xref: /openbmc/linux/scripts/Makefile.build (revision fca3aa16) 
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
56ifdef host-progs
57ifneq ($(hostprogs-y),$(host-progs))
58$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
59hostprogs-y += $(host-progs)
60endif
61endif
62
63# Do not include host rules unless needed
64ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
65include scripts/Makefile.host
66endif
67
68ifndef obj
69$(warning kbuild: Makefile.build is included improperly)
70endif
71
72# ===========================================================================
73
74ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
75lib-target := $(obj)/lib.a
76real-obj-y += $(obj)/lib-ksyms.o
77endif
78
79ifneq ($(strip $(real-obj-y) $(need-builtin)),)
80builtin-target := $(obj)/built-in.a
81endif
82
83modorder-target := $(obj)/modules.order
84
85# We keep a list of all modules in $(MODVERDIR)
86
87__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
88	 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
89	 $(subdir-ym) $(always)
90	@:
91
92# Linus' kernel sanity checking tool
93ifneq ($(KBUILD_CHECKSRC),0)
94  ifeq ($(KBUILD_CHECKSRC),2)
95    quiet_cmd_force_checksrc = CHECK   $<
96          cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
97  else
98      quiet_cmd_checksrc     = CHECK   $<
99            cmd_checksrc     = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
100  endif
101endif
102
103ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
104  cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< ;
105endif
106
107# Do section mismatch analysis for each module/built-in.a
108ifdef CONFIG_DEBUG_SECTION_MISMATCH
109  cmd_secanalysis = ; scripts/mod/modpost $@
110endif
111
112# Compile C sources (.c)
113# ---------------------------------------------------------------------------
114
115# Default is built-in, unless we know otherwise
116modkern_cflags =                                          \
117	$(if $(part-of-module),                           \
118		$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
119		$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
120quiet_modtag := $(empty)   $(empty)
121
122$(real-obj-m)        : part-of-module := y
123$(real-obj-m:.o=.i)  : part-of-module := y
124$(real-obj-m:.o=.s)  : part-of-module := y
125$(real-obj-m:.o=.lst): part-of-module := y
126
127$(real-obj-m)        : quiet_modtag := [M]
128$(real-obj-m:.o=.i)  : quiet_modtag := [M]
129$(real-obj-m:.o=.s)  : quiet_modtag := [M]
130$(real-obj-m:.o=.lst): quiet_modtag := [M]
131
132$(obj-m)             : quiet_modtag := [M]
133
134quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
135cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
136
137$(obj)/%.s: $(src)/%.c FORCE
138	$(call if_changed_dep,cc_s_c)
139
140quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
141cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
142
143$(obj)/%.i: $(src)/%.c FORCE
144	$(call if_changed_dep,cpp_i_c)
145
146# These mirror gensymtypes_S and co below, keep them in synch.
147cmd_gensymtypes_c =                                                         \
148    $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
149    $(GENKSYMS) $(if $(1), -T $(2))                                         \
150     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
151     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
152     $(if $(KBUILD_PRESERVE),-p)                                            \
153     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
154
155quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
156cmd_cc_symtypes_c =                                                         \
157    set -e;                                                                 \
158    $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
159    test -s $@ || rm -f $@
160
161$(obj)/%.symtypes : $(src)/%.c FORCE
162	$(call cmd,cc_symtypes_c)
163
164# LLVM assembly
165# Generate .ll files from .c
166quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
167      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
168
169$(obj)/%.ll: $(src)/%.c FORCE
170	$(call if_changed_dep,cc_ll_c)
171
172# C (.c) files
173# The C file is compiled and updated dependency information is generated.
174# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
175
176quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
177
178ifndef CONFIG_MODVERSIONS
179cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
180
181else
182# When module versioning is enabled the following steps are executed:
183# o compile a .tmp_<file>.o from <file>.c
184# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
185#   not export symbols, we just rename .tmp_<file>.o to <file>.o and
186#   are done.
