8 # To see a list of typical targets execute "make help"
9 # More info can be located in ./README
10 # Comments in this file are targeted only to the developer, do not
11 # expect to learn how to build the kernel reading this file.
13 # o Do not use make's built-in rules and variables
14 # (this increases performance and avoids hard-to-debug behaviour);
15 # o Look for make include files relative to root of kernel src
16 MAKEFLAGS
+= -rR
--include-dir
=$(CURDIR
)
18 # Avoid funny character set dependencies
22 export LC_COLLATE LC_NUMERIC
24 # Avoid interference with shell env settings
27 # We are using a recursive build, so we need to do a little thinking
28 # to get the ordering right.
30 # Most importantly: sub-Makefiles should only ever modify files in
31 # their own directory. If in some directory we have a dependency on
32 # a file in another dir (which doesn't happen often, but it's often
33 # unavoidable when linking the built-in.o targets which finally
34 # turn into vmlinux), we will call a sub make in that other dir, and
35 # after that we are sure that everything which is in that other dir
38 # The only cases where we need to modify files which have global
39 # effects are thus separated out and done before the recursive
40 # descending is started. They are now explicitly listed as the
44 # ---------------------------------------------------------------------------
46 # Normally, we echo the whole command before executing it. By making
47 # that echo $($(quiet)$(cmd)), we now have the possibility to set
48 # $(quiet) to choose other forms of output instead, e.g.
50 # quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
51 # cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
53 # If $(quiet) is empty, the whole command will be printed.
54 # If it is set to "quiet_", only the short version will be printed.
55 # If it is set to "silent_", nothing will be printed at all, since
56 # the variable $(silent_cmd_cc_o_c) doesn't exist.
58 # A simple variant is to prefix commands with $(Q) - that's useful
59 # for commands that shall be hidden in non-verbose mode.
63 # If KBUILD_VERBOSE equals 0 then the above command will be hidden.
64 # If KBUILD_VERBOSE equals 1 then the above command is displayed.
66 # To put more focus on warnings, be less verbose as default
67 # Use 'make V=1' to see the full commands
69 ifeq ("$(origin V)", "command line")
76 ifeq ($(KBUILD_VERBOSE
),1)
84 # If the user is running make -s (silent mode), suppress echoing of
87 ifneq ($(filter 4.
%,$(MAKE_VERSION
)),) # make-4
88 ifneq ($(filter %s
,$(firstword x
$(MAKEFLAGS
))),)
93 ifneq ($(filter s
% -s
%,$(MAKEFLAGS
)),)
99 export quiet Q KBUILD_VERBOSE
101 # kbuild supports saving output files in a separate directory.
102 # To locate output files in a separate directory two syntaxes are supported.
103 # In both cases the working directory must be the root of the kernel src.
105 # Use "make O=dir/to/store/output/files/"
107 # 2) Set KBUILD_OUTPUT
108 # Set the environment variable KBUILD_OUTPUT to point to the directory
109 # where the output files shall be placed.
110 # export KBUILD_OUTPUT=dir/to/store/output/files/
113 # The O= assignment takes precedence over the KBUILD_OUTPUT environment
116 # KBUILD_SRC is set on invocation of make in OBJ directory
117 # KBUILD_SRC is not intended to be used by the regular user (for now)
118 ifeq ($(KBUILD_SRC
),)
120 # OK, Make called in directory where kernel src resides
121 # Do we want to locate output files in a separate directory?
122 ifeq ("$(origin O)", "command line")
123 KBUILD_OUTPUT
:= $(O
)
126 # That's our default target when none is given on the command line
130 # Cancel implicit rules on top Makefile
131 $(CURDIR
)/Makefile Makefile
: ;
133 ifneq ($(words $(subst :, ,$(CURDIR
))), 1)
134 $(error main directory cannot contain spaces nor colons
)
137 ifneq ($(KBUILD_OUTPUT
),)
138 # Invoke a second make in the output directory, passing relevant variables
139 # check that the output directory actually exists
140 saved-output
:= $(KBUILD_OUTPUT
)
141 KBUILD_OUTPUT
:= $(shell mkdir
-p
$(KBUILD_OUTPUT
) && cd
$(KBUILD_OUTPUT
) \
143 $(if
$(KBUILD_OUTPUT
),, \
144 $(error failed to create output directory
"$(saved-output)"))
146 PHONY
+= $(MAKECMDGOALS
) sub-make
148 $(filter-out _all sub-make
$(CURDIR
)/Makefile
, $(MAKECMDGOALS
)) _all
: sub-make
152 $(Q
)$(MAKE
) -C
$(KBUILD_OUTPUT
) KBUILD_SRC
=$(CURDIR
) \
153 -f
$(CURDIR
)/Makefile
$(filter-out _all sub-make
,$(MAKECMDGOALS
))
155 # Leave processing to above invocation of make
157 endif # ifneq ($(KBUILD_OUTPUT),)
158 endif # ifeq ($(KBUILD_SRC),)
160 # We process the rest of the Makefile if this is the final invocation of make
161 ifeq ($(skip-makefile
),)
163 # Do not print "Entering directory ...",
164 # but we want to display it when entering to the output directory
165 # so that IDEs/editors are able to understand relative filenames.
166 MAKEFLAGS
+= --no-print-directory
168 # Call a source code checker (by default, "sparse") as part of the
171 # Use 'make C=1' to enable checking of only re-compiled files.
172 # Use 'make C=2' to enable checking of *all* source files, regardless
173 # of whether they are re-compiled or not.
175 # See the file "Documentation/dev-tools/sparse.rst" for more details,
176 # including where to get the "sparse" utility.
178 ifeq ("$(origin C)", "command line")
179 KBUILD_CHECKSRC
= $(C
)
181 ifndef KBUILD_CHECKSRC
185 # Use make M=dir to specify directory of external module to build
186 # Old syntax make ... SUBDIRS=$PWD is still supported
187 # Setting the environment variable KBUILD_EXTMOD take precedence
189 KBUILD_EXTMOD ?
= $(SUBDIRS
)
192 ifeq ("$(origin M)", "command line")
193 KBUILD_EXTMOD
:= $(M
)
196 # If building an external module we do not care about the all: rule
197 # but instead _all depend on modules
199 ifeq ($(KBUILD_EXTMOD
),)
205 ifeq ($(KBUILD_SRC
),)
206 # building in the source tree
209 ifeq ($(KBUILD_SRC
)/,$(dir $(CURDIR
)))
210 # building in a subdirectory of the source tree
213 srctree
:= $(KBUILD_SRC
)
220 VPATH
:= $(srctree
)$(if
$(KBUILD_EXTMOD
),:$(KBUILD_EXTMOD
))
222 export srctree objtree VPATH
224 # SUBARCH tells the usermode build what the underlying arch is. That is set
225 # first, and if a usermode build is happening, the "ARCH=um" on the command
226 # line overrides the setting of ARCH below. If a native build is happening,
227 # then ARCH is assigned, getting whatever value it gets normally, and
228 # SUBARCH is subsequently ignored.
230 SUBARCH
:= $(shell uname
-m | sed
-e s
/i
.86/x86
/ -e s
/x86_64
/x86
/ \
231 -e s
/sun4u
/sparc64
/ \
232 -e s
/arm.
*/arm
/ -e s
/sa110
/arm
/ \
233 -e s
/s390x
/s390
/ -e s
/parisc64
/parisc
/ \
234 -e s
/ppc.
*/powerpc
/ -e s
/mips.
*/mips
/ \
235 -e s
/sh
[234].
*/sh
/ -e s
/aarch64.
*/arm64
/ )
237 # Cross compiling and selecting different set of gcc/bin-utils
238 # ---------------------------------------------------------------------------
240 # When performing cross compilation for other architectures ARCH shall be set
241 # to the target architecture. (See arch/* for the possibilities).
242 # ARCH can be set during invocation of make:
244 # Another way is to have ARCH set in the environment.
245 # The default ARCH is the host where make is executed.
247 # CROSS_COMPILE specify the prefix used for all executables used
248 # during compilation. Only gcc and related bin-utils executables
249 # are prefixed with $(CROSS_COMPILE).
250 # CROSS_COMPILE can be set on the command line
251 # make CROSS_COMPILE=ia64-linux-
252 # Alternatively CROSS_COMPILE can be set in the environment.
253 # A third alternative is to store a setting in .config so that plain
254 # "make" in the configured kernel build directory always uses that.
