60 KiB
SPDX-License-Identifier: GPL-2.0
VERSION = 5 PATCHLEVEL = 2 SUBLEVEL = 60 EXTRAVERSION = NAME = Bobtail Squid
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.
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 $@ :<
If KBUILD_VERBOSE equals 0 then the above command will be hidden.
If KBUILD_VERBOSE equals 1 then the above command is displayed.
To put more focus on warnings, be less verbose as default
Use 'make V=1' to see the full commands
ifeq ("$(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
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.
$(lastword $(MAKEFILE_LIST)): ; endif
export abs_srctree abs_objtree export sub_make_done := 1
ifeq ($(need-sub-make),1)
PHONY += $(MAKECMDGOALS) sub-make
$(filter-out _all sub-make $(lastword $(MAKEFILE_LIST)), $(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 = $(C) endif ifndef KBUILD_CHECKSRC KBUILD_CHECKSRC = 0 endif
Use make M=dir to specify directory of external module to build
Old syntax make ... SUBDIRS=$PWD is still supported
Setting the environment variable KBUILD_EXTMOD take precedence
ifdef SUBDIRS $(warning ================= WARNING ================) $(warning 'SUBDIRS' will be removed after Linux 5.3) $(warning Please use 'M=' or 'KBUILD_EXTMOD' instead) $(warning ==========================================) KBUILD_EXTMOD ?= $(SUBDIRS) endif
ifeq ("$(origin M)", "command line") KBUILD_EXTMOD := $(M) endif
ifeq ($(abs_srctree),$(abs_objtree)) # building in the source tree srctree := . else ifeq ($(abs_srctree)/,$(dir $(abs_objtree))) # building in a subdirectory of the source tree srctree := .. else srctree := $(abs_srctree) endif
# TODO:
# KBUILD_SRC is only used to distinguish in-tree/out-of-tree build.
# Replace it with $(srctree) or something.
KBUILD_SRC := $(abs_srctree)
endif
export KBUILD_CHECKSRC KBUILD_EXTMOD KBUILD_SRC
objtree := . src := $(srctree) obj := $(objtree)
VPATH := $(srctree)
export 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_% archheaders archscripts
%asm-generic kernelversion %src-pkg
no-sync-config-targets := $(no-dot-config-targets) install %install
kernelrelease
config-targets := 0 mixed-targets := 0 dot-config := 1 may-sync-config := 1
ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),) ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),) dot-config := 0 endif endif
ifneq ($(filter $(no-sync-config-targets), $(MAKECMDGOALS)),) ifeq ($(filter-out $(no-sync-config-targets), $(MAKECMDGOALS)),) may-sync-config := 0 endif endif
ifneq ($(KBUILD_EXTMOD),) may-sync-config := 0 endif
ifeq ($(KBUILD_EXTMOD),) ifneq ($(filter config %config,$(MAKECMDGOALS)),) config-targets := 1 ifneq ($(words $(MAKECMDGOALS)),1) mixed-targets := 1 endif endif endif
For "make -j clean all", "make -j mrproper defconfig all", etc.
ifneq ($(filter $(clean-targets),$(MAKECMDGOALS)),) ifneq ($(filter-out $(clean-targets),$(MAKECMDGOALS)),) mixed-targets := 1 endif endif
install and modules_install need also be processed one by one
ifneq ($(filter install,$(MAKECMDGOALS)),) ifneq ($(filter modules_install,$(MAKECMDGOALS)),) mixed-targets := 1 endif endif
ifeq ($(mixed-targets),1)
===========================================================================
We're called with mixed targets (*config and build targets).
Handle them one by one.
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 $$i;
done
else
include scripts/Kbuild.include
Read KERNELRELEASE from include/config/kernel.release (if it exists)
KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null) KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION) export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
include scripts/subarch.include
Cross compiling and selecting different set of gcc/bin-utils
---------------------------------------------------------------------------
When performing cross compilation for other architectures ARCH shall be set
to the target architecture. (See arch/* for the possibilities).
ARCH can be set during invocation of make:
make ARCH=ia64
Another way is to have ARCH set in the environment.
