linux/scripts/Makefile.build
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   1# ==========================================================================
   2# Building
   3# ==========================================================================
   4
   5src := $(obj)
   6
   7PHONY := __build
   8__build:
   9
  10# Init all relevant variables used in kbuild files so
  11# 1) they have correct type
  12# 2) they do not inherit any value from the environment
  13obj-y :=
  14obj-m :=
  15lib-y :=
  16lib-m :=
  17always :=
  18targets :=
  19subdir-y :=
  20subdir-m :=
  21EXTRA_AFLAGS   :=
  22EXTRA_CFLAGS   :=
  23EXTRA_CPPFLAGS :=
  24EXTRA_LDFLAGS  :=
  25asflags-y  :=
  26ccflags-y  :=
  27cppflags-y :=
  28ldflags-y  :=
  29
  30subdir-asflags-y :=
  31subdir-ccflags-y :=
  32
  33# Read auto.conf if it exists, otherwise ignore
  34-include include/config/auto.conf
  35
  36include scripts/Kbuild.include
  37
  38# For backward compatibility check that these variables do not change
  39save-cflags := $(CFLAGS)
  40
  41# The filename Kbuild has precedence over Makefile
  42kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
  43kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
  44include $(kbuild-file)
  45
  46# If the save-* variables changed error out
  47ifeq ($(KBUILD_NOPEDANTIC),)
  48        ifneq ("$(save-cflags)","$(CFLAGS)")
  49                $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
  50        endif
  51endif
  52
  53#
  54# make W=... settings
  55#
  56# W=1 - warnings that may be relevant and does not occur too often
  57# W=2 - warnings that occur quite often but may still be relevant
  58# W=3 - the more obscure warnings, can most likely be ignored
  59#
  60# $(call cc-option, -W...) handles gcc -W.. options which
  61# are not supported by all versions of the compiler
  62ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS
  63warning-  := $(empty)
  64
  65warning-1 := -Wextra -Wunused -Wno-unused-parameter
  66warning-1 += -Wmissing-declarations
  67warning-1 += -Wmissing-format-attribute
  68warning-1 += -Wmissing-prototypes
  69warning-1 += -Wold-style-definition
  70warning-1 += $(call cc-option, -Wmissing-include-dirs)
  71warning-1 += $(call cc-option, -Wunused-but-set-variable)
  72warning-1 += $(call cc-disable-warning, missing-field-initializers)
  73
  74warning-2 := -Waggregate-return
  75warning-2 += -Wcast-align
  76warning-2 += -Wdisabled-optimization
  77warning-2 += -Wnested-externs
  78warning-2 += -Wshadow
  79warning-2 += $(call cc-option, -Wlogical-op)
  80warning-2 += $(call cc-option, -Wmissing-field-initializers)
  81
  82warning-3 := -Wbad-function-cast
  83warning-3 += -Wcast-qual
  84warning-3 += -Wconversion
  85warning-3 += -Wpacked
  86warning-3 += -Wpadded
  87warning-3 += -Wpointer-arith
  88warning-3 += -Wredundant-decls
  89warning-3 += -Wswitch-default
  90warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
  91warning-3 += $(call cc-option, -Wvla)
  92
  93warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
  94warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
  95warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
  96
  97ifeq ("$(strip $(warning))","")
  98        $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
  99endif
 100
 101KBUILD_CFLAGS += $(warning)
 102endif
 103
 104include scripts/Makefile.lib
 105
 106ifdef host-progs
 107ifneq ($(hostprogs-y),$(host-progs))
 108$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
 109hostprogs-y += $(host-progs)
 110endif
 111endif
 112
 113# Do not include host rules unless needed
 114ifneq ($(hostprogs-y)$(hostprogs-m),)
 115include scripts/Makefile.host
 116endif
 117
 118ifneq ($(KBUILD_SRC),)
 119# Create output directory if not already present
 120_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
 121
 122# Create directories for object files if directory does not exist
 123# Needed when obj-y := dir/file.o syntax is used
 124_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
 125endif
 126
 127ifndef obj
 128$(warning kbuild: Makefile.build is included improperly)
 129endif
 130
 131# ===========================================================================
 132
 133ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),)
