xref: /linux-6.15/scripts/Makefile.build (revision 265264b8)
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 := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m)))
90
91ifdef CONFIG_LTO_CLANG
92targets-for-modules += $(patsubst %.o, %.lto.o, $(filter %.o, $(obj-m)))
93endif
94
95ifdef need-modorder
96targets-for-modules += $(obj)/modules.order
97endif
98
99targets += $(targets-for-builtin) $(targets-for-modules)
100
101# Linus' kernel sanity checking tool
102ifeq ($(KBUILD_CHECKSRC),1)
103  quiet_cmd_checksrc       = CHECK   $<
104        cmd_checksrc       = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
105else ifeq ($(KBUILD_CHECKSRC),2)
106  quiet_cmd_force_checksrc = CHECK   $<
107        cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
108endif
109
110ifneq ($(KBUILD_EXTRA_WARN),)
111  cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
112endif
113
114# Compile C sources (.c)
115# ---------------------------------------------------------------------------
116
117quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
118      cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $<
119
120$(obj)/%.s: $(src)/%.c FORCE
121	$(call if_changed_dep,cc_s_c)
122
123quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
124cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
125
126$(obj)/%.i: $(src)/%.c FORCE
127	$(call if_changed_dep,cpp_i_c)
128
129# These mirror gensymtypes_S and co below, keep them in synch.
130cmd_gensymtypes_c =                                                         \
131    $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
132    scripts/genksyms/genksyms $(if $(1), -T $(2))                           \
133     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
134     $(if $(KBUILD_PRESERVE),-p)                                            \
135     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
136
137quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
138cmd_cc_symtypes_c =                                                         \
139    $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
140    test -s $@ || rm -f $@
141
142$(obj)/%.symtypes : $(src)/%.c FORCE
143	$(call cmd,cc_symtypes_c)
144
145# LLVM assembly
146# Generate .ll files from .c
147quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
148      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
149
150$(obj)/%.ll: $(src)/%.c FORCE
151	$(call if_changed_dep,cc_ll_c)
152
153# C (.c) files
154# The C file is compiled and updated dependency information is generated.
155# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
156
157quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
158      cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
159
160ifdef CONFIG_MODVERSIONS
161# When module versioning is enabled the following steps are executed:
162# o compile a <file>.o from <file>.c
163# o if <file>.o doesn't contain a __ksymtab version, i.e. does
164#   not export symbols, it's done.
165# o otherwise, we calculate symbol versions using the good old
166#   genksyms on the preprocessed source and postprocess them in a way
167#   that they are usable as a linker script
168# o generate .tmp_<file>.o from <file>.o using the linker to
169#   replace the unresolved symbols __crc_exported_symbol with
170#   the actual value of the checksum generated by genksyms
171# o remove .tmp_<file>.o to <file>.o
172
173ifdef CONFIG_LTO_CLANG
174# Generate .o.symversions files for each .o with exported symbols, and link these
175# to the kernel and/or modules at the end.
176cmd_modversions_c =								\
177	if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then			\
178		$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
179		    > $@.symversions;						\
180	fi;
181else
182cmd_modversions_c =								\
183	if $(OBJDUMP) -h $@ | grep -q __ksymtab; then				\
184		$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
185		    > $(@D)/.tmp_$(@F:.o=.ver);					\
186										\
187		$(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ 		\
188			-T $(@D)/.tmp_$(@F:.o=.ver);				\
189		mv -f $(@D)/.tmp_$(@F) $@;					\
190		rm -f $(@D)/.tmp_$(@F:.o=.ver);					\
191	fi
192endif
193endif
194
195ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
196# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
197ifdef BUILD_C_RECORDMCOUNT
198ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
199  RECORDMCOUNT_FLAGS = -w
200endif
201# Due to recursion, we must skip empty.o.
202# The empty.o file is created in the make process in order to determine
203# the target endianness and word size. It is made before all other C
204# files, including recordmcount.
