xref: /openbmc/linux/scripts/Makefile.build (revision 1c2dd16a) 
1# ==========================================================================
2# Building
3# ==========================================================================
4
5src := $(obj)
6
7PHONY := __build
8__build:
9
10# Init all relevant variables used in kbuild files so
11# 1) they have correct type
12# 2) they do not inherit any value from the environment
13obj-y :=
14obj-m :=
15lib-y :=
16lib-m :=
17always :=
18targets :=
19subdir-y :=
20subdir-m :=
21EXTRA_AFLAGS   :=
22EXTRA_CFLAGS   :=
23EXTRA_CPPFLAGS :=
24EXTRA_LDFLAGS  :=
25asflags-y  :=
26ccflags-y  :=
27cppflags-y :=
28ldflags-y  :=
29
30subdir-asflags-y :=
31subdir-ccflags-y :=
32
33# Read auto.conf if it exists, otherwise ignore
34-include include/config/auto.conf
35
36include scripts/Kbuild.include
37
38# For backward compatibility check that these variables do not change
39save-cflags := $(CFLAGS)
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 $(kbuild-file)
45
46# If the save-* variables changed error out
47ifeq ($(KBUILD_NOPEDANTIC),)
48        ifneq ("$(save-cflags)","$(CFLAGS)")
49                $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
50        endif
51endif
52
53include scripts/Makefile.lib
54
55ifdef host-progs
56ifneq ($(hostprogs-y),$(host-progs))
57$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
58hostprogs-y += $(host-progs)
59endif
60endif
61
62# Do not include host rules unless needed
63ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
64include scripts/Makefile.host
65endif
66
67ifneq ($(KBUILD_SRC),)
68# Create output directory if not already present
69_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
70
71# Create directories for object files if directory does not exist
72# Needed when obj-y := dir/file.o syntax is used
73_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
74endif
75
76ifndef obj
77$(warning kbuild: Makefile.build is included improperly)
78endif
79
80# ===========================================================================
81
82ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
83lib-target := $(obj)/lib.a
84obj-y += $(obj)/lib-ksyms.o
85endif
86
87ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
88builtin-target := $(obj)/built-in.o
89endif
90
91modorder-target := $(obj)/modules.order
92
93# We keep a list of all modules in $(MODVERDIR)
94
95__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
96	 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
97	 $(subdir-ym) $(always)
98	@:
99
100# Linus' kernel sanity checking tool
101ifneq ($(KBUILD_CHECKSRC),0)
102  ifeq ($(KBUILD_CHECKSRC),2)
103    quiet_cmd_force_checksrc = CHECK   $<
104          cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
105  else
106      quiet_cmd_checksrc     = CHECK   $<
107            cmd_checksrc     = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
108  endif
109endif
110
111# Do section mismatch analysis for each module/built-in.o
112ifdef CONFIG_DEBUG_SECTION_MISMATCH
113  cmd_secanalysis = ; scripts/mod/modpost $@
114endif
115
116# Compile C sources (.c)
117# ---------------------------------------------------------------------------
118
119# Default is built-in, unless we know otherwise
120modkern_cflags =                                          \
121	$(if $(part-of-module),                           \
122		$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
123		$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
124quiet_modtag := $(empty)   $(empty)
125
126$(real-objs-m)        : part-of-module := y
127$(real-objs-m:.o=.i)  : part-of-module := y
128$(real-objs-m:.o=.s)  : part-of-module := y
129$(real-objs-m:.o=.lst): part-of-module := y
130
131$(real-objs-m)        : quiet_modtag := [M]
132$(real-objs-m:.o=.i)  : quiet_modtag := [M]
133$(real-objs-m:.o=.s)  : quiet_modtag := [M]
134$(real-objs-m:.o=.lst): quiet_modtag := [M]
135
136$(obj-m)              : quiet_modtag := [M]
137
138# Default for not multi-part modules
139modname = $(basetarget)
140
141$(multi-objs-m)         : modname = $(modname-multi)
142$(multi-objs-m:.o=.i)   : modname = $(modname-multi)
143$(multi-objs-m:.o=.s)   : modname = $(modname-multi)
144$(multi-objs-m:.o=.lst) : modname = $(modname-multi)
145$(multi-objs-y)         : modname = $(modname-multi)
146$(multi-objs-y:.o=.i)   : modname = $(modname-multi)
147$(multi-objs-y:.o=.s)   : modname = $(modname-multi)
148$(multi-objs-y:.o=.lst) : modname = $(modname-multi)
149
150quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
151cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
152
153$(obj)/%.s: $(src)/%.c FORCE
154	$(call if_changed_dep,cc_s_c)
155
156quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
157cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
158
159$(obj)/%.i: $(src)/%.c FORCE
160	$(call if_changed_dep,cpp_i_c)
161
162# These mirror gensymtypes_S and co below, keep them in synch.
