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-y := 19always-m := 20targets := 21subdir-y := 22subdir-m := 23EXTRA_AFLAGS := 24EXTRA_CFLAGS := 25EXTRA_CPPFLAGS := 26EXTRA_LDFLAGS := 27asflags-y := 28ccflags-y := 29cppflags-y := 30ldflags-y := 31 32subdir-asflags-y := 33subdir-ccflags-y := 34 35# Read auto.conf if it exists, otherwise ignore 36-include include/config/auto.conf 37 38include $(srctree)/scripts/Kbuild.include 39include $(srctree)/scripts/Makefile.compiler 40 41# The filename Kbuild has precedence over Makefile 42kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 43kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) 44include $(kbuild-file) 45 46include $(srctree)/scripts/Makefile.lib 47 48# Do not include hostprogs rules unless needed. 49# $(sort ...) is used here to remove duplicated words and excessive spaces. 50hostprogs := $(sort $(hostprogs)) 51ifneq ($(hostprogs),) 52include $(srctree)/scripts/Makefile.host 53endif 54 55# Do not include userprogs rules unless needed. 56# $(sort ...) is used here to remove duplicated words and excessive spaces. 57userprogs := $(sort $(userprogs)) 58ifneq ($(userprogs),) 59include $(srctree)/scripts/Makefile.userprogs 60endif 61 62ifndef obj 63$(warning kbuild: Makefile.build is included improperly) 64endif 65 66ifeq ($(need-modorder),) 67ifneq ($(obj-m),) 68$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 69$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 70endif 71endif 72 73# =========================================================================== 74 75# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...) 76subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y))) 77subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) 78 79targets-for-builtin := $(extra-y) 80 81ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 82targets-for-builtin += $(obj)/lib.a 83endif 84 85ifdef need-builtin 86targets-for-builtin += $(obj)/built-in.a 87endif 88 89targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \ 90 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) 91 92ifdef CONFIG_LTO_CLANG 93targets-for-modules += $(patsubst %.o, %.lto.o, $(filter %.o, $(obj-m))) 94endif 95 96ifdef need-modorder 97targets-for-modules += $(obj)/modules.order 98endif 99 100targets += $(targets-for-builtin) $(targets-for-modules) 101 102# Linus' kernel sanity checking tool 103ifeq ($(KBUILD_CHECKSRC),1) 104 quiet_cmd_checksrc = CHECK $< 105 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 106else ifeq ($(KBUILD_CHECKSRC),2) 107 quiet_cmd_force_checksrc = CHECK $< 108 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 109endif 110 111ifneq ($(KBUILD_EXTRA_WARN),) 112 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 113endif 114 115# Compile C sources (.c) 116# --------------------------------------------------------------------------- 117 118quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 119 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< 120 121$(obj)/%.s: $(src)/%.c FORCE 122 $(call if_changed_dep,cc_s_c) 123 124quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 125cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 126 127$(obj)/%.i: $(src)/%.c FORCE 128 $(call if_changed_dep,cpp_i_c) 129 130# These mirror gensymtypes_S and co below, keep them in synch. 131cmd_gensymtypes_c = \ 132 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 133 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 134 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 135 $(if $(KBUILD_PRESERVE),-p) \ 136 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 137 138quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 139cmd_cc_symtypes_c = \ 140 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ 141 test -s $@ || rm -f $@ 142 143$(obj)/%.symtypes : $(src)/%.c FORCE 144 $(call cmd,cc_symtypes_c) 145 146# LLVM assembly 147# Generate .ll files from .c 148quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 149 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< 150 151$(obj)/%.ll: $(src)/%.c FORCE 152 $(call if_changed_dep,cc_ll_c) 153 154# C (.c) files 155# The C file is compiled and updated dependency information is generated. 156# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 157 158quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 159 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 160 161ifdef CONFIG_MODVERSIONS 162# When module versioning is enabled the following steps are executed: 163# o compile a <file>.o from <file>.c 164# o if <file>.o doesn't contain a __ksymtab version, i.e. does 165# not export symbols, it's done. 166# o otherwise, we calculate symbol versions using the good old 167# genksyms on the preprocessed source and postprocess them in a way 168# that they are usable as a linker script 169# o generate .tmp_<file>.o from <file>.o using the linker to 170# replace the unresolved symbols __crc_exported_symbol with 171# the actual value of the checksum generated by genksyms 172# o remove .tmp_<file>.o to <file>.o 173 174ifdef CONFIG_LTO_CLANG 175# Generate .o.symversions files for each .o with exported symbols, and link these 176# to the kernel and/or modules at the end. 177cmd_modversions_c = \ 178 if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ 179 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 180 > $@.symversions; \ 181 else \ 182 rm -f $@.symversions; \ 183 fi; 184else 185cmd_modversions_c = \ 186 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 187 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 188 > $(@D)/.tmp_$(@F:.o=.ver); \ 189 \ 190 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 191 -T $(@D)/.tmp_$(@F:.o=.ver); \ 192 mv -f $(@D)/.tmp_$(@F) $@; \ 193 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 194 fi 195endif 196endif 197 198ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 199# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 200ifdef BUILD_C_RECORDMCOUNT 201ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 202 RECORDMCOUNT_FLAGS = -w 203endif 204# Due to recursion, we must skip empty.o. 205# The empty.o file is created in the make process in order to determine 206# the target endianness and word size. It is made before all other C 207# files, including recordmcount. 208sub_cmd_record_mcount = \ 209 if [ $(@) != "scripts/mod/empty.o" ]; then \ 210 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 211 fi; 212recordmcount_source := $(srctree)/scripts/recordmcount.c \ 213 $(srctree)/scripts/recordmcount.h 214else 215sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 216 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 217 "$(if $(CONFIG_64BIT),64,32)" \ 218 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 219 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 220 "$(if $(part-of-module),1,0)" "$(@)"; 221recordmcount_source := $(srctree)/scripts/recordmcount.pl 222endif # BUILD_C_RECORDMCOUNT 223cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 224 $(sub_cmd_record_mcount)) 225endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 226 227ifdef CONFIG_STACK_VALIDATION 228 229objtool_args = \ 230 $(if $(CONFIG_UNWINDER_ORC),orc generate,check) \ 231 $(if $(part-of-module), --module) \ 232 $(if $(CONFIG_FRAME_POINTER),, --no-fp) \ 233 $(if $(CONFIG_GCOV_KERNEL)$(CONFIG_LTO_CLANG), --no-unreachable)\ 234 $(if $(CONFIG_RETPOLINE), --retpoline) \ 235 $(if $(CONFIG_RETHUNK), --rethunk) \ 236 $(if $(CONFIG_X86_SMAP), --uaccess) \ 237 $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \ 238 $(if $(CONFIG_SLS), --sls) 239 240ifndef CONFIG_LTO_CLANG 241 242__objtool_obj := $(objtree)/tools/objtool/objtool 243 244# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 245# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 246# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 247cmd_objtool = $(if $(patsubst y%,, \ 248 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 249 $(__objtool_obj) $(objtool_args) $@) 250objtool_obj = $(if $(patsubst y%,, \ 251 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 252 $(__objtool_obj)) 253 254endif # CONFIG_LTO_CLANG 255endif # CONFIG_STACK_VALIDATION 256 257# Rebuild all objects when objtool changes, or is enabled/disabled. 258objtool_dep = $(objtool_obj) \ 259 $(wildcard include/config/ORC_UNWINDER \ 260 include/config/STACK_VALIDATION) 261 262ifdef CONFIG_TRIM_UNUSED_KSYMS 263cmd_gen_ksymdeps = \ 264 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 265endif 266 267define rule_cc_o_c 268 $(call cmd_and_fixdep,cc_o_c) 269 $(call cmd,gen_ksymdeps) 270 $(call cmd,checksrc) 271 $(call cmd,checkdoc) 272 $(call cmd,objtool) 273 $(call cmd,modversions_c) 274 $(call cmd,record_mcount) 275endef 276 277define rule_as_o_S 278 $(call cmd_and_fixdep,as_o_S) 279 $(call cmd,gen_ksymdeps) 280 $(call cmd,objtool) 281 $(call cmd,modversions_S) 282endef 283 284# Built-in and composite module parts 285.SECONDEXPANSION: 286$(obj)/%.o: $(src)/%.c $(recordmcount_source) $$(objtool_dep) FORCE 287 $(call if_changed_rule,cc_o_c) 288 $(call cmd,force_checksrc) 289 290ifdef CONFIG_LTO_CLANG 291# Module .o files may contain LLVM bitcode, compile them into native code 292# before ELF processing 293quiet_cmd_cc_lto_link_modules = LTO [M] $@ 294cmd_cc_lto_link_modules = \ 295 $(LD) $(ld_flags) -r -o $@ \ 296 $(shell [ -s $(@:.lto.o=.o.symversions) ] && \ 297 echo -T $(@:.lto.o=.o.symversions)) \ 298 --whole-archive $(filter-out FORCE,$^) 299 300ifdef CONFIG_STACK_VALIDATION 301# objtool was skipped for LLVM bitcode, run it now that we have compiled 302# modules into native code 303cmd_cc_lto_link_modules += ; \ 304 $(objtree)/tools/objtool/objtool $(objtool_args) --module $@ 305endif 306 307$(obj)/%.lto.o: $(obj)/%.o FORCE 308 $(call if_changed,cc_lto_link_modules) 309endif 310 311cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ 312 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ 313 314$(obj)/%.mod: FORCE 315 $(call if_changed,mod) 316 317# List module undefined symbols 318cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@ 319 320$(obj)/%.usyms: $(obj)/%$(mod-prelink-ext).o FORCE 321 $(call if_changed,undefined_syms) 322 323quiet_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# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 335# or a file that it includes, in order to get versioned symbols. We build a 336# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 337# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 338# 339# This is convoluted. The .S file must first be preprocessed to run guards and 340# expand names, then the resulting exports must be constructed into plain 341# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 342# to make the genksyms input. 343# 344# These mirror gensymtypes_c and co above, keep them in synch. 345cmd_gensymtypes_S = \ 346 { echo "\#include <linux/kernel.h>" ; \ 347 echo "\#include <asm/asm-prototypes.h>" ; \ 348 $(CPP) $(a_flags) $< | \ 349 grep "\<___EXPORT_SYMBOL\>" | \ 350 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 351 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 352 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 353 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 354 $(if $(KBUILD_PRESERVE),-p) \ 355 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 356 357quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 358cmd_cc_symtypes_S = \ 359 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 360 test -s $@ || rm -f $@ 361 362$(obj)/%.symtypes : $(src)/%.S FORCE 363 $(call cmd,cc_symtypes_S) 364 365 366quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 367cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 368 369$(obj)/%.s: $(src)/%.S FORCE 370 $(call if_changed_dep,cpp_s_S) 371 372quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 373 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 374 375ifdef CONFIG_ASM_MODVERSIONS 376 377# versioning matches the C process described above, with difference that 378# we parse asm-prototypes.h C header to get function definitions. 379 380cmd_modversions_S = \ 381 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 382 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 383 > $(@D)/.tmp_$(@F:.o=.ver); \ 384 \ 385 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 386 -T $(@D)/.tmp_$(@F:.o=.ver); \ 387 mv -f $(@D)/.tmp_$(@F) $@; \ 388 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 389 fi 390endif 391 392$(obj)/%.o: $(src)/%.S $$(objtool_dep) FORCE 393 $(call if_changed_rule,as_o_S) 394 395targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 396targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 397targets += $(real-dtb-y) $(lib-y) $(always-y) $(MAKECMDGOALS) 398 399# Linker scripts preprocessor (.lds.S -> .lds) 400# --------------------------------------------------------------------------- 401quiet_cmd_cpp_lds_S = LDS $@ 402 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 403 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 404 405$(obj)/%.lds: $(src)/%.lds.S FORCE 406 $(call if_changed_dep,cpp_lds_S) 407 408# ASN.1 grammar 409# --------------------------------------------------------------------------- 410quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 411 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 412 $(basename $@).c $(basename $@).h 413 414$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 415 $(call cmd,asn1_compiler) 416 417# Build the compiled-in targets 418# --------------------------------------------------------------------------- 419 420# To build objects in subdirs, we need to descend into the directories 421$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 422$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 423 424# combine symversions for later processing 425ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y) 426 cmd_update_lto_symversions = \ 427 rm -f $@.symversions \ 428 $(foreach