Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
56# Do not include host rules unless needed
57ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
58include scripts/Makefile.host
59endif
60
61ifndef obj
62$(warning kbuild: Makefile.build is included improperly)
63endif
64
65# ===========================================================================
66
67ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
68lib-target := $(obj)/lib.a
69real-obj-y += $(obj)/lib-ksyms.o
70endif
71
72ifneq ($(strip $(real-obj-y) $(need-builtin)),)
73builtin-target := $(obj)/built-in.a
74endif
75
76modorder-target := $(obj)/modules.order
77
78# We keep a list of all modules in $(MODVERDIR)
79
80__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
81 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
82 $(subdir-ym) $(always)
83 @:
84
85# Linus' kernel sanity checking tool
86ifneq ($(KBUILD_CHECKSRC),0)
87 ifeq ($(KBUILD_CHECKSRC),2)
88 quiet_cmd_force_checksrc = CHECK $<
89 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
90 else
91 quiet_cmd_checksrc = CHECK $<
92 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
93 endif
94endif
95
96ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
97 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< ;
98endif
99
100# Do section mismatch analysis for each module/built-in.a
101ifdef CONFIG_DEBUG_SECTION_MISMATCH
102 cmd_secanalysis = ; scripts/mod/modpost $@
103endif
104
105# Compile C sources (.c)
106# ---------------------------------------------------------------------------
107
108# Default is built-in, unless we know otherwise
109modkern_cflags = \
110 $(if $(part-of-module), \
111 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
112 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
113quiet_modtag := $(empty) $(empty)
114
115$(real-obj-m) : part-of-module := y
116$(real-obj-m:.o=.i) : part-of-module := y
117$(real-obj-m:.o=.s) : part-of-module := y
118$(real-obj-m:.o=.lst): part-of-module := y
119
120$(real-obj-m) : quiet_modtag := [M]
121$(real-obj-m:.o=.i) : quiet_modtag := [M]
122$(real-obj-m:.o=.s) : quiet_modtag := [M]
123$(real-obj-m:.o=.lst): quiet_modtag := [M]
124
125$(obj-m) : quiet_modtag := [M]
126
127quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
128cmd_cc_s_c = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
129
130$(obj)/%.s: $(src)/%.c FORCE
131 $(call if_changed_dep,cc_s_c)
132
133quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
134cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
135
136$(obj)/%.i: $(src)/%.c FORCE
137 $(call if_changed_dep,cpp_i_c)
138
139# These mirror gensymtypes_S and co below, keep them in synch.
140cmd_gensymtypes_c = \
141 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
142 $(GENKSYMS) $(if $(1), -T $(2)) \
143 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
144 $(if $(KBUILD_PRESERVE),-p) \
145 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
146
147quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
148cmd_cc_symtypes_c = \
149 set -e; \
150 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \
151 test -s $@ || rm -f $@
152
153$(obj)/%.symtypes : $(src)/%.c FORCE
154 $(call cmd,cc_symtypes_c)
155
156# LLVM assembly
157# Generate .ll files from .c
158quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
159 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
160
161$(obj)/%.ll: $(src)/%.c FORCE
162 $(call if_changed_dep,cc_ll_c)
163
164# C (.c) files
165# The C file is compiled and updated dependency information is generated.
166# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
167
168quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
169
170ifndef CONFIG_MODVERSIONS
171cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
172
173else
174# When module versioning is enabled the following steps are executed:
175# o compile a .tmp_<file>.o from <file>.c
176# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
177# not export symbols, we just rename .tmp_<file>.o to <file>.o and
178# are done.
