Makefile

   1 VERSION = 3
   2 PATCHLEVEL = 2
   3 SUBLEVEL = 0
   4 EXTRAVERSION = -rc4
   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  := $(SRCARCH)
 233
 234 ifeq ($(ARCH),m68knommu)
 235        hdr-arch  := m68k
 236 endif
 237
 238 KCONFIG_CONFIG  ?= .config
 239 export KCONFIG_CONFIG
 240
 241 # SHELL used by kbuild
 242 CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
 243           else if [ -x /bin/bash ]; then echo /bin/bash; \
 244           else echo sh; fi ; fi)
 245
 246 HOSTCC       = gcc
 247 HOSTCXX      = g++
 248 HOSTCFLAGS   = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer
 249 HOSTCXXFLAGS = -O2
 250
 251 # Decide whether to build built-in, modular, or both.
 252 # Normally, just do built-in.
 253
 254 KBUILD_MODULES :=
 255 KBUILD_BUILTIN := 1
 256
 257 #       If we have only "make modules", don't compile built-in objects.
 258 #       When we're building modules with modversions, we need to consider
 259 #       the built-in objects during the descend as well, in order to
 260 #       make sure the checksums are up to date before we record them.
 261
 262 ifeq ($(MAKECMDGOALS),modules)
 263   KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1)
 264 endif
 265
 266 #       If we have "make <whatever> modules", compile modules
 267 #       in addition to whatever we do anyway.
 268 #       Just "make" or "make all" shall build modules as well
 269
 270 ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
 271   KBUILD_MODULES := 1
 272 endif
 273
 274 ifeq ($(MAKECMDGOALS),)
 275   KBUILD_MODULES := 1
 276 endif
 277
 278 export KBUILD_MODULES KBUILD_BUILTIN
 279 export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD
 280
 281 # Beautify output
 282 # ---------------------------------------------------------------------------
 283 #
 284 # Normally, we echo the whole command before executing it. By making
 285 # that echo $($(quiet)$(cmd)), we now have the possibility to set
 286 # $(quiet) to choose other forms of output instead, e.g.
 287 #
 288 #         quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
 289 #         cmd_cc_o_c       = $(CC) $(c_flags) -c -o $@ $<
 290 #
 291 # If $(quiet) is empty, the whole command will be printed.
 292 # If it is set to "quiet_", only the short version will be printed.
 293 # If it is set to "silent_", nothing will be printed at all, since
 294 # the variable $(silent_cmd_cc_o_c) doesn't exist.
 295 #
 296 # A simple variant is to prefix commands with $(Q) - that's useful
 297 # for commands that shall be hidden in non-verbose mode.
 298 #
 299 #       $(Q)ln $@ :<
 300 #
 301 # If KBUILD_VERBOSE equals 0 then the above command will be hidden.
 302 # If KBUILD_VERBOSE equals 1 then the above command is displayed.
 303
 304 ifeq ($(KBUILD_VERBOSE),1)
 305   quiet =
 306   Q =
 307 else
 308   quiet=quiet_
 309   Q = @
 310 endif
 311
 312 # If the user is running make -s (silent mode), suppress echoing of
 313 # commands
 314
 315 ifneq ($(findstring s,$(MAKEFLAGS)),)
 316   quiet=silent_
 317 endif
 318
 319 export quiet Q KBUILD_VERBOSE
 320
 321
 322 # Look for make include files relative to root of kernel src
 323 MAKEFLAGS += --include-dir=$(srctree)
 324
 325 # We need some generic definitions (do not try to remake the file).
 326 $(srctree)/scripts/Kbuild.include: ;
 327 include $(srctree)/scripts/Kbuild.include
 328
 329 # Make variables (CC, etc...)
 330
 331 AS              = $(CROSS_COMPILE)as
 332 LD              = $(CROSS_COMPILE)ld
 333 CC              = $(CROSS_COMPILE)gcc
 334 CPP             = $(CC) -E
 335 AR              = $(CROSS_COMPILE)ar
 336 NM              = $(CROSS_COMPILE)nm
 337 STRIP           = $(CROSS_COMPILE)strip
 338 OBJCOPY         = $(CROSS_COMPILE)objcopy
 339 OBJDUMP         = $(CROSS_COMPILE)objdump
 340 AWK             = awk
 341 GENKSYMS        = scripts/genksyms/genksyms
 342 INSTALLKERNEL  := installkernel
 343 DEPMOD          = /sbin/depmod
 344 KALLSYMS        = scripts/kallsyms
 345 PERL            = perl
 346 CHECK           = sparse
 347
 348 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
 349                   -Wbitwise -Wno-return-void $(CF)
 350 CFLAGS_MODULE   =
 351 AFLAGS_MODULE   =
 352 LDFLAGS_MODULE  =
 353 CFLAGS_KERNEL   =
 354 AFLAGS_KERNEL   =
 355 CFLAGS_GCOV     = -fprofile-arcs -ftest-coverage
 356
 357
 358 # Use LINUXINCLUDE when you must reference the include/ directory.
 359 # Needed to be compatible with the O= option
 360 LINUXINCLUDE    := -I$(srctree)/arch/$(hdr-arch)/include \
 361                    -Iarch/$(hdr-arch)/include/generated -Iinclude \
 362                    $(if $(KBUILD_SRC), -I$(srctree)/include) \
 363                    -include $(srctree)/include/linux/kconfig.h
 364
 365 KBUILD_CPPFLAGS := -D__KERNEL__
 366
 367 KBUILD_CFLAGS   := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
 368                    -fno-strict-aliasing -fno-common \
 369                    -Werror-implicit-function-declaration \
 370                    -Wno-format-security \
 371                    -fno-delete-null-pointer-checks
 372 KBUILD_AFLAGS_KERNEL :=
 373 KBUILD_CFLAGS_KERNEL :=
 374 KBUILD_AFLAGS   := -D__ASSEMBLY__
 375 KBUILD_AFLAGS_MODULE  := -DMODULE
 376 KBUILD_CFLAGS_MODULE  := -DMODULE
 377 KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
 378
 379 # Read KERNELRELEASE from include/config/kernel.release (if it exists)
 380 KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
 381 KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
 382
 383 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
 384 export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 385 export CPP AR NM STRIP OBJCOPY OBJDUMP
 386 export MAKE AWK GENKSYMS INSTALLKERNEL PERL UTS_MACHINE
 387 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 388
 389 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
 390 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV
 391 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 392 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 393 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
 394 export KBUILD_ARFLAGS
 395
 396 # When compiling out-of-tree modules, put MODVERDIR in the module
 397 # tree rather than in the kernel tree. The kernel tree might
 398 # even be read-only.
 399 export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
 400
 401 # Files to ignore in find ... statements
 402
 403 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
 404 export RCS_TAR_IGNORE := --exclude SCCS --exclude BitKeeper --exclude .svn --exclude CVS --exclude .pc --exclude .hg --exclude .git
 405
 406 # ===========================================================================
 407 # Rules shared between *config targets and build targets
 408
 409 # Basic helpers built in scripts/
 410 PHONY += scripts_basic
 411 scripts_basic:
 412         $(Q)$(MAKE) $(build)=scripts/basic
 413         $(Q)rm -f .tmp_quiet_recordmcount
 414
 415 # To avoid any implicit rule to kick in, define an empty command.
