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 # Add custom flags here to avoid conflict with updates
14 EXTRAVERSION := $(EXTRAVERSION)-omap1
16 # Do not print "Entering directory ..."
17 MAKEFLAGS += --no-print-directory
19 # We are using a recursive build, so we need to do a little thinking
20 # to get the ordering right.
22 # Most importantly: sub-Makefiles should only ever modify files in
23 # their own directory. If in some directory we have a dependency on
24 # a file in another dir (which doesn't happen often, but it's often
25 # unavoidable when linking the built-in.o targets which finally
26 # turn into vmlinux), we will call a sub make in that other dir, and
27 # after that we are sure that everything which is in that other dir
30 # The only cases where we need to modify files which have global
31 # effects are thus separated out and done before the recursive
32 # descending is started. They are now explicitly listed as the
35 # To put more focus on warnings, be less verbose as default
36 # Use 'make V=1' to see the full commands
39 ifeq ("$(origin V)", "command line")
47 # Call sparse as part of compilation of C files
48 # Use 'make C=1' to enable sparse checking
51 ifeq ("$(origin C)", "command line")
52 KBUILD_CHECKSRC = $(C)
55 ifndef KBUILD_CHECKSRC
59 # Use make M=dir to specify directory of external module to build
60 # Old syntax make ... SUBDIRS=$PWD is still supported
61 # Setting the environment variable KBUILD_EXTMOD take precedence
63 KBUILD_EXTMOD ?= $(SUBDIRS)
66 ifeq ("$(origin M)", "command line")
72 # kbuild supports saving output files in a separate directory.
73 # To locate output files in a separate directory two syntaxes are supported.
74 # In both cases the working directory must be the root of the kernel src.
76 # Use "make O=dir/to/store/output/files/"
78 # 2) Set KBUILD_OUTPUT
79 # Set the environment variable KBUILD_OUTPUT to point to the directory
80 # where the output files shall be placed.
81 # export KBUILD_OUTPUT=dir/to/store/output/files/
84 # The O= assignment takes precedence over the KBUILD_OUTPUT environment
88 # KBUILD_SRC is set on invocation of make in OBJ directory
89 # KBUILD_SRC is not intended to be used by the regular user (for now)
92 # OK, Make called in directory where kernel src resides
93 # Do we want to locate output files in a separate directory?
95 ifeq ("$(origin O)", "command line")
100 # That's our default target when none is given on the command line
104 ifneq ($(KBUILD_OUTPUT),)
105 # Invoke a second make in the output directory, passing relevant variables
106 # check that the output directory actually exists
107 saved-output := $(KBUILD_OUTPUT)
108 KBUILD_OUTPUT := $(shell cd $(KBUILD_OUTPUT) && /bin/pwd)
109 $(if $(KBUILD_OUTPUT),, \
110 $(error output directory "$(saved-output)" does not exist))
112 .PHONY: $(MAKECMDGOALS)
114 $(filter-out _all,$(MAKECMDGOALS)) _all:
115 $(if $(KBUILD_VERBOSE:1=),@)$(MAKE) -C $(KBUILD_OUTPUT) \
116 KBUILD_SRC=$(CURDIR) KBUILD_VERBOSE=$(KBUILD_VERBOSE) \
117 KBUILD_CHECK=$(KBUILD_CHECK) KBUILD_EXTMOD="$(KBUILD_EXTMOD)" \
118 -f $(CURDIR)/Makefile $@
120 # Leave processing to above invocation of make
122 endif # ifneq ($(KBUILD_OUTPUT),)
123 endif # ifeq ($(KBUILD_SRC),)
125 # We process the rest of the Makefile if this is the final invocation of make
126 ifeq ($(skip-makefile),)
128 # If building an external module we do not care about the all: rule
129 # but instead _all depend on modules
131 ifeq ($(KBUILD_EXTMOD),)
137 srctree := $(if $(KBUILD_SRC),$(KBUILD_SRC),$(CURDIR))
139 # FIXME - TOPDIR is obsolete, use srctree/objtree
146 export srctree objtree VPATH TOPDIR
149 space := $(nullstring) # end of line
151 # Take the contents of any files called localversion* and the config
152 # variable CONFIG_LOCALVERSION and append them to KERNELRELEASE. Be
153 # careful not to include files twice if building in the source
154 # directory. LOCALVERSION from the command line override all of this
156 localver := $(objtree)/localversion* $(srctree)/localversion*
157 localver := $(sort $(wildcard $(localver)))
158 # skip backup files (containing '~')
159 localver := $(foreach f, $(localver), $(if $(findstring ~, $(f)),,$(f)))
161 LOCALVERSION = $(subst $(space),, \
162 $(shell cat /dev/null $(localver)) \
163 $(patsubst "%",%,$(CONFIG_LOCALVERSION)))
165 KERNELRELEASE=$(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)$(LOCALVERSION)
167 # SUBARCH tells the usermode build what the underlying arch is. That is set
168 # first, and if a usermode build is happening, the "ARCH=um" on the command
169 # line overrides the setting of ARCH below. If a native build is happening,
170 # then ARCH is assigned, getting whatever value it gets normally, and
171 # SUBARCH is subsequently ignored.
173 SUBARCH := $(shell uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
174 -e s/arm.*/arm/ -e s/sa110/arm/ \
175 -e s/s390x/s390/ -e s/parisc64/parisc/ )
178 # Cross compiling and selecting different set of gcc/bin-utils
179 # ---------------------------------------------------------------------------
181 # When performing cross compilation for other architectures ARCH shall be set
182 # to the target architecture. (See arch/* for the possibilities).
183 # ARCH can be set during invocation of make:
185 # Another way is to have ARCH set in the environment.
