xref: /linux/scripts/Makefile.build (revision 9a379e77033f02c4a071891afdf0f0a01eff8ccb)
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
76obj-y += $(obj)/lib-ksyms.o
77endif
78
79ifneq ($(strip $(obj-y) $(need-builtin)),)
80builtin-target := $(obj)/built-in.o
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.o
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-objs-m)        : part-of-module := y
123$(real-objs-m:.o=.i)  : part-of-module := y
124$(real-objs-m:.o=.s)  : part-of-module := y
125$(real-objs-m:.o=.lst): part-of-module := y
126
127$(real-objs-m)        : quiet_modtag := [M]
128$(real-objs-m:.o=.i)  : quiet_modtag := [M]
129$(real-objs-m:.o=.s)  : quiet_modtag := [M]
130$(real-objs-m:.o=.lst): quiet_modtag := [M]
131
132$(obj-m)              : quiet_modtag := [M]
133
134# Default for not multi-part modules
135modname = $(basetarget)
136
137$(multi-objs-m)         : modname = $(modname-multi)
138$(multi-objs-m:.o=.i)   : modname = $(modname-multi)
139$(multi-objs-m:.o=.s)   : modname = $(modname-multi)
140$(multi-objs-m:.o=.lst) : modname = $(modname-multi)
141$(multi-objs-y)         : modname = $(modname-multi)
142$(multi-objs-y:.o=.i)   : modname = $(modname-multi)
143$(multi-objs-y:.o=.s)   : modname = $(modname-multi)
144$(multi-objs-y:.o=.lst) : modname = $(modname-multi)
145
146quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
147cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
148
149$(obj)/%.s: $(src)/%.c FORCE
150	$(call if_changed_dep,cc_s_c)
151
152quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
153cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
154
155$(obj)/%.i: $(src)/%.c FORCE
156	$(call if_changed_dep,cpp_i_c)
157
158# These mirror gensymtypes_S and co below, keep them in synch.
159cmd_gensymtypes_c =                                                         \
160    $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
161    $(GENKSYMS) $(if $(1), -T $(2))                                         \
162     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
163     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
164     $(if $(KBUILD_PRESERVE),-p)                                            \
165     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
166
167quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
168cmd_cc_symtypes_c =                                                         \
169    set -e;                                                                 \
170    $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
171    test -s $@ || rm -f $@
172
173$(obj)/%.symtypes : $(src)/%.c FORCE
174	$(call cmd,cc_symtypes_c)
175
176# LLVM assembly
177# Generate .ll files from .c
178quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
179      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
180
181$(obj)/%.ll: $(src)/%.c FORCE
182	$(call if_changed_dep,cc_ll_c)
183
184# C (.c) files
185# The C file is compiled and updated dependency information is generated.
186# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
187
188quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
189
190ifndef CONFIG_MODVERSIONS
191cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
192
193else
194# When module versioning is enabled the following steps are executed:
195# o compile a .tmp_<file>.o from <file>.c
196# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
197#   not export symbols, we just rename .tmp_<file>.o to <file>.o and
198#   are done.
199# o otherwise, we calculate symbol versions using the good old
200#   genksyms on the preprocessed source and postprocess them in a way
201#   that they are usable as a linker script
202# o generate <file>.o from .tmp_<file>.o using the linker to
203#   replace the unresolved symbols __crc_exported_symbol with
204#   the actual value of the checksum generated by genksyms
205
206cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
207
208cmd_modversions_c =								\
209	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
210		$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
211		    > $(@D)/.tmp_$(@F:.o=.ver);					\
212										\
213		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 			\
214			-T $(@D)/.tmp_$(@F:.o=.ver);				\
215		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);		\
216	else									\
217		mv -f $(@D)/.tmp_$(@F) $@;					\
218	fi;
219endif
220
221ifdef CONFIG_FTRACE_MCOUNT_RECORD
222ifdef BUILD_C_RECORDMCOUNT
223ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
224  RECORDMCOUNT_FLAGS = -w
225endif
226# Due to recursion, we must skip empty.o.