 416 scripts/basic/%: scripts_basic ;
 417
 418 PHONY += outputmakefile
 419 # outputmakefile generates a Makefile in the output directory, if using a
 420 # separate output directory. This allows convenient use of make in the
 421 # output directory.
 422 outputmakefile:
 423 ifneq ($(KBUILD_SRC),)
 424         $(Q)ln -fsn $(srctree) source
 425         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile \
 426             $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)
 427 endif
 428
 429 # Support for using generic headers in asm-generic
 430 PHONY += asm-generic
 431 asm-generic:
 432         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \
 433                     obj=arch/$(SRCARCH)/include/generated/asm
 434
 435 # To make sure we do not include .config for any of the *config targets
 436 # catch them early, and hand them over to scripts/kconfig/Makefile
 437 # It is allowed to specify more targets when calling make, including
 438 # mixing *config targets and build targets.
 439 # For example 'make oldconfig all'.
 440 # Detect when mixed targets is specified, and make a second invocation
 441 # of make so .config is not included in this case either (for *config).
 442
 443 no-dot-config-targets := clean mrproper distclean \
 444                          cscope gtags TAGS tags help %docs check% coccicheck \
 445                          include/linux/version.h headers_% \
 446                          kernelversion %src-pkg
 447
 448 config-targets := 0
 449 mixed-targets  := 0
 450 dot-config     := 1
 451
 452 ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
 453         ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
 454                 dot-config := 0
 455         endif
 456 endif
 457
 458 ifeq ($(KBUILD_EXTMOD),)
 459         ifneq ($(filter config %config,$(MAKECMDGOALS)),)
 460                 config-targets := 1
 461                 ifneq ($(filter-out config %config,$(MAKECMDGOALS)),)
 462                         mixed-targets := 1
 463                 endif
 464         endif
 465 endif
 466
 467 ifeq ($(mixed-targets),1)
 468 # ===========================================================================
 469 # We're called with mixed targets (*config and build targets).
 470 # Handle them one by one.
 471
 472 %:: FORCE
 473         $(Q)$(MAKE) -C $(srctree) KBUILD_SRC= $@
 474
 475 else
 476 ifeq ($(config-targets),1)
 477 # ===========================================================================
 478 # *config targets only - make sure prerequisites are updated, and descend
 479 # in scripts/kconfig to make the *config target
 480
 481 # Read arch specific Makefile to set KBUILD_DEFCONFIG as needed.
 482 # KBUILD_DEFCONFIG may point out an alternative default configuration
 483 # used for 'make defconfig'
 484 include $(srctree)/arch/$(SRCARCH)/Makefile
 485 export KBUILD_DEFCONFIG KBUILD_KCONFIG
 486
 487 config: scripts_basic outputmakefile FORCE
 488         $(Q)mkdir -p include/linux include/config
 489         $(Q)$(MAKE) $(build)=scripts/kconfig $@
 490
 491 %config: scripts_basic outputmakefile FORCE
 492         $(Q)mkdir -p include/linux include/config
 493         $(Q)$(MAKE) $(build)=scripts/kconfig $@
 494
 495 else
 496 # ===========================================================================
 497 # Build targets only - this includes vmlinux, arch specific targets, clean
 498 # targets and others. In general all targets except *config targets.
 499
 500 ifeq ($(KBUILD_EXTMOD),)
 501 # Additional helpers built in scripts/
 502 # Carefully list dependencies so we do not try to build scripts twice
 503 # in parallel
 504 PHONY += scripts
 505 scripts: scripts_basic include/config/auto.conf include/config/tristate.conf
 506         $(Q)$(MAKE) $(build)=$(@)
 507
 508 # Objects we will link into vmlinux / subdirs we need to visit
 509 init-y          := init/
 510 drivers-y       := drivers/ sound/ firmware/
 511 net-y           := net/
 512 libs-y          := lib/
 513 core-y          := usr/
 514 endif # KBUILD_EXTMOD
 515
 516 ifeq ($(dot-config),1)
 517 # Read in config
 518 -include include/config/auto.conf
 519
 520 ifeq ($(KBUILD_EXTMOD),)
 521 # Read in dependencies to all Kconfig* files, make sure to run
 522 # oldconfig if changes are detected.
 523 -include include/config/auto.conf.cmd
 524
 525 # To avoid any implicit rule to kick in, define an empty command
 526 $(KCONFIG_CONFIG) include/config/auto.conf.cmd: ;
 527
 528 # If .config is newer than include/config/auto.conf, someone tinkered
 529 # with it and forgot to run make oldconfig.
 530 # if auto.conf.cmd is missing then we are probably in a cleaned tree so
 531 # we execute the config step to be sure to catch updated Kconfig files
 532 include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd
 533         $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig
 534 else
 535 # external modules needs include/generated/autoconf.h and include/config/auto.conf
 536 # but do not care if they are up-to-date. Use auto.conf to trigger the test
 537 PHONY += include/config/auto.conf
 538
 539 include/config/auto.conf:
 540         $(Q)test -e include/generated/autoconf.h -a -e $@ || (          \
 541         echo;                                                           \
 542         echo "  ERROR: Kernel configuration is invalid.";               \
 543         echo "         include/generated/autoconf.h or $@ are missing.";\
 544         echo "         Run 'make oldconfig && make prepare' on kernel src to fix it.";  \
 545         echo;                                                           \
 546         /bin/false)
 547
 548 endif # KBUILD_EXTMOD
 549
 550 else
 551 # Dummy target needed, because used as prerequisite
 552 include/config/auto.conf: ;
 553 endif # $(dot-config)
 554
 555 # The all: target is the default when no target is given on the
 556 # command line.
 557 # This allow a user to issue only 'make' to build a kernel including modules
 558 # Defaults to vmlinux, but the arch makefile usually adds further targets
 559 all: vmlinux
 560
 561 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 562 KBUILD_CFLAGS   += -Os
 563 else
 564 KBUILD_CFLAGS   += -O2
 565 endif
 566
 567 include $(srctree)/arch/$(SRCARCH)/Makefile
 568
 569 ifneq ($(CONFIG_FRAME_WARN),0)
 570 KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
 571 endif
 572
 573 # Force gcc to behave correct even for buggy distributions
 574 ifndef CONFIG_CC_STACKPROTECTOR
 575 KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
 576 endif
 577
 578 # This warning generated too much noise in a regular build.
 579 # Use make W=1 to enable this warning (see scripts/Makefile.build)
 580 KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
 581
 582 ifdef CONFIG_FRAME_POINTER
 583 KBUILD_CFLAGS   += -fno-omit-frame-pointer -fno-optimize-sibling-calls
 584 else
 585 # Some targets (ARM with Thumb2, for example), can't be built with frame
 586 # pointers.  For those, we don't have FUNCTION_TRACER automatically
 587 # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
 588 # incompatible with -fomit-frame-pointer with current GCC, so we don't use
 589 # -fomit-frame-pointer with FUNCTION_TRACER.
