Makefile 53.3 KB
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VERSION = 4
PATCHLEVEL = 0
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SUBLEVEL = 0
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EXTRAVERSION = -rc1
NAME = Hurr durr I'ma sheep
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# *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.

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# Do not use make's built-in rules and variables
# (this increases performance and avoids hard-to-debug behaviour);
MAKEFLAGS += -rR
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# Avoid funny character set dependencies
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unexport LC_ALL
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LC_COLLATE=C
LC_NUMERIC=C
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export LC_COLLATE LC_NUMERIC
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# Avoid interference with shell env settings
unexport GREP_OPTIONS

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# 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.o 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.

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# 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.
#
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# To put more focus on warnings, be less verbose as default
# Use 'make V=1' to see the full commands

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

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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 ($(filter 4.%,$(MAKE_VERSION)),)	# make-4
ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
  quiet=silent_
endif
else					# make-3.8x
ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
  quiet=silent_
endif
endif

export quiet Q KBUILD_VERBOSE

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# kbuild supports saving output files in a separate directory.
# To locate output files in a separate directory two syntaxes are supported.
# In both cases the working directory must be the root of the kernel src.
# 1) O=
# Use "make O=dir/to/store/output/files/"
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#
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# 2) Set KBUILD_OUTPUT
# Set the environment variable KBUILD_OUTPUT to point to the directory
# where the output files shall be placed.
# export KBUILD_OUTPUT=dir/to/store/output/files/
# make
#
# The O= assignment takes precedence over the KBUILD_OUTPUT environment
# variable.

# KBUILD_SRC is set on invocation of make in OBJ directory
# KBUILD_SRC is not intended to be used by the regular user (for now)
ifeq ($(KBUILD_SRC),)

# OK, Make called in directory where kernel src resides
# Do we want to locate output files in a separate directory?
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ifeq ("$(origin O)", "command line")
  KBUILD_OUTPUT := $(O)
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endif

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

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# Cancel implicit rules on top Makefile
$(CURDIR)/Makefile Makefile: ;

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ifneq ($(KBUILD_OUTPUT),)
# Invoke a second make in the output directory, passing relevant variables
# check that the output directory actually exists
saved-output := $(KBUILD_OUTPUT)
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KBUILD_OUTPUT := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) \
								&& /bin/pwd)
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$(if $(KBUILD_OUTPUT),, \
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     $(error failed to create output directory "$(saved-output)"))
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PHONY += $(MAKECMDGOALS) sub-make

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$(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
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	@:
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sub-make: FORCE
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	$(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \
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	-f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS))
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# Leave processing to above invocation of make
skip-makefile := 1
endif # ifneq ($(KBUILD_OUTPUT),)
endif # ifeq ($(KBUILD_SRC),)

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

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# 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

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# 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/sparse.txt" 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 to specify directory of external module to build
# Old syntax make ... SUBDIRS=$PWD is still supported
# Setting the environment variable KBUILD_EXTMOD take precedence
ifdef SUBDIRS
  KBUILD_EXTMOD ?= $(SUBDIRS)
endif

ifeq ("$(origin M)", "command line")
  KBUILD_EXTMOD := $(M)
endif

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

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ifeq ($(KBUILD_SRC),)
        # building in the source tree
        srctree := .
else
        ifeq ($(KBUILD_SRC)/,$(dir $(CURDIR)))
                # building in a subdirectory of the source tree
                srctree := ..
        else
                srctree := $(KBUILD_SRC)
        endif
endif
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objtree		:= .
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src		:= $(srctree)
obj		:= $(objtree)

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VPATH		:= $(srctree)$(if $(KBUILD_EXTMOD),:$(KBUILD_EXTMOD))
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export srctree objtree VPATH
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# SUBARCH tells the usermode build what the underlying arch is.  That is set
# first, and if a usermode build is happening, the "ARCH=um" on the command
# line overrides the setting of ARCH below.  If a native build is happening,
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# then ARCH is assigned, getting whatever value it gets normally, and
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# SUBARCH is subsequently ignored.

