xref: /openbmc/linux/scripts/Makefile.build (revision 2eb3ed33e55d003d721d4d1a5e72fe323c12b4c0)
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)$(hostcxxlibs-m),)
65include scripts/Makefile.host
66endif
67
68ifneq ($(KBUILD_SRC),)
69# Create output directory if not already present
70_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
71
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 $(d)))
75endif
76
77ifndef obj
78$(warning kbuild: Makefile.build is included improperly)
79endif
80
81# ===========================================================================
82
83ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
84lib-target := $(obj)/lib.a
85obj-y += $(obj)/lib-ksyms.o
86endif
87
88ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
89builtin-target := $(obj)/built-in.o
90endif
91
92modorder-target := $(obj)/modules.order
93
94# We keep a list of all modules in $(MODVERDIR)
95
96__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
97	 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
98	 $(subdir-ym) $(always)
99	@:
100
101# Linus' kernel sanity checking tool
102ifneq ($(KBUILD_CHECKSRC),0)
103  ifeq ($(KBUILD_CHECKSRC),2)
104    quiet_cmd_force_checksrc = CHECK   $<
105          cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
106  else
107      quiet_cmd_checksrc     = CHECK   $<
108            cmd_checksrc     = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
109  endif
110endif
111
112# Do section mismatch analysis for each module/built-in.o
113ifdef CONFIG_DEBUG_SECTION_MISMATCH
114  cmd_secanalysis = ; scripts/mod/modpost $@
115endif
116
117# Compile C sources (.c)
118# ---------------------------------------------------------------------------
119
120# Default is built-in, unless we know otherwise
121modkern_cflags =                                          \
122	$(if $(part-of-module),                           \
123		$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
124		$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
125quiet_modtag := $(empty)   $(empty)
126
127$(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$(real-objs-m:.o=.lst): part-of-module := y
131
132$(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$(real-objs-m:.o=.lst): quiet_modtag := [M]
136
137$(obj-m)              : quiet_modtag := [M]
138
139# Default for not multi-part modules
140modname = $(basetarget)
141
142$(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)
150
151quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
152cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
153
154$(obj)/%.s: $(src)/%.c FORCE
155	$(call if_changed_dep,cc_s_c)
156
157quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
158cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
159
160$(obj)/%.i: $(src)/%.c FORCE
161	$(call if_changed_dep,cpp_i_c)
162
163# These mirror gensymtypes_S and co below, keep them in synch.
164cmd_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))
171
172quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
173cmd_cc_symtypes_c =                                                         \
174    set -e;                                                                 \
175    $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
176    test -s $@ || rm -f $@
177
178$(obj)/%.symtypes : $(src)/%.c FORCE
179	$(call cmd,cc_symtypes_c)
180
181# LLVM assembly
182# Generate .ll files from .c
183quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
184      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
185
186$(obj)/%.ll: $(src)/%.c FORCE
187	$(call if_changed_dep,cc_ll_c)
188
189# C (.c) files
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)
192
193quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
194
195ifndef CONFIG_MODVERSIONS
196cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
197
198else
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
203#   are done.
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
210
211cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
212
213cmd_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);					\
217										\
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);		\
221	else									\
222		mv -f $(@D)/.tmp_$(@F) $@;					\
223	fi;
224endif
225
226ifdef CONFIG_FTRACE_MCOUNT_RECORD
227ifdef BUILD_C_RECORDMCOUNT
228ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
229  RECORDMCOUNT_FLAGS = -w
230endif
231# Due to recursion, we must skip empty.o.
232# The empty.o file is created in the make process in order to determine
233# the target endianness and word size. It is made before all other C
234# files, including recordmcount.
235sub_cmd_record_mcount =					\
236	if [ $(@) != "scripts/mod/empty.o" ]; then	\
237		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\
238	fi;
239recordmcount_source := $(srctree)/scripts/recordmcount.c \
240		    $(srctree)/scripts/recordmcount.h
241else
242sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
243	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
244	"$(if $(CONFIG_64BIT),64,32)" \
245	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
246	"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
247	"$(if $(part-of-module),1,0)" "$(@)";
248recordmcount_source := $(srctree)/scripts/recordmcount.pl
249endif # BUILD_C_RECORDMCOUNT
250cmd_record_mcount =						\
251	if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =	\
252	     "$(CC_FLAGS_FTRACE)" ]; then			\
253		$(sub_cmd_record_mcount)			\
254	fi;
255endif # CONFIG_FTRACE_MCOUNT_RECORD
256
257ifdef CONFIG_STACK_VALIDATION
258ifneq ($(SKIP_STACK_VALIDATION),1)
259
260__objtool_obj := $(objtree)/tools/objtool/objtool
261
262objtool_args = $(if $(CONFIG_ORC_UNWINDER),orc generate,check)
263
264ifndef CONFIG_FRAME_POINTER
265objtool_args += --no-fp
266endif
267ifdef CONFIG_GCOV_KERNEL
268objtool_args += --no-unreachable
269else
270objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
271endif
272
273# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
274# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
275# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
276cmd_objtool = $(if $(patsubst y%,, \
277	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
278	$(__objtool_obj) $(objtool_args) "$(@)";)
279objtool_obj = $(if $(patsubst y%,, \
280	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
281	$(__objtool_obj))
282
283endif # SKIP_STACK_VALIDATION
284endif # CONFIG_STACK_VALIDATION
285
286# Rebuild all objects when objtool changes, or is enabled/disabled.
