1# SPDX-License-Identifier: GPL-2.0 2# ========================================================================== 3# Building 4# ========================================================================== 5 6src := $(srcroot)/$(obj) 7 8PHONY := $(obj)/ 9$(obj)/: 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 := 23asflags-y := 24ccflags-y := 25rustflags-y := 26cppflags-y := 27ldflags-y := 28 29subdir-asflags-y := 30subdir-ccflags-y := 31 32# Read auto.conf if it exists, otherwise ignore 33-include $(objtree)/include/config/auto.conf 34 35include $(srctree)/scripts/Kbuild.include 36include $(srctree)/scripts/Makefile.compiler 37include $(kbuild-file) 38include $(srctree)/scripts/Makefile.lib 39 40# flags that take effect in current and sub directories 41KBUILD_AFLAGS += $(subdir-asflags-y) 42KBUILD_CFLAGS += $(subdir-ccflags-y) 43KBUILD_RUSTFLAGS += $(subdir-rustflags-y) 44 45# Figure out what we need to build from the various variables 46# =========================================================================== 47 48# When an object is listed to be built compiled-in and modular, 49# only build the compiled-in version 50obj-m := $(filter-out $(obj-y),$(obj-m)) 51 52# Libraries are always collected in one lib file. 53# Filter out objects already built-in 54lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m))) 55 56# Subdirectories we need to descend into 57subdir-ym := $(sort $(subdir-y) $(subdir-m) \ 58 $(patsubst %/,%, $(filter %/, $(obj-y) $(obj-m)))) 59 60# Handle objects in subdirs: 61# - If we encounter foo/ in $(obj-y), replace it by foo/built-in.a and 62# foo/modules.order 63# - If we encounter foo/ in $(obj-m), replace it by foo/modules.order 64# 65# Generate modules.order to determine modorder. Unfortunately, we don't have 66# information about ordering between -y and -m subdirs. Just put -y's first. 67 68ifdef need-modorder 69obj-m := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m)) 70else 71obj-m := $(filter-out %/, $(obj-m)) 72endif 73 74ifdef need-builtin 75obj-y := $(patsubst %/, %/built-in.a, $(obj-y)) 76else 77obj-y := $(filter-out %/, $(obj-y)) 78endif 79 80# Expand $(foo-objs) $(foo-y) etc. by replacing their individuals 81suffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s)))) 82# List composite targets that are constructed by combining other targets 83multi-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $m))) 84# List primitive targets that are compiled from source files 85real-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $(call suffix-search, $m, $2, $3), $m)) 86 87# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object 88multi-obj-y := $(call multi-search, $(obj-y), .o, -objs -y) 89multi-obj-m := $(call multi-search, $(obj-m), .o, -objs -y -m) 90multi-obj-ym := $(multi-obj-y) $(multi-obj-m) 91 92# Replace multi-part objects by their individual parts, 93# including built-in.a from subdirectories 94real-obj-y := $(call real-search, $(obj-y), .o, -objs -y) 95real-obj-m := $(call real-search, $(obj-m), .o, -objs -y -m) 96 97always-y += $(always-m) 98 99# hostprogs-always-y += foo 100# ... is a shorthand for 101# hostprogs += foo 102# always-y += foo 103hostprogs += $(hostprogs-always-y) $(hostprogs-always-m) 104always-y += $(hostprogs-always-y) $(hostprogs-always-m) 105 106# userprogs-always-y is likewise. 107userprogs += $(userprogs-always-y) $(userprogs-always-m) 108always-y += $(userprogs-always-y) $(userprogs-always-m) 109 110# Add subdir path 111 112ifneq ($(obj),.) 113extra-y := $(addprefix $(obj)/, $(extra-y)) 114always-y := $(addprefix $(obj)/, $(always-y)) 115targets := $(addprefix $(obj)/, $(targets)) 116obj-m := $(addprefix $(obj)/, $(obj-m)) 117lib-y := $(addprefix $(obj)/, $(lib-y)) 118real-obj-y := $(addprefix $(obj)/, $(real-obj-y)) 119real-obj-m := $(addprefix $(obj)/, $(real-obj-m)) 120multi-obj-m := $(addprefix $(obj)/, $(multi-obj-m)) 121subdir-ym := $(addprefix $(obj)/, $(subdir-ym)) 122endif 123 124ifndef obj 125$(warning kbuild: Makefile.build is included improperly) 126endif 127 128ifeq ($(need-modorder),) 129ifneq ($(obj-m),) 130$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 131$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 132endif 133endif 134 135# =========================================================================== 136 137# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...) 138subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y))) 139subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) 140 141targets-for-builtin := $(extra-y) 142 143ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 144targets-for-builtin += $(obj)/lib.a 145endif 146 147ifdef need-builtin 148targets-for-builtin += $(obj)/built-in.a 149endif 150 151targets-for-modules := $(foreach x, o mod, \ 152 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) 153 154ifdef need-modorder 155targets-for-modules += $(obj)/modules.order 156endif 157 158targets += $(targets-for-builtin) $(targets-for-modules) 159 160# Linus' kernel sanity checking tool 161ifeq ($(KBUILD_CHECKSRC),1) 162 quiet_cmd_checksrc = CHECK $< 163 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 164else ifeq ($(KBUILD_CHECKSRC),2) 165 quiet_cmd_force_checksrc = CHECK $< 166 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 167endif 168 169ifneq ($(KBUILD_EXTRA_WARN),) 170 cmd_checkdoc = PYTHONDONTWRITEBYTECODE=1 $(KERNELDOC) -none $(KDOCFLAGS) \ 171 $(if $(findstring 2, $(KBUILD_EXTRA_WARN)), -Wall) \ 172 $< 173endif 174 175# Compile C sources (.c) 176# --------------------------------------------------------------------------- 177 178quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 179 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< 180 181$(obj)/%.s: $(obj)/%.c FORCE 182 $(call if_changed_dep,cc_s_c) 183 184quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 185cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 186 187$(obj)/%.i: $(obj)/%.c FORCE 188 $(call if_changed_dep,cpp_i_c) 189 190getexportsymbols = $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/$(1)/p' 191 192gendwarfksyms = $(objtree)/scripts/gendwarfksyms/gendwarfksyms \ 193 $(if $(KBUILD_SYMTYPES), --symtypes $(@:.o=.symtypes)) \ 194 $(if $(KBUILD_GENDWARFKSYMS_STABLE), --stable) 195 196genksyms = $(objtree)/scripts/genksyms/genksyms \ 197 $(if $(KBUILD_SYMTYPES), -T $(@:.o=.symtypes)) \ 198 $(if $(KBUILD_PRESERVE), -p) \ 199 $(addprefix -r , $(wildcard $(@:.o=.symref))) 200 201# These mirror gensymtypes_S and co below, keep them in synch. 202ifdef CONFIG_GENDWARFKSYMS 203cmd_gensymtypes_c = $(if $(skip_gendwarfksyms),, \ 204 $(call getexportsymbols,\1) | $(gendwarfksyms) $@) 205else 206cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) 207endif # CONFIG_GENDWARFKSYMS 208 209# LLVM assembly 210# Generate .ll files from .c 211quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 212 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $< 213 214$(obj)/%.ll: $(obj)/%.c FORCE 215 $(call if_changed_dep,cc_ll_c) 216 217# C (.c) files 218# The C file is compiled and updated dependency information is generated. 219# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 220 221is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) 222 223ifdef CONFIG_MODVERSIONS 224# When module versioning is enabled the following steps are executed: 225# o compile a <file>.o from <file>.c 226# o if <file>.o doesn't contain a __export_symbol_*, i.e. does 227# not export symbols, it's done. 228# o otherwise, we calculate symbol versions using the good old 229# genksyms on the preprocessed source and dump them into the .cmd file. 230# o modpost will extract versions from that file and create *.c files that will 231# be compiled and linked to the kernel and/or modules. 232 233gen_symversions = \ 234 if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then \ 235 $(cmd_gensymtypes_$1) >> $(dot-target).cmd; \ 236 fi 237 238cmd_gen_symversions_c = $(call gen_symversions,c) 239 240endif 241 242ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 243# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 244ifdef BUILD_C_RECORDMCOUNT 245ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 246 RECORDMCOUNT_FLAGS = -w 247endif 248# Due to recursion, we must skip empty.o. 249# The empty.o file is created in the make process in order to determine 250# the target endianness and word size. It is made before all other C 251# files, including recordmcount. 