n, $(filter-out FORCE,$^), \ 429 $(if $(shell test -s $(n).symversions && echo y), \ 430 ; cat $(n).symversions >> $@.symversions)) 431else 432 cmd_update_lto_symversions = echo >/dev/null 433endif 434 435# 436# Rule to compile a set of .o files into one .a file (without symbol table) 437# 438 439quiet_cmd_ar_builtin = AR $@ 440 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) 441 442quiet_cmd_ar_and_symver = AR $@ 443 cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin) 444 445$(obj)/built-in.a: $(real-obj-y) FORCE 446 $(call if_changed,ar_and_symver) 447 448# 449# Rule to create modules.order file 450# 451# Create commands to either record .ko file or cat modules.order from 452# a subdirectory 453# Add $(obj-m) as the prerequisite to avoid updating the timestamp of 454# modules.order unless contained modules are updated. 455 456cmd_modules_order = { $(foreach m, $(real-prereqs), \ 457 $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \ 458 | $(AWK) '!x[$$0]++' - > $@ 459 460$(obj)/modules.order: $(obj-m) FORCE 461 $(call if_changed,modules_order) 462 463# 464# Rule to compile a set of .o files into one .a file (with symbol table) 465# 466quiet_cmd_ar_lib = AR $@ 467 cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar) 468 469$(obj)/lib.a: $(lib-y) FORCE 470 $(call if_changed,ar_lib) 471 472ifdef CONFIG_LTO_CLANG 473quiet_cmd_link_multi-m = AR [M] $@ 474cmd_link_multi-m = \ 475 $(cmd_update_lto_symversions); \ 476 rm -f $@; \ 477 $(AR) cDPrsT $@ @$(patsubst %.o,%.mod,$@) 478else 479quiet_cmd_link_multi-m = LD [M] $@ 480 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) 481endif 482 483$(multi-obj-m): %.o: %.mod FORCE 484 $(call if_changed,link_multi-m) 485$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 486 487targets := $(filter-out $(PHONY), $(targets)) 488 489# Add intermediate targets: 490# When building objects with specific suffix patterns, add intermediate 491# targets that the final targets are derived from. 492intermediate_targets = $(foreach sfx, $(2), \ 493 $(patsubst %$(strip $(1)),%$(sfx), \ 494 $(filter %$(strip $(1)), $(targets)))) 495# %.asn1.o <- %.asn1.[ch] <- %.asn1 496# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 497# %.lex.o <- %.lex.c <- %.l 498# %.tab.o <- %.tab.[ch] <- %.y 499targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 500 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 501 $(call intermediate_targets, .lex.o, .lex.c) \ 502 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 503 504# Build 505# --------------------------------------------------------------------------- 506 507ifdef single-build 508 509KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS)) 510 511curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ 512 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) 513 514# Handle single targets without any rule: show "Nothing to be done for ..." or 515# "No rule to make target ..." depending on whether the target exists. 516unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ 517 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS))) 518 519single-subdirs := $(foreach d, $(subdir-ym), \ 520 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d))) 521 522__build: $(curdir-single) $(single-subdirs) 523ifneq ($(unknown-single),) 524 $(Q)$(MAKE) -f /dev/null $(unknown-single) 525endif 526 @: 527 528ifeq ($(curdir-single),) 529# Nothing to do in this directory. Do not include any .*.cmd file for speed-up 530targets := 531else 532targets += $(curdir-single) 533endif 534 535else 536 537__build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 538 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 539 $(subdir-ym) $(always-y) 540 @: 541 542endif 543 544# Descending 545# --------------------------------------------------------------------------- 546 547PHONY += $(subdir-ym) 548$(subdir-ym): 549 $(Q)$(MAKE) $(build)=$@ \ 550 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ 551 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 552 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),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 566existing-targets := $(wildcard $(sort $(targets))) 567 568-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 569 570# Create directories for object files if they do not exist 571obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 572# If targets exist, their directories apparently exist. Skip mkdir. 573existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 574obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 575ifneq ($(obj-dirs),) 576$(shell mkdir -p $(obj-dirs)) 577endif 578 579.PHONY: $(PHONY) 580