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 # For backward compatibility check that these variables do not change
  40 save-cflags := $(CFLAGS)
  41
  42 # The filename Kbuild has precedence over Makefile
  43 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
  44 kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
  45 include $(kbuild-file)
  46
  47 # If the save-* variables changed error out
  48 ifeq ($(KBUILD_NOPEDANTIC),)
  49         ifneq ("$(save-cflags)","$(CFLAGS)")
  50                 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
  51         endif
  52 endif
  53
  54 include scripts/Makefile.lib
  55
  56 # Do not include host rules unless needed
  57 ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
  58 include scripts/Makefile.host
  59 endif
  60
  61 ifndef obj
  62 $(warning kbuild: Makefile.build is included improperly)
  63 endif
  64
  65 # ===========================================================================
  66
  67 ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
  68 lib-target := $(obj)/lib.a
  69 real-obj-y += $(obj)/lib-ksyms.o
  70 endif
  71
  72 ifneq ($(strip $(real-obj-y) $(need-builtin)),)
  73 builtin-target := $(obj)/built-in.a
  74 endif
  75
  76 modorder-target := $(obj)/modules.order
  77
  78 # We keep a list of all modules in $(MODVERDIR)
  79
  80 __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
  81          $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
  82          $(subdir-ym) $(always)
  83         @:
  84
  85 # Linus' kernel sanity checking tool
  86 ifneq ($(KBUILD_CHECKSRC),0)
  87   ifeq ($(KBUILD_CHECKSRC),2)
  88     quiet_cmd_force_checksrc = CHECK   $<
  89           cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
  90   else
  91       quiet_cmd_checksrc     = CHECK   $<
  92             cmd_checksrc     = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
  93   endif
  94 endif
  95
  96 ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
  97   cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< ;
  98 endif
  99
 100 # Do section mismatch analysis for each module/built-in.a
 101 ifdef CONFIG_DEBUG_SECTION_MISMATCH
 102   cmd_secanalysis = ; scripts/mod/modpost $@
 103 endif
 104
 105 # Compile C sources (.c)
 106 # ---------------------------------------------------------------------------
 107
 108 # Default is built-in, unless we know otherwise
 109 modkern_cflags =                                          \
 110         $(if $(part-of-module),                           \
 111                 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
 112                 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
 113 quiet_modtag := $(empty)   $(empty)
 114
 115 $(real-obj-m)        : part-of-module := y
 116 $(real-obj-m:.o=.i)  : part-of-module := y
 117 $(real-obj-m:.o=.s)  : part-of-module := y
 118 $(real-obj-m:.o=.lst): part-of-module := y
 119
 120 $(real-obj-m)        : quiet_modtag := [M]
 121 $(real-obj-m:.o=.i)  : quiet_modtag := [M]
 122 $(real-obj-m:.o=.s)  : quiet_modtag := [M]
 123 $(real-obj-m:.o=.lst): quiet_modtag := [M]
 124
 125 $(obj-m)             : quiet_modtag := [M]
 126
 127 quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
 128 cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
 129
 130 $(obj)/%.s: $(src)/%.c FORCE
 131         $(call if_changed_dep,cc_s_c)
 132
 133 quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
 134 cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
 135
 136 $(obj)/%.i: $(src)/%.c FORCE
 137         $(call if_changed_dep,cpp_i_c)
 138
 139 # These mirror gensymtypes_S and co below, keep them in synch.
 140 cmd_gensymtypes_c =                                                         \
 141     $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
 142     $(GENKSYMS) $(if $(1), -T $(2))                                         \
 143      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
 144      $(if $(KBUILD_PRESERVE),-p)                                            \
 145      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 146
 147 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
 148 cmd_cc_symtypes_c =                                                         \
 149     set -e;                                                                 \
 150     $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
 151     test -s $@ || rm -f $@
 152
 153 $(obj)/%.symtypes : $(src)/%.c FORCE
 154         $(call cmd,cc_symtypes_c)
 155
 156 # LLVM assembly
 157 # Generate .ll files from .c
 158 quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
 159       cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
 160
 161 $(obj)/%.ll: $(src)/%.c FORCE
 162         $(call if_changed_dep,cc_ll_c)
 163
 164 # C (.c) files
 165 # The C file is compiled and updated dependency information is generated.
 166 # (See cmd_cc_o_c + relevant part of rule_cc_o_c)
 167
 168 quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
 169
 170 ifndef CONFIG_MODVERSIONS
 171 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
 172
 173 else
 174 # When module versioning is enabled the following steps are executed:
 175 # o compile a .tmp_<file>.o from <file>.c
 176 # o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
 177 #   not export symbols, we just rename .tmp_<file>.o to <file>.o and
 178 #   are done.
