1# SPDX-License-Identifier: GPL-2.0 2# ========================================================================== 3# Building 4# ========================================================================== 5 6src := $(obj) 7 8PHONY := __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 14obj-y := 15obj-m := 16lib-y := 17lib-m := 18always := 19targets := 20subdir-y := 21subdir-m := 22EXTRA_AFLAGS := 23EXTRA_CFLAGS := 24EXTRA_CPPFLAGS := 25EXTRA_LDFLAGS := 26asflags-y := 27ccflags-y := 28cppflags-y := 29ldflags-y := 30 31subdir-asflags-y := 32subdir-ccflags-y := 33 34# Read auto.conf if it exists, otherwise ignore 35-include include/config/auto.conf 36 37include scripts/Kbuild.include 38 39# For backward compatibility check that these variables do not change 40save-cflags := $(CFLAGS) 41 42# The filename Kbuild has precedence over Makefile 43kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 44kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) 45include $(kbuild-file) 46 47# If the save-* variables changed error out 48ifeq ($(KBUILD_NOPEDANTIC),) 49 ifneq ("$(save-cflags)","$(CFLAGS)") 50 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y) 51 endif 52endif 53 54include scripts/Makefile.lib 55 56ifdef host-progs 57ifneq ($(hostprogs-y),$(host-progs)) 58$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!) 59hostprogs-y += $(host-progs) 60endif 61endif 62 63# Do not include host rules unless needed 64ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),) 65include scripts/Makefile.host 66endif 67 68ifndef obj 69$(warning kbuild: Makefile.build is included improperly) 70endif 71 72# =========================================================================== 73 74ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 75lib-target := $(obj)/lib.a 76real-obj-y += $(obj)/lib-ksyms.o 77endif 78 79ifneq ($(strip $(real-obj-y) $(need-builtin)),) 80builtin-target := $(obj)/built-in.a 81endif 82 83modorder-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) $(always) 90 @: 91 92# Linus' kernel sanity checking tool 93ifneq ($(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) $< ; 100 endif 101endif 102 103ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),) 104 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< ; 105endif 106 107# Do section mismatch analysis for each module/built-in.a 108ifdef CONFIG_DEBUG_SECTION_MISMATCH 109 cmd_secanalysis = ; scripts/mod/modpost $@ 110endif 111 112# Compile C sources (.c) 113# --------------------------------------------------------------------------- 114 115# Default is built-in, unless we know otherwise 116modkern_cflags = \ 117 $(if $(part-of-module), \ 118 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \ 119 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL)) 120quiet_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 134quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 135cmd_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 140quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 141cmd_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. 147cmd_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 154quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 155cmd_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 165quiet_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 175quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 176 177ifndef CONFIG_MODVERSIONS 178cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 179 180else 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 193cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $< 194 195cmd_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) $@; \ 205 fi; 206endif 207 208ifdef CONFIG_FTRACE_MCOUNT_RECORD 209ifdef BUILD_C_RECORDMCOUNT 210ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 211 RECORDMCOUNT_FLAGS = -w 212endif 213# Due to recursion, we must skip empty.o. 214# The empty.o file is created in the make process in order to determine 215# the target endianness and word size. It is made before all other C 216# files, including recordmcount. 217sub_cmd_record_mcount = \ 218 if [ $(@) != "scripts/mod/empty.o" ]; then \ 219 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 220 fi; 221recordmcount_source := $(srctree)/scripts/recordmcount.c \ 222 $(srctree)/scripts/recordmcount.h 223else 224sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 225 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 226 "$(if $(CONFIG_64BIT),64,32)" \ 227 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \ 228 "$(LD)" "$(NM)" "$(RM)" "$(MV)" \ 229 "$(if $(part-of-module),1,0)" "$(@)"; 230recordmcount_source := $(srctree)/scripts/recordmcount.pl 231endif # BUILD_C_RECORDMCOUNT 232cmd_record_mcount = \ 233 if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" = \ 234 "$(CC_FLAGS_FTRACE)" ]; then \ 235 $(sub_cmd_record_mcount) \ 236 fi; 237endif # CONFIG_FTRACE_MCOUNT_RECORD 238 239ifdef CONFIG_STACK_VALIDATION 240ifneq ($(SKIP_STACK_VALIDATION),1) 241 242__objtool_obj := $(objtree)/tools/objtool/objtool 243 244objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check) 245 246objtool_args += $(if $(part-of-module), --module,) 247 248ifndef CONFIG_FRAME_POINTER 249objtool_args += --no-fp 250endif 251ifdef CONFIG_GCOV_KERNEL 252objtool_args += --no-unreachable 253else 254objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable) 255endif 256ifdef CONFIG_RETPOLINE 257ifneq ($(RETPOLINE_CFLAGS),) 258 objtool_args += --retpoline 259endif 260endif 261 262 263ifdef CONFIG_MODVERSIONS 264objtool_o = $(@D)/.tmp_$(@F) 265else 266objtool_o = $(@) 267endif 268 269# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 270# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 271# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 272cmd_objtool = $(if $(patsubst y%,, \ 273 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 274 $(__objtool_obj) $(objtool_args) "$(objtool_o)";) 275objtool_obj = $(if $(patsubst y%,, \ 276 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 277 $(__objtool_obj)) 278 279endif # SKIP_STACK_VALIDATION 280endif # CONFIG_STACK_VALIDATION 281 282# Rebuild all objects when objtool changes, or is enabled/disabled. 