252sub_cmd_record_mcount = \ 253 if [ $(@) != "scripts/mod/empty.o" ]; then \ 254 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 255 fi; 256recordmcount_source := $(srctree)/scripts/recordmcount.c \ 257 $(srctree)/scripts/recordmcount.h 258else 259sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 260 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 261 "$(if $(CONFIG_64BIT),64,32)" \ 262 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 263 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 264 "$(if $(part-of-module),1,0)" "$(@)"; 265recordmcount_source := $(srctree)/scripts/recordmcount.pl 266endif # BUILD_C_RECORDMCOUNT 267cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 268 $(sub_cmd_record_mcount)) 269endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 270 271# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 272# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 273# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 274 275is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),$(is-kernel-object)) 276 277ifdef CONFIG_OBJTOOL 278$(obj)/%.o: private objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) 279endif 280 281ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) 282cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) 283endif 284 285# Built-in and composite module parts 286$(obj)/%.o: $(obj)/%.c $(recordmcount_source) FORCE 287 $(call if_changed_rule,cc_o_c) 288 $(call cmd,force_checksrc) 289 290# To make this rule robust against "Argument list too long" error, 291# ensure to add $(obj)/ prefix by a shell command. 292cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ 293 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ 294 295$(obj)/%.mod: FORCE 296 $(call if_changed,mod) 297 298quiet_cmd_cc_lst_c = MKLST $@ 299 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 300 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 301 System.map $(OBJDUMP) > $@ 302 303$(obj)/%.lst: $(obj)/%.c FORCE 304 $(call if_changed_dep,cc_lst_c) 305 306# Compile Rust sources (.rs) 307# --------------------------------------------------------------------------- 308 309# The features in this list are the ones allowed for non-`rust/` code. 310# 311# - Stable since Rust 1.81.0: `feature(lint_reasons)`. 312# - Stable since Rust 1.82.0: `feature(asm_const)`, `feature(raw_ref_op)`. 313# - Stable since Rust 1.87.0: `feature(asm_goto)`. 314# - Expected to become stable: `feature(arbitrary_self_types)`. 315# - To be determined: `feature(used_with_arg)`. 316# 317# Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on 318# the unstable features in use. 319rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,raw_ref_op,used_with_arg 320 321# `--out-dir` is required to avoid temporaries being created by `rustc` in the 322# current working directory, which may be not accessible in the out-of-tree 323# modules case. 324rust_common_cmd = \ 325 OBJTREE=$(abspath $(objtree)) \ 326 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ 327 -Zallow-features=$(rust_allowed_features) \ 328 -Zcrate-attr=no_std \ 329 -Zcrate-attr='feature($(rust_allowed_features))' \ 330 -Zunstable-options --extern pin_init --extern kernel \ 331 --crate-type rlib -L $(objtree)/rust/ \ 332 --crate-name $(basename $(notdir $@)) \ 333 --sysroot=/dev/null \ 334 --out-dir $(dir $@) --emit=dep-info=$(depfile) 335 336# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit 337# will be used. We explicitly request `-Ccodegen-units=1` in any case, and 338# the compiler shows a warning if it is not 1. However, if we ever stop 339# requesting it explicitly and we start using some other `--emit` that does not 340# imply it (and for which codegen is performed), then we would be out of sync, 341# i.e. the outputs we would get for the different single targets (e.g. `.ll`) 342# would not match each other. 