205sub_cmd_record_mcount =					\
206	if [ $(@) != "scripts/mod/empty.o" ]; then	\
207		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\
208	fi;
209recordmcount_source := $(srctree)/scripts/recordmcount.c \
210		    $(srctree)/scripts/recordmcount.h
211else
212sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
213	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
214	"$(if $(CONFIG_64BIT),64,32)" \
215	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
216	"$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
217	"$(if $(part-of-module),1,0)" "$(@)";
218recordmcount_source := $(srctree)/scripts/recordmcount.pl
219endif # BUILD_C_RECORDMCOUNT
220cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),	\
221	$(sub_cmd_record_mcount))
222endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
223
224ifdef CONFIG_STACK_VALIDATION
225ifndef CONFIG_LTO_CLANG
226
227__objtool_obj := $(objtree)/tools/objtool/objtool
228
229# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
230# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
231# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
232cmd_objtool = $(if $(patsubst y%,, \
233	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
234	$(__objtool_obj) $(objtool_args) $@)
235objtool_obj = $(if $(patsubst y%,, \
236	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
237	$(__objtool_obj))
238
239endif # CONFIG_LTO_CLANG
240endif # CONFIG_STACK_VALIDATION
241
242# Rebuild all objects when objtool changes, or is enabled/disabled.
243objtool_dep = $(objtool_obj)					\
244	      $(wildcard include/config/ORC_UNWINDER		\
245			 include/config/STACK_VALIDATION)
246
247ifdef CONFIG_TRIM_UNUSED_KSYMS
248cmd_gen_ksymdeps = \
249	$(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
250
251# List module undefined symbols
252undefined_syms = $(NM) $< | $(AWK) '$$1 == "U" { printf("%s%s", x++ ? " " : "", $$2) }';
253endif
254
255define rule_cc_o_c
256	$(call cmd_and_fixdep,cc_o_c)
257	$(call cmd,gen_ksymdeps)
258	$(call cmd,checksrc)
259	$(call cmd,checkdoc)
260	$(call cmd,objtool)
261	$(call cmd,modversions_c)
262	$(call cmd,record_mcount)
263endef
264
265define rule_as_o_S
266	$(call cmd_and_fixdep,as_o_S)
267	$(call cmd,gen_ksymdeps)
268	$(call cmd,objtool)
269	$(call cmd,modversions_S)
270endef
271
272# Built-in and composite module parts
273.SECONDEXPANSION:
274$(obj)/%.o: $(src)/%.c $(recordmcount_source) $$(objtool_dep) FORCE
275	$(call if_changed_rule,cc_o_c)
276	$(call cmd,force_checksrc)
277
278ifdef CONFIG_LTO_CLANG
279# Module .o files may contain LLVM bitcode, compile them into native code
280# before ELF processing
281quiet_cmd_cc_lto_link_modules = LTO [M] $@
282cmd_cc_lto_link_modules =						\
283	$(LD) $(ld_flags) -r -o $@					\
284		$(shell [ -s $(@:.lto.o=.o.symversions) ] &&		\
285			echo -T $(@:.lto.o=.o.symversions))		\
286		--whole-archive $(filter-out FORCE,$^)
287
288ifdef CONFIG_STACK_VALIDATION
289# objtool was skipped for LLVM bitcode, run it now that we have compiled
290# modules into native code
291cmd_cc_lto_link_modules += ;						\
292	$(objtree)/tools/objtool/objtool $(objtool_args) --module $@
293endif
294
295$(obj)/%.lto.o: $(obj)/%.o FORCE
296	$(call if_changed,cc_lto_link_modules)
297endif
298
299cmd_mod = { \
300	echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
301	$(undefined_syms) echo; \
302	} > $@
303
304$(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE
305	$(call if_changed,mod)
306
307quiet_cmd_cc_lst_c = MKLST   $@
308      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
309		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
310				     System.map $(OBJDUMP) > $@
311
312$(obj)/%.lst: $(src)/%.c FORCE
313	$(call if_changed_dep,cc_lst_c)
314
315# Compile assembler sources (.S)
316# ---------------------------------------------------------------------------
317
318# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
319# or a file that it includes, in order to get versioned symbols. We build a
320# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
321# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
322#
323# This is convoluted. The .S file must first be preprocessed to run guards and
324# expand names, then the resulting exports must be constructed into plain
325# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
326# to make the genksyms input.