179# o otherwise, we calculate symbol versions using the good old
180# genksyms on the preprocessed source and postprocess them in a way
181# that they are usable as a linker script
182# o generate <file>.o from .tmp_<file>.o using the linker to
183# replace the unresolved symbols __crc_exported_symbol with
184# the actual value of the checksum generated by genksyms
185
186cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
187
188cmd_modversions_c = \
189 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
190 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
191 > $(@D)/.tmp_$(@F:.o=.ver); \
192 \
193 $(LD) $(KBUILD_LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
194 -T $(@D)/.tmp_$(@F:.o=.ver); \
195 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
196 else \
197 mv -f $(@D)/.tmp_$(@F) $@; \
198 fi;
199endif
200
201ifdef CONFIG_FTRACE_MCOUNT_RECORD
202ifndef CC_USING_RECORD_MCOUNT
203# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
204ifdef BUILD_C_RECORDMCOUNT
205ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
206 RECORDMCOUNT_FLAGS = -w
207endif
208# Due to recursion, we must skip empty.o.
209# The empty.o file is created in the make process in order to determine
210# the target endianness and word size. It is made before all other C
211# files, including recordmcount.
212sub_cmd_record_mcount = \
213 if [ $(@) != "scripts/mod/empty.o" ]; then \
214 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
215 fi;
216recordmcount_source := $(srctree)/scripts/recordmcount.c \
217 $(srctree)/scripts/recordmcount.h
218else
219sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
220 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
221 "$(if $(CONFIG_64BIT),64,32)" \
222 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
223 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
224 "$(if $(part-of-module),1,0)" "$(@)";
225recordmcount_source := $(srctree)/scripts/recordmcount.pl
226endif # BUILD_C_RECORDMCOUNT
227cmd_record_mcount = \
228 if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" = \
229 "$(CC_FLAGS_FTRACE)" ]; then \
230 $(sub_cmd_record_mcount) \
231 fi;
232endif # CC_USING_RECORD_MCOUNT
233endif # CONFIG_FTRACE_MCOUNT_RECORD
234
235ifdef CONFIG_STACK_VALIDATION
236ifneq ($(SKIP_STACK_VALIDATION),1)
237
238__objtool_obj := $(objtree)/tools/objtool/objtool
239
240objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
241
242objtool_args += $(if $(part-of-module), --module,)
243
244ifndef CONFIG_FRAME_POINTER
245objtool_args += --no-fp
246endif
247ifdef CONFIG_GCOV_KERNEL
248objtool_args += --no-unreachable
249endif
250ifdef CONFIG_RETPOLINE
251ifneq ($(RETPOLINE_CFLAGS),)
252 objtool_args += --retpoline
253endif
254endif
255
256
257ifdef CONFIG_MODVERSIONS
258objtool_o = $(@D)/.tmp_$(@F)
259else
260objtool_o = $(@)
261endif
262
263# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
264# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
265# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
266cmd_objtool = $(if $(patsubst y%,, \
267 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
268 $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
269objtool_obj = $(if $(patsubst y%,, \
270 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
271 $(__objtool_obj))
272
273endif # SKIP_STACK_VALIDATION
274endif # CONFIG_STACK_VALIDATION
275
276# Rebuild all objects when objtool changes, or is enabled/disabled.
277objtool_dep = $(objtool_obj) \
278 $(wildcard include/config/orc/unwinder.h \
279 include/config/stack/validation.h)
280
281define rule_cc_o_c
282 $(call echo-cmd,checksrc) $(cmd_checksrc) \
283 $(call cmd_and_fixdep,cc_o_c) \
284 $(cmd_checkdoc) \
285 $(call echo-cmd,objtool) $(cmd_objtool) \
286 $(cmd_modversions_c) \
287 $(call echo-cmd,record_mcount) $(cmd_record_mcount)
288endef
289
290define rule_as_o_S
291 $(call cmd_and_fixdep,as_o_S) \
292 $(call echo-cmd,objtool) $(cmd_objtool) \
293 $(cmd_modversions_S)
294endef
295
296# List module undefined symbols (or empty line if not enabled)
297ifdef CONFIG_TRIM_UNUSED_KSYMS
298cmd_undef_syms = $(NM) $@ | sed -n 's/^ *U //p' | xargs echo
299else
300cmd_undef_syms = echo
301endif
302
303# Built-in and composite module parts
304$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
305 $(call cmd,force_checksrc)
306 $(call if_changed_rule,cc_o_c)
307
308# Single-part modules are special since we need to mark them in $(MODVERDIR)
309
310$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
311 $(call cmd,force_checksrc)
312 $(call if_changed_rule,cc_o_c)
313 @{ echo $(@:.o=.ko); echo $@; \
314 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
315
316quiet_cmd_cc_lst_c = MKLST $@
317 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
318 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
319 System.map $(OBJDUMP) > $@
320
321$(obj)/%.lst: $(src)/%.c FORCE
322 $(call if_changed_dep,cc_lst_c)
323
324# Compile assembler sources (.S)
325# ---------------------------------------------------------------------------
326
327modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
328
329$(real-obj-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
330$(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
331
332# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
333# or a file that it includes, in order to get versioned symbols. We build a
334# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
335# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
336#
337# This is convoluted. The .S file must first be preprocessed to run guards and
338# expand names, then the resulting exports must be constructed into plain
339# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
340# to make the genksyms input.