343 344quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 345 cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< $(cmd_objtool) 346 347define rule_rustc_o_rs 348 $(call cmd_and_fixdep,rustc_o_rs) 349 $(call cmd,gen_objtooldep) 350endef 351 352$(obj)/%.o: $(obj)/%.rs FORCE 353 +$(call if_changed_rule,rustc_o_rs) 354 355quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 356 cmd_rustc_rsi_rs = \ 357 $(rust_common_cmd) -Zunpretty=expanded $< >$@; \ 358 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@ 359 360$(obj)/%.rsi: $(obj)/%.rs FORCE 361 +$(call if_changed_dep,rustc_rsi_rs) 362 363quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 364 cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $< 365 366$(obj)/%.s: $(obj)/%.rs FORCE 367 +$(call if_changed_dep,rustc_s_rs) 368 369quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 370 cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $< 371 372$(obj)/%.ll: $(obj)/%.rs FORCE 373 +$(call if_changed_dep,rustc_ll_rs) 374 375quiet_cmd_rustc_rs_rs_S = RSCPP $(quiet_modtag) $@ 376 cmd_rustc_rs_rs_S = $(CPP) $(c_flags) -xc -C -P $< | sed '1,/^\/\/ Cut here.$$/d' >$@ 377 378$(obj)/%.rs: $(obj)/%.rs.S FORCE 379 +$(call if_changed_dep,rustc_rs_rs_S) 380 381# Compile assembler sources (.S) 382# --------------------------------------------------------------------------- 383 384# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 385# or a file that it includes, in order to get versioned symbols. We build a 386# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 387# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 388# 389# This is convoluted. The .S file must first be preprocessed to run guards and 390# expand names, then the resulting exports must be constructed into plain 391# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 392# to make the genksyms input or compiled into an object for gendwarfksyms. 393# 394# These mirror gensymtypes_c and co above, keep them in synch. 395getasmexports = \ 396 { echo "\#include <linux/kernel.h>" ; \ 397 echo "\#include <linux/string.h>" ; \ 398 echo "\#include <asm/asm-prototypes.h>" ; \ 399 $(call getexportsymbols,EXPORT_SYMBOL(\1);) ; } 400 401ifdef CONFIG_GENDWARFKSYMS 402cmd_gensymtypes_S = \ 403 $(getasmexports) | \ 404 $(CC) $(c_flags) -c -o $(@:.o=.gendwarfksyms.o) -xc -; \ 405 $(call getexportsymbols,\1) | \ 406 $(gendwarfksyms) $(@:.o=.gendwarfksyms.o) 407else 408cmd_gensymtypes_S = \ 409 $(getasmexports) | \ 410 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) 411endif # CONFIG_GENDWARFKSYMS 412 413quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 414cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 415 416$(obj)/%.s: $(obj)/%.S FORCE 417 $(call if_changed_dep,cpp_s_S) 418 419ifdef CONFIG_ASM_MODVERSIONS 420 421# versioning matches the C process described above, with difference that 422# we parse asm-prototypes.h C header to get function definitions. 423 424cmd_gen_symversions_S = $(call gen_symversions,S) 425 426endif 427 428$(obj)/%.o: $(obj)/%.S FORCE 429 $(call if_changed_rule,as_o_S) 430 431targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 432targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 433targets += $(lib-y) $(always-y) 434 435# Linker scripts preprocessor (.lds.S -> .lds) 436# --------------------------------------------------------------------------- 437quiet_cmd_cpp_lds_S = LDS $@ 438 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 439 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 440 441$(obj)/%.lds: $(src)/%.lds.S FORCE 442 $(call if_changed_dep,cpp_lds_S) 443 444# ASN.1 grammar 445# --------------------------------------------------------------------------- 446quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 447 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 448 $(basename $@).c $(basename $@).h 449 450$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 451 $(call cmd,asn1_compiler) 452 453# Build the compiled-in targets 454# --------------------------------------------------------------------------- 455 456# To build objects in subdirs, we need to descend into the directories 457$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 458$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 459 460# 461# Rule to compile a set of .o files into one .a file (without symbol table) 462# 463# To make this rule robust against "Argument list too long" error, 464# remove $(obj)/ prefix, and restore it by a shell command. 