163cmd_gensymtypes_c =                                                         \
164    $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
165    $(GENKSYMS) $(if $(1), -T $(2))                                         \
166     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
167     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
168     $(if $(KBUILD_PRESERVE),-p)                                            \
169     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
170
171quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
172cmd_cc_symtypes_c =                                                         \
173    set -e;                                                                 \
174    $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
175    test -s $@ || rm -f $@
176
177$(obj)/%.symtypes : $(src)/%.c FORCE
178	$(call cmd,cc_symtypes_c)
179
180# C (.c) files
181# The C file is compiled and updated dependency information is generated.
182# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
183
184quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
185
186ifndef CONFIG_MODVERSIONS
187cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
188
189else
190# When module versioning is enabled the following steps are executed:
191# o compile a .tmp_<file>.o from <file>.c
192# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
193#   not export symbols, we just rename .tmp_<file>.o to <file>.o and
194#   are done.
195# o otherwise, we calculate symbol versions using the good old
196#   genksyms on the preprocessed source and postprocess them in a way
197#   that they are usable as a linker script
198# o generate <file>.o from .tmp_<file>.o using the linker to
199#   replace the unresolved symbols __crc_exported_symbol with
200#   the actual value of the checksum generated by genksyms
201
202cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
203
204cmd_modversions_c =								\
205	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
206		$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
207		    > $(@D)/.tmp_$(@F:.o=.ver);					\
208										\
209		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 			\
210			-T $(@D)/.tmp_$(@F:.o=.ver);				\
211		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);		\
212	else									\
213		mv -f $(@D)/.tmp_$(@F) $@;					\
214	fi;
215endif
216
217ifdef CONFIG_FTRACE_MCOUNT_RECORD
218ifdef BUILD_C_RECORDMCOUNT
219ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
220  RECORDMCOUNT_FLAGS = -w
221endif
222# Due to recursion, we must skip empty.o.
223# The empty.o file is created in the make process in order to determine
224#  the target endianness and word size. It is made before all other C
225#  files, including recordmcount.
226sub_cmd_record_mcount =					\
227	if [ $(@) != "scripts/mod/empty.o" ]; then	\
228		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\
229	fi;
230recordmcount_source := $(srctree)/scripts/recordmcount.c \
231		    $(srctree)/scripts/recordmcount.h
232else
233sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
234	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
235	"$(if $(CONFIG_64BIT),64,32)" \
236	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
237	"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
238	"$(if $(part-of-module),1,0)" "$(@)";
239recordmcount_source := $(srctree)/scripts/recordmcount.pl
240endif
241cmd_record_mcount =						\
242	if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =	\
243	     "$(CC_FLAGS_FTRACE)" ]; then			\
244		$(sub_cmd_record_mcount)			\
245	fi;
246endif
247
248ifdef CONFIG_STACK_VALIDATION
249ifneq ($(SKIP_STACK_VALIDATION),1)
250
251__objtool_obj := $(objtree)/tools/objtool/objtool
252
253objtool_args = check
254ifndef CONFIG_FRAME_POINTER
255objtool_args += --no-fp
256endif
257
258# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
259# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
260# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
261cmd_objtool = $(if $(patsubst y%,, \
262	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
263	$(__objtool_obj) $(objtool_args) "$(@)";)
264objtool_obj = $(if $(patsubst y%,, \
265	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
266	$(__objtool_obj))
267
268endif # SKIP_STACK_VALIDATION
269endif # CONFIG_STACK_VALIDATION
270
271define rule_cc_o_c
272	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
273	$(call cmd_and_fixdep,cc_o_c)					  \
274	$(cmd_modversions_c)						  \
275	$(cmd_objtool)						          \
276	$(call echo-cmd,record_mcount) $(cmd_record_mcount)
277endef
278
279define rule_as_o_S
280	$(call cmd_and_fixdep,as_o_S)					  \
281	$(cmd_modversions_S)						  \
282	$(cmd_objtool)
283endef
284
285# List module undefined symbols (or empty line if not enabled)
286ifdef CONFIG_TRIM_UNUSED_KSYMS
287cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
288else
289cmd_undef_syms = echo
290endif
291
292# Built-in and composite module parts
293$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE
294	$(call cmd,force_checksrc)
295	$(call if_changed_rule,cc_o_c)
296
297# Single-part modules are special since we need to mark them in $(MODVERDIR)
298
299$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE
300	$(call cmd,force_checksrc)
301	$(call if_changed_rule,cc_o_c)
302	@{ echo $(@:.o=.ko); echo $@; \
303	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
304
305quiet_cmd_cc_lst_c = MKLST   $@
306      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
307		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
308				     System.map $(OBJDUMP) > $@
309
310$(obj)/%.lst: $(src)/%.c FORCE
311	$(call if_changed_dep,cc_lst_c)
312
313# Compile assembler sources (.S)
314# ---------------------------------------------------------------------------
315
316modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
317
318$(real-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
319$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
320
321# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
322# or a file that it includes, in order to get versioned symbols. We build a
323# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
324# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
325#
326# This is convoluted. The .S file must first be preprocessed to run guards and
327# expand names, then the resulting exports must be constructed into plain
328# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
329# to make the genksyms input.
330#
331# These mirror gensymtypes_c and co above, keep them in synch.
332cmd_gensymtypes_S =                                                         \
333    (echo "\#include <linux/kernel.h>" ;                                    \
334     echo "\#include <asm/asm-prototypes.h>" ;                              \
335    $(CPP) $(a_flags) $< |                                                  \
336     grep "\<___EXPORT_SYMBOL\>" |                                          \
337     sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
338    $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
339    $(GENKSYMS) $(if $(1), -T $(2))                                         \
340     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
341     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
342     $(if $(KBUILD_PRESERVE),-p)                                            \
343     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
344
345quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
346cmd_cc_symtypes_S =                                                         \
347    set -e;                                                                 \
348    $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
349    test -s $@ || rm -f $@
350
351$(obj)/%.symtypes : $(src)/%.S FORCE
352	$(call cmd,cc_symtypes_S)
353
354
355quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
356cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
357
358$(obj)/%.s: $(src)/%.S FORCE
359	$(call if_changed_dep,cpp_s_S)
360
361quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
362
363ifndef CONFIG_MODVERSIONS
364cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
365
366else
367
368ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
369
370ifeq ($(ASM_PROTOTYPES),)
371cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
372
373else
374
375# versioning matches the C process described above, with difference that
376# we parse asm-prototypes.h C header to get function definitions.
377
378cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
379
380cmd_modversions_S =								\
381	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
382		$(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
383		    > $(@D)/.tmp_$(@F:.o=.ver);					\
384										\
385		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 			\
386			-T $(@D)/.tmp_$(@F:.o=.ver);				\
387		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);		\
388	else									\
389		mv -f $(@D)/.tmp_$(@F) $@;					\
390	fi;
391endif
392endif
393
394$(obj)/%.o: $(src)/%.S $(objtool_obj) FORCE
395	$(call if_changed_rule,as_o_S)
396
397targets += $(real-objs-y) $(real-objs-m) $(lib-y)
398targets += $(extra-y) $(MAKECMDGOALS) $(always)
399
400# Linker scripts preprocessor (.lds.S -> .lds)
401# ---------------------------------------------------------------------------
402quiet_cmd_cpp_lds_S = LDS     $@
403      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
404	                     -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
405
406$(obj)/%.lds: $(src)/%.lds.S FORCE
407	$(call if_changed_dep,cpp_lds_S)
408
409# ASN.1 grammar