186 # The default ARCH is the host where make is executed.
188 # CROSS_COMPILE specify the prefix used for all executables used
189 # during compilation. Only gcc and related bin-utils executables
190 # are prefixed with $(CROSS_COMPILE).
191 # CROSS_COMPILE can be set on the command line
192 # make CROSS_COMPILE=ia64-linux-
193 # Alternatively CROSS_COMPILE can be set in the environment.
194 # Default value for CROSS_COMPILE is not to prefix executables
195 # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
198 CROSS_COMPILE ?= arm-linux-
200 # Architecture as present in compile.h
201 UTS_MACHINE := $(ARCH)
203 # SHELL used by kbuild
204 CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
205 else if [ -x /bin/bash ]; then echo /bin/bash; \
206 else echo sh; fi ; fi)
210 HOSTCFLAGS = -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
213 # Decide whether to build built-in, modular, or both.
214 # Normally, just do built-in.
219 # If we have only "make modules", don't compile built-in objects.
220 # When we're building modules with modversions, we need to consider
221 # the built-in objects during the descend as well, in order to
222 # make sure the checksums are uptodate before we record them.
224 ifeq ($(MAKECMDGOALS),modules)
225 KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1)
228 # If we have "make <whatever> modules", compile modules
229 # in addition to whatever we do anyway.
230 # Just "make" or "make all" shall build modules as well
232 ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
236 ifeq ($(MAKECMDGOALS),)
240 export KBUILD_MODULES KBUILD_BUILTIN KBUILD_VERBOSE
241 export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD
244 # ---------------------------------------------------------------------------
246 # Normally, we echo the whole command before executing it. By making
247 # that echo $($(quiet)$(cmd)), we now have the possibility to set
248 # $(quiet) to choose other forms of output instead, e.g.
250 # quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
251 # cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
253 # If $(quiet) is empty, the whole command will be printed.
254 # If it is set to "quiet_", only the short version will be printed.
255 # If it is set to "silent_", nothing wil be printed at all, since
256 # the variable $(silent_cmd_cc_o_c) doesn't exist.
258 # A simple variant is to prefix commands with $(Q) - that's usefull
259 # for commands that shall be hidden in non-verbose mode.
263 # If KBUILD_VERBOSE equals 0 then the above command will be hidden.
264 # If KBUILD_VERBOSE equals 1 then the above command is displayed.
266 ifeq ($(KBUILD_VERBOSE),1)
274 # If the user is running make -s (silent mode), suppress echoing of
277 ifneq ($(findstring s,$(MAKEFLAGS)),)
281 export quiet Q KBUILD_VERBOSE
284 # cc support functions to be used (only) in arch/$(ARCH)/Makefile
285 # See documentation in Documentation/kbuild/makefiles.txt
288 # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
290 cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
291 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
293 # For backward compatibility
294 check_gcc = $(warning check_gcc is deprecated - use cc-option) \
295 $(call cc-option, $(1),$(2))
298 # Usage: flag := $(call cc-option-yn, -march=winchip-c6)
299 cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
300 > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
303 # Prefix align with either -falign or -malign
304 cc-option-align = $(subst -functions=0,,\
305 $(call cc-option,-falign-functions=0,-malign-functions=0))
308 # Usage gcc-ver := $(call cc-version $(CC))
309 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
310 $(if $(1), $(1), $(CC)))
313 # Look for make include files relative to root of kernel src
314 MAKEFLAGS += --include-dir=$(srctree)
316 # For maximum performance (+ possibly random breakage, uncomment
321 # Make variables (CC, etc...)
323 AS = $(CROSS_COMPILE)as
324 LD = $(CROSS_COMPILE)ld
325 CC = $(CROSS_COMPILE)gcc
327 AR = $(CROSS_COMPILE)ar
328 NM = $(CROSS_COMPILE)nm
329 STRIP = $(CROSS_COMPILE)strip
330 OBJCOPY = $(CROSS_COMPILE)objcopy
331 OBJDUMP = $(CROSS_COMPILE)objdump
333 GENKSYMS = scripts/genksyms/genksyms
334 DEPMOD = /sbin/depmod
335 KALLSYMS = scripts/kallsyms
339 CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__
341 CFLAGS_MODULE = $(MODFLAGS)
342 AFLAGS_MODULE = $(MODFLAGS)
348 # Use LINUXINCLUDE when you must reference the include/ directory.
349 # Needed to be compatible with the O= option
350 LINUXINCLUDE := -Iinclude \
351 $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include)
353 CPPFLAGS := -D__KERNEL__ $(LINUXINCLUDE)
355 CFLAGS := -Wall -Wstrict-prototypes -Wno-trigraphs \
356 -fno-strict-aliasing -fno-common \
358 AFLAGS := -D__ASSEMBLY__
360 export VERSION PATCHLEVEL SUBLEVEL EXTRAVERSION LOCALVERSION KERNELRELEASE \
361 ARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC \
362 CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL UTS_MACHINE \
363 HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
365 export CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
366 export CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
367 export AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
369 # When compiling out-of-tree modules, put MODVERDIR in the module
370 # tree rather than in the kernel tree. The kernel tree might
372 export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
374 # The temporary file to save gcc -MD generated dependencies must not
377 depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
379 # Files to ignore in find ... statements
381 RCS_FIND_IGNORE := \( -name SCCS -o -name BitKeeper -o -name .svn -o -name CVS -o -name .pc \) -prune -o
382 RCS_TAR_IGNORE := --exclude SCCS --exclude BitKeeper --exclude .svn --exclude CVS --exclude .pc
384 # ===========================================================================
385 # Rules shared between *config targets and build targets
387 # Basic helpers built in scripts/
388 .PHONY: scripts_basic
390 $(Q)$(MAKE) $(build)=scripts/basic
392 .PHONY: outputmakefile
393 # outputmakefile generate a Makefile to be placed in output directory, if
394 # using a seperate output directory. This allows convinient use
395 # of make in output directory
397 $(Q)if test ! $(srctree) -ef $(objtree); then \
398 $(CONFIG_SHELL) $(srctree)/scripts/mkmakefile \
399 $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL) \
400 > $(objtree)/Makefile; \
401 echo ' GEN $(objtree)/Makefile'; \
404 # To make sure we do not include .config for any of the *config targets
405 # catch them early, and hand them over to scripts/kconfig/Makefile
406 # It is allowed to specify more targets when calling make, including
407 # mixing *config targets and build targets.
