scripts/Makefile.build

   1 # SPDX-License-Identifier: GPL-2.0
   2 # ==========================================================================
   3 # Building
   4 # ==========================================================================
   5
   6 src := $(obj)
   7
   8 PHONY := __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
  14 obj-y :=
  15 obj-m :=
  16 lib-y :=
  17 lib-m :=
  18 always :=
  19 targets :=
  20 subdir-y :=
  21 subdir-m :=
  22 EXTRA_AFLAGS   :=
  23 EXTRA_CFLAGS   :=
  24 EXTRA_CPPFLAGS :=
  25 EXTRA_LDFLAGS  :=
  26 asflags-y  :=
  27 ccflags-y  :=
  28 cppflags-y :=
  29 ldflags-y  :=
  30
  31 subdir-asflags-y :=
  32 subdir-ccflags-y :=
  33
  34 # Read auto.conf if it exists, otherwise ignore
  35 -include include/config/auto.conf
  36
  37 include scripts/Kbuild.include
  38
  39 # For backward compatibility check that these variables do not change
  40 save-cflags := $(CFLAGS)
  41
  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 $(kbuild-file)
  46
  47 # If the save-* variables changed error out
  48 ifeq ($(KBUILD_NOPEDANTIC),)
  49         ifneq ("$(save-cflags)","$(CFLAGS)")
  50                 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
  51         endif
  52 endif
  53
  54 include scripts/Makefile.lib
  55
  56 ifdef host-progs
  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 += $(host-progs)
  60 endif
  61 endif
  62
  63 # Do not include host rules unless needed
  64 ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
  65 include scripts/Makefile.host
  66 endif
  67
  68 ifneq ($(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)))
  75 endif
  76
  77 ifndef obj
  78 $(warning kbuild: Makefile.build is included improperly)
  79 endif
  80
  81 # ===========================================================================
  82
  83 ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
  84 lib-target := $(obj)/lib.a
  85 obj-y += $(obj)/lib-ksyms.o
  86 endif
  87
  88 ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
  89 builtin-target := $(obj)/built-in.o
  90 endif
  91
  92 modorder-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) $(always)
  99         @:
 100
 101 # Linus' kernel sanity checking tool
 102 ifneq ($(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
 110 endif
 111
 112 # Do section mismatch analysis for each module/built-in.o
 113 ifdef CONFIG_DEBUG_SECTION_MISMATCH
 114   cmd_secanalysis = ; scripts/mod/modpost $@
 115 endif
 116
 117 # Compile C sources (.c)
 118 # ---------------------------------------------------------------------------
 119
 120 # Default is built-in, unless we know otherwise
 121 modkern_cflags =                                          \
 122         $(if $(part-of-module),                           \
 123                 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
 124                 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
 125 quiet_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
 140 modname = $(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
 151 quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
 152 cmd_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
 157 quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
 158 cmd_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.
 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))
 171
 172 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
 173 cmd_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
 183 quiet_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
 193 quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
 194
 195 ifndef CONFIG_MODVERSIONS
 196 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
 197
 198 else
 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
 211 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
 212
 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);                                 \
 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) $@;                                      \
 223         fi;
 224 endif
 225
 226 ifdef CONFIG_FTRACE_MCOUNT_RECORD
 227 ifdef BUILD_C_RECORDMCOUNT
 228 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
 229   RECORDMCOUNT_FLAGS = -w
 230 endif
 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.