341#
342# These mirror gensymtypes_c and co above, keep them in synch.
343cmd_gensymtypes_S = \
344 (echo "\#include <linux/kernel.h>" ; \
345 echo "\#include <asm/asm-prototypes.h>" ; \
346 $(CPP) $(a_flags) $< | \
347 grep "\<___EXPORT_SYMBOL\>" | \
348 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
349 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
350 $(GENKSYMS) $(if $(1), -T $(2)) \
351 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
352 $(if $(KBUILD_PRESERVE),-p) \
353 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
354
355quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
356cmd_cc_symtypes_S = \
357 set -e; \
358 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
359 test -s $@ || rm -f $@
360
361$(obj)/%.symtypes : $(src)/%.S FORCE
362 $(call cmd,cc_symtypes_S)
363
364
365quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
366cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
367
368$(obj)/%.s: $(src)/%.S FORCE
369 $(call if_changed_dep,cpp_s_S)
370
371quiet_cmd_as_o_S = AS $(quiet_modtag) $@
372
373ifndef CONFIG_MODVERSIONS
374cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
375
376else
377
378ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
379
380ifeq ($(ASM_PROTOTYPES),)
381cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
382
383else
384
385# versioning matches the C process described above, with difference that
386# we parse asm-prototypes.h C header to get function definitions.
387
388cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
389
390cmd_modversions_S = \
391 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
392 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
393 > $(@D)/.tmp_$(@F:.o=.ver); \
394 \
395 $(LD) $(KBUILD_LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
396 -T $(@D)/.tmp_$(@F:.o=.ver); \
397 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
398 else \
399 mv -f $(@D)/.tmp_$(@F) $@; \
400 fi;
401endif
402endif
403
404$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
405 $(call if_changed_rule,as_o_S)
406
407targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
408targets += $(extra-y) $(MAKECMDGOALS) $(always)
409
410# Linker scripts preprocessor (.lds.S -> .lds)
411# ---------------------------------------------------------------------------
412quiet_cmd_cpp_lds_S = LDS $@
413 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
414 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
415
416$(obj)/%.lds: $(src)/%.lds.S FORCE
417 $(call if_changed_dep,cpp_lds_S)
418
419# ASN.1 grammar
420# ---------------------------------------------------------------------------
421quiet_cmd_asn1_compiler = ASN.1 $@
422 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
423 $(subst .h,.c,$@) $(subst .c,.h,$@)
424
425$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
426 $(call cmd,asn1_compiler)
427
428# Build the compiled-in targets
429# ---------------------------------------------------------------------------
430
431# To build objects in subdirs, we need to descend into the directories
432$(sort $(subdir-obj-y)): $(subdir-ym) ;
433
434#
435# Rule to compile a set of .o files into one .o file
436#
437ifdef builtin-target
438
439# built-in.a archives are made with no symbol table or index which
440# makes them small and fast, but unable to be used by the linker.
441# scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol
442# table and index.