408 # For example 'make oldconfig all'.
409 # Detect when mixed targets is specified, and make a second invocation
410 # of make so .config is not included in this case either (for *config).
412 no-dot-config-targets := clean mrproper distclean \
413 cscope TAGS tags help %docs check%
419 ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
420 ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
425 ifeq ($(KBUILD_EXTMOD),)
426 ifneq ($(filter config %config,$(MAKECMDGOALS)),)
428 ifneq ($(filter-out config %config,$(MAKECMDGOALS)),)
434 ifeq ($(mixed-targets),1)
435 # ===========================================================================
436 # We're called with mixed targets (*config and build targets).
437 # Handle them one by one.
440 $(Q)$(MAKE) -C $(srctree) KBUILD_SRC= $@
443 ifeq ($(config-targets),1)
444 # ===========================================================================
445 # *config targets only - make sure prerequisites are updated, and descend
446 # in scripts/kconfig to make the *config target
448 # Read arch specific Makefile to set KBUILD_DEFCONFIG as needed.
449 # KBUILD_DEFCONFIG may point out an alternative default configuration
450 # used for 'make defconfig'
451 include $(srctree)/arch/$(ARCH)/Makefile
452 export KBUILD_DEFCONFIG
454 config: scripts_basic outputmakefile FORCE
455 $(Q)$(MAKE) $(build)=scripts/kconfig $@
456 %config: scripts_basic outputmakefile FORCE
457 $(Q)$(MAKE) $(build)=scripts/kconfig $@
460 # ===========================================================================
461 # Build targets only - this includes vmlinux, arch specific targets, clean
462 # targets and others. In general all targets except *config targets.
464 ifeq ($(KBUILD_EXTMOD),)
465 # Additional helpers built in scripts/
466 # Carefully list dependencies so we do not try to build scripts twice
469 scripts: scripts_basic include/config/MARKER
470 $(Q)$(MAKE) $(build)=$(@)
472 scripts_basic: include/linux/autoconf.h
474 # Objects we will link into vmlinux / subdirs we need to visit
476 drivers-y := drivers/ sound/
480 endif # KBUILD_EXTMOD
482 ifeq ($(dot-config),1)
483 # In this section, we need .config
485 # Read in dependencies to all Kconfig* files, make sure to run
486 # oldconfig if changes are detected.
491 # If .config needs to be updated, it will be done via the dependency
492 # that autoconf has on .config.
493 # To avoid any implicit rule to kick in, define an empty command
496 # If .config is newer than include/linux/autoconf.h, someone tinkered
497 # with it and forgot to run make oldconfig
498 include/linux/autoconf.h: .config
499 $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig
501 # Dummy target needed, because used as prerequisite
502 include/linux/autoconf.h: ;
505 # The all: target is the default when no target is given on the
507 # This allow a user to issue only 'make' to build a kernel including modules
508 # Defaults vmlinux but it is usually overriden in the arch makefile
511 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
517 #Add align options if CONFIG_CC_* is not equal to 0
518 add-align = $(if $(filter-out 0,$($(1))),$(cc-option-align)$(2)=$($(1)))
519 CFLAGS += $(call add-align,CONFIG_CC_ALIGN_FUNCTIONS,-functions)
520 CFLAGS += $(call add-align,CONFIG_CC_ALIGN_LABELS,-labels)
521 CFLAGS += $(call add-align,CONFIG_CC_ALIGN_LOOPS,-loops)
522 CFLAGS += $(call add-align,CONFIG_CC_ALIGN_JUMPS,-jumps)
524 ifdef CONFIG_FRAME_POINTER
525 CFLAGS += -fno-omit-frame-pointer $(call cc-option,-fno-optimize-sibling-calls,)
527 CFLAGS += -fomit-frame-pointer
530 ifdef CONFIG_DEBUG_INFO
534 include $(srctree)/arch/$(ARCH)/Makefile
536 # arch Makefile may override CC so keep this after arch Makefile is included
537 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
538 CHECKFLAGS += $(NOSTDINC_FLAGS)
540 # warn about C99 declaration after statement
541 CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
543 # disable pointer signedness warnings in gcc 4.0
544 CFLAGS += $(call cc-option,-Wno-pointer-sign,)
546 # Default kernel image to build when no specific target is given.
547 # KBUILD_IMAGE may be overruled on the commandline or
548 # set in the environment
549 # Also any assignments in arch/$(ARCH)/Makefile take precedence over
551 export KBUILD_IMAGE ?= vmlinux
554 # INSTALL_PATH specifies where to place the updated kernel and system map
555 # images. Default is /boot, but you can set it to other values
556 export INSTALL_PATH ?= /boot
559 # INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
560 # relocations required by build roots. This is not defined in the
561 # makefile but the arguement can be passed to make if needed.