255 # Default value for CROSS_COMPILE is not to prefix executables
256 # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
258 CROSS_COMPILE ?
= $(CONFIG_CROSS_COMPILE
:"%"=%)
260 # Architecture as present in compile.h
261 UTS_MACHINE
:= $(ARCH
)
264 # Additional ARCH settings for x86
268 ifeq ($(ARCH
),x86_64
)
272 # Additional ARCH settings for sparc
273 ifeq ($(ARCH
),sparc32
)
276 ifeq ($(ARCH
),sparc64
)
280 # Additional ARCH settings for sh
285 # Additional ARCH settings for tile
286 ifeq ($(ARCH
),tilepro
)
289 ifeq ($(ARCH
),tilegx
)
293 # Where to locate arch specific headers
294 hdr-arch
:= $(SRCARCH
)
296 KCONFIG_CONFIG ?
= .config
297 export KCONFIG_CONFIG
299 # SHELL used by kbuild
300 CONFIG_SHELL
:= $(shell if
[ -x
"$$BASH" ]; then echo
$$BASH; \
301 else if
[ -x
/bin
/bash
]; then echo
/bin
/bash
; \
302 else echo sh
; fi
; fi
)
306 HOSTCFLAGS
= -Wall
-Wmissing-prototypes
-Wstrict-prototypes
-O2
-fomit-frame-pointer
-std
=gnu89
309 ifeq ($(shell $(HOSTCC
) -v
2>&1 | grep
-c
"clang version"), 1)
310 HOSTCFLAGS
+= -Wno-unused-value
-Wno-unused-parameter \
311 -Wno-missing-field-initializers
-fno-delete-null-pointer-checks
314 # Decide whether to build built-in, modular, or both.
315 # Normally, just do built-in.
320 # If we have only "make modules", don't compile built-in objects.
321 # When we're building modules with modversions, we need to consider
322 # the built-in objects during the descend as well, in order to
323 # make sure the checksums are up to date before we record them.
325 ifeq ($(MAKECMDGOALS
),modules
)
326 KBUILD_BUILTIN
:= $(if
$(CONFIG_MODVERSIONS
),1)
329 # If we have "make <whatever> modules", compile modules
330 # in addition to whatever we do anyway.
331 # Just "make" or "make all" shall build modules as well
333 ifneq ($(filter all _all modules
,$(MAKECMDGOALS
)),)
337 ifeq ($(MAKECMDGOALS
),)
341 export KBUILD_MODULES KBUILD_BUILTIN
342 export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD
344 # We need some generic definitions (do not try to remake the file).
345 scripts
/Kbuild.
include: ;
346 include scripts
/Kbuild.
include
348 # Make variables (CC, etc...)
349 AS
= $(CROSS_COMPILE
)as
350 LD
= $(CROSS_COMPILE
)ld
351 CC
= $(CROSS_COMPILE
)gcc
353 AR
= $(CROSS_COMPILE
)ar
354 NM
= $(CROSS_COMPILE
)nm
355 STRIP
= $(CROSS_COMPILE
)strip
356 OBJCOPY
= $(CROSS_COMPILE
)objcopy
357 OBJDUMP
= $(CROSS_COMPILE
)objdump
359 GENKSYMS
= scripts
/genksyms
/genksyms
360 INSTALLKERNEL
:= installkernel
361 DEPMOD
= /sbin
/depmod
366 CHECKFLAGS
:= -D__linux__
-Dlinux
-D__STDC__
-Dunix
-D__unix__ \
367 -Wbitwise
-Wno-return-void
$(CF
)
375 CFLAGS_GCOV
:= -fprofile-arcs
-ftest-coverage
-fno-tree-loop-im
$(call cc-disable-warning
,maybe-uninitialized
,)
376 CFLAGS_KCOV
:= $(call cc-option
,-fsanitize-coverage
=trace-pc
,)
379 # Use USERINCLUDE when you must reference the UAPI directories only.
381 -I
$(srctree
)/arch
/$(hdr-arch
)/include/uapi \
382 -I
$(objtree
)/arch
/$(hdr-arch
)/include/generated
/uapi \
383 -I
$(srctree
)/include/uapi \
384 -I
$(objtree
)/include/generated
/uapi \
385 -include $(srctree
)/include/linux
/kconfig.h
387 # Use LINUXINCLUDE when you must reference the include/ directory.
388 # Needed to be compatible with the O= option
390 -I
$(srctree
)/arch
/$(hdr-arch
)/include \
391 -I
$(objtree
)/arch
/$(hdr-arch
)/include/generated
/uapi \
392 -I
$(objtree
)/arch
/$(hdr-arch
)/include/generated \
393 $(if
$(KBUILD_SRC
), -I
$(srctree
)/include) \
396 LINUXINCLUDE
+= $(filter-out $(LINUXINCLUDE
),$(USERINCLUDE
))
398 KBUILD_CPPFLAGS
:= -D__KERNEL__
400 KBUILD_CFLAGS
:= -Wall
-Wundef
-Wstrict-prototypes
-Wno-trigraphs \
401 -fno-strict-aliasing
-fno-common \
402 -Werror-implicit-function-declaration \
403 -Wno-format-security \
404 -std
=gnu89
$(call cc-option
,-fno-PIE
)
407 KBUILD_AFLAGS_KERNEL
:=
408 KBUILD_CFLAGS_KERNEL
:=
409 KBUILD_AFLAGS
:= -D__ASSEMBLY__
$(call cc-option
,-fno-PIE
)
410 KBUILD_AFLAGS_MODULE
:= -DMODULE
411 KBUILD_CFLAGS_MODULE
:= -DMODULE
412 KBUILD_LDFLAGS_MODULE
:= -T
$(srctree
)/scripts
/module-common.lds
414 # Read KERNELRELEASE from include/config/kernel.release (if it exists)
415 KERNELRELEASE
= $(shell cat
include/config
/kernel.release
2> /dev
/null
)
416 KERNELVERSION
= $(VERSION
)$(if
$(PATCHLEVEL
),.
$(PATCHLEVEL
)$(if
$(SUBLEVEL
),.
$(SUBLEVEL
)))$(EXTRAVERSION
)
418 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
419 export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
420 export CPP AR NM STRIP OBJCOPY OBJDUMP
421 export MAKE AWK GENKSYMS INSTALLKERNEL PERL PYTHON UTS_MACHINE
422 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
424 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
425 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV CFLAGS_KCOV CFLAGS_KASAN CFLAGS_UBSAN
426 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
427 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
428 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
429 export KBUILD_ARFLAGS
431 # When compiling out-of-tree modules, put MODVERDIR in the module
432 # tree rather than in the kernel tree. The kernel tree might
434 export MODVERDIR
:= $(if
$(KBUILD_EXTMOD
),$(firstword $(KBUILD_EXTMOD
))/).tmp_versions
436 # Files to ignore in find ... statements
438 export RCS_FIND_IGNORE
:= \
( -name SCCS
-o
-name BitKeeper
-o
-name .svn
-o \
439 -name CVS
-o
-name .
pc -o
-name .hg
-o
-name .git \
) \
441 export RCS_TAR_IGNORE
:= --exclude SCCS
--exclude BitKeeper
--exclude .svn \
442 --exclude CVS
--exclude .
pc --exclude .hg
--exclude .git
444 # ===========================================================================
445 # Rules shared between *config targets and build targets
447 # Basic helpers built in scripts/
448 PHONY
+= scripts_basic
450 $(Q
)$(MAKE
) $(build
)=scripts
/basic
451 $(Q
)rm -f .tmp_quiet_recordmcount
453 # To avoid any implicit rule to kick in, define an empty command.
454 scripts
/basic
/%: scripts_basic
;
456 PHONY
+= outputmakefile
457 # outputmakefile generates a Makefile in the output directory, if using a
458 # separate output directory. This allows convenient use of make in the
461 ifneq ($(KBUILD_SRC
),)
462 $(Q
)ln
-fsn
$(srctree
) source
463 $(Q
)$(CONFIG_SHELL
) $(srctree
)/scripts
/mkmakefile \
464 $(srctree
) $(objtree
) $(VERSION
) $(PATCHLEVEL
)
467 # Support for using generic headers in asm-generic
470 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.asm-generic \
471 src
=asm obj
=arch
/$(SRCARCH
)/include/generated
/asm
472 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.asm-generic \
473 src
=uapi
/asm obj
=arch
/$(SRCARCH
)/include/generated
/uapi
/asm
475 # To make sure we do not include .config for any of the *config targets
476 # catch them early, and hand them over to scripts/kconfig/Makefile
477 # It is allowed to specify more targets when calling make, including
478 # mixing *config targets and build targets.
479 # For example 'make oldconfig all'.
480 # Detect when mixed targets is specified, and make a second invocation
481 # of make so .config is not included in this case either (for *config).
483 version_h
:= include/generated
/uapi
/linux
/version.h
484 old_version_h
:= include/linux
/version.h
486 no-dot-config-targets
:= clean mrproper
distclean \
487 cscope gtags TAGS
tags help
% %docs
check% coccicheck \
488 $(version_h
) headers_
% archheaders archscripts \
489 kernelversion
%src-pkg
495 ifneq ($(filter $(no-dot-config-targets
), $(MAKECMDGOALS
)),)
496 ifeq ($(filter-out $(no-dot-config-targets
), $(MAKECMDGOALS
)),)
501 ifeq ($(KBUILD_EXTMOD
),)
502 ifneq ($(filter config
%config
,$(MAKECMDGOALS
)),)
504 ifneq ($(words $(MAKECMDGOALS
)),1)
509 # install and module_install need also be processed one by one
510 ifneq ($(filter install,$(MAKECMDGOALS
)),)
511 ifneq ($(filter modules_install
,$(MAKECMDGOALS
)),)
516 ifeq ($(mixed-targets
),1)
517 # ===========================================================================
518 # We're called with mixed targets (*config and build targets).