 134lib-target := $(obj)/lib.a
 135endif
 136
 137ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(subdir-m) $(lib-target)),)
 138builtin-target := $(obj)/built-in.o
 139endif
 140
 141modorder-target := $(obj)/modules.order
 142
 143# We keep a list of all modules in $(MODVERDIR)
 144
 145__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
 146         $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
 147         $(subdir-ym) $(always)
 148        @:
 149
 150# Linus' kernel sanity checking tool
 151ifneq ($(KBUILD_CHECKSRC),0)
 152  ifeq ($(KBUILD_CHECKSRC),2)
 153    quiet_cmd_force_checksrc = CHECK   $<
 154          cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
 155  else
 156      quiet_cmd_checksrc     = CHECK   $<
 157            cmd_checksrc     = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
 158  endif
 159endif
 160
 161# Do section mismatch analysis for each module/built-in.o
 162ifdef CONFIG_DEBUG_SECTION_MISMATCH
 163  cmd_secanalysis = ; scripts/mod/modpost $@
 164endif
 165
 166# Compile C sources (.c)
 167# ---------------------------------------------------------------------------
 168
 169# Default is built-in, unless we know otherwise
 170modkern_cflags =                                          \
 171        $(if $(part-of-module),                           \
 172                $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
 173                $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
 174quiet_modtag := $(empty)   $(empty)
 175
 176$(real-objs-m)        : part-of-module := y
 177$(real-objs-m:.o=.i)  : part-of-module := y
 178$(real-objs-m:.o=.s)  : part-of-module := y
 179$(real-objs-m:.o=.lst): part-of-module := y
 180
 181$(real-objs-m)        : quiet_modtag := [M]
 182$(real-objs-m:.o=.i)  : quiet_modtag := [M]
 183$(real-objs-m:.o=.s)  : quiet_modtag := [M]
 184$(real-objs-m:.o=.lst): quiet_modtag := [M]
 185
 186$(obj-m)              : quiet_modtag := [M]
 187
 188# Default for not multi-part modules
 189modname = $(basetarget)
 190
 191$(multi-objs-m)         : modname = $(modname-multi)
 192$(multi-objs-m:.o=.i)   : modname = $(modname-multi)
 193$(multi-objs-m:.o=.s)   : modname = $(modname-multi)
 194$(multi-objs-m:.o=.lst) : modname = $(modname-multi)
 195$(multi-objs-y)         : modname = $(modname-multi)
 196$(multi-objs-y:.o=.i)   : modname = $(modname-multi)
 197$(multi-objs-y:.o=.s)   : modname = $(modname-multi)
 198$(multi-objs-y:.o=.lst) : modname = $(modname-multi)
 199
 200quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
 201cmd_cc_s_c       = $(CC) $(c_flags) -fverbose-asm -S -o $@ $<
 202
 203$(obj)/%.s: $(src)/%.c FORCE
 204        $(call if_changed_dep,cc_s_c)
 205
 206quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@
 207cmd_cc_i_c       = $(CPP) $(c_flags)   -o $@ $<
 208
 209$(obj)/%.i: $(src)/%.c FORCE
 210        $(call if_changed_dep,cc_i_c)
 211
 212cmd_gensymtypes =                                                           \
 213    $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
 214    $(GENKSYMS) $(if $(1), -T $(2)) -a $(ARCH)                              \
 215     $(if $(KBUILD_PRESERVE),-p)                                            \
 216     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 217
 218quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
 219cmd_cc_symtypes_c =                                                         \
 220    set -e;                                                                 \
 221    $(call cmd_gensymtypes,true,$@) >/dev/null;                             \
 222    test -s $@ || rm -f $@
 223
 224$(obj)/%.symtypes : $(src)/%.c FORCE
 225        $(call cmd,cc_symtypes_c)
 226
 227# C (.c) files
 228# The C file is compiled and updated dependency information is generated.
 229# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
 230
 231quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
 232
 233ifndef CONFIG_MODVERSIONS
 234cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
 235
 236else
 237# When module versioning is enabled the following steps are executed:
 238# o compile a .tmp_<file>.o from <file>.c
 239# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
 240#   not export symbols, we just rename .tmp_<file>.o to <file>.o and
 241#   are done.