465 466quiet_cmd_ar_builtin = AR $@ 467 cmd_ar_builtin = rm -f $@; \ 468 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \ 469 $(AR) cDPrST $@ 470 471$(obj)/built-in.a: $(real-obj-y) FORCE 472 $(call if_changed,ar_builtin) 473 474# This is a list of build artifacts from the current Makefile and its 475# sub-directories. The timestamp should be updated when any of the member files. 476 477cmd_gen_order = { $(foreach m, $(real-prereqs), \ 478 $(if $(filter %/$(notdir $@), $m), cat $m, echo $m);) :; } \ 479 > $@ 480 481$(obj)/modules.order: $(obj-m) FORCE 482 $(call if_changed,gen_order) 483 484# 485# Rule to compile a set of .o files into one .a file (with symbol table) 486# 487 488$(obj)/lib.a: $(lib-y) FORCE 489 $(call if_changed,ar) 490 491quiet_cmd_ld_multi_m = LD [M] $@ 492 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$< $(cmd_objtool) 493 494define rule_ld_multi_m 495 $(call cmd_and_savecmd,ld_multi_m) 496 $(call cmd,gen_objtooldep) 497endef 498 499$(multi-obj-m): private objtool-enabled := $(delay-objtool) 500$(multi-obj-m): private part-of-module := y 501$(multi-obj-m): %.o: %.mod FORCE 502 $(call if_changed_rule,ld_multi_m) 503$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 504 505# Add intermediate targets: 506# When building objects with specific suffix patterns, add intermediate 507# targets that the final targets are derived from. 508intermediate_targets = $(foreach sfx, $(2), \ 509 $(patsubst %$(strip $(1)),%$(sfx), \ 510 $(filter %$(strip $(1)), $(targets)))) 511# %.asn1.o <- %.asn1.[ch] <- %.asn1 512targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) 513 514# Include additional build rules when necessary 515# --------------------------------------------------------------------------- 516 517# $(sort ...) is used here to remove duplicated words and excessive spaces. 518hostprogs := $(sort $(hostprogs)) 519ifneq ($(hostprogs),) 520include $(srctree)/scripts/Makefile.host 521endif 522 523# $(sort ...) is used here to remove duplicated words and excessive spaces. 524userprogs := $(sort $(userprogs)) 525ifneq ($(userprogs),) 526include $(srctree)/scripts/Makefile.userprogs 527endif 528 529ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets)),) 530include $(srctree)/scripts/Makefile.dtbs 531endif 532 533# Build 534# --------------------------------------------------------------------------- 535 536$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 537 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 538 $(subdir-ym) $(always-y) 539 @: 540 541# Single targets 542# --------------------------------------------------------------------------- 543 544single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d)) 545single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS)) 546 547$(single-subdir-goals): $(single-subdirs) 548 @: 549 550# Descending 551# --------------------------------------------------------------------------- 552 553PHONY += $(subdir-ym) 554$(subdir-ym): 555 $(Q)$(MAKE) $(build)=$@ \ 556 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 557 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \ 558 $(filter $@/%, $(single-subdir-goals)) 559 560# Add FORCE to the prerequisites of a target to force it to be always rebuilt. 561# --------------------------------------------------------------------------- 562 563PHONY += FORCE 564 565FORCE: 566 567targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS)) 568targets := $(filter-out $(PHONY), $(targets)) 569 570# Read all saved command lines and dependencies for the $(targets) we 571# may be building above, using $(if_changed{,_dep}). As an 572# optimization, we don't need to read them if the target does not 573# exist, we will rebuild anyway in that case. 574 575existing-targets := $(wildcard $(sort $(targets))) 576 577-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 578 579# Create directories for object files if they do not exist 580obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 581# If targets exist, their directories apparently exist. Skip mkdir. 582existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 583obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 584ifneq ($(obj-dirs),) 585$(shell mkdir -p $(obj-dirs)) 586endif 587 588.PHONY: $(PHONY) 589