Makefile

   1 VERSION = 3
   2 PATCHLEVEL = 4
   3 SUBLEVEL = 0
   4 EXTRAVERSION = -rc1
   5 NAME = Saber-toothed Squirrel
   6
   7 # *DOCUMENTATION*
   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.
  12
  13 # Do not:
  14 # o  use make's built-in rules and variables
  15 #    (this increases performance and avoids hard-to-debug behaviour);
  16 # o  print "Entering directory ...";
  17 MAKEFLAGS += -rR --no-print-directory
  18
  19 # Avoid funny character set dependencies
  20 unexport LC_ALL
  21 LC_COLLATE=C
  22 LC_NUMERIC=C
  23 export LC_COLLATE LC_NUMERIC
  24
  25 # We are using a recursive build, so we need to do a little thinking
  26 # to get the ordering right.
  27 #
  28 # Most importantly: sub-Makefiles should only ever modify files in
  29 # their own directory. If in some directory we have a dependency on
  30 # a file in another dir (which doesn't happen often, but it's often
  31 # unavoidable when linking the built-in.o targets which finally
  32 # turn into vmlinux), we will call a sub make in that other dir, and
  33 # after that we are sure that everything which is in that other dir
  34 # is now up to date.
  35 #
  36 # The only cases where we need to modify files which have global
  37 # effects are thus separated out and done before the recursive
  38 # descending is started. They are now explicitly listed as the
  39 # prepare rule.
  40
  41 # To put more focus on warnings, be less verbose as default
  42 # Use 'make V=1' to see the full commands
  43
  44 ifeq ("$(origin V)", "command line")
  45   KBUILD_VERBOSE = $(V)
  46 endif
  47 ifndef KBUILD_VERBOSE
  48   KBUILD_VERBOSE = 0
  49 endif
  50
  51 # Call a source code checker (by default, "sparse") as part of the
  52 # C compilation.
  53 #
  54 # Use 'make C=1' to enable checking of only re-compiled files.
  55 # Use 'make C=2' to enable checking of *all* source files, regardless
  56 # of whether they are re-compiled or not.
  57 #
  58 # See the file "Documentation/sparse.txt" for more details, including
  59 # where to get the "sparse" utility.
  60
  61 ifeq ("$(origin C)", "command line")
  62   KBUILD_CHECKSRC = $(C)
  63 endif
  64 ifndef KBUILD_CHECKSRC
  65   KBUILD_CHECKSRC = 0
  66 endif
  67
  68 # Use make M=dir to specify directory of external module to build
  69 # Old syntax make ... SUBDIRS=$PWD is still supported
  70 # Setting the environment variable KBUILD_EXTMOD take precedence
  71 ifdef SUBDIRS
  72   KBUILD_EXTMOD ?= $(SUBDIRS)
  73 endif
  74
  75 ifeq ("$(origin M)", "command line")
  76   KBUILD_EXTMOD := $(M)
  77 endif
  78
  79 # kbuild supports saving output files in a separate directory.
  80 # To locate output files in a separate directory two syntaxes are supported.
  81 # In both cases the working directory must be the root of the kernel src.
  82 # 1) O=
  83 # Use "make O=dir/to/store/output/files/"
  84 #
  85 # 2) Set KBUILD_OUTPUT
  86 # Set the environment variable KBUILD_OUTPUT to point to the directory
  87 # where the output files shall be placed.
  88 # export KBUILD_OUTPUT=dir/to/store/output/files/
  89 # make
  90 #
  91 # The O= assignment takes precedence over the KBUILD_OUTPUT environment
  92 # variable.
  93
  94
  95 # KBUILD_SRC is set on invocation of make in OBJ directory
  96 # KBUILD_SRC is not intended to be used by the regular user (for now)
  97 ifeq ($(KBUILD_SRC),)
  98
  99 # OK, Make called in directory where kernel src resides
 100 # Do we want to locate output files in a separate directory?
 101 ifeq ("$(origin O)", "command line")
 102   KBUILD_OUTPUT := $(O)
 103 endif
 104
 105 ifeq ("$(origin W)", "command line")
 106   export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W)
 107 endif
 108
 109 # That's our default target when none is given on the command line
 110 PHONY := _all
 111 _all:
 112
 113 # Cancel implicit rules on top Makefile
 114 $(CURDIR)/Makefile Makefile: ;
 115
 116 ifneq ($(KBUILD_OUTPUT),)
 117 # Invoke a second make in the output directory, passing relevant variables
 118 # check that the output directory actually exists
 119 saved-output := $(KBUILD_OUTPUT)
 120 KBUILD_OUTPUT := $(shell cd $(KBUILD_OUTPUT) && /bin/pwd)
 121 $(if $(KBUILD_OUTPUT),, \
 122      $(error output directory "$(saved-output)" does not exist))
 123
 124 PHONY += $(MAKECMDGOALS) sub-make
 125
 126 $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
 127         $(Q)@:
 128
 129 sub-make: FORCE
 130         $(if $(KBUILD_VERBOSE:1=),@)$(MAKE) -C $(KBUILD_OUTPUT) \
 131         KBUILD_SRC=$(CURDIR) \
 132         KBUILD_EXTMOD="$(KBUILD_EXTMOD)" -f $(CURDIR)/Makefile \
 133         $(filter-out _all sub-make,$(MAKECMDGOALS))
 134
 135 # Leave processing to above invocation of make
 136 skip-makefile := 1
 137 endif # ifneq ($(KBUILD_OUTPUT),)
 138 endif # ifeq ($(KBUILD_SRC),)
 139
 140 # We process the rest of the Makefile if this is the final invocation of make
 141 ifeq ($(skip-makefile),)
 142
 143 # If building an external module we do not care about the all: rule
 144 # but instead _all depend on modules
 145 PHONY += all
 146 ifeq ($(KBUILD_EXTMOD),)
 147 _all: all
 148 else
 149 _all: modules
 150 endif
 151
 152 srctree         := $(if $(KBUILD_SRC),$(KBUILD_SRC),$(CURDIR))
 153 objtree         := $(CURDIR)
 154 src             := $(srctree)
 155 obj             := $(objtree)
 156
 157 VPATH           := $(srctree)$(if $(KBUILD_EXTMOD),:$(KBUILD_EXTMOD))
 158
 159 export srctree objtree VPATH
 160
 161
 162 # SUBARCH tells the usermode build what the underlying arch is.  That is set
 163 # first, and if a usermode build is happening, the "ARCH=um" on the command
 164 # line overrides the setting of ARCH below.  If a native build is happening,
 165 # then ARCH is assigned, getting whatever value it gets normally, and
 166 # SUBARCH is subsequently ignored.
 167
 168 SUBARCH := $(shell uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
 169                                   -e s/arm.*/arm/ -e s/sa110/arm/ \
 170                                   -e s/s390x/s390/ -e s/parisc64/parisc/ \
 171                                   -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
 172                                   -e s/sh[234].*/sh/ )
 173
 174 # Cross compiling and selecting different set of gcc/bin-utils
 175 # ---------------------------------------------------------------------------
 176 #
 177 # When performing cross compilation for other architectures ARCH shall be set
 178 # to the target architecture. (See arch/* for the possibilities).
 179 # ARCH can be set during invocation of make:
 180 # make ARCH=ia64
 181 # Another way is to have ARCH set in the environment.
 182 # The default ARCH is the host where make is executed.
 183
 184 # CROSS_COMPILE specify the prefix used for all executables used
 185 # during compilation. Only gcc and related bin-utils executables
 186 # are prefixed with $(CROSS_COMPILE).
 187 # CROSS_COMPILE can be set on the command line
 188 # make CROSS_COMPILE=ia64-linux-
 189 # Alternatively CROSS_COMPILE can be set in the environment.
 190 # A third alternative is to store a setting in .config so that plain
 191 # "make" in the configured kernel build directory always uses that.