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SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x86/ \
				  -e s/sun4u/sparc64/ \
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				  -e s/arm.*/arm/ -e s/sa110/arm/ \
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				  -e s/s390x/s390/ -e s/parisc64/parisc/ \
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				  -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
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				  -e s/sh[234].*/sh/ -e s/aarch64.*/arm64/ )
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# 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.
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# A third alternative is to store a setting in .config so that plain
# "make" in the configured kernel build directory always uses that.
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# Default value for CROSS_COMPILE is not to prefix executables
# Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
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ARCH		?= $(SUBARCH)
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CROSS_COMPILE	?= $(CONFIG_CROSS_COMPILE:"%"=%)
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# Architecture as present in compile.h
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UTS_MACHINE 	:= $(ARCH)
SRCARCH 	:= $(ARCH)
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# Additional ARCH settings for x86
ifeq ($(ARCH),i386)
        SRCARCH := x86
endif
ifeq ($(ARCH),x86_64)
        SRCARCH := x86
endif
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# Additional ARCH settings for sparc
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ifeq ($(ARCH),sparc32)
       SRCARCH := sparc
endif
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ifeq ($(ARCH),sparc64)
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       SRCARCH := sparc
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endif
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# Additional ARCH settings for sh
ifeq ($(ARCH),sh64)
       SRCARCH := sh
endif

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# Additional ARCH settings for tile
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ifeq ($(ARCH),tilepro)
       SRCARCH := tile
endif
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ifeq ($(ARCH),tilegx)
       SRCARCH := tile
endif

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# Where to locate arch specific headers
hdr-arch  := $(SRCARCH)

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KCONFIG_CONFIG	?= .config
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export KCONFIG_CONFIG
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# SHELL used by kbuild
CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
	  else if [ -x /bin/bash ]; then echo /bin/bash; \
	  else echo sh; fi ; fi)

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HOSTCC       = gcc
HOSTCXX      = g++
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HOSTCFLAGS   = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89
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HOSTCXXFLAGS = -O2
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ifeq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1)
HOSTCFLAGS  += -Wno-unused-value -Wno-unused-parameter \
		-Wno-missing-field-initializers -fno-delete-null-pointer-checks
endif

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# Decide whether to build built-in, modular, or both.
# Normally, just do built-in.
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KBUILD_MODULES :=
KBUILD_BUILTIN := 1

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# If we have only "make modules", don't compile built-in objects.
# 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.
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ifeq ($(MAKECMDGOALS),modules)
  KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1)
endif

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# 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
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ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
  KBUILD_MODULES := 1
endif

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

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export KBUILD_MODULES KBUILD_BUILTIN
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export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD

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ifneq ($(CC),)
ifeq ($(shell $(CC) -v 2>&1 | grep -c "clang version"), 1)
COMPILER := clang
else
COMPILER := gcc
endif
export COMPILER
endif
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# Look for make include files relative to root of kernel src
MAKEFLAGS += --include-dir=$(srctree)

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# We need some generic definitions (do not try to remake the file).
$(srctree)/scripts/Kbuild.include: ;
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include $(srctree)/scripts/Kbuild.include
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# Make variables (CC, etc...)
AS		= $(CROSS_COMPILE)as
LD		= $(CROSS_COMPILE)ld
CC		= $(CROSS_COMPILE)gcc
CPP		= $(CC) -E
AR		= $(CROSS_COMPILE)ar
NM		= $(CROSS_COMPILE)nm
STRIP		= $(CROSS_COMPILE)strip
OBJCOPY		= $(CROSS_COMPILE)objcopy
OBJDUMP		= $(CROSS_COMPILE)objdump
AWK		= awk
GENKSYMS	= scripts/genksyms/genksyms
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INSTALLKERNEL  := installkernel
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DEPMOD		= /sbin/depmod
PERL		= perl
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PYTHON		= python
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CHECK		= sparse

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CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
		  -Wbitwise -Wno-return-void $(CF)
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CFLAGS_MODULE   =
AFLAGS_MODULE   =
LDFLAGS_MODULE  =
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CFLAGS_KERNEL	=
AFLAGS_KERNEL	=
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CFLAGS_GCOV	= -fprofile-arcs -ftest-coverage
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# Use USERINCLUDE when you must reference the UAPI directories only.
USERINCLUDE    := \
		-I$(srctree)/arch/$(hdr-arch)/include/uapi \
		-Iarch/$(hdr-arch)/include/generated/uapi \
		-I$(srctree)/include/uapi \
		-Iinclude/generated/uapi \
                -include $(srctree)/include/linux/kconfig.h