187# o otherwise, we calculate symbol versions using the good old
188#   genksyms on the preprocessed source and postprocess them in a way
189#   that they are usable as a linker script
190# o generate <file>.o from .tmp_<file>.o using the linker to
191#   replace the unresolved symbols __crc_exported_symbol with
192#   the actual value of the checksum generated by genksyms
193
194cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
195
196cmd_modversions_c =								\
197	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
198		$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
199		    > $(@D)/.tmp_$(@F:.o=.ver);					\
200										\
201		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 			\
202			-T $(@D)/.tmp_$(@F:.o=.ver);				\
203		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);		\
204	else									\
205		mv -f $(@D)/.tmp_$(@F) $@;					\
206	fi;
207endif
208
209ifdef CONFIG_FTRACE_MCOUNT_RECORD
210ifdef BUILD_C_RECORDMCOUNT
211ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
212  RECORDMCOUNT_FLAGS = -w
213endif
214# Due to recursion, we must skip empty.o.
215# The empty.o file is created in the make process in order to determine
216# the target endianness and word size. It is made before all other C
217# files, including recordmcount.
218sub_cmd_record_mcount =					\
219	if [ $(@) != "scripts/mod/empty.o" ]; then	\
220		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\
221	fi;
222recordmcount_source := $(srctree)/scripts/recordmcount.c \
223		    $(srctree)/scripts/recordmcount.h
224else
225sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
226	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
227	"$(if $(CONFIG_64BIT),64,32)" \
228	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
229	"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
230	"$(if $(part-of-module),1,0)" "$(@)";
231recordmcount_source := $(srctree)/scripts/recordmcount.pl
232endif # BUILD_C_RECORDMCOUNT
233cmd_record_mcount =						\
234	if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =	\
235	     "$(CC_FLAGS_FTRACE)" ]; then			\
236		$(sub_cmd_record_mcount)			\
237	fi;
238endif # CONFIG_FTRACE_MCOUNT_RECORD
239
240ifdef CONFIG_STACK_VALIDATION
241ifneq ($(SKIP_STACK_VALIDATION),1)
242
243__objtool_obj := $(objtree)/tools/objtool/objtool
244
245objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
246
247objtool_args += $(if $(part-of-module), --module,)
248
249ifndef CONFIG_FRAME_POINTER
250objtool_args += --no-fp
251endif
252ifdef CONFIG_GCOV_KERNEL
253objtool_args += --no-unreachable
254else
255objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
256endif
257ifdef CONFIG_RETPOLINE
258ifneq ($(RETPOLINE_CFLAGS),)
259  objtool_args += --retpoline
260endif
261endif
262
263
264ifdef CONFIG_MODVERSIONS
265objtool_o = $(@D)/.tmp_$(@F)
266else
267objtool_o = $(@)
268endif
269
270# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
271# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
272# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
273cmd_objtool = $(if $(patsubst y%,, \
274	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
275	$(__objtool_obj) $(objtool_args) "$(objtool_o)";)
276objtool_obj = $(if $(patsubst y%,, \
277	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
278	$(__objtool_obj))
279
280endif # SKIP_STACK_VALIDATION
281endif # CONFIG_STACK_VALIDATION
282
283# Rebuild all objects when objtool changes, or is enabled/disabled.
284objtool_dep = $(objtool_obj)					\
285	      $(wildcard include/config/orc/unwinder.h		\
286			 include/config/stack/validation.h)
287
288define rule_cc_o_c
289	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
290	$(call cmd_and_fixdep,cc_o_c)					  \
291	$(cmd_checkdoc)							  \
292	$(call echo-cmd,objtool) $(cmd_objtool)				  \
293	$(cmd_modversions_c)						  \
294	$(call echo-cmd,record_mcount) $(cmd_record_mcount)
295endef
296
297define rule_as_o_S
298	$(call cmd_and_fixdep,as_o_S)					  \
299	$(call echo-cmd,objtool) $(cmd_objtool)				  \
300	$(cmd_modversions_S)
301endef
302
303# List module undefined symbols (or empty line if not enabled)
304ifdef CONFIG_TRIM_UNUSED_KSYMS
305cmd_undef_syms = $(NM) $@ | sed -n 's/^  *U //p' | xargs echo
306else
307cmd_undef_syms = echo
308endif
309
310# Built-in and composite module parts
311$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
312	$(call cmd,force_checksrc)
313	$(call if_changed_rule,cc_o_c)
314
315# Single-part modules are special since we need to mark them in $(MODVERDIR)
316
317$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
318	$(call cmd,force_checksrc)
319	$(call if_changed_rule,cc_o_c)
320	@{ echo $(@:.o=.ko); echo $@; \
321	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
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
334modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
335
336$(real-obj-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
337$(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
338
339# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
340# or a file that it includes, in order to get versioned symbols. We build a
341# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
342# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
343#
344# This is convoluted. The .S file must first be preprocessed to run guards and
345# expand names, then the resulting exports must be constructed into plain
346# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
347# to make the genksyms input.
