Makefile

   1 VERSION = 2
   2 PATCHLEVEL = 6
   3 SUBLEVEL = 29
   4 EXTRAVERSION = -rc5
   5 NAME = Erotic Pickled Herring
   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 # We are using a recursive build, so we need to do a little thinking
  20 # to get the ordering right.
  21 #
  22 # Most importantly: sub-Makefiles should only ever modify files in
  23 # their own directory. If in some directory we have a dependency on
  24 # a file in another dir (which doesn't happen often, but it's often
  25 # unavoidable when linking the built-in.o targets which finally
  26 # turn into vmlinux), we will call a sub make in that other dir, and
  27 # after that we are sure that everything which is in that other dir
  28 # is now up to date.
  29 #
  30 # The only cases where we need to modify files which have global
  31 # effects are thus separated out and done before the recursive
  32 # descending is started. They are now explicitly listed as the
  33 # prepare rule.
  34
  35 # To put more focus on warnings, be less verbose as default
  36 # Use 'make V=1' to see the full commands
  37
  38 ifdef V
  39   ifeq ("$(origin V)", "command line")
  40     KBUILD_VERBOSE = $(V)
  41   endif
  42 endif
  43 ifndef KBUILD_VERBOSE
  44   KBUILD_VERBOSE = 0
  45 endif
  46
  47 # Call a source code checker (by default, "sparse") as part of the
  48 # C compilation.
  49 #
  50 # Use 'make C=1' to enable checking of only re-compiled files.
  51 # Use 'make C=2' to enable checking of *all* source files, regardless
  52 # of whether they are re-compiled or not.
  53 #
  54 # See the file "Documentation/sparse.txt" for more details, including
  55 # where to get the "sparse" utility.
  56
  57 ifdef C
  58   ifeq ("$(origin C)", "command line")
  59     KBUILD_CHECKSRC = $(C)
  60   endif
  61 endif
  62 ifndef KBUILD_CHECKSRC
  63   KBUILD_CHECKSRC = 0
  64 endif
  65
  66 # Use make M=dir to specify directory of external module to build
  67 # Old syntax make ... SUBDIRS=$PWD is still supported
  68 # Setting the environment variable KBUILD_EXTMOD take precedence
  69 ifdef SUBDIRS
  70   KBUILD_EXTMOD ?= $(SUBDIRS)
  71 endif
  72 ifdef M
  73   ifeq ("$(origin M)", "command line")
  74     KBUILD_EXTMOD := $(M)
  75   endif
  76 endif
  77
  78
  79 # kbuild supports saving output files in a separate directory.
  80 # To locate output files in a separate directory two syntaxes are supported.
  81 # In both cases the working directory must be the root of the kernel src.
  82 # 1) O=
  83 # Use "make O=dir/to/store/output/files/"
  84 #
  85 # 2) Set KBUILD_OUTPUT
  86 # Set the environment variable KBUILD_OUTPUT to point to the directory
  87 # where the output files shall be placed.
  88 # export KBUILD_OUTPUT=dir/to/store/output/files/
  89 # make
  90 #
  91 # The O= assignment takes precedence over the KBUILD_OUTPUT environment
  92 # variable.
  93
  94
  95 # KBUILD_SRC is set on invocation of make in OBJ directory
  96 # KBUILD_SRC is not intended to be used by the regular user (for now)
  97 ifeq ($(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 ifdef O
 102   ifeq ("$(origin O)", "command line")
 103     KBUILD_OUTPUT := $(O)
 104   endif
 105 endif
 106
 107 # That's our default target when none is given on the command line
 108 PHONY := _all
 109 _all:
 110
 111 # Cancel implicit rules on top Makefile
 112 $(CURDIR)/Makefile Makefile: ;
 113
 114 ifneq ($(KBUILD_OUTPUT),)
 115 # Invoke a second make in the output directory, passing relevant variables
 116 # check that the output directory actually exists
 117 saved-output := $(KBUILD_OUTPUT)
 118 KBUILD_OUTPUT := $(shell cd $(KBUILD_OUTPUT) && /bin/pwd)
 119 $(if $(KBUILD_OUTPUT),, \
 120      $(error output directory "$(saved-output)" does not exist))
 121
 122 PHONY += $(MAKECMDGOALS) sub-make
 123
 124 $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
 125         $(Q)@:
 126
 127 sub-make: FORCE
 128         $(if $(KBUILD_VERBOSE:1=),@)$(MAKE) -C $(KBUILD_OUTPUT) \
 129         KBUILD_SRC=$(CURDIR) \
 130         KBUILD_EXTMOD="$(KBUILD_EXTMOD)" -f $(CURDIR)/Makefile \
 131         $(filter-out _all sub-make,$(MAKECMDGOALS))
 132
 133 # Leave processing to above invocation of make
 134 skip-makefile := 1
 135 endif # ifneq ($(KBUILD_OUTPUT),)
 136 endif # ifeq ($(KBUILD_SRC),)
 137
 138 # We process the rest of the Makefile if this is the final invocation of make
 139 ifeq ($(skip-makefile),)
 140
 141 # If building an external module we do not care about the all: rule
 142 # but instead _all depend on modules
 143 PHONY += all
 144 ifeq ($(KBUILD_EXTMOD),)
 145 _all: all
 146 else
 147 _all: modules
 148 endif
 149
 150 srctree         := $(if $(KBUILD_SRC),$(KBUILD_SRC),$(CURDIR))
 151 TOPDIR          := $(srctree)
 152 # FIXME - TOPDIR is obsolete, use srctree/objtree
 153 objtree         := $(CURDIR)
 154 src             := $(srctree)
 155 obj             := $(objtree)
 156
 157 VPATH           := $(srctree)$(if $(KBUILD_EXTMOD),:$(KBUILD_EXTMOD))
 158
 159 export srctree objtree VPATH TOPDIR
 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.*/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 # Default value for CROSS_COMPILE is not to prefix executables
 191 # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
 192 export KBUILD_BUILDHOST := $(SUBARCH)
 193 ARCH            ?= $(SUBARCH)
 194 CROSS_COMPILE   ?=
 195
 196 # Architecture as present in compile.h
 197 UTS_MACHINE     := $(ARCH)
 198 SRCARCH         := $(ARCH)
 199
 200 # Additional ARCH settings for x86
 201 ifeq ($(ARCH),i386)
 202         SRCARCH := x86
 203 endif
 204 ifeq ($(ARCH),x86_64)
 205         SRCARCH := x86
 206 endif
 207
 208 # Additional ARCH settings for sparc
 209 ifeq ($(ARCH),sparc64)
 210        SRCARCH := sparc
 211 endif
 212
 213 # Where to locate arch specific headers
 214 hdr-arch  := $(SRCARCH)
 215
 216 ifeq ($(ARCH),m68knommu)
 217        hdr-arch  := m68k
 218 endif
 219
 220 KCONFIG_CONFIG  ?= .config
 221
 222 # SHELL used by kbuild
 223 CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
 224           else if [ -x /bin/bash ]; then echo /bin/bash; \
 225           else echo sh; fi ; fi)
 226
 227 HOSTCC       = gcc
 228 HOSTCXX      = g++
 229 HOSTCFLAGS   = -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
 230 HOSTCXXFLAGS = -O2
 231
 232 # Decide whether to build built-in, modular, or both.
 233 # Normally, just do built-in.
 234
 235 KBUILD_MODULES :=
 236 KBUILD_BUILTIN := 1
 237
 238 #       If we have only "make modules", don't compile built-in objects.
 239 #       When we're building modules with modversions, we need to consider
 240 #       the built-in objects during the descend as well, in order to
 241 #       make sure the checksums are up to date before we record them.
 242
 243 ifeq ($(MAKECMDGOALS),modules)
 244   KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1)
 245 endif
 246
 247 #       If we have "make <whatever> modules", compile modules
 248 #       in addition to whatever we do anyway.
 249 #       Just "make" or "make all" shall build modules as well
 250
 251 ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
 252   KBUILD_MODULES := 1
 253 endif
 254
 255 ifeq ($(MAKECMDGOALS),)
 256   KBUILD_MODULES := 1
 257 endif
 258
 259 export KBUILD_MODULES KBUILD_BUILTIN
 260 export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD
 261
 262 # Beautify output
 263 # ---------------------------------------------------------------------------
 264 #
 265 # Normally, we echo the whole command before executing it. By making
 266 # that echo $($(quiet)$(cmd)), we now have the possibility to set
 267 # $(quiet) to choose other forms of output instead, e.g.
