1 # SPDX-License-Identifier: GPL-2.0
2 # ==========================================================================
4 # ==========================================================================
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
34 # Read auto.conf if it exists, otherwise ignore
35 -include include/config/auto.conf
37 include scripts/Kbuild.include
39 # For backward compatibility check that these variables do not change
40 save-cflags := $(CFLAGS)
42 # The filename Kbuild has precedence over Makefile
43 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
44 kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
45 include $(kbuild-file)
47 # If the save-* variables changed error out
48 ifeq ($(KBUILD_NOPEDANTIC),)
49 ifneq ("$(save-cflags)","$(CFLAGS)")
50 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
54 include scripts/Makefile.lib
57 ifneq ($(hostprogs-y),$(host-progs))
58 $(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
59 hostprogs-y += $(host-progs)
63 # Do not include host rules unless needed
64 ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
65 include scripts/Makefile.host
68 ifneq ($(KBUILD_SRC),)
69 # Create output directory if not already present
70 _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
72 # Create directories for object files if directory does not exist
73 # Needed when obj-y := dir/file.o syntax is used
74 _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
78 $(warning kbuild: Makefile.build is included improperly)
81 # ===========================================================================
83 ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
84 lib-target := $(obj)/lib.a
85 obj-y += $(obj)/lib-ksyms.o
88 ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
89 builtin-target := $(obj)/built-in.o
92 modorder-target := $(obj)/modules.order
94 # We keep a list of all modules in $(MODVERDIR)
96 __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
97 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
98 $(subdir-ym) $(always)
101 # Linus' kernel sanity checking tool
102 ifneq ($(KBUILD_CHECKSRC),0)
103 ifeq ($(KBUILD_CHECKSRC),2)
104 quiet_cmd_force_checksrc = CHECK $<
105 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
107 quiet_cmd_checksrc = CHECK $<
108 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
112 # Do section mismatch analysis for each module/built-in.o
113 ifdef CONFIG_DEBUG_SECTION_MISMATCH
114 cmd_secanalysis = ; scripts/mod/modpost $@
117 # Compile C sources (.c)
118 # ---------------------------------------------------------------------------
120 # Default is built-in, unless we know otherwise
122 $(if $(part-of-module), \
123 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
124 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
125 quiet_modtag := $(empty) $(empty)
127 $(real-objs-m) : part-of-module := y
128 $(real-objs-m:.o=.i) : part-of-module := y
129 $(real-objs-m:.o=.s) : part-of-module := y
130 $(real-objs-m:.o=.lst): part-of-module := y
132 $(real-objs-m) : quiet_modtag := [M]
133 $(real-objs-m:.o=.i) : quiet_modtag := [M]
134 $(real-objs-m:.o=.s) : quiet_modtag := [M]
135 $(real-objs-m:.o=.lst): quiet_modtag := [M]
137 $(obj-m) : quiet_modtag := [M]
139 # Default for not multi-part modules
140 modname = $(basetarget)
142 $(multi-objs-m) : modname = $(modname-multi)
143 $(multi-objs-m:.o=.i) : modname = $(modname-multi)
144 $(multi-objs-m:.o=.s) : modname = $(modname-multi)
145 $(multi-objs-m:.o=.lst) : modname = $(modname-multi)
146 $(multi-objs-y) : modname = $(modname-multi)
147 $(multi-objs-y:.o=.i) : modname = $(modname-multi)
148 $(multi-objs-y:.o=.s) : modname = $(modname-multi)
149 $(multi-objs-y:.o=.lst) : modname = $(modname-multi)
151 quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
152 cmd_cc_s_c = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
154 $(obj)/%.s: $(src)/%.c FORCE
155 $(call if_changed_dep,cc_s_c)
157 quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
158 cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
160 $(obj)/%.i: $(src)/%.c FORCE
161 $(call if_changed_dep,cpp_i_c)
163 # These mirror gensymtypes_S and co below, keep them in synch.