519 # Handle them one by one.
521 PHONY
+= $(MAKECMDGOALS
) __build_one_by_one
523 $(filter-out __build_one_by_one
, $(MAKECMDGOALS
)): __build_one_by_one
528 for i in
$(MAKECMDGOALS
); do \
529 $(MAKE
) -f
$(srctree
)/Makefile
$$i; \
533 ifeq ($(config-targets
),1)
534 # ===========================================================================
535 # *config targets only - make sure prerequisites are updated, and descend
536 # in scripts/kconfig to make the *config target
538 # Read arch specific Makefile to set KBUILD_DEFCONFIG as needed.
539 # KBUILD_DEFCONFIG may point out an alternative default configuration
540 # used for 'make defconfig'
541 include arch
/$(SRCARCH
)/Makefile
542 export KBUILD_DEFCONFIG KBUILD_KCONFIG
544 config
: scripts_basic outputmakefile FORCE
545 $(Q
)$(MAKE
) $(build
)=scripts
/kconfig
$@
547 %config
: scripts_basic outputmakefile FORCE
548 $(Q
)$(MAKE
) $(build
)=scripts
/kconfig
$@
551 # ===========================================================================
552 # Build targets only - this includes vmlinux, arch specific targets, clean
553 # targets and others. In general all targets except *config targets.
555 ifeq ($(KBUILD_EXTMOD
),)
556 # Additional helpers built in scripts/
557 # Carefully list dependencies so we do not try to build scripts twice
560 scripts
: scripts_basic
include/config
/auto.conf
include/config
/tristate.conf \
561 asm-generic gcc-plugins
562 $(Q
)$(MAKE
) $(build
)=$(@
)
564 # Objects we will link into vmlinux / subdirs we need to visit
566 drivers-y
:= drivers
/ sound
/ firmware
/
571 endif # KBUILD_EXTMOD
573 ifeq ($(dot-config
),1)
575 -include include/config
/auto.conf
577 ifeq ($(KBUILD_EXTMOD
),)
578 # Read in dependencies to all Kconfig* files, make sure to run
579 # oldconfig if changes are detected.
580 -include include/config
/auto.conf.cmd
582 # To avoid any implicit rule to kick in, define an empty command
583 $(KCONFIG_CONFIG
) include/config
/auto.conf.cmd
: ;
585 # If .config is newer than include/config/auto.conf, someone tinkered
586 # with it and forgot to run make oldconfig.
587 # if auto.conf.cmd is missing then we are probably in a cleaned tree so
588 # we execute the config step to be sure to catch updated Kconfig files
589 include/config
/%.conf
: $(KCONFIG_CONFIG
) include/config
/auto.conf.cmd
590 $(Q
)$(MAKE
) -f
$(srctree
)/Makefile silentoldconfig
592 # external modules needs include/generated/autoconf.h and include/config/auto.conf
593 # but do not care if they are up-to-date. Use auto.conf to trigger the test
594 PHONY
+= include/config
/auto.conf
596 include/config
/auto.conf
:
597 $(Q
)test -e
include/generated
/autoconf.h
-a
-e
$@ ||
( \
599 echo
>&2 " ERROR: Kernel configuration is invalid."; \
600 echo
>&2 " include/generated/autoconf.h or $@ are missing.";\
601 echo
>&2 " Run 'make oldconfig && make prepare' on kernel src to fix it."; \
605 endif # KBUILD_EXTMOD
608 # Dummy target needed, because used as prerequisite
609 include/config
/auto.conf
: ;
610 endif # $(dot-config)
612 # For the kernel to actually contain only the needed exported symbols,
613 # we have to build modules as well to determine what those symbols are.
614 # (this can be evaluated only once include/config/auto.conf has been included)
615 ifdef CONFIG_TRIM_UNUSED_KSYMS
619 # The all: target is the default when no target is given on the
621 # This allow a user to issue only 'make' to build a kernel including modules
622 # Defaults to vmlinux, but the arch makefile usually adds further targets
625 # The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
626 # values of the respective KBUILD_* variables
630 include arch
/$(SRCARCH
)/Makefile
632 KBUILD_CFLAGS
+= $(call cc-option
,-fno-delete-null-pointer-checks
,)
633 KBUILD_CFLAGS
+= $(call cc-disable-warning
,frame-address
,)
635 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
636 KBUILD_CFLAGS
+= $(call cc-option
,-ffunction-sections
,)
637 KBUILD_CFLAGS
+= $(call cc-option
,-fdata-sections
,)
640 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
641 KBUILD_CFLAGS
+= -Os
$(call cc-disable-warning
,maybe-uninitialized
,)
643 ifdef CONFIG_PROFILE_ALL_BRANCHES
644 KBUILD_CFLAGS
+= -O2
$(call cc-disable-warning
,maybe-uninitialized
,)
650 KBUILD_CFLAGS
+= $(call cc-ifversion
, -lt
, 0409, \
651 $(call cc-disable-warning
,maybe-uninitialized
,))
653 # Tell gcc to never replace conditional load with a non-conditional one
654 KBUILD_CFLAGS
+= $(call cc-option
,--param
=allow-store-data-races
=0)
656 # check for 'asm goto'
657 ifeq ($(shell $(CONFIG_SHELL
) $(srctree
)/scripts
/gcc-goto.sh
$(CC
) $(KBUILD_CFLAGS
)), y
)
658 KBUILD_CFLAGS
+= -DCC_HAVE_ASM_GOTO
659 KBUILD_AFLAGS
+= -DCC_HAVE_ASM_GOTO
662 include scripts
/Makefile.gcc-plugins
664 ifdef CONFIG_READABLE_ASM
665 # Disable optimizations that make assembler listings hard to read.
666 # reorder blocks reorders the control in the function
667 # ipa clone creates specialized cloned functions
668 # partial inlining inlines only parts of functions
669 KBUILD_CFLAGS
+= $(call cc-option
,-fno-reorder-blocks
,) \
670 $(call cc-option
,-fno-ipa-cp-clone
,) \
671 $(call cc-option
,-fno-partial-inlining
)
674 ifneq ($(CONFIG_FRAME_WARN
),0)
675 KBUILD_CFLAGS
+= $(call cc-option
,-Wframe-larger-than
=${CONFIG_FRAME_WARN})
678 # This selects the stack protector compiler flag. Testing it is delayed
679 # until after .config has been reprocessed, in the prepare-compiler-check
681 ifdef CONFIG_CC_STACKPROTECTOR_REGULAR
682 stackp-flag
:= -fstack-protector
683 stackp-name
:= REGULAR
685 ifdef CONFIG_CC_STACKPROTECTOR_STRONG
686 stackp-flag
:= -fstack-protector-strong
687 stackp-name
:= STRONG
689 # Force off for distro compilers that enable stack protector by default.
690 stackp-flag
:= $(call cc-option
, -fno-stack-protector
)
693 # Find arch-specific stack protector compiler sanity-checking script.
694 ifdef CONFIG_CC_STACKPROTECTOR
695 stackp-path
:= $(srctree
)/scripts
/gcc-
$(SRCARCH
)_
$(BITS
)-has-stack-protector.sh
696 stackp-check
:= $(wildcard $(stackp-path
))
698 KBUILD_CFLAGS
+= $(stackp-flag
)
700 ifeq ($(cc-name
),clang
)
701 KBUILD_CPPFLAGS
+= $(call cc-option
,-Qunused-arguments
,)
702 KBUILD_CPPFLAGS
+= $(call cc-option
,-Wno-unknown-warning-option
,)
703 KBUILD_CFLAGS
+= $(call cc-disable-warning
, unused-variable
)
704 KBUILD_CFLAGS
+= $(call cc-disable-warning
, format-invalid-specifier
)
705 KBUILD_CFLAGS
+= $(call cc-disable-warning
, gnu
)
706 # Quiet clang warning: comparison of unsigned expression < 0 is always false
707 KBUILD_CFLAGS
+= $(call cc-disable-warning
, tautological-compare
)
708 # CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
709 # source of a reference will be _MergedGlobals and not on of the whitelisted names.
710 # See modpost pattern 2
711 KBUILD_CFLAGS
+= $(call cc-option
, -mno-global-merge
,)
712 KBUILD_CFLAGS
+= $(call cc-option
, -fcatch-undefined-behavior
)
715 # These warnings generated too much noise in a regular build.
716 # Use make W=1 to enable them (see scripts/Makefile.build)
717 KBUILD_CFLAGS
+= $(call cc-disable-warning
, unused-but-set-variable
)
718 KBUILD_CFLAGS
+= $(call cc-disable-warning
, unused-const-variable
)
721 ifdef CONFIG_FRAME_POINTER
722 KBUILD_CFLAGS
+= -fno-omit-frame-pointer
-fno-optimize-sibling-calls
724 # Some targets (ARM with Thumb2, for example), can't be built with frame
725 # pointers. For those, we don't have FUNCTION_TRACER automatically
726 # select FRAME_POINTER. However, FUNCTION_TRACER adds -pg, and this is
727 # incompatible with -fomit-frame-pointer with current GCC, so we don't use
728 # -fomit-frame-pointer with FUNCTION_TRACER.