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# Use LINUXINCLUDE when you must reference the include/ directory.
# Needed to be compatible with the O= option
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LINUXINCLUDE    := \
		-I$(srctree)/arch/$(hdr-arch)/include \
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		-Iarch/$(hdr-arch)/include/generated/uapi \
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		-Iarch/$(hdr-arch)/include/generated \
		$(if $(KBUILD_SRC), -I$(srctree)/include) \
		-Iinclude \
		$(USERINCLUDE)
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KBUILD_CPPFLAGS := -D__KERNEL__
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KBUILD_CFLAGS   := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
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		   -fno-strict-aliasing -fno-common \
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		   -Werror-implicit-function-declaration \
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		   -Wno-format-security \
		   -std=gnu89
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KBUILD_AFLAGS_KERNEL :=
KBUILD_CFLAGS_KERNEL :=
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KBUILD_AFLAGS   := -D__ASSEMBLY__
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KBUILD_AFLAGS_MODULE  := -DMODULE
KBUILD_CFLAGS_MODULE  := -DMODULE
KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
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# Read KERNELRELEASE from include/config/kernel.release (if it exists)
KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
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KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
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export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
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export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
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export CPP AR NM STRIP OBJCOPY OBJDUMP
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export MAKE AWK GENKSYMS INSTALLKERNEL PERL PYTHON UTS_MACHINE
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export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
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export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
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export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV CFLAGS_KASAN
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export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
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export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
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export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
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export KBUILD_ARFLAGS
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# When compiling out-of-tree modules, put MODVERDIR in the module
# tree rather than in the kernel tree. The kernel tree might
# even be read-only.
export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions

# Files to ignore in find ... statements

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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
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export RCS_TAR_IGNORE := --exclude SCCS --exclude BitKeeper --exclude .svn \
			 --exclude CVS --exclude .pc --exclude .hg --exclude .git
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# ===========================================================================
# Rules shared between *config targets and build targets

# Basic helpers built in scripts/
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PHONY += scripts_basic
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scripts_basic:
	$(Q)$(MAKE) $(build)=scripts/basic
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	$(Q)rm -f .tmp_quiet_recordmcount
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# To avoid any implicit rule to kick in, define an empty command.
scripts/basic/%: scripts_basic ;

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PHONY += outputmakefile
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# outputmakefile generates a Makefile in the output directory, if using a
# separate output directory. This allows convenient use of make in the
# output directory.
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outputmakefile:
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ifneq ($(KBUILD_SRC),)
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	$(Q)ln -fsn $(srctree) source
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	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile \
	    $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)
endif
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# Support for using generic headers in asm-generic
PHONY += asm-generic
asm-generic:
	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \
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	            src=asm obj=arch/$(SRCARCH)/include/generated/asm
	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \
	            src=uapi/asm obj=arch/$(SRCARCH)/include/generated/uapi/asm
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# 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.
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# For example 'make oldconfig all'.
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# Detect when mixed targets is specified, and make a second invocation
# of make so .config is not included in this case either (for *config).

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version_h := include/generated/uapi/linux/version.h
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old_version_h := include/linux/version.h
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no-dot-config-targets := clean mrproper distclean \
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			 cscope gtags TAGS tags help% %docs check% coccicheck \
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			 $(version_h) headers_% archheaders archscripts \
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			 kernelversion %src-pkg
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config-targets := 0
mixed-targets  := 0
dot-config     := 1

ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
	ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
		dot-config := 0
	endif
endif

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

ifeq ($(mixed-targets),1)
# ===========================================================================
# We're called with mixed targets (*config and build targets).
# Handle them one by one.

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PHONY += $(MAKECMDGOALS) __build_one_by_one

$(filter-out __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
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else
ifeq ($(config-targets),1)
# ===========================================================================
# *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'
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include $(srctree)/arch/$(SRCARCH)/Makefile
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export KBUILD_DEFCONFIG KBUILD_KCONFIG
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config: scripts_basic outputmakefile FORCE
	$(Q)$(MAKE) $(build)=scripts/kconfig $@

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

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

ifeq ($(KBUILD_EXTMOD),)
# Additional helpers built in scripts/
# Carefully list dependencies so we do not try to build scripts twice
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# in parallel
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PHONY += scripts
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scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \
	 asm-generic
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	$(Q)$(MAKE) $(build)=$(@)

