scripts/Makefile.build

   1 # SPDX-License-Identifier: GPL-2.0
   2 # ==========================================================================
   3 # Building
   4 # ==========================================================================
   5
   6 src := $(obj)
   7
   8 PHONY := __build
   9 __build:
  10
  11 # Init all relevant variables used in kbuild files so
  12 # 1) they have correct type
  13 # 2) they do not inherit any value from the environment
  14 obj-y :=
  15 obj-m :=
  16 lib-y :=
  17 lib-m :=
  18 always :=
  19 targets :=
  20 subdir-y :=
  21 subdir-m :=
  22 EXTRA_AFLAGS   :=
  23 EXTRA_CFLAGS   :=
  24 EXTRA_CPPFLAGS :=
  25 EXTRA_LDFLAGS  :=
  26 asflags-y  :=
  27 ccflags-y  :=
  28 cppflags-y :=
  29 ldflags-y  :=
  30
  31 subdir-asflags-y :=
  32 subdir-ccflags-y :=
  33
  34 # Read auto.conf if it exists, otherwise ignore
  35 -include include/config/auto.conf
  36
  37 include scripts/Kbuild.include
  38
  39 # The filename Kbuild has precedence over Makefile
  40 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
  41 kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
  42 include $(kbuild-file)
  43
  44 include scripts/Makefile.lib
  45
  46 # Do not include host rules unless needed
  47 ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
  48 include scripts/Makefile.host
  49 endif
  50
  51 ifndef obj
  52 $(warning kbuild: Makefile.build is included improperly)
  53 endif
  54
  55 # ===========================================================================
  56
  57 ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
  58 lib-target := $(obj)/lib.a
  59 real-obj-y += $(obj)/lib-ksyms.o
  60 endif
  61
  62 ifneq ($(strip $(real-obj-y) $(need-builtin)),)
  63 builtin-target := $(obj)/built-in.a
  64 endif
  65
  66 modorder-target := $(obj)/modules.order
  67
  68 # We keep a list of all modules in $(MODVERDIR)
  69
  70 __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
  71          $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
  72          $(subdir-ym) $(always)
  73         @:
  74
  75 # Linus' kernel sanity checking tool
  76 ifeq ($(KBUILD_CHECKSRC),1)
  77   quiet_cmd_checksrc       = CHECK   $<
  78         cmd_checksrc       = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
  79 else ifeq ($(KBUILD_CHECKSRC),2)
  80   quiet_cmd_force_checksrc = CHECK   $<
  81         cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
  82 endif
  83
  84 ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
  85   cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< ;
  86 endif
  87
  88 # Do section mismatch analysis for each module/built-in.a
  89 ifdef CONFIG_DEBUG_SECTION_MISMATCH
  90   cmd_secanalysis = ; scripts/mod/modpost $@
  91 endif
  92
  93 # Compile C sources (.c)
  94 # ---------------------------------------------------------------------------
  95
  96 # Default is built-in, unless we know otherwise
  97 modkern_cflags =                                          \
  98         $(if $(part-of-module),                           \
  99                 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
 100                 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
 101 quiet_modtag := $(empty)   $(empty)
 102
 103 $(real-obj-m)        : part-of-module := y
 104 $(real-obj-m:.o=.i)  : part-of-module := y
 105 $(real-obj-m:.o=.s)  : part-of-module := y
 106 $(real-obj-m:.o=.lst): part-of-module := y
 107
 108 $(real-obj-m)        : quiet_modtag := [M]
 109 $(real-obj-m:.o=.i)  : quiet_modtag := [M]
 110 $(real-obj-m:.o=.s)  : quiet_modtag := [M]
 111 $(real-obj-m:.o=.lst): quiet_modtag := [M]
 112
 113 $(obj-m)             : quiet_modtag := [M]
 114
 115 quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
 116 cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
 117
 118 $(obj)/%.s: $(src)/%.c FORCE
 119         $(call if_changed_dep,cc_s_c)
 120
 121 quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
 122 cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
 123
 124 $(obj)/%.i: $(src)/%.c FORCE
 125         $(call if_changed_dep,cpp_i_c)
 126
 127 # These mirror gensymtypes_S and co below, keep them in synch.
 128 cmd_gensymtypes_c =                                                         \
 129     $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
 130     $(GENKSYMS) $(if $(1), -T $(2))                                         \
 131      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
 132      $(if $(KBUILD_PRESERVE),-p)                                            \
 133      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 134
 135 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
 136 cmd_cc_symtypes_c =                                                         \
 137     set -e;                                                                 \
 138     $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
 139     test -s $@ || rm -f $@
 140
 141 $(obj)/%.symtypes : $(src)/%.c FORCE
 142         $(call cmd,cc_symtypes_c)
 143
 144 # LLVM assembly
 145 # Generate .ll files from .c
 146 quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
 147       cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
 148
 149 $(obj)/%.ll: $(src)/%.c FORCE
 150         $(call if_changed_dep,cc_ll_c)
 151
 152 # C (.c) files
 153 # The C file is compiled and updated dependency information is generated.
