mm, oom: do not rely on TIF_MEMDIE for memory reserves access
[linux/fpc-iii.git] / scripts / Makefile.build
blob2e3a10e79ca9ed645eaedbf0f8242332e96ba400
1 # ==========================================================================
2 # Building
3 # ==========================================================================
5 src := $(obj)
7 PHONY := __build
8 __build:
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
13 obj-y :=
14 obj-m :=
15 lib-y :=
16 lib-m :=
17 always :=
18 targets :=
19 subdir-y :=
20 subdir-m :=
21 EXTRA_AFLAGS   :=
22 EXTRA_CFLAGS   :=
23 EXTRA_CPPFLAGS :=
24 EXTRA_LDFLAGS  :=
25 asflags-y  :=
26 ccflags-y  :=
27 cppflags-y :=
28 ldflags-y  :=
30 subdir-asflags-y :=
31 subdir-ccflags-y :=
33 # Read auto.conf if it exists, otherwise ignore
34 -include include/config/auto.conf
36 include scripts/Kbuild.include
38 # For backward compatibility check that these variables do not change
39 save-cflags := $(CFLAGS)
41 # The filename Kbuild has precedence over Makefile
42 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
43 kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
44 include $(kbuild-file)
46 # If the save-* variables changed error out
47 ifeq ($(KBUILD_NOPEDANTIC),)
48         ifneq ("$(save-cflags)","$(CFLAGS)")
49                 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
50         endif
51 endif
53 include scripts/Makefile.lib
55 ifdef host-progs
56 ifneq ($(hostprogs-y),$(host-progs))
57 $(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
58 hostprogs-y += $(host-progs)
59 endif
60 endif
62 # Do not include host rules unless needed
63 ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
64 include scripts/Makefile.host
65 endif
67 ifneq ($(KBUILD_SRC),)
68 # Create output directory if not already present
69 _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
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)))
74 endif
76 ifndef obj
77 $(warning kbuild: Makefile.build is included improperly)
78 endif
80 # ===========================================================================
82 ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
83 lib-target := $(obj)/lib.a
84 obj-y += $(obj)/lib-ksyms.o
85 endif
87 ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
88 builtin-target := $(obj)/built-in.o
89 endif
91 modorder-target := $(obj)/modules.order
93 # We keep a list of all modules in $(MODVERDIR)
95 __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
96          $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
97          $(subdir-ym) $(always)
98         @:
100 # Linus' kernel sanity checking tool
101 ifneq ($(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
109 endif
111 # Do section mismatch analysis for each module/built-in.o
112 ifdef CONFIG_DEBUG_SECTION_MISMATCH
113   cmd_secanalysis = ; scripts/mod/modpost $@
114 endif
116 # Compile C sources (.c)
117 # ---------------------------------------------------------------------------
119 # Default is built-in, unless we know otherwise
120 modkern_cflags =                                          \
121         $(if $(part-of-module),                           \
122                 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
123                 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
124 quiet_modtag := $(empty)   $(empty)
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
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]
136 $(obj-m)              : quiet_modtag := [M]
138 # Default for not multi-part modules
139 modname = $(basetarget)
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)
150 quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
151 cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
153 $(obj)/%.s: $(src)/%.c FORCE
154         $(call if_changed_dep,cc_s_c)
156 quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
157 cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
159 $(obj)/%.i: $(src)/%.c FORCE
160         $(call if_changed_dep,cpp_i_c)
162 # These mirror gensymtypes_S and co below, keep them in synch.
163 cmd_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))
171 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
172 cmd_cc_symtypes_c =                                                         \
173     set -e;                                                                 \
174     $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
175     test -s $@ || rm -f $@
177 $(obj)/%.symtypes : $(src)/%.c FORCE
178         $(call cmd,cc_symtypes_c)
180 # LLVM assembly
181 # Generate .ll files from .c
182 quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
183       cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
185 $(obj)/%.ll: $(src)/%.c FORCE
186         $(call if_changed_dep,cc_ll_c)
188 # C (.c) files
189 # The C file is compiled and updated dependency information is generated.