227# The empty.o file is created in the make process in order to determine
228# the target endianness and word size. It is made before all other C
229# files, including recordmcount.
230sub_cmd_record_mcount =					\
231	if [ $(@) != "scripts/mod/empty.o" ]; then	\
232		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\
233	fi;
234recordmcount_source := $(srctree)/scripts/recordmcount.c \
235		    $(srctree)/scripts/recordmcount.h
236else
237sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
238	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
239	"$(if $(CONFIG_64BIT),64,32)" \
240	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
241	"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
242	"$(if $(part-of-module),1,0)" "$(@)";
243recordmcount_source := $(srctree)/scripts/recordmcount.pl
244endif # BUILD_C_RECORDMCOUNT
245cmd_record_mcount =						\
246	if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =	\
247	     "$(CC_FLAGS_FTRACE)" ]; then			\
248		$(sub_cmd_record_mcount)			\
249	fi;
250endif # CONFIG_FTRACE_MCOUNT_RECORD
251
252ifdef CONFIG_STACK_VALIDATION
253ifneq ($(SKIP_STACK_VALIDATION),1)
254
255__objtool_obj := $(objtree)/tools/objtool/objtool
256
257objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
258
259ifndef CONFIG_FRAME_POINTER
260objtool_args += --no-fp
261endif
262ifdef CONFIG_GCOV_KERNEL
263objtool_args += --no-unreachable
264else
265objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
266endif
267
268ifdef CONFIG_MODVERSIONS
269objtool_o = $(@D)/.tmp_$(@F)
270else
271objtool_o = $(@)
272endif
273
274# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
275# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
276# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
277cmd_objtool = $(if $(patsubst y%,, \
278	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
279	$(__objtool_obj) $(objtool_args) "$(objtool_o)";)
280objtool_obj = $(if $(patsubst y%,, \
281	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
282	$(__objtool_obj))
283
284endif # SKIP_STACK_VALIDATION
285endif # CONFIG_STACK_VALIDATION
286
287# Rebuild all objects when objtool changes, or is enabled/disabled.
288objtool_dep = $(objtool_obj)					\
289	      $(wildcard include/config/orc/unwinder.h		\
290			 include/config/stack/validation.h)
291
292define rule_cc_o_c
293	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
294	$(call cmd_and_fixdep,cc_o_c)					  \
295	$(cmd_checkdoc)							  \
296	$(call echo-cmd,objtool) $(cmd_objtool)				  \
297	$(cmd_modversions_c)						  \
298	$(call echo-cmd,record_mcount) $(cmd_record_mcount)
299endef
300
301define rule_as_o_S
302	$(call cmd_and_fixdep,as_o_S)					  \
303	$(call echo-cmd,objtool) $(cmd_objtool)				  \
304	$(cmd_modversions_S)
305endef
306
307# List module undefined symbols (or empty line if not enabled)
308ifdef CONFIG_TRIM_UNUSED_KSYMS
309cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
310else
311cmd_undef_syms = echo
312endif
313
314# Built-in and composite module parts
315$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
316	$(call cmd,force_checksrc)
317	$(call if_changed_rule,cc_o_c)
318
319# Single-part modules are special since we need to mark them in $(MODVERDIR)
320
321$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
322	$(call cmd,force_checksrc)
323	$(call if_changed_rule,cc_o_c)
324	@{ echo $(@:.o=.ko); echo $@; \
325	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
326
327quiet_cmd_cc_lst_c = MKLST   $@
328      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
329		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
330				     System.map $(OBJDUMP) > $@
331
332$(obj)/%.lst: $(src)/%.c FORCE
333	$(call if_changed_dep,cc_lst_c)
334
335# Compile assembler sources (.S)
336# ---------------------------------------------------------------------------
337
338modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
339
340$(real-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
341$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
342
343# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
344# or a file that it includes, in order to get versioned symbols. We build a
345# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
346# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
347#
348# This is convoluted. The .S file must first be preprocessed to run guards and
349# expand names, then the resulting exports must be constructed into plain
350# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
351# to make the genksyms input.