 192 # Default value for CROSS_COMPILE is not to prefix executables
 193 # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
 194 export KBUILD_BUILDHOST := $(SUBARCH)
 195 ARCH            ?= $(SUBARCH)
 196 CROSS_COMPILE   ?= $(CONFIG_CROSS_COMPILE:"%"=%)
 197
 198 # Architecture as present in compile.h
 199 UTS_MACHINE     := $(ARCH)
 200 SRCARCH         := $(ARCH)
 201
 202 # Additional ARCH settings for x86
 203 ifeq ($(ARCH),i386)
 204         SRCARCH := x86
 205 endif
 206 ifeq ($(ARCH),x86_64)
 207         SRCARCH := x86
 208 endif
 209
 210 # Additional ARCH settings for sparc
 211 ifeq ($(ARCH),sparc32)
 212        SRCARCH := sparc
 213 endif
 214 ifeq ($(ARCH),sparc64)
 215        SRCARCH := sparc
 216 endif
 217
 218 # Additional ARCH settings for sh
 219 ifeq ($(ARCH),sh64)
 220        SRCARCH := sh
 221 endif
 222
 223 # Additional ARCH settings for tile
 224 ifeq ($(ARCH),tilepro)
 225        SRCARCH := tile
 226 endif
 227 ifeq ($(ARCH),tilegx)
 228        SRCARCH := tile
 229 endif
 230
 231 # Where to locate arch specific headers
 232 hdr-arch  := $(SRCARCH)
 233
 234 KCONFIG_CONFIG  ?= .config
 235 export KCONFIG_CONFIG
 236
 237 # SHELL used by kbuild
 238 CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
 239           else if [ -x /bin/bash ]; then echo /bin/bash; \
 240           else echo sh; fi ; fi)
 241
 242 HOSTCC       = gcc
 243 HOSTCXX      = g++
 244 HOSTCFLAGS   = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer
 245 HOSTCXXFLAGS = -O2
 246
 247 # Decide whether to build built-in, modular, or both.
 248 # Normally, just do built-in.
 249
 250 KBUILD_MODULES :=
 251 KBUILD_BUILTIN := 1
 252
 253 #       If we have only "make modules", don't compile built-in objects.
 254 #       When we're building modules with modversions, we need to consider
 255 #       the built-in objects during the descend as well, in order to
 256 #       make sure the checksums are up to date before we record them.
 257
 258 ifeq ($(MAKECMDGOALS),modules)
 259   KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1)
 260 endif
 261
 262 #       If we have "make <whatever> modules", compile modules
 263 #       in addition to whatever we do anyway.
 264 #       Just "make" or "make all" shall build modules as well
 265
 266 ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
 267   KBUILD_MODULES := 1
 268 endif
 269
 270 ifeq ($(MAKECMDGOALS),)
 271   KBUILD_MODULES := 1
 272 endif
 273
 274 export KBUILD_MODULES KBUILD_BUILTIN
 275 export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD
 276
 277 # Beautify output
 278 # ---------------------------------------------------------------------------
 279 #
 280 # Normally, we echo the whole command before executing it. By making
 281 # that echo $($(quiet)$(cmd)), we now have the possibility to set
 282 # $(quiet) to choose other forms of output instead, e.g.
 283 #
 284 #         quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
 285 #         cmd_cc_o_c       = $(CC) $(c_flags) -c -o $@ $<
 286 #
 287 # If $(quiet) is empty, the whole command will be printed.
 288 # If it is set to "quiet_", only the short version will be printed.
 289 # If it is set to "silent_", nothing will be printed at all, since
 290 # the variable $(silent_cmd_cc_o_c) doesn't exist.
 291 #
 292 # A simple variant is to prefix commands with $(Q) - that's useful
 293 # for commands that shall be hidden in non-verbose mode.
 294 #
 295 #       $(Q)ln $@ :<
 296 #
 297 # If KBUILD_VERBOSE equals 0 then the above command will be hidden.
 298 # If KBUILD_VERBOSE equals 1 then the above command is displayed.
 299
 300 ifeq ($(KBUILD_VERBOSE),1)
 301   quiet =
 302   Q =
 303 else
 304   quiet=quiet_
 305   Q = @
 306 endif
 307
 308 # If the user is running make -s (silent mode), suppress echoing of
 309 # commands
 310
 311 ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
 312   quiet=silent_
 313 endif
 314
 315 export quiet Q KBUILD_VERBOSE
 316
 317
 318 # Look for make include files relative to root of kernel src
 319 MAKEFLAGS += --include-dir=$(srctree)
 320
 321 # We need some generic definitions (do not try to remake the file).
 322 $(srctree)/scripts/Kbuild.include: ;
 323 include $(srctree)/scripts/Kbuild.include
 324
 325 # Make variables (CC, etc...)
 326
 327 AS              = $(CROSS_COMPILE)as
 328 LD              = $(CROSS_COMPILE)ld
 329 CC              = $(CROSS_COMPILE)gcc
 330 CPP             = $(CC) -E
 331 AR              = $(CROSS_COMPILE)ar
 332 NM              = $(CROSS_COMPILE)nm
 333 STRIP           = $(CROSS_COMPILE)strip
 334 OBJCOPY         = $(CROSS_COMPILE)objcopy
 335 OBJDUMP         = $(CROSS_COMPILE)objdump
 336 AWK             = awk
 337 GENKSYMS        = scripts/genksyms/genksyms
 338 INSTALLKERNEL  := installkernel
 339 DEPMOD          = /sbin/depmod
 340 KALLSYMS        = scripts/kallsyms
 341 PERL            = perl
 342 CHECK           = sparse
 343
 344 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
 345                   -Wbitwise -Wno-return-void $(CF)
 346 CFLAGS_MODULE   =
 347 AFLAGS_MODULE   =
 348 LDFLAGS_MODULE  =
 349 CFLAGS_KERNEL   =
 350 AFLAGS_KERNEL   =
 351 CFLAGS_GCOV     = -fprofile-arcs -ftest-coverage
 352
 353
 354 # Use LINUXINCLUDE when you must reference the include/ directory.
 355 # Needed to be compatible with the O= option
 356 LINUXINCLUDE    := -I$(srctree)/arch/$(hdr-arch)/include \
 357                    -Iarch/$(hdr-arch)/include/generated -Iinclude \
 358                    $(if $(KBUILD_SRC), -I$(srctree)/include) \
 359                    -include $(srctree)/include/linux/kconfig.h
 360
 361 KBUILD_CPPFLAGS := -D__KERNEL__
 362
 363 KBUILD_CFLAGS   := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
 364                    -fno-strict-aliasing -fno-common \
 365                    -Werror-implicit-function-declaration \
 366                    -Wno-format-security \
 367                    -fno-delete-null-pointer-checks
 368 KBUILD_AFLAGS_KERNEL :=
 369 KBUILD_CFLAGS_KERNEL :=
 370 KBUILD_AFLAGS   := -D__ASSEMBLY__
 371 KBUILD_AFLAGS_MODULE  := -DMODULE
 372 KBUILD_CFLAGS_MODULE  := -DMODULE
 373 KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
 374
 375 # Read KERNELRELEASE from include/config/kernel.release (if it exists)
 376 KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
 377 KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
 378
 379 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
 380 export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 381 export CPP AR NM STRIP OBJCOPY OBJDUMP
 382 export MAKE AWK GENKSYMS INSTALLKERNEL PERL UTS_MACHINE
 383 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 384
 385 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
 386 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV
 387 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 388 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 389 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
 390 export KBUILD_ARFLAGS
 391
 392 # When compiling out-of-tree modules, put MODVERDIR in the module
 393 # tree rather than in the kernel tree. The kernel tree might
 394 # even be read-only.
 395 export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
 396
 397 # Files to ignore in find ... statements
 398
 399 RCS_FIND_IGNORE := \( -name SCCS -o -name BitKeeper -o -name .svn -o -name CVS -o -name .pc -o -name .hg -o -name .git \) -prune -o
 400 export RCS_TAR_IGNORE := --exclude SCCS --exclude BitKeeper --exclude .svn --exclude CVS --exclude .pc --exclude .hg --exclude .git
 401
 402 # ===========================================================================
 403 # Rules shared between *config targets and build targets
 404
 405 # Basic helpers built in scripts/
 406 PHONY += scripts_basic
 407 scripts_basic:
 408         $(Q)$(MAKE) $(build)=scripts/basic
 409         $(Q)rm -f .tmp_quiet_recordmcount
 410
 411 # To avoid any implicit rule to kick in, define an empty command.