729 ifndef CONFIG_FUNCTION_TRACER
730 KBUILD_CFLAGS
+= -fomit-frame-pointer
734 KBUILD_CFLAGS
+= $(call cc-option
, -fno-var-tracking-assignments
)
736 ifdef CONFIG_DEBUG_INFO
737 ifdef CONFIG_DEBUG_INFO_SPLIT
738 KBUILD_CFLAGS
+= $(call cc-option
, -gsplit-dwarf
, -g
)
742 KBUILD_AFLAGS
+= -Wa
,-gdwarf-2
744 ifdef CONFIG_DEBUG_INFO_DWARF4
745 KBUILD_CFLAGS
+= $(call cc-option
, -gdwarf-4
,)
748 ifdef CONFIG_DEBUG_INFO_REDUCED
749 KBUILD_CFLAGS
+= $(call cc-option
, -femit-struct-debug-baseonly
) \
750 $(call cc-option
,-fno-var-tracking
)
753 ifdef CONFIG_FUNCTION_TRACER
754 ifndef CC_FLAGS_FTRACE
755 CC_FLAGS_FTRACE
:= -pg
757 export CC_FLAGS_FTRACE
758 ifdef CONFIG_HAVE_FENTRY
759 CC_USING_FENTRY
:= $(call cc-option
, -mfentry
-DCC_USING_FENTRY
)
761 KBUILD_CFLAGS
+= $(CC_FLAGS_FTRACE
) $(CC_USING_FENTRY
)
762 KBUILD_AFLAGS
+= $(CC_USING_FENTRY
)
763 ifdef CONFIG_DYNAMIC_FTRACE
764 ifdef CONFIG_HAVE_C_RECORDMCOUNT
765 BUILD_C_RECORDMCOUNT
:= y
766 export BUILD_C_RECORDMCOUNT
771 # We trigger additional mismatches with less inlining
772 ifdef CONFIG_DEBUG_SECTION_MISMATCH
773 KBUILD_CFLAGS
+= $(call cc-option
, -fno-inline-functions-called-once
)
776 # arch Makefile may override CC so keep this after arch Makefile is included
777 NOSTDINC_FLAGS
+= -nostdinc
-isystem
$(shell $(CC
) -print-file-name
=include)
778 CHECKFLAGS
+= $(NOSTDINC_FLAGS
)
780 # warn about C99 declaration after statement
781 KBUILD_CFLAGS
+= $(call cc-option
,-Wdeclaration-after-statement
,)
783 # disable pointer signed / unsigned warnings in gcc 4.0
784 KBUILD_CFLAGS
+= $(call cc-disable-warning
, pointer-sign
)
786 # disable invalid "can't wrap" optimizations for signed / pointers
787 KBUILD_CFLAGS
+= $(call cc-option
,-fno-strict-overflow
)
789 # conserve stack if available
790 KBUILD_CFLAGS
+= $(call cc-option
,-fconserve-stack
)
792 # disallow errors like 'EXPORT_GPL(foo);' with missing header
793 KBUILD_CFLAGS
+= $(call cc-option
,-Werror
=implicit-int
)
795 # require functions to have arguments in prototypes, not empty 'int foo()'
796 KBUILD_CFLAGS
+= $(call cc-option
,-Werror
=strict-prototypes
)
798 # Prohibit date/time macros, which would make the build non-deterministic
799 KBUILD_CFLAGS
+= $(call cc-option
,-Werror
=date-time
)
801 # enforce correct pointer usage
802 KBUILD_CFLAGS
+= $(call cc-option
,-Werror
=incompatible-pointer-types
)
804 # use the deterministic mode of AR if available
805 KBUILD_ARFLAGS
:= $(call ar-option
,D
)
807 include scripts
/Makefile.kasan
808 include scripts
/Makefile.extrawarn
809 include scripts
/Makefile.ubsan
811 # Add any arch overrides and user supplied CPPFLAGS, AFLAGS and CFLAGS as the
813 KBUILD_CPPFLAGS
+= $(ARCH_CPPFLAGS
) $(KCPPFLAGS
)
814 KBUILD_AFLAGS
+= $(ARCH_AFLAGS
) $(KAFLAGS
)
815 KBUILD_CFLAGS
+= $(ARCH_CFLAGS
) $(KCFLAGS
)
817 # Use --build-id when available.
818 LDFLAGS_BUILD_ID
= $(patsubst -Wl
$(comma
)%,%,\
819 $(call cc-ldoption
, -Wl
$(comma
)--build-id
,))
820 KBUILD_LDFLAGS_MODULE
+= $(LDFLAGS_BUILD_ID
)
821 LDFLAGS_vmlinux
+= $(LDFLAGS_BUILD_ID
)
823 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
824 LDFLAGS_vmlinux
+= $(call ld-option
, --gc-sections
,)
827 ifeq ($(CONFIG_STRIP_ASM_SYMS
),y
)
828 LDFLAGS_vmlinux
+= $(call ld-option
, -X
,)
831 # Default kernel image to build when no specific target is given.
832 # KBUILD_IMAGE may be overruled on the command line or
833 # set in the environment
834 # Also any assignments in arch/$(ARCH)/Makefile take precedence over
836 export KBUILD_IMAGE ?
= vmlinux
839 # INSTALL_PATH specifies where to place the updated kernel and system map
840 # images. Default is /boot, but you can set it to other values
841 export INSTALL_PATH ?
= /boot
844 # INSTALL_DTBS_PATH specifies a prefix for relocations required by build roots.
845 # Like INSTALL_MOD_PATH, it isn't defined in the Makefile, but can be passed as
846 # an argument if needed. Otherwise it defaults to the kernel install path
848 export INSTALL_DTBS_PATH ?
= $(INSTALL_PATH
)/dtbs
/$(KERNELRELEASE
)
851 # INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
852 # relocations required by build roots. This is not defined in the
853 # makefile but the argument can be passed to make if needed.
856 MODLIB
= $(INSTALL_MOD_PATH
)/lib
/modules
/$(KERNELRELEASE
)
860 # INSTALL_MOD_STRIP, if defined, will cause modules to be
861 # stripped after they are installed. If INSTALL_MOD_STRIP is '1', then
862 # the default option --strip-debug will be used. Otherwise,
863 # INSTALL_MOD_STRIP value will be used as the options to the strip command.
865 ifdef INSTALL_MOD_STRIP
866 ifeq ($(INSTALL_MOD_STRIP
),1)
867 mod_strip_cmd
= $(STRIP
) --strip-debug
869 mod_strip_cmd
= $(STRIP
) $(INSTALL_MOD_STRIP
)
870 endif # INSTALL_MOD_STRIP=1
873 endif # INSTALL_MOD_STRIP
876 # CONFIG_MODULE_COMPRESS, if defined, will cause module to be compressed
877 # after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP
878 # or CONFIG_MODULE_COMPRESS_XZ.
880 mod_compress_cmd
= true
881 ifdef CONFIG_MODULE_COMPRESS
882 ifdef CONFIG_MODULE_COMPRESS_GZIP
883 mod_compress_cmd
= gzip
-n
-f
884 endif # CONFIG_MODULE_COMPRESS_GZIP
885 ifdef CONFIG_MODULE_COMPRESS_XZ
886 mod_compress_cmd
= xz
-f
887 endif # CONFIG_MODULE_COMPRESS_XZ
888 endif # CONFIG_MODULE_COMPRESS
889 export mod_compress_cmd
891 # Select initial ramdisk compression format, default is gzip(1).
892 # This shall be used by the dracut(8) tool while creating an initramfs image.
894 INITRD_COMPRESS-y
:= gzip
895 INITRD_COMPRESS-
$(CONFIG_RD_BZIP2
) := bzip2
896 INITRD_COMPRESS-
$(CONFIG_RD_LZMA
) := lzma
897 INITRD_COMPRESS-
$(CONFIG_RD_XZ
) := xz
898 INITRD_COMPRESS-
$(CONFIG_RD_LZO
) := lzo
899 INITRD_COMPRESS-
$(CONFIG_RD_LZ4
) := lz4
900 # do not export INITRD_COMPRESS, since we didn't actually
901 # choose a sane default compression above.