164 cmd_gensymtypes_c = \
165 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
166 $(GENKSYMS) $(if $(1), -T $(2)) \
167 $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
168 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
169 $(if $(KBUILD_PRESERVE),-p) \
170 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
172 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
173 cmd_cc_symtypes_c = \
175 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \
176 test -s $@ || rm -f $@
178 $(obj)/%.symtypes : $(src)/%.c FORCE
179 $(call cmd,cc_symtypes_c)
182 # Generate .ll files from .c
183 quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
184 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
186 $(obj)/%.ll: $(src)/%.c FORCE
187 $(call if_changed_dep,cc_ll_c)
190 # The C file is compiled and updated dependency information is generated.
191 # (See cmd_cc_o_c + relevant part of rule_cc_o_c)
193 quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
195 ifndef CONFIG_MODVERSIONS
196 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
199 # When module versioning is enabled the following steps are executed:
200 # o compile a .tmp_<file>.o from <file>.c
201 # o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
202 # not export symbols, we just rename .tmp_<file>.o to <file>.o and
204 # o otherwise, we calculate symbol versions using the good old
205 # genksyms on the preprocessed source and postprocess them in a way
206 # that they are usable as a linker script
207 # o generate <file>.o from .tmp_<file>.o using the linker to
208 # replace the unresolved symbols __crc_exported_symbol with
209 # the actual value of the checksum generated by genksyms
211 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
213 cmd_modversions_c = \
214 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
215 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
216 > $(@D)/.tmp_$(@F:.o=.ver); \
218 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
219 -T $(@D)/.tmp_$(@F:.o=.ver); \
220 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
222 mv -f $(@D)/.tmp_$(@F) $@; \
226 ifdef CONFIG_FTRACE_MCOUNT_RECORD
227 ifndef CC_USING_RECORD_MCOUNT
228 # compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
229 ifdef BUILD_C_RECORDMCOUNT
230 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
231 RECORDMCOUNT_FLAGS = -w
233 # Due to recursion, we must skip empty.o.
234 # The empty.o file is created in the make process in order to determine
235 # the target endianness and word size. It is made before all other C
236 # files, including recordmcount.
237 sub_cmd_record_mcount = \
238 if [ $(@) != "scripts/mod/empty.o" ]; then \
239 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
241 recordmcount_source := $(srctree)/scripts/recordmcount.c \
242 $(srctree)/scripts/recordmcount.h
244 sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
245 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
246 "$(if $(CONFIG_64BIT),64,32)" \
247 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
248 "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
249 "$(if $(part-of-module),1,0)" "$(@)";
250 recordmcount_source := $(srctree)/scripts/recordmcount.pl
251 endif # BUILD_C_RECORDMCOUNT
252 cmd_record_mcount = \
253 if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" = \
254 "$(CC_FLAGS_FTRACE)" ]; then \
255 $(sub_cmd_record_mcount) \
257 endif # CC_USING_RECORD_MCOUNT
258 endif # CONFIG_FTRACE_MCOUNT_RECORD
260 ifdef CONFIG_STACK_VALIDATION
261 ifneq ($(SKIP_STACK_VALIDATION),1)
263 __objtool_obj := $(objtree)/tools/objtool/objtool
265 objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
267 objtool_args += $(if $(part-of-module), --module,)
269 ifndef CONFIG_FRAME_POINTER
270 objtool_args += --no-fp
272 ifdef CONFIG_GCOV_KERNEL
273 objtool_args += --no-unreachable
275 objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
277 ifdef CONFIG_RETPOLINE
278 objtool_args += --retpoline
282 ifdef CONFIG_MODVERSIONS
283 objtool_o = $(@D)/.tmp_$(@F)
288 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
289 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
290 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
291 cmd_objtool = $(if $(patsubst y%,, \
292 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
293 $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
294 objtool_obj = $(if $(patsubst y%,, \
295 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
298 endif # SKIP_STACK_VALIDATION
299 endif # CONFIG_STACK_VALIDATION
301 # Rebuild all objects when objtool changes, or is enabled/disabled.