 412 scripts/basic/%: scripts_basic ;
 413
 414 PHONY += outputmakefile
 415 # outputmakefile generates a Makefile in the output directory, if using a
 416 # separate output directory. This allows convenient use of make in the
 417 # output directory.
 418 outputmakefile:
 419 ifneq ($(KBUILD_SRC),)
 420         $(Q)ln -fsn $(srctree) source
 421         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile \
 422             $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)
 423 endif
 424
 425 # Support for using generic headers in asm-generic
 426 PHONY += asm-generic
 427 asm-generic:
 428         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \
 429                     obj=arch/$(SRCARCH)/include/generated/asm
 430
 431 # To make sure we do not include .config for any of the *config targets
 432 # catch them early, and hand them over to scripts/kconfig/Makefile
 433 # It is allowed to specify more targets when calling make, including
 434 # mixing *config targets and build targets.
 435 # For example 'make oldconfig all'.
 436 # Detect when mixed targets is specified, and make a second invocation
 437 # of make so .config is not included in this case either (for *config).
 438
 439 no-dot-config-targets := clean mrproper distclean \
 440                          cscope gtags TAGS tags help %docs check% coccicheck \
 441                          include/linux/version.h headers_% archheaders \
 442                          kernelversion %src-pkg
 443
 444 config-targets := 0
 445 mixed-targets  := 0
 446 dot-config     := 1
 447
 448 ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
 449         ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
 450                 dot-config := 0
 451         endif
 452 endif
 453
 454 ifeq ($(KBUILD_EXTMOD),)
 455         ifneq ($(filter config %config,$(MAKECMDGOALS)),)
 456                 config-targets := 1
 457                 ifneq ($(filter-out config %config,$(MAKECMDGOALS)),)
 458                         mixed-targets := 1
 459                 endif
 460         endif
 461 endif
 462
 463 ifeq ($(mixed-targets),1)
 464 # ===========================================================================
 465 # We're called with mixed targets (*config and build targets).
 466 # Handle them one by one.
 467
 468 %:: FORCE
 469         $(Q)$(MAKE) -C $(srctree) KBUILD_SRC= $@
 470
 471 else
 472 ifeq ($(config-targets),1)
 473 # ===========================================================================
 474 # *config targets only - make sure prerequisites are updated, and descend
 475 # in scripts/kconfig to make the *config target
 476
 477 # Read arch specific Makefile to set KBUILD_DEFCONFIG as needed.
 478 # KBUILD_DEFCONFIG may point out an alternative default configuration
 479 # used for 'make defconfig'
 480 include $(srctree)/arch/$(SRCARCH)/Makefile
 481 export KBUILD_DEFCONFIG KBUILD_KCONFIG
 482
 483 config: scripts_basic outputmakefile FORCE
 484         $(Q)mkdir -p include/linux include/config
 485         $(Q)$(MAKE) $(build)=scripts/kconfig $@
 486
 487 %config: scripts_basic outputmakefile FORCE
 488         $(Q)mkdir -p include/linux include/config
 489         $(Q)$(MAKE) $(build)=scripts/kconfig $@
 490
 491 else
 492 # ===========================================================================
 493 # Build targets only - this includes vmlinux, arch specific targets, clean
 494 # targets and others. In general all targets except *config targets.
 495
 496 ifeq ($(KBUILD_EXTMOD),)
 497 # Additional helpers built in scripts/
 498 # Carefully list dependencies so we do not try to build scripts twice
 499 # in parallel
 500 PHONY += scripts
 501 scripts: scripts_basic include/config/auto.conf include/config/tristate.conf
 502         $(Q)$(MAKE) $(build)=$(@)
 503
 504 # Objects we will link into vmlinux / subdirs we need to visit
 505 init-y          := init/
 506 drivers-y       := drivers/ sound/ firmware/
 507 net-y           := net/
 508 libs-y          := lib/
 509 core-y          := usr/
 510 endif # KBUILD_EXTMOD
 511
 512 ifeq ($(dot-config),1)
 513 # Read in config
 514 -include include/config/auto.conf
 515
 516 ifeq ($(KBUILD_EXTMOD),)
 517 # Read in dependencies to all Kconfig* files, make sure to run
 518 # oldconfig if changes are detected.
 519 -include include/config/auto.conf.cmd
 520
 521 # To avoid any implicit rule to kick in, define an empty command
 522 $(KCONFIG_CONFIG) include/config/auto.conf.cmd: ;
 523
 524 # If .config is newer than include/config/auto.conf, someone tinkered
 525 # with it and forgot to run make oldconfig.
 526 # if auto.conf.cmd is missing then we are probably in a cleaned tree so
 527 # we execute the config step to be sure to catch updated Kconfig files
 528 include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd
 529         $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig
 530 else
 531 # external modules needs include/generated/autoconf.h and include/config/auto.conf
 532 # but do not care if they are up-to-date. Use auto.conf to trigger the test
 533 PHONY += include/config/auto.conf
 534
 535 include/config/auto.conf:
 536         $(Q)test -e include/generated/autoconf.h -a -e $@ || (          \
 537         echo;                                                           \
 538         echo "  ERROR: Kernel configuration is invalid.";               \
 539         echo "         include/generated/autoconf.h or $@ are missing.";\
 540         echo "         Run 'make oldconfig && make prepare' on kernel src to fix it.";  \
 541         echo;                                                           \
 542         /bin/false)
 543
 544 endif # KBUILD_EXTMOD
 545
 546 else
 547 # Dummy target needed, because used as prerequisite
 548 include/config/auto.conf: ;
 549 endif # $(dot-config)
 550
 551 # The all: target is the default when no target is given on the
 552 # command line.
 553 # This allow a user to issue only 'make' to build a kernel including modules
 554 # Defaults to vmlinux, but the arch makefile usually adds further targets
 555 all: vmlinux
 556
 557 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 558 KBUILD_CFLAGS   += -Os
 559 else
 560 KBUILD_CFLAGS   += -O2
 561 endif
 562
 563 include $(srctree)/arch/$(SRCARCH)/Makefile
 564
 565 ifneq ($(CONFIG_FRAME_WARN),0)
 566 KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
 567 endif
 568
 569 # Force gcc to behave correct even for buggy distributions
 570 ifndef CONFIG_CC_STACKPROTECTOR
 571 KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
 572 endif
 573
 574 # This warning generated too much noise in a regular build.
 575 # Use make W=1 to enable this warning (see scripts/Makefile.build)
 576 KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
 577
 578 ifdef CONFIG_FRAME_POINTER
 579 KBUILD_CFLAGS   += -fno-omit-frame-pointer -fno-optimize-sibling-calls
 580 else
 581 # Some targets (ARM with Thumb2, for example), can't be built with frame
 582 # pointers.  For those, we don't have FUNCTION_TRACER automatically
 583 # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
 584 # incompatible with -fomit-frame-pointer with current GCC, so we don't use
 585 # -fomit-frame-pointer with FUNCTION_TRACER.