 179 # o otherwise, we calculate symbol versions using the good old
 180 #   genksyms on the preprocessed source and postprocess them in a way
 181 #   that they are usable as a linker script
 182 # o generate <file>.o from .tmp_<file>.o using the linker to
 183 #   replace the unresolved symbols __crc_exported_symbol with
 184 #   the actual value of the checksum generated by genksyms
 185
 186 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
 187
 188 cmd_modversions_c =                                                             \
 189         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 190                 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 191                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 192                                                                                 \
 193                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
 194                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 195                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 196         else                                                                    \
 197                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 198         fi;
 199 endif
 200
 201 ifdef CONFIG_FTRACE_MCOUNT_RECORD
 202 # gcc 5 supports generating the mcount tables directly
 203 ifneq ($(call cc-option,-mrecord-mcount,y),y)
 204 KBUILD_CFLAGS += -mrecord-mcount
 205 else
 206 # else do it all manually
 207 ifdef BUILD_C_RECORDMCOUNT
 208 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
 209   RECORDMCOUNT_FLAGS = -w
 210 endif
 211 # Due to recursion, we must skip empty.o.
 212 # The empty.o file is created in the make process in order to determine
 213 # the target endianness and word size. It is made before all other C
 214 # files, including recordmcount.
 215 sub_cmd_record_mcount =                                 \
 216         if [ $(@) != "scripts/mod/empty.o" ]; then      \
 217                 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";   \
 218         fi;
 219 recordmcount_source := $(srctree)/scripts/recordmcount.c \
 220                     $(srctree)/scripts/recordmcount.h
 221 else
 222 sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
 223         "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
 224         "$(if $(CONFIG_64BIT),64,32)" \
 225         "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
 226         "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
 227         "$(if $(part-of-module),1,0)" "$(@)";
 228 recordmcount_source := $(srctree)/scripts/recordmcount.pl
 229 endif # BUILD_C_RECORDMCOUNT
 230 cmd_record_mcount =                                             \
 231         if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =   \
 232              "$(CC_FLAGS_FTRACE)" ]; then                       \
 233                 $(sub_cmd_record_mcount)                        \
 234         fi;
 235 endif # -record-mcount
 236 endif # CONFIG_FTRACE_MCOUNT_RECORD
 237
 238 ifdef CONFIG_STACK_VALIDATION
 239 ifneq ($(SKIP_STACK_VALIDATION),1)
 240
 241 __objtool_obj := $(objtree)/tools/objtool/objtool
 242
 243 objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
 244
 245 objtool_args += $(if $(part-of-module), --module,)
 246
 247 ifndef CONFIG_FRAME_POINTER
 248 objtool_args += --no-fp
 249 endif
 250 ifdef CONFIG_GCOV_KERNEL
 251 objtool_args += --no-unreachable
 252 else
 253 objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
 254 endif
 255 ifdef CONFIG_RETPOLINE
 256 ifneq ($(RETPOLINE_CFLAGS),)
 257   objtool_args += --retpoline
 258 endif
 259 endif
 260
 261
 262 ifdef CONFIG_MODVERSIONS
 263 objtool_o = $(@D)/.tmp_$(@F)
 264 else
 265 objtool_o = $(@)
 266 endif
 267
 268 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
 269 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
 270 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
 271 cmd_objtool = $(if $(patsubst y%,, \
 272         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 273         $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
 274 objtool_obj = $(if $(patsubst y%,, \
 275         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 276         $(__objtool_obj))
 277
 278 endif # SKIP_STACK_VALIDATION
 279 endif # CONFIG_STACK_VALIDATION
 280
 281 # Rebuild all objects when objtool changes, or is enabled/disabled.