564 MODLIB := $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
568 ifeq ($(KBUILD_EXTMOD),)
569 core-y += kernel/ mm/ fs/ ipc/ security/ crypto/
571 vmlinux-dirs := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
572 $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
573 $(net-y) $(net-m) $(libs-y) $(libs-m)))
575 vmlinux-alldirs := $(sort $(vmlinux-dirs) $(patsubst %/,%,$(filter %/, \
577 $(core-n) $(core-) $(drivers-n) $(drivers-) \
578 $(net-n) $(net-) $(libs-n) $(libs-))))
580 init-y := $(patsubst %/, %/built-in.o, $(init-y))
581 core-y := $(patsubst %/, %/built-in.o, $(core-y))
582 drivers-y := $(patsubst %/, %/built-in.o, $(drivers-y))
583 net-y := $(patsubst %/, %/built-in.o, $(net-y))
584 libs-y1 := $(patsubst %/, %/lib.a, $(libs-y))
585 libs-y2 := $(patsubst %/, %/built-in.o, $(libs-y))
586 libs-y := $(libs-y1) $(libs-y2)
589 # ---------------------------------------------------------------------------
590 # vmlinux is build from the objects selected by $(vmlinux-init) and
591 # $(vmlinux-main). Most are built-in.o files from top-level directories
592 # in the kernel tree, others are specified in arch/$(ARCH)Makefile.
593 # Ordering when linking is important, and $(vmlinux-init) must be first.
598 # +-< $(vmlinux-init)
599 # | +--< init/version.o + more
601 # +--< $(vmlinux-main)
602 # | +--< driver/built-in.o mm/built-in.o + more
604 # +-< kallsyms.o (see description in CONFIG_KALLSYMS section)
606 # vmlinux version (uname -v) cannot be updated during normal
607 # descending-into-subdirs phase since we do not yet know if we need to
609 # Therefore this step is delayed until just before final link of vmlinux -
610 # except in the kallsyms case where it is done just before adding the
611 # symbols to the kernel.
613 # System.map is generated to document addresses of all kernel symbols
615 vmlinux-init := $(head-y) $(init-y)
616 vmlinux-main := $(core-y) $(libs-y) $(drivers-y) $(net-y)
617 vmlinux-all := $(vmlinux-init) $(vmlinux-main)
618 vmlinux-lds := arch/$(ARCH)/kernel/vmlinux.lds
620 # Rule to link vmlinux - also used during CONFIG_KALLSYMS
621 # May be overridden by arch/$(ARCH)/Makefile
622 quiet_cmd_vmlinux__ ?= LD $@
623 cmd_vmlinux__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) -o $@ \
624 -T $(vmlinux-lds) $(vmlinux-init) \
625 --start-group $(vmlinux-main) --end-group \
626 $(filter-out $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) FORCE ,$^)
628 # Generate new vmlinux version
629 quiet_cmd_vmlinux_version = GEN .version
630 cmd_vmlinux_version = set -e; \
631 . $(srctree)/scripts/mkversion > .tmp_version; \
632 mv -f .tmp_version .version; \
633 $(MAKE) $(build)=init
635 # Generate System.map
636 quiet_cmd_sysmap = SYSMAP
637 cmd_sysmap = $(CONFIG_SHELL) $(srctree)/scripts/mksysmap
640 # If CONFIG_KALLSYMS is set .version is already updated
641 # Generate System.map and verify that the content is consistent
643 define rule_vmlinux__
644 $(if $(CONFIG_KALLSYMS),,+$(call cmd,vmlinux_version))
646 $(call cmd,vmlinux__)
647 $(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
649 $(Q)$(if $($(quiet)cmd_sysmap), \
650 echo ' $($(quiet)cmd_sysmap) System.map' &&) \
651 $(cmd_sysmap) $@ System.map; \
652 if [ $$? -ne 0 ]; then \
660 ifdef CONFIG_KALLSYMS
661 # Generate section listing all symbols and add it into vmlinux $(kallsyms.o)
662 # It's a three stage process:
663 # o .tmp_vmlinux1 has all symbols and sections, but __kallsyms is
665 # Running kallsyms on that gives us .tmp_kallsyms1.o with
666 # the right size - vmlinux version (uname -v) is updated during this step
667 # o .tmp_vmlinux2 now has a __kallsyms section of the right size,
668 # but due to the added section, some addresses have shifted.
669 # From here, we generate a correct .tmp_kallsyms2.o
670 # o The correct .tmp_kallsyms2.o is linked into the final vmlinux.
671 # o Verify that the System.map from vmlinux matches the map from
672 # .tmp_vmlinux2, just in case we did not generate kallsyms correctly.
673 # o If CONFIG_KALLSYMS_EXTRA_PASS is set, do an extra pass using
674 # .tmp_vmlinux3 and .tmp_kallsyms3.o. This is only meant as a
675 # temporary bypass to allow the kernel to be built while the
676 # maintainers work out what went wrong with kallsyms.