 268 #
 269 #         quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@
 270 #         cmd_cc_o_c       = $(CC) $(c_flags) -c -o $@ $<
 271 #
 272 # If $(quiet) is empty, the whole command will be printed.
 273 # If it is set to "quiet_", only the short version will be printed.
 274 # If it is set to "silent_", nothing will be printed at all, since
 275 # the variable $(silent_cmd_cc_o_c) doesn't exist.
 276 #
 277 # A simple variant is to prefix commands with $(Q) - that's useful
 278 # for commands that shall be hidden in non-verbose mode.
 279 #
 280 #       $(Q)ln $@ :<
 281 #
 282 # If KBUILD_VERBOSE equals 0 then the above command will be hidden.
 283 # If KBUILD_VERBOSE equals 1 then the above command is displayed.
 284
 285 ifeq ($(KBUILD_VERBOSE),1)
 286   quiet =
 287   Q =
 288 else
 289   quiet=quiet_
 290   Q = @
 291 endif
 292
 293 # If the user is running make -s (silent mode), suppress echoing of
 294 # commands
 295
 296 ifneq ($(findstring s,$(MAKEFLAGS)),)
 297   quiet=silent_
 298 endif
 299
 300 export quiet Q KBUILD_VERBOSE
 301
 302
 303 # Look for make include files relative to root of kernel src
 304 MAKEFLAGS += --include-dir=$(srctree)
 305
 306 # We need some generic definitions (do not try to remake the file).
 307 $(srctree)/scripts/Kbuild.include: ;
 308 include $(srctree)/scripts/Kbuild.include
 309
 310 # Make variables (CC, etc...)
 311
 312 AS              = $(CROSS_COMPILE)as
 313 LD              = $(CROSS_COMPILE)ld
 314 CC              = $(CROSS_COMPILE)gcc
 315 CPP             = $(CC) -E
 316 AR              = $(CROSS_COMPILE)ar
 317 NM              = $(CROSS_COMPILE)nm
 318 STRIP           = $(CROSS_COMPILE)strip
 319 OBJCOPY         = $(CROSS_COMPILE)objcopy
 320 OBJDUMP         = $(CROSS_COMPILE)objdump
 321 AWK             = awk
 322 GENKSYMS        = scripts/genksyms/genksyms
 323 DEPMOD          = /sbin/depmod
 324 KALLSYMS        = scripts/kallsyms
 325 PERL            = perl
 326 CHECK           = sparse
 327
 328 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
 329                   -Wbitwise -Wno-return-void $(CF)
 330 MODFLAGS        = -DMODULE
 331 CFLAGS_MODULE   = $(MODFLAGS)
 332 AFLAGS_MODULE   = $(MODFLAGS)
 333 LDFLAGS_MODULE  =
 334 CFLAGS_KERNEL   =
 335 AFLAGS_KERNEL   =
 336
 337
 338 # Use LINUXINCLUDE when you must reference the include/ directory.
 339 # Needed to be compatible with the O= option
 340 LINUXINCLUDE    := -Iinclude \
 341                    $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include) \
 342                    -I$(srctree)/arch/$(hdr-arch)/include               \
 343                    -include include/linux/autoconf.h
 344
 345 KBUILD_CPPFLAGS := -D__KERNEL__
 346
 347 KBUILD_CFLAGS   := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
 348                    -fno-strict-aliasing -fno-common \
 349                    -Werror-implicit-function-declaration
 350 KBUILD_AFLAGS   := -D__ASSEMBLY__
 351
 352 # Read KERNELRELEASE from include/config/kernel.release (if it exists)
 353 KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
 354 KERNELVERSION = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
 355
 356 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
 357 export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 358 export CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL UTS_MACHINE
 359 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 360
 361 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
 362 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
 363 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 364
 365 # When compiling out-of-tree modules, put MODVERDIR in the module
 366 # tree rather than in the kernel tree. The kernel tree might
 367 # even be read-only.
 368 export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
 369
 370 # Files to ignore in find ... statements
 371
 372 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
 373 export RCS_TAR_IGNORE := --exclude SCCS --exclude BitKeeper --exclude .svn --exclude CVS --exclude .pc --exclude .hg --exclude .git
 374
 375 # ===========================================================================
 376 # Rules shared between *config targets and build targets
 377
 378 # Basic helpers built in scripts/
 379 PHONY += scripts_basic
 380 scripts_basic:
 381         $(Q)$(MAKE) $(build)=scripts/basic
 382
 383 # To avoid any implicit rule to kick in, define an empty command.
 384 scripts/basic/%: scripts_basic ;
 385
 386 PHONY += outputmakefile
 387 # outputmakefile generates a Makefile in the output directory, if using a
 388 # separate output directory. This allows convenient use of make in the
 389 # output directory.
 390 outputmakefile:
 391 ifneq ($(KBUILD_SRC),)
 392         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile \
 393             $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)
 394 endif
 395
 396 # To make sure we do not include .config for any of the *config targets
 397 # catch them early, and hand them over to scripts/kconfig/Makefile
 398 # It is allowed to specify more targets when calling make, including
 399 # mixing *config targets and build targets.
 400 # For example 'make oldconfig all'.
 401 # Detect when mixed targets is specified, and make a second invocation
 402 # of make so .config is not included in this case either (for *config).
 403
 404 no-dot-config-targets := clean mrproper distclean \
 405                          cscope TAGS tags help %docs check% \
 406                          include/linux/version.h headers_% \
 407                          kernelrelease kernelversion
 408
 409 config-targets := 0
 410 mixed-targets  := 0
 411 dot-config     := 1
 412
 413 ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
 414         ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
 415                 dot-config := 0
 416         endif
 417 endif
 418
 419 ifeq ($(KBUILD_EXTMOD),)
 420         ifneq ($(filter config %config,$(MAKECMDGOALS)),)
 421                 config-targets := 1
 422                 ifneq ($(filter-out config %config,$(MAKECMDGOALS)),)
 423                         mixed-targets := 1
 424                 endif
 425         endif
 426 endif
 427
 428 ifeq ($(mixed-targets),1)
 429 # ===========================================================================
 430 # We're called with mixed targets (*config and build targets).
 431 # Handle them one by one.
 432
 433 %:: FORCE
 434         $(Q)$(MAKE) -C $(srctree) KBUILD_SRC= $@
 435
 436 else
 437 ifeq ($(config-targets),1)
 438 # ===========================================================================
 439 # *config targets only - make sure prerequisites are updated, and descend
 440 # in scripts/kconfig to make the *config target
 441
 442 # Read arch specific Makefile to set KBUILD_DEFCONFIG as needed.
 443 # KBUILD_DEFCONFIG may point out an alternative default configuration
 444 # used for 'make defconfig'
 445 include $(srctree)/arch/$(SRCARCH)/Makefile
 446 export KBUILD_DEFCONFIG KBUILD_KCONFIG
 447
 448 config: scripts_basic outputmakefile FORCE
 449         $(Q)mkdir -p include/linux include/config
 450         $(Q)$(MAKE) $(build)=scripts/kconfig $@
 451
 452 %config: scripts_basic outputmakefile FORCE
 453         $(Q)mkdir -p include/linux include/config
 454         $(Q)$(MAKE) $(build)=scripts/kconfig $@
 455
 456 else
 457 # ===========================================================================
 458 # Build targets only - this includes vmlinux, arch specific targets, clean
 459 # targets and others. In general all targets except *config targets.
 460
 461 ifeq ($(KBUILD_EXTMOD),)
 462 # Additional helpers built in scripts/
 463 # Carefully list dependencies so we do not try to build scripts twice
 464 # in parallel
 465 PHONY += scripts
 466 scripts: scripts_basic include/config/auto.conf
 467         $(Q)$(MAKE) $(build)=$(@)
 468
 469 # Objects we will link into vmlinux / subdirs we need to visit
 470 init-y          := init/
 471 drivers-y       := drivers/ sound/ firmware/
 472 net-y           := net/
 473 libs-y          := lib/
 474 core-y          := usr/
 475 endif # KBUILD_EXTMOD
 476
 477 ifeq ($(dot-config),1)
 478 # Read in config
 479 -include include/config/auto.conf
 480
 481 ifeq ($(KBUILD_EXTMOD),)
 482 # Read in dependencies to all Kconfig* files, make sure to run
 483 # oldconfig if changes are detected.
