Makefile

# SPDX-License-Identifier: GPL-2.0
VERSION = 5
PATCHLEVEL = 11
SUBLEVEL = 0
EXTRAVERSION = -rc2
NAME = Kleptomaniac Octopus

# *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
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)
quiet_cmd_syncconfig = SYNC    $@
      cmd_syncconfig = $(MAKE) -f $(srctree)/Makefile syncconfig

%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h: $(KCONFIG_CONFIG)
	+$(call cmd,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

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

# 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

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

# 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_USE_CC
  CC_FLAGS_FTRACE	+= -mrecord-mcount
  ifdef CONFIG_HAVE_NOP_MCOUNT
    ifeq ($(call cc-option-yn, -mnop-mcount),y)
      CC_FLAGS_FTRACE	+= -mnop-mcount
      CC_FLAGS_USING	+= -DCC_USING_NOP_MCOUNT
    endif
  endif
endif
ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
  ifdef CONFIG_HAVE_C_RECORDMCOUNT
    BUILD_C_RECORDMCOUNT := y
    export BUILD_C_RECORDMCOUNT
  endif
endif
ifdef CONFIG_HAVE_FENTRY
  ifeq ($(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)
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_LTO_CLANG
ifdef CONFIG_LTO_CLANG_THIN
CC_FLAGS_LTO	:= -flto=thin -fsplit-lto-unit
KBUILD_LDFLAGS	+= --thinlto-cache-dir=$(extmod-prefix).thinlto-cache
else
CC_FLAGS_LTO	:= -flto
endif
CC_FLAGS_LTO	+= -fvisibility=hidden

# Limit inlining across translation units to reduce binary size
KBUILD_LDFLAGS += -mllvm -import-instr-limit=5
endif

ifdef CONFIG_LTO
KBUILD_CFLAGS	+= $(CC_FLAGS_LTO)
export CC_FLAGS_LTO
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)/=)

# ensure -fcf-protection is disabled when using retpoline as it is
# incompatible with -mindirect-branch=thunk-extern
ifdef CONFIG_RETPOLINE
KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
endif

# 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
endif