678 ifdef CONFIG_KALLSYMS_EXTRA_PASS
684 kallsyms.o := .tmp_kallsyms$(last_kallsyms).o
686 define verify_kallsyms
687 $(Q)$(if $($(quiet)cmd_sysmap), \
688 echo ' $($(quiet)cmd_sysmap) .tmp_System.map' &&) \
689 $(cmd_sysmap) .tmp_vmlinux$(last_kallsyms) .tmp_System.map
690 $(Q)cmp -s System.map .tmp_System.map || \
691 (echo Inconsistent kallsyms data; \
692 echo Try setting CONFIG_KALLSYMS_EXTRA_PASS; \
693 rm .tmp_kallsyms* ; /bin/false )
696 # Update vmlinux version before link
697 # Use + in front of this rule to silent warning about make -j1
698 cmd_ksym_ld = $(cmd_vmlinux__)
700 +$(call cmd,vmlinux_version)
701 $(call cmd,vmlinux__)
702 $(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
705 # Generate .S file with all kernel symbols
706 quiet_cmd_kallsyms = KSYM $@
707 cmd_kallsyms = $(NM) -n $< | $(KALLSYMS) \
708 $(if $(CONFIG_KALLSYMS_ALL),--all-symbols) > $@
710 .tmp_kallsyms1.o .tmp_kallsyms2.o .tmp_kallsyms3.o: %.o: %.S scripts FORCE
711 $(call if_changed_dep,as_o_S)
713 .tmp_kallsyms%.S: .tmp_vmlinux% $(KALLSYMS)
716 # .tmp_vmlinux1 must be complete except kallsyms, so update vmlinux version
717 .tmp_vmlinux1: $(vmlinux-lds) $(vmlinux-all) FORCE
718 $(call if_changed_rule,ksym_ld)
720 .tmp_vmlinux2: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms1.o FORCE
721 $(call if_changed,vmlinux__)
723 .tmp_vmlinux3: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms2.o FORCE
724 $(call if_changed,vmlinux__)
726 # Needs to visit scripts/ before $(KALLSYMS) can be used.
727 $(KALLSYMS): scripts ;
729 endif # ifdef CONFIG_KALLSYMS
731 # vmlinux image - including updated kernel symbols
732 vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) $(kallsyms.o) FORCE
733 $(call if_changed_rule,vmlinux__)
735 # The actual objects are generated when descending,
736 # make sure no implicit rule kicks in
737 $(sort $(vmlinux-init) $(vmlinux-main)) $(vmlinux-lds): $(vmlinux-dirs) ;
739 # Handle descending into subdirectories listed in $(vmlinux-dirs)
740 # Preset locale variables to speed up the build process. Limit locale
741 # tweaks to this spot to avoid wrong language settings when running
742 # make menuconfig etc.
743 # Error messages still appears in the original language
745 .PHONY: $(vmlinux-dirs)
746 $(vmlinux-dirs): prepare-all scripts
747 $(Q)$(MAKE) $(build)=$@
749 # Things we need to do before we recursively start building the kernel
750 # or the modules are listed in "prepare-all".
751 # A multi level approach is used. prepare1 is updated first, then prepare0.
752 # prepare-all is the collection point for the prepare targets.
754 .PHONY: prepare-all prepare prepare0 prepare1 prepare2
756 # prepare2 is used to check if we are building in a separate output directory,
758 # 1) Check that make has not been executed in the kernel src $(srctree)
759 # 2) Create the include2 directory, used for the second asm symlink
762 ifneq ($(KBUILD_SRC),)
763 @echo ' Using $(srctree) as source for kernel'
764 $(Q)if [ -h $(srctree)/include/asm -o -f $(srctree)/.config ]; then \
765 echo " $(srctree) is not clean, please run 'make mrproper'";\
766 echo " in the '$(srctree)' directory.";\
769 $(Q)if [ ! -d include2 ]; then mkdir -p include2; fi;
770 $(Q)ln -fsn $(srctree)/include/asm-$(ARCH) include2/asm
773 # prepare1 creates a makefile if using a separate output directory
774 prepare1: prepare2 outputmakefile
776 prepare0: prepare1 include/linux/version.h include/asm include/config/MARKER
777 ifneq ($(KBUILD_MODULES),)
778 $(Q)rm -rf $(MODVERDIR)
779 $(Q)mkdir -p $(MODVERDIR)
782 # All the preparing..
783 prepare-all: prepare0 prepare
785 # Leave this as default for preprocessing vmlinux.lds.S, which is now
786 # done in arch/$(ARCH)/kernel/Makefile
788 export CPPFLAGS_vmlinux.lds += -P -C -U$(ARCH)
791 # ---------------------------------------------------------------------------
793 %.s: %.c scripts FORCE
794 $(Q)$(MAKE) $(build)=$(@D) $@
795 %.i: %.c scripts FORCE
796 $(Q)$(MAKE) $(build)=$(@D) $@
797 %.o: %.c scripts FORCE
798 $(Q)$(MAKE) $(build)=$(@D) $@
800 $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) $(build)=$(@D) $(@:.ko=.o)
801 $(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modpost
802 %/: scripts prepare FORCE
803 $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) $(build)=$(@D)
804 %.lst: %.c scripts FORCE
805 $(Q)$(MAKE) $(build)=$(@D) $@
806 %.s: %.S scripts FORCE
807 $(Q)$(MAKE) $(build)=$(@D) $@
808 %.o: %.S scripts FORCE
809 $(Q)$(MAKE) $(build)=$(@D) $@
811 # FIXME: The asm symlink changes when $(ARCH) changes. That's
812 # hard to detect, but I suppose "make mrproper" is a good idea
813 # before switching between archs anyway.
816 @echo ' SYMLINK $@ -> include/asm-$(ARCH)'
817 $(Q)if [ ! -d include ]; then mkdir -p include; fi;
818 @ln -fsn asm-$(ARCH) $@
820 # Split autoconf.h into include/linux/config/*
822 include/config/MARKER: include/linux/autoconf.h
823 @echo ' SPLIT include/linux/autoconf.h -> include/config/*'
824 @scripts/basic/split-include include/linux/autoconf.h include/config
827 # Generate some files
828 # ---------------------------------------------------------------------------
830 # KERNELRELEASE can change from a few different places, meaning version.h
831 # needs to be updated, so this check is forced on all builds
835 define filechk_version.h
836 if [ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt $(uts_len) ]; then \
837 echo '"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2; \
840 (echo \#define UTS_RELEASE \"$(KERNELRELEASE)\"; \
841 echo \#define LINUX_VERSION_CODE `expr $(VERSION) \\* 65536 + $(PATCHLEVEL) \\* 256 + $(SUBLEVEL)`; \
842 echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))'; \
846 include/linux/version.h: $(srctree)/Makefile FORCE
847 $(call filechk,version.h)
849 # ---------------------------------------------------------------------------
853 @echo '*** Warning: make $@ is unnecessary now.'