 484 -include include/config/auto.conf.cmd
 485
 486 # To avoid any implicit rule to kick in, define an empty command
 487 $(KCONFIG_CONFIG) include/config/auto.conf.cmd: ;
 488
 489 # If .config is newer than include/config/auto.conf, someone tinkered
 490 # with it and forgot to run make oldconfig.
 491 # if auto.conf.cmd is missing then we are probably in a cleaned tree so
 492 # we execute the config step to be sure to catch updated Kconfig files
 493 include/config/auto.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd
 494         $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig
 495 else
 496 # external modules needs include/linux/autoconf.h and include/config/auto.conf
 497 # but do not care if they are up-to-date. Use auto.conf to trigger the test
 498 PHONY += include/config/auto.conf
 499
 500 include/config/auto.conf:
 501         $(Q)test -e include/linux/autoconf.h -a -e $@ || (              \
 502         echo;                                                           \
 503         echo "  ERROR: Kernel configuration is invalid.";               \
 504         echo "         include/linux/autoconf.h or $@ are missing.";    \
 505         echo "         Run 'make oldconfig && make prepare' on kernel src to fix it.";  \
 506         echo;                                                           \
 507         /bin/false)
 508
 509 endif # KBUILD_EXTMOD
 510
 511 else
 512 # Dummy target needed, because used as prerequisite
 513 include/config/auto.conf: ;
 514 endif # $(dot-config)
 515
 516 # The all: target is the default when no target is given on the
 517 # command line.
 518 # This allow a user to issue only 'make' to build a kernel including modules
 519 # Defaults vmlinux but it is usually overridden in the arch makefile
 520 all: vmlinux
 521
 522 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 523 KBUILD_CFLAGS   += -Os
 524 else
 525 KBUILD_CFLAGS   += -O2
 526 endif
 527
 528 include $(srctree)/arch/$(SRCARCH)/Makefile
 529
 530 ifneq (CONFIG_FRAME_WARN,0)
 531 KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
 532 endif
 533
 534 # Force gcc to behave correct even for buggy distributions
 535 ifndef CONFIG_CC_STACKPROTECTOR
 536 KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
 537 endif
 538
 539 ifdef CONFIG_FRAME_POINTER
 540 KBUILD_CFLAGS   += -fno-omit-frame-pointer -fno-optimize-sibling-calls
 541 else
 542 KBUILD_CFLAGS   += -fomit-frame-pointer
 543 endif
 544
 545 ifdef CONFIG_DEBUG_INFO
 546 KBUILD_CFLAGS   += -g
 547 KBUILD_AFLAGS   += -gdwarf-2
 548 endif
 549
 550 ifdef CONFIG_FUNCTION_TRACER
 551 KBUILD_CFLAGS   += -pg
 552 endif
 553
 554 # We trigger additional mismatches with less inlining
 555 ifdef CONFIG_DEBUG_SECTION_MISMATCH
 556 KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once)
 557 endif
 558
 559 # arch Makefile may override CC so keep this after arch Makefile is included
 560 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 561 CHECKFLAGS     += $(NOSTDINC_FLAGS)
 562
 563 # warn about C99 declaration after statement
 564 KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
 565
 566 # disable pointer signed / unsigned warnings in gcc 4.0
 567 KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,)
 568
 569 # Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
 570 # But warn user when we do so
 571 warn-assign = \
 572 $(warning "WARNING: Appending $$K$(1) ($(K$(1))) from $(origin K$(1)) to kernel $$$(1)")
 573
 574 ifneq ($(KCPPFLAGS),)
 575         $(call warn-assign,CPPFLAGS)
 576         KBUILD_CPPFLAGS += $(KCPPFLAGS)
 577 endif
 578 ifneq ($(KAFLAGS),)
 579         $(call warn-assign,AFLAGS)
 580         KBUILD_AFLAGS += $(KAFLAGS)
 581 endif
 582 ifneq ($(KCFLAGS),)
 583         $(call warn-assign,CFLAGS)
 584         KBUILD_CFLAGS += $(KCFLAGS)
 585 endif
 586
 587 # Use --build-id when available.
 588 LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
 589                               $(call ld-option, -Wl$(comma)--build-id,))
 590 LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
 591 LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)
 592
 593 # Default kernel image to build when no specific target is given.
 594 # KBUILD_IMAGE may be overruled on the command line or
 595 # set in the environment
 596 # Also any assignments in arch/$(ARCH)/Makefile take precedence over
 597 # this default value
 598 export KBUILD_IMAGE ?= vmlinux
 599
 600 #
 601 # INSTALL_PATH specifies where to place the updated kernel and system map
 602 # images. Default is /boot, but you can set it to other values
 603 export  INSTALL_PATH ?= /boot
 604
 605 #
 606 # INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
 607 # relocations required by build roots.  This is not defined in the
 608 # makefile but the argument can be passed to make if needed.
 609 #
 610
 611 MODLIB  = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
 612 export MODLIB
 613
 614 #
 615 #  INSTALL_MOD_STRIP, if defined, will cause modules to be
 616 #  stripped after they are installed.  If INSTALL_MOD_STRIP is '1', then
 617 #  the default option --strip-debug will be used.  Otherwise,
 618 #  INSTALL_MOD_STRIP will used as the options to the strip command.
 619
 620 ifdef INSTALL_MOD_STRIP
 621 ifeq ($(INSTALL_MOD_STRIP),1)
 622 mod_strip_cmd = $(STRIP) --strip-debug
 623 else
 624 mod_strip_cmd = $(STRIP) $(INSTALL_MOD_STRIP)
 625 endif # INSTALL_MOD_STRIP=1
 626 else
 627 mod_strip_cmd = true
 628 endif # INSTALL_MOD_STRIP
 629 export mod_strip_cmd
 630
 631
 632 ifeq ($(KBUILD_EXTMOD),)
 633 core-y          += kernel/ mm/ fs/ ipc/ security/ crypto/ block/
 634
 635 vmlinux-dirs    := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
 636                      $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
 637                      $(net-y) $(net-m) $(libs-y) $(libs-m)))
 638
 639 vmlinux-alldirs := $(sort $(vmlinux-dirs) $(patsubst %/,%,$(filter %/, \
 640                      $(init-n) $(init-) \
 641                      $(core-n) $(core-) $(drivers-n) $(drivers-) \
 642                      $(net-n)  $(net-)  $(libs-n)    $(libs-))))
 643
 644 init-y          := $(patsubst %/, %/built-in.o, $(init-y))
 645 core-y          := $(patsubst %/, %/built-in.o, $(core-y))
 646 drivers-y       := $(patsubst %/, %/built-in.o, $(drivers-y))
 647 net-y           := $(patsubst %/, %/built-in.o, $(net-y))
 648 libs-y1         := $(patsubst %/, %/lib.a, $(libs-y))
 649 libs-y2         := $(patsubst %/, %/built-in.o, $(libs-y))
 650 libs-y          := $(libs-y1) $(libs-y2)
 651
 652 # Build vmlinux
 653 # ---------------------------------------------------------------------------
 654 # vmlinux is built from the objects selected by $(vmlinux-init) and
 655 # $(vmlinux-main). Most are built-in.o files from top-level directories
 656 # in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
 657 # Ordering when linking is important, and $(vmlinux-init) must be first.
 658 #
 659 # vmlinux
 660 #   ^
 661 #   |
 662 #   +-< $(vmlinux-init)
 663 #   |   +--< init/version.o + more
 664 #   |
 665 #   +--< $(vmlinux-main)
 666 #   |    +--< driver/built-in.o mm/built-in.o + more
 667 #   |
 668 #   +-< kallsyms.o (see description in CONFIG_KALLSYMS section)
 669 #
 670 # vmlinux version (uname -v) cannot be updated during normal
 671 # descending-into-subdirs phase since we do not yet know if we need to
 672 # update vmlinux.