 242# o otherwise, we calculate symbol versions using the good old
 243#   genksyms on the preprocessed source and postprocess them in a way
 244#   that they are usable as a linker script
 245# o generate <file>.o from .tmp_<file>.o using the linker to
 246#   replace the unresolved symbols __crc_exported_symbol with
 247#   the actual value of the checksum generated by genksyms
 248
 249cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
 250cmd_modversions =                                                               \
 251        if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 252                $(call cmd_gensymtypes,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))    \
 253                    > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 254                                                                                \
 255                $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
 256                        -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 257                rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 258        else                                                                    \
 259                mv -f $(@D)/.tmp_$(@F) $@;                                      \
 260        fi;
 261endif
 262
 263ifdef CONFIG_FTRACE_MCOUNT_RECORD
 264ifdef BUILD_C_RECORDMCOUNT
 265ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
 266  RECORDMCOUNT_FLAGS = -w
 267endif
 268# Due to recursion, we must skip empty.o.
 269# The empty.o file is created in the make process in order to determine
 270#  the target endianness and word size. It is made before all other C
 271#  files, including recordmcount.
 272sub_cmd_record_mcount =                                 \
 273        if [ $(@) != "scripts/mod/empty.o" ]; then      \
 274                $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";   \
 275        fi;
 276recordmcount_source := $(srctree)/scripts/recordmcount.c \
 277                    $(srctree)/scripts/recordmcount.h
 278else
 279sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
 280        "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
 281        "$(if $(CONFIG_64BIT),64,32)" \
 282        "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
 283        "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
 284        "$(if $(part-of-module),1,0)" "$(@)";
 285recordmcount_source := $(srctree)/scripts/recordmcount.pl
 286endif
 287cmd_record_mcount =                                             \
 288        if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then    \
 289                $(sub_cmd_record_mcount)                        \
 290        fi;
 291endif
 292
 293define rule_cc_o_c
 294        $(call echo-cmd,checksrc) $(cmd_checksrc)                         \
 295        $(call echo-cmd,cc_o_c) $(cmd_cc_o_c);                            \
 296        $(cmd_modversions)                                                \
 297        $(call echo-cmd,record_mcount)                                    \
 298        $(cmd_record_mcount)                                              \
 299        scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
 300                                                      $(dot-target).tmp;  \
 301        rm -f $(depfile);                                                 \
 302        mv -f $(dot-target).tmp $(dot-target).cmd
 303endef
 304
 305# Built-in and composite module parts
 306$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
 307        $(call cmd,force_checksrc)
 308        $(call if_changed_rule,cc_o_c)
 309
 310# Single-part modules are special since we need to mark them in $(MODVERDIR)
 311
 312$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
 313        $(call cmd,force_checksrc)
 314        $(call if_changed_rule,cc_o_c)
 315        @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod)
 316
 317quiet_cmd_cc_lst_c = MKLST   $@
 318      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
 319                     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
 320                                     System.map $(OBJDUMP) > $@
 321
 322$(obj)/%.lst: $(src)/%.c FORCE
 323        $(call if_changed_dep,cc_lst_c)
 324
 325# Compile assembler sources (.S)
 326# ---------------------------------------------------------------------------
 327
 328modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
 329
 330$(real-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 331$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 332
 333quiet_cmd_as_s_S = CPP $(quiet_modtag) $@
 334cmd_as_s_S       = $(CPP) $(a_flags)   -o $@ $< 
 335