 235 sub_cmd_record_mcount =                                 \
 236         if [ $(@) != "scripts/mod/empty.o" ]; then      \
 237                 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";   \
 238         fi;
 239 recordmcount_source := $(srctree)/scripts/recordmcount.c \
 240                     $(srctree)/scripts/recordmcount.h
 241 else
 242 sub_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 $(part-of-module),1,0)" "$(@)";
 248 recordmcount_source := $(srctree)/scripts/recordmcount.pl
 249 endif # BUILD_C_RECORDMCOUNT
 250 cmd_record_mcount =                                             \
 251         if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =   \
 252              "$(CC_FLAGS_FTRACE)" ]; then                       \
 253                 $(sub_cmd_record_mcount)                        \
 254         fi;
 255 endif # CONFIG_FTRACE_MCOUNT_RECORD
 256
 257 ifdef CONFIG_STACK_VALIDATION
 258 ifneq ($(SKIP_STACK_VALIDATION),1)
 259
 260 __objtool_obj := $(objtree)/tools/objtool/objtool
 261
 262 objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
 263
 264 objtool_args += $(if $(part-of-module), --module,)
 265
 266 ifndef CONFIG_FRAME_POINTER
 267 objtool_args += --no-fp
 268 endif
 269 ifdef CONFIG_GCOV_KERNEL
 270 objtool_args += --no-unreachable
 271 else
 272 objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
 273 endif
 274 ifdef CONFIG_RETPOLINE
 275 ifneq ($(RETPOLINE_CFLAGS),)
 276   objtool_args += --retpoline
 277 endif
 278 endif
 279
 280
 281 ifdef CONFIG_MODVERSIONS
 282 objtool_o = $(@D)/.tmp_$(@F)
 283 else
 284 objtool_o = $(@)
 285 endif
 286
 287 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
 288 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
 289 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
 290 cmd_objtool = $(if $(patsubst y%,, \
 291         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 292         $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
 293 objtool_obj = $(if $(patsubst y%,, \
 294         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 295         $(__objtool_obj))
 296
 297 endif # SKIP_STACK_VALIDATION
 298 endif # CONFIG_STACK_VALIDATION
 299
 300 # Rebuild all objects when objtool changes, or is enabled/disabled.
 301 objtool_dep = $(objtool_obj)                                    \
 302               $(wildcard include/config/orc/unwinder.h          \
 303                          include/config/stack/validation.h)
 304
 305 define rule_cc_o_c
 306         $(call echo-cmd,checksrc) $(cmd_checksrc)                         \
 307         $(call cmd_and_fixdep,cc_o_c)                                     \
 308         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 309         $(cmd_modversions_c)                                              \
 310         $(call echo-cmd,record_mcount) $(cmd_record_mcount)
 311 endef
 312
 313 define rule_as_o_S
 314         $(call cmd_and_fixdep,as_o_S)                                     \
 315         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 316         $(cmd_modversions_S)
 317 endef
 318
 319 # List module undefined symbols (or empty line if not enabled)
 320 ifdef CONFIG_TRIM_UNUSED_KSYMS
 321 cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
 322 else
 323 cmd_undef_syms = echo
 324 endif
 325
 326 # Built-in and composite module parts
 327 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 328         $(call cmd,force_checksrc)
 329         $(call if_changed_rule,cc_o_c)
 330
 331 # Single-part modules are special since we need to mark them in $(MODVERDIR)
 332
 333 $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 334         $(call cmd,force_checksrc)
 335         $(call if_changed_rule,cc_o_c)
 336         @{ echo $(@:.o=.ko); echo $@; \
 337            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 338
 339 quiet_cmd_cc_lst_c = MKLST   $@
 340       cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
 341                      $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
 342                                      System.map $(OBJDUMP) > $@
 343
 344 $(obj)/%.lst: $(src)/%.c FORCE
 345         $(call if_changed_dep,cc_lst_c)
 346
 347 # Compile assembler sources (.S)
 348 # ---------------------------------------------------------------------------
 349
 350 modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
 351
 352 $(real-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 353 $(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 354
 355 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
 356 # or a file that it includes, in order to get versioned symbols. We build a
 357 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
 358 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
 359 #
 360 # This is convoluted. The .S file must first be preprocessed to run guards and
 361 # expand names, then the resulting exports must be constructed into plain
 362 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
 363 # to make the genksyms input.
 364 #
 365 # These mirror gensymtypes_c and co above, keep them in synch.