352#
353# These mirror gensymtypes_c and co above, keep them in synch.
354cmd_gensymtypes_S =                                                         \
355    (echo "\#include <linux/kernel.h>" ;                                    \
356     echo "\#include <asm/asm-prototypes.h>" ;                              \
357    $(CPP) $(a_flags) $< |                                                  \
358     grep "\<___EXPORT_SYMBOL\>" |                                          \
359     sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
360    $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
361    $(GENKSYMS) $(if $(1), -T $(2))                                         \
362     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
363     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
364     $(if $(KBUILD_PRESERVE),-p)                                            \
365     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
366
367quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
368cmd_cc_symtypes_S =                                                         \
369    set -e;                                                                 \
370    $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
371    test -s $@ || rm -f $@
372
373$(obj)/%.symtypes : $(src)/%.S FORCE
374	$(call cmd,cc_symtypes_S)
375
376
377quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
378cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
379
380$(obj)/%.s: $(src)/%.S FORCE
381	$(call if_changed_dep,cpp_s_S)
382
383quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
384
385ifndef CONFIG_MODVERSIONS
386cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
387
388else
389
390ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
391
392ifeq ($(ASM_PROTOTYPES),)
393cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
394
395else
396
397# versioning matches the C process described above, with difference that
398# we parse asm-prototypes.h C header to get function definitions.
399
400cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
401
402cmd_modversions_S =								\
403	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
404		$(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
405		    > $(@D)/.tmp_$(@F:.o=.ver);					\
406										\
407		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 			\
408			-T $(@D)/.tmp_$(@F:.o=.ver);				\
409		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);		\
410	else									\
411		mv -f $(@D)/.tmp_$(@F) $@;					\
412	fi;
413endif
414endif
415
416$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
417	$(call if_changed_rule,as_o_S)
418
419targets += $(real-objs-y) $(real-objs-m) $(lib-y)
420targets += $(extra-y) $(MAKECMDGOALS) $(always)
421
422# Linker scripts preprocessor (.lds.S -> .lds)
423# ---------------------------------------------------------------------------
424quiet_cmd_cpp_lds_S = LDS     $@
425      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
426	                     -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
427
428$(obj)/%.lds: $(src)/%.lds.S FORCE
429	$(call if_changed_dep,cpp_lds_S)
430
431# ASN.1 grammar
432# ---------------------------------------------------------------------------
433quiet_cmd_asn1_compiler = ASN.1   $@
434      cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
435				$(subst .h,.c,$@) $(subst .c,.h,$@)
436
437.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
438
439$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
440	$(call cmd,asn1_compiler)
441
442# Build the compiled-in targets
443# ---------------------------------------------------------------------------
444
445# To build objects in subdirs, we need to descend into the directories
446$(sort $(subdir-obj-y)): $(subdir-ym) ;
447
448#
449# Rule to compile a set of .o files into one .o file
450#
451ifdef builtin-target
452
453ifdef CONFIG_THIN_ARCHIVES
454  cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
455  cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
456  quiet_cmd_link_o_target = AR      $@
457else
458  cmd_make_builtin = $(LD) $(ld_flags) -r -o
459  cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
460  quiet_cmd_link_o_target = LD      $@
461endif
462
463# If the list of objects to link is empty, just create an empty built-in.o
464cmd_link_o_target = $(if $(strip $(obj-y)),\
465		      $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
466		      $(cmd_secanalysis),\