 590 ifndef CONFIG_FUNCTION_TRACER
 591 KBUILD_CFLAGS   += -fomit-frame-pointer
 592 endif
 593 endif
 594
 595 ifdef CONFIG_DEBUG_INFO
 596 KBUILD_CFLAGS   += -g
 597 KBUILD_AFLAGS   += -gdwarf-2
 598 endif
 599
 600 ifdef CONFIG_DEBUG_INFO_REDUCED
 601 KBUILD_CFLAGS   += $(call cc-option, -femit-struct-debug-baseonly)
 602 endif
 603
 604 ifdef CONFIG_FUNCTION_TRACER
 605 KBUILD_CFLAGS   += -pg
 606 ifdef CONFIG_DYNAMIC_FTRACE
 607         ifdef CONFIG_HAVE_C_RECORDMCOUNT
 608                 BUILD_C_RECORDMCOUNT := y
 609                 export BUILD_C_RECORDMCOUNT
 610         endif
 611 endif
 612 endif
 613
 614 # We trigger additional mismatches with less inlining
 615 ifdef CONFIG_DEBUG_SECTION_MISMATCH
 616 KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once)
 617 endif
 618
 619 # arch Makefile may override CC so keep this after arch Makefile is included
 620 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 621 CHECKFLAGS     += $(NOSTDINC_FLAGS)
 622
 623 # warn about C99 declaration after statement
 624 KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
 625
 626 # disable pointer signed / unsigned warnings in gcc 4.0
 627 KBUILD_CFLAGS += $(call cc-disable-warning, pointer-sign)
 628
 629 # disable invalid "can't wrap" optimizations for signed / pointers
 630 KBUILD_CFLAGS   += $(call cc-option,-fno-strict-overflow)
 631
 632 # conserve stack if available
 633 KBUILD_CFLAGS   += $(call cc-option,-fconserve-stack)
 634
 635 # use the deterministic mode of AR if available
 636 KBUILD_ARFLAGS := $(call ar-option,D)
 637
 638 # check for 'asm goto'
 639 ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
 640         KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
 641 endif
 642
 643 # Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
 644 # But warn user when we do so
 645 warn-assign = \
 646 $(warning "WARNING: Appending $$K$(1) ($(K$(1))) from $(origin K$(1)) to kernel $$$(1)")
 647
 648 ifneq ($(KCPPFLAGS),)
 649         $(call warn-assign,CPPFLAGS)
 650         KBUILD_CPPFLAGS += $(KCPPFLAGS)
 651 endif
 652 ifneq ($(KAFLAGS),)
 653         $(call warn-assign,AFLAGS)
 654         KBUILD_AFLAGS += $(KAFLAGS)
 655 endif
 656 ifneq ($(KCFLAGS),)
 657         $(call warn-assign,CFLAGS)
 658         KBUILD_CFLAGS += $(KCFLAGS)
 659 endif
 660
 661 # Use --build-id when available.
 662 LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
 663                               $(call cc-ldoption, -Wl$(comma)--build-id,))
 664 KBUILD_LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
 665 LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)
 666
 667 ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
 668 LDFLAGS_vmlinux += $(call ld-option, -X,)
 669 endif
 670
 671 # Default kernel image to build when no specific target is given.
 672 # KBUILD_IMAGE may be overruled on the command line or
 673 # set in the environment
 674 # Also any assignments in arch/$(ARCH)/Makefile take precedence over
 675 # this default value
 676 export KBUILD_IMAGE ?= vmlinux
 677
 678 #
 679 # INSTALL_PATH specifies where to place the updated kernel and system map
 680 # images. Default is /boot, but you can set it to other values
 681 export  INSTALL_PATH ?= /boot
 682
 683 #
 684 # INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
 685 # relocations required by build roots.  This is not defined in the
 686 # makefile but the argument can be passed to make if needed.
 687 #
 688
 689 MODLIB  = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
 690 export MODLIB
 691
 692 #
 693 #  INSTALL_MOD_STRIP, if defined, will cause modules to be
 694 #  stripped after they are installed.  If INSTALL_MOD_STRIP is '1', then
 695 #  the default option --strip-debug will be used.  Otherwise,
 696 #  INSTALL_MOD_STRIP value will be used as the options to the strip command.
 697
 698 ifdef INSTALL_MOD_STRIP
 699 ifeq ($(INSTALL_MOD_STRIP),1)
 700 mod_strip_cmd = $(STRIP) --strip-debug
 701 else
 702 mod_strip_cmd = $(STRIP) $(INSTALL_MOD_STRIP)
 703 endif # INSTALL_MOD_STRIP=1
 704 else
 705 mod_strip_cmd = true
 706 endif # INSTALL_MOD_STRIP
 707 export mod_strip_cmd
 708
 709
 710 ifeq ($(KBUILD_EXTMOD),)
 711 core-y          += kernel/ mm/ fs/ ipc/ security/ crypto/ block/
 712
 713 vmlinux-dirs    := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
 714                      $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
 715                      $(net-y) $(net-m) $(libs-y) $(libs-m)))
 716
 717 vmlinux-alldirs := $(sort $(vmlinux-dirs) $(patsubst %/,%,$(filter %/, \
 718                      $(init-n) $(init-) \
 719                      $(core-n) $(core-) $(drivers-n) $(drivers-) \
 720                      $(net-n)  $(net-)  $(libs-n)    $(libs-))))
 721
 722 init-y          := $(patsubst %/, %/built-in.o, $(init-y))
 723 core-y          := $(patsubst %/, %/built-in.o, $(core-y))
 724 drivers-y       := $(patsubst %/, %/built-in.o, $(drivers-y))
 725 net-y           := $(patsubst %/, %/built-in.o, $(net-y))
 726 libs-y1         := $(patsubst %/, %/lib.a, $(libs-y))
 727 libs-y2         := $(patsubst %/, %/built-in.o, $(libs-y))
 728 libs-y          := $(libs-y1) $(libs-y2)
 729
 730 # Build vmlinux
 731 # ---------------------------------------------------------------------------
 732 # vmlinux is built from the objects selected by $(vmlinux-init) and
 733 # $(vmlinux-main). Most are built-in.o files from top-level directories
 734 # in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
 735 # Ordering when linking is important, and $(vmlinux-init) must be first.
 736 #
 737 # vmlinux
 738 #   ^
 739 #   |
 740 #   +-< $(vmlinux-init)
 741 #   |   +--< init/version.o + more
 742 #   |
 743 #   +--< $(vmlinux-main)
 744 #   |    +--< driver/built-in.o mm/built-in.o + more
 745 #   |
 746 #   +-< kallsyms.o (see description in CONFIG_KALLSYMS section)
 747 #
 748 # vmlinux version (uname -v) cannot be updated during normal
 749 # descending-into-subdirs phase since we do not yet know if we need to
 750 # update vmlinux.
 751 # Therefore this step is delayed until just before final link of vmlinux -
 752 # except in the kallsyms case where it is done just before adding the
 753 # symbols to the kernel.