 673 # Therefore this step is delayed until just before final link of vmlinux -
 674 # except in the kallsyms case where it is done just before adding the
 675 # symbols to the kernel.
 676 #
 677 # System.map is generated to document addresses of all kernel symbols
 678
 679 vmlinux-init := $(head-y) $(init-y)
 680 vmlinux-main := $(core-y) $(libs-y) $(drivers-y) $(net-y)
 681 vmlinux-all  := $(vmlinux-init) $(vmlinux-main)
 682 vmlinux-lds  := arch/$(SRCARCH)/kernel/vmlinux.lds
 683 export KBUILD_VMLINUX_OBJS := $(vmlinux-all)
 684
 685 # Rule to link vmlinux - also used during CONFIG_KALLSYMS
 686 # May be overridden by arch/$(ARCH)/Makefile
 687 quiet_cmd_vmlinux__ ?= LD      $@
 688       cmd_vmlinux__ ?= $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) -o $@ \
 689       -T $(vmlinux-lds) $(vmlinux-init)                          \
 690       --start-group $(vmlinux-main) --end-group                  \
 691       $(filter-out $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o FORCE ,$^)
 692
 693 # Generate new vmlinux version
 694 quiet_cmd_vmlinux_version = GEN     .version
 695       cmd_vmlinux_version = set -e;                     \
 696         if [ ! -r .version ]; then                      \
 697           rm -f .version;                               \
 698           echo 1 >.version;                             \
 699         else                                            \
 700           mv .version .old_version;                     \
 701           expr 0$$(cat .old_version) + 1 >.version;     \
 702         fi;                                             \
 703         $(MAKE) $(build)=init
 704
 705 # Generate System.map
 706 quiet_cmd_sysmap = SYSMAP
 707       cmd_sysmap = $(CONFIG_SHELL) $(srctree)/scripts/mksysmap
 708
 709 # Link of vmlinux
 710 # If CONFIG_KALLSYMS is set .version is already updated
 711 # Generate System.map and verify that the content is consistent
 712 # Use + in front of the vmlinux_version rule to silent warning with make -j2
 713 # First command is ':' to allow us to use + in front of the rule
 714 define rule_vmlinux__
 715         :
 716         $(if $(CONFIG_KALLSYMS),,+$(call cmd,vmlinux_version))
 717
 718         $(call cmd,vmlinux__)
 719         $(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
 720
 721         $(Q)$(if $($(quiet)cmd_sysmap),                                      \
 722           echo '  $($(quiet)cmd_sysmap)  System.map' &&)                     \
 723         $(cmd_sysmap) $@ System.map;                                         \
 724         if [ $$? -ne 0 ]; then                                               \
 725                 rm -f $@;                                                    \
 726                 /bin/false;                                                  \
 727         fi;
 728         $(verify_kallsyms)
 729 endef
 730
 731
 732 ifdef CONFIG_KALLSYMS
 733 # Generate section listing all symbols and add it into vmlinux $(kallsyms.o)
 734 # It's a three stage process:
 735 # o .tmp_vmlinux1 has all symbols and sections, but __kallsyms is
 736 #   empty
 737 #   Running kallsyms on that gives us .tmp_kallsyms1.o with
 738 #   the right size - vmlinux version (uname -v) is updated during this step
 739 # o .tmp_vmlinux2 now has a __kallsyms section of the right size,
 740 #   but due to the added section, some addresses have shifted.
 741 #   From here, we generate a correct .tmp_kallsyms2.o
 742 # o The correct .tmp_kallsyms2.o is linked into the final vmlinux.
 743 # o Verify that the System.map from vmlinux matches the map from
 744 #   .tmp_vmlinux2, just in case we did not generate kallsyms correctly.
 745 # o If CONFIG_KALLSYMS_EXTRA_PASS is set, do an extra pass using
 746 #   .tmp_vmlinux3 and .tmp_kallsyms3.o.  This is only meant as a
 747 #   temporary bypass to allow the kernel to be built while the
 748 #   maintainers work out what went wrong with kallsyms.
 749
 750 ifdef CONFIG_KALLSYMS_EXTRA_PASS
 751 last_kallsyms := 3
 752 else
 753 last_kallsyms := 2
 754 endif
 755
 756 kallsyms.o := .tmp_kallsyms$(last_kallsyms).o
 757
 758 define verify_kallsyms
 759         $(Q)$(if $($(quiet)cmd_sysmap),                                      \
 760           echo '  $($(quiet)cmd_sysmap)  .tmp_System.map' &&)                \
 761           $(cmd_sysmap) .tmp_vmlinux$(last_kallsyms) .tmp_System.map
 762         $(Q)cmp -s System.map .tmp_System.map ||                             \
 763                 (echo Inconsistent kallsyms data;                            \
 764                  echo Try setting CONFIG_KALLSYMS_EXTRA_PASS;                \
 765                  rm .tmp_kallsyms* ; /bin/false )
 766 endef
 767
 768 # Update vmlinux version before link
 769 # Use + in front of this rule to silent warning about make -j1
 770 # First command is ':' to allow us to use + in front of this rule
 771 cmd_ksym_ld = $(cmd_vmlinux__)
 772 define rule_ksym_ld
 773         :
 774         +$(call cmd,vmlinux_version)
 775         $(call cmd,vmlinux__)
 776         $(Q)echo 'cmd_$@ := $(cmd_vmlinux__)' > $(@D)/.$(@F).cmd
 777 endef
 778
 779 # Generate .S file with all kernel symbols
 780 quiet_cmd_kallsyms = KSYM    $@
 781       cmd_kallsyms = $(NM) -n $< | $(KALLSYMS) \
 782                      $(if $(CONFIG_KALLSYMS_ALL),--all-symbols) > $@
 783
 784 .tmp_kallsyms1.o .tmp_kallsyms2.o .tmp_kallsyms3.o: %.o: %.S scripts FORCE
 785         $(call if_changed_dep,as_o_S)
 786
 787 .tmp_kallsyms%.S: .tmp_vmlinux% $(KALLSYMS)
 788         $(call cmd,kallsyms)
 789
 790 # .tmp_vmlinux1 must be complete except kallsyms, so update vmlinux version
 791 .tmp_vmlinux1: $(vmlinux-lds) $(vmlinux-all) FORCE
 792         $(call if_changed_rule,ksym_ld)
 793
 794 .tmp_vmlinux2: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms1.o FORCE
 795         $(call if_changed,vmlinux__)
 796
 797 .tmp_vmlinux3: $(vmlinux-lds) $(vmlinux-all) .tmp_kallsyms2.o FORCE
 798         $(call if_changed,vmlinux__)
 799
 800 # Needs to visit scripts/ before $(KALLSYMS) can be used.
 801 $(KALLSYMS): scripts ;
 802
 803 # Generate some data for debugging strange kallsyms problems
 804 debug_kallsyms: .tmp_map$(last_kallsyms)
 805
 806 .tmp_map%: .tmp_vmlinux% FORCE
 807         ($(OBJDUMP) -h $< | $(AWK) '/^ +[0-9]/{print $$4 " 0 " $$2}'; $(NM) $<) | sort > $@
 808
 809 .tmp_map3: .tmp_map2
 810
 811 .tmp_map2: .tmp_map1
 812
 813 endif # ifdef CONFIG_KALLSYMS
 814
 815 # Do modpost on a prelinked vmlinux. The finally linked vmlinux has
 816 # relevant sections renamed as per the linker script.
