clang-analyzer  - Check with clang static analyzer'
 	@echo  '  clang-tidy      - Check with clang-tidy'
 	@echo  ''
 	@echo  'Tools:'
 	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'
 	@echo  ''
 	@echo  'Kernel selftest:'
 	@echo  '  kselftest         - Build and run kernel selftest'
 	@echo  '                      Build, install, and boot kernel before'
 	@echo  '                      running kselftest on it'
 	@echo  '                      Run as root for full coverage'
 	@echo  '  kselftest-all     - Build kernel selftest'
 	@echo  '  kselftest-install - Build and install kernel selftest'
 	@echo  '  kselftest-clean   - Remove all generated kselftest files'
 	@echo  '  kselftest-merge   - Merge all the config dependencies of'
 	@echo  '		      kselftest to existing .config.'
 	@echo  ''
 	@$(if $(dtstree), \
 		echo 'Devicetree:'; \
 		echo '* dtbs             - Build device tree blobs for enabled boards'; \
 		echo '  dtbs_install     - Install dtbs to $(INSTALL_DTBS_PATH)'; \
 		echo '  dt_binding_check - Validate device tree binding documents'; \
 		echo '  dtbs_check       - Validate device tree source files';\
 		echo '')

 	@echo 'Userspace tools targets:'
 	@echo '  use "make tools/help"'
 	@echo '  or  "cd tools; make help"'
 	@echo  ''
 	@echo  'Kernel packaging:'
 	@$(MAKE) -f $(srctree)/scripts/Makefile.package help
 	@echo  ''
 	@echo  'Documentation targets:'
 	@$(MAKE) -f $(srctree)/Documentation/Makefile dochelp
 	@echo  ''
 	@echo  'Architecture specific targets ($(SRCARCH)):'
 	@$(if $(archhelp),$(archhelp),\
 		echo '  No architecture specific help defined for $(SRCARCH)')
 	@echo  ''
 	@$(if $(boards), \
 		$(foreach b, $(boards), \
 		printf "  %-27s - Build for %s\\n" $(b) $(subst _defconfig,,$(b));) \
 		echo '')
 	@$(if $(board-dirs), \
 		$(foreach b, $(board-dirs), \
 		printf "  %-16s - Show %s-specific targets\\n" help-$(b) $(b);) \
 		printf "  %-16s - Show all of the above\\n" help-boards; \
 		echo '')

 	@echo  '  make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
 	@echo  '  make V=2   [targets] 2 => give reason for rebuild of target'
 	@echo  '  make O=dir [targets] Locate all output files in "dir", including .config'
 	@echo  '  make C=1   [targets] Check re-compiled c source with $$CHECK'
 	@echo  '                       (sparse by default)'
 	@echo  '  make C=2   [targets] Force check of all c source with $$CHECK'
 	@echo  '  make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections'
 	@echo  '  make W=n   [targets] Enable extra build checks, n=1,2,3 where'
 	@echo  '		1: warnings which may be relevant and do not occur too often'
 	@echo  '		2: warnings which occur quite often but may still be relevant'
 	@echo  '		3: more obscure warnings, can most likely be ignored'
 	@echo  '		Multiple levels can be combined with W=12 or W=123'
 	@echo  ''
 	@echo  'Execute "make" or "make all" to build all targets marked with [*] '
 	@echo  'For further info see the ./README file'


 help-board-dirs := $(addprefix help-,$(board-dirs))

 help-boards: $(help-board-dirs)

 boards-per-dir = $(sort $(notdir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/$*/*_defconfig)))

 $(help-board-dirs): help-%:
 	@echo  'Architecture specific targets ($(SRCARCH) $*):'
 	@$(if $(boards-per-dir), \
 		$(foreach b, $(boards-per-dir), \
 		printf "  %-24s - Build for %s\\n" $*/$(b) $(subst _defconfig,,$(b));) \
 		echo '')


 # Documentation targets
 # ---------------------------------------------------------------------------
 DOC_TARGETS := xmldocs latexdocs pdfdocs htmldocs epubdocs cleandocs \
 	       linkcheckdocs dochelp refcheckdocs
 PHONY += $(DOC_TARGETS)
 $(DOC_TARGETS):
 	$(Q)$(MAKE) $(build)=Documentation $@