 754 #
 755 # System.map is generated to document addresses of all kernel symbols
 756
 757 vmlinux-init := $(head-y) $(init-y)
 758 vmlinux-main := $(core-y) $(libs-y) $(drivers-y) $(net-y)
 759 vmlinux-all  := $(vmlinux-init) $(vmlinux-main)
 760 vmlinux-lds  := arch/$(SRCARCH)/kernel/vmlinux.lds
 761 export KBUILD_VMLINUX_OBJS := $(vmlinux-all)
 762
 763 # Rule to link vmlinux - also used during CONFIG_KALLSYMS
 764 # May be overridden by arch/$(ARCH)/Makefile
 765 quiet_cmd_vmlinux__ ?= LD      $@
 766       cmd_vmlinux__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) -o $@ \
 767       -T $(vmlinux-lds) $(vmlinux-init)                          \
 768       --start-group $(vmlinux-main) --end-group                  \
 769       $(filter-out $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o FORCE ,$^)
 770
 771 # Generate new vmlinux version
 772 quiet_cmd_vmlinux_version = GEN     .version
 773       cmd_vmlinux_version = set -e;                     \
 774         if [ ! -r .version ]; then                      \
 775           rm -f .version;                               \
 776           echo 1 >.version;                             \
 777         else                                            \
 778           mv .version .old_version;                     \
 779           expr 0$$(cat .old_version) + 1 >.version;     \
 780         fi;                                             \
 781         $(MAKE) $(build)=init
 782
 783 # Generate System.map
 784 quiet_cmd_sysmap = SYSMAP
 785       cmd_sysmap = $(CONFIG_SHELL) $(srctree)/scripts/mksysmap
 786
 787 # Link of vmlinux
 788 # If CONFIG_KALLSYMS is set .version is already updated
 789 # Generate System.map and verify that the content is consistent
 790 # Use + in front of the vmlinux_version rule to silent warning with make -j2
 791 # First command is ':' to allow us to use + in front of the rule
 792 define rule_vmlinux__
 793         :
 794         $(if $(CONFIG_KALLSYMS),,+$(call cmd,vmlinux_version))
 795
 796         $(call cmd,vmlinux__)
 797         $(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
 798
 799         $(Q)$(if $($(quiet)cmd_sysmap),                                      \
 800           echo '  $($(quiet)cmd_sysmap)  System.map' &&)                     \
 801         $(cmd_sysmap) $@ System.map;                                         \
 802         if [ $$? -ne 0 ]; then                                               \
 803                 rm -f $@;                                                    \
 804                 /bin/false;                                                  \
 805         fi;
 806         $(verify_kallsyms)
 807 endef
 808
 809
 810 ifdef CONFIG_KALLSYMS
 811 # Generate section listing all symbols and add it into vmlinux $(kallsyms.o)
 812 # It's a three stage process:
 813 # o .tmp_vmlinux1 has all symbols and sections, but __kallsyms is
 814 #   empty
 815 #   Running kallsyms on that gives us .tmp_kallsyms1.o with
 816 #   the right size - vmlinux version (uname -v) is updated during this step
 817 # o .tmp_vmlinux2 now has a __kallsyms section of the right size,
 818 #   but due to the added section, some addresses have shifted.
 819 #   From here, we generate a correct .tmp_kallsyms2.o
 820 # o The correct .tmp_kallsyms2.o is linked into the final vmlinux.
 821 # o Verify that the System.map from vmlinux matches the map from
 822 #   .tmp_vmlinux2, just in case we did not generate kallsyms correctly.
 823 # o If 'make KALLSYMS_EXTRA_PASS=1" was used, do an extra pass using
 824 #   .tmp_vmlinux3 and .tmp_kallsyms3.o.  This is only meant as a
 825 #   temporary bypass to allow the kernel to be built while the
 826 #   maintainers work out what went wrong with kallsyms.
 827
 828 last_kallsyms := 2
 829
 830 ifdef KALLSYMS_EXTRA_PASS
 831 ifneq ($(KALLSYMS_EXTRA_PASS),0)
 832 last_kallsyms := 3
 833 endif
 834 endif
 835
 836 kallsyms.o := .tmp_kallsyms$(last_kallsyms).o
 837
 838 define verify_kallsyms
 839         $(Q)$(if $($(quiet)cmd_sysmap),                                      \
 840           echo '  $($(quiet)cmd_sysmap)  .tmp_System.map' &&)                \
 841           $(cmd_sysmap) .tmp_vmlinux$(last_kallsyms) .tmp_System.map
 842         $(Q)cmp -s System.map .tmp_System.map ||                             \
 843                 (echo Inconsistent kallsyms data;                            \
 844                  echo This is a bug - please report about it;                \
 845                  echo Try "make KALLSYMS_EXTRA_PASS=1" as a workaround;      \
 846                  rm .tmp_kallsyms* ; /bin/false )
 847 endef
 848
 849 # Update vmlinux version before link
 850 # Use + in front of this rule to silent warning about make -j1
 851 # First command is ':' to allow us to use + in front of this rule
 852 cmd_ksym_ld = $(cmd_vmlinux__)
 853 define rule_ksym_ld
 854         :
 855         +$(call cmd,vmlinux_version)
 856         $(call cmd,vmlinux__)
 857         $(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
 858 endef
 859
 860 # Generate .S file with all kernel symbols
 861 quiet_cmd_kallsyms = KSYM    $@
 862       cmd_kallsyms = $(NM) -n $< | $(KALLSYMS) \
 863                      $(if $(CONFIG_KALLSYMS_ALL),--all-symbols) > $@
 864
 865 .tmp_kallsyms1.o .tmp_kallsyms2.o .tmp_kallsyms3.o: %.o: %.S scripts FORCE
 866         $(call if_changed_dep,as_o_S)
 867
 868 .tmp_kallsyms%.S: .tmp_vmlinux% $(KALLSYMS)
 869         $(call cmd,kallsyms)
 870
 871 # .tmp_vmlinux1 must be complete except kallsyms, so update vmlinux version
 872 .tmp_vmlinux1: $(vmlinux-lds) $(vmlinux-all) FORCE
 873         $(call if_changed_rule,ksym_ld)
 874
 875 .tmp_vmlinux2: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms1.o FORCE
 876         $(call if_changed,vmlinux__)
 877
 878 .tmp_vmlinux3: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms2.o FORCE
 879         $(call if_changed,vmlinux__)
 880
 881 # Needs to visit scripts/ before $(KALLSYMS) can be used.
 882 $(KALLSYMS): scripts ;
 883
 884 # Generate some data for debugging strange kallsyms problems
 885 debug_kallsyms: .tmp_map$(last_kallsyms)
 886
 887 .tmp_map%: .tmp_vmlinux% FORCE
 888         ($(OBJDUMP) -h $< | $(AWK) '/^ +[0-9]/{print $$4 " 0 " $$2}'; $(NM) $<) | sort > $@
 889
 890 .tmp_map3: .tmp_map2
 891
 892 .tmp_map2: .tmp_map1
 893
 894 endif # ifdef CONFIG_KALLSYMS
 895
 896 # Do modpost on a prelinked vmlinux. The finally linked vmlinux has
 897 # relevant sections renamed as per the linker script.