The default ARCH is the host where make is executed.
CROSS_COMPILE specify the prefix used for all executables used
during compilation. Only gcc and related bin-utils executables
are prefixed with $(CROSS_COMPILE).
CROSS_COMPILE can be set on the command line
make CROSS_COMPILE=ia64-linux-
Alternatively CROSS_COMPILE can be set in the environment.
Default value for CROSS_COMPILE is not to prefix executables
Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
ARCH ?= $(SUBARCH)
Architecture as present in compile.h
UTS_MACHINE := $(ARCH) SRCARCH := $(ARCH)
Additional ARCH settings for x86
ifeq ($(ARCH),i386) SRCARCH := x86 endif ifeq ($(ARCH),x86_64) SRCARCH := x86 endif
Additional ARCH settings for sparc
ifeq ($(ARCH),sparc32) SRCARCH := sparc endif ifeq ($(ARCH),sparc64) SRCARCH := sparc endif
Additional ARCH settings for sh
ifeq ($(ARCH),sh64) SRCARCH := sh endif
KCONFIG_CONFIG ?= .config export KCONFIG_CONFIG
SHELL used by kbuild
CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH;
else if [ -x /bin/bash ]; then echo /bin/bash;
else echo sh; fi ; fi)
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)
HOSTCC = gcc
HOSTCXX = g++
KBUILD_HOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2
-fomit-frame-pointer -std=gnu89 $(HOST_LFS_CFLAGS)
$(HOSTCFLAGS)
KBUILD_HOSTCXXFLAGS := -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
KBUILD_HOSTLDFLAGS := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
KBUILD_HOSTLDLIBS := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
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 PAHOLE = pahole LEX = flex YACC = bison AWK = awk INSTALLKERNEL := installkernel DEPMOD = /sbin/depmod PERL = perl PYTHON = python PYTHON2 = python2 PYTHON3 = python3 CHECK = sparse
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 $(filter .,$(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
-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 := -T $(srctree)/scripts/module-common.lds
KBUILD_LDFLAGS :=
GCC_PLUGINS_CFLAGS :=
CLANG_FLAGS :=
export ARCH SRCARCH CONFIG_SHELL HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC export CPP AR NM STRIP OBJCOPY OBJDUMP PAHOLE KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS export MAKE LEX YACC AWK INSTALLKERNEL PERL PYTHON PYTHON2 PYTHON3 UTS_MACHINE export HOSTCXX KBUILD_HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL export KBUILD_ARFLAGS
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
export RCS_FIND_IGNORE := ( -name SCCS -o -name BitKeeper -o -name .svn -o
-name CVS -o -name .pc -o -name .hg -o -name .git -o -name meta )
-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
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:
ifneq ($(srctree),.)
$(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 CLANG_FLAGS += -no-integrated-as 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)
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'
include arch/$(SRCARCH)/Makefile export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT
config: scripts_basic outputmakefile FORCE $(Q)$(MAKE) $(build)=scripts/kconfig $@
%config: scripts_basic outputmakefile FORCE $(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.
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 modules", compile modules
in addition to whatever we do anyway.
Just "make" or "make all" shall build modules as well
ifneq ($(filter all _all modules,$(MAKECMDGOALS)),) KBUILD_MODULES := 1 endif
ifeq ($(MAKECMDGOALS),) KBUILD_MODULES := 1 endif
export KBUILD_MODULES KBUILD_BUILTIN
ifeq ($(dot-config),1) include include/config/auto.conf endif
ifeq ($(KBUILD_EXTMOD),)
Objects we will link into vmlinux / subdirs we need to visit
init-y := init/ drivers-y := drivers/ sound/ drivers-$(CONFIG_SAMPLES) += samples/ net-y := net/ libs-y := lib/ core-y := usr/ virt-y := virt/ 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
The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
values of the respective KBUILD_* variables
ARCH_CPPFLAGS := ARCH_AFLAGS := ARCH_CFLAGS := include arch/$(SRCARCH)/Makefile
ifeq ($(dot-config),1) ifeq ($(may-sync-config),1)
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.