 817 quiet_cmd_vmlinux-modpost = LD      $@
 818       cmd_vmlinux-modpost = $(LD) $(LDFLAGS) -r -o $@                          \
 819          $(vmlinux-init) --start-group $(vmlinux-main) --end-group             \
 820          $(filter-out $(vmlinux-init) $(vmlinux-main) FORCE ,$^)
 821 define rule_vmlinux-modpost
 822         :
 823         +$(call cmd,vmlinux-modpost)
 824         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost $@
 825         $(Q)echo 'cmd_$@ := $(cmd_vmlinux-modpost)' > $(dot-target).cmd
 826 endef
 827
 828 # vmlinux image - including updated kernel symbols
 829 vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) vmlinux.o $(kallsyms.o) FORCE
 830 ifdef CONFIG_HEADERS_CHECK
 831         $(Q)$(MAKE) -f $(srctree)/Makefile headers_check
 832 endif
 833 ifdef CONFIG_SAMPLES
 834         $(Q)$(MAKE) $(build)=samples
 835 endif
 836 ifdef CONFIG_BUILD_DOCSRC
 837         $(Q)$(MAKE) $(build)=Documentation
 838 endif
 839         $(call vmlinux-modpost)
 840         $(call if_changed_rule,vmlinux__)
 841         $(Q)rm -f .old_version
 842
 843 # build vmlinux.o first to catch section mismatch errors early
 844 ifdef CONFIG_KALLSYMS
 845 .tmp_vmlinux1: vmlinux.o
 846 endif
 847
 848 modpost-init := $(filter-out init/built-in.o, $(vmlinux-init))
 849 vmlinux.o: $(modpost-init) $(vmlinux-main) FORCE
 850         $(call if_changed_rule,vmlinux-modpost)
 851
 852 # The actual objects are generated when descending,
 853 # make sure no implicit rule kicks in
 854 $(sort $(vmlinux-init) $(vmlinux-main)) $(vmlinux-lds): $(vmlinux-dirs) ;
 855
 856 # Handle descending into subdirectories listed in $(vmlinux-dirs)
 857 # Preset locale variables to speed up the build process. Limit locale
 858 # tweaks to this spot to avoid wrong language settings when running
 859 # make menuconfig etc.
 860 # Error messages still appears in the original language
 861
 862 PHONY += $(vmlinux-dirs)
 863 $(vmlinux-dirs): prepare scripts
 864         $(Q)$(MAKE) $(build)=$@
 865
 866 # Build the kernel release string
 867 #
 868 # The KERNELRELEASE value built here is stored in the file
 869 # include/config/kernel.release, and is used when executing several
 870 # make targets, such as "make install" or "make modules_install."
 871 #
 872 # The eventual kernel release string consists of the following fields,
 873 # shown in a hierarchical format to show how smaller parts are concatenated
 874 # to form the larger and final value, with values coming from places like
 875 # the Makefile, kernel config options, make command line options and/or
 876 # SCM tag information.
 877 #
 878 #       $(KERNELVERSION)
 879 #         $(VERSION)                    eg, 2
 880 #         $(PATCHLEVEL)                 eg, 6
 881 #         $(SUBLEVEL)                   eg, 18
 882 #         $(EXTRAVERSION)               eg, -rc6
 883 #       $(localver-full)
 884 #         $(localver)
 885 #           localversion*               (files without backups, containing '~')
 886 #           $(CONFIG_LOCALVERSION)      (from kernel config setting)
 887 #         $(localver-auto)              (only if CONFIG_LOCALVERSION_AUTO is set)
 888 #           ./scripts/setlocalversion   (SCM tag, if one exists)
 889 #           $(LOCALVERSION)             (from make command line if provided)
 890 #
 891 #  Note how the final $(localver-auto) string is included *only* if the
 892 # kernel config option CONFIG_LOCALVERSION_AUTO is selected.  Also, at the
 893 # moment, only git is supported but other SCMs can edit the script
 894 # scripts/setlocalversion and add the appropriate checks as needed.
 895
 896 pattern = ".*/localversion[^~]*"
 897 string  = $(shell cat /dev/null \
 898            `find $(objtree) $(srctree) -maxdepth 1 -regex $(pattern) | sort -u`)
 899
 900 localver = $(subst $(space),, $(string) \
 901                               $(patsubst "%",%,$(CONFIG_LOCALVERSION)))
 902
 903 # If CONFIG_LOCALVERSION_AUTO is set scripts/setlocalversion is called
 904 # and if the SCM is know a tag from the SCM is appended.
 905 # The appended tag is determined by the SCM used.
 906 #
 907 # Currently, only git is supported.
 908 # Other SCMs can edit scripts/setlocalversion and add the appropriate
 909 # checks as needed.
 910 ifdef CONFIG_LOCALVERSION_AUTO
 911         _localver-auto = $(shell $(CONFIG_SHELL) \
 912                           $(srctree)/scripts/setlocalversion $(srctree))
 913         localver-auto  = $(LOCALVERSION)$(_localver-auto)
 914 endif
 915
 916 localver-full = $(localver)$(localver-auto)
 917
 918 # Store (new) KERNELRELASE string in include/config/kernel.release
 919 kernelrelease = $(KERNELVERSION)$(localver-full)
 920 include/config/kernel.release: include/config/auto.conf FORCE
 921         $(Q)rm -f $@
 922         $(Q)echo $(kernelrelease) > $@
 923
 924
 925 # Things we need to do before we recursively start building the kernel
 926 # or the modules are listed in "prepare".
 927 # A multi level approach is used. prepareN is processed before prepareN-1.
 928 # archprepare is used in arch Makefiles and when processed asm symlink,
 929 # version.h and scripts_basic is processed / created.
 930
 931 # Listed in dependency order
 932 PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3
 933
 934 # prepare3 is used to check if we are building in a separate output directory,
 935 # and if so do:
 936 # 1) Check that make has not been executed in the kernel src $(srctree)
 937 # 2) Create the include2 directory, used for the second asm symlink
 938 prepare3: include/config/kernel.release
 939 ifneq ($(KBUILD_SRC),)
 940         @$(kecho) '  Using $(srctree) as source for kernel'
 941         $(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \
 942                 echo "  $(srctree) is not clean, please run 'make mrproper'";\
 943                 echo "  in the '$(srctree)' directory.";\
 944                 /bin/false; \
 945         fi;
 946         $(Q)if [ ! -d include2 ]; then                                  \
 947             mkdir -p include2;                                          \
 948             ln -fsn $(srctree)/include/asm-$(SRCARCH) include2/asm;     \
 949         fi
 950         ln -fsn $(srctree) source
 951 endif
 952
 953 # prepare2 creates a makefile if using a separate output directory
 954 prepare2: prepare3 outputmakefile
 955
 956 prepare1: prepare2 include/linux/version.h include/linux/utsrelease.h \
 957                    include/asm include/config/auto.conf
 958         $(cmd_crmodverdir)
 959
 960 archprepare: prepare1 scripts_basic
 961
 962 prepare0: archprepare FORCE
 963         $(Q)$(MAKE) $(build)=.
 964         $(Q)$(MAKE) $(build)=. missing-syscalls
 965
 966 # All the preparing..
 967 prepare: prepare0
 968
 969 # Leave this as default for preprocessing vmlinux.lds.S, which is now
 970 # done in arch/$(ARCH)/kernel/Makefile
 971
 972 export CPPFLAGS_vmlinux.lds += -P -C -U$(ARCH)
 973
 974 # The asm symlink changes when $(ARCH) changes.
 975 # Detect this and ask user to run make mrproper
 976 # If asm is a stale symlink (point to dir that does not exist) remove it
 977 define check-symlink
 978         set -e;                                                            \
 979         if [ -L include/asm ]; then                                        \
 980                 asmlink=`readlink include/asm | cut -d '-' -f 2`;          \
 981                 if [ "$$asmlink" != "$(SRCARCH)" ]; then                   \
 982                         echo "ERROR: the symlink $@ points to asm-$$asmlink but asm-$(SRCARCH) was expected"; \
 983                         echo "       set ARCH or save .config and run 'make mrproper' to fix it";             \
 984                         exit 1;                                            \
 985                 fi;                                                        \
 986                 test -e $$asmlink || rm include/asm;                       \
 987         elif [ -d include/asm ]; then                                      \
 988                 echo "ERROR: $@ is a directory but a symlink was expected";\
 989                 exit 1;                                                    \
 990         fi
 991 endef
 992
 993 # We create the target directory of the symlink if it does
 994 # not exist so the test in check-symlink works and we have a
 995 # directory for generated filesas used by some architectures.