 898 quiet_cmd_vmlinux-modpost = LD      $@
 899       cmd_vmlinux-modpost = $(LD) $(LDFLAGS) -r -o $@                          \
 900          $(vmlinux-init) --start-group $(vmlinux-main) --end-group             \
 901          $(filter-out $(vmlinux-init) $(vmlinux-main) FORCE ,$^)
 902 define rule_vmlinux-modpost
 903         :
 904         +$(call cmd,vmlinux-modpost)
 905         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost $@
 906         $(Q)echo 'cmd_$@ := $(cmd_vmlinux-modpost)' > $(dot-target).cmd
 907 endef
 908
 909 # vmlinux image - including updated kernel symbols
 910 vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o $(kallsyms.o) FORCE
 911 ifdef CONFIG_HEADERS_CHECK
 912         $(Q)$(MAKE) -f $(srctree)/Makefile headers_check
 913 endif
 914 ifdef CONFIG_SAMPLES
 915         $(Q)$(MAKE) $(build)=samples
 916 endif
 917 ifdef CONFIG_BUILD_DOCSRC
 918         $(Q)$(MAKE) $(build)=Documentation
 919 endif
 920         $(call vmlinux-modpost)
 921         $(call if_changed_rule,vmlinux__)
 922         $(Q)rm -f .old_version
 923
 924 # build vmlinux.o first to catch section mismatch errors early
 925 ifdef CONFIG_KALLSYMS
 926 .tmp_vmlinux1: vmlinux.o
 927 endif
 928
 929 modpost-init := $(filter-out init/built-in.o, $(vmlinux-init))
 930 vmlinux.o: $(modpost-init) $(vmlinux-main) FORCE
 931         $(call if_changed_rule,vmlinux-modpost)
 932
 933 # The actual objects are generated when descending,
 934 # make sure no implicit rule kicks in
 935 $(sort $(vmlinux-init) $(vmlinux-main)) $(vmlinux-lds): $(vmlinux-dirs) ;
 936
 937 # Handle descending into subdirectories listed in $(vmlinux-dirs)
 938 # Preset locale variables to speed up the build process. Limit locale
 939 # tweaks to this spot to avoid wrong language settings when running
 940 # make menuconfig etc.
 941 # Error messages still appears in the original language
 942
 943 PHONY += $(vmlinux-dirs)
 944 $(vmlinux-dirs): prepare scripts
 945         $(Q)$(MAKE) $(build)=$@
 946
 947 # Store (new) KERNELRELASE string in include/config/kernel.release
 948 include/config/kernel.release: include/config/auto.conf FORCE
 949         $(Q)rm -f $@
 950         $(Q)echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))" > $@
 951
 952
 953 # Things we need to do before we recursively start building the kernel
 954 # or the modules are listed in "prepare".
 955 # A multi level approach is used. prepareN is processed before prepareN-1.
 956 # archprepare is used in arch Makefiles and when processed asm symlink,
 957 # version.h and scripts_basic is processed / created.
 958
 959 # Listed in dependency order
 960 PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3
 961
 962 # prepare3 is used to check if we are building in a separate output directory,
 963 # and if so do:
 964 # 1) Check that make has not been executed in the kernel src $(srctree)
 965 prepare3: include/config/kernel.release
 966 ifneq ($(KBUILD_SRC),)
 967         @$(kecho) '  Using $(srctree) as source for kernel'
 968         $(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \
 969                 echo "  $(srctree) is not clean, please run 'make mrproper'";\
 970                 echo "  in the '$(srctree)' directory.";\
 971                 /bin/false; \
 972         fi;
 973 endif
 974
 975 # prepare2 creates a makefile if using a separate output directory
 976 prepare2: prepare3 outputmakefile asm-generic
 977
 978 prepare1: prepare2 include/linux/version.h include/generated/utsrelease.h \
 979                    include/config/auto.conf
 980         $(cmd_crmodverdir)
 981
 982 archprepare: prepare1 scripts_basic
 983
 984 prepare0: archprepare FORCE
 985         $(Q)$(MAKE) $(build)=.
 986
 987 # All the preparing..
 988 prepare: prepare0
 989
 990 # Generate some files
 991 # ---------------------------------------------------------------------------
 992
 993 # KERNELRELEASE can change from a few different places, meaning version.h
 994 # needs to be updated, so this check is forced on all builds
 995
 996 uts_len := 64
 997 define filechk_utsrelease.h
 998         if [ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt $(uts_len) ]; then \
 999           echo '"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2;    \
1000           exit 1;                                                         \
1001         fi;                                                               \
1002         (echo \#define UTS_RELEASE \"$(KERNELRELEASE)\";)
1003 endef
1004
1005 define filechk_version.h
1006         (echo \#define LINUX_VERSION_CODE $(shell                             \
1007         expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 0$(SUBLEVEL));    \
1008         echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))';)
1009 endef
1010
1011 include/linux/version.h: $(srctree)/Makefile FORCE
1012         $(call filechk,version.h)
1013
1014 include/generated/utsrelease.h: include/config/kernel.release FORCE
1015         $(call filechk,utsrelease.h)
1016
1017 PHONY += headerdep
1018 headerdep:
1019         $(Q)find $(srctree)/include/ -name '*.h' | xargs --max-args 1 \
1020         $(srctree)/scripts/headerdep.pl -I$(srctree)/include
1021
1022 # ---------------------------------------------------------------------------
1023
1024 PHONY += depend dep
1025 depend dep:
1026         @echo '*** Warning: make $@ is unnecessary now.'
1027
1028 # ---------------------------------------------------------------------------
1029 # Firmware install
1030 INSTALL_FW_PATH=$(INSTALL_MOD_PATH)/lib/firmware
1031 export INSTALL_FW_PATH
1032
1033 PHONY += firmware_install
1034 firmware_install: FORCE
1035         @mkdir -p $(objtree)/firmware
1036         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_install
1037
1038 # ---------------------------------------------------------------------------
1039 # Kernel headers
1040
1041 #Default location for installed headers
1042 export INSTALL_HDR_PATH = $(objtree)/usr
1043
1044 hdr-inst := -rR -f $(srctree)/scripts/Makefile.headersinst obj
1045
1046 # If we do an all arch process set dst to asm-$(hdr-arch)
1047 hdr-dst = $(if $(KBUILD_HEADERS), dst=include/asm-$(hdr-arch), dst=include/asm)
1048
1049 PHONY += __headers
1050 __headers: include/linux/version.h scripts_basic asm-generic FORCE
1051         $(Q)$(MAKE) $(build)=scripts build_unifdef
1052
1053 PHONY += headers_install_all
1054 headers_install_all:
1055         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh install
1056
1057 PHONY += headers_install
1058 headers_install: __headers
1059         $(if $(wildcard $(srctree)/arch/$(hdr-arch)/include/asm/Kbuild),, \
1060         $(error Headers not exportable for the $(SRCARCH) architecture))
1061         $(Q)$(MAKE) $(hdr-inst)=include
1062         $(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/asm $(hdr-dst)
1063
1064 PHONY += headers_check_all
1065 headers_check_all: headers_install_all
1066         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh check
1067
1068 PHONY += headers_check
1069 headers_check: headers_install
1070         $(Q)$(MAKE) $(hdr-inst)=include HDRCHECK=1
1071         $(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/asm $(hdr-dst) HDRCHECK=1
1072
1073 # ---------------------------------------------------------------------------
1074 # Modules
1075
1076 ifdef CONFIG_MODULES
1077
1078 # By default, build modules as well
1079
1080 all: modules
1081
1082 #       Build modules
1083 #
1084 #       A module can be listed more than once in obj-m resulting in
1085 #       duplicate lines in modules.order files.  Those are removed
1086 #       using awk while concatenating to the final file.