# Objects we will link into vmlinux / subdirs we need to visit
init-y		:= init/
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drivers-y	:= drivers/ sound/ firmware/
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net-y		:= net/
libs-y		:= lib/
core-y		:= usr/
endif # KBUILD_EXTMOD

ifeq ($(dot-config),1)
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# Read in config
-include include/config/auto.conf
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ifeq ($(KBUILD_EXTMOD),)
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# Read in dependencies to all Kconfig* files, make sure to run
# oldconfig if changes are detected.
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-include include/config/auto.conf.cmd
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# To avoid any implicit rule to kick in, define an empty command
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$(KCONFIG_CONFIG) include/config/auto.conf.cmd: ;
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# If .config is newer than include/config/auto.conf, someone tinkered
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# with it and forgot to run make oldconfig.
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# if auto.conf.cmd is missing then we are probably in a cleaned tree so
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# we execute the config step to be sure to catch updated Kconfig files
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include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd
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	$(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig
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else
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# external modules needs include/generated/autoconf.h and include/config/auto.conf
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# 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:
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	$(Q)test -e include/generated/autoconf.h -a -e $@ || (		\
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	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 ;							\
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	/bin/false)

endif # KBUILD_EXTMOD
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else
# Dummy target needed, because used as prerequisite
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include/config/auto.conf: ;
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endif # $(dot-config)
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# 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
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# Defaults to vmlinux, but the arch makefile usually adds further targets
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all: vmlinux

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include $(srctree)/arch/$(SRCARCH)/Makefile

KBUILD_CFLAGS	+= $(call cc-option,-fno-delete-null-pointer-checks,)

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ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
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KBUILD_CFLAGS	+= -Os $(call cc-disable-warning,maybe-uninitialized,)
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else
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KBUILD_CFLAGS	+= -O2
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endif

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

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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

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ifneq ($(CONFIG_FRAME_WARN),0)
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KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
endif

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# Handle stack protector mode.
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#
# Since kbuild can potentially perform two passes (first with the old
# .config values and then with updated .config values), we cannot error out
# if a desired compiler option is unsupported. If we were to error, kbuild
# could never get to the second pass and actually notice that we changed
# the option to something that was supported.
#
# Additionally, we don't want to fallback and/or silently change which compiler
# flags will be used, since that leads to producing kernels with different
# security feature characteristics depending on the compiler used. ("But I
# selected CC_STACKPROTECTOR_STRONG! Why did it build with _REGULAR?!")
#
# The middle ground is to warn here so that the failed option is obvious, but
# to let the build fail with bad compiler flags so that we can't produce a
# kernel when there is a CONFIG and compiler mismatch.
#
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ifdef CONFIG_CC_STACKPROTECTOR_REGULAR
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  stackp-flag := -fstack-protector
  ifeq ($(call cc-option, $(stackp-flag)),)
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    $(warning Cannot use CONFIG_CC_STACKPROTECTOR_REGULAR: \
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             -fstack-protector not supported by compiler)
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  endif
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else
ifdef CONFIG_CC_STACKPROTECTOR_STRONG
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  stackp-flag := -fstack-protector-strong
  ifeq ($(call cc-option, $(stackp-flag)),)
    $(warning Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: \
	      -fstack-protector-strong not supported by compiler)
  endif
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else
  # Force off for distro compilers that enable stack protector by default.
  stackp-flag := $(call cc-option, -fno-stack-protector)
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endif
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endif
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KBUILD_CFLAGS += $(stackp-flag)
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ifeq ($(COMPILER),clang)
KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,)
KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)
KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
# Quiet clang warning: comparison of unsigned expression < 0 is always false
KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare)
# 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 += $(call cc-option, -mno-global-merge,)
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KBUILD_CFLAGS += $(call cc-option, -fcatch-undefined-behavior)
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else

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# This warning generated too much noise in a regular build.
# Use make W=1 to enable this warning (see scripts/Makefile.build)
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KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
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endif
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ifdef CONFIG_FRAME_POINTER
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KBUILD_CFLAGS	+= -fno-omit-frame-pointer -fno-optimize-sibling-calls
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else
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# 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
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KBUILD_CFLAGS	+= -fomit-frame-pointer
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endif
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endif
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KBUILD_CFLAGS   += $(call cc-option, -fno-var-tracking-assignments)