%/auto.conf %/auto.conf.cmd %/tristate.conf: $(KCONFIG_CONFIG) $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig else
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 # $(dot-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_SIZE KBUILD_CFLAGS += -Os else KBUILD_CFLAGS += -O2 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)
include scripts/Makefile.kcov include scripts/Makefile.gcc-plugins
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 += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN}) endif
stackp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -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
Quiet clang warning: comparison of unsigned expression < 0 is always false
KBUILD_CFLAGS += -Wno-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 += -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 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 pattern, if desired.
ifdef CONFIG_INIT_STACK_ALL KBUILD_CFLAGS += -ftrivial-auto-var-init=pattern endif
DEBUG_CFLAGS := $(call cc-option, -fno-var-tracking-assignments)
ifdef CONFIG_DEBUG_INFO ifdef CONFIG_DEBUG_INFO_SPLIT DEBUG_CFLAGS += -gsplit-dwarf else DEBUG_CFLAGS += -g endif 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
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_LIVEPATCH KBUILD_CFLAGS += $(call cc-option, -flive-patching=inline-clone) 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 += $(call cc-option,-fno-strict-overflow)
clang sets -fmerge-all-constants by default as optimization, but this
is non-conforming behavior for C and in fact breaks the kernel, so we
need to disable it here generally.
KBUILD_CFLAGS += $(call cc-option,-fno-merge-all-constants)
for gcc -fno-merge-all-constants disables everything, but it is fine
to have actual conforming behavior enabled.
KBUILD_CFLAGS += $(call cc-option,-fmerge-constants)
Make sure -fstack-check isn't enabled (like gentoo apparently did)
KBUILD_CFLAGS += $(call cc-option,-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 += $(call cc-option,-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_CFLAGS += $(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
use the deterministic mode of AR if available
KBUILD_ARFLAGS := $(call ar-option,D)
include scripts/Makefile.kasan include scripts/Makefile.extrawarn include scripts/Makefile.ubsan
Add any arch overrides and user supplied CPPFLAGS, AFLAGS and CFLAGS as the
last assignments
KBUILD_CPPFLAGS += $(ARCH_CPPFLAGS) $(KCPPFLAGS) KBUILD_AFLAGS += $(ARCH_AFLAGS) $(KAFLAGS) KBUILD_CFLAGS += $(ARCH_CFLAGS) $(KCFLAGS)
Use --build-id when available.
LDFLAGS_BUILD_ID := $(call ld-option, --build-id) KBUILD_LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID) LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)
ifeq ($(CONFIG_STRIP_ASM_SYMS),y) LDFLAGS_vmlinux += $(call ld-option, -X,) endif
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 = gzip -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)
ifdef CONFIG_STACK_VALIDATION
has_libelf := $(call try-run,
echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
ifeq ($(has_libelf),1)
objtool_target := tools/objtool FORCE
else
SKIP_STACK_VALIDATION := 1
export SKIP_STACK_VALIDATION
endif
endif
PHONY += prepare0
ifeq ($(KBUILD_EXTMOD),) core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/
vmlinux-dirs := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m)
$(core-y) $(core-m) $(drivers-y) $(drivers-m)
$(net-y) $(net-m) $(libs-y) $(libs-m) $(virt-y)))
vmlinux-alldirs := $(sort $(vmlinux-dirs) Documentation
$(patsubst %/,%,$(filter %/, $(init-) $(core-)
$(drivers-) $(net-) $(libs-) $(virt-))))
init-y := $(patsubst %/, %/built-in.a, $(init-y)) core-y := $(patsubst %/, %/built-in.a, $(core-y)) drivers-y := $(patsubst %/, %/built-in.a, $(drivers-y)) net-y := $(patsubst %/, %/built-in.a, $(net-y)) libs-y1 := $(patsubst %/, %/lib.a, $(libs-y)) libs-y2 := $(patsubst %/, %/built-in.a, $(filter-out %.a, $(libs-y))) virt-y := $(patsubst %/, %/built-in.a, $(virt-y))
Externally visible symbols (used by link-vmlinux.sh)
export KBUILD_VMLINUX_OBJS := $(head-y) $(init-y) $(core-y) $(libs-y2)
$(drivers-y) $(net-y) $(virt-y)
export KBUILD_VMLINUX_LIBS := $(libs-y1)
export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds
export LDFLAGS_vmlinux
used by scripts/package/Makefile
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
autoksyms_recursive: $(vmlinux-deps)
ifdef CONFIG_TRIM_UNUSED_KSYMS
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh
"$(MAKE) -f $(srctree)/Makefile vmlinux"
endif
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)
ifdef CONFIG_TRIM_UNUSED_KSYMS KBUILD_MODULES := 1 endif
autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h)
$(autoksyms_h): $(Q)mkdir -p $(dir $@) $(Q)touch $@
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
Some samples need headers_install.