1087
1088 PHONY += modules
1089 modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin
1090         $(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order
1091         @$(kecho) '  Building modules, stage 2.';
1092         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1093         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modbuild
1094
1095 modules.builtin: $(vmlinux-dirs:%=%/modules.builtin)
1096         $(Q)$(AWK) '!x[$$0]++' $^ > $(objtree)/modules.builtin
1097
1098 %/modules.builtin: include/config/auto.conf
1099         $(Q)$(MAKE) $(modbuiltin)=$*
1100
1101
1102 # Target to prepare building external modules
1103 PHONY += modules_prepare
1104 modules_prepare: prepare scripts
1105
1106 # Target to install modules
1107 PHONY += modules_install
1108 modules_install: _modinst_ _modinst_post
1109
1110 PHONY += _modinst_
1111 _modinst_:
1112         @rm -rf $(MODLIB)/kernel
1113         @rm -f $(MODLIB)/source
1114         @mkdir -p $(MODLIB)/kernel
1115         @ln -s $(srctree) $(MODLIB)/source
1116         @if [ ! $(objtree) -ef  $(MODLIB)/build ]; then \
1117                 rm -f $(MODLIB)/build ; \
1118                 ln -s $(objtree) $(MODLIB)/build ; \
1119         fi
1120         @cp -f $(objtree)/modules.order $(MODLIB)/
1121         @cp -f $(objtree)/modules.builtin $(MODLIB)/
1122         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
1123
1124 # This depmod is only for convenience to give the initial
1125 # boot a modules.dep even before / is mounted read-write.  However the
1126 # boot script depmod is the master version.
1127 PHONY += _modinst_post
1128 _modinst_post: _modinst_
1129         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modinst
1130         $(call cmd,depmod)
1131
1132 else # CONFIG_MODULES
1133
1134 # Modules not configured
1135 # ---------------------------------------------------------------------------
1136
1137 modules modules_install: FORCE
1138         @echo
1139         @echo "The present kernel configuration has modules disabled."
1140         @echo "Type 'make config' and enable loadable module support."
1141         @echo "Then build a kernel with module support enabled."
1142         @echo
1143         @exit 1
1144
1145 endif # CONFIG_MODULES
1146
1147 ###
1148 # Cleaning is done on three levels.
1149 # make clean     Delete most generated files
1150 #                Leave enough to build external modules
1151 # make mrproper  Delete the current configuration, and all generated files
1152 # make distclean Remove editor backup files, patch leftover files and the like
1153
1154 # Directories & files removed with 'make clean'
1155 CLEAN_DIRS  += $(MODVERDIR)
1156 CLEAN_FILES +=  vmlinux System.map \
1157                 .tmp_kallsyms* .tmp_version .tmp_vmlinux* .tmp_System.map
1158
1159 # Directories & files removed with 'make mrproper'
1160 MRPROPER_DIRS  += include/config usr/include include/generated          \
1161                   arch/*/include/generated
1162 MRPROPER_FILES += .config .config.old .version .old_version             \
1163                   include/linux/version.h                               \
1164                   Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
1165
1166 # clean - Delete most, but leave enough to build external modules
1167 #
1168 clean: rm-dirs  := $(CLEAN_DIRS)
1169 clean: rm-files := $(CLEAN_FILES)
1170 clean-dirs      := $(addprefix _clean_, . $(vmlinux-alldirs) Documentation)
1171
1172 PHONY += $(clean-dirs) clean archclean
1173 $(clean-dirs):
1174         $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
1175
1176 clean: archclean
1177
1178 # mrproper - Delete all generated files, including .config
1179 #
1180 mrproper: rm-dirs  := $(wildcard $(MRPROPER_DIRS))
1181 mrproper: rm-files := $(wildcard $(MRPROPER_FILES))
1182 mrproper-dirs      := $(addprefix _mrproper_,Documentation/DocBook scripts)
1183
1184 PHONY += $(mrproper-dirs) mrproper archmrproper
1185 $(mrproper-dirs):
1186         $(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@)
1187
1188 mrproper: clean archmrproper $(mrproper-dirs)
1189         $(call cmd,rmdirs)
1190         $(call cmd,rmfiles)
1191
1192 # distclean
1193 #
1194 PHONY += distclean
1195
1196 distclean: mrproper
1197         @find $(srctree) $(RCS_FIND_IGNORE) \
1198                 \( -name '*.orig' -o -name '*.rej' -o -name '*~' \
1199                 -o -name '*.bak' -o -name '#*#' -o -name '.*.orig' \
1200                 -o -name '.*.rej' \
1201                 -o -name '*%' -o -name '.*.cmd' -o -name 'core' \) \
1202                 -type f -print | xargs rm -f
1203
1204
1205 # Packaging of the kernel to various formats
1206 # ---------------------------------------------------------------------------
1207 # rpm target kept for backward compatibility
1208 package-dir     := $(srctree)/scripts/package
1209
1210 %src-pkg: FORCE
1211         $(Q)$(MAKE) $(build)=$(package-dir) $@
1212 %pkg: include/config/kernel.release FORCE
1213         $(Q)$(MAKE) $(build)=$(package-dir) $@
1214 rpm: include/config/kernel.release FORCE
1215         $(Q)$(MAKE) $(build)=$(package-dir) $@
1216
1217
1218 # Brief documentation of the typical targets used
1219 # ---------------------------------------------------------------------------
1220
1221 boards := $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*_defconfig)
1222 boards := $(notdir $(boards))
1223 board-dirs := $(dir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*/*_defconfig))
1224 board-dirs := $(sort $(notdir $(board-dirs:/=)))
1225
1226 help:
1227         @echo  'Cleaning targets:'
1228         @echo  '  clean           - Remove most generated files but keep the config and'
1229         @echo  '                    enough build support to build external modules'
1230         @echo  '  mrproper        - Remove all generated files + config + various backup files'
1231         @echo  '  distclean       - mrproper + remove editor backup and patch files'
1232         @echo  ''
1233         @echo  'Configuration targets:'
1234         @$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
1235         @echo  ''
1236         @echo  'Other generic targets:'
1237         @echo  '  all             - Build all targets marked with [*]'
1238         @echo  '* vmlinux         - Build the bare kernel'
1239         @echo  '* modules         - Build all modules'
1240         @echo  '  modules_install - Install all modules to INSTALL_MOD_PATH (default: /)'
1241         @echo  '  firmware_install- Install all firmware to INSTALL_FW_PATH'
1242         @echo  '                    (default: $$(INSTALL_MOD_PATH)/lib/firmware)'
1243         @echo  '  dir/            - Build all files in dir and below'
1244         @echo  '  dir/file.[oisS] - Build specified target only'
1245         @echo  '  dir/file.lst    - Build specified mixed source/assembly target only'