902 # export INITRD_COMPRESS := $(INITRD_COMPRESS-y)
904 ifdef CONFIG_MODULE_SIG_ALL
905 $(eval
$(call config_filename
,MODULE_SIG_KEY
))
907 mod_sign_cmd
= scripts
/sign-file
$(CONFIG_MODULE_SIG_HASH
) $(MODULE_SIG_KEY_SRCPREFIX
)$(CONFIG_MODULE_SIG_KEY
) certs
/signing_key.x509
913 ifdef CONFIG_STACK_VALIDATION
914 has_libelf
:= $(call try-run
,\
915 echo
"int main() {}" |
$(HOSTCC
) -xc
-o
/dev
/null
-lelf
-,1,0)
916 ifeq ($(has_libelf
),1)
917 objtool_target
:= tools
/objtool FORCE
919 $(warning
"Cannot use CONFIG_STACK_VALIDATION, please install libelf-dev, libelf-devel or elfutils-libelf-devel")
920 SKIP_STACK_VALIDATION
:= 1
921 export SKIP_STACK_VALIDATION
926 ifeq ($(KBUILD_EXTMOD
),)
927 core-y
+= kernel
/ certs
/ mm
/ fs
/ ipc
/ security
/ crypto
/ block
/
929 vmlinux-dirs
:= $(patsubst %/,%,$(filter %/, $(init-y
) $(init-m
) \
930 $(core-y
) $(core-m
) $(drivers-y
) $(drivers-m
) \
931 $(net-y
) $(net-m
) $(libs-y
) $(libs-m
) $(virt-y
)))
933 vmlinux-alldirs
:= $(sort $(vmlinux-dirs
) $(patsubst %/,%,$(filter %/, \
934 $(init-
) $(core-
) $(drivers-
) $(net-
) $(libs-
) $(virt-
))))
936 init-y
:= $(patsubst %/, %/built-in.o
, $(init-y
))
937 core-y
:= $(patsubst %/, %/built-in.o
, $(core-y
))
938 drivers-y
:= $(patsubst %/, %/built-in.o
, $(drivers-y
))
939 net-y
:= $(patsubst %/, %/built-in.o
, $(net-y
))
940 libs-y1
:= $(patsubst %/, %/lib.a
, $(libs-y
))
941 libs-y2
:= $(patsubst %/, %/built-in.o
, $(libs-y
))
942 libs-y
:= $(libs-y1
) $(libs-y2
)
943 virt-y
:= $(patsubst %/, %/built-in.o
, $(virt-y
))
945 # Externally visible symbols (used by link-vmlinux.sh)
946 export KBUILD_VMLINUX_INIT
:= $(head-y
) $(init-y
)
947 export KBUILD_VMLINUX_MAIN
:= $(core-y
) $(libs-y
) $(drivers-y
) $(net-y
) $(virt-y
)
948 export KBUILD_LDS
:= arch
/$(SRCARCH
)/kernel
/vmlinux.lds
949 export LDFLAGS_vmlinux
950 # used by scripts/pacmage/Makefile
951 export KBUILD_ALLDIRS
:= $(sort $(filter-out arch
/%,$(vmlinux-alldirs
)) arch Documentation
include samples scripts tools
)
953 vmlinux-deps
:= $(KBUILD_LDS
) $(KBUILD_VMLINUX_INIT
) $(KBUILD_VMLINUX_MAIN
)
955 # Include targets which we want to execute sequentially if the rest of the
956 # kernel build went well. If CONFIG_TRIM_UNUSED_KSYMS is set, this might be
957 # evaluated more than once.
958 PHONY
+= vmlinux_prereq
959 vmlinux_prereq
: $(vmlinux-deps
) FORCE
960 ifdef CONFIG_HEADERS_CHECK
961 $(Q
)$(MAKE
) -f
$(srctree
)/Makefile headers_check
963 ifdef CONFIG_GDB_SCRIPTS
964 $(Q
)ln
-fsn
`cd $(srctree) && /bin/pwd`/scripts
/gdb
/vmlinux-gdb.py
966 ifdef CONFIG_TRIM_UNUSED_KSYMS
967 $(Q
)$(CONFIG_SHELL
) $(srctree
)/scripts
/adjust_autoksyms.sh \
968 "$(MAKE) -f $(srctree)/Makefile vmlinux"
971 # standalone target for easier testing
972 include/generated
/autoksyms.h
: FORCE
973 $(Q
)$(CONFIG_SHELL
) $(srctree
)/scripts
/adjust_autoksyms.sh true
975 ARCH_POSTLINK
:= $(wildcard $(srctree
)/arch
/$(SRCARCH
)/Makefile.postlink
)
977 # Final link of vmlinux with optional arch pass after final link
979 $(CONFIG_SHELL
) $< $(LD
) $(LDFLAGS
) $(LDFLAGS_vmlinux
) ; \
980 $(if
$(ARCH_POSTLINK
), $(MAKE
) -f
$(ARCH_POSTLINK
) $@
, true
)
982 vmlinux
: scripts
/link-vmlinux.sh vmlinux_prereq
$(vmlinux-deps
) FORCE
983 +$(call if_changed
,link-vmlinux
)
985 # Build samples along the rest of the kernel
987 vmlinux-dirs
+= samples
990 # The actual objects are generated when descending,
991 # make sure no implicit rule kicks in
992 $(sort $(vmlinux-deps
)): $(vmlinux-dirs
) ;
994 # Handle descending into subdirectories listed in $(vmlinux-dirs)
995 # Preset locale variables to speed up the build process. Limit locale
996 # tweaks to this spot to avoid wrong language settings when running
997 # make menuconfig etc.
998 # Error messages still appears in the original language
1000 PHONY
+= $(vmlinux-dirs
)
1001 $(vmlinux-dirs
): prepare scripts
1002 $(Q
)$(MAKE
) $(build
)=$@
1004 define filechk_kernel.release
1005 echo
"$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
1008 # Store (new) KERNELRELEASE string in include/config/kernel.release
1009 include/config
/kernel.release
: include/config
/auto.conf FORCE
1010 $(call filechk
,kernel.release
)
1013 # Things we need to do before we recursively start building the kernel
1014 # or the modules are listed in "prepare".
1015 # A multi level approach is used. prepareN is processed before prepareN-1.
1016 # archprepare is used in arch Makefiles and when processed asm symlink,
1017 # version.h and scripts_basic is processed / created.
1019 # Listed in dependency order
1020 PHONY
+= prepare archprepare prepare0 prepare1 prepare2 prepare3
1022 # prepare3 is used to check if we are building in a separate output directory,
1024 # 1) Check that make has not been executed in the kernel src $(srctree)
1025 prepare3
: include/config
/kernel.release
1026 ifneq ($(KBUILD_SRC
),)
1027 @
$(kecho
) ' Using $(srctree) as source for kernel'
1028 $(Q
)if
[ -f
$(srctree
)/.config
-o
-d
$(srctree
)/include/config
]; then \
1029 echo
>&2 " $(srctree) is not clean, please run 'make mrproper'"; \
1030 echo
>&2 " in the '$(srctree)' directory.";\
1035 # prepare2 creates a makefile if using a separate output directory.
1036 # From this point forward, .config has been reprocessed, so any rules
1037 # that need to depend on updated CONFIG_* values can be checked here.
1038 prepare2
: prepare3 prepare-compiler-check outputmakefile asm-generic
1040 prepare1
: prepare2
$(version_h
) include/generated
/utsrelease.h \
1041 include/config
/auto.conf
1044 archprepare
: archheaders archscripts prepare1 scripts_basic
1046 prepare0
: archprepare gcc-plugins
1047 $(Q
)$(MAKE
) $(build
)=.
1049 # All the preparing..
1050 prepare
: prepare0 prepare-objtool
1052 PHONY
+= prepare-objtool
1053 prepare-objtool
: $(objtool_target
)
1055 # Check for CONFIG flags that require compiler support. Abort the build
1056 # after .config has been processed, but before the kernel build starts.
1058 # For security-sensitive CONFIG options, we don't want to fallback and/or
1059 # silently change which compiler flags will be used, since that leads to
1060 # producing kernels with different security feature characteristics
1061 # depending on the compiler used. (For example, "But I selected
1062 # CC_STACKPROTECTOR_STRONG! Why did it build with _REGULAR?!")
1063 PHONY
+= prepare-compiler-check
1064 prepare-compiler-check
: FORCE
1065 # Make sure compiler supports requested stack protector flag.
1067 ifeq ($(call cc-option
, $(stackp-flag
)),)
1068 @echo Cannot use CONFIG_CC_STACKPROTECTOR_
$(stackp-name
): \
1069 $(stackp-flag
) not supported by compiler
>&2 && exit
1
1072 # Make sure compiler does not have buggy stack-protector support.