348#
349# These mirror gensymtypes_c and co above, keep them in synch.
350cmd_gensymtypes_S =                                                         \
351    (echo "\#include <linux/kernel.h>" ;                                    \
352     echo "\#include <asm/asm-prototypes.h>" ;                              \
353    $(CPP) $(a_flags) $< |                                                  \
354     grep "\<___EXPORT_SYMBOL\>" |                                          \
355     sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
356    $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
357    $(GENKSYMS) $(if $(1), -T $(2))                                         \
358     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
359     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
360     $(if $(KBUILD_PRESERVE),-p)                                            \
361     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
362
363quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
364cmd_cc_symtypes_S =                                                         \
365    set -e;                                                                 \
366    $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
367    test -s $@ || rm -f $@
368
369$(obj)/%.symtypes : $(src)/%.S FORCE
370	$(call cmd,cc_symtypes_S)
371
372
373quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
374cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
375
376$(obj)/%.s: $(src)/%.S FORCE
377	$(call if_changed_dep,cpp_s_S)
378
379quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
380
381ifndef CONFIG_MODVERSIONS
382cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
383
384else
385
386ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
387
388ifeq ($(ASM_PROTOTYPES),)
389cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
390
391else
392
393# versioning matches the C process described above, with difference that
394# we parse asm-prototypes.h C header to get function definitions.
395
396cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
397
398cmd_modversions_S =								\
399	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
400		$(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
401		    > $(@D)/.tmp_$(@F:.o=.ver);					\
402										\
403		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 			\
404			-T $(@D)/.tmp_$(@F:.o=.ver);				\
405		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);		\
406	else									\
407		mv -f $(@D)/.tmp_$(@F) $@;					\
408	fi;
409endif
410endif
411
412$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
413	$(call if_changed_rule,as_o_S)
414
415targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
416targets += $(extra-y) $(MAKECMDGOALS) $(always)
417
418# Linker scripts preprocessor (.lds.S -> .lds)
419# ---------------------------------------------------------------------------
420quiet_cmd_cpp_lds_S = LDS     $@
421      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
422	                     -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
423
424$(obj)/%.lds: $(src)/%.lds.S FORCE
425	$(call if_changed_dep,cpp_lds_S)
426
427# ASN.1 grammar
428# ---------------------------------------------------------------------------
429quiet_cmd_asn1_compiler = ASN.1   $@
430      cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
431				$(subst .h,.c,$@) $(subst .c,.h,$@)
432
433$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
434	$(call cmd,asn1_compiler)
435
436# Build the compiled-in targets
437# ---------------------------------------------------------------------------
438
439# To build objects in subdirs, we need to descend into the directories
440$(sort $(subdir-obj-y)): $(subdir-ym) ;
441
442#
443# Rule to compile a set of .o files into one .o file
444#
445ifdef builtin-target
446
447# built-in.a archives are made with no symbol table or index which
448# makes them small and fast, but unable to be used by the linker.
449# scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol
450# table and index.