1246         @echo  '                    (requires a recent binutils and recent build (System.map))'
1247         @echo  '  dir/file.ko     - Build module including final link'
1248         @echo  '  modules_prepare - Set up for building external modules'
1249         @echo  '  tags/TAGS       - Generate tags file for editors'
1250         @echo  '  cscope          - Generate cscope index'
1251         @echo  '  gtags           - Generate GNU GLOBAL index'
1252         @echo  '  kernelrelease   - Output the release version string'
1253         @echo  '  kernelversion   - Output the version stored in Makefile'
1254         @echo  '  headers_install - Install sanitised kernel headers to INSTALL_HDR_PATH'; \
1255          echo  '                    (default: $(INSTALL_HDR_PATH))'; \
1256          echo  ''
1257         @echo  'Static analysers'
1258         @echo  '  checkstack      - Generate a list of stack hogs'
1259         @echo  '  namespacecheck  - Name space analysis on compiled kernel'
1260         @echo  '  versioncheck    - Sanity check on version.h usage'
1261         @echo  '  includecheck    - Check for duplicate included header files'
1262         @echo  '  export_report   - List the usages of all exported symbols'
1263         @echo  '  headers_check   - Sanity check on exported headers'
1264         @echo  '  headerdep       - Detect inclusion cycles in headers'
1265         @$(MAKE) -f $(srctree)/scripts/Makefile.help checker-help
1266         @echo  ''
1267         @echo  'Kernel packaging:'
1268         @$(MAKE) $(build)=$(package-dir) help
1269         @echo  ''
1270         @echo  'Documentation targets:'
1271         @$(MAKE) -f $(srctree)/Documentation/DocBook/Makefile dochelp
1272         @echo  ''
1273         @echo  'Architecture specific targets ($(SRCARCH)):'
1274         @$(if $(archhelp),$(archhelp),\
1275                 echo '  No architecture specific help defined for $(SRCARCH)')
1276         @echo  ''
1277         @$(if $(boards), \
1278                 $(foreach b, $(boards), \
1279                 printf "  %-24s - Build for %s\\n" $(b) $(subst _defconfig,,$(b));) \
1280                 echo '')
1281         @$(if $(board-dirs), \
1282                 $(foreach b, $(board-dirs), \
1283                 printf "  %-16s - Show %s-specific targets\\n" help-$(b) $(b);) \
1284                 printf "  %-16s - Show all of the above\\n" help-boards; \
1285                 echo '')
1286
1287         @echo  '  make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
1288         @echo  '  make V=2   [targets] 2 => give reason for rebuild of target'
1289         @echo  '  make O=dir [targets] Locate all output files in "dir", including .config'
1290         @echo  '  make C=1   [targets] Check all c source with $$CHECK (sparse by default)'
1291         @echo  '  make C=2   [targets] Force check of all c source with $$CHECK'
1292         @echo  '  make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections'
1293         @echo  '  make W=n   [targets] Enable extra gcc checks, n=1,2,3 where'
1294         @echo  '                1: warnings which may be relevant and do not occur too often'
1295         @echo  '                2: warnings which occur quite often but may still be relevant'
1296         @echo  '                3: more obscure warnings, can most likely be ignored'
1297         @echo  '                Multiple levels can be combined with W=12 or W=123'
1298         @echo  ''
1299         @echo  'Execute "make" or "make all" to build all targets marked with [*] '
1300         @echo  'For further info see the ./README file'
1301
1302
1303 help-board-dirs := $(addprefix help-,$(board-dirs))
1304
1305 help-boards: $(help-board-dirs)
1306
1307 boards-per-dir = $(notdir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/$*/*_defconfig))
1308
1309 $(help-board-dirs): help-%:
1310         @echo  'Architecture specific targets ($(SRCARCH) $*):'
1311         @$(if $(boards-per-dir), \
1312                 $(foreach b, $(boards-per-dir), \
1313                 printf "  %-24s - Build for %s\\n" $*/$(b) $(subst _defconfig,,$(b));) \
1314                 echo '')
1315
1316
1317 # Documentation targets
1318 # ---------------------------------------------------------------------------
1319 %docs: scripts_basic FORCE
1320         $(Q)$(MAKE) $(build)=scripts build_docproc
1321         $(Q)$(MAKE) $(build)=Documentation/DocBook $@
1322
1323 else # KBUILD_EXTMOD
1324
1325 ###
1326 # External module support.
1327 # When building external modules the kernel used as basis is considered
1328 # read-only, and no consistency checks are made and the make
1329 # system is not used on the basis kernel. If updates are required
1330 # in the basis kernel ordinary make commands (without M=...) must
1331 # be used.
1332 #
1333 # The following are the only valid targets when building external
1334 # modules.
1335 # make M=dir clean     Delete all automatically generated files
1336 # make M=dir modules   Make all modules in specified dir
1337 # make M=dir           Same as 'make M=dir modules'
1338 # make M=dir modules_install
1339 #                      Install the modules built in the module directory
1340 #                      Assumes install directory is already created
1341
1342 # We are always building modules
1343 KBUILD_MODULES := 1
1344 PHONY += crmodverdir
1345 crmodverdir:
1346         $(cmd_crmodverdir)
1347
1348 PHONY += $(objtree)/Module.symvers
1349 $(objtree)/Module.symvers:
1350         @test -e $(objtree)/Module.symvers || ( \
1351         echo; \
1352         echo "  WARNING: Symbol version dump $(objtree)/Module.symvers"; \
1353         echo "           is missing; modules will have no dependencies and modversions."; \
1354         echo )
1355
1356 module-dirs := $(addprefix _module_,$(KBUILD_EXTMOD))
1357 PHONY += $(module-dirs) modules
1358 $(module-dirs): crmodverdir $(objtree)/Module.symvers
1359         $(Q)$(MAKE) $(build)=$(patsubst _module_%,%,$@)
1360
1361 modules: $(module-dirs)
1362         @$(kecho) '  Building modules, stage 2.';
1363         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1364
1365 PHONY += modules_install
1366 modules_install: _emodinst_ _emodinst_post
1367
1368 install-dir := $(if $(INSTALL_MOD_DIR),$(INSTALL_MOD_DIR),extra)
1369 PHONY += _emodinst_
1370 _emodinst_:
1371         $(Q)mkdir -p $(MODLIB)/$(install-dir)
1372         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
1373
1374 PHONY += _emodinst_post
1375 _emodinst_post: _emodinst_
1376         $(call cmd,depmod)
1377
1378 clean-dirs := $(addprefix _clean_,$(KBUILD_EXTMOD))
1379
1380 PHONY += $(clean-dirs) clean
1381 $(clean-dirs):
1382         $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
1383
1384 clean:  rm-dirs := $(MODVERDIR)
1385 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
1386
1387 help:
1388         @echo  '  Building external modules.'