1074 ifneq ($(shell $(CONFIG_SHELL
) $(stackp-check
) $(CC
) $(KBUILD_CPPFLAGS
) $(biarch
)),y
)
1075 @echo Cannot use CONFIG_CC_STACKPROTECTOR_
$(stackp-name
): \
1076 $(stackp-flag
) available but compiler is broken
>&2 && exit
1
1081 # Generate some files
1082 # ---------------------------------------------------------------------------
1084 # KERNELRELEASE can change from a few different places, meaning version.h
1085 # needs to be updated, so this check is forced on all builds
1088 define filechk_utsrelease.h
1089 if
[ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt
$(uts_len
) ]; then \
1090 echo
'"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2; \
1093 (echo \
#define UTS_RELEASE \"$(KERNELRELEASE)\";)
1096 define filechk_version.h
1097 (echo \
#define LINUX_VERSION_CODE $(shell \
1098 expr
$(VERSION
) \
* 65536 + 0$(PATCHLEVEL
) \
* 256 + 0$(SUBLEVEL
)); \
1099 echo
'#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))';)
1102 $(version_h
): $(srctree
)/Makefile FORCE
1103 $(call filechk
,version.h
)
1104 $(Q
)rm -f
$(old_version_h
)
1106 include/generated
/utsrelease.h
: include/config
/kernel.release FORCE
1107 $(call filechk
,utsrelease.h
)
1111 $(Q
)find
$(srctree
)/include/ -name
'*.h' | xargs
--max-args
1 \
1112 $(srctree
)/scripts
/headerdep.pl
-I
$(srctree
)/include
1114 # ---------------------------------------------------------------------------
1116 INSTALL_FW_PATH
=$(INSTALL_MOD_PATH
)/lib
/firmware
1117 export INSTALL_FW_PATH
1119 PHONY
+= firmware_install
1121 @mkdir
-p
$(objtree
)/firmware
1122 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.fwinst obj
=firmware __fw_install
1124 # ---------------------------------------------------------------------------
1127 #Default location for installed headers
1128 export INSTALL_HDR_PATH
= $(objtree
)/usr
1130 # If we do an all arch process set dst to asm-$(hdr-arch)
1131 hdr-dst
= $(if
$(KBUILD_HEADERS
), dst
=include/asm-
$(hdr-arch
), dst
=include/asm
)
1133 PHONY
+= archheaders
1136 PHONY
+= archscripts
1140 __headers
: $(version_h
) scripts_basic asm-generic archheaders archscripts
1141 $(Q
)$(MAKE
) $(build
)=scripts build_unifdef
1143 PHONY
+= headers_install_all
1144 headers_install_all
:
1145 $(Q
)$(CONFIG_SHELL
) $(srctree
)/scripts
/headers.sh
install
1147 PHONY
+= headers_install
1148 headers_install
: __headers
1149 $(if
$(wildcard $(srctree
)/arch
/$(hdr-arch
)/include/uapi
/asm
/Kbuild
),, \
1150 $(error Headers not exportable for the
$(SRCARCH
) architecture
))
1151 $(Q
)$(MAKE
) $(hdr-inst
)=include/uapi
1152 $(Q
)$(MAKE
) $(hdr-inst
)=arch
/$(hdr-arch
)/include/uapi
/asm
$(hdr-dst
)
1154 PHONY
+= headers_check_all
1155 headers_check_all
: headers_install_all
1156 $(Q
)$(CONFIG_SHELL
) $(srctree
)/scripts
/headers.sh
check
1158 PHONY
+= headers_check
1159 headers_check
: headers_install
1160 $(Q
)$(MAKE
) $(hdr-inst
)=include/uapi HDRCHECK
=1
1161 $(Q
)$(MAKE
) $(hdr-inst
)=arch
/$(hdr-arch
)/include/uapi
/asm
$(hdr-dst
) HDRCHECK
=1
1163 # ---------------------------------------------------------------------------
1168 $(Q
)$(MAKE
) -C tools
/testing
/selftests run_tests
1171 $(Q
)$(MAKE
) -C tools
/testing
/selftests
clean
1173 PHONY
+= kselftest-merge
1175 $(if
$(wildcard $(objtree
)/.config
),, $(error No .config exists
, config your kernel first
!))
1176 $(Q
)$(CONFIG_SHELL
) $(srctree
)/scripts
/kconfig
/merge_config.sh \
1177 -m
$(objtree
)/.config \
1178 $(srctree
)/tools
/testing
/selftests
/*/config
1179 +$(Q
)$(MAKE
) -f
$(srctree
)/Makefile olddefconfig
1181 # ---------------------------------------------------------------------------
1184 ifdef CONFIG_MODULES
1186 # By default, build modules as well
1192 # A module can be listed more than once in obj-m resulting in
1193 # duplicate lines in modules.order files. Those are removed
1194 # using awk while concatenating to the final file.
1197 modules
: $(vmlinux-dirs
) $(if
$(KBUILD_BUILTIN
),vmlinux
) modules.builtin
1198 $(Q
)$(AWK
) '!x[$$0]++' $(vmlinux-dirs
:%=$(objtree
)/%/modules.order
) > $(objtree
)/modules.order
1199 @
$(kecho
) ' Building modules, stage 2.';
1200 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.modpost
1201 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.fwinst obj
=firmware __fw_modbuild
1203 modules.builtin
: $(vmlinux-dirs
:%=%/modules.builtin
)
1204 $(Q
)$(AWK
) '!x[$$0]++' $^
> $(objtree
)/modules.builtin
1206 %/modules.builtin
: include/config
/auto.conf
1207 $(Q
)$(MAKE
) $(modbuiltin
)=$*
1210 # Target to prepare building external modules
1211 PHONY
+= modules_prepare
1212 modules_prepare
: prepare scripts
1214 # Target to install modules
1215 PHONY
+= modules_install
1216 modules_install
: _modinst_ _modinst_post
1220 @
rm -rf
$(MODLIB
)/kernel
1221 @
rm -f
$(MODLIB
)/source
1222 @mkdir
-p
$(MODLIB
)/kernel
1223 @ln
-s
`cd $(srctree) && /bin/pwd` $(MODLIB
)/source
1224 @if
[ ! $(objtree
) -ef
$(MODLIB
)/build
]; then \
1225 rm -f
$(MODLIB
)/build
; \
1226 ln
-s
$(CURDIR
) $(MODLIB
)/build
; \
1228 @cp
-f
$(objtree
)/modules.order
$(MODLIB
)/
1229 @cp
-f
$(objtree
)/modules.builtin
$(MODLIB
)/
1230 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.modinst
1232 # This depmod is only for convenience to give the initial
1233 # boot a modules.dep even before / is mounted read-write. However the
1234 # boot script depmod is the master version.
1235 PHONY
+= _modinst_post
1236 _modinst_post
: _modinst_
1237 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.fwinst obj
=firmware __fw_modinst
1240 ifeq ($(CONFIG_MODULE_SIG
), y
)
1241 PHONY
+= modules_sign
1243 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.modsign
1246 else # CONFIG_MODULES
1248 # Modules not configured
1249 # ---------------------------------------------------------------------------
1251 PHONY
+= modules modules_install
1252 modules modules_install
:
1254 @echo
>&2 "The present kernel configuration has modules disabled."
1255 @echo
>&2 "Type 'make config' and enable loadable module support."
1256 @echo
>&2 "Then build a kernel with module support enabled."
1260 endif # CONFIG_MODULES
1263 # Cleaning is done on three levels.
1264 # make clean Delete most generated files
1265 # Leave enough to build external modules
1266 # make mrproper Delete the current configuration, and all generated files
1267 # make distclean Remove editor backup files, patch leftover files and the like
1269 # Directories & files removed with 'make clean'
1270 CLEAN_DIRS
+= $(MODVERDIR
)
1272 # Directories & files removed with 'make mrproper'
1273 MRPROPER_DIRS
+= include/config usr
/include include/generated \
1274 arch
/*/include/generated .tmp_objdiff
1275 MRPROPER_FILES
+= .config .config.old .version .old_version \
1276 Module.symvers
tags TAGS cscope
* GPATH GTAGS GRTAGS GSYMS \
1277 signing_key.pem signing_key.priv signing_key.x509 \
1278 x509.genkey extra_certificates signing_key.x509.keyid \
1279 signing_key.x509.signer vmlinux-gdb.py
1281 # clean - Delete most, but leave enough to build external modules
1283 clean: rm-dirs
:= $(CLEAN_DIRS
)
1284 clean: rm-files
:= $(CLEAN_FILES
)
1285 clean-dirs
:= $(addprefix _clean_
, .