 996 define create-symlink
 997         if [ ! -L include/asm ]; then                                      \
 998                         $(kecho) '  SYMLINK $@ -> include/asm-$(SRCARCH)'; \
 999                         if [ ! -d include/asm-$(SRCARCH) ]; then           \
1000                                 mkdir -p include/asm-$(SRCARCH);           \
1001                         fi;                                                \
1002                         ln -fsn asm-$(SRCARCH) $@;                         \
1003         fi
1004 endef
1005
1006 include/asm: FORCE
1007         $(Q)$(check-symlink)
1008         $(Q)$(create-symlink)
1009
1010 # Generate some files
1011 # ---------------------------------------------------------------------------
1012
1013 # KERNELRELEASE can change from a few different places, meaning version.h
1014 # needs to be updated, so this check is forced on all builds
1015
1016 uts_len := 64
1017 define filechk_utsrelease.h
1018         if [ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt $(uts_len) ]; then \
1019           echo '"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2;    \
1020           exit 1;                                                         \
1021         fi;                                                               \
1022         (echo \#define UTS_RELEASE \"$(KERNELRELEASE)\";)
1023 endef
1024
1025 define filechk_version.h
1026         (echo \#define LINUX_VERSION_CODE $(shell                             \
1027         expr $(VERSION) \* 65536 + $(PATCHLEVEL) \* 256 + $(SUBLEVEL));     \
1028         echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))';)
1029 endef
1030
1031 include/linux/version.h: $(srctree)/Makefile FORCE
1032         $(call filechk,version.h)
1033
1034 include/linux/utsrelease.h: include/config/kernel.release FORCE
1035         $(call filechk,utsrelease.h)
1036
1037 PHONY += headerdep
1038 headerdep:
1039         $(Q)find include/ -name '*.h' | xargs --max-args 1 scripts/headerdep.pl
1040
1041 # ---------------------------------------------------------------------------
1042
1043 PHONY += depend dep
1044 depend dep:
1045         @echo '*** Warning: make $@ is unnecessary now.'
1046
1047 # ---------------------------------------------------------------------------
1048 # Firmware install
1049 INSTALL_FW_PATH=$(INSTALL_MOD_PATH)/lib/firmware
1050 export INSTALL_FW_PATH
1051
1052 PHONY += firmware_install
1053 firmware_install: FORCE
1054         @mkdir -p $(objtree)/firmware
1055         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_install
1056
1057 # ---------------------------------------------------------------------------
1058 # Kernel headers
1059
1060 #Default location for installed headers
1061 export INSTALL_HDR_PATH = $(objtree)/usr
1062
1063 hdr-inst := -rR -f $(srctree)/scripts/Makefile.headersinst obj
1064 # Find out where the Kbuild file is located to support
1065 # arch/$(ARCH)/include/asm
1066 hdr-dir = $(strip                                                         \
1067           $(if $(wildcard $(srctree)/arch/$(hdr-arch)/include/asm/Kbuild), \
1068                arch/$(hdr-arch)/include/asm, include/asm-$(hdr-arch)))
1069
1070 # If we do an all arch process set dst to asm-$(hdr-arch)
1071 hdr-dst = $(if $(KBUILD_HEADERS), dst=include/asm-$(hdr-arch), dst=include/asm)
1072
1073 PHONY += __headers
1074 __headers: include/linux/version.h scripts_basic FORCE
1075         $(Q)$(MAKE) $(build)=scripts scripts/unifdef
1076
1077 PHONY += headers_install_all
1078 headers_install_all:
1079         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh install
1080
1081 PHONY += headers_install
1082 headers_install: __headers
1083         $(if $(wildcard $(srctree)/$(hdr-dir)/Kbuild),, \
1084         $(error Headers not exportable for the $(SRCARCH) architecture))
1085         $(Q)$(MAKE) $(hdr-inst)=include
1086         $(Q)$(MAKE) $(hdr-inst)=$(hdr-dir) $(hdr-dst)
1087
1088 PHONY += headers_check_all
1089 headers_check_all: headers_install_all
1090         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh check
1091
1092 PHONY += headers_check
1093 headers_check: headers_install
1094         $(Q)$(MAKE) $(hdr-inst)=include HDRCHECK=1
1095         $(Q)$(MAKE) $(hdr-inst)=$(hdr-dir) $(hdr-dst) HDRCHECK=1
1096
1097 # ---------------------------------------------------------------------------
1098 # Modules
1099
1100 ifdef CONFIG_MODULES
1101
1102 # By default, build modules as well
1103
1104 all: modules
1105
1106 #       Build modules
1107 #
1108 #       A module can be listed more than once in obj-m resulting in
1109 #       duplicate lines in modules.order files.  Those are removed
1110 #       using awk while concatenating to the final file.
1111
1112 PHONY += modules
1113 modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux)
1114         $(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order
1115         @$(kecho) '  Building modules, stage 2.';
1116         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1117         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modbuild
1118
1119
1120 # Target to prepare building external modules
1121 PHONY += modules_prepare
1122 modules_prepare: prepare scripts
1123
1124 # Target to install modules
1125 PHONY += modules_install
1126 modules_install: _modinst_ _modinst_post
1127
1128 PHONY += _modinst_
1129 _modinst_:
1130         @if [ -z "`$(DEPMOD) -V 2>/dev/null | grep module-init-tools`" ]; then \
1131                 echo "Warning: you may need to install module-init-tools"; \
1132                 echo "See http://www.codemonkey.org.uk/docs/post-halloween-2.6.txt";\
1133                 sleep 1; \
1134         fi
1135         @rm -rf $(MODLIB)/kernel
1136         @rm -f $(MODLIB)/source
1137         @mkdir -p $(MODLIB)/kernel
1138         @ln -s $(srctree) $(MODLIB)/source
1139         @if [ ! $(objtree) -ef  $(MODLIB)/build ]; then \
1140                 rm -f $(MODLIB)/build ; \
1141                 ln -s $(objtree) $(MODLIB)/build ; \
1142         fi
1143         @cp -f $(objtree)/modules.order $(MODLIB)/
1144         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
1145
1146 # This depmod is only for convenience to give the initial
1147 # boot a modules.dep even before / is mounted read-write.  However the
1148 # boot script depmod is the master version.
1149 PHONY += _modinst_post
1150 _modinst_post: _modinst_
1151         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modinst
1152         $(call cmd,depmod)
1153
1154 else # CONFIG_MODULES
1155
1156 # Modules not configured
1157 # ---------------------------------------------------------------------------
1158
1159 modules modules_install: FORCE
1160         @echo
1161         @echo "The present kernel configuration has modules disabled."
1162         @echo "Type 'make config' and enable loadable module support."
1163         @echo "Then build a kernel with module support enabled."
1164         @echo
1165         @exit 1
1166
1167 endif # CONFIG_MODULES
1168
1169 ###
1170 # Cleaning is done on three levels.