190 # (See cmd_cc_o_c + relevant part of rule_cc_o_c)
192 quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
194 ifndef CONFIG_MODVERSIONS
195 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
197 else
198 # When module versioning is enabled the following steps are executed:
199 # o compile a .tmp_<file>.o from <file>.c
200 # o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
201 #   not export symbols, we just rename .tmp_<file>.o to <file>.o and
202 #   are done.
203 # o otherwise, we calculate symbol versions using the good old
204 #   genksyms on the preprocessed source and postprocess them in a way
205 #   that they are usable as a linker script
206 # o generate <file>.o from .tmp_<file>.o using the linker to
207 #   replace the unresolved symbols __crc_exported_symbol with
208 #   the actual value of the checksum generated by genksyms
210 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
212 cmd_modversions_c =                                                             \
213         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
214                 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
215                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
216                                                                                 \
217                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
218                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
219                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
220         else                                                                    \
221                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
222         fi;
223 endif
225 ifdef CONFIG_FTRACE_MCOUNT_RECORD
226 ifdef BUILD_C_RECORDMCOUNT
227 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
228   RECORDMCOUNT_FLAGS = -w
229 endif
230 # Due to recursion, we must skip empty.o.
231 # The empty.o file is created in the make process in order to determine
232 # the target endianness and word size. It is made before all other C
233 # files, including recordmcount.
234 sub_cmd_record_mcount =                                 \
235         if [ $(@) != "scripts/mod/empty.o" ]; then      \
236                 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";   \
237         fi;
238 recordmcount_source := $(srctree)/scripts/recordmcount.c \
239                     $(srctree)/scripts/recordmcount.h
240 else
241 sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
242         "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
243         "$(if $(CONFIG_64BIT),64,32)" \
244         "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
245         "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
246         "$(if $(part-of-module),1,0)" "$(@)";
247 recordmcount_source := $(srctree)/scripts/recordmcount.pl
248 endif # BUILD_C_RECORDMCOUNT
249 cmd_record_mcount =                                             \
250         if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =   \
251              "$(CC_FLAGS_FTRACE)" ]; then                       \
252                 $(sub_cmd_record_mcount)                        \
253         fi;
254 endif # CONFIG_FTRACE_MCOUNT_RECORD
256 ifdef CONFIG_STACK_VALIDATION
257 ifneq ($(SKIP_STACK_VALIDATION),1)
259 __objtool_obj := $(objtree)/tools/objtool/objtool
261 objtool_args = $(if $(CONFIG_ORC_UNWINDER),orc generate,check)
263 ifndef CONFIG_FRAME_POINTER
264 objtool_args += --no-fp
265 endif
266 ifdef CONFIG_GCOV_KERNEL
267 objtool_args += --no-unreachable
268 endif
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
273 cmd_objtool = $(if $(patsubst y%,, \
274         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
275         $(__objtool_obj) $(objtool_args) "$(@)";)
276 objtool_obj = $(if $(patsubst y%,, \
277         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
278         $(__objtool_obj))
280 endif # SKIP_STACK_VALIDATION
281 endif # CONFIG_STACK_VALIDATION
283 # Rebuild all objects when objtool changes, or is enabled/disabled.