443quiet_cmd_ar_builtin = AR $@
444 cmd_ar_builtin = rm -f $@; \
445 $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^)
446
447$(builtin-target): $(real-obj-y) FORCE
448 $(call if_changed,ar_builtin)
449
450targets += $(builtin-target)
451endif # builtin-target
452
453#
454# Rule to create modules.order file
455#
456# Create commands to either record .ko file or cat modules.order from
457# a subdirectory
458modorder-cmds = \
459 $(foreach m, $(modorder), \
460 $(if $(filter %/modules.order, $m), \
461 cat $m;, echo kernel/$m;))
462
463$(modorder-target): $(subdir-ym) FORCE
464 $(Q)(cat /dev/null; $(modorder-cmds)) > $@
465
466#
467# Rule to compile a set of .o files into one .a file
468#
469ifdef lib-target
470quiet_cmd_link_l_target = AR $@
471
472# lib target archives do get a symbol table and index
473cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
474
475$(lib-target): $(lib-y) FORCE
476 $(call if_changed,link_l_target)
477
478targets += $(lib-target)
479
480dummy-object = $(obj)/.lib_exports.o
481ksyms-lds = $(dot-target).lds
482
483quiet_cmd_export_list = EXPORTS $@
484cmd_export_list = $(OBJDUMP) -h $< | \
485 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
486 rm -f $(dummy-object);\
487 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
488 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
489 rm $(dummy-object) $(ksyms-lds)
490
491$(obj)/lib-ksyms.o: $(lib-target) FORCE
492 $(call if_changed,export_list)
493
494targets += $(obj)/lib-ksyms.o
495
496endif
497
498#
499# Rule to link composite objects
500#
501# Composite objects are specified in kbuild makefile as follows:
502# <composite-object>-objs := <list of .o files>
503# or
504# <composite-object>-y := <list of .o files>
505# or
506# <composite-object>-m := <list of .o files>
507# The -m syntax only works if <composite object> is a module
508link_multi_deps = \
509$(filter $(addprefix $(obj)/, \
510$($(subst $(obj)/,,$(@:.o=-objs))) \
511$($(subst $(obj)/,,$(@:.o=-y))) \
512$($(subst $(obj)/,,$(@:.o=-m)))), $^)
513
514quiet_cmd_link_multi-m = LD [M] $@
515cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
516
517$(multi-used-m): FORCE
518 $(call if_changed,link_multi-m)
519 @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
520 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
521$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
522
523targets += $(multi-used-m)
524targets := $(filter-out $(PHONY), $(targets))
525
526# Add intermediate targets:
527# When building objects with specific suffix patterns, add intermediate
528# targets that the final targets are derived from.
529intermediate_targets = $(foreach sfx, $(2), \
530 $(patsubst %$(strip $(1)),%$(sfx), \
531 $(filter %$(strip $(1)), $(targets))))
532# %.asn1.o <- %.asn1.[ch] <- %.asn1
533# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
534# %.lex.o <- %.lex.c <- %.l
535# %.tab.o <- %.tab.[ch] <- %.y
536targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
537 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
538 $(call intermediate_targets, .lex.o, .lex.c) \
539 $(call intermediate_targets, .tab.o, .tab.c .tab.h)
540
541# Descending
542# ---------------------------------------------------------------------------
543
544PHONY += $(subdir-ym)
545$(subdir-ym):
546 $(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1)
547
548# Add FORCE to the prequisites of a target to force it to be always rebuilt.
549# ---------------------------------------------------------------------------
550
551PHONY += FORCE
552
553FORCE:
554
555# Read all saved command lines and dependencies for the $(targets) we
556# may be building above, using $(if_changed{,_dep}). As an
557# optimization, we don't need to read them if the target does not
558# exist, we will rebuild anyway in that case.
559
560cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
561
562ifneq ($(cmd_files),)
563 include $(cmd_files)
564endif
565
566ifneq ($(KBUILD_SRC),)
567# Create directories for object files if they do not exist
568obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
569# If cmd_files exist, their directories apparently exist. Skip mkdir.
570exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files))))
571obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs)))
572ifneq ($(obj-dirs),)
573$(shell mkdir -p $(obj-dirs))
574endif
575endif
576
577# Some files contained in $(targets) are intermediate artifacts.
578# We never want them to be removed automatically.
579.SECONDARY: $(targets)
580
581.PHONY: $(PHONY)