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 ifdef host-progs
  57 ifneq ($(hostprogs-y),$(host-progs))
  58 $(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
  59 hostprogs-y += $(host-progs)
  60 endif
  61 endif
  62
  63 # Do not include host rules unless needed
  64 ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
  65 include scripts/Makefile.host
  66 endif
  67
  68 ifndef obj
  69 $(warning kbuild: Makefile.build is included improperly)
  70 endif
  71
  72 # ===========================================================================
  73
  74 ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
  75 lib-target := $(obj)/lib.a
  76 real-obj-y += $(obj)/lib-ksyms.o
  77 endif
  78
  79 ifneq ($(strip $(real-obj-y) $(need-builtin)),)
  80 builtin-target := $(obj)/built-in.a
  81 endif
  82
  83 modorder-target := $(obj)/modules.order
  84
  85 # We keep a list of all modules in $(MODVERDIR)
  86
  87 __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
  88          $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
  89          $(subdir-ym) $(always)
  90         @:
  91
  92 # Linus' kernel sanity checking tool
  93 ifneq ($(KBUILD_CHECKSRC),0)
  94   ifeq ($(KBUILD_CHECKSRC),2)
  95     quiet_cmd_force_checksrc = CHECK   $<
  96           cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
  97   else
  98       quiet_cmd_checksrc     = CHECK   $<
  99             cmd_checksrc     = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
 100   endif
 101 endif
 102
 103 ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
 104   cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< ;
 105 endif
 106
 107 # Do section mismatch analysis for each module/built-in.a
 108 ifdef CONFIG_DEBUG_SECTION_MISMATCH
 109   cmd_secanalysis = ; scripts/mod/modpost $@
 110 endif
 111
 112 # Compile C sources (.c)
 113 # ---------------------------------------------------------------------------
 114
 115 # Default is built-in, unless we know otherwise
 116 modkern_cflags =                                          \
 117         $(if $(part-of-module),                           \
 118                 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
 119                 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
 120 quiet_modtag := $(empty)   $(empty)
 121
 122 $(real-obj-m)        : part-of-module := y
 123 $(real-obj-m:.o=.i)  : part-of-module := y
 124 $(real-obj-m:.o=.s)  : part-of-module := y
 125 $(real-obj-m:.o=.lst): part-of-module := y
 126
 127 $(real-obj-m)        : quiet_modtag := [M]
 128 $(real-obj-m:.o=.i)  : quiet_modtag := [M]
 129 $(real-obj-m:.o=.s)  : quiet_modtag := [M]
 130 $(real-obj-m:.o=.lst): quiet_modtag := [M]
 131
 132 $(obj-m)             : quiet_modtag := [M]
 133
 134 quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
 135 cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
 136
 137 $(obj)/%.s: $(src)/%.c FORCE
 138         $(call if_changed_dep,cc_s_c)
 139
 140 quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
 141 cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
 142
 143 $(obj)/%.i: $(src)/%.c FORCE
 144         $(call if_changed_dep,cpp_i_c)
 145
 146 # These mirror gensymtypes_S and co below, keep them in synch.
 147 cmd_gensymtypes_c =                                                         \
 148     $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
 149     $(GENKSYMS) $(if $(1), -T $(2))                                         \
 150      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
 151      $(if $(KBUILD_PRESERVE),-p)                                            \
 152      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 153
 154 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
 155 cmd_cc_symtypes_c =                                                         \
 156     set -e;                                                                 \
 157     $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
 158     test -s $@ || rm -f $@
 159
 160 $(obj)/%.symtypes : $(src)/%.c FORCE
 161         $(call cmd,cc_symtypes_c)
 162
 163 # LLVM assembly
 164 # Generate .ll files from .c
 165 quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
 166       cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
 167
 168 $(obj)/%.ll: $(src)/%.c FORCE
 169         $(call if_changed_dep,cc_ll_c)
 170
 171 # C (.c) files
 172 # The C file is compiled and updated dependency information is generated.
 173 # (See cmd_cc_o_c + relevant part of rule_cc_o_c)
 174
 175 quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
 176
 177 ifndef CONFIG_MODVERSIONS
 178 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
 179
 180 else
 181 # When module versioning is enabled the following steps are executed:
 182 # o compile a .tmp_<file>.o from <file>.c
 183 # o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
 184 #   not export symbols, we just rename .tmp_<file>.o to <file>.o and
 185 #   are done.