$(vmlinux-alldirs
) Documentation samples
)
1287 PHONY
+= $(clean-dirs
) clean archclean vmlinuxclean
1289 $(Q
)$(MAKE
) $(clean)=$(patsubst _clean_
%,%,$@
)
1292 $(Q
)$(CONFIG_SHELL
) $(srctree
)/scripts
/link-vmlinux.sh
clean
1293 $(Q
)$(if
$(ARCH_POSTLINK
), $(MAKE
) -f
$(ARCH_POSTLINK
) clean)
1295 clean: archclean vmlinuxclean
1297 # mrproper - Delete all generated files, including .config
1299 mrproper
: rm-dirs
:= $(wildcard $(MRPROPER_DIRS
))
1300 mrproper
: rm-files
:= $(wildcard $(MRPROPER_FILES
))
1301 mrproper-dirs
:= $(addprefix _mrproper_
,Documentation
/DocBook scripts
)
1303 PHONY
+= $(mrproper-dirs
) mrproper archmrproper
1305 $(Q
)$(MAKE
) $(clean)=$(patsubst _mrproper_
%,%,$@
)
1307 mrproper
: clean archmrproper
$(mrproper-dirs
)
1316 @find
$(srctree
) $(RCS_FIND_IGNORE
) \
1317 \
( -name
'*.orig' -o
-name
'*.rej' -o
-name
'*~' \
1318 -o
-name
'*.bak' -o
-name
'#*#' -o
-name
'.*.orig' \
1319 -o
-name
'.*.rej' -o
-name
'*%' -o
-name
'core' \
) \
1320 -type f
-print | xargs
rm -f
1323 # Packaging of the kernel to various formats
1324 # ---------------------------------------------------------------------------
1325 # rpm target kept for backward compatibility
1326 package-dir
:= scripts
/package
1329 $(Q
)$(MAKE
) $(build
)=$(package-dir
) $@
1330 %pkg
: include/config
/kernel.release FORCE
1331 $(Q
)$(MAKE
) $(build
)=$(package-dir
) $@
1332 rpm
: include/config
/kernel.release FORCE
1333 $(Q
)$(MAKE
) $(build
)=$(package-dir
) $@
1336 # Brief documentation of the typical targets used
1337 # ---------------------------------------------------------------------------
1339 boards
:= $(wildcard $(srctree
)/arch
/$(SRCARCH
)/configs
/*_defconfig
)
1340 boards
:= $(sort $(notdir $(boards
)))
1341 board-dirs
:= $(dir $(wildcard $(srctree
)/arch
/$(SRCARCH
)/configs
/*/*_defconfig
))
1342 board-dirs
:= $(sort $(notdir $(board-dirs
:/=)))
1346 @echo
'Cleaning targets:'
1347 @echo
' clean - Remove most generated files but keep the config and'
1348 @echo
' enough build support to build external modules'
1349 @echo
' mrproper - Remove all generated files + config + various backup files'
1350 @echo
' distclean - mrproper + remove editor backup and patch files'
1352 @echo
'Configuration targets:'
1353 @
$(MAKE
) -f
$(srctree
)/scripts
/kconfig
/Makefile help
1355 @echo
'Other generic targets:'
1356 @echo
' all - Build all targets marked with [*]'
1357 @echo
'* vmlinux - Build the bare kernel'
1358 @echo
'* modules - Build all modules'
1359 @echo
' modules_install - Install all modules to INSTALL_MOD_PATH (default: /)'
1360 @echo
' firmware_install- Install all firmware to INSTALL_FW_PATH'
1361 @echo
' (default: $$(INSTALL_MOD_PATH)/lib/firmware)'
1362 @echo
' dir/ - Build all files in dir and below'
1363 @echo
' dir/file.[ois] - Build specified target only'
1364 @echo
' dir/file.lst - Build specified mixed source/assembly target only'
1365 @echo
' (requires a recent binutils and recent build (System.map))'
1366 @echo
' dir/file.ko - Build module including final link'
1367 @echo
' modules_prepare - Set up for building external modules'
1368 @echo
' tags/TAGS - Generate tags file for editors'
1369 @echo
' cscope - Generate cscope index'
1370 @echo
' gtags - Generate GNU GLOBAL index'
1371 @echo
' kernelrelease - Output the release version string (use with make -s)'
1372 @echo
' kernelversion - Output the version stored in Makefile (use with make -s)'
1373 @echo
' image_name - Output the image name (use with make -s)'
1374 @echo
' headers_install - Install sanitised kernel headers to INSTALL_HDR_PATH'; \
1375 echo
' (default: $(INSTALL_HDR_PATH))'; \
1377 @echo
'Static analysers'
1378 @echo
' checkstack - Generate a list of stack hogs'
1379 @echo
' namespacecheck - Name space analysis on compiled kernel'
1380 @echo
' versioncheck - Sanity check on version.h usage'
1381 @echo
' includecheck - Check for duplicate included header files'
1382 @echo
' export_report - List the usages of all exported symbols'
1383 @echo
' headers_check - Sanity check on exported headers'
1384 @echo
' headerdep - Detect inclusion cycles in headers'
1385 @
$(MAKE
) -f
$(srctree
)/scripts
/Makefile.help checker-help
1387 @echo
'Kernel selftest'
1388 @echo
' kselftest - Build and run kernel selftest (run as root)'
1389 @echo
' Build, install, and boot kernel before'
1390 @echo
' running kselftest on it'
1391 @echo
' kselftest-clean - Remove all generated kselftest files'
1392 @echo
' kselftest-merge - Merge all the config dependencies of kselftest to existed'
1395 @echo
'Kernel packaging:'
1396 @
$(MAKE
) $(build
)=$(package-dir
) help
1398 @echo
'Documentation targets:'
1399 @
$(MAKE
) -f
$(srctree
)/Documentation
/Makefile.sphinx dochelp
1401 @
$(MAKE
) -f
$(srctree
)/Documentation
/DocBook
/Makefile dochelp
1403 @echo
'Architecture specific targets ($(SRCARCH)):'
1404 @
$(if
$(archhelp
),$(archhelp
),\
1405 echo
' No architecture specific help defined for $(SRCARCH)')
1408 $(foreach b
, $(boards
), \
1409 printf
" %-24s - Build for %s\\n" $(b
) $(subst _defconfig
,,$(b
));) \
1411 @
$(if
$(board-dirs
), \
1412 $(foreach b
, $(board-dirs
), \
1413 printf
" %-16s - Show %s-specific targets\\n" help-
$(b
) $(b
);) \
1414 printf
" %-16s - Show all of the above\\n" help-boards
; \
1417 @echo
' make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
1418 @echo
' make V=2 [targets] 2 => give reason for rebuild of target'
1419 @echo
' make O=dir [targets] Locate all output files in "dir", including .config'
1420 @echo
' make C=1 [targets] Check all c source with $$CHECK (sparse by default)'
1421 @echo
' make C=2 [targets] Force check of all c source with $$CHECK'
1422 @echo
' make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections'
1423 @echo
' make W=n [targets] Enable extra gcc checks, n=1,2,3 where'
1424 @echo
' 1: warnings which may be relevant and do not occur too often'
1425 @echo
' 2: warnings which occur quite often but may still be relevant'
1426 @echo
' 3: more obscure warnings, can most likely be ignored'
1427 @echo
' Multiple levels can be combined with W=12 or W=123'
1429 @echo
'Execute "make" or "make all" to build all targets marked with [*] '
1430 @echo
'For further info see the ./README file'
1433 help-board-dirs
:= $(addprefix help-
,$(board-dirs
))
1435 help-boards
: $(help-board-dirs
)
1437 boards-per-dir
= $(sort $(notdir $(wildcard $(srctree
)/arch
/$(SRCARCH
)/configs
/$*/*_defconfig
)))
1439 $(help-board-dirs
): help-
%:
1440 @echo
'Architecture specific targets ($(SRCARCH) $*):'
1441 @
$(if
$(boards-per-dir
), \
1442 $(foreach b
, $(boards-per-dir
), \
1443 printf
" %-24s - Build for %s\\n" $*/$(b
) $(subst _defconfig
,,$(b
));) \
1447 # Documentation targets
1448 # ---------------------------------------------------------------------------
1449 DOC_TARGETS
:= xmldocs sgmldocs psdocs latexdocs pdfdocs htmldocs mandocs installmandocs epubdocs cleandocs linkcheckdocs
1450 PHONY
+= $(DOC_TARGETS
)
1451 $(DOC_TARGETS
): scripts_basic FORCE
1452 $(Q
)$(MAKE
) $(build
)=scripts build_docproc build_check-lc_ctype
1453 $(Q
)$(MAKE
) $(build
)=Documentation
-f
$(srctree
)/Documentation
/Makefile.sphinx
$@
1454 $(Q
)$(MAKE
) $(build
)=Documentation
/DocBook
$@
1456 else # KBUILD_EXTMOD
1459 # External module support.
1460 # When building external modules the kernel used as basis is considered
1461 # read-only, and no consistency checks are made and the make
1462 # system is not used on the basis kernel. If updates are required
1463 # in the basis kernel ordinary make commands (without M=...) must
1466 # The following are the only valid targets when building external
1468 # make M=dir clean Delete all automatically generated files
1469 # make M=dir modules Make all modules in specified dir
1470 # make M=dir Same as 'make M=dir modules'
1471 # make M=dir modules_install
1472 # Install the modules built in the module directory
1473 # Assumes install directory is already created
1475 # We are always building modules
1477 PHONY
+= crmodverdir
1481 PHONY
+= $(objtree
)/Module.symvers
1482 $(objtree
)/Module.symvers
:
1483 @
test -e
$(objtree
)/Module.symvers ||
( \
1485 echo
" WARNING: Symbol version dump $(objtree)/Module.symvers"; \
1486 echo
" is missing; modules will have no dependencies and modversions."; \
1489 module-dirs
:= $(addprefix _module_
,$(KBUILD_EXTMOD
))
1490 PHONY
+= $(module-dirs
) modules
1491 $(module-dirs
): crmodverdir
$(objtree
)/Module.symvers
1492 $(Q
)$(MAKE
) $(build
)=$(patsubst _module_
%,%,$@
)
1494 modules
: $(module-dirs
)
1495 @
$(kecho
) ' Building modules, stage 2.';
1496 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.modpost
1498 PHONY
+= modules_install
1499 modules_install
: _emodinst_ _emodinst_post
1501 install-dir
:= $(if
$(INSTALL_MOD_DIR
),$(INSTALL_MOD_DIR
),extra
)
1504 $(Q
)mkdir
-p
$(MODLIB
)/$(install-dir
)
1505 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.modinst
1507 PHONY
+= _emodinst_post
1508 _emodinst_post
: _emodinst_
1511 clean-dirs
:= $(addprefix _clean_
,$(KBUILD_EXTMOD
))
1513 PHONY
+= $(clean-dirs
) clean
1515 $(Q
)$(MAKE
) $(clean)=$(patsubst _clean_
%,%,$@
)
1517 clean: rm-dirs
:= $(MODVERDIR
)
1518 clean: rm-files
:= $(KBUILD_EXTMOD
)/Module.symvers
1522 @echo
' Building external modules.'
