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