 586 ifndef CONFIG_FUNCTION_TRACER
 587 KBUILD_CFLAGS   += -fomit-frame-pointer
 588 endif
 589 endif
 590
 591 ifdef CONFIG_DEBUG_INFO
 592 KBUILD_CFLAGS   += -g
 593 KBUILD_AFLAGS   += -gdwarf-2
 594 endif
 595
 596 ifdef CONFIG_DEBUG_INFO_REDUCED
 597 KBUILD_CFLAGS   += $(call cc-option, -femit-struct-debug-baseonly)
 598 endif
 599
 600 ifdef CONFIG_FUNCTION_TRACER
 601 KBUILD_CFLAGS   += -pg
 602 ifdef CONFIG_DYNAMIC_FTRACE
 603         ifdef CONFIG_HAVE_C_RECORDMCOUNT
 604                 BUILD_C_RECORDMCOUNT := y
 605                 export BUILD_C_RECORDMCOUNT
 606         endif
 607 endif
 608 endif
 609
 610 # We trigger additional mismatches with less inlining
 611 ifdef CONFIG_DEBUG_SECTION_MISMATCH
 612 KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once)
 613 endif
 614
 615 # arch Makefile may override CC so keep this after arch Makefile is included
 616 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 617 CHECKFLAGS     += $(NOSTDINC_FLAGS)
 618
 619 # warn about C99 declaration after statement
 620 KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
 621
 622 # disable pointer signed / unsigned warnings in gcc 4.0
 623 KBUILD_CFLAGS += $(call cc-disable-warning, pointer-sign)
 624
 625 # disable invalid "can't wrap" optimizations for signed / pointers
 626 KBUILD_CFLAGS   += $(call cc-option,-fno-strict-overflow)
 627
 628 # conserve stack if available
 629 KBUILD_CFLAGS   += $(call cc-option,-fconserve-stack)
 630
 631 # use the deterministic mode of AR if available
 632 KBUILD_ARFLAGS := $(call ar-option,D)
 633
 634 # check for 'asm goto'
 635 ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
 636         KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
 637 endif
 638
 639 # Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
 640 # But warn user when we do so
 641 warn-assign = \
 642 $(warning "WARNING: Appending $$K$(1) ($(K$(1))) from $(origin K$(1)) to kernel $$$(1)")
 643
 644 ifneq ($(KCPPFLAGS),)
 645         $(call warn-assign,CPPFLAGS)
 646         KBUILD_CPPFLAGS += $(KCPPFLAGS)
 647 endif
 648 ifneq ($(KAFLAGS),)
 649         $(call warn-assign,AFLAGS)
 650         KBUILD_AFLAGS += $(KAFLAGS)
 651 endif
 652 ifneq ($(KCFLAGS),)
 653         $(call warn-assign,CFLAGS)
 654         KBUILD_CFLAGS += $(KCFLAGS)
 655 endif
 656
 657 # Use --build-id when available.
 658 LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
 659                               $(call cc-ldoption, -Wl$(comma)--build-id,))
 660 KBUILD_LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
 661 LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)
 662
 663 ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
 664 LDFLAGS_vmlinux += $(call ld-option, -X,)
 665 endif
 666
 667 # Default kernel image to build when no specific target is given.
 668 # KBUILD_IMAGE may be overruled on the command line or
 669 # set in the environment
 670 # Also any assignments in arch/$(ARCH)/Makefile take precedence over
 671 # this default value
 672 export KBUILD_IMAGE ?= vmlinux
 673
 674 #
 675 # INSTALL_PATH specifies where to place the updated kernel and system map
 676 # images. Default is /boot, but you can set it to other values
 677 export  INSTALL_PATH ?= /boot
 678
 679 #
 680 # INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
 681 # relocations required by build roots.  This is not defined in the
 682 # makefile but the argument can be passed to make if needed.
 683 #
 684
 685 MODLIB  = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
 686 export MODLIB
 687
 688 #
 689 #  INSTALL_MOD_STRIP, if defined, will cause modules to be
 690 #  stripped after they are installed.  If INSTALL_MOD_STRIP is '1', then
 691 #  the default option --strip-debug will be used.  Otherwise,
 692 #  INSTALL_MOD_STRIP value will be used as the options to the strip command.
 693
 694 ifdef INSTALL_MOD_STRIP
 695 ifeq ($(INSTALL_MOD_STRIP),1)
 696 mod_strip_cmd = $(STRIP) --strip-debug
 697 else
 698 mod_strip_cmd = $(STRIP) $(INSTALL_MOD_STRIP)
 699 endif # INSTALL_MOD_STRIP=1
 700 else
 701 mod_strip_cmd = true
 702 endif # INSTALL_MOD_STRIP
 703 export mod_strip_cmd
 704
 705
 706 ifeq ($(KBUILD_EXTMOD),)
 707 core-y          += kernel/ mm/ fs/ ipc/ security/ crypto/ block/
 708
 709 vmlinux-dirs    := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
 710                      $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
 711                      $(net-y) $(net-m) $(libs-y) $(libs-m)))
 712
 713 vmlinux-alldirs := $(sort $(vmlinux-dirs) $(patsubst %/,%,$(filter %/, \
 714                      $(init-n) $(init-) \
 715                      $(core-n) $(core-) $(drivers-n) $(drivers-) \
 716                      $(net-n)  $(net-)  $(libs-n)    $(libs-))))
 717
 718 init-y          := $(patsubst %/, %/built-in.o, $(init-y))
 719 core-y          := $(patsubst %/, %/built-in.o, $(core-y))
 720 drivers-y       := $(patsubst %/, %/built-in.o, $(drivers-y))
 721 net-y           := $(patsubst %/, %/built-in.o, $(net-y))
 722 libs-y1         := $(patsubst %/, %/lib.a, $(libs-y))
 723 libs-y2         := $(patsubst %/, %/built-in.o, $(libs-y))
 724 libs-y          := $(libs-y1) $(libs-y2)
 725
 726 # Build vmlinux
 727 # ---------------------------------------------------------------------------
 728 # vmlinux is built from the objects selected by $(vmlinux-init) and
 729 # $(vmlinux-main). Most are built-in.o files from top-level directories
 730 # in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
 731 # Ordering when linking is important, and $(vmlinux-init) must be first.
 732 #
 733 # vmlinux
 734 #   ^
 735 #   |
 736 #   +-< $(vmlinux-init)
 737 #   |   +--< init/version.o + more
 738 #   |
 739 #   +--< $(vmlinux-main)
 740 #   |    +--< driver/built-in.o mm/built-in.o + more
 741 #   |
 742 #   +-< kallsyms.o (see description in CONFIG_KALLSYMS section)
 743 #
 744 # vmlinux version (uname -v) cannot be updated during normal
 745 # descending-into-subdirs phase since we do not yet know if we need to
 746 # update vmlinux.
 747 # Therefore this step is delayed until just before final link of vmlinux -
 748 # except in the kallsyms case where it is done just before adding the
 749 # symbols to the kernel.
 750 #
 751 # System.map is generated to document addresses of all kernel symbols
 752
 753 vmlinux-init := $(head-y) $(init-y)
 754 vmlinux-main := $(core-y) $(libs-y) $(drivers-y) $(net-y)
 755 vmlinux-all  := $(vmlinux-init) $(vmlinux-main)
 756 vmlinux-lds  := arch/$(SRCARCH)/kernel/vmlinux.lds
 757 export KBUILD_VMLINUX_OBJS := $(vmlinux-all)
 758
 759 # Rule to link vmlinux - also used during CONFIG_KALLSYMS
 760 # May be overridden by arch/$(ARCH)/Makefile
 761 quiet_cmd_vmlinux__ ?= LD      $@
 762       cmd_vmlinux__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) -o $@ \
 763       -T $(vmlinux-lds) $(vmlinux-init)                          \
 764       --start-group $(vmlinux-main) --end-group                  \
 765       $(filter-out $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o FORCE ,$^)
 766
 767 # Generate new vmlinux version
 768 quiet_cmd_vmlinux_version = GEN     .version
 769       cmd_vmlinux_version = set -e;                     \
 770         if [ ! -r .version ]; then                      \
 771           rm -f .version;                               \
 772           echo 1 >.version;                             \
 773         else                                            \
 774           mv .version .old_version;                     \
 775           expr 0$$(cat .old_version) + 1 >.version;     \
 776         fi;                                             \
 777         $(MAKE) $(build)=init
 778
 779 # Generate System.map
 780 quiet_cmd_sysmap = SYSMAP
 781       cmd_sysmap = $(CONFIG_SHELL) $(srctree)/scripts/mksysmap
 782
 783 # Link of vmlinux
 784 # If CONFIG_KALLSYMS is set .version is already updated
 785 # Generate System.map and verify that the content is consistent
 786 # Use + in front of the vmlinux_version rule to silent warning with make -j2
 787 # First command is ':' to allow us to use + in front of the rule
 788 define rule_vmlinux__
 789         :
 790         $(if $(CONFIG_KALLSYMS),,+$(call cmd,vmlinux_version))
 791
 792         $(call cmd,vmlinux__)
 793         $(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
 794
 795         $(Q)$(if $($(quiet)cmd_sysmap),                                      \
 796           echo '  $($(quiet)cmd_sysmap)  System.map' &&)                     \
 797         $(cmd_sysmap) $@ System.map;                                         \
 798         if [ $$? -ne 0 ]; then                                               \
 799                 rm -f $@;                                                    \
 800                 /bin/false;                                                  \
 801         fi;
 802         $(verify_kallsyms)
 803 endef
 804
 805
 806 ifdef CONFIG_KALLSYMS
 807 # Generate section listing all symbols and add it into vmlinux $(kallsyms.o)
 808 # It's a three stage process:
 809 # o .tmp_vmlinux1 has all symbols and sections, but __kallsyms is
 810 #   empty
 811 #   Running kallsyms on that gives us .tmp_kallsyms1.o with
 812 #   the right size - vmlinux version (uname -v) is updated during this step
 813 # o .tmp_vmlinux2 now has a __kallsyms section of the right size,
 814 #   but due to the added section, some addresses have shifted.