 186 # o otherwise, we calculate symbol versions using the good old
 187 #   genksyms on the preprocessed source and postprocess them in a way
 188 #   that they are usable as a linker script
 189 # o generate <file>.o from .tmp_<file>.o using the linker to
 190 #   replace the unresolved symbols __crc_exported_symbol with
 191 #   the actual value of the checksum generated by genksyms
 192
 193 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
 194
 195 cmd_modversions_c =                                                             \
 196         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 197                 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 198                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 199                                                                                 \
 200                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
 201                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 202                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 203         else                                                                    \
 204                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 205         fi;
 206 endif
 207
 208 ifdef CONFIG_FTRACE_MCOUNT_RECORD
 209 # gcc 5 supports generating the mcount tables directly
 210 ifneq ($(call cc-option,-mrecord-mcount,y),y)
 211 KBUILD_CFLAGS += -mrecord-mcount
 212 else
 213 # else do it all manually
 214 ifdef BUILD_C_RECORDMCOUNT
 215 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
 216   RECORDMCOUNT_FLAGS = -w
 217 endif
 218 # Due to recursion, we must skip empty.o.
 219 # The empty.o file is created in the make process in order to determine
 220 # the target endianness and word size. It is made before all other C
 221 # files, including recordmcount.
 222 sub_cmd_record_mcount =                                 \
 223         if [ $(@) != "scripts/mod/empty.o" ]; then      \
 224                 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";   \
 225         fi;
 226 recordmcount_source := $(srctree)/scripts/recordmcount.c \
 227                     $(srctree)/scripts/recordmcount.h
 228 else
 229 sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
 230         "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
 231         "$(if $(CONFIG_64BIT),64,32)" \
 232         "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
 233         "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
 234         "$(if $(part-of-module),1,0)" "$(@)";
 235 recordmcount_source := $(srctree)/scripts/recordmcount.pl
 236 endif # BUILD_C_RECORDMCOUNT
 237 cmd_record_mcount =                                             \
 238         if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =   \
 239              "$(CC_FLAGS_FTRACE)" ]; then                       \
 240                 $(sub_cmd_record_mcount)                        \
 241         fi;
 242 endif # CONFIG_FTRACE_MCOUNT_RECORD
 243
 244 ifdef CONFIG_STACK_VALIDATION
 245 ifneq ($(SKIP_STACK_VALIDATION),1)
 246
 247 __objtool_obj := $(objtree)/tools/objtool/objtool
 248
 249 objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
 250
 251 objtool_args += $(if $(part-of-module), --module,)
 252
 253 ifndef CONFIG_FRAME_POINTER
 254 objtool_args += --no-fp
 255 endif
 256 ifdef CONFIG_GCOV_KERNEL
 257 objtool_args += --no-unreachable
 258 else
 259 objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
 260 endif
 261 ifdef CONFIG_RETPOLINE
 262 ifneq ($(RETPOLINE_CFLAGS),)
 263   objtool_args += --retpoline
 264 endif
 265 endif
 266 endif
 267
 268
 269 ifdef CONFIG_MODVERSIONS
 270 objtool_o = $(@D)/.tmp_$(@F)
 271 else
 272 objtool_o = $(@)
 273 endif
 274
 275 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
 276 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
 277 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
 278 cmd_objtool = $(if $(patsubst y%,, \
 279         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 280         $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
 281 objtool_obj = $(if $(patsubst y%,, \
 282         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 283         $(__objtool_obj))
 284
 285 endif # SKIP_STACK_VALIDATION
 286 endif # CONFIG_STACK_VALIDATION
 287
 288 # Rebuild all objects when objtool changes, or is enabled/disabled.
 289 objtool_dep = $(objtool_obj)                                    \
 290               $(wildcard include/config/orc/unwinder.h          \
 291                          include/config/stack/validation.h)
 292
 293 define rule_cc_o_c
 294         $(call echo-cmd,checksrc) $(cmd_checksrc)                         \
 295         $(call cmd_and_fixdep,cc_o_c)                                     \
 296         $(cmd_checkdoc)                                                   \
 297         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 298         $(cmd_modversions_c)                                              \
 299         $(call echo-cmd,record_mcount) $(cmd_record_mcount)
 300 endef
 301
 302 define rule_as_o_S
 303         $(call cmd_and_fixdep,as_o_S)                                     \
 304         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 305         $(cmd_modversions_S)
 306 endef
 307
 308 # List module undefined symbols (or empty line if not enabled)
 309 ifdef CONFIG_TRIM_UNUSED_KSYMS
 310 cmd_undef_syms = $(NM) $@ | sed -n 's/^  *U //p' | xargs echo
 311 else
 312 cmd_undef_syms = echo
 313 endif
 314
 315 # Built-in and composite module parts
 316 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 317         $(call cmd,force_checksrc)
 318         $(call if_changed_rule,cc_o_c)
 319
 320 # Single-part modules are special since we need to mark them in $(MODVERDIR)
 321
 322 $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 323         $(call cmd,force_checksrc)
 324         $(call if_changed_rule,cc_o_c)
 325         @{ echo $(@:.o=.ko); echo $@; \
 326            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 327
 328 quiet_cmd_cc_lst_c = MKLST   $@
 329       cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
 330                      $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
 331                                      System.map $(OBJDUMP) > $@
 332
 333 $(obj)/%.lst: $(src)/%.c FORCE
 334         $(call if_changed_dep,cc_lst_c)
 335
 336 # Compile assembler sources (.S)
 337 # ---------------------------------------------------------------------------
 338
 339 modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
 340
 341 $(real-obj-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 342 $(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 343
 344 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
 345 # or a file that it includes, in order to get versioned symbols. We build a
 346 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
 347 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
 348 #
 349 # This is convoluted. The .S file must first be preprocessed to run guards and
 350 # expand names, then the resulting exports must be constructed into plain
 351 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
 352 # to make the genksyms input.