samples: headers_install
The actual objects are generated when descending,
make sure no implicit rule kicks in
$(sort $(vmlinux-deps)): $(vmlinux-dirs) ;
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
PHONY += $(vmlinux-dirs) $(vmlinux-dirs): prepare $(Q)$(MAKE) $(build)=$@ need-builtin=1
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 prepare1 prepare3
prepare3 is used to check if we are building in a separate output directory,
and if so do:
1) Check that make has not been executed in the kernel src $(srctree)
prepare3: include/config/kernel.release
ifneq ($(srctree),.)
@$(kecho) ' Using $(srctree) as source for kernel'
$(Q)if [ -f $(srctree)/.config -o
-d $(srctree)/include/config -o
-d $(srctree)/arch/$(SRCARCH)/include/generated ]; then
echo >&2 " $(srctree) is not clean, please run 'make ARCH=$(ARCH) mrproper'";
echo >&2 " in the '$(srctree)' directory.";
/bin/false;
fi;
endif
prepare1: prepare3 outputmakefile asm-generic $(version_h) $(autoksyms_h)
include/generated/utsrelease.h
$(cmd_crmodverdir)
archprepare: archheaders archscripts prepare1 scripts
prepare0: archprepare $(Q)$(MAKE) $(build)=scripts/mod $(Q)$(MAKE) $(build)=.
All the preparing..
prepare: prepare0 prepare-objtool
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-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
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
echo #define LINUX_VERSION_CODE $(shell
expr $(VERSION) * 65536 + 0$(PATCHLEVEL) * 256 + 0$(SUBLEVEL));
echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))'
endef
$(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 = $(objtree)/usr
If we do an all arch process set dst to include/arch-$(SRCARCH)
hdr-dst = $(if $(KBUILD_HEADERS), dst=include/arch-$(SRCARCH), dst=include)
PHONY += archheaders archscripts
PHONY += __headers __headers: $(version_h) scripts_basic uapi-asm-generic archheaders archscripts $(Q)$(MAKE) $(build)=scripts build_unifdef
PHONY += headers_install_all headers_install_all: $(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh install
PHONY += headers_install
headers_install: __headers
$(if $(wildcard $(srctree)/arch/$(SRCARCH)/include/uapi/asm/Kbuild),,
$(error Headers not exportable for the $(SRCARCH) architecture))
$(Q)$(MAKE) $(hdr-inst)=include/uapi dst=include
$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi $(hdr-dst)
PHONY += headers_check_all headers_check_all: headers_install_all $(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh check
PHONY += headers_check headers_check: headers_install $(Q)$(MAKE) $(hdr-inst)=include/uapi dst=include HDRCHECK=1 $(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi $(hdr-dst) HDRCHECK=1
ifdef CONFIG_HEADERS_CHECK all: headers_check endif
---------------------------------------------------------------------------
Kernel selftest
PHONY += kselftest kselftest: $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests run_tests
PHONY += kselftest-clean kselftest-clean: $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests clean
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: prepare3 scripts_dtc $(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
PHONY += dtbs dtbs_install dtbs_check dtbs: prepare3 scripts_dtc $(Q)$(MAKE) $(build)=$(dtstree)
ifneq ($(filter dtbs_check, $(MAKECMDGOALS)),) dtbs: dt_binding_check endif
dtbs_check: export CHECK_DTBS=1 dtbs_check: dtbs