 815 #   From here, we generate a correct .tmp_kallsyms2.o
 816 # o The correct .tmp_kallsyms2.o is linked into the final vmlinux.
 817 # o Verify that the System.map from vmlinux matches the map from
 818 #   .tmp_vmlinux2, just in case we did not generate kallsyms correctly.
 819 # o If 'make KALLSYMS_EXTRA_PASS=1" was used, do an extra pass using
 820 #   .tmp_vmlinux3 and .tmp_kallsyms3.o.  This is only meant as a
 821 #   temporary bypass to allow the kernel to be built while the
 822 #   maintainers work out what went wrong with kallsyms.
 823
 824 last_kallsyms := 2
 825
 826 ifdef KALLSYMS_EXTRA_PASS
 827 ifneq ($(KALLSYMS_EXTRA_PASS),0)
 828 last_kallsyms := 3
 829 endif
 830 endif
 831
 832 kallsyms.o := .tmp_kallsyms$(last_kallsyms).o
 833
 834 define verify_kallsyms
 835         $(Q)$(if $($(quiet)cmd_sysmap),                                      \
 836           echo '  $($(quiet)cmd_sysmap)  .tmp_System.map' &&)                \
 837           $(cmd_sysmap) .tmp_vmlinux$(last_kallsyms) .tmp_System.map
 838         $(Q)cmp -s System.map .tmp_System.map ||                             \
 839                 (echo Inconsistent kallsyms data;                            \
 840                  echo This is a bug - please report about it;                \
 841                  echo Try "make KALLSYMS_EXTRA_PASS=1" as a workaround;      \
 842                  rm .tmp_kallsyms* ; /bin/false )
 843 endef
 844
 845 # Update vmlinux version before link
 846 # Use + in front of this rule to silent warning about make -j1
 847 # First command is ':' to allow us to use + in front of this rule
 848 cmd_ksym_ld = $(cmd_vmlinux__)
 849 define rule_ksym_ld
 850         :
 851         +$(call cmd,vmlinux_version)
 852         $(call cmd,vmlinux__)
 853         $(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
 854 endef
 855
 856 # Generate .S file with all kernel symbols
 857 quiet_cmd_kallsyms = KSYM    $@
 858       cmd_kallsyms = $(NM) -n $< | $(KALLSYMS) \
 859                      $(if $(CONFIG_KALLSYMS_ALL),--all-symbols) > $@
 860
 861 .tmp_kallsyms1.o .tmp_kallsyms2.o .tmp_kallsyms3.o: %.o: %.S scripts FORCE
 862         $(call if_changed_dep,as_o_S)
 863
 864 .tmp_kallsyms%.S: .tmp_vmlinux% $(KALLSYMS)
 865         $(call cmd,kallsyms)
 866
 867 # .tmp_vmlinux1 must be complete except kallsyms, so update vmlinux version
 868 .tmp_vmlinux1: $(vmlinux-lds) $(vmlinux-all) FORCE
 869         $(call if_changed_rule,ksym_ld)
 870
 871 .tmp_vmlinux2: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms1.o FORCE
 872         $(call if_changed,vmlinux__)
 873
 874 .tmp_vmlinux3: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms2.o FORCE
 875         $(call if_changed,vmlinux__)
 876
 877 # Needs to visit scripts/ before $(KALLSYMS) can be used.
 878 $(KALLSYMS): scripts ;
 879
 880 # Generate some data for debugging strange kallsyms problems
 881 debug_kallsyms: .tmp_map$(last_kallsyms)
 882
 883 .tmp_map%: .tmp_vmlinux% FORCE
 884         ($(OBJDUMP) -h $< | $(AWK) '/^ +[0-9]/{print $$4 " 0 " $$2}'; $(NM) $<) | sort > $@
 885
 886 .tmp_map3: .tmp_map2
 887
 888 .tmp_map2: .tmp_map1
 889
 890 endif # ifdef CONFIG_KALLSYMS
 891
 892 # Do modpost on a prelinked vmlinux. The finally linked vmlinux has
 893 # relevant sections renamed as per the linker script.
 894 quiet_cmd_vmlinux-modpost = LD      $@
 895       cmd_vmlinux-modpost = $(LD) $(LDFLAGS) -r -o $@                          \
 896          $(vmlinux-init) --start-group $(vmlinux-main) --end-group             \
 897          $(filter-out $(vmlinux-init) $(vmlinux-main) FORCE ,$^)
 898 define rule_vmlinux-modpost
 899         :
 900         +$(call cmd,vmlinux-modpost)
 901         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost $@
 902         $(Q)echo 'cmd_$@ := $(cmd_vmlinux-modpost)' > $(dot-target).cmd
 903 endef
 904
 905 # vmlinux image - including updated kernel symbols
 906 vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o $(kallsyms.o) FORCE
 907 ifdef CONFIG_HEADERS_CHECK
 908         $(Q)$(MAKE) -f $(srctree)/Makefile headers_check
 909 endif
 910 ifdef CONFIG_SAMPLES
 911         $(Q)$(MAKE) $(build)=samples
 912 endif
 913 ifdef CONFIG_BUILD_DOCSRC
 914         $(Q)$(MAKE) $(build)=Documentation
 915 endif
 916         $(call vmlinux-modpost)
 917         $(call if_changed_rule,vmlinux__)
 918         $(Q)rm -f .old_version
 919
 920 # build vmlinux.o first to catch section mismatch errors early
 921 ifdef CONFIG_KALLSYMS
 922 .tmp_vmlinux1: vmlinux.o
 923 endif
 924
 925 modpost-init := $(filter-out init/built-in.o, $(vmlinux-init))
 926 vmlinux.o: $(modpost-init) $(vmlinux-main) FORCE
 927         $(call if_changed_rule,vmlinux-modpost)
 928
 929 # The actual objects are generated when descending,
 930 # make sure no implicit rule kicks in
 931 $(sort $(vmlinux-init) $(vmlinux-main)) $(vmlinux-lds): $(vmlinux-dirs) ;
 932
 933 # Handle descending into subdirectories listed in $(vmlinux-dirs)
 934 # Preset locale variables to speed up the build process. Limit locale
 935 # tweaks to this spot to avoid wrong language settings when running
 936 # make menuconfig etc.
 937 # Error messages still appears in the original language
 938
 939 PHONY += $(vmlinux-dirs)
 940 $(vmlinux-dirs): prepare scripts
 941         $(Q)$(MAKE) $(build)=$@
 942
 943 # Store (new) KERNELRELASE string in include/config/kernel.release
 944 include/config/kernel.release: include/config/auto.conf FORCE
 945         $(Q)rm -f $@
 946         $(Q)echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))" > $@
 947
 948
 949 # Things we need to do before we recursively start building the kernel
 950 # or the modules are listed in "prepare".
 951 # A multi level approach is used. prepareN is processed before prepareN-1.
 952 # archprepare is used in arch Makefiles and when processed asm symlink,
 953 # version.h and scripts_basic is processed / created.
 954
 955 # Listed in dependency order
 956 PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3
 957
 958 # prepare3 is used to check if we are building in a separate output directory,
 959 # and if so do:
 960 # 1) Check that make has not been executed in the kernel src $(srctree)
 961 prepare3: include/config/kernel.release
 962 ifneq ($(KBUILD_SRC),)
 963         @$(kecho) '  Using $(srctree) as source for kernel'
 964         $(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \
 965                 echo "  $(srctree) is not clean, please run 'make mrproper'";\
 966                 echo "  in the '$(srctree)' directory.";\
 967                 /bin/false; \
 968         fi;
 969 endif
 970
 971 # prepare2 creates a makefile if using a separate output directory
 972 prepare2: prepare3 outputmakefile asm-generic
 973
 974 prepare1: prepare2 include/linux/version.h include/generated/utsrelease.h \
 975                    include/config/auto.conf
 976         $(cmd_crmodverdir)
 977
 978 archprepare: archheaders prepare1 scripts_basic
 979
 980 prepare0: archprepare FORCE
 981         $(Q)$(MAKE) $(build)=.