284 objtool_dep = $(objtool_obj)                                    \
285               $(wildcard include/config/orc/unwinder.h          \
286                          include/config/stack/validation.h)
288 define rule_cc_o_c
289         $(call echo-cmd,checksrc) $(cmd_checksrc)                         \
290         $(call cmd_and_fixdep,cc_o_c)                                     \
291         $(cmd_modversions_c)                                              \
292         $(call echo-cmd,objtool) $(cmd_objtool)                           \
293         $(call echo-cmd,record_mcount) $(cmd_record_mcount)
294 endef
296 define rule_as_o_S
297         $(call cmd_and_fixdep,as_o_S)                                     \
298         $(cmd_modversions_S)                                              \
299         $(call echo-cmd,objtool) $(cmd_objtool)
300 endef
302 # List module undefined symbols (or empty line if not enabled)
303 ifdef CONFIG_TRIM_UNUSED_KSYMS
304 cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
305 else
306 cmd_undef_syms = echo
307 endif
309 # Built-in and composite module parts
310 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
311         $(call cmd,force_checksrc)
312         $(call if_changed_rule,cc_o_c)
314 # Single-part modules are special since we need to mark them in $(MODVERDIR)
316 $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
317         $(call cmd,force_checksrc)
318         $(call if_changed_rule,cc_o_c)
319         @{ echo $(@:.o=.ko); echo $@; \
320            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
322 quiet_cmd_cc_lst_c = MKLST   $@
323       cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
324                      $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
325                                      System.map $(OBJDUMP) > $@
327 $(obj)/%.lst: $(src)/%.c FORCE
328         $(call if_changed_dep,cc_lst_c)
330 # Compile assembler sources (.S)
331 # ---------------------------------------------------------------------------
333 modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
335 $(real-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
336 $(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
338 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
339 # or a file that it includes, in order to get versioned symbols. We build a
340 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
341 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
343 # This is convoluted. The .S file must first be preprocessed to run guards and
344 # expand names, then the resulting exports must be constructed into plain
345 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
346 # to make the genksyms input.
348 # These mirror gensymtypes_c and co above, keep them in synch.
349 cmd_gensymtypes_S =                                                         \
350     (echo "\#include <linux/kernel.h>" ;                                    \
351      echo "\#include <asm/asm-prototypes.h>" ;                              \
352     $(CPP) $(a_flags) $< |                                                  \
353      grep "\<___EXPORT_SYMBOL\>" |                                          \
354      sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
355     $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
356     $(GENKSYMS) $(if $(1), -T $(2))                                         \
357      $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
358      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
359      $(if $(KBUILD_PRESERVE),-p)                                            \
360      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
362 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
363 cmd_cc_symtypes_S =                                                         \
364     set -e;                                                                 \
365     $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
366     test -s $@ || rm -f $@
368 $(obj)/%.symtypes : $(src)/%.S FORCE
369         $(call cmd,cc_symtypes_S)
372 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
373 cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
375 $(obj)/%.s: $(src)/%.S FORCE
376         $(call if_changed_dep,cpp_s_S)
378 quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
380 ifndef CONFIG_MODVERSIONS
381 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
383 else
385 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
387 ifeq ($(ASM_PROTOTYPES),)
388 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
390 else
392 # versioning matches the C process described above, with difference that
393 # we parse asm-prototypes.h C header to get function definitions.
395 cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
397 cmd_modversions_S =                                                             \
398         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
399                 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
400                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
401                                                                                 \
402                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
403                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
404                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
405         else                                                                    \
406                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
407         fi;
408 endif
409 endif
411 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
412         $(call if_changed_rule,as_o_S)
414 targets += $(real-objs-y) $(real-objs-m) $(lib-y)
415 targets += $(extra-y) $(MAKECMDGOALS) $(always)
417 # Linker scripts preprocessor (.lds.S -> .lds)