 154 # (See cmd_cc_o_c + relevant part of rule_cc_o_c)
 155
 156 quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
 157
 158 ifndef CONFIG_MODVERSIONS
 159 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
 160
 161 else
 162 # When module versioning is enabled the following steps are executed:
 163 # o compile a .tmp_<file>.o from <file>.c
 164 # o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
 165 #   not export symbols, we just rename .tmp_<file>.o to <file>.o and
 166 #   are done.
 167 # o otherwise, we calculate symbol versions using the good old
 168 #   genksyms on the preprocessed source and postprocess them in a way
 169 #   that they are usable as a linker script
 170 # o generate <file>.o from .tmp_<file>.o using the linker to
 171 #   replace the unresolved symbols __crc_exported_symbol with
 172 #   the actual value of the checksum generated by genksyms
 173
 174 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
 175
 176 cmd_modversions_c =                                                             \
 177         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 178                 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 179                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 180                                                                                 \
 181                 $(LD) $(KBUILD_LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)               \
 182                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 183                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 184         else                                                                    \
 185                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 186         fi;
 187 endif
 188
 189 ifdef CONFIG_FTRACE_MCOUNT_RECORD
 190 ifndef CC_USING_RECORD_MCOUNT
 191 # compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
 192 ifdef BUILD_C_RECORDMCOUNT
 193 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
 194   RECORDMCOUNT_FLAGS = -w
 195 endif
 196 # Due to recursion, we must skip empty.o.
 197 # The empty.o file is created in the make process in order to determine
 198 # the target endianness and word size. It is made before all other C
 199 # files, including recordmcount.
 200 sub_cmd_record_mcount =                                 \
 201         if [ $(@) != "scripts/mod/empty.o" ]; then      \
 202                 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";   \
 203         fi;
 204 recordmcount_source := $(srctree)/scripts/recordmcount.c \
 205                     $(srctree)/scripts/recordmcount.h
 206 else
 207 sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
 208         "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
 209         "$(if $(CONFIG_64BIT),64,32)" \
 210         "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
 211         "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
 212         "$(if $(part-of-module),1,0)" "$(@)";
 213 recordmcount_source := $(srctree)/scripts/recordmcount.pl
 214 endif # BUILD_C_RECORDMCOUNT
 215 cmd_record_mcount =                                             \
 216         if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =   \
 217              "$(CC_FLAGS_FTRACE)" ]; then                       \
 218                 $(sub_cmd_record_mcount)                        \
 219         fi;
 220 endif # CC_USING_RECORD_MCOUNT
 221 endif # CONFIG_FTRACE_MCOUNT_RECORD
 222
 223 ifdef CONFIG_STACK_VALIDATION
 224 ifneq ($(SKIP_STACK_VALIDATION),1)
 225
 226 __objtool_obj := $(objtree)/tools/objtool/objtool
 227
 228 objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
 229
 230 objtool_args += $(if $(part-of-module), --module,)
 231
 232 ifndef CONFIG_FRAME_POINTER
 233 objtool_args += --no-fp
 234 endif
 235 ifdef CONFIG_GCOV_KERNEL
 236 objtool_args += --no-unreachable
 237 endif
 238 ifdef CONFIG_RETPOLINE
 239 ifneq ($(RETPOLINE_CFLAGS),)
 240   objtool_args += --retpoline
 241 endif
 242 endif
 243
 244
 245 ifdef CONFIG_MODVERSIONS
 246 objtool_o = $(@D)/.tmp_$(@F)
 247 else
 248 objtool_o = $(@)
 249 endif
 250
 251 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
 252 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
 253 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
 254 cmd_objtool = $(if $(patsubst y%,, \
 255         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 256         $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
 257 objtool_obj = $(if $(patsubst y%,, \
 258         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 259         $(__objtool_obj))
 260
 261 endif # SKIP_STACK_VALIDATION
 262 endif # CONFIG_STACK_VALIDATION
 263
 264 # Rebuild all objects when objtool changes, or is enabled/disabled.