467		      $(cmd_make_empty_builtin) $@)
468
469$(builtin-target): $(obj-y) FORCE
470	$(call if_changed,link_o_target)
471
472targets += $(builtin-target)
473endif # builtin-target
474
475#
476# Rule to create modules.order file
477#
478# Create commands to either record .ko file or cat modules.order from
479# a subdirectory
480modorder-cmds =						\
481	$(foreach m, $(modorder),			\
482		$(if $(filter %/modules.order, $m),	\
483			cat $m;, echo kernel/$m;))
484
485$(modorder-target): $(subdir-ym) FORCE
486	$(Q)(cat /dev/null; $(modorder-cmds)) > $@
487
488#
489# Rule to compile a set of .o files into one .a file
490#
491ifdef lib-target
492quiet_cmd_link_l_target = AR      $@
493
494ifdef CONFIG_THIN_ARCHIVES
495  cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
496else
497  cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
498endif
499
500$(lib-target): $(lib-y) FORCE
501	$(call if_changed,link_l_target)
502
503targets += $(lib-target)
504
505dummy-object = $(obj)/.lib_exports.o
506ksyms-lds = $(dot-target).lds
507ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
508ref_prefix = EXTERN(_
509else
510ref_prefix = EXTERN(
511endif
512
513quiet_cmd_export_list = EXPORTS $@
514cmd_export_list = $(OBJDUMP) -h $< | \
515	sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
516	rm -f $(dummy-object);\
517	echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
518	$(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
519	rm $(dummy-object) $(ksyms-lds)
520
521$(obj)/lib-ksyms.o: $(lib-target) FORCE
522	$(call if_changed,export_list)
523
524targets += $(obj)/lib-ksyms.o
525
526endif
527
528#
529# Rule to link composite objects
530#
531#  Composite objects are specified in kbuild makefile as follows:
532#    <composite-object>-objs := <list of .o files>
533#  or
534#    <composite-object>-y    := <list of .o files>
535#  or
536#    <composite-object>-m    := <list of .o files>
537#  The -m syntax only works if <composite object> is a module
538link_multi_deps =                     \
539$(filter $(addprefix $(obj)/,         \
540$($(subst $(obj)/,,$(@:.o=-objs)))    \
541$($(subst $(obj)/,,$(@:.o=-y)))       \
542$($(subst $(obj)/,,$(@:.o=-m)))), $^)
543
544cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
545
546ifdef CONFIG_THIN_ARCHIVES
547  quiet_cmd_link_multi-y = AR      $@
548  cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
549else
550  quiet_cmd_link_multi-y = LD      $@
551  cmd_link_multi-y = $(cmd_link_multi-link)
552endif
553
554quiet_cmd_link_multi-m = LD [M]  $@
555cmd_link_multi-m = $(cmd_link_multi-link)
556
557$(multi-used-y): FORCE
558	$(call if_changed,link_multi-y)
559$(call multi_depend, $(multi-used-y), .o, -objs -y)
560
561$(multi-used-m): FORCE
562	$(call if_changed,link_multi-m)
563	@{ echo $(@:.o=.ko); echo $(link_multi_deps); \
564	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
565$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
566
567targets += $(multi-used-y) $(multi-used-m)
568targets := $(filter-out $(PHONY), $(targets))
569
570# Descending
571# ---------------------------------------------------------------------------
572
573PHONY += $(subdir-ym)
574$(subdir-ym):
575	$(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1)
576
577# Add FORCE to the prequisites of a target to force it to be always rebuilt.
578# ---------------------------------------------------------------------------
579
580PHONY += FORCE
581
582FORCE:
583
584# Read all saved command lines and dependencies for the $(targets) we
585# may be building above, using $(if_changed{,_dep}). As an
586# optimization, we don't need to read them if the target does not
587# exist, we will rebuild anyway in that case.
588
589cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
590
591ifneq ($(cmd_files),)
592  include $(cmd_files)
593endif
594
595ifneq ($(KBUILD_SRC),)
596# Create directories for object files if they do not exist
597obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
598# If cmd_files exist, their directories apparently exist.  Skip mkdir.
599exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files))))
600obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs)))
601ifneq ($(obj-dirs),)
602$(shell mkdir -p $(obj-dirs))
603endif
604endif
605
606# Declare the contents of the .PHONY variable as phony.  We keep that
607# information in a variable se we can use it in if_changed and friends.
608
609.PHONY: $(PHONY)
610