 982
 983 # All the preparing..
 984 prepare: prepare0
 985
 986 # Generate some files
 987 # ---------------------------------------------------------------------------
 988
 989 # KERNELRELEASE can change from a few different places, meaning version.h
 990 # needs to be updated, so this check is forced on all builds
 991
 992 uts_len := 64
 993 define filechk_utsrelease.h
 994         if [ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt $(uts_len) ]; then \
 995           echo '"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2;    \
 996           exit 1;                                                         \
 997         fi;                                                               \
 998         (echo \#define UTS_RELEASE \"$(KERNELRELEASE)\";)
 999 endef
1000
1001 define filechk_version.h
1002         (echo \#define LINUX_VERSION_CODE $(shell                             \
1003         expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 0$(SUBLEVEL));    \
1004         echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))';)
1005 endef
1006
1007 include/linux/version.h: $(srctree)/Makefile FORCE
1008         $(call filechk,version.h)
1009
1010 include/generated/utsrelease.h: include/config/kernel.release FORCE
1011         $(call filechk,utsrelease.h)
1012
1013 PHONY += headerdep
1014 headerdep:
1015         $(Q)find $(srctree)/include/ -name '*.h' | xargs --max-args 1 \
1016         $(srctree)/scripts/headerdep.pl -I$(srctree)/include
1017
1018 # ---------------------------------------------------------------------------
1019
1020 PHONY += depend dep
1021 depend dep:
1022         @echo '*** Warning: make $@ is unnecessary now.'
1023
1024 # ---------------------------------------------------------------------------
1025 # Firmware install
1026 INSTALL_FW_PATH=$(INSTALL_MOD_PATH)/lib/firmware
1027 export INSTALL_FW_PATH
1028
1029 PHONY += firmware_install
1030 firmware_install: FORCE
1031         @mkdir -p $(objtree)/firmware
1032         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_install
1033
1034 # ---------------------------------------------------------------------------
1035 # Kernel headers
1036
1037 #Default location for installed headers
1038 export INSTALL_HDR_PATH = $(objtree)/usr
1039
1040 hdr-inst := -rR -f $(srctree)/scripts/Makefile.headersinst obj
1041
1042 # If we do an all arch process set dst to asm-$(hdr-arch)
1043 hdr-dst = $(if $(KBUILD_HEADERS), dst=include/asm-$(hdr-arch), dst=include/asm)
1044
1045 PHONY += archheaders
1046 archheaders:
1047
1048 PHONY += __headers
1049 __headers: include/linux/version.h scripts_basic asm-generic archheaders FORCE
1050         $(Q)$(MAKE) $(build)=scripts build_unifdef
1051
1052 PHONY += headers_install_all
1053 headers_install_all:
1054         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh install
1055
1056 PHONY += headers_install
1057 headers_install: __headers
1058         $(if $(wildcard $(srctree)/arch/$(hdr-arch)/include/asm/Kbuild),, \
1059         $(error Headers not exportable for the $(SRCARCH) architecture))
1060         $(Q)$(MAKE) $(hdr-inst)=include
1061         $(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/asm $(hdr-dst)
1062
1063 PHONY += headers_check_all
1064 headers_check_all: headers_install_all
1065         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh check
1066
1067 PHONY += headers_check
1068 headers_check: headers_install
1069         $(Q)$(MAKE) $(hdr-inst)=include HDRCHECK=1
1070         $(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/asm $(hdr-dst) HDRCHECK=1
1071
1072 # ---------------------------------------------------------------------------
1073 # Modules
1074
1075 ifdef CONFIG_MODULES
1076
1077 # By default, build modules as well
1078
1079 all: modules
1080
1081 #       Build modules
1082 #
1083 #       A module can be listed more than once in obj-m resulting in
1084 #       duplicate lines in modules.order files.  Those are removed
1085 #       using awk while concatenating to the final file.
1086
1087 PHONY += modules
1088 modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin
1089         $(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order
1090         @$(kecho) '  Building modules, stage 2.';
1091         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1092         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modbuild
1093
1094 modules.builtin: $(vmlinux-dirs:%=%/modules.builtin)
1095         $(Q)$(AWK) '!x[$$0]++' $^ > $(objtree)/modules.builtin
1096
1097 %/modules.builtin: include/config/auto.conf
1098         $(Q)$(MAKE) $(modbuiltin)=$*
1099
1100
1101 # Target to prepare building external modules
1102 PHONY += modules_prepare
1103 modules_prepare: prepare scripts
1104
1105 # Target to install modules
1106 PHONY += modules_install
1107 modules_install: _modinst_ _modinst_post
1108
1109 PHONY += _modinst_
1110 _modinst_:
1111         @rm -rf $(MODLIB)/kernel
1112         @rm -f $(MODLIB)/source
1113         @mkdir -p $(MODLIB)/kernel
1114         @ln -s $(srctree) $(MODLIB)/source
1115         @if [ ! $(objtree) -ef  $(MODLIB)/build ]; then \
1116                 rm -f $(MODLIB)/build ; \
1117                 ln -s $(objtree) $(MODLIB)/build ; \
1118         fi
1119         @cp -f $(objtree)/modules.order $(MODLIB)/
1120         @cp -f $(objtree)/modules.builtin $(MODLIB)/
1121         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
1122
1123 # This depmod is only for convenience to give the initial
1124 # boot a modules.dep even before / is mounted read-write.  However the
1125 # boot script depmod is the master version.
1126 PHONY += _modinst_post
1127 _modinst_post: _modinst_
1128         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modinst
1129         $(call cmd,depmod)
1130
1131 else # CONFIG_MODULES
1132
1133 # Modules not configured
1134 # ---------------------------------------------------------------------------
1135
1136 modules modules_install: FORCE
1137         @echo
1138         @echo "The present kernel configuration has modules disabled."
1139         @echo "Type 'make config' and enable loadable module support."
1140         @echo "Then build a kernel with module support enabled."
1141         @echo
1142         @exit 1
1143
1144 endif # CONFIG_MODULES
1145
1146 ###
1147 # Cleaning is done on three levels.