1171 # make clean     Delete most generated files
1172 #                Leave enough to build external modules
1173 # make mrproper  Delete the current configuration, and all generated files
1174 # make distclean Remove editor backup files, patch leftover files and the like
1175
1176 # Directories & files removed with 'make clean'
1177 CLEAN_DIRS  += $(MODVERDIR)
1178 CLEAN_FILES +=  vmlinux System.map \
1179                 .tmp_kallsyms* .tmp_version .tmp_vmlinux* .tmp_System.map
1180
1181 # Directories & files removed with 'make mrproper'
1182 MRPROPER_DIRS  += include/config include2 usr/include
1183 MRPROPER_FILES += .config .config.old include/asm .version .old_version \
1184                   include/linux/autoconf.h include/linux/version.h      \
1185                   include/linux/utsrelease.h                            \
1186                   include/linux/bounds.h include/asm*/asm-offsets.h     \
1187                   Module.symvers Module.markers tags TAGS cscope*
1188
1189 # clean - Delete most, but leave enough to build external modules
1190 #
1191 clean: rm-dirs  := $(CLEAN_DIRS)
1192 clean: rm-files := $(CLEAN_FILES)
1193 clean-dirs      := $(addprefix _clean_,$(srctree) $(vmlinux-alldirs) Documentation)
1194
1195 PHONY += $(clean-dirs) clean archclean
1196 $(clean-dirs):
1197         $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
1198
1199 clean: archclean $(clean-dirs)
1200         $(call cmd,rmdirs)
1201         $(call cmd,rmfiles)
1202         @find . $(RCS_FIND_IGNORE) \
1203                 \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
1204                 -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
1205                 -o -name '*.symtypes' -o -name 'modules.order' \
1206                 -o -name 'Module.markers' -o -name '.tmp_*.o.*' \) \
1207                 -type f -print | xargs rm -f
1208
1209 # mrproper - Delete all generated files, including .config
1210 #
1211 mrproper: rm-dirs  := $(wildcard $(MRPROPER_DIRS))
1212 mrproper: rm-files := $(wildcard $(MRPROPER_FILES))
1213 mrproper-dirs      := $(addprefix _mrproper_,Documentation/DocBook scripts)
1214
1215 PHONY += $(mrproper-dirs) mrproper archmrproper
1216 $(mrproper-dirs):
1217         $(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@)
1218
1219 mrproper: clean archmrproper $(mrproper-dirs)
1220         $(call cmd,rmdirs)
1221         $(call cmd,rmfiles)
1222
1223 # distclean
1224 #
1225 PHONY += distclean
1226
1227 distclean: mrproper
1228         @find $(srctree) $(RCS_FIND_IGNORE) \
1229                 \( -name '*.orig' -o -name '*.rej' -o -name '*~' \
1230                 -o -name '*.bak' -o -name '#*#' -o -name '.*.orig' \
1231                 -o -name '.*.rej' -o -size 0 \
1232                 -o -name '*%' -o -name '.*.cmd' -o -name 'core' \) \
1233                 -type f -print | xargs rm -f
1234
1235
1236 # Packaging of the kernel to various formats
1237 # ---------------------------------------------------------------------------
1238 # rpm target kept for backward compatibility
1239 package-dir     := $(srctree)/scripts/package
1240
1241 %pkg: include/config/kernel.release FORCE
1242         $(Q)$(MAKE) $(build)=$(package-dir) $@
1243 rpm: include/config/kernel.release FORCE
1244         $(Q)$(MAKE) $(build)=$(package-dir) $@
1245
1246
1247 # Brief documentation of the typical targets used
1248 # ---------------------------------------------------------------------------
1249
1250 boards := $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*_defconfig)
1251 boards := $(notdir $(boards))
1252 board-dirs := $(dir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*/*_defconfig))
1253 board-dirs := $(sort $(notdir $(board-dirs:/=)))
1254
1255 help:
1256         @echo  'Cleaning targets:'
1257         @echo  '  clean           - Remove most generated files but keep the config and'
1258         @echo  '                    enough build support to build external modules'
1259         @echo  '  mrproper        - Remove all generated files + config + various backup files'
1260         @echo  '  distclean       - mrproper + remove editor backup and patch files'
1261         @echo  ''
1262         @echo  'Configuration targets:'
1263         @$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
1264         @echo  ''
1265         @echo  'Other generic targets:'
1266         @echo  '  all             - Build all targets marked with [*]'
1267         @echo  '* vmlinux         - Build the bare kernel'
1268         @echo  '* modules         - Build all modules'
1269         @echo  '  modules_install - Install all modules to INSTALL_MOD_PATH (default: /)'
1270         @echo  '  firmware_install- Install all firmware to INSTALL_FW_PATH'
1271         @echo  '                    (default: $$(INSTALL_MOD_PATH)/lib/firmware)'
1272         @echo  '  dir/            - Build all files in dir and below'
1273         @echo  '  dir/file.[ois]  - Build specified target only'
1274         @echo  '  dir/file.ko     - Build module including final link'
1275         @echo  '  prepare         - Set up for building external modules'
1276         @echo  '  tags/TAGS       - Generate tags file for editors'
1277         @echo  '  cscope          - Generate cscope index'
1278         @echo  '  kernelrelease   - Output the release version string'
1279         @echo  '  kernelversion   - Output the version stored in Makefile'
1280         @echo  '  headers_install - Install sanitised kernel headers to INSTALL_HDR_PATH'; \
1281          echo  '                    (default: $(INSTALL_HDR_PATH))'; \
1282          echo  ''
1283         @echo  'Static analysers'
1284         @echo  '  checkstack      - Generate a list of stack hogs'
1285         @echo  '  namespacecheck  - Name space analysis on compiled kernel'
1286         @echo  '  versioncheck    - Sanity check on version.h usage'
1287         @echo  '  includecheck    - Check for duplicate included header files'
1288         @echo  '  export_report   - List the usages of all exported symbols'
1289         @echo  '  headers_check   - Sanity check on exported headers'
1290         @echo  '  headerdep       - Detect inclusion cycles in headers'; \
1291          echo  ''
1292         @echo  'Kernel packaging:'
1293         @$(MAKE) $(build)=$(package-dir) help
1294         @echo  ''
1295         @echo  'Documentation targets:'
1296         @$(MAKE) -f $(srctree)/Documentation/DocBook/Makefile dochelp
1297         @echo  ''
1298         @echo  'Architecture specific targets ($(SRCARCH)):'
1299         @$(if $(archhelp),$(archhelp),\
1300                 echo '  No architecture specific help defined for $(SRCARCH)')
1301         @echo  ''
1302         @$(if $(boards), \
1303                 $(foreach b, $(boards), \
1304                 printf "  %-24s - Build for %s\\n" $(b) $(subst _defconfig,,$(b));) \
1305                 echo '')
1306         @$(if $(board-dirs), \
1307                 $(foreach b, $(board-dirs), \
1308                 printf "  %-16s - Show %s-specific targets\\n" help-$(b) $(b);) \
1309                 printf "  %-16s - Show all of the above\\n" help-boards; \
1310                 echo '')
1311
1312         @echo  '  make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
1313         @echo  '  make V=2   [targets] 2 => give reason for rebuild of target'
1314         @echo  '  make O=dir [targets] Locate all output files in "dir", including .config'
1315         @echo  '  make C=1   [targets] Check all c source with $$CHECK (sparse by default)'
1316         @echo  '  make C=2   [targets] Force check of all c source with $$CHECK'
1317         @echo  ''
1318         @echo  'Execute "make" or "make all" to build all targets marked with [*] '
1319         @echo  'For further info see the ./README file'
1320
1321
1322 help-board-dirs := $(addprefix help-,$(board-dirs))
1323
1324 help-boards: $(help-board-dirs)
1325
1326 boards-per-dir = $(notdir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/$*/*_defconfig))
1327
1328 $(help-board-dirs): help-%:
1329         @echo  'Architecture specific targets ($(SRCARCH) $*):'
1330         @$(if $(boards-per-dir), \
1331                 $(foreach b, $(boards-per-dir), \
1332                 printf "  %-24s - Build for %s\\n" $*/$(b) $(subst _defconfig,,$(b));) \
1333                 echo '')
1334
1335
1336 # Documentation targets
1337 # ---------------------------------------------------------------------------
1338 %docs: scripts_basic FORCE
1339         $(Q)$(MAKE) $(build)=Documentation/DocBook $@
1340
1341 else # KBUILD_EXTMOD
1342
1343 ###
1344 # External module support.
1345 # When building external modules the kernel used as basis is considered
1346 # read-only, and no consistency checks are made and the make
1347 # system is not used on the basis kernel. If updates are required
1348 # in the basis kernel ordinary make commands (without M=...) must
1349 # be used.
1350 #
1351 # The following are the only valid targets when building external
1352 # modules.