327#
328# These mirror gensymtypes_c and co above, keep them in synch.
329cmd_gensymtypes_S =                                                         \
330   { echo "\#include <linux/kernel.h>" ;                                    \
331     echo "\#include <asm/asm-prototypes.h>" ;                              \
332    $(CPP) $(a_flags) $< |                                                  \
333     grep "\<___EXPORT_SYMBOL\>" |                                          \
334     sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
335    $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
336    scripts/genksyms/genksyms $(if $(1), -T $(2))                           \
337     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
338     $(if $(KBUILD_PRESERVE),-p)                                            \
339     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
340
341quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
342cmd_cc_symtypes_S =                                                         \
343    $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
344    test -s $@ || rm -f $@
345
346$(obj)/%.symtypes : $(src)/%.S FORCE
347	$(call cmd,cc_symtypes_S)
348
349
350quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
351cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
352
353$(obj)/%.s: $(src)/%.S FORCE
354	$(call if_changed_dep,cpp_s_S)
355
356quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
357      cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
358
359ifdef CONFIG_ASM_MODVERSIONS
360
361# versioning matches the C process described above, with difference that
362# we parse asm-prototypes.h C header to get function definitions.
363
364cmd_modversions_S =								\
365	if $(OBJDUMP) -h $@ | grep -q __ksymtab; then				\
366		$(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
367		    > $(@D)/.tmp_$(@F:.o=.ver);					\
368										\
369		$(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ 		\
370			-T $(@D)/.tmp_$(@F:.o=.ver);				\
371		mv -f $(@D)/.tmp_$(@F) $@;					\
372		rm -f $(@D)/.tmp_$(@F:.o=.ver);					\
373	fi
374endif
375
376$(obj)/%.o: $(src)/%.S $$(objtool_dep) FORCE
377	$(call if_changed_rule,as_o_S)
378
379targets += $(filter-out $(subdir-builtin), $(real-obj-y))
380targets += $(filter-out $(subdir-modorder), $(real-obj-m))
381targets += $(real-dtb-y) $(lib-y) $(always-y) $(MAKECMDGOALS)
382
383# Linker scripts preprocessor (.lds.S -> .lds)
384# ---------------------------------------------------------------------------
385quiet_cmd_cpp_lds_S = LDS     $@
386      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
387	                     -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
388
389$(obj)/%.lds: $(src)/%.lds.S FORCE
390	$(call if_changed_dep,cpp_lds_S)
391
392# ASN.1 grammar
393# ---------------------------------------------------------------------------
394quiet_cmd_asn1_compiler = ASN.1   $(basename $@).[ch]
395      cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
396				$(basename $@).c $(basename $@).h
397
398$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
399	$(call cmd,asn1_compiler)
400
401# Build the compiled-in targets
402# ---------------------------------------------------------------------------
403
404# To build objects in subdirs, we need to descend into the directories
405$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;
406$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
407
408# combine symversions for later processing
409quiet_cmd_update_lto_symversions = SYMVER  $@
410ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y)
411      cmd_update_lto_symversions =					\
412	rm -f $@.symversions						\
413	$(foreach n, $(filter-out FORCE,$^),				\
414		$(if $(shell test -s $(n).symversions && echo y),	\
415			; cat $(n).symversions >> $@.symversions))
416else
417      cmd_update_lto_symversions = echo >/dev/null
418endif
419
420#
421# Rule to compile a set of .o files into one .a file (without symbol table)
422#
423
424quiet_cmd_ar_builtin = AR      $@
425      cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs)
426
427quiet_cmd_ar_and_symver = AR      $@
428      cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin)
429
430$(obj)/built-in.a: $(real-obj-y) FORCE
431	$(call if_changed,ar_and_symver)
432
433#
434# Rule to create modules.order file
435#
436# Create commands to either record .ko file or cat modules.order from
437# a subdirectory
438# Add $(obj-m) as the prerequisite to avoid updating the timestamp of
439# modules.order unless contained modules are updated.