 353 #
 354 # These mirror gensymtypes_c and co above, keep them in synch.
 355 cmd_gensymtypes_S =                                                         \
 356     (echo "\#include <linux/kernel.h>" ;                                    \
 357      echo "\#include <asm/asm-prototypes.h>" ;                              \
 358     $(CPP) $(a_flags) $< |                                                  \
 359      grep "\<___EXPORT_SYMBOL\>" |                                          \
 360      sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
 361     $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
 362     $(GENKSYMS) $(if $(1), -T $(2))                                         \
 363      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
 364      $(if $(KBUILD_PRESERVE),-p)                                            \
 365      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 366
 367 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
 368 cmd_cc_symtypes_S =                                                         \
 369     set -e;                                                                 \
 370     $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
 371     test -s $@ || rm -f $@
 372
 373 $(obj)/%.symtypes : $(src)/%.S FORCE
 374         $(call cmd,cc_symtypes_S)
 375
 376
 377 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
 378 cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
 379
 380 $(obj)/%.s: $(src)/%.S FORCE
 381         $(call if_changed_dep,cpp_s_S)
 382
 383 quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
 384
 385 ifndef CONFIG_MODVERSIONS
 386 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 387
 388 else
 389
 390 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
 391
 392 ifeq ($(ASM_PROTOTYPES),)
 393 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 394
 395 else
 396
 397 # versioning matches the C process described above, with difference that
 398 # we parse asm-prototypes.h C header to get function definitions.
 399
 400 cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
 401
 402 cmd_modversions_S =                                                             \
 403         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 404                 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 405                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 406                                                                                 \
 407                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
 408                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 409                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 410         else                                                                    \
 411                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 412         fi;
 413 endif
 414 endif
 415
 416 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
 417         $(call if_changed_rule,as_o_S)
 418
 419 targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
 420 targets += $(extra-y) $(MAKECMDGOALS) $(always)
 421
 422 # Linker scripts preprocessor (.lds.S -> .lds)
 423 # ---------------------------------------------------------------------------
 424 quiet_cmd_cpp_lds_S = LDS     $@
 425       cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
 426                              -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
 427
 428 $(obj)/%.lds: $(src)/%.lds.S FORCE
 429         $(call if_changed_dep,cpp_lds_S)
 430
 431 # ASN.1 grammar
 432 # ---------------------------------------------------------------------------
 433 quiet_cmd_asn1_compiler = ASN.1   $@
 434       cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
 435                                 $(subst .h,.c,$@) $(subst .c,.h,$@)
 436
 437 $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 438         $(call cmd,asn1_compiler)
 439
 440 # Build the compiled-in targets
 441 # ---------------------------------------------------------------------------
 442
 443 # To build objects in subdirs, we need to descend into the directories
 444 $(sort $(subdir-obj-y)): $(subdir-ym) ;
 445
 446 #
 447 # Rule to compile a set of .o files into one .o file
 448 #
 449 ifdef builtin-target
 450
 451 # built-in.a archives are made with no symbol table or index which
 452 # makes them small and fast, but unable to be used by the linker.
 453 # scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol
 454 # table and index.