 366 cmd_gensymtypes_S =                                                         \
 367     (echo "\#include <linux/kernel.h>" ;                                    \
 368      echo "\#include <asm/asm-prototypes.h>" ;                              \
 369     $(CPP) $(a_flags) $< |                                                  \
 370      grep "\<___EXPORT_SYMBOL\>" |                                          \
 371      sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
 372     $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
 373     $(GENKSYMS) $(if $(1), -T $(2))                                         \
 374      $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
 375      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
 376      $(if $(KBUILD_PRESERVE),-p)                                            \
 377      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 378
 379 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
 380 cmd_cc_symtypes_S =                                                         \
 381     set -e;                                                                 \
 382     $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
 383     test -s $@ || rm -f $@
 384
 385 $(obj)/%.symtypes : $(src)/%.S FORCE
 386         $(call cmd,cc_symtypes_S)
 387
 388
 389 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
 390 cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
 391
 392 $(obj)/%.s: $(src)/%.S FORCE
 393         $(call if_changed_dep,cpp_s_S)
 394
 395 quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
 396
 397 ifndef CONFIG_MODVERSIONS
 398 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 399
 400 else
 401
 402 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
 403
 404 ifeq ($(ASM_PROTOTYPES),)
 405 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 406
 407 else
 408
 409 # versioning matches the C process described above, with difference that
 410 # we parse asm-prototypes.h C header to get function definitions.
 411
 412 cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
 413
 414 cmd_modversions_S =                                                             \
 415         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 416                 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 417                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 418                                                                                 \
 419                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
 420                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 421                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 422         else                                                                    \
 423                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 424         fi;
 425 endif
 426 endif
 427
 428 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
 429         $(call if_changed_rule,as_o_S)
 430
 431 targets += $(real-objs-y) $(real-objs-m) $(lib-y)
 432 targets += $(extra-y) $(MAKECMDGOALS) $(always)
 433
 434 # Linker scripts preprocessor (.lds.S -> .lds)
 435 # ---------------------------------------------------------------------------
 436 quiet_cmd_cpp_lds_S = LDS     $@
 437       cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
 438                              -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
 439
 440 $(obj)/%.lds: $(src)/%.lds.S FORCE
 441         $(call if_changed_dep,cpp_lds_S)
 442
 443 # ASN.1 grammar
 444 # ---------------------------------------------------------------------------
 445 quiet_cmd_asn1_compiler = ASN.1   $@
 446       cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
 447                                 $(subst .h,.c,$@) $(subst .c,.h,$@)
 448
 449 .PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
 450
 451 $(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 452         $(call cmd,asn1_compiler)
 453
 454 # Build the compiled-in targets
 455 # ---------------------------------------------------------------------------
 456
 457 # To build objects in subdirs, we need to descend into the directories
 458 $(sort $(subdir-obj-y)): $(subdir-ym) ;
 459
 460 #
 461 # Rule to compile a set of .o files into one .o file
 462 #
 463 ifdef builtin-target
 464
 465 ifdef CONFIG_THIN_ARCHIVES
 466   cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
 467   cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
 468   quiet_cmd_link_o_target = AR      $@
 469 else
 470   cmd_make_builtin = $(LD) $(ld_flags) -r -o
 471   cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
 472   quiet_cmd_link_o_target = LD      $@
 473 endif
 474
 475 # If the list of objects to link is empty, just create an empty built-in.o
 476 cmd_link_o_target = $(if $(strip $(obj-y)),\
 477                       $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
 478                       $(cmd_secanalysis),\
 479                       $(cmd_make_empty_builtin) $@)
 480
 481 $(builtin-target): $(obj-y) FORCE
 482         $(call if_changed,link_o_target)
 483
 484 targets += $(builtin-target)
 485 endif # builtin-target
 486
 487 #
 488 # Rule to create modules.order file
 489 #
 490 # Create commands to either record .ko file or cat modules.order from
 491 # a subdirectory
 492 modorder-cmds =                                         \
 493         $(foreach m, $(modorder),                       \
 494                 $(if $(filter %/modules.order, $m),     \
 495                         cat $m;, echo kernel/$m;))
 496
 497 $(modorder-target): $(subdir-ym) FORCE
 498         $(Q)(cat /dev/null; $(modorder-cmds)) > $@
 499
 500 #
 501 # Rule to compile a set of .o files into one .a file
 502 #
 503 ifdef lib-target