 336$(obj)/%.s: $(src)/%.S FORCE
 337        $(call if_changed_dep,as_s_S)
 338
 339quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
 340cmd_as_o_S       = $(CC) $(a_flags) -c -o $@ $<
 341
 342$(obj)/%.o: $(src)/%.S FORCE
 343        $(call if_changed_dep,as_o_S)
 344
 345targets += $(real-objs-y) $(real-objs-m) $(lib-y)
 346targets += $(extra-y) $(MAKECMDGOALS) $(always)
 347
 348# Linker scripts preprocessor (.lds.S -> .lds)
 349# ---------------------------------------------------------------------------
 350quiet_cmd_cpp_lds_S = LDS     $@
 351      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
 352                             -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
 353
 354$(obj)/%.lds: $(src)/%.lds.S FORCE
 355        $(call if_changed_dep,cpp_lds_S)
 356
 357# Build the compiled-in targets
 358# ---------------------------------------------------------------------------
 359
 360# To build objects in subdirs, we need to descend into the directories
 361$(sort $(subdir-obj-y)): $(subdir-ym) ;
 362
 363#
 364# Rule to compile a set of .o files into one .o file
 365#
 366ifdef builtin-target
 367quiet_cmd_link_o_target = LD      $@
 368# If the list of objects to link is empty, just create an empty built-in.o
 369cmd_link_o_target = $(if $(strip $(obj-y)),\
 370                      $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \
 371                      $(cmd_secanalysis),\
 372                      rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@)
 373
 374$(builtin-target): $(obj-y) FORCE
 375        $(call if_changed,link_o_target)
 376
 377targets += $(builtin-target)
 378endif # builtin-target
 379
 380#
 381# Rule to create modules.order file
 382#
 383# Create commands to either record .ko file or cat modules.order from
 384# a subdirectory
 385modorder-cmds =                                         \
 386        $(foreach m, $(modorder),                       \
 387                $(if $(filter %/modules.order, $m),     \
 388                        cat $m;, echo kernel/$m;))
 389
 390$(modorder-target): $(subdir-ym) FORCE
 391        $(Q)(cat /dev/null; $(modorder-cmds)) > $@
 392
 393#
 394# Rule to compile a set of .o files into one .a file
 395#
 396ifdef lib-target
 397quiet_cmd_link_l_target = AR      $@
 398cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
 399
 400$(lib-target): $(lib-y) FORCE
 401        $(call if_changed,link_l_target)
 402
 403targets += $(lib-target)
 404endif
 405
 406#
 407# Rule to link composite objects
 408#
 409#  Composite objects are specified in kbuild makefile as follows:
 410#    <composite-object>-objs := <list of .o files>
 411#  or
 412#    <composite-object>-y    := <list of .o files>
 413link_multi_deps =                     \
 414$(filter $(addprefix $(obj)/,         \
 415$($(subst $(obj)/,,$(@:.o=-objs)))    \
 416$($(subst $(obj)/,,$(@:.o=-y)))), $^)
 417 
 418quiet_cmd_link_multi-y = LD      $@
 419cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
 420
 421quiet_cmd_link_multi-m = LD [M]  $@
 422cmd_link_multi-m = $(cmd_link_multi-y)
 423
 424# We would rather have a list of rules like
 425#       foo.o: $(foo-objs)
 426# but that's not so easy, so we rather make all composite objects depend
 427# on the set of all their parts
 428$(multi-used-y) : %.o: $(multi-objs-y) FORCE
 429        $(call if_changed,link_multi-y)
 430
 431$(multi-used-m) : %.o: $(multi-objs-m) FORCE
 432        $(call if_changed,link_multi-m)
 433        @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod)
 434
 435targets += $(multi-used-y) $(multi-used-m)
 436
 437
 438# Descending
 439# ---------------------------------------------------------------------------
 440
 441PHONY += $(subdir-ym)
 442$(subdir-ym):
 443        $(Q)$(MAKE) $(build)=$@
 444
 445# Add FORCE to the prequisites of a target to force it to be always rebuilt.
 446# ---------------------------------------------------------------------------
 447
 448PHONY += FORCE
 449
 450FORCE:
 451
 452# Read all saved command lines and dependencies for the $(targets) we
 453# may be building above, using $(if_changed{,_dep}). As an
 454# optimization, we don't need to read them if the target does not
 455# exist, we will rebuild anyway in that case.
 456
 457targets := $(wildcard $(sort $(targets)))
 458cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
 459
 460ifneq ($(cmd_files),)
 461  include $(cmd_files)
 462endif
 463
 464# Declare the contents of the .PHONY variable as phony.  We keep that
 465# information in a variable se we can use it in if_changed and friends.
 466
 467.PHONY: $(PHONY)
 468
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