302 objtool_dep = $(objtool_obj) \
303 $(wildcard include/config/orc/unwinder.h \
304 include/config/stack/validation.h)
307 $(call echo-cmd,checksrc) $(cmd_checksrc) \
308 $(call cmd_and_fixdep,cc_o_c) \
309 $(call echo-cmd,objtool) $(cmd_objtool) \
310 $(cmd_modversions_c) \
311 $(call echo-cmd,record_mcount) $(cmd_record_mcount)
315 $(call cmd_and_fixdep,as_o_S) \
316 $(call echo-cmd,objtool) $(cmd_objtool) \
320 # List module undefined symbols (or empty line if not enabled)
321 ifdef CONFIG_TRIM_UNUSED_KSYMS
322 cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
324 cmd_undef_syms = echo
327 # Built-in and composite module parts
328 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
329 $(call cmd,force_checksrc)
330 $(call if_changed_rule,cc_o_c)
332 # Single-part modules are special since we need to mark them in $(MODVERDIR)
334 $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
335 $(call cmd,force_checksrc)
336 $(call if_changed_rule,cc_o_c)
337 @{ echo $(@:.o=.ko); echo $@; \
338 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
340 quiet_cmd_cc_lst_c = MKLST $@
341 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
342 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
343 System.map $(OBJDUMP) > $@
345 $(obj)/%.lst: $(src)/%.c FORCE
346 $(call if_changed_dep,cc_lst_c)
348 # Compile assembler sources (.S)
349 # ---------------------------------------------------------------------------
351 modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
353 $(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
354 $(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
356 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
357 # or a file that it includes, in order to get versioned symbols. We build a
358 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
359 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
361 # This is convoluted. The .S file must first be preprocessed to run guards and
362 # expand names, then the resulting exports must be constructed into plain
363 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
364 # to make the genksyms input.
366 # These mirror gensymtypes_c and co above, keep them in synch.
367 cmd_gensymtypes_S = \
368 (echo "\#include <linux/kernel.h>" ; \
369 echo "\#include <asm/asm-prototypes.h>" ; \
370 $(CPP) $(a_flags) $< | \
371 grep "\<___EXPORT_SYMBOL\>" | \
372 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
373 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
374 $(GENKSYMS) $(if $(1), -T $(2)) \
375 $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
376 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
377 $(if $(KBUILD_PRESERVE),-p) \
378 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
380 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
381 cmd_cc_symtypes_S = \
383 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
384 test -s $@ || rm -f $@
386 $(obj)/%.symtypes : $(src)/%.S FORCE
387 $(call cmd,cc_symtypes_S)
390 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
391 cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
393 $(obj)/%.s: $(src)/%.S FORCE
394 $(call if_changed_dep,cpp_s_S)
396 quiet_cmd_as_o_S = AS $(quiet_modtag) $@
398 ifndef CONFIG_MODVERSIONS
399 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
403 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
405 ifeq ($(ASM_PROTOTYPES),)
406 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
410 # versioning matches the C process described above, with difference that
411 # we parse asm-prototypes.h C header to get function definitions.