287objtool_dep = $(objtool_obj)					\
288	      $(wildcard include/config/orc/unwinder.h		\
289			 include/config/stack/validation.h)
290
291define rule_cc_o_c
292	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
293	$(call cmd_and_fixdep,cc_o_c)					  \
294	$(cmd_modversions_c)						  \
295	$(call echo-cmd,objtool) $(cmd_objtool)				  \
296	$(call echo-cmd,record_mcount) $(cmd_record_mcount)
297endef
298
299define rule_as_o_S
300	$(call cmd_and_fixdep,as_o_S)					  \
301	$(cmd_modversions_S)						  \
302	$(call echo-cmd,objtool) $(cmd_objtool)
303endef
304
305# List module undefined symbols (or empty line if not enabled)
306ifdef CONFIG_TRIM_UNUSED_KSYMS
307cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
308else
309cmd_undef_syms = echo
310endif
311
312# Built-in and composite module parts
313$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
314	$(call cmd,force_checksrc)
315	$(call if_changed_rule,cc_o_c)
316
317# Single-part modules are special since we need to mark them in $(MODVERDIR)
318
319$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
320	$(call cmd,force_checksrc)
321	$(call if_changed_rule,cc_o_c)
322	@{ echo $(@:.o=.ko); echo $@; \
323	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
324
325quiet_cmd_cc_lst_c = MKLST   $@
326      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
327		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
328				     System.map $(OBJDUMP) > $@
329
330$(obj)/%.lst: $(src)/%.c FORCE
331	$(call if_changed_dep,cc_lst_c)
332
333# Compile assembler sources (.S)
334# ---------------------------------------------------------------------------
335
336modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
337
338$(real-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
339$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
340
341# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
342# or a file that it includes, in order to get versioned symbols. We build a
343# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
344# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
345#
346# This is convoluted. The .S file must first be preprocessed to run guards and
347# expand names, then the resulting exports must be constructed into plain
348# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
349# to make the genksyms input.
350#
351# These mirror gensymtypes_c and co above, keep them in synch.
352cmd_gensymtypes_S =                                                         \
353    (echo "\#include <linux/kernel.h>" ;                                    \
354     echo "\#include <asm/asm-prototypes.h>" ;                              \
355    $(CPP) $(a_flags) $< |                                                  \
356     grep "\<___EXPORT_SYMBOL\>" |                                          \
357     sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
358    $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
359    $(GENKSYMS) $(if $(1), -T $(2))                                         \
360     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
361     $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
362     $(if $(KBUILD_PRESERVE),-p)                                            \
363     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
364
365quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
366cmd_cc_symtypes_S =                                                         \
367    set -e;                                                                 \
368    $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
369    test -s $@ || rm -f $@
370
371$(obj)/%.symtypes : $(src)/%.S FORCE
372	$(call cmd,cc_symtypes_S)
373
374
375quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
376cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
377
378$(obj)/%.s: $(src)/%.S FORCE
379	$(call if_changed_dep,cpp_s_S)
380
381quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
382
383ifndef CONFIG_MODVERSIONS
384cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
385
386else
387
388ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
389
390ifeq ($(ASM_PROTOTYPES),)
391cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
392
393else
394
395# versioning matches the C process described above, with difference that
396# we parse asm-prototypes.h C header to get function definitions.