855 # ---------------------------------------------------------------------------
860 # By default, build modules as well
867 modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux)
868 @echo ' Building modules, stage 2.';
869 $(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modpost
872 # Target to prepare building external modules
873 .PHONY: modules_prepare
874 modules_prepare: prepare-all scripts
876 # Target to install modules
877 .PHONY: modules_install
878 modules_install: _modinst_ _modinst_post
882 @if [ -z "`$(DEPMOD) -V | grep module-init-tools`" ]; then \
883 echo "Warning: you may need to install module-init-tools"; \
884 echo "See http://www.codemonkey.org.uk/docs/post-halloween-2.6.txt";\
887 @rm -rf $(MODLIB)/kernel
888 @rm -f $(MODLIB)/source
889 @mkdir -p $(MODLIB)/kernel
890 @ln -s $(srctree) $(MODLIB)/source
891 @if [ ! $(objtree) -ef $(MODLIB)/build ]; then \
892 rm -f $(MODLIB)/build ; \
893 ln -s $(objtree) $(MODLIB)/build ; \
895 $(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modinst
897 # If System.map exists, run depmod. This deliberately does not have a
898 # dependency on System.map since that would run the dependency tree on
899 # vmlinux. This depmod is only for convenience to give the initial
900 # boot a modules.dep even before / is mounted read-write. However the
901 # boot script depmod is the master version.
902 ifeq "$(strip $(INSTALL_MOD_PATH))" ""
905 depmod_opts := -b $(INSTALL_MOD_PATH) -r
907 .PHONY: _modinst_post
908 _modinst_post: _modinst_
909 if [ -r System.map -a -x $(DEPMOD) ]; then $(DEPMOD) -ae -F System.map $(depmod_opts) $(KERNELRELEASE); fi
911 else # CONFIG_MODULES
913 # Modules not configured
914 # ---------------------------------------------------------------------------
916 modules modules_install: FORCE
918 @echo "The present kernel configuration has modules disabled."
919 @echo "Type 'make config' and enable loadable module support."
920 @echo "Then build a kernel with module support enabled."
924 endif # CONFIG_MODULES
926 # Generate asm-offsets.h
927 # ---------------------------------------------------------------------------
929 define filechk_gen-asm-offsets
931 echo "#ifndef __ASM_OFFSETS_H__"; \
932 echo "#define __ASM_OFFSETS_H__"; \
934 echo " * DO NOT MODIFY."; \
936 echo " * This file was generated by arch/$(ARCH)/Makefile"; \
940 sed -ne "/^->/{s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; s:->::; p;}"; \
947 # Cleaning is done on three levels.
948 # make clean Delete most generated files
949 # Leave enough to build external modules
950 # make mrproper Delete the current configuration, and all generated files
951 # make distclean Remove editor backup files, patch leftover files and the like
953 # Directories & files removed with 'make clean'
954 CLEAN_DIRS += $(MODVERDIR)
955 CLEAN_FILES += vmlinux System.map \
956 .tmp_kallsyms* .tmp_version .tmp_vmlinux* .tmp_System.map
958 # Directories & files removed with 'make mrproper'
959 MRPROPER_DIRS += include/config include2
960 MRPROPER_FILES += .config .config.old include/asm .version \
961 include/linux/autoconf.h include/linux/version.h \
962 Module.symvers tags TAGS cscope*
964 # clean - Delete most, but leave enough to build external modules
966 clean: rm-dirs := $(CLEAN_DIRS)
967 clean: rm-files := $(CLEAN_FILES)
968 clean-dirs := $(addprefix _clean_,$(vmlinux-alldirs))
970 .PHONY: $(clean-dirs) clean archclean
972 $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
974 clean: archclean $(clean-dirs)
977 @find . $(RCS_FIND_IGNORE) \
978 \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
979 -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \) \
980 -type f -print | xargs rm -f
982 # mrproper - Delete all generated files, including .config
984 mrproper: rm-dirs := $(wildcard $(MRPROPER_DIRS))
985 mrproper: rm-files := $(wildcard $(MRPROPER_FILES))
986 mrproper-dirs := $(addprefix _mrproper_,Documentation/DocBook scripts)
988 .PHONY: $(mrproper-dirs) mrproper archmrproper
990 $(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@)
992 mrproper: clean archmrproper $(mrproper-dirs)
1001 @find $(srctree) $(RCS_FIND_IGNORE) \
1002 \( -name '*.orig' -o -name '*.rej' -o -name '*~' \
1003 -o -name '*.bak' -o -name '#*#' -o -name '.*.orig' \
1004 -o -name '.*.rej' -o -size 0 \
1005 -o -name '*%' -o -name '.*.cmd' -o -name 'core' \) \
1006 -type f -print | xargs rm -f
1009 # Packaging of the kernel to various formats
1010 # ---------------------------------------------------------------------------
1011 # rpm target kept for backward compatibility
1012 package-dir := $(srctree)/scripts/package
1017 $(Q)$(MAKE) -f $(package-dir)/Makefile $@
1019 $(Q)$(MAKE) -f $(package-dir)/Makefile $@
1022 # Brief documentation of the typical targets used
1023 # ---------------------------------------------------------------------------