 # Misc
 # ---------------------------------------------------------------------------

 PHONY += scripts_gdb
 scripts_gdb: prepare0
 	$(Q)$(MAKE) $(build)=scripts/gdb
 	$(Q)ln -fsn $(abspath $(srctree)/scripts/gdb/vmlinux-gdb.py)

 ifdef CONFIG_GDB_SCRIPTS
 all: scripts_gdb
 endif

 else # KBUILD_EXTMOD

 ###
 # External module support.
 # When building external modules the kernel used as basis is considered
 # read-only, and no consistency checks are made and the make
 # system is not used on the basis kernel. If updates are required
 # in the basis kernel ordinary make commands (without M=...) must
 # be used.
 #
 # The following are the only valid targets when building external
 # modules.
 # make M=dir clean     Delete all automatically generated files
 # make M=dir modules   Make all modules in specified dir
 # make M=dir	       Same as 'make M=dir modules'
 # make M=dir modules_install
 #                      Install the modules built in the module directory
 #                      Assumes install directory is already created

 # We are always building only modules.
 KBUILD_BUILTIN :=
 KBUILD_MODULES := 1

 build-dirs := $(KBUILD_EXTMOD)
 PHONY += modules
 modules: $(MODORDER)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost

 $(MODORDER): descend
 	@:

 PHONY += modules_install
 modules_install: _emodinst_ _emodinst_post

 install-dir := $(if $(INSTALL_MOD_DIR),$(INSTALL_MOD_DIR),extra)
 PHONY += _emodinst_
 _emodinst_:
 	$(Q)mkdir -p $(MODLIB)/$(install-dir)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst

 PHONY += _emodinst_post
 _emodinst_post: _emodinst_
 	$(call cmd,depmod)

 compile_commands.json: $(extmod-prefix)compile_commands.json
 PHONY += compile_commands.json

 clean-dirs := $(KBUILD_EXTMOD)
 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \
 	$(KBUILD_EXTMOD)/compile_commands.json

 PHONY += help
 help:
 	@echo  '  Building external modules.'
 	@echo  '  Syntax: make -C path/to/kernel/src M=$$PWD target'
 	@echo  ''
 	@echo  '  modules         - default target, build the module(s)'
 	@echo  '  modules_install - install the module'
 	@echo  '  clean           - remove generated files in module directory only'
 	@echo  ''

 # no-op for external module builds
 PHONY += prepare modules_prepare

 endif # KBUILD_EXTMOD

 # Single targets
 # ---------------------------------------------------------------------------
 # To build individual files in subdirectories, you can do like this:
 #
 #   make foo/bar/baz.s
 #
 # The supported suffixes for single-target are listed in 'single-targets'
 #
 # To build only under specific subdirectories, you can do like this:
 #
 #   make foo/bar/baz/

 ifdef single-build

 # .ko is special because modpost is needed
 single-ko := $(sort $(filter %.ko, $(MAKECMDGOALS)))
 single-no-ko := $(sort $(patsubst %.ko,%.mod, $(MAKECMDGOALS)))

 $(single-ko): single_modpost
 	@:
 $(single-no-ko): descend
 	@:

 ifeq ($(KBUILD_EXTMOD),)
 # For the single build of in-tree modules, use a temporary file to avoid
 # the situation of modules_install installing an invalid modules.order.
 MODORDER := .modules.tmp
 endif

 PHONY += single_modpost
 single_modpost: $(single-no-ko) modules_prepare
 	$(Q){ $(foreach m, $(single-ko), echo $(extmod-prefix)$m;) } > $(MODORDER)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost

 KBUILD_MODULES := 1

 export KBUILD_SINGLE_TARGETS := $(addprefix $(extmod-prefix), $(single-no-ko))

 # trim unrelated directories
 build-dirs := $(foreach d, $(build-dirs), \
 			$(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d)))

 endif

 ifndef CONFIG_MODULES
 KBUILD_MODULES :=
 endif

 # Handle descending into subdirectories listed in $(build-dirs)
 # Preset locale variables to speed up the build process. Limit locale
 # tweaks to this spot to avoid wrong language settings when running
 # make menuconfig etc.
 # Error messages still appears in the original language
 PHONY += descend $(build-dirs)
 descend: $(build-dirs)
 $(build-dirs): prepare
 	$(Q)$(MAKE) $(build)=$@ \
 	single-build=$(if $(filter-out $@/, $(filter $@/%, $(KBUILD_SINGLE_TARGETS))),1) \
 	need-builtin=1 need-modorder=1

 clean-dirs := $(addprefix _clean_, $(clean-dirs))
 PHONY += $(clean-dirs) clean
 $(clean-dirs):
 	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)

 clean: $(clean-dirs)
 	$(call cmd,rmfiles)
 	@find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
 		\( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '*.ko.*' \
 		-o -name '*.dtb' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
 		-o -name '*.dwo' -o -name '*.lst' \
 		-o -name '*.su' -o -name '*.mod' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*.lex.c' -o -name '*.tab.[ch]' \
 		-o -name '*.asn1.[ch]' \
 		-o -name '*.symtypes' -o -name 'modules.order' \
 		-o -name '.tmp_*.o.*' \
 		-o -name '*.c.[012]*.*' \
 		-o -name '*.ll' \
 		-o -name '*.gcno' \) -type f -print | xargs rm -f