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ifdef CONFIG_DEBUG_INFO
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ifdef CONFIG_DEBUG_INFO_SPLIT
KBUILD_CFLAGS   += $(call cc-option, -gsplit-dwarf, -g)
else
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KBUILD_CFLAGS	+= -g
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endif
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KBUILD_AFLAGS	+= -Wa,-gdwarf-2
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endif
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ifdef CONFIG_DEBUG_INFO_DWARF4
KBUILD_CFLAGS	+= $(call cc-option, -gdwarf-4,)
endif
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ifdef CONFIG_DEBUG_INFO_REDUCED
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KBUILD_CFLAGS 	+= $(call cc-option, -femit-struct-debug-baseonly) \
		   $(call cc-option,-fno-var-tracking)
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endif

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ifdef CONFIG_FUNCTION_TRACER
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ifndef CC_FLAGS_FTRACE
CC_FLAGS_FTRACE := -pg
endif
export CC_FLAGS_FTRACE
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ifdef CONFIG_HAVE_FENTRY
CC_USING_FENTRY	:= $(call cc-option, -mfentry -DCC_USING_FENTRY)
endif
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KBUILD_CFLAGS	+= $(CC_FLAGS_FTRACE) $(CC_USING_FENTRY)
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KBUILD_AFLAGS	+= $(CC_USING_FENTRY)
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ifdef CONFIG_DYNAMIC_FTRACE
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	ifdef CONFIG_HAVE_C_RECORDMCOUNT
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		BUILD_C_RECORDMCOUNT := y
		export BUILD_C_RECORDMCOUNT
	endif
endif
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endif

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

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

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# warn about C99 declaration after statement
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KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
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# disable pointer signed / unsigned warnings in gcc 4.0
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KBUILD_CFLAGS += $(call cc-disable-warning, pointer-sign)
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# disable invalid "can't wrap" optimizations for signed / pointers
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KBUILD_CFLAGS	+= $(call cc-option,-fno-strict-overflow)
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# conserve stack if available
KBUILD_CFLAGS   += $(call cc-option,-fconserve-stack)

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# disallow errors like 'EXPORT_GPL(foo);' with missing header
KBUILD_CFLAGS   += $(call cc-option,-Werror=implicit-int)

# require functions to have arguments in prototypes, not empty 'int foo()'
KBUILD_CFLAGS   += $(call cc-option,-Werror=strict-prototypes)

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# Prohibit date/time macros, which would make the build non-deterministic
KBUILD_CFLAGS   += $(call cc-option,-Werror=date-time)

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# use the deterministic mode of AR if available
KBUILD_ARFLAGS := $(call ar-option,D)

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# check for 'asm goto'
ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
	KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
endif

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include $(srctree)/scripts/Makefile.kasan
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include $(srctree)/scripts/Makefile.extrawarn

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# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
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KBUILD_CPPFLAGS += $(KCPPFLAGS)
KBUILD_AFLAGS += $(KAFLAGS)
KBUILD_CFLAGS += $(KCFLAGS)
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# Use --build-id when available.
LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
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			      $(call cc-ldoption, -Wl$(comma)--build-id,))
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KBUILD_LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
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LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)

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

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# Default kernel image to build when no specific target is given.
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# KBUILD_IMAGE may be overruled on the command line or
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# 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

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#
# 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)

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

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

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

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# 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 = gzip -n
  endif # CONFIG_MODULE_COMPRESS_GZIP
  ifdef CONFIG_MODULE_COMPRESS_XZ
    mod_compress_cmd = xz
  endif # CONFIG_MODULE_COMPRESS_XZ
endif # CONFIG_MODULE_COMPRESS
export mod_compress_cmd

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# Select initial ramdisk compression format, default is gzip(1).
# This shall be used by the dracut(8) tool while creating an initramfs image.
#
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INITRD_COMPRESS-y                  := gzip
INITRD_COMPRESS-$(CONFIG_RD_BZIP2) := bzip2
INITRD_COMPRESS-$(CONFIG_RD_LZMA)  := lzma
INITRD_COMPRESS-$(CONFIG_RD_XZ)    := xz
INITRD_COMPRESS-$(CONFIG_RD_LZO)   := lzo
INITRD_COMPRESS-$(CONFIG_RD_LZ4)   := lz4
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# do not export INITRD_COMPRESS, since we didn't actually
# choose a sane default compression above.
# export INITRD_COMPRESS := $(INITRD_COMPRESS-y)
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ifdef CONFIG_MODULE_SIG_ALL
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MODSECKEY = ./signing_key.priv
MODPUBKEY = ./signing_key.x509
export MODPUBKEY
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mod_sign_cmd = perl $(srctree)/scripts/sign-file $(CONFIG_MODULE_SIG_HASH) $(MODSECKEY) $(MODPUBKEY)
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else
mod_sign_cmd = true
endif
export mod_sign_cmd