1353 # make M=dir clean     Delete all automatically generated files
1354 # make M=dir modules   Make all modules in specified dir
1355 # make M=dir           Same as 'make M=dir modules'
1356 # make M=dir modules_install
1357 #                      Install the modules built in the module directory
1358 #                      Assumes install directory is already created
1359
1360 # We are always building modules
1361 KBUILD_MODULES := 1
1362 PHONY += crmodverdir
1363 crmodverdir:
1364         $(cmd_crmodverdir)
1365
1366 PHONY += $(objtree)/Module.symvers
1367 $(objtree)/Module.symvers:
1368         @test -e $(objtree)/Module.symvers || ( \
1369         echo; \
1370         echo "  WARNING: Symbol version dump $(objtree)/Module.symvers"; \
1371         echo "           is missing; modules will have no dependencies and modversions."; \
1372         echo )
1373
1374 module-dirs := $(addprefix _module_,$(KBUILD_EXTMOD))
1375 PHONY += $(module-dirs) modules
1376 $(module-dirs): crmodverdir $(objtree)/Module.symvers
1377         $(Q)$(MAKE) $(build)=$(patsubst _module_%,%,$@)
1378
1379 modules: $(module-dirs)
1380         @$(kecho) '  Building modules, stage 2.';
1381         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1382
1383 PHONY += modules_install
1384 modules_install: _emodinst_ _emodinst_post
1385
1386 install-dir := $(if $(INSTALL_MOD_DIR),$(INSTALL_MOD_DIR),extra)
1387 PHONY += _emodinst_
1388 _emodinst_:
1389         $(Q)mkdir -p $(MODLIB)/$(install-dir)
1390         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
1391
1392 PHONY += _emodinst_post
1393 _emodinst_post: _emodinst_
1394         $(call cmd,depmod)
1395
1396 clean-dirs := $(addprefix _clean_,$(KBUILD_EXTMOD))
1397
1398 PHONY += $(clean-dirs) clean
1399 $(clean-dirs):
1400         $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
1401
1402 clean:  rm-dirs := $(MODVERDIR)
1403 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
1404 clean: $(clean-dirs)
1405         $(call cmd,rmdirs)
1406         $(call cmd,rmfiles)
1407         @find $(KBUILD_EXTMOD) $(RCS_FIND_IGNORE) \
1408                 \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
1409                 -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \) \
1410                 -type f -print | xargs rm -f
1411
1412 help:
1413         @echo  '  Building external modules.'
1414         @echo  '  Syntax: make -C path/to/kernel/src M=$$PWD target'
1415         @echo  ''
1416         @echo  '  modules         - default target, build the module(s)'
1417         @echo  '  modules_install - install the module'
1418         @echo  '  clean           - remove generated files in module directory only'
1419         @echo  ''
1420
1421 # Dummies...
1422 PHONY += prepare scripts
1423 prepare: ;
1424 scripts: ;
1425 endif # KBUILD_EXTMOD
1426
1427 # Generate tags for editors
1428 # ---------------------------------------------------------------------------
1429 quiet_cmd_tags = GEN     $@
1430       cmd_tags = $(CONFIG_SHELL) $(srctree)/scripts/tags.sh $@
1431
1432 tags TAGS cscope: FORCE
1433         $(call cmd,tags)
1434
1435 # Scripts to check various things for consistency
1436 # ---------------------------------------------------------------------------
1437
1438 includecheck:
1439         find * $(RCS_FIND_IGNORE) \
1440                 -name '*.[hcS]' -type f -print | sort \
1441                 | xargs $(PERL) -w $(srctree)/scripts/checkincludes.pl
1442
1443 versioncheck:
1444         find * $(RCS_FIND_IGNORE) \
1445                 -name '*.[hcS]' -type f -print | sort \
1446                 | xargs $(PERL) -w $(srctree)/scripts/checkversion.pl
1447
1448 namespacecheck:
1449         $(PERL) $(srctree)/scripts/namespace.pl
1450
1451 export_report:
1452         $(PERL) $(srctree)/scripts/export_report.pl
1453
1454 endif #ifeq ($(config-targets),1)
1455 endif #ifeq ($(mixed-targets),1)
1456
1457 PHONY += checkstack kernelrelease kernelversion
1458
1459 # UML needs a little special treatment here.  It wants to use the host
1460 # toolchain, so needs $(SUBARCH) passed to checkstack.pl.  Everyone
1461 # else wants $(ARCH), including people doing cross-builds, which means
1462 # that $(SUBARCH) doesn't work here.
1463 ifeq ($(ARCH), um)
1464 CHECKSTACK_ARCH := $(SUBARCH)
1465 else
1466 CHECKSTACK_ARCH := $(ARCH)
1467 endif
1468 checkstack:
1469         $(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
1470         $(PERL) $(src)/scripts/checkstack.pl $(CHECKSTACK_ARCH)
1471
1472 kernelrelease:
1473         $(if $(wildcard include/config/kernel.release), $(Q)echo $(KERNELRELEASE), \
1474         $(error kernelrelease not valid - run 'make prepare' to update it))
1475 kernelversion:
1476         @echo $(KERNELVERSION)
1477
1478 # Single targets
1479 # ---------------------------------------------------------------------------
1480 # Single targets are compatible with:
1481 # - build with mixed source and output
1482 # - build with separate output dir 'make O=...'
1483 # - external modules
1484 #
1485 #  target-dir => where to store outputfile
1486 #  build-dir  => directory in kernel source tree to use
1487
1488 ifeq ($(KBUILD_EXTMOD),)
1489         build-dir  = $(patsubst %/,%,$(dir $@))
1490         target-dir = $(dir $@)
1491 else
1492         zap-slash=$(filter-out .,$(patsubst %/,%,$(dir $@)))
1493         build-dir  = $(KBUILD_EXTMOD)$(if $(zap-slash),/$(zap-slash))
1494         target-dir = $(if $(KBUILD_EXTMOD),$(dir $<),$(dir $@))
1495 endif
1496
1497 %.s: %.c prepare scripts FORCE
1498         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1499 %.i: %.c prepare scripts FORCE
1500         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1501 %.o: %.c prepare scripts FORCE
1502         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1503 %.lst: %.c prepare scripts FORCE
1504         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1505 %.s: %.S prepare scripts FORCE
1506         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1507 %.o: %.S prepare scripts FORCE
1508         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1509 %.symtypes: %.c prepare scripts FORCE
1510         $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
1511
1512 # Modules
1513 /: prepare scripts FORCE
1514         $(cmd_crmodverdir)
1515         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) \
1516         $(build)=$(build-dir)
1517 %/: prepare scripts FORCE
1518         $(cmd_crmodverdir)
1519         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) \
1520         $(build)=$(build-dir)
1521 %.ko: prepare scripts FORCE
1522         $(cmd_crmodverdir)
1523         $(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1)   \
1524         $(build)=$(build-dir) $(@:.ko=.o)
1525         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
1526
1527 # FIXME Should go into a make.lib or something
1528 # ===========================================================================
1529
1530 quiet_cmd_rmdirs = $(if $(wildcard $(rm-dirs)),CLEAN   $(wildcard $(rm-dirs)))
1531       cmd_rmdirs = rm -rf $(rm-dirs)
1532
1533 quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN   $(wildcard $(rm-files)))
1534       cmd_rmfiles = rm -f $(rm-files)
1535
1536 # Run depmod only if we have System.map and depmod is executable
1537 quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)
1538       cmd_depmod = \
1539         if [ -r System.map -a -x $(DEPMOD) ]; then                              \
1540                 $(DEPMOD) -ae -F System.map                                     \
1541                 $(if $(strip $(INSTALL_MOD_PATH)), -b $(INSTALL_MOD_PATH) -r)   \
1542                 $(KERNELRELEASE);                                               \
1543         fi
1544
1545 # Create temporary dir for module support files
1546 # clean it up only when building all modules
1547 cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
1548                   $(if $(KBUILD_MODULES),; rm -f $(MODVERDIR)/*)
1549
1550 a_flags = -Wp,-MD,$(depfile) $(KBUILD_AFLAGS) $(AFLAGS_KERNEL) \
1551           $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(KBUILD_CPPFLAGS) \
1552           $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(basetarget).o)
1553
1554 quiet_cmd_as_o_S = AS      $@
1555 cmd_as_o_S       = $(CC) $(a_flags) -c -o $@ $<
1556
1557 # read all saved command lines
1558
1559 targets := $(wildcard $(sort $(targets)))
1560 cmd_files := $(wildcard .*.cmd $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
1561
1562 ifneq ($(cmd_files),)
1563   $(cmd_files): ;       # Do not try to update included dependency files
1564   include $(cmd_files)
1565 endif
1566
1567 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=dir
1568 # Usage:
1569 # $(Q)$(MAKE) $(clean)=dir
1570 clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj
1571
1572 endif   # skip-makefile
1573
1574 PHONY += FORCE
1575 FORCE:
1576
1577 # Declare the contents of the .PHONY variable as phony.  We keep that
1578 # information in a variable se we can use it in if_changed and friends.
1579 .PHONY: $(PHONY)