1523 @echo
' Syntax: make -C path/to/kernel/src M=$$PWD target'
1525 @echo
' modules - default target, build the module(s)'
1526 @echo
' modules_install - install the module'
1527 @echo
' clean - remove generated files in module directory only'
1531 PHONY
+= prepare scripts
1534 endif # KBUILD_EXTMOD
1536 clean: $(clean-dirs
)
1539 @find
$(if
$(KBUILD_EXTMOD
), $(KBUILD_EXTMOD
), .
) $(RCS_FIND_IGNORE
) \
1540 \
( -name
'*.[oas]' -o
-name
'*.ko' -o
-name
'.*.cmd' \
1544 -o
-name
'.*.d' -o
-name
'.*.tmp' -o
-name
'*.mod.c' \
1545 -o
-name
'*.symtypes' -o
-name
'modules.order' \
1546 -o
-name modules.builtin
-o
-name
'.tmp_*.o.*' \
1547 -o
-name
'*.c.[012]*.*' \
1548 -o
-name
'*.gcno' \
) -type f
-print | xargs
rm -f
1550 # Generate tags for editors
1551 # ---------------------------------------------------------------------------
1552 quiet_cmd_tags
= GEN
$@
1553 cmd_tags
= $(CONFIG_SHELL
) $(srctree
)/scripts
/tags.sh
$@
1555 tags TAGS cscope gtags
: FORCE
1558 # Scripts to check various things for consistency
1559 # ---------------------------------------------------------------------------
1561 PHONY
+= includecheck versioncheck coccicheck namespacecheck export_report
1564 find
$(srctree
)/* $(RCS_FIND_IGNORE
) \
1565 -name
'*.[hcS]' -type f
-print |
sort \
1566 | xargs
$(PERL
) -w
$(srctree
)/scripts
/checkincludes.pl
1569 find
$(srctree
)/* $(RCS_FIND_IGNORE
) \
1570 -name
'*.[hcS]' -type f
-print |
sort \
1571 | xargs
$(PERL
) -w
$(srctree
)/scripts
/checkversion.pl
1574 $(Q
)$(CONFIG_SHELL
) $(srctree
)/scripts
/$@
1577 $(PERL
) $(srctree
)/scripts
/namespace.pl
1580 $(PERL
) $(srctree
)/scripts
/export_report.pl
1582 endif #ifeq ($(config-targets),1)
1583 endif #ifeq ($(mixed-targets),1)
1585 PHONY
+= checkstack kernelrelease kernelversion image_name
1587 # UML needs a little special treatment here. It wants to use the host
1588 # toolchain, so needs $(SUBARCH) passed to checkstack.pl. Everyone
1589 # else wants $(ARCH), including people doing cross-builds, which means
1590 # that $(SUBARCH) doesn't work here.
1592 CHECKSTACK_ARCH
:= $(SUBARCH
)
1594 CHECKSTACK_ARCH
:= $(ARCH
)
1597 $(OBJDUMP
) -d vmlinux
$$(find .
-name
'*.ko') | \
1598 $(PERL
) $(src
)/scripts
/checkstack.pl
$(CHECKSTACK_ARCH
)
1601 @echo
"$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
1604 @echo
$(KERNELVERSION
)
1607 @echo
$(KBUILD_IMAGE
)
1609 # Clear a bunch of variables before executing the submake
1611 $(Q
)mkdir
-p
$(objtree
)/tools
1612 $(Q
)$(MAKE
) LDFLAGS
= MAKEFLAGS
="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O
=$(shell cd
$(objtree
) && /bin
/pwd
) subdir
=tools
-C
$(src
)/tools
/
1615 $(Q
)mkdir
-p
$(objtree
)/tools
1616 $(Q
)$(MAKE
) LDFLAGS
= MAKEFLAGS
="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O
=$(shell cd
$(objtree
) && /bin
/pwd
) subdir
=tools
-C
$(src
)/tools
/ $*
1619 # ---------------------------------------------------------------------------
1620 # Single targets are compatible with:
1621 # - build with mixed source and output
1622 # - build with separate output dir 'make O=...'
1623 # - external modules
1625 # target-dir => where to store outputfile
1626 # build-dir => directory in kernel source tree to use
1628 ifeq ($(KBUILD_EXTMOD
),)
1629 build-dir
= $(patsubst %/,%,$(dir $@
))
1630 target-dir
= $(dir $@
)
1632 zap-slash
=$(filter-out .
,$(patsubst %/,%,$(dir $@
)))
1633 build-dir
= $(KBUILD_EXTMOD
)$(if
$(zap-slash
),/$(zap-slash
))
1634 target-dir
= $(if
$(KBUILD_EXTMOD
),$(dir $<),$(dir $@
))
1637 %.s
: %.c prepare scripts FORCE
1638 $(Q
)$(MAKE
) $(build
)=$(build-dir
) $(target-dir
)$(notdir $@
)
1639 %.i
: %.c prepare scripts FORCE
1640 $(Q
)$(MAKE
) $(build
)=$(build-dir
) $(target-dir
)$(notdir $@
)
1641 %.o
: %.c prepare scripts FORCE
1642 $(Q
)$(MAKE
) $(build
)=$(build-dir
) $(target-dir
)$(notdir $@
)
1643 %.lst
: %.c prepare scripts FORCE
1644 $(Q
)$(MAKE
) $(build
)=$(build-dir
) $(target-dir
)$(notdir $@
)
1645 %.s
: %.S prepare scripts FORCE
1646 $(Q
)$(MAKE
) $(build
)=$(build-dir
) $(target-dir
)$(notdir $@
)
1647 %.o
: %.S prepare scripts FORCE
1648 $(Q
)$(MAKE
) $(build
)=$(build-dir
) $(target-dir
)$(notdir $@
)
1649 %.symtypes
: %.c prepare scripts FORCE
1650 $(Q
)$(MAKE
) $(build
)=$(build-dir
) $(target-dir
)$(notdir $@
)
1653 /: prepare scripts FORCE
1655 $(Q
)$(MAKE
) KBUILD_MODULES
=$(if
$(CONFIG_MODULES
),1) \
1656 $(build
)=$(build-dir
)
1657 # Make sure the latest headers are built for Documentation
1658 Documentation
/ samples
/: headers_install
1659 %/: prepare scripts FORCE
1661 $(Q
)$(MAKE
) KBUILD_MODULES
=$(if
$(CONFIG_MODULES
),1) \
1662 $(build
)=$(build-dir
)
1663 %.ko
: prepare scripts FORCE
1665 $(Q
)$(MAKE
) KBUILD_MODULES
=$(if
$(CONFIG_MODULES
),1) \
1666 $(build
)=$(build-dir
) $(@
:.ko
=.o
)
1667 $(Q
)$(MAKE
) -f
$(srctree
)/scripts
/Makefile.modpost
1669 # FIXME Should go into a make.lib or something
1670 # ===========================================================================
1672 quiet_cmd_rmdirs
= $(if
$(wildcard $(rm-dirs
)),CLEAN
$(wildcard $(rm-dirs
)))
1673 cmd_rmdirs
= rm -rf
$(rm-dirs
)
1675 quiet_cmd_rmfiles
= $(if
$(wildcard $(rm-files
)),CLEAN
$(wildcard $(rm-files
)))
1676 cmd_rmfiles
= rm -f
$(rm-files
)
1678 # Run depmod only if we have System.map and depmod is executable
1679 quiet_cmd_depmod
= DEPMOD
$(KERNELRELEASE
)
1680 cmd_depmod
= $(CONFIG_SHELL
) $(srctree
)/scripts
/depmod.sh
$(DEPMOD
) \
1681 $(KERNELRELEASE
) "$(patsubst y,_,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))"
1683 # Create temporary dir for module support files
1684 # clean it up only when building all modules
1685 cmd_crmodverdir
= $(Q
)mkdir
-p
$(MODVERDIR
) \
1686 $(if
$(KBUILD_MODULES
),; rm -f
$(MODVERDIR
)/*)
1688 # read all saved command lines
1690 targets
:= $(wildcard $(sort $(targets
)))
1691 cmd_files
:= $(wildcard .
*.cmd
$(foreach f
,$(targets
),$(dir $(f
)).
$(notdir $(f
)).cmd
))
1693 ifneq ($(cmd_files
),)
1694 $(cmd_files
): ; # Do not try to update included dependency files
1695 include $(cmd_files
)
1698 endif # skip-makefile
1703 # Declare the contents of the .PHONY variable as phony. We keep that
1704 # information in a variable so we can use it in if_changed and friends.