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)) 43include $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile) 44 45include $(srctree)/scripts/Makefile.lib 46 47# Do not include hostprogs rules unless needed. 48# $(sort ...) is used here to remove duplicated words and excessive spaces. 49hostprogs := $(sort $(hostprogs)) 50ifneq ($(hostprogs),) 51include $(srctree)/scripts/Makefile.host 52endif 53 54# Do not include userprogs rules unless needed. 55# $(sort ...) is used here to remove duplicated words and excessive spaces. 56userprogs := $(sort $(userprogs)) 57ifneq ($(userprogs),) 58include $(srctree)/scripts/Makefile.userprogs 59endif 60 61ifndef obj 62$(warning kbuild: Makefile.build is included improperly) 63endif 64 65ifeq ($(need-modorder),) 66ifneq ($(obj-m),) 67$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 68$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 69endif 70endif 71 72# =========================================================================== 73 74# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...) 75subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y))) 76subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) 77 78targets-for-builtin := $(extra-y) 79 80ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 81targets-for-builtin += $(obj)/lib.a 82endif 83 84ifdef need-builtin 85targets-for-builtin += $(obj)/built-in.a 86endif 87 88targets-for-modules := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m))) 89 90ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) 91targets-for-modules += $(patsubst %.o, %.prelink.o, $(filter %.o, $(obj-m))) 92endif 93 94ifdef need-modorder 95targets-for-modules += $(obj)/modules.order 96endif 97 98targets += $(targets-for-builtin) $(targets-for-modules) 99 100# Linus' kernel sanity checking tool 101ifeq ($(KBUILD_CHECKSRC),1) 102 quiet_cmd_checksrc = CHECK $< 103 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 104else ifeq ($(KBUILD_CHECKSRC),2) 105 quiet_cmd_force_checksrc = CHECK $< 106 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 107endif 108 109ifneq ($(KBUILD_EXTRA_WARN),) 110 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 111endif 112 113# Compile C sources (.c) 114# --------------------------------------------------------------------------- 115 116quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 117 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< 118 119$(obj)/%.s: $(src)/%.c FORCE 120 $(call if_changed_dep,cc_s_c) 121 122quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 123cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 124 125$(obj)/%.i: $(src)/%.c FORCE 126 $(call if_changed_dep,cpp_i_c) 127 128# These mirror gensymtypes_S and co below, keep them in synch. 129cmd_gensymtypes_c = \ 130 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 131 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 132 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 133 $(if $(KBUILD_PRESERVE),-p) \ 134 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 135 136quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 137cmd_cc_symtypes_c = \ 138 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ 139 test -s $@ || rm -f $@ 140 141$(obj)/%.symtypes : $(src)/%.c FORCE 142 $(call cmd,cc_symtypes_c) 143 144# LLVM assembly 145# Generate .ll files from .c 146quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 147 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< 148 149$(obj)/%.ll: $(src)/%.c FORCE 150 $(call if_changed_dep,cc_ll_c) 151 152# C (.c) files 153# The C file is compiled and updated dependency information is generated. 154# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 155 156quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 157 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< $(cmd_objtool) 158 159ifdef CONFIG_MODVERSIONS 160# When module versioning is enabled the following steps are executed: 161# o compile a <file>.o from <file>.c 162# o if <file>.o doesn't contain a __ksymtab version, i.e. does 163# not export symbols, it's done. 164# o otherwise, we calculate symbol versions using the good old 165# genksyms on the preprocessed source and postprocess them in a way 166# that they are usable as a linker script 167# o generate .tmp_<file>.o from <file>.o using the linker to 168# replace the unresolved symbols __crc_exported_symbol with 169# the actual value of the checksum generated by genksyms 170# o remove .tmp_<file>.o to <file>.o 171 172ifdef CONFIG_LTO_CLANG 173# Generate .o.symversions files for each .o with exported symbols, and link these 174# to the kernel and/or modules at the end. 175cmd_modversions_c = \ 176 