1025 boards := $(wildcard $(srctree)/arch/$(ARCH)/configs/*_defconfig)
1026 boards := $(notdir $(boards))
1029 @echo 'Cleaning targets:'
1030 @echo ' clean - remove most generated files but keep the config'
1031 @echo ' mrproper - remove all generated files + config + various backup files'
1033 @echo 'Configuration targets:'
1034 @$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
1036 @echo 'Other generic targets:'
1037 @echo ' all - Build all targets marked with [*]'
1038 @echo '* vmlinux - Build the bare kernel'
1039 @echo '* modules - Build all modules'
1040 @echo ' modules_install - Install all modules'
1041 @echo ' dir/ - Build all files in dir and below'
1042 @echo ' dir/file.[ois] - Build specified target only'
1043 @echo ' dir/file.ko - Build module including final link'
1044 @echo ' rpm - Build a kernel as an RPM package'
1045 @echo ' tags/TAGS - Generate tags file for editors'
1046 @echo ' cscope - Generate cscope index'
1048 @echo 'Static analysers'
1049 @echo ' buildcheck - List dangling references to vmlinux discarded sections'
1050 @echo ' and init sections from non-init sections'
1051 @echo ' checkstack - Generate a list of stack hogs'
1052 @echo ' namespacecheck - Name space analysis on compiled kernel'
1054 @echo 'Kernel packaging:'
1055 @$(MAKE) -f $(package-dir)/Makefile help
1057 @echo 'Documentation targets:'
1058 @$(MAKE) -f $(srctree)/Documentation/DocBook/Makefile dochelp
1060 @echo 'Architecture specific targets ($(ARCH)):'
1061 @$(if $(archhelp),$(archhelp),\
1062 echo ' No architecture specific help defined for $(ARCH)')
1065 $(foreach b, $(boards), \
1066 printf " %-24s - Build for %s\\n" $(b) $(subst _defconfig,,$(b));) \
1069 @echo ' make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
1070 @echo ' make O=dir [targets] Locate all output files in "dir", including .config'
1071 @echo ' make C=1 [targets] Check all c source with $$CHECK (sparse)'
1072 @echo ' make C=2 [targets] Force check of all c source with $$CHECK (sparse)'
1074 @echo 'Execute "make" or "make all" to build all targets marked with [*] '
1075 @echo 'For further info see the ./README file'
1078 # Documentation targets
1079 # ---------------------------------------------------------------------------
1080 %docs: scripts_basic FORCE
1081 $(Q)$(MAKE) $(build)=Documentation/DocBook $@
1083 else # KBUILD_EXTMOD
1086 # External module support.
1087 # When building external modules the kernel used as basis is considered
1088 # read-only, and no consistency checks are made and the make
1089 # system is not used on the basis kernel. If updates are required
1090 # in the basis kernel ordinary make commands (without M=...) must
1093 # The following are the only valid targets when building external
1095 # make M=dir clean Delete all automatically generated files
1096 # make M=dir modules Make all modules in specified dir
1097 # make M=dir Same as 'make M=dir modules'
1098 # make M=dir modules_install
1099 # Install the modules build in the module directory
1100 # Assumes install directory is already created
1102 # We are always building modules
1106 $(Q)mkdir -p $(MODVERDIR)
1108 .PHONY: $(objtree)/Module.symvers
1109 $(objtree)/Module.symvers:
1110 @test -e $(objtree)/Module.symvers || ( \
1112 echo " WARNING: Symbol version dump $(objtree)/Module.symvers"; \
1113 echo " is missing; modules will have no dependencies and modversions."; \
1116 module-dirs := $(addprefix _module_,$(KBUILD_EXTMOD))
1117 .PHONY: $(module-dirs) modules
1118 $(module-dirs): crmodverdir $(objtree)/Module.symvers
1119 $(Q)$(MAKE) $(build)=$(patsubst _module_%,%,$@)
1121 modules: $(module-dirs)
1122 @echo ' Building modules, stage 2.';
1123 $(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modpost
1125 .PHONY: modules_install
1127 $(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modinst
1129 clean-dirs := $(addprefix _clean_,$(KBUILD_EXTMOD))
1131 .PHONY: $(clean-dirs) clean
1133 $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
1135 clean: rm-dirs := $(MODVERDIR)
1136 clean: $(clean-dirs)
1138 @find $(KBUILD_EXTMOD) $(RCS_FIND_IGNORE) \
1139 \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
1140 -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \) \
1141 -type f -print | xargs rm -f
1144 @echo ' Building external modules.'
1145 @echo ' Syntax: make -C path/to/kernel/src M=$$PWD target'
1147 @echo ' modules - default target, build the module(s)'
1148 @echo ' modules_install - install the module'
1149 @echo ' clean - remove generated files in module directory only'
1151 endif # KBUILD_EXTMOD
1153 # Generate tags for editors
1154 # ---------------------------------------------------------------------------
1156 #We want __srctree to totally vanish out when KBUILD_OUTPUT is not set
1157 #(which is the most common case IMHO) to avoid unneeded clutter in the big tags file.
1158 #Adding $(srctree) adds about 20M on i386 to the size of the output file!
