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