if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ 177 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 178 > $@.symversions; \ 179 else \ 180 rm -f $@.symversions; \ 181 fi; 182else 183cmd_modversions_c = \ 184 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 185 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 186 > $(@D)/.tmp_$(@F:.o=.ver); \ 187 \ 188 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 189 -T $(@D)/.tmp_$(@F:.o=.ver); \ 190 mv -f $(@D)/.tmp_$(@F) $@; \ 191 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 192 fi 193endif 194endif 195 196ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 197# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 198ifdef BUILD_C_RECORDMCOUNT 199ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 200 RECORDMCOUNT_FLAGS = -w 201endif 202# Due to recursion, we must skip empty.o. 203# The empty.o file is created in the make process in order to determine 204# the target endianness and word size. It is made before all other C 205# files, including recordmcount. 206sub_cmd_record_mcount = \ 207 if [ $(@) != "scripts/mod/empty.o" ]; then \ 208 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 209 fi; 210recordmcount_source := $(srctree)/scripts/recordmcount.c \ 211 $(srctree)/scripts/recordmcount.h 212else 213sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 214 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 215 "$(if $(CONFIG_64BIT),64,32)" \ 216 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 217 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 218 "$(if $(part-of-module),1,0)" "$(@)"; 219recordmcount_source := $(srctree)/scripts/recordmcount.pl 220endif # BUILD_C_RECORDMCOUNT 221cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 222 $(sub_cmd_record_mcount)) 223endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 224 225ifdef CONFIG_OBJTOOL 226 227objtool := $(objtree)/tools/objtool/objtool 228 229objtool_args = \ 230 $(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label) \ 231 $(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \ 232 $(if $(CONFIG_X86_KERNEL_IBT), --ibt) \ 233 $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \ 234 $(if $(CONFIG_UNWINDER_ORC), --orc) \ 235 $(if $(CONFIG_RETPOLINE), --retpoline) \ 236 $(if $(CONFIG_SLS), --sls) \ 237 $(if $(CONFIG_STACK_VALIDATION), --stackval) \ 238 $(if $(CONFIG_HAVE_STATIC_CALL_INLINE), --static-call) \ 239 --uaccess \ 240 $(if $(linked-object), --link) \ 241 $(if $(part-of-module), --module) \ 242 $(if $(CONFIG_GCOV_KERNEL), --no-unreachable) 243 244cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@) 245cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd) 246 247endif # CONFIG_OBJTOOL 248 249ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) 250 251# Skip objtool for LLVM bitcode 252$(obj)/%.o: objtool-enabled := 253 254else 255 256# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 257# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 258# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 259 260$(obj)/%.o: objtool-enabled = $(if $(filter-out y%, \ 261 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y) 262 263endif 264 265ifdef CONFIG_TRIM_UNUSED_KSYMS 266cmd_gen_ksymdeps = \ 267 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 268 269# List module undefined symbols 270undefined_syms = $(NM) $< | $(AWK) '$$1 == "U" { printf("%s%s", x++ ? " " : "", $$2) }'; 271endif 272 273define rule_cc_o_c 274 $(call cmd_and_fixdep,cc_o_c) 275 $(call cmd,gen_ksymdeps) 276 $(call cmd,checksrc) 277 $(call cmd,checkdoc) 278 $(call cmd,gen_objtooldep) 279 $(call cmd,modversions_c) 280 $(call cmd,record_mcount) 281endef 282 283define rule_as_o_S 284 $(call cmd_and_fixdep,as_o_S) 285 $(call cmd,gen_ksymdeps) 286 $(call cmd,gen_objtooldep) 287 $(call cmd,modversions_S) 288endef 289 290# Built-in and composite module parts 291$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE 292 $(call if_changed_rule,cc_o_c) 293 $(call cmd,force_checksrc) 294 295ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) 296# Module .o files may contain LLVM bitcode, compile them into native code 297# before ELF processing 298quiet_cmd_cc_prelink_modules = LD [M] $@ 299 cmd_cc_prelink_modules = \ 300 $(LD) $(ld_flags) -r -o $@ \ 301 $(shell [ -s $(@:.prelink.o=.o.symversions) ] && \ 302 echo -T $(@:.prelink.o=.o.symversions)) \ 303 --whole-archive $(filter-out FORCE,$^) \ 304 $(cmd_objtool) 305 306# objtool was skipped for LLVM bitcode, run it now that we have compiled 307# modules into native code 308$(obj)/%.prelink.o: objtool-enabled = y 309$(obj)/%.prelink.o: part-of-module := y 310$(obj)/%.prelink.o: linked-object := y 311 312$(obj)/%.prelink.o: $(obj)/%.o FORCE 313 $(call