dtbs_install: $(Q)$(MAKE) $(dtbinst)=$(dtstree)
ifdef CONFIG_OF_EARLY_FLATTREE all: dtbs endif
endif
PHONY += scripts_dtc scripts_dtc: scripts_basic $(Q)$(MAKE) $(build)=scripts/dtc
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: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin $(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order @$(kecho) ' Building modules, stage 2.'; $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost $(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh
modules.builtin: $(vmlinux-dirs:%=%/modules.builtin) $(Q)$(AWK) '!x[$$0]++' $^ > $(objtree)/modules.builtin
%/modules.builtin: include/config/auto.conf include/config/tristate.conf $(Q)$(MAKE) $(modbuiltin)=$*
Target to prepare building external modules
PHONY += modules_prepare modules_prepare: prepare
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
@cp -f $(objtree)/modules.order $(MODLIB)/
@cp -f $(objtree)/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_DIRS += $(MODVERDIR) include/ksym CLEAN_FILES += modules.builtin.modinfo
Directories & files removed with 'make mrproper'
MRPROPER_DIRS += include/config usr/include include/generated
arch/$(SRCARCH)/include/generated .tmp_objdiff
MRPROPER_FILES += .config .config.old .version
Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
signing_key.pem signing_key.priv signing_key.x509
x509.genkey extra_certificates signing_key.x509.keyid
signing_key.x509.signer vmlinux-gdb.py
clean - Delete most, but leave enough to build external modules
clean: rm-dirs := $(CLEAN_DIRS) clean: rm-files := $(CLEAN_FILES) clean-dirs := $(addprefix clean, . $(vmlinux-alldirs))
PHONY += $(clean-dirs) clean archclean vmlinuxclean $(clean-dirs): $(Q)$(MAKE) $(clean)=$(patsubst clean%,%,$@)
vmlinuxclean: $(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh clean $(Q)$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) clean)
clean: archclean vmlinuxclean
mrproper - Delete all generated files, including .config
mrproper: rm-dirs := $(wildcard $(MRPROPER_DIRS)) 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,rmdirs) $(call cmd,rmfiles)
distclean
PHONY += distclean
distclean: mrproper
@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
---------------------------------------------------------------------------
package-dir := scripts/package
%src-pkg: FORCE $(Q)$(MAKE) $(build)=$(package-dir) $@ %pkg: include/config/kernel.release FORCE $(Q)$(MAKE) $(build)=$(package-dir) $@
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: $(INSTALL_HDR_PATH))';
echo ''
@echo 'Static analysers:'
@echo ' checkstack - Generate a list of stack hogs'
@echo ' namespacecheck - Name space analysis on compiled kernel'
@echo ' versioncheck - Sanity check on version.h usage'
@echo ' includecheck - Check for duplicate included header files'
@echo ' export_report - List the usages of all exported symbols'
@echo ' headers_check - Sanity check on exported headers'
@echo ' headerdep - Detect inclusion cycles in headers'
@echo ' coccicheck - Check with Coccinelle'
@echo ''
@echo 'Kernel selftest:'
@echo ' kselftest - Build and run kernel selftest (run as root)'
@echo ' Build, install, and boot kernel before'
@echo ' running kselftest on it'
@echo ' kselftest-clean - Remove all generated kselftest files'
@echo ' kselftest-merge - Merge all the config dependencies of kselftest to existing'
@echo ' .config.'