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ifeq ($(KBUILD_EXTMOD),)
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core-y		+= kernel/ mm/ fs/ ipc/ security/ crypto/ block/
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vmlinux-dirs	:= $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
		     $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
		     $(net-y) $(net-m) $(libs-y) $(libs-m)))

vmlinux-alldirs	:= $(sort $(vmlinux-dirs) $(patsubst %/,%,$(filter %/, \
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		     $(init-) $(core-) $(drivers-) $(net-) $(libs-))))
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init-y		:= $(patsubst %/, %/built-in.o, $(init-y))
core-y		:= $(patsubst %/, %/built-in.o, $(core-y))
drivers-y	:= $(patsubst %/, %/built-in.o, $(drivers-y))
net-y		:= $(patsubst %/, %/built-in.o, $(net-y))
libs-y1		:= $(patsubst %/, %/lib.a, $(libs-y))
libs-y2		:= $(patsubst %/, %/built-in.o, $(libs-y))
libs-y		:= $(libs-y1) $(libs-y2)

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# Externally visible symbols (used by link-vmlinux.sh)
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export KBUILD_VMLINUX_INIT := $(head-y) $(init-y)
export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y) $(drivers-y) $(net-y)
export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
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export LDFLAGS_vmlinux
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# used by scripts/pacmage/Makefile
export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Documentation include samples scripts tools virt)
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vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN)
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# Final link of vmlinux
      cmd_link-vmlinux = $(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux)
quiet_cmd_link-vmlinux = LINK    $@
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# Include targets which we want to
# execute if the rest of the kernel build went well.
vmlinux: scripts/link-vmlinux.sh $(vmlinux-deps) FORCE
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ifdef CONFIG_HEADERS_CHECK
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	$(Q)$(MAKE) -f $(srctree)/Makefile headers_check
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endif
ifdef CONFIG_SAMPLES
	$(Q)$(MAKE) $(build)=samples
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endif
ifdef CONFIG_BUILD_DOCSRC
	$(Q)$(MAKE) $(build)=Documentation
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endif
ifdef CONFIG_GDB_SCRIPTS
	$(Q)ln -fsn `cd $(srctree) && /bin/pwd`/scripts/gdb/vmlinux-gdb.py
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endif
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	+$(call if_changed,link-vmlinux)
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# The actual objects are generated when descending,
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# make sure no implicit rule kicks in
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$(sort $(vmlinux-deps)): $(vmlinux-dirs) ;
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# Handle descending into subdirectories listed in $(vmlinux-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

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PHONY += $(vmlinux-dirs)
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$(vmlinux-dirs): prepare scripts
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	$(Q)$(MAKE) $(build)=$@

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define filechk_kernel.release
	echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
endef

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# Store (new) KERNELRELEASE string in include/config/kernel.release
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include/config/kernel.release: include/config/auto.conf FORCE
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	$(call filechk,kernel.release)
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# Things we need to do before we recursively start building the kernel
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# 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.
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# Listed in dependency order
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PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3
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# prepare3 is used to check if we are building in a separate output directory,
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# and if so do:
# 1) Check that make has not been executed in the kernel src $(srctree)
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prepare3: include/config/kernel.release
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ifneq ($(KBUILD_SRC),)
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	@$(kecho) '  Using $(srctree) as source for kernel'
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	$(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \
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		echo >&2 "  $(srctree) is not clean, please run 'make mrproper'"; \
		echo >&2 "  in the '$(srctree)' directory.";\
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		/bin/false; \
	fi;
endif

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# prepare2 creates a makefile if using a separate output directory
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prepare2: prepare3 outputmakefile asm-generic
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prepare1: prepare2 $(version_h) include/generated/utsrelease.h \
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                   include/config/auto.conf
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	$(cmd_crmodverdir)
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archprepare: archheaders archscripts prepare1 scripts_basic
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prepare0: archprepare FORCE
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	$(Q)$(MAKE) $(build)=.
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# All the preparing..
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prepare: prepare0
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# 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