if_changed,cc_prelink_modules) 314endif 315 316cmd_mod = { \ 317 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ 318 $(undefined_syms) echo; \ 319 } > $@ 320 321$(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE 322 $(call if_changed,mod) 323 324quiet_cmd_cc_lst_c = MKLST $@ 325 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 326 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 327 System.map $(OBJDUMP) > $@ 328 329$(obj)/%.lst: $(src)/%.c FORCE 330 $(call if_changed_dep,cc_lst_c) 331 332# Compile assembler sources (.S) 333# --------------------------------------------------------------------------- 334 335# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 336# or a file that it includes, in order to get versioned symbols. We build a 337# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 338# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 339# 340# This is convoluted. The .S file must first be preprocessed to run guards and 341# expand names, then the resulting exports must be constructed into plain 342# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 343# to make the genksyms input. 344# 345# These mirror gensymtypes_c and co above, keep them in synch. 346cmd_gensymtypes_S = \ 347 { echo "\#include <linux/kernel.h>" ; \ 348 echo "\#include <asm/asm-prototypes.h>" ; \ 349 $(CPP) $(a_flags) $< | \ 350 grep "\<___EXPORT_SYMBOL\>" | \ 351 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 352 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 353 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 354 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 355 $(if $(KBUILD_PRESERVE),-p) \ 356 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 357 358quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 359cmd_cc_symtypes_S = \ 360 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 361 test -s $@ || rm -f $@ 362 363$(obj)/%.symtypes : $(src)/%.S FORCE 364 $(call cmd,cc_symtypes_S) 365 366 367quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 368cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 369 370$(obj)/%.s: $(src)/%.S FORCE 371 $(call if_changed_dep,cpp_s_S) 372 373quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 374 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool) 375 376ifdef CONFIG_ASM_MODVERSIONS 377 378# versioning matches the C process described above, with difference that 379# we parse asm-prototypes.h C header to get function definitions. 380 381cmd_modversions_S = \ 382 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 383 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 384 > $(@D)/.tmp_$(@F:.o=.ver); \ 385 \ 386 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 387 -T $(@D)/.tmp_$(@F:.o=.ver); \ 388 mv -f $(@D)/.tmp_$(@F) $@; \ 389 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 390 fi 391endif 392 393$(obj)/%.o: $(src)/%.S FORCE 394 $(call if_changed_rule,as_o_S) 395 396targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 397targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 398targets += $(real-dtb-y) $(lib-y) $(always-y) $(MAKECMDGOALS) 399 400# Linker scripts preprocessor (.lds.S -> .lds) 401# --------------------------------------------------------------------------- 402quiet_cmd_cpp_lds_S = LDS $@ 403 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 404 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 405 406$(obj)/%.lds: $(src)/%.lds.S FORCE 407 $(call if_changed_dep,cpp_lds_S) 408 409# ASN.1 grammar 410# --------------------------------------------------------------------------- 411quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 412 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 413 $(basename $@).c $(basename $@).h 414 415$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 416 $(call cmd,asn1_compiler) 417 418# Build the compiled-in targets 419# --------------------------------------------------------------------------- 420 421# To build objects in subdirs, we need to descend into the directories 422$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 423$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 424 425# combine symversions for later processing 426ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y) 427 cmd_update_lto_symversions = \ 428 rm -f $@.symversions \ 429 $(foreach n, $(filter-out FORCE,$^), \ 430 $(if $(shell test -s $(n).symversions && echo y), \ 431 ; cat $(n).symversions >> $@.symversions)) 432else 433 cmd_update_lto_symversions = echo >/dev/null 434endif 435 436# 437# Rule to compile a set of .o files into one .a file (without symbol table) 438# 439 440quiet_cmd_ar_builtin = AR $@ 441 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) 442 443quiet_cmd_ar_and_symver = AR $@ 444 cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin) 445 446$(obj)/built-in.a: $(real-obj-y) FORCE 447 $(call if_changed,ar_and_symver) 448 449# 450# Rule to create modules.order file 451# 452# Create commands to either record .ko file or cat modules.order from 453# a subdirectory 454# Add $(obj-m) as the prerequisite to avoid updating the timestamp of 455# modules.order unless contained modules are updated. 