283objtool_dep = $(objtool_obj) \ 284 $(wildcard include/config/orc/unwinder.h \ 285 include/config/stack/validation.h) 286 287define rule_cc_o_c 288 $(call echo-cmd,checksrc) $(cmd_checksrc) \ 289 $(call cmd_and_fixdep,cc_o_c) \ 290 $(cmd_checkdoc) \ 291 $(call echo-cmd,objtool) $(cmd_objtool) \ 292 $(cmd_modversions_c) \ 293 $(call echo-cmd,record_mcount) $(cmd_record_mcount) 294endef 295 296define rule_as_o_S 297 $(call cmd_and_fixdep,as_o_S) \ 298 $(call echo-cmd,objtool) $(cmd_objtool) \ 299 $(cmd_modversions_S) 300endef 301 302# List module undefined symbols (or empty line if not enabled) 303ifdef CONFIG_TRIM_UNUSED_KSYMS 304cmd_undef_syms = $(NM) $@ | sed -n 's/^ *U //p' | xargs echo 305else 306cmd_undef_syms = echo 307endif 308 309# Built-in and composite module parts 310$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE 311 $(call cmd,force_checksrc) 312 $(call if_changed_rule,cc_o_c) 313 314# Single-part modules are special since we need to mark them in $(MODVERDIR) 315 316$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE 317 $(call cmd,force_checksrc) 318 $(call if_changed_rule,cc_o_c) 319 @{ echo $(@:.o=.ko); echo $@; \ 320 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod) 321 322quiet_cmd_cc_lst_c = MKLST $@ 323 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 324 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 325 System.map $(OBJDUMP) > $@ 326 327$(obj)/%.lst: $(src)/%.c FORCE 328 $(call if_changed_dep,cc_lst_c) 329 330# Compile assembler sources (.S) 331# --------------------------------------------------------------------------- 332 333modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) 334 335$(real-obj-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) 336$(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) 337 338# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 339# or a file that it includes, in order to get versioned symbols. We build a 340# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 341# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 342# 343# This is convoluted. The .S file must first be preprocessed to run guards and 344# expand names, then the resulting exports must be constructed into plain 345# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 346# to make the genksyms input. 347# 348# These mirror gensymtypes_c and co above, keep them in synch. 349cmd_gensymtypes_S = \ 350 (echo "\#include <linux/kernel.h>" ; \ 351 echo "\#include <asm/asm-prototypes.h>" ; \ 352 $(CPP) $(a_flags) $< | \ 353 grep "\<___EXPORT_SYMBOL\>" | \ 354 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \ 355 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 356 $(GENKSYMS) $(if $(1), -T $(2)) \ 357 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 358 $(if $(KBUILD_PRESERVE),-p) \ 359 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 360 361quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 362cmd_cc_symtypes_S = \ 363 set -e; \ 364 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 365 test -s $@ || rm -f $@ 366 367$(obj)/%.symtypes : $(src)/%.S FORCE 368 $(call cmd,cc_symtypes_S) 369 370 371quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 372cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 373 374$(obj)/%.s: $(src)/%.S FORCE 375 $(call if_changed_dep,cpp_s_S) 376 377quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 378 379ifndef CONFIG_MODVERSIONS 380cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 381 382else 383 384ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h) 385 386ifeq ($(ASM_PROTOTYPES),) 387cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 388 389else 390 391# versioning matches the C process described above, with difference that 392# we parse asm-prototypes.h C header to get function definitions. 393 394cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $< 395 396cmd_modversions_S = \ 397 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \ 398 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 399 > $(@D)/.tmp_$(@F:.o=.ver); \ 400 \ 401 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \ 402 -T $(@D)/.tmp_$(@F:.o=.ver); \ 403 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \ 404 else \ 405 mv -f $(@D)/.tmp_$(@F) $@; \ 406 fi; 407endif 408endif 409 410$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE 411 $(call if_changed_rule,as_o_S) 412 413targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y) 414targets += $(extra-y) $(MAKECMDGOALS) $(always) 415 416# Linker scripts preprocessor (.lds.S -> .lds) 417# --------------------------------------------------------------------------- 418quiet_cmd_cpp_lds_S = LDS $@ 419 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 420 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 421 422$(obj)/%.lds: $(src)/%.lds.S FORCE 423 $(call if_changed_dep,cpp_lds_S) 424 425# ASN.1 grammar 426# --------------------------------------------------------------------------- 427quiet_cmd_asn1_compiler = ASN.1 $@ 428 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 429 $(subst .h,.c,$@) $(subst .c,.h,$@) 430 431$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 432 $(call cmd,asn1_compiler) 433 434# Build the compiled-in targets 435# --------------------------------------------------------------------------- 436 437# To build objects in subdirs, we need to descend into the directories 438$(sort $(subdir-obj-y)): $(subdir-ym) ; 439 440# 441# Rule to compile a set of .o files into one .o file 442# 443ifdef builtin-target 444 445# built-in.a archives are made with no symbol table or index which 446# makes them small and fast, but unable to be used by the linker. 447# scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol 448# table and index. 449quiet_cmd_ar_builtin = AR $@ 450 cmd_ar_builtin = rm -f $@; \ 451 $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^) 452 453$(builtin-target): $(real-obj-y) FORCE 454 $(call if_changed,ar_builtin) 455 456targets += $(builtin-target) 457endif # builtin-target 458 459# 460# Rule to create modules.order file 461# 462# Create commands to either record .ko file or cat modules.order from 463# a subdirectory 464modorder-cmds = \ 465 $(foreach m, $(modorder), \ 466 $(if $(filter %/modules.order, $m), \ 467 cat $m;, echo kernel/$m;)) 468 469$(modorder-target): $(subdir-ym) FORCE 470 $(Q)(cat /dev/null; $(modorder-cmds)) > $@ 471 472# 473# Rule to compile a set of .o files into one .a file 474# 475ifdef lib-target 476quiet_cmd_link_l_target = AR $@ 477 478# lib target archives do get a symbol table and index 479cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y) 480 481$(lib-target): $(lib-y) FORCE 482 $(call if_changed,link_l_target) 483 484targets += $(lib-target) 485 486dummy-object = $(obj)/.lib_exports.o 487ksyms-lds = $(dot-target).lds 488 489quiet_cmd_export_list = EXPORTS $@ 490cmd_export_list = $(OBJDUMP) -h $< | \ 491 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\ 492 rm -f $(dummy-object);\ 493 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\ 494 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\ 495 rm $(dummy-object) $(ksyms-lds) 496 497$(obj)/lib-ksyms.o: $(lib-target) FORCE 498 $(call if_changed,export_list) 499 500targets += $(obj)/lib-ksyms.o 501 502endif 503 504# 505# Rule to link composite objects 506# 507# Composite objects are specified in kbuild makefile as follows: 508# <composite-object>-objs := <list of .o files> 509# or 510# <composite-object>-y := <list of .o files> 511# or 512# <composite-object>-m := <list of .o files> 513# The -m syntax only works if <composite object> is a module 514link_multi_deps = \ 515$(filter $(addprefix $(obj)/, \ 516$($(subst $(obj)/,,$(@:.o=-objs))) \ 517$($(subst $(obj)/,,$(@:.o=-y))) \ 518$($(subst $(obj)/,,$(@:.o=-m)))), $^) 519 520quiet_cmd_link_multi-m = LD [M] $@ 521cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) 522 523$(multi-used-m): FORCE 524 $(call if_changed,link_multi-m) 525 @{ echo $(@:.o=.ko); echo $(link_multi_deps); \ 526 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod) 527$(call multi_depend, $(multi-used-m), .o, -objs -y -m) 528 529targets += $(multi-used-m) 530targets := $(filter-out $(PHONY), $(targets)) 531 532# Add intermediate targets: 533# When building objects with specific suffix patterns, add intermediate 534# targets that the final targets are derived from. 535intermediate_targets = $(foreach sfx, $(2), \ 536 $(patsubst %$(strip $(1)),%$(sfx), \ 537 $(filter %$(strip $(1)), $(targets)))) 538# %.asn1.o <- %.asn1.[ch] <- %.asn1 539# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 540# %.lex.o <- %.lex.c <- %.l 541# %.tab.o <- %.tab.[ch] <- %.y 542targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 543 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 544 $(call intermediate_targets, .lex.o, .lex.c) \ 545 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 546 547# Descending 548# --------------------------------------------------------------------------- 549 550PHONY += $(subdir-ym) 551$(subdir-ym): 552 $(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1) 553 554# Add FORCE to the prequisites of a target to force it to be always rebuilt. 555# --------------------------------------------------------------------------- 556 557PHONY += FORCE 558 559FORCE: 560 561# Read all saved command lines and dependencies for the $(targets) we 562# may be building above, using $(if_changed{,_dep}). As an 563# optimization, we don't need to read them if the target does not 564# exist, we will rebuild anyway in that case. 565 566cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd)) 567 568ifneq ($(cmd_files),) 569 include $(cmd_files) 570endif 571 572ifneq ($(KBUILD_SRC),) 573# Create directories for object files if they do not exist 574obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets)))) 575# If cmd_files exist, their directories apparently exist. Skip mkdir. 576exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files)))) 577obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs))) 578ifneq ($(obj-dirs),) 579$(shell mkdir -p $(obj-dirs)) 580endif 581endif 582 583# Some files contained in $(targets) are intermediate artifacts. 584# We never want them to be removed automatically. 585.SECONDARY: $(targets) 586 587# Declare the contents of the .PHONY variable as phony. We keep that 588# information in a variable se we can use it in if_changed and friends. 589 590.PHONY: $(PHONY) 591