 265 objtool_dep = $(objtool_obj)                                    \
 266               $(wildcard include/config/orc/unwinder.h          \
 267                          include/config/stack/validation.h)
 268
 269 define rule_cc_o_c
 270         $(call echo-cmd,checksrc) $(cmd_checksrc)                         \
 271         $(call cmd_and_fixdep,cc_o_c)                                     \
 272         $(cmd_checkdoc)                                                   \
 273         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 274         $(cmd_modversions_c)                                              \
 275         $(call echo-cmd,record_mcount) $(cmd_record_mcount)
 276 endef
 277
 278 define rule_as_o_S
 279         $(call cmd_and_fixdep,as_o_S)                                     \
 280         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 281         $(cmd_modversions_S)
 282 endef
 283
 284 # List module undefined symbols (or empty line if not enabled)
 285 ifdef CONFIG_TRIM_UNUSED_KSYMS
 286 cmd_undef_syms = $(NM) $@ | sed -n 's/^  *U //p' | xargs echo
 287 else
 288 cmd_undef_syms = echo
 289 endif
 290
 291 # Built-in and composite module parts
 292 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 293         $(call cmd,force_checksrc)
 294         $(call if_changed_rule,cc_o_c)
 295
 296 # Single-part modules are special since we need to mark them in $(MODVERDIR)
 297
 298 $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 299         $(call cmd,force_checksrc)
 300         $(call if_changed_rule,cc_o_c)
 301         @{ echo $(@:.o=.ko); echo $@; \
 302            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 303
 304 quiet_cmd_cc_lst_c = MKLST   $@
 305       cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
 306                      $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
 307                                      System.map $(OBJDUMP) > $@
 308
 309 $(obj)/%.lst: $(src)/%.c FORCE
 310         $(call if_changed_dep,cc_lst_c)
 311
 312 # Compile assembler sources (.S)
 313 # ---------------------------------------------------------------------------
 314
 315 modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
 316
 317 $(real-obj-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 318 $(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 319
 320 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
 321 # or a file that it includes, in order to get versioned symbols. We build a
 322 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
 323 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
 324 #
 325 # This is convoluted. The .S file must first be preprocessed to run guards and
 326 # expand names, then the resulting exports must be constructed into plain
 327 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
 328 # to make the genksyms input.
 329 #
 330 # These mirror gensymtypes_c and co above, keep them in synch.
 331 cmd_gensymtypes_S =                                                         \
 332     (echo "\#include <linux/kernel.h>" ;                                    \
 333      echo "\#include <asm/asm-prototypes.h>" ;                              \
 334     $(CPP) $(a_flags) $< |                                                  \
 335      grep "\<___EXPORT_SYMBOL\>" |                                          \
 336      sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
 337     $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
 338     $(GENKSYMS) $(if $(1), -T $(2))                                         \
 339      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
 340      $(if $(KBUILD_PRESERVE),-p)                                            \
 341      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 342
 343 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
 344 cmd_cc_symtypes_S =                                                         \
 345     set -e;                                                                 \
 346     $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
 347     test -s $@ || rm -f $@
 348
 349 $(obj)/%.symtypes : $(src)/%.S FORCE
 350         $(call cmd,cc_symtypes_S)
 351
 352
 353 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
 354 cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
 355
 356 $(obj)/%.s: $(src)/%.S FORCE
 357         $(call if_changed_dep,cpp_s_S)
 358
 359 quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
 360
 361 ifndef CONFIG_MODVERSIONS
 362 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 363
 364 else
 365
 366 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
 367
 368 ifeq ($(ASM_PROTOTYPES),)
 369 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 370
 371 else
 372
 373 # versioning matches the C process described above, with difference that
 374 # we parse asm-prototypes.h C header to get function definitions.
 375
 376 cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
 377
 378 cmd_modversions_S =                                                             \
 379         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 380                 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 381                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 382                                                                                 \
 383                 $(LD) $(KBUILD_LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)               \
 384                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 385                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 386         else                                                                    \
 387                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 388         fi;
 389 endif
 390 endif
 391
 392 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
 393         $(call if_changed_rule,as_o_S)
 394
 395 targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
 396 targets += $(extra-y) $(MAKECMDGOALS) $(always)
 397
 398 # Linker scripts preprocessor (.lds.S -> .lds)
 399 # ---------------------------------------------------------------------------
 400 quiet_cmd_cpp_lds_S = LDS     $@
 401       cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
 402                              -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
 403
 404 $(obj)/%.lds: $(src)/%.lds.S FORCE
 405         $(call if_changed_dep,cpp_lds_S)
 406
 407 # ASN.1 grammar
 408 # ---------------------------------------------------------------------------
 409 quiet_cmd_asn1_compiler = ASN.1   $@
 410       cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
 411                                 $(subst .h,.c,$@) $(subst .c,.h,$@)
 412
 413 $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 414         $(call cmd,asn1_compiler)
 415
 416 # Build the compiled-in targets
 417 # ---------------------------------------------------------------------------
 418
 419 # To build objects in subdirs, we need to descend into the directories
 420 $(sort $(subdir-obj-y)): $(subdir-ym) ;
 421
 422 #
 423 # Rule to compile a set of .o files into one .o file
 424 #
 425 ifdef builtin-target
 426
 427 # built-in.a archives are made with no symbol table or index which
 428 # makes them small and fast, but unable to be used by the linker.