451quiet_cmd_ar_builtin = AR      $@
452      cmd_ar_builtin = rm -f $@; \
453                     $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^)
454
455$(builtin-target): $(real-obj-y) FORCE
456	$(call if_changed,ar_builtin)
457
458targets += $(builtin-target)
459endif # builtin-target
460
461#
462# Rule to create modules.order file
463#
464# Create commands to either record .ko file or cat modules.order from
465# a subdirectory
466modorder-cmds =						\
467	$(foreach m, $(modorder),			\
468		$(if $(filter %/modules.order, $m),	\
469			cat $m;, echo kernel/$m;))
470
471$(modorder-target): $(subdir-ym) FORCE
472	$(Q)(cat /dev/null; $(modorder-cmds)) > $@
473
474#
475# Rule to compile a set of .o files into one .a file
476#
477ifdef lib-target
478quiet_cmd_link_l_target = AR      $@
479
480# lib target archives do get a symbol table and index
481cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
482
483$(lib-target): $(lib-y) FORCE
484	$(call if_changed,link_l_target)
485
486targets += $(lib-target)
487
488dummy-object = $(obj)/.lib_exports.o
489ksyms-lds = $(dot-target).lds
490ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
491ref_prefix = EXTERN(_
492else
493ref_prefix = EXTERN(
494endif
495
496quiet_cmd_export_list = EXPORTS $@
497cmd_export_list = $(OBJDUMP) -h $< | \
498	sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
499	rm -f $(dummy-object);\
500	echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
501	$(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
502	rm $(dummy-object) $(ksyms-lds)
503
504$(obj)/lib-ksyms.o: $(lib-target) FORCE
505	$(call if_changed,export_list)
506
507targets += $(obj)/lib-ksyms.o
508
509endif
510
511#
512# Rule to link composite objects
513#
514#  Composite objects are specified in kbuild makefile as follows:
515#    <composite-object>-objs := <list of .o files>
516#  or
517#    <composite-object>-y    := <list of .o files>
518#  or
519#    <composite-object>-m    := <list of .o files>
520#  The -m syntax only works if <composite object> is a module
521link_multi_deps =                     \
522$(filter $(addprefix $(obj)/,         \
523$($(subst $(obj)/,,$(@:.o=-objs)))    \
524$($(subst $(obj)/,,$(@:.o=-y)))       \
525$($(subst $(obj)/,,$(@:.o=-m)))), $^)
526
527quiet_cmd_link_multi-m = LD [M]  $@
528cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
529
530$(multi-used-m): FORCE
531	$(call if_changed,link_multi-m)
532	@{ echo $(@:.o=.ko); echo $(link_multi_deps); \
533	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
534$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
535
536targets += $(multi-used-m)
537targets := $(filter-out $(PHONY), $(targets))
538
539# Add intermediate targets:
540# When building objects with specific suffix patterns, add intermediate
541# targets that the final targets are derived from.
542intermediate_targets = $(foreach sfx, $(2), \
543				$(patsubst %$(strip $(1)),%$(sfx), \
544					$(filter %$(strip $(1)), $(targets))))
545# %.asn1.o <- %.asn1.[ch] <- %.asn1
546# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
547# %.lex.o <- %.lex.c <- %.l
548# %.tab.o <- %.tab.[ch] <- %.y
549targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
550	   $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
551	   $(call intermediate_targets, .lex.o, .lex.c) \
552	   $(call intermediate_targets, .tab.o, .tab.c .tab.h)
553
554# Descending
555# ---------------------------------------------------------------------------
556
557PHONY += $(subdir-ym)
558$(subdir-ym):
559	$(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1)
560
561# Add FORCE to the prequisites of a target to force it to be always rebuilt.
562# ---------------------------------------------------------------------------
563
564PHONY += FORCE
565
566FORCE:
567
568# Read all saved command lines and dependencies for the $(targets) we
569# may be building above, using $(if_changed{,_dep}). As an
570# optimization, we don't need to read them if the target does not
571# exist, we will rebuild anyway in that case.
572
573cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
574
575ifneq ($(cmd_files),)
576  include $(cmd_files)
577endif
578
579ifneq ($(KBUILD_SRC),)
580# Create directories for object files if they do not exist
581obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
582# If cmd_files exist, their directories apparently exist.  Skip mkdir.
583exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files))))
584obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs)))
585ifneq ($(obj-dirs),)
586$(shell mkdir -p $(obj-dirs))
587endif
588endif
589
590# Some files contained in $(targets) are intermediate artifacts.
591# We never want them to be removed automatically.
592.SECONDARY: $(targets)
593
594# Declare the contents of the .PHONY variable as phony.  We keep that
595# information in a variable se we can use it in if_changed and friends.
596
597.PHONY: $(PHONY)
598