1148 # make clean     Delete most generated files
1149 #                Leave enough to build external modules
1150 # make mrproper  Delete the current configuration, and all generated files
1151 # make distclean Remove editor backup files, patch leftover files and the like
1152
1153 # Directories & files removed with 'make clean'
1154 CLEAN_DIRS  += $(MODVERDIR)
1155 CLEAN_FILES +=  vmlinux System.map \
1156                 .tmp_kallsyms* .tmp_version .tmp_vmlinux* .tmp_System.map
1157
1158 # Directories & files removed with 'make mrproper'
1159 MRPROPER_DIRS  += include/config usr/include include/generated          \
1160                   arch/*/include/generated
1161 MRPROPER_FILES += .config .config.old .version .old_version             \
1162                   include/linux/version.h                               \
1163                   Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
1164
1165 # clean - Delete most, but leave enough to build external modules
1166 #
1167 clean: rm-dirs  := $(CLEAN_DIRS)
1168 clean: rm-files := $(CLEAN_FILES)
1169 clean-dirs      := $(addprefix _clean_, . $(vmlinux-alldirs) Documentation samples)
1170
1171 PHONY += $(clean-dirs) clean archclean
1172 $(clean-dirs):
1173         $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
1174
1175 clean: archclean
1176
1177 # mrproper - Delete all generated files, including .config
1178 #
1179 mrproper: rm-dirs  := $(wildcard $(MRPROPER_DIRS))
1180 mrproper: rm-files := $(wildcard $(MRPROPER_FILES))
1181 mrproper-dirs      := $(addprefix _mrproper_,Documentation/DocBook scripts)
1182
1183 PHONY += $(mrproper-dirs) mrproper archmrproper
1184 $(mrproper-dirs):
1185         $(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@)
1186
1187 mrproper: clean archmrproper $(mrproper-dirs)
1188         $(call cmd,rmdirs)
1189         $(call cmd,rmfiles)
1190
1191 # distclean
1192 #
1193 PHONY += distclean
1194
1195 distclean: mrproper
1196         @find $(srctree) $(RCS_FIND_IGNORE) \
1197                 \( -name '*.orig' -o -name '*.rej' -o -name '*~' \
1198                 -o -name '*.bak' -o -name '#*#' -o -name '.*.orig' \
1199                 -o -name '.*.rej' \
1200                 -o -name '*%' -o -name '.*.cmd' -o -name 'core' \) \
1201                 -type f -print | xargs rm -f
1202
1203
1204 # Packaging of the kernel to various formats
1205 # ---------------------------------------------------------------------------
1206 # rpm target kept for backward compatibility
1207 package-dir     := $(srctree)/scripts/package
1208
1209 %src-pkg: FORCE
1210         $(Q)$(MAKE) $(build)=$(package-dir) $@
1211 %pkg: include/config/kernel.release FORCE
1212         $(Q)$(MAKE) $(build)=$(package-dir) $@
1213 rpm: include/config/kernel.release FORCE
1214         $(Q)$(MAKE) $(build)=$(package-dir) $@
1215
1216
1217 # Brief documentation of the typical targets used
1218 # ---------------------------------------------------------------------------
1219
1220 boards := $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*_defconfig)
1221 boards := $(notdir $(boards))
1222 board-dirs := $(dir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*/*_defconfig))
1223 board-dirs := $(sort $(notdir $(board-dirs:/=)))
1224
1225 help:
1226         @echo  'Cleaning targets:'
1227         @echo  '  clean           - Remove most generated files but keep the config and'
1228         @echo  '                    enough build support to build external modules'
1229         @echo  '  mrproper        - Remove all generated files + config + various backup files'
1230         @echo  '  distclean       - mrproper + remove editor backup and patch files'
1231         @echo  ''
1232         @echo  'Configuration targets:'
1233         @$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
1234         @echo  ''
1235         @echo  'Other generic targets:'
1236         @echo  '  all             - Build all targets marked with [*]'
1237         @echo  '* vmlinux         - Build the bare kernel'
1238         @echo  '* modules         - Build all modules'
1239         @echo  '  modules_install - Install all modules to INSTALL_MOD_PATH (default: /)'
1240         @echo  '  firmware_install- Install all firmware to INSTALL_FW_PATH'
1241         @echo  '                    (default: $$(INSTALL_MOD_PATH)/lib/firmware)'
1242         @echo  '  dir/            - Build all files in dir and below'
1243         @echo  '  dir/file.[oisS] - Build specified target only'
1244         @echo  '  dir/file.lst    - Build specified mixed source/assembly target only'
1245         @echo  '                    (requires a recent binutils and recent build (System.map))'
1246         @echo  '  dir/file.ko     - Build module including final link'
1247         @echo  '  modules_prepare - Set up for building external modules'
1248         @echo  '  tags/TAGS       - Generate tags file for editors'
1249         @echo  '  cscope          - Generate cscope index'
1250         @echo  '  gtags           - Generate GNU GLOBAL index'
1251         @echo  '  kernelrelease   - Output the release version string'
1252         @echo  '  kernelversion   - Output the version stored in Makefile'
1253         @echo  '  headers_install - Install sanitised kernel headers to INSTALL_HDR_PATH'; \
1254          echo  '                    (default: $(INSTALL_HDR_PATH))'; \
1255          echo  ''
1256         @echo  'Static analysers'
1257         @echo  '  checkstack      - Generate a list of stack hogs'
1258         @echo  '  namespacecheck  - Name space analysis on compiled kernel'
1259         @echo  '  versioncheck    - Sanity check on version.h usage'
1260         @echo  '  includecheck    - Check for duplicate included header files'
1261         @echo  '  export_report   - List the usages of all exported symbols'
1262         @echo  '  headers_check   - Sanity check on exported headers'
1263         @echo  '  headerdep       - Detect inclusion cycles in headers'
1264         @$(MAKE) -f $(srctree)/scripts/Makefile.help checker-help
1265         @echo  ''
1266         @echo  'Kernel packaging:'
1267         @$(MAKE) $(build)=$(package-dir) help
1268         @echo  ''
1269         @echo  'Documentation targets:'
1270         @$(MAKE) -f $(srctree)/Documentation/DocBook/Makefile dochelp
1271         @echo  ''
1272         @echo  'Architecture specific targets ($(SRCARCH)):'
1273         @$(if $(archhelp),$(archhelp),\
1274                 echo '  No architecture specific help defined for $(SRCARCH)')
1275         @echo  ''
1276         @$(if $(boards), \
1277                 $(foreach b, $(boards), \
1278                 printf "  %-24s - Build for %s\\n" $(b) $(subst _defconfig,,$(b));) \
1279                 echo '')
1280         @$(if $(board-dirs), \
1281                 $(foreach b, $(board-dirs), \
1282                 printf "  %-16s - Show %s-specific targets\\n" help-$(b) $(b);) \
1283                 printf "  %-16s - Show all of the above\\n" help-boards; \
1284                 echo '')
1285
1286         @echo  '  make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
1287         @echo  '  make V=2   [targets] 2 => give reason for rebuild of target'
1288         @echo  '  make O=dir [targets] Locate all output files in "dir", including .config'
1289         @echo  '  make C=1   [targets] Check all c source with $$CHECK (sparse by default)'
1290         @echo  '  make C=2   [targets] Force check of all c source with $$CHECK'
1291         @echo  '  make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections'
1292         @echo  '  make W=n   [targets] Enable extra gcc checks, n=1,2,3 where'
1293         @echo  '                1: warnings which may be relevant and do not occur too often'
1294         @echo  '                2: warnings which occur quite often but may still be relevant'
1295         @echo  '                3: more obscure warnings, can most likely be ignored'
1296         @echo  '                Multiple levels can be combined with W=12 or W=123'
1297         @echo  ''
1298         @echo  'Execute "make" or "make all" to build all targets marked with [*] '
1299         @echo  'For further info see the ./README file'
1300
1301
1302 help-board-dirs := $(addprefix help-,$(board-dirs))
1303
1304 help-boards: $(help-board-dirs)
1305
1306 boards-per-dir = $(notdir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/$*/*_defconfig))
1307
1308 $(help-board-dirs): help-%:
1309         @echo  'Architecture specific targets ($(SRCARCH) $*):'
1310         @$(if $(boards-per-dir), \
1311                 $(foreach b, $(boards-per-dir), \
1312                 printf "  %-24s - Build for %s\\n" $*/$(b) $(subst _defconfig,,$(b));) \
1313                 echo '')
1314
1315
1316 # Documentation targets
1317 # ---------------------------------------------------------------------------
1318 %docs: scripts_basic FORCE
1319         $(Q)$(MAKE) $(build)=scripts build_docproc
1320         $(Q)$(MAKE) $(build)=Documentation/DocBook $@
1321
1322 else # KBUILD_EXTMOD
1323
1324 ###
1325 # External module support.
1326 # When building external modules the kernel used as basis is considered
1327 # read-only, and no consistency checks are made and the make
1328 # system is not used on the basis kernel. If updates are required
1329 # in the basis kernel ordinary make commands (without M=...) must
1330 # be used.
1331 #
1332 # The following are the only valid targets when building external
1333 # modules.