1160 ifeq ($(src),$(obj))
1163 __srctree = $(srctree)/
1167 ( find $(__srctree) $(RCS_FIND_IGNORE) \
1168 \( -name include -o -name arch \) -prune -o \
1169 -name '*.[chS]' -print; \
1170 find $(__srctree)arch/$(ARCH) $(RCS_FIND_IGNORE) \
1171 -name '*.[chS]' -print; \
1172 find $(__srctree)security/selinux/include $(RCS_FIND_IGNORE) \
1173 -name '*.[chS]' -print; \
1174 find $(__srctree)include $(RCS_FIND_IGNORE) \
1175 \( -name config -o -name 'asm-*' \) -prune \
1176 -o -name '*.[chS]' -print; \
1177 find $(__srctree)include/asm-$(ARCH) $(RCS_FIND_IGNORE) \
1178 -name '*.[chS]' -print; \
1179 find $(__srctree)include/asm-generic $(RCS_FIND_IGNORE) \
1180 -name '*.[chS]' -print )
1183 quiet_cmd_cscope-file = FILELST cscope.files
1184 cmd_cscope-file = $(all-sources) > cscope.files
1186 quiet_cmd_cscope = MAKE cscope.out
1187 cmd_cscope = cscope -k -b -q
1190 $(call cmd,cscope-file)
1193 quiet_cmd_TAGS = MAKE $@
1194 cmd_TAGS = $(all-sources) | etags -
1196 # Exuberant ctags works better with -I
1198 quiet_cmd_tags = MAKE $@
1201 CTAGSF=`ctags --version | grep -i exuberant >/dev/null && echo "-I __initdata,__exitdata,EXPORT_SYMBOL,EXPORT_SYMBOL_GPL --extra=+f"`; \
1202 $(all-sources) | xargs ctags $$CTAGSF -a
1212 # Scripts to check various things for consistency
1213 # ---------------------------------------------------------------------------
1216 find * $(RCS_FIND_IGNORE) \
1217 -name '*.[hcS]' -type f -print | sort \
1218 | xargs $(PERL) -w scripts/checkconfig.pl
1221 find * $(RCS_FIND_IGNORE) \
1222 -name '*.[hcS]' -type f -print | sort \
1223 | xargs $(PERL) -w scripts/checkincludes.pl
1226 find * $(RCS_FIND_IGNORE) \
1227 -name '*.[hcS]' -type f -print | sort \
1228 | xargs $(PERL) -w scripts/checkversion.pl
1231 $(PERL) $(srctree)/scripts/reference_discarded.pl
1232 $(PERL) $(srctree)/scripts/reference_init.pl
1235 $(PERL) $(srctree)/scripts/namespace.pl
1237 endif #ifeq ($(config-targets),1)
1238 endif #ifeq ($(mixed-targets),1)
1242 $(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
1243 $(PERL) $(src)/scripts/checkstack.pl $(ARCH)
1246 @echo $(KERNELRELEASE)
1248 # FIXME Should go into a make.lib or something
1249 # ===========================================================================
1251 quiet_cmd_rmdirs = $(if $(wildcard $(rm-dirs)),CLEAN $(wildcard $(rm-dirs)))
1252 cmd_rmdirs = rm -rf $(rm-dirs)
1254 quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN $(wildcard $(rm-files)))
1255 cmd_rmfiles = rm -f $(rm-files)
1258 a_flags = -Wp,-MD,$(depfile) $(AFLAGS) $(AFLAGS_KERNEL) \
1259 $(NOSTDINC_FLAGS) $(CPPFLAGS) \
1260 $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(*F).o)
1262 quiet_cmd_as_o_S = AS $@
1263 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
1265 # read all saved command lines
1267 targets := $(wildcard $(sort $(targets)))
1268 cmd_files := $(wildcard .*.cmd $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
1270 ifneq ($(cmd_files),)
1271 $(cmd_files): ; # Do not try to update included dependency files
1272 include $(cmd_files)
1275 # Execute command and generate cmd file
1276 if_changed = $(if $(strip $? \
1277 $(filter-out $(cmd_$(1)),$(cmd_$@))\
1278 $(filter-out $(cmd_$@),$(cmd_$(1)))),\
1280 $(if $($(quiet)cmd_$(1)),echo ' $(subst ','\'',$($(quiet)cmd_$(1)))';) \
1282 echo 'cmd_$@ := $(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).cmd)
1285 # execute the command and also postprocess generated .d dependencies
1287 if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\
1288 $(filter-out $(cmd_$(1)),$(cmd_$@))\
1289 $(filter-out $(cmd_$@),$(cmd_$(1)))),\
1291 $(if $($(quiet)cmd_$(1)),echo ' $(subst ','\'',$($(quiet)cmd_$(1)))';) \
1293 scripts/basic/fixdep $(depfile) $@ '$(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).tmp; \
1295 mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
1297 # Usage: $(call if_changed_rule,foo)
1298 # will check if $(cmd_foo) changed, or any of the prequisites changed,
1299 # and if so will execute $(rule_foo)
1301 if_changed_rule = $(if $(strip $? \
1302 $(filter-out $(cmd_$(1)),$(cmd_$(@F)))\
1303 $(filter-out $(cmd_$(@F)),$(cmd_$(1)))),\
1306 # If quiet is set, only print short version of command
1308 cmd = @$(if $($(quiet)cmd_$(1)),echo ' $($(quiet)cmd_$(1))' &&) $(cmd_$(1))
1310 # filechk is used to check if the content of a generated file is updated.
1312 # define filechk_sample
1313 # echo $KERNELRELEASE
1315 # version.h : Makefile
1316 # $(call filechk,sample)
1317 # The rule defined shall write to stdout the content of the new file.
1318 # The existing file will be compared with the new one.
1319 # - If no file exist it is created
1320 # - If the content differ the new file is used
1321 # - If they are equal no change, and no timestamp update
1326 mkdir -p $(dir $@); \
1327 $(filechk_$(1)) < $< > $@.tmp; \
1328 if [ -r $@ ] && cmp -s $@ $@.tmp; then \
1336 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=dir
1338 # $(Q)$(MAKE) $(build)=dir
1339 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
1341 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=dir
1343 # $(Q)$(MAKE) $(clean)=dir
1344 clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj
1346 # $(call descend,<dir>,<target>)
1347 # Recursively call a sub-make in <dir> with target <target>
1348 # Usage is deprecated, because make does not see this as an invocation of make.
1349 descend =$(Q)$(MAKE) -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj=$(1) $(2)
1351 endif # skip-makefile