1389         @echo  '  Syntax: make -C path/to/kernel/src M=$$PWD target'
1390         @echo  ''
1391         @echo  '  modules         - default target, build the module(s)'
1392         @echo  '  modules_install - install the module'
1393         @echo  '  clean           - remove generated files in module directory only'
1394         @echo  ''
1395
1396 # Dummies...
1397 PHONY += prepare scripts
1398 prepare: ;
1399 scripts: ;
1400 endif # KBUILD_EXTMOD
1401
1402 clean: $(clean-dirs)
1403         $(call cmd,rmdirs)
1404         $(call cmd,rmfiles)
1405         @find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
1406                 \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
1407                 -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
1408                 -o -name '*.symtypes' -o -name 'modules.order' \
1409                 -o -name modules.builtin -o -name '.tmp_*.o.*' \
1410                 -o -name '*.gcno' \) -type f -print | xargs rm -f
1411
1412 # Generate tags for editors
1413 # ---------------------------------------------------------------------------
1414 quiet_cmd_tags = GEN     $@
1415       cmd_tags = $(CONFIG_SHELL) $(srctree)/scripts/tags.sh $@
1416
1417 tags TAGS cscope gtags: FORCE
1418         $(call cmd,tags)
1419
1420 # Scripts to check various things for consistency
1421 # ---------------------------------------------------------------------------
1422
1423 PHONY += includecheck versioncheck coccicheck namespacecheck export_report
1424
1425 includecheck:
1426         find $(srctree)/* $(RCS_FIND_IGNORE) \
1427                 -name '*.[hcS]' -type f -print | sort \
1428                 | xargs $(PERL) -w $(srctree)/scripts/checkincludes.pl
1429
1430 versioncheck:
1431         find $(srctree)/* $(RCS_FIND_IGNORE) \
1432                 -name '*.[hcS]' -type f -print | sort \
1433                 | xargs $(PERL) -w $(srctree)/scripts/checkversion.pl
1434
1435 coccicheck:
1436         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
1437
1438 namespacecheck:
1439         $(PERL) $(srctree)/scripts/namespace.pl
1440
1441 export_report:
1442         $(PERL) $(srctree)/scripts/export_report.pl
1443
1444 endif #ifeq ($(config-targets),1)
1445 endif #ifeq ($(mixed-targets),1)
1446
1447 PHONY += checkstack kernelrelease kernelversion
1448
1449 # UML needs a little special treatment here.  It wants to use the host
1450 # toolchain, so needs $(SUBARCH) passed to checkstack.pl.  Everyone
1451 # else wants $(ARCH), including people doing cross-builds, which means
1452 # that $(SUBARCH) doesn't work here.
1453 ifeq ($(ARCH), um)
1454 CHECKSTACK_ARCH := $(SUBARCH)
1455 else
1456 CHECKSTACK_ARCH := $(ARCH)
1457 endif
1458 checkstack:
1459         $(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
1460         $(PERL) $(src)/scripts/checkstack.pl $(CHECKSTACK_ARCH)
1461
1462 kernelrelease:
1463         @echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
1464
1465 kernelversion:
1466         @echo $(KERNELVERSION)
1467
1468 # Single targets
1469 # ---------------------------------------------------------------------------
1470 # Single targets are compatible with:
1471 # - build with mixed source and output
1472 # - build with separate output dir 'make O=...'
1473 # - external modules
1474 #
1475 #  target-dir => where to store outputfile
1476 #  build-dir  => directory in kernel source tree to use
1477
1478 ifeq ($(KBUILD_EXTMOD),)
1479         build-dir  = $(patsubst %/,%,$(dir $@))
1480         target-dir = $(dir $@)
1481 else
1482         zap-slash=$(filter-out .,$(patsubst %/,%,$(dir $@)))
1483         build-dir  = $(KBUILD_EXTMOD)$(if $(zap-slash),/$(zap-slash))
1484         target-dir = $(if $(KBUILD_EXTMOD),$(dir $<),$(dir $@))
1485 endif
1486
1487 %.s: %.c prepare scripts FORCE
1488         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1489 %.i: %.c prepare scripts FORCE
1490         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1491 %.o: %.c prepare scripts FORCE
1492         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1493 %.lst: %.c prepare scripts FORCE
1494         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1495 %.s: %.S prepare scripts FORCE
1496         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1497 %.o: %.S prepare scripts FORCE
1498         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1499 %.symtypes: %.c prepare scripts FORCE
1500         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1501
1502 # Modules
1503 /: prepare scripts FORCE
1504         $(cmd_crmodverdir)
1505         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) \
1506         $(build)=$(build-dir)
1507 %/: prepare scripts FORCE
1508         $(cmd_crmodverdir)
1509         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) \
1510         $(build)=$(build-dir)
1511 %.ko: prepare scripts FORCE
1512         $(cmd_crmodverdir)
1513         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1)   \
1514         $(build)=$(build-dir) $(@:.ko=.o)
1515         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1516
1517 # FIXME Should go into a make.lib or something
1518 # ===========================================================================
1519
1520 quiet_cmd_rmdirs = $(if $(wildcard $(rm-dirs)),CLEAN   $(wildcard $(rm-dirs)))
1521       cmd_rmdirs = rm -rf $(rm-dirs)
1522
1523 quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN   $(wildcard $(rm-files)))
1524       cmd_rmfiles = rm -f $(rm-files)
1525
1526 # Run depmod only if we have System.map and depmod is executable
1527 quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)
1528       cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \
1529                    $(KERNELRELEASE)
1530
1531 # Create temporary dir for module support files
1532 # clean it up only when building all modules
1533 cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
1534                   $(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)
1535
1536 a_flags = -Wp,-MD,$(depfile) $(KBUILD_AFLAGS) $(AFLAGS_KERNEL) \
1537           $(KBUILD_AFLAGS_KERNEL)                              \
1538           $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(KBUILD_CPPFLAGS) \
1539           $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)
1540
1541 quiet_cmd_as_o_S = AS      $@
1542 cmd_as_o_S       = $(CC) $(a_flags) -c -o $@ $<
1543
1544 # read all saved command lines
1545
1546 targets := $(wildcard $(sort $(targets)))
1547 cmd_files := $(wildcard .*.cmd $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
1548
1549 ifneq ($(cmd_files),)
1550   $(cmd_files): ;       # Do not try to update included dependency files
1551   include $(cmd_files)
1552 endif
1553
1554 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=dir
1555 # Usage:
1556 # $(Q)$(MAKE) $(clean)=dir
1557 clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj
1558
1559 endif   # skip-makefile
1560
1561 PHONY += FORCE
1562 FORCE:
1563
1564 # Declare the contents of the .PHONY variable as phony.  We keep that
1565 # information in a variable so we can use it in if_changed and friends.
1566 .PHONY: $(PHONY)