 282 objtool_dep = $(objtool_obj)                                    \
 283               $(wildcard include/config/orc/unwinder.h          \
 284                          include/config/stack/validation.h)
 285
 286 define rule_cc_o_c
 287         $(call echo-cmd,checksrc) $(cmd_checksrc)                         \
 288         $(call cmd_and_fixdep,cc_o_c)                                     \
 289         $(cmd_checkdoc)                                                   \
 290         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 291         $(cmd_modversions_c)                                              \
 292         $(call echo-cmd,record_mcount) $(cmd_record_mcount)
 293 endef
 294
 295 define rule_as_o_S
 296         $(call cmd_and_fixdep,as_o_S)                                     \
 297         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 298         $(cmd_modversions_S)
 299 endef
 300
 301 # List module undefined symbols (or empty line if not enabled)
 302 ifdef CONFIG_TRIM_UNUSED_KSYMS
 303 cmd_undef_syms = $(NM) $@ | sed -n 's/^  *U //p' | xargs echo
 304 else
 305 cmd_undef_syms = echo
 306 endif
 307
 308 # Built-in and composite module parts
 309 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 310         $(call cmd,force_checksrc)
 311         $(call if_changed_rule,cc_o_c)
 312
 313 # Single-part modules are special since we need to mark them in $(MODVERDIR)
 314
 315 $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 316         $(call cmd,force_checksrc)
 317         $(call if_changed_rule,cc_o_c)
 318         @{ echo $(@:.o=.ko); echo $@; \
 319            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 320
 321 quiet_cmd_cc_lst_c = MKLST   $@
 322       cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
 323                      $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
 324                                      System.map $(OBJDUMP) > $@
 325
 326 $(obj)/%.lst: $(src)/%.c FORCE
 327         $(call if_changed_dep,cc_lst_c)
 328
 329 # Compile assembler sources (.S)
 330 # ---------------------------------------------------------------------------
 331
 332 modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
 333
 334 $(real-obj-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 335 $(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 336
 337 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
 338 # or a file that it includes, in order to get versioned symbols. We build a
 339 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
 340 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
 341 #
 342 # This is convoluted. The .S file must first be preprocessed to run guards and
 343 # expand names, then the resulting exports must be constructed into plain
 344 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
 345 # to make the genksyms input.
 346 #
 347 # These mirror gensymtypes_c and co above, keep them in synch.
 348 cmd_gensymtypes_S =                                                         \
 349     (echo "\#include <linux/kernel.h>" ;                                    \
 350      echo "\#include <asm/asm-prototypes.h>" ;                              \
 351     $(CPP) $(a_flags) $< |                                                  \
 352      grep "\<___EXPORT_SYMBOL\>" |                                          \
 353      sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
 354     $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
 355     $(GENKSYMS) $(if $(1), -T $(2))                                         \
 356      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
 357      $(if $(KBUILD_PRESERVE),-p)                                            \
 358      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 359
 360 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
 361 cmd_cc_symtypes_S =                                                         \
 362     set -e;                                                                 \
 363     $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
 364     test -s $@ || rm -f $@
 365
 366 $(obj)/%.symtypes : $(src)/%.S FORCE
 367         $(call cmd,cc_symtypes_S)
 368
 369
 370 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
 371 cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
 372
 373 $(obj)/%.s: $(src)/%.S FORCE
 374         $(call if_changed_dep,cpp_s_S)
 375
 376 quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
 377
 378 ifndef CONFIG_MODVERSIONS
 379 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 380
 381 else
 382
 383 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
 384
 385 ifeq ($(ASM_PROTOTYPES),)
 386 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 387
 388 else
 389
 390 # versioning matches the C process described above, with difference that
 391 # we parse asm-prototypes.h C header to get function definitions.
 392
 393 cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
 394
 395 cmd_modversions_S =                                                             \
 396         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 397                 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 398                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 399                                                                                 \
 400                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
 401                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 402                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 403         else                                                                    \
 404                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 405         fi;
 406 endif
 407 endif
 408
 409 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
 410         $(call if_changed_rule,as_o_S)
 411
 412 targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
 413 targets += $(extra-y) $(MAKECMDGOALS) $(always)
 414
 415 # Linker scripts preprocessor (.lds.S -> .lds)
 416 # ---------------------------------------------------------------------------
 417 quiet_cmd_cpp_lds_S = LDS     $@
 418       cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
 419                              -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
 420
 421 $(obj)/%.lds: $(src)/%.lds.S FORCE
 422         $(call if_changed_dep,cpp_lds_S)
 423
 424 # ASN.1 grammar
 425 # ---------------------------------------------------------------------------
 426 quiet_cmd_asn1_compiler = ASN.1   $@
 427       cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
 428                                 $(subst .h,.c,$@) $(subst .c,.h,$@)
 429
 430 $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 431         $(call cmd,asn1_compiler)
 432
 433 # Build the compiled-in targets
 434 # ---------------------------------------------------------------------------
 435
 436 # To build objects in subdirs, we need to descend into the directories
 437 $(sort $(subdir-obj-y)): $(subdir-ym) ;
 438
 439 #
 440 # Rule to compile a set of .o files into one .o file
 441 #
 442 ifdef builtin-target
 443
 444 # built-in.a archives are made with no symbol table or index which
 445 # makes them small and fast, but unable to be used by the linker.
 446 # scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol
 447 # table and index.