@echo ''
@$(if $(dtstree),
echo 'Devicetree:';
echo '* dtbs - Build device tree blobs for enabled boards';
echo ' dtbs_install - Install dtbs to $(INSTALL_DTBS_PATH)';
echo '')
@echo 'Userspace tools targets:'
@echo ' use "make tools/help"'
@echo ' or "cd tools; make help"'
@echo ''
@echo 'Kernel packaging:'
@$(MAKE) $(build)=$(package-dir) 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 " %-24s - 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 $$CHECK (sparse by default)'
@echo ' make C=2 [targets] Force check of all c source with $$CHECK'
@echo ' make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections'
@echo ' make W=n [targets] Enable extra gcc 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): scripts_basic FORCE
$(Q)$(MAKE) $(build)=Documentation $@
Misc
---------------------------------------------------------------------------
PHONY += scripts_gdb scripts_gdb: prepare $(Q)$(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 modules
KBUILD_MODULES := 1
PHONY += $(objtree)/Module.symvers
$(objtree)/Module.symvers:
@test -e $(objtree)/Module.symvers || (
echo;
echo " WARNING: Symbol version dump $(objtree)/Module.symvers";
echo " is missing; modules will have no dependencies and modversions.";
echo )
module-dirs := $(addprefix module,$(KBUILD_EXTMOD)) PHONY += $(module-dirs) modules $(module-dirs): prepare $(objtree)/Module.symvers $(Q)$(MAKE) $(build)=$(patsubst module%,%,$@)
modules: $(module-dirs) @$(kecho) ' Building modules, stage 2.'; $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
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)
clean-dirs := $(addprefix clean,$(KBUILD_EXTMOD))
PHONY += $(clean-dirs) clean $(clean-dirs): $(Q)$(MAKE) $(clean)=$(patsubst clean%,%,$@)
clean: rm-dirs := $(MODVERDIR) clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
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 ''
PHONY += prepare prepare: $(cmd_crmodverdir) endif # KBUILD_EXTMOD
clean: $(clean-dirs)
$(call cmd,rmdirs)
$(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 '..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 modules.builtin -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 = $(CONFIG_SHELL) $(srctree)/scripts/tags.sh $@
tags TAGS cscope gtags: FORCE $(call cmd,tags)
Scripts to check various things for consistency
---------------------------------------------------------------------------
PHONY += includecheck versioncheck coccicheck namespacecheck 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)$(CONFIG_SHELL) $(srctree)/scripts/$@
namespacecheck: $(PERL) $(srctree)/scripts/namespace.pl
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) $(src)/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 $(src)/tools/
tools/%: FORCE $(Q)mkdir -p $(objtree)/tools $(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(src)/tools/ $*
Single targets
---------------------------------------------------------------------------
Single targets are compatible with:
- build with mixed source and output
- build with separate output dir 'make O=...'
- external modules
target-dir => where to store outputfile
build-dir => directory in kernel source tree to use
build-target = $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD)/)$@ build-dir = $(patsubst %/,%,$(dir $(build-target)))
%.i: prepare FORCE $(Q)$(MAKE) $(build)=$(build-dir) $(build-target) %.ll: prepare FORCE $(Q)$(MAKE) $(build)=$(build-dir) $(build-target) %.lst: prepare FORCE $(Q)$(MAKE) $(build)=$(build-dir) $(build-target) %.o: prepare FORCE $(Q)$(MAKE) $(build)=$(build-dir) $(build-target) %.s: prepare FORCE $(Q)$(MAKE) $(build)=$(build-dir) $(build-target) %.symtypes: prepare FORCE $(Q)$(MAKE) $(build)=$(build-dir) $(build-target) %.ko: %.o $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
Modules
PHONY += / /: ./
Make sure the latest headers are built for Documentation
Documentation/ samples/: headers_install %/: prepare FORCE $(Q)$(MAKE) KBUILD_MODULES=1 $(build)=$(build-dir)
FIXME Should go into a make.lib or something
===========================================================================
quiet_cmd_rmdirs = $(if $(wildcard $(rm-dirs)),CLEAN $(wildcard $(rm-dirs))) cmd_rmdirs = rm -rf $(rm-dirs)
quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN $(wildcard $(rm-files))) cmd_rmfiles = rm -f $(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)
Create temporary dir for module support files
clean it up only when building all modules
cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR)
$(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)
read saved command lines for existing targets
existing-targets := $(wildcard $(sort $(targets)))
-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
endif # ifeq ($(config-targets),1) endif # ifeq ($(mixed-targets),1) 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)