413 cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
415 cmd_modversions_S = \
416 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
417 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
418 > $(@D)/.tmp_$(@F:.o=.ver); \
420 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
421 -T $(@D)/.tmp_$(@F:.o=.ver); \
422 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
424 mv -f $(@D)/.tmp_$(@F) $@; \
429 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
430 $(call if_changed_rule,as_o_S)
432 targets += $(real-objs-y) $(real-objs-m) $(lib-y)
433 targets += $(extra-y) $(MAKECMDGOALS) $(always)
435 # Linker scripts preprocessor (.lds.S -> .lds)
436 # ---------------------------------------------------------------------------
437 quiet_cmd_cpp_lds_S = LDS $@
438 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
439 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
441 $(obj)/%.lds: $(src)/%.lds.S FORCE
442 $(call if_changed_dep,cpp_lds_S)
445 # ---------------------------------------------------------------------------
446 quiet_cmd_asn1_compiler = ASN.1 $@
447 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
448 $(subst .h,.c,$@) $(subst .c,.h,$@)
450 .PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
452 $(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
453 $(call cmd,asn1_compiler)
455 # Build the compiled-in targets
456 # ---------------------------------------------------------------------------
458 # To build objects in subdirs, we need to descend into the directories
459 $(sort $(subdir-obj-y)): $(subdir-ym) ;
462 # Rule to compile a set of .o files into one .o file
466 ifdef CONFIG_THIN_ARCHIVES
467 cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
468 cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
469 quiet_cmd_link_o_target = AR $@
471 cmd_make_builtin = $(LD) $(ld_flags) -r -o
472 cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
473 quiet_cmd_link_o_target = LD $@
476 # If the list of objects to link is empty, just create an empty built-in.o
477 cmd_link_o_target = $(if $(strip $(obj-y)),\
478 $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
480 $(cmd_make_empty_builtin) $@)
482 $(builtin-target): $(obj-y) FORCE
483 $(call if_changed,link_o_target)
485 targets += $(builtin-target)
486 endif # builtin-target
489 # Rule to create modules.order file
491 # Create commands to either record .ko file or cat modules.order from
494 $(foreach m, $(modorder), \
495 $(if $(filter %/modules.order, $m), \
496 cat $m;, echo kernel/$m;))
498 $(modorder-target): $(subdir-ym) FORCE
499 $(Q)(cat /dev/null; $(modorder-cmds)) > $@
502 # Rule to compile a set of .o files into one .a file
505 quiet_cmd_link_l_target = AR $@
507 ifdef CONFIG_THIN_ARCHIVES
508 cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
510 cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
513 $(lib-target): $(lib-y) FORCE
514 $(call if_changed,link_l_target)
516 targets += $(lib-target)
518 dummy-object = $(obj)/.lib_exports.o
519 ksyms-lds = $(dot-target).lds
520 ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
521 ref_prefix = EXTERN(_
526 quiet_cmd_export_list = EXPORTS $@
527 cmd_export_list = $(OBJDUMP) -h $< | \
528 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
529 rm -f $(dummy-object);\
530 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
531 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
532 rm $(dummy-object) $(ksyms-lds)
534 $(obj)/lib-ksyms.o: $(lib-target) FORCE
535 $(call if_changed,export_list)
537 targets += $(obj)/lib-ksyms.o
542 # Rule to link composite objects
544 # Composite objects are specified in kbuild makefile as follows:
545 # <composite-object>-objs := <list of .o files>
547 # <composite-object>-y := <list of .o files>
549 # <composite-object>-m := <list of .o files>
550 # The -m syntax only works if <composite object> is a module
552 $(filter $(addprefix $(obj)/, \
553 $($(subst $(obj)/,,$(@:.o=-objs))) \
554 $($(subst $(obj)/,,$(@:.o=-y))) \
555 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
557 cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
559 ifdef CONFIG_THIN_ARCHIVES
560 quiet_cmd_link_multi-y = AR $@
561 cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
563 quiet_cmd_link_multi-y = LD $@
564 cmd_link_multi-y = $(cmd_link_multi-link)
567 quiet_cmd_link_multi-m = LD [M] $@
568 cmd_link_multi-m = $(cmd_link_multi-link)
570 $(multi-used-y): FORCE
571 $(call if_changed,link_multi-y)
572 $(call multi_depend, $(multi-used-y), .o, -objs -y)
574 $(multi-used-m): FORCE
575 $(call if_changed,link_multi-m)
576 @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
577 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
578 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
580 targets += $(multi-used-y) $(multi-used-m)
584 # ---------------------------------------------------------------------------
586 PHONY += $(subdir-ym)
588 $(Q)$(MAKE) $(build)=$@
590 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
591 # ---------------------------------------------------------------------------
597 # Read all saved command lines and dependencies for the $(targets) we
598 # may be building above, using $(if_changed{,_dep}). As an
599 # optimization, we don't need to read them if the target does not
600 # exist, we will rebuild anyway in that case.
602 targets := $(wildcard $(sort $(targets)))
603 cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
605 ifneq ($(cmd_files),)
609 # Declare the contents of the .PHONY variable as phony. We keep that
610 # information in a variable se we can use it in if_changed and friends.