410# ---------------------------------------------------------------------------
411quiet_cmd_asn1_compiler = ASN.1   $@
412      cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
413				$(subst .h,.c,$@) $(subst .c,.h,$@)
414
415.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
416
417$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
418	$(call cmd,asn1_compiler)
419
420# Build the compiled-in targets
421# ---------------------------------------------------------------------------
422
423# To build objects in subdirs, we need to descend into the directories
424$(sort $(subdir-obj-y)): $(subdir-ym) ;
425
426#
427# Rule to compile a set of .o files into one .o file
428#
429ifdef builtin-target
430
431ifdef CONFIG_THIN_ARCHIVES
432  cmd_make_builtin = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS)
433  cmd_make_empty_builtin = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS)
434  quiet_cmd_link_o_target = AR      $@
435else
436  cmd_make_builtin = $(LD) $(ld_flags) -r -o
437  cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
438  quiet_cmd_link_o_target = LD      $@
439endif
440
441# If the list of objects to link is empty, just create an empty built-in.o
442cmd_link_o_target = $(if $(strip $(obj-y)),\
443		      $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
444		      $(cmd_secanalysis),\
445		      $(cmd_make_empty_builtin) $@)
446
447$(builtin-target): $(obj-y) FORCE
448	$(call if_changed,link_o_target)
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
472ifdef CONFIG_THIN_ARCHIVES
473  cmd_link_l_target = rm -f $@; $(AR) rcsT$(KBUILD_ARFLAGS) $@ $(lib-y)
474else
475  cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
476endif
477
478$(lib-target): $(lib-y) FORCE
479	$(call if_changed,link_l_target)
480
481targets += $(lib-target)
482
483dummy-object = $(obj)/.lib_exports.o
484ksyms-lds = $(dot-target).lds
485ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
486ref_prefix = EXTERN(_
487else
488ref_prefix = EXTERN(
489endif
490
491quiet_cmd_export_list = EXPORTS $@
492cmd_export_list = $(OBJDUMP) -h $< | \
493	sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
494	rm -f $(dummy-object);\
495	echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
496	$(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
497	rm $(dummy-object) $(ksyms-lds)
498
499$(obj)/lib-ksyms.o: $(lib-target) FORCE
500	$(call if_changed,export_list)
501
502targets += $(obj)/lib-ksyms.o
503
504endif
505
506#
507# Rule to link composite objects
508#
509#  Composite objects are specified in kbuild makefile as follows:
510#    <composite-object>-objs := <list of .o files>
511#  or
512#    <composite-object>-y    := <list of .o files>
513#  or
514#    <composite-object>-m    := <list of .o files>
515#  The -m syntax only works if <composite object> is a module
516link_multi_deps =                     \
517$(filter $(addprefix $(obj)/,         \
518$($(subst $(obj)/,,$(@:.o=-objs)))    \
519$($(subst $(obj)/,,$(@:.o=-y)))       \
520$($(subst $(obj)/,,$(@:.o=-m)))), $^)
521
522cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
523
524ifdef CONFIG_THIN_ARCHIVES
525  quiet_cmd_link_multi-y = AR      $@
526  cmd_link_multi-y = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
527else
528  quiet_cmd_link_multi-y = LD      $@
529  cmd_link_multi-y = $(cmd_link_multi-link)
530endif
531
532quiet_cmd_link_multi-m = LD [M]  $@
533cmd_link_multi-m = $(cmd_link_multi-link)
534
535$(multi-used-y): FORCE
536	$(call if_changed,link_multi-y)
537$(call multi_depend, $(multi-used-y), .o, -objs -y)
538
539$(multi-used-m): FORCE
540	$(call if_changed,link_multi-m)
541	@{ echo $(@:.o=.ko); echo $(link_multi_deps); \
542	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
543$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
544
545targets += $(multi-used-y) $(multi-used-m)
546
547
548# Descending
549# ---------------------------------------------------------------------------
550
551PHONY += $(subdir-ym)
552$(subdir-ym):
553	$(Q)$(MAKE) $(build)=$@
554
555# Add FORCE to the prequisites of a target to force it to be always rebuilt.
556# ---------------------------------------------------------------------------
557
558PHONY += FORCE
559
560FORCE:
561
562# Read all saved command lines and dependencies for the $(targets) we
563# may be building above, using $(if_changed{,_dep}). As an
564# optimization, we don't need to read them if the target does not
565# exist, we will rebuild anyway in that case.
566
567targets := $(wildcard $(sort $(targets)))
568cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
569
570ifneq ($(cmd_files),)
571  include $(cmd_files)
572endif
573
574# Declare the contents of the .PHONY variable as phony.  We keep that
575# information in a variable se we can use it in if_changed and friends.
576
577.PHONY: $(PHONY)
578