 # Generate tags for editors
 # ---------------------------------------------------------------------------
 quiet_cmd_tags = GEN     $@
       cmd_tags = $(BASH) $(srctree)/scripts/tags.sh $@

 tags TAGS cscope gtags: FORCE
 	$(call cmd,tags)

 # Script to generate missing namespace dependencies
 # ---------------------------------------------------------------------------

 PHONY += nsdeps
 nsdeps: export KBUILD_NSDEPS=1
 nsdeps: modules
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/nsdeps

 # Clang Tooling
 # ---------------------------------------------------------------------------

 quiet_cmd_gen_compile_commands = GEN     $@
       cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))

 $(extmod-prefix)compile_commands.json: scripts/clang-tools/gen_compile_commands.py \
 	$(if $(KBUILD_EXTMOD),,$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)) \
 	$(if $(CONFIG_MODULES), $(MODORDER)) FORCE
 	$(call if_changed,gen_compile_commands)

 targets += $(extmod-prefix)compile_commands.json

 PHONY += clang-tidy clang-analyzer

 ifdef CONFIG_CC_IS_CLANG
 quiet_cmd_clang_tools = CHECK   $<
       cmd_clang_tools = $(PYTHON3) $(srctree)/scripts/clang-tools/run-clang-tools.py $@ $<

 clang-tidy clang-analyzer: $(extmod-prefix)compile_commands.json
 	$(call cmd,clang_tools)
 else
 clang-tidy clang-analyzer:
 	@echo "$@ requires CC=clang" >&2
 	@false
 endif

 # Scripts to check various things for consistency
 # ---------------------------------------------------------------------------

 PHONY += includecheck versioncheck coccicheck export_report

 includecheck:
 	find $(srctree)/* $(RCS_FIND_IGNORE) \
 		-name '*.[hcS]' -type f -print | sort \
 		| xargs $(PERL) -w $(srctree)/scripts/checkincludes.pl

 versioncheck:
 	find $(srctree)/* $(RCS_FIND_IGNORE) \
 		-name '*.[hcS]' -type f -print | sort \
 		| xargs $(PERL) -w $(srctree)/scripts/checkversion.pl

 coccicheck:
 	$(Q)$(BASH) $(srctree)/scripts/$@

 export_report:
 	$(PERL) $(srctree)/scripts/export_report.pl

 PHONY += checkstack kernelrelease kernelversion image_name

 # UML needs a little special treatment here.  It wants to use the host
 # toolchain, so needs $(SUBARCH) passed to checkstack.pl.  Everyone
 # else wants $(ARCH), including people doing cross-builds, which means
 # that $(SUBARCH) doesn't work here.
 ifeq ($(ARCH), um)
 CHECKSTACK_ARCH := $(SUBARCH)
 else
 CHECKSTACK_ARCH := $(ARCH)
 endif
 checkstack:
 	$(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
 	$(PERL) $(srctree)/scripts/checkstack.pl $(CHECKSTACK_ARCH)

 kernelrelease:
 	@echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"

 kernelversion:
 	@echo $(KERNELVERSION)

 image_name:
 	@echo $(KBUILD_IMAGE)

 # Clear a bunch of variables before executing the submake

 ifeq ($(quiet),silent_)
 tools_silent=s
 endif

 tools/: FORCE
 	$(Q)mkdir -p $(objtree)/tools
 	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/

 tools/%: FORCE
 	$(Q)mkdir -p $(objtree)/tools
 	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/ $*

 quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN   $(wildcard $(rm-files)))
       cmd_rmfiles = rm -rf $(rm-files)

 # Run depmod only if we have System.map and depmod is executable
 quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)
       cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \
                    $(KERNELRELEASE)

 # read saved command lines for existing targets
 existing-targets := $(wildcard $(sort $(targets)))

 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)

 endif # config-build
 endif # mixed-build
 endif # need-sub-make

 PHONY += FORCE
 FORCE:

 # Declare the contents of the PHONY variable as phony.  We keep that
 # information in a variable so we can use it in if_changed and friends.
 .PHONY: $(PHONY)