 448 quiet_cmd_ar_builtin = AR      $@
 449       cmd_ar_builtin = rm -f $@; \
 450                      $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^)
 451
 452 $(builtin-target): $(real-obj-y) FORCE
 453         $(call if_changed,ar_builtin)
 454
 455 targets += $(builtin-target)
 456 endif # builtin-target
 457
 458 #
 459 # Rule to create modules.order file
 460 #
 461 # Create commands to either record .ko file or cat modules.order from
 462 # a subdirectory
 463 modorder-cmds =                                         \
 464         $(foreach m, $(modorder),                       \
 465                 $(if $(filter %/modules.order, $m),     \
 466                         cat $m;, echo kernel/$m;))
 467
 468 $(modorder-target): $(subdir-ym) FORCE
 469         $(Q)(cat /dev/null; $(modorder-cmds)) > $@
 470
 471 #
 472 # Rule to compile a set of .o files into one .a file
 473 #
 474 ifdef lib-target
 475 quiet_cmd_link_l_target = AR      $@
 476
 477 # lib target archives do get a symbol table and index
 478 cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
 479
 480 $(lib-target): $(lib-y) FORCE
 481         $(call if_changed,link_l_target)
 482
 483 targets += $(lib-target)
 484
 485 dummy-object = $(obj)/.lib_exports.o
 486 ksyms-lds = $(dot-target).lds
 487
 488 quiet_cmd_export_list = EXPORTS $@
 489 cmd_export_list = $(OBJDUMP) -h $< | \
 490         sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
 491         rm -f $(dummy-object);\
 492         echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
 493         $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
 494         rm $(dummy-object) $(ksyms-lds)
 495
 496 $(obj)/lib-ksyms.o: $(lib-target) FORCE
 497         $(call if_changed,export_list)
 498
 499 targets += $(obj)/lib-ksyms.o
 500
 501 endif
 502
 503 #
 504 # Rule to link composite objects
 505 #
 506 #  Composite objects are specified in kbuild makefile as follows:
 507 #    <composite-object>-objs := <list of .o files>
 508 #  or
 509 #    <composite-object>-y    := <list of .o files>
 510 #  or
 511 #    <composite-object>-m    := <list of .o files>
 512 #  The -m syntax only works if <composite object> is a module
 513 link_multi_deps =                     \
 514 $(filter $(addprefix $(obj)/,         \
 515 $($(subst $(obj)/,,$(@:.o=-objs)))    \
 516 $($(subst $(obj)/,,$(@:.o=-y)))       \
 517 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
 518
 519 quiet_cmd_link_multi-m = LD [M]  $@
 520 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
 521
 522 $(multi-used-m): FORCE
 523         $(call if_changed,link_multi-m)
 524         @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
 525            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 526 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
 527
 528 targets += $(multi-used-m)
 529 targets := $(filter-out $(PHONY), $(targets))
 530
 531 # Add intermediate targets:
 532 # When building objects with specific suffix patterns, add intermediate
 533 # targets that the final targets are derived from.
 534 intermediate_targets = $(foreach sfx, $(2), \
 535                                 $(patsubst %$(strip $(1)),%$(sfx), \
 536                                         $(filter %$(strip $(1)), $(targets))))
 537 # %.asn1.o <- %.asn1.[ch] <- %.asn1
 538 # %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
 539 # %.lex.o <- %.lex.c <- %.l
 540 # %.tab.o <- %.tab.[ch] <- %.y
 541 targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
 542            $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
 543            $(call intermediate_targets, .lex.o, .lex.c) \
 544            $(call intermediate_targets, .tab.o, .tab.c .tab.h)
 545
 546 # Descending
 547 # ---------------------------------------------------------------------------
 548
 549 PHONY += $(subdir-ym)
 550 $(subdir-ym):
 551         $(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1)
 552
 553 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 554 # ---------------------------------------------------------------------------
 555
 556 PHONY += FORCE
 557
 558 FORCE:
 559
 560 # Read all saved command lines and dependencies for the $(targets) we
 561 # may be building above, using $(if_changed{,_dep}). As an
 562 # optimization, we don't need to read them if the target does not
 563 # exist, we will rebuild anyway in that case.
 564
 565 cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
 566
 567 ifneq ($(cmd_files),)
 568   include $(cmd_files)
 569 endif
 570
 571 ifneq ($(KBUILD_SRC),)
 572 # Create directories for object files if they do not exist
 573 obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
 574 # If cmd_files exist, their directories apparently exist.  Skip mkdir.
 575 exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files))))
 576 obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs)))
 577 ifneq ($(obj-dirs),)
 578 $(shell mkdir -p $(obj-dirs))
 579 endif
 580 endif
 581
 582 # Some files contained in $(targets) are intermediate artifacts.
 583 # We never want them to be removed automatically.
 584 .SECONDARY: $(targets)
 585
 586 .PHONY: $(PHONY)