440
441cmd_modules_order = { $(foreach m, $(real-prereqs), \
442	$(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \
443	| $(AWK) '!x[$$0]++' - > $@
444
445$(obj)/modules.order: $(obj-m) FORCE
446	$(call if_changed,modules_order)
447
448#
449# Rule to compile a set of .o files into one .a file (with symbol table)
450#
451quiet_cmd_ar_lib = AR      $@
452      cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar)
453
454$(obj)/lib.a: $(lib-y) FORCE
455	$(call if_changed,ar_lib)
456
457# NOTE:
458# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
459# module is turned into a multi object module, $^ will contain header file
460# dependencies recorded in the .*.cmd file.
461ifdef CONFIG_LTO_CLANG
462quiet_cmd_link_multi-m = AR [M]  $@
463cmd_link_multi-m =						\
464	$(cmd_update_lto_symversions);				\
465	rm -f $@; 						\
466	$(AR) cDPrsT $@ $(filter %.o,$^)
467else
468quiet_cmd_link_multi-m = LD [M]  $@
469      cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
470endif
471
472$(multi-obj-m): FORCE
473	$(call if_changed,link_multi-m)
474$(call multi_depend, $(multi-obj-m), .o, -objs -y -m)
475
476targets += $(multi-obj-m)
477targets := $(filter-out $(PHONY), $(targets))
478
479# Add intermediate targets:
480# When building objects with specific suffix patterns, add intermediate
481# targets that the final targets are derived from.
482intermediate_targets = $(foreach sfx, $(2), \
483				$(patsubst %$(strip $(1)),%$(sfx), \
484					$(filter %$(strip $(1)), $(targets))))
485# %.asn1.o <- %.asn1.[ch] <- %.asn1
486# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
487# %.lex.o <- %.lex.c <- %.l
488# %.tab.o <- %.tab.[ch] <- %.y
489targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
490	   $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
491	   $(call intermediate_targets, .lex.o, .lex.c) \
492	   $(call intermediate_targets, .tab.o, .tab.c .tab.h)
493
494# Build
495# ---------------------------------------------------------------------------
496
497ifdef single-build
498
499KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS))
500
501curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \
502			$(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x))))
503
504# Handle single targets without any rule: show "Nothing to be done for ..." or
505# "No rule to make target ..." depending on whether the target exists.
506unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \
507			$(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS)))
508
509single-subdirs := $(foreach d, $(subdir-ym), \
510			$(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d)))
511
512__build: $(curdir-single) $(single-subdirs)
513ifneq ($(unknown-single),)
514	$(Q)$(MAKE) -f /dev/null $(unknown-single)
515endif
516	@:
517
518ifeq ($(curdir-single),)
519# Nothing to do in this directory. Do not include any .*.cmd file for speed-up
520targets :=
521else
522targets += $(curdir-single)
523endif
524
525else
526
527__build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \
528	 $(if $(KBUILD_MODULES), $(targets-for-modules)) \
529	 $(subdir-ym) $(always-y)
530	@:
531
532endif
533
534# Descending
535# ---------------------------------------------------------------------------
536
537PHONY += $(subdir-ym)
538$(subdir-ym):
539	$(Q)$(MAKE) $(build)=$@ \
540	$(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
541	need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \
542	need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1)
543
544# Add FORCE to the prequisites of a target to force it to be always rebuilt.
545# ---------------------------------------------------------------------------
546
547PHONY += FORCE
548
549FORCE:
550
551# Read all saved command lines and dependencies for the $(targets) we
552# may be building above, using $(if_changed{,_dep}). As an
553# optimization, we don't need to read them if the target does not
554# exist, we will rebuild anyway in that case.
555
556existing-targets := $(wildcard $(sort $(targets)))
557
558-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
559
560# Create directories for object files if they do not exist
561obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets))))
562# If targets exist, their directories apparently exist. Skip mkdir.
563existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
564obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
565ifneq ($(obj-dirs),)
566$(shell mkdir -p $(obj-dirs))
567endif
568
569.PHONY: $(PHONY)
570