 455 quiet_cmd_ar_builtin = AR      $@
 456       cmd_ar_builtin = rm -f $@; \
 457                      $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^)
 458
 459 $(builtin-target): $(real-obj-y) FORCE
 460         $(call if_changed,ar_builtin)
 461
 462 targets += $(builtin-target)
 463 endif # builtin-target
 464
 465 #
 466 # Rule to create modules.order file
 467 #
 468 # Create commands to either record .ko file or cat modules.order from
 469 # a subdirectory
 470 modorder-cmds =                                         \
 471         $(foreach m, $(modorder),                       \
 472                 $(if $(filter %/modules.order, $m),     \
 473                         cat $m;, echo kernel/$m;))
 474
 475 $(modorder-target): $(subdir-ym) FORCE
 476         $(Q)(cat /dev/null; $(modorder-cmds)) > $@
 477
 478 #
 479 # Rule to compile a set of .o files into one .a file
 480 #
 481 ifdef lib-target
 482 quiet_cmd_link_l_target = AR      $@
 483
 484 # lib target archives do get a symbol table and index
 485 cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
 486
 487 $(lib-target): $(lib-y) FORCE
 488         $(call if_changed,link_l_target)
 489
 490 targets += $(lib-target)
 491
 492 dummy-object = $(obj)/.lib_exports.o
 493 ksyms-lds = $(dot-target).lds
 494
 495 quiet_cmd_export_list = EXPORTS $@
 496 cmd_export_list = $(OBJDUMP) -h $< | \
 497         sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
 498         rm -f $(dummy-object);\
 499         echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
 500         $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
 501         rm $(dummy-object) $(ksyms-lds)
 502
 503 $(obj)/lib-ksyms.o: $(lib-target) FORCE
 504         $(call if_changed,export_list)
 505
 506 targets += $(obj)/lib-ksyms.o
 507
 508 endif
 509
 510 #
 511 # Rule to link composite objects
 512 #
 513 #  Composite objects are specified in kbuild makefile as follows:
 514 #    <composite-object>-objs := <list of .o files>
 515 #  or
 516 #    <composite-object>-y    := <list of .o files>
 517 #  or
 518 #    <composite-object>-m    := <list of .o files>
 519 #  The -m syntax only works if <composite object> is a module
 520 link_multi_deps =                     \
 521 $(filter $(addprefix $(obj)/,         \
 522 $($(subst $(obj)/,,$(@:.o=-objs)))    \
 523 $($(subst $(obj)/,,$(@:.o=-y)))       \
 524 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
 525
 526 quiet_cmd_link_multi-m = LD [M]  $@
 527 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
 528
 529 $(multi-used-m): FORCE
 530         $(call if_changed,link_multi-m)
 531         @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
 532            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 533 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
 534
 535 targets += $(multi-used-m)
 536 targets := $(filter-out $(PHONY), $(targets))
 537
 538 # Add intermediate targets:
 539 # When building objects with specific suffix patterns, add intermediate
 540 # targets that the final targets are derived from.
 541 intermediate_targets = $(foreach sfx, $(2), \
 542                                 $(patsubst %$(strip $(1)),%$(sfx), \
 543                                         $(filter %$(strip $(1)), $(targets))))
 544 # %.asn1.o <- %.asn1.[ch] <- %.asn1
 545 # %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
 546 # %.lex.o <- %.lex.c <- %.l
 547 # %.tab.o <- %.tab.[ch] <- %.y
 548 targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
 549            $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
 550            $(call intermediate_targets, .lex.o, .lex.c) \
 551            $(call intermediate_targets, .tab.o, .tab.c .tab.h)
 552
 553 # Descending
 554 # ---------------------------------------------------------------------------
 555
 556 PHONY += $(subdir-ym)
 557 $(subdir-ym):
 558         $(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1)
 559
 560 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 561 # ---------------------------------------------------------------------------
 562
 563 PHONY += FORCE
 564
 565 FORCE:
 566
 567 # Read all saved command lines and dependencies for the $(targets) we
 568 # may be building above, using $(if_changed{,_dep}). As an
 569 # optimization, we don't need to read them if the target does not
 570 # exist, we will rebuild anyway in that case.
 571
 572 cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
 573
 574 ifneq ($(cmd_files),)
 575   include $(cmd_files)
 576 endif
 577
 578 ifneq ($(KBUILD_SRC),)
 579 # Create directories for object files if they do not exist
 580 obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
 581 # If cmd_files exist, their directories apparently exist.  Skip mkdir.
 582 exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files))))
 583 obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs)))
 584 ifneq ($(obj-dirs),)
 585 $(shell mkdir -p $(obj-dirs))
 586 endif
 587 endif
 588
 589 # Some files contained in $(targets) are intermediate artifacts.
 590 # We never want them to be removed automatically.
 591 .SECONDARY: $(targets)
 592
 593 # Declare the contents of the .PHONY variable as phony.  We keep that
 594 # information in a variable se we can use it in if_changed and friends.
 595
 596 .PHONY: $(PHONY)