 429 # scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol
 430 # table and index.
 431 quiet_cmd_ar_builtin = AR      $@
 432       cmd_ar_builtin = rm -f $@; \
 433                      $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^)
 434
 435 $(builtin-target): $(real-obj-y) FORCE
 436         $(call if_changed,ar_builtin)
 437
 438 targets += $(builtin-target)
 439 endif # builtin-target
 440
 441 #
 442 # Rule to create modules.order file
 443 #
 444 # Create commands to either record .ko file or cat modules.order from
 445 # a subdirectory
 446 modorder-cmds =                                         \
 447         $(foreach m, $(modorder),                       \
 448                 $(if $(filter %/modules.order, $m),     \
 449                         cat $m;, echo kernel/$m;))
 450
 451 $(modorder-target): $(subdir-ym) FORCE
 452         $(Q)(cat /dev/null; $(modorder-cmds)) > $@
 453
 454 #
 455 # Rule to compile a set of .o files into one .a file
 456 #
 457 ifdef lib-target
 458 quiet_cmd_link_l_target = AR      $@
 459
 460 # lib target archives do get a symbol table and index
 461 cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
 462
 463 $(lib-target): $(lib-y) FORCE
 464         $(call if_changed,link_l_target)
 465
 466 targets += $(lib-target)
 467
 468 dummy-object = $(obj)/.lib_exports.o
 469 ksyms-lds = $(dot-target).lds
 470
 471 quiet_cmd_export_list = EXPORTS $@
 472 cmd_export_list = $(OBJDUMP) -h $< | \
 473         sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
 474         rm -f $(dummy-object);\
 475         echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
 476         $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
 477         rm $(dummy-object) $(ksyms-lds)
 478
 479 $(obj)/lib-ksyms.o: $(lib-target) FORCE
 480         $(call if_changed,export_list)
 481
 482 targets += $(obj)/lib-ksyms.o
 483
 484 endif
 485
 486 quiet_cmd_link_multi-m = LD [M]  $@
 487 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) $(cmd_secanalysis)
 488
 489 $(multi-used-m): FORCE
 490         $(call if_changed,link_multi-m)
 491         @{ echo $(@:.o=.ko); echo $(filter %.o,$^); \
 492            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 493 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
 494
 495 targets += $(multi-used-m)
 496 targets := $(filter-out $(PHONY), $(targets))
 497
 498 # Add intermediate targets:
 499 # When building objects with specific suffix patterns, add intermediate
 500 # targets that the final targets are derived from.
 501 intermediate_targets = $(foreach sfx, $(2), \
 502                                 $(patsubst %$(strip $(1)),%$(sfx), \
 503                                         $(filter %$(strip $(1)), $(targets))))
 504 # %.asn1.o <- %.asn1.[ch] <- %.asn1
 505 # %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
 506 # %.lex.o <- %.lex.c <- %.l
 507 # %.tab.o <- %.tab.[ch] <- %.y
 508 targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
 509            $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
 510            $(call intermediate_targets, .lex.o, .lex.c) \
 511            $(call intermediate_targets, .tab.o, .tab.c .tab.h)
 512
 513 # Descending
 514 # ---------------------------------------------------------------------------
 515
 516 PHONY += $(subdir-ym)
 517 $(subdir-ym):
 518         $(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1)
 519
 520 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 521 # ---------------------------------------------------------------------------
 522
 523 PHONY += FORCE
 524
 525 FORCE:
 526
 527 # Read all saved command lines and dependencies for the $(targets) we
 528 # may be building above, using $(if_changed{,_dep}). As an
 529 # optimization, we don't need to read them if the target does not
 530 # exist, we will rebuild anyway in that case.
 531
 532 cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
 533
 534 ifneq ($(cmd_files),)
 535   include $(cmd_files)
 536 endif
 537
 538 ifneq ($(KBUILD_SRC),)
 539 # Create directories for object files if they do not exist
 540 obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
 541 # If cmd_files exist, their directories apparently exist.  Skip mkdir.
 542 exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files))))
 543 obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs)))
 544 ifneq ($(obj-dirs),)
 545 $(shell mkdir -p $(obj-dirs))
 546 endif
 547 endif
 548
 549 # Some files contained in $(targets) are intermediate artifacts.
 550 # We never want them to be removed automatically.
 551 .SECONDARY: $(targets)
 552
 553 .PHONY: $(PHONY)