1334 # make M=dir clean     Delete all automatically generated files
1335 # make M=dir modules   Make all modules in specified dir
1336 # make M=dir           Same as 'make M=dir modules'
1337 # make M=dir modules_install
1338 #                      Install the modules built in the module directory
1339 #                      Assumes install directory is already created
1340
1341 # We are always building modules
1342 KBUILD_MODULES := 1
1343 PHONY += crmodverdir
1344 crmodverdir:
1345         $(cmd_crmodverdir)
1346
1347 PHONY += $(objtree)/Module.symvers
1348 $(objtree)/Module.symvers:
1349         @test -e $(objtree)/Module.symvers || ( \
1350         echo; \
1351         echo "  WARNING: Symbol version dump $(objtree)/Module.symvers"; \
1352         echo "           is missing; modules will have no dependencies and modversions."; \
1353         echo )
1354
1355 module-dirs := $(addprefix _module_,$(KBUILD_EXTMOD))
1356 PHONY += $(module-dirs) modules
1357 $(module-dirs): crmodverdir $(objtree)/Module.symvers
1358         $(Q)$(MAKE) $(build)=$(patsubst _module_%,%,$@)
1359
1360 modules: $(module-dirs)
1361         @$(kecho) '  Building modules, stage 2.';
1362         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1363
1364 PHONY += modules_install
1365 modules_install: _emodinst_ _emodinst_post
1366
1367 install-dir := $(if $(INSTALL_MOD_DIR),$(INSTALL_MOD_DIR),extra)
1368 PHONY += _emodinst_
1369 _emodinst_:
1370         $(Q)mkdir -p $(MODLIB)/$(install-dir)
1371         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
1372
1373 PHONY += _emodinst_post
1374 _emodinst_post: _emodinst_
1375         $(call cmd,depmod)
1376
1377 clean-dirs := $(addprefix _clean_,$(KBUILD_EXTMOD))
1378
1379 PHONY += $(clean-dirs) clean
1380 $(clean-dirs):
1381         $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
1382
1383 clean:  rm-dirs := $(MODVERDIR)
1384 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
1385
1386 help:
1387         @echo  '  Building external modules.'
1388         @echo  '  Syntax: make -C path/to/kernel/src M=$$PWD target'
1389         @echo  ''
1390         @echo  '  modules         - default target, build the module(s)'
1391         @echo  '  modules_install - install the module'
1392         @echo  '  clean           - remove generated files in module directory only'
1393         @echo  ''
1394
1395 # Dummies...
1396 PHONY += prepare scripts
1397 prepare: ;
1398 scripts: ;
1399 endif # KBUILD_EXTMOD
1400
1401 clean: $(clean-dirs)
1402         $(call cmd,rmdirs)
1403         $(call cmd,rmfiles)
1404         @find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
1405                 \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
1406                 -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
1407                 -o -name '*.symtypes' -o -name 'modules.order' \
1408                 -o -name modules.builtin -o -name '.tmp_*.o.*' \
1409                 -o -name '*.gcno' \) -type f -print | xargs rm -f
1410
1411 # Generate tags for editors
1412 # ---------------------------------------------------------------------------
1413 quiet_cmd_tags = GEN     $@
1414       cmd_tags = $(CONFIG_SHELL) $(srctree)/scripts/tags.sh $@
1415
1416 tags TAGS cscope gtags: FORCE
1417         $(call cmd,tags)
1418
1419 # Scripts to check various things for consistency
1420 # ---------------------------------------------------------------------------
1421
1422 PHONY += includecheck versioncheck coccicheck namespacecheck export_report
1423
1424 includecheck:
1425         find $(srctree)/* $(RCS_FIND_IGNORE) \
1426                 -name '*.[hcS]' -type f -print | sort \
1427                 | xargs $(PERL) -w $(srctree)/scripts/checkincludes.pl
1428
1429 versioncheck:
1430         find $(srctree)/* $(RCS_FIND_IGNORE) \
1431                 -name '*.[hcS]' -type f -print | sort \
1432                 | xargs $(PERL) -w $(srctree)/scripts/checkversion.pl
1433
1434 coccicheck:
1435         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
1436
1437 namespacecheck:
1438         $(PERL) $(srctree)/scripts/namespace.pl
1439
1440 export_report:
1441         $(PERL) $(srctree)/scripts/export_report.pl
1442
1443 endif #ifeq ($(config-targets),1)
1444 endif #ifeq ($(mixed-targets),1)
1445
1446 PHONY += checkstack kernelrelease kernelversion
1447
1448 # UML needs a little special treatment here.  It wants to use the host
1449 # toolchain, so needs $(SUBARCH) passed to checkstack.pl.  Everyone
1450 # else wants $(ARCH), including people doing cross-builds, which means
1451 # that $(SUBARCH) doesn't work here.
1452 ifeq ($(ARCH), um)
1453 CHECKSTACK_ARCH := $(SUBARCH)
1454 else
1455 CHECKSTACK_ARCH := $(ARCH)
1456 endif
1457 checkstack:
1458         $(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
1459         $(PERL) $(src)/scripts/checkstack.pl $(CHECKSTACK_ARCH)
1460
1461 kernelrelease:
1462         @echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
1463
1464 kernelversion:
1465         @echo $(KERNELVERSION)
1466
1467 # Single targets
1468 # ---------------------------------------------------------------------------
1469 # Single targets are compatible with:
1470 # - build with mixed source and output
1471 # - build with separate output dir 'make O=...'
1472 # - external modules
1473 #
1474 #  target-dir => where to store outputfile
1475 #  build-dir  => directory in kernel source tree to use
1476
1477 ifeq ($(KBUILD_EXTMOD),)
1478         build-dir  = $(patsubst %/,%,$(dir $@))
1479         target-dir = $(dir $@)
1480 else
1481         zap-slash=$(filter-out .,$(patsubst %/,%,$(dir $@)))
1482         build-dir  = $(KBUILD_EXTMOD)$(if $(zap-slash),/$(zap-slash))
1483         target-dir = $(if $(KBUILD_EXTMOD),$(dir $<),$(dir $@))
1484 endif
1485
1486 %.s: %.c prepare scripts FORCE
1487         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1488 %.i: %.c prepare scripts FORCE
1489         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1490 %.o: %.c prepare scripts FORCE
1491         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1492 %.lst: %.c prepare scripts FORCE
1493         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1494 %.s: %.S prepare scripts FORCE
1495         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1496 %.o: %.S prepare scripts FORCE
1497         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1498 %.symtypes: %.c prepare scripts FORCE
1499         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1500
1501 # Modules
1502 /: prepare scripts FORCE
1503         $(cmd_crmodverdir)
1504         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) \
1505         $(build)=$(build-dir)
1506 %/: prepare scripts FORCE
1507         $(cmd_crmodverdir)
1508         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) \
1509         $(build)=$(build-dir)
1510 %.ko: prepare scripts FORCE
1511         $(cmd_crmodverdir)
1512         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1)   \
1513         $(build)=$(build-dir) $(@:.ko=.o)
1514         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1515
1516 # FIXME Should go into a make.lib or something
1517 # ===========================================================================
1518
1519 quiet_cmd_rmdirs = $(if $(wildcard $(rm-dirs)),CLEAN   $(wildcard $(rm-dirs)))
1520       cmd_rmdirs = rm -rf $(rm-dirs)
1521
1522 quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN   $(wildcard $(rm-files)))
1523       cmd_rmfiles = rm -f $(rm-files)
1524
1525 # Run depmod only if we have System.map and depmod is executable
1526 quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)
1527       cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \
1528                    $(KERNELRELEASE)
1529
1530 # Create temporary dir for module support files
1531 # clean it up only when building all modules
1532 cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
1533                   $(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)
1534
1535 a_flags = -Wp,-MD,$(depfile) $(KBUILD_AFLAGS) $(AFLAGS_KERNEL) \
1536           $(KBUILD_AFLAGS_KERNEL)                              \
1537           $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(KBUILD_CPPFLAGS) \
1538           $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)
1539
1540 quiet_cmd_as_o_S = AS      $@
1541 cmd_as_o_S       = $(CC) $(a_flags) -c -o $@ $<
1542
1543 # read all saved command lines
1544
1545 targets := $(wildcard $(sort $(targets)))
1546 cmd_files := $(wildcard .*.cmd $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
1547
1548 ifneq ($(cmd_files),)
1549   $(cmd_files): ;       # Do not try to update included dependency files
1550   include $(cmd_files)
1551 endif
1552
1553 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=dir
1554 # Usage:
1555 # $(Q)$(MAKE) $(clean)=dir
1556 clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj
1557
1558 endif   # skip-makefile
1559
1560 PHONY += FORCE
1561 FORCE:
1562
1563 # Declare the contents of the .PHONY variable as phony.  We keep that
1564 # information in a variable so we can use it in if_changed and friends.
1565 .PHONY: $(PHONY)