418 # ---------------------------------------------------------------------------
419 quiet_cmd_cpp_lds_S = LDS     $@
420       cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
421                              -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
423 $(obj)/%.lds: $(src)/%.lds.S FORCE
424         $(call if_changed_dep,cpp_lds_S)
426 # ASN.1 grammar
427 # ---------------------------------------------------------------------------
428 quiet_cmd_asn1_compiler = ASN.1   $@
429       cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
430                                 $(subst .h,.c,$@) $(subst .c,.h,$@)
432 .PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
434 $(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
435         $(call cmd,asn1_compiler)
437 # Build the compiled-in targets
438 # ---------------------------------------------------------------------------
440 # To build objects in subdirs, we need to descend into the directories
441 $(sort $(subdir-obj-y)): $(subdir-ym) ;
444 # Rule to compile a set of .o files into one .o file
446 ifdef builtin-target
448 ifdef CONFIG_THIN_ARCHIVES
449   cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
450   cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
451   quiet_cmd_link_o_target = AR      $@
452 else
453   cmd_make_builtin = $(LD) $(ld_flags) -r -o
454   cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
455   quiet_cmd_link_o_target = LD      $@
456 endif
458 # If the list of objects to link is empty, just create an empty built-in.o
459 cmd_link_o_target = $(if $(strip $(obj-y)),\
460                       $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
461                       $(cmd_secanalysis),\
462                       $(cmd_make_empty_builtin) $@)
464 $(builtin-target): $(obj-y) FORCE
465         $(call if_changed,link_o_target)
467 targets += $(builtin-target)
468 endif # builtin-target
471 # Rule to create modules.order file
473 # Create commands to either record .ko file or cat modules.order from
474 # a subdirectory
475 modorder-cmds =                                         \
476         $(foreach m, $(modorder),                       \
477                 $(if $(filter %/modules.order, $m),     \
478                         cat $m;, echo kernel/$m;))
480 $(modorder-target): $(subdir-ym) FORCE
481         $(Q)(cat /dev/null; $(modorder-cmds)) > $@
484 # Rule to compile a set of .o files into one .a file
486 ifdef lib-target
487 quiet_cmd_link_l_target = AR      $@
489 ifdef CONFIG_THIN_ARCHIVES
490   cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
491 else
492   cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
493 endif
495 $(lib-target): $(lib-y) FORCE
496         $(call if_changed,link_l_target)
498 targets += $(lib-target)
500 dummy-object = $(obj)/.lib_exports.o
501 ksyms-lds = $(dot-target).lds
502 ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
503 ref_prefix = EXTERN(_
504 else
505 ref_prefix = EXTERN(
506 endif
508 quiet_cmd_export_list = EXPORTS $@
509 cmd_export_list = $(OBJDUMP) -h $< | \
510         sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
511         rm -f $(dummy-object);\
512         echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
513         $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
514         rm $(dummy-object) $(ksyms-lds)
516 $(obj)/lib-ksyms.o: $(lib-target) FORCE
517         $(call if_changed,export_list)
519 targets += $(obj)/lib-ksyms.o
521 endif
524 # Rule to link composite objects
526 #  Composite objects are specified in kbuild makefile as follows:
527 #    <composite-object>-objs := <list of .o files>
528 #  or
529 #    <composite-object>-y    := <list of .o files>
530 #  or
531 #    <composite-object>-m    := <list of .o files>
532 #  The -m syntax only works if <composite object> is a module
533 link_multi_deps =                     \
534 $(filter $(addprefix $(obj)/,         \
535 $($(subst $(obj)/,,$(@:.o=-objs)))    \
536 $($(subst $(obj)/,,$(@:.o=-y)))       \
537 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
539 cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
541 ifdef CONFIG_THIN_ARCHIVES
542   quiet_cmd_link_multi-y = AR      $@
543   cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
544 else
545   quiet_cmd_link_multi-y = LD      $@
546   cmd_link_multi-y = $(cmd_link_multi-link)
547 endif
549 quiet_cmd_link_multi-m = LD [M]  $@
550 cmd_link_multi-m = $(cmd_link_multi-link)
552 $(multi-used-y): FORCE
553         $(call if_changed,link_multi-y)
554 $(call multi_depend, $(multi-used-y), .o, -objs -y)
556 $(multi-used-m): FORCE
557         $(call if_changed,link_multi-m)
558         @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
559            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
560 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
562 targets += $(multi-used-y) $(multi-used-m)
565 # Descending
566 # ---------------------------------------------------------------------------
568 PHONY += $(subdir-ym)
569 $(subdir-ym):
570         $(Q)$(MAKE) $(build)=$@
572 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
573 # ---------------------------------------------------------------------------
575 PHONY += FORCE
577 FORCE:
579 # Read all saved command lines and dependencies for the $(targets) we
580 # may be building above, using $(if_changed{,_dep}). As an
581 # optimization, we don't need to read them if the target does not
582 # exist, we will rebuild anyway in that case.
584 targets := $(wildcard $(sort $(targets)))
585 cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
587 ifneq ($(cmd_files),)
588   include $(cmd_files)
589 endif
591 # Declare the contents of the .PHONY variable as phony.  We keep that
592 # information in a variable se we can use it in if_changed and friends.
594 .PHONY: $(PHONY)