397
398cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
399
400cmd_modversions_S =								\
401	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
402		$(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
403		    > $(@D)/.tmp_$(@F:.o=.ver);					\
404										\
405		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 			\
406			-T $(@D)/.tmp_$(@F:.o=.ver);				\
407		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);		\
408	else									\
409		mv -f $(@D)/.tmp_$(@F) $@;					\
410	fi;
411endif
412endif
413
414$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
415	$(call if_changed_rule,as_o_S)
416
417targets += $(real-objs-y) $(real-objs-m) $(lib-y)
418targets += $(extra-y) $(MAKECMDGOALS) $(always)
419
420# Linker scripts preprocessor (.lds.S -> .lds)
421# ---------------------------------------------------------------------------
422quiet_cmd_cpp_lds_S = LDS     $@
423      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
424	                     -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
425
426$(obj)/%.lds: $(src)/%.lds.S FORCE
427	$(call if_changed_dep,cpp_lds_S)
428
429# ASN.1 grammar
430# ---------------------------------------------------------------------------
431quiet_cmd_asn1_compiler = ASN.1   $@
432      cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
433				$(subst .h,.c,$@) $(subst .c,.h,$@)
434
435.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
436
437$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
438	$(call cmd,asn1_compiler)
439
440# Build the compiled-in targets
441# ---------------------------------------------------------------------------
442
443# To build objects in subdirs, we need to descend into the directories
444$(sort $(subdir-obj-y)): $(subdir-ym) ;
445
446#
447# Rule to compile a set of .o files into one .o file
448#
449ifdef builtin-target
450
451ifdef CONFIG_THIN_ARCHIVES
452  cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
453  cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
454  quiet_cmd_link_o_target = AR      $@
455else
456  cmd_make_builtin = $(LD) $(ld_flags) -r -o
457  cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
458  quiet_cmd_link_o_target = LD      $@
459endif
460
461# If the list of objects to link is empty, just create an empty built-in.o
462cmd_link_o_target = $(if $(strip $(obj-y)),\
463		      $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
464		      $(cmd_secanalysis),\
465		      $(cmd_make_empty_builtin) $@)
466
467$(builtin-target): $(obj-y) FORCE
468	$(call if_changed,link_o_target)
469
470targets += $(builtin-target)
471endif # builtin-target
472
473#
474# Rule to create modules.order file
475#
476# Create commands to either record .ko file or cat modules.order from
477# a subdirectory
478modorder-cmds =						\
479	$(foreach m, $(modorder),			\
480		$(if $(filter %/modules.order, $m),	\
481			cat $m;, echo kernel/$m;))
482
483$(modorder-target): $(subdir-ym) FORCE
484	$(Q)(cat /dev/null; $(modorder-cmds)) > $@
485
486#
487# Rule to compile a set of .o files into one .a file
488#
489ifdef lib-target
490quiet_cmd_link_l_target = AR      $@
491
492ifdef CONFIG_THIN_ARCHIVES
493  cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
494else
495  cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
496endif
497
498$(lib-target): $(lib-y) FORCE
499	$(call if_changed,link_l_target)
500
501targets += $(lib-target)
502
503dummy-object = $(obj)/.lib_exports.o
504ksyms-lds = $(dot-target).lds
505ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
506ref_prefix = EXTERN(_
507else
508ref_prefix = EXTERN(
509endif
510
511quiet_cmd_export_list = EXPORTS $@
512cmd_export_list = $(OBJDUMP) -h $< | \
513	sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
514	rm -f $(dummy-object);\
515	echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
516	$(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
517	rm $(dummy-object) $(ksyms-lds)
518
519$(obj)/lib-ksyms.o: $(lib-target) FORCE
520	$(call if_changed,export_list)
521
522targets += $(obj)/lib-ksyms.o
523
524endif
525
526#
527# Rule to link composite objects
528#
529#  Composite objects are specified in kbuild makefile as follows:
530#    <composite-object>-objs := <list of .o files>
531#  or
532#    <composite-object>-y    := <list of .o files>
533#  or
534#    <composite-object>-m    := <list of .o files>
535#  The -m syntax only works if <composite object> is a module
536link_multi_deps =                     \
537$(filter $(addprefix $(obj)/,         \
538$($(subst $(obj)/,,$(@:.o=-objs)))    \
539$($(subst $(obj)/,,$(@:.o=-y)))       \
540$($(subst $(obj)/,,$(@:.o=-m)))), $^)
541
542cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
543
544ifdef CONFIG_THIN_ARCHIVES
545  quiet_cmd_link_multi-y = AR      $@
546  cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
547else
548  quiet_cmd_link_multi-y = LD      $@
549  cmd_link_multi-y = $(cmd_link_multi-link)
550endif
551
552quiet_cmd_link_multi-m = LD [M]  $@
553cmd_link_multi-m = $(cmd_link_multi-link)
554
555$(multi-used-y): FORCE
556	$(call if_changed,link_multi-y)
557$(call multi_depend, $(multi-used-y), .o, -objs -y)
558
559$(multi-used-m): FORCE
560	$(call if_changed,link_multi-m)
561	@{ echo $(@:.o=.ko); echo $(link_multi_deps); \
562	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
563$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
564
565targets += $(multi-used-y) $(multi-used-m)
566
567
568# Descending
569# ---------------------------------------------------------------------------
570
571PHONY += $(subdir-ym)
572$(subdir-ym):
573	$(Q)$(MAKE) $(build)=$@
574
575# Add FORCE to the prequisites of a target to force it to be always rebuilt.
576# ---------------------------------------------------------------------------
577
578PHONY += FORCE
579
580FORCE:
581
582# Read all saved command lines and dependencies for the $(targets) we
583# may be building above, using $(if_changed{,_dep}). As an
584# optimization, we don't need to read them if the target does not
585# exist, we will rebuild anyway in that case.
586
587targets := $(wildcard $(sort $(targets)))
588cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
589
590ifneq ($(cmd_files),)
591  include $(cmd_files)
592endif
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