456 457cmd_modules_order = { $(foreach m, $(real-prereqs), \ 458 $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \ 459 | $(AWK) '!x[$$0]++' - > $@ 460 461$(obj)/modules.order: $(obj-m) FORCE 462 $(call if_changed,modules_order) 463 464# 465# Rule to compile a set of .o files into one .a file (with symbol table) 466# 467quiet_cmd_ar_lib = AR $@ 468 cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar) 469 470$(obj)/lib.a: $(lib-y) FORCE 471 $(call if_changed,ar_lib) 472 473# NOTE: 474# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object 475# module is turned into a multi object module, $^ will contain header file 476# dependencies recorded in the .*.cmd file. 477ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) 478quiet_cmd_link_multi-m = AR [M] $@ 479cmd_link_multi-m = \ 480 $(cmd_update_lto_symversions); \ 481 rm -f $@; \ 482 $(AR) cDPrsT $@ $(filter %.o,$^) 483else 484quiet_cmd_link_multi-m = LD [M] $@ 485 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) 486endif 487 488$(multi-obj-m): FORCE 489 $(call if_changed,link_multi-m) 490$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 491 492targets += $(multi-obj-m) 493targets := $(filter-out $(PHONY), $(targets)) 494 495# Add intermediate targets: 496# When building objects with specific suffix patterns, add intermediate 497# targets that the final targets are derived from. 498intermediate_targets = $(foreach sfx, $(2), \ 499 $(patsubst %$(strip $(1)),%$(sfx), \ 500 $(filter %$(strip $(1)), $(targets)))) 501# %.asn1.o <- %.asn1.[ch] <- %.asn1 502# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 503# %.lex.o <- %.lex.c <- %.l 504# %.tab.o <- %.tab.[ch] <- %.y 505targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 506 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 507 $(call intermediate_targets, .lex.o, .lex.c) \ 508 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 509 510# Build 511# --------------------------------------------------------------------------- 512 513ifdef single-build 514 515KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS)) 516 517curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ 518 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) 519 520# Handle single targets without any rule: show "Nothing to be done for ..." or 521# "No rule to make target ..." depending on whether the target exists. 522unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ 523 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS))) 524 525single-subdirs := $(foreach d, $(subdir-ym), \ 526 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d))) 527 528__build: $(curdir-single) $(single-subdirs) 529ifneq ($(unknown-single),) 530 $(Q)$(MAKE) -f /dev/null $(unknown-single) 531endif 532 @: 533 534ifeq ($(curdir-single),) 535# Nothing to do in this directory. Do not include any .*.cmd file for speed-up 536targets := 537else 538targets += $(curdir-single) 539endif 540 541else 542 543__build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 544 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 545 $(subdir-ym) $(always-y) 546 @: 547 548endif 549 550# Descending 551# --------------------------------------------------------------------------- 552 553PHONY += $(subdir-ym) 554$(subdir-ym): 555 $(Q)$(MAKE) $(build)=$@ \ 556 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ 557 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 558 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) 559 560# Add FORCE to the prequisites of a target to force it to be always rebuilt. 561# --------------------------------------------------------------------------- 562 563PHONY += FORCE 564 565FORCE: 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 572existing-targets := $(wildcard $(sort $(targets))) 573 574-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 575 576# Create directories for object files if they do not exist 577obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 578# If targets exist, their directories apparently exist. Skip mkdir. 579existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 580obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 581ifneq ($(obj-dirs),) 582$(shell mkdir -p $(obj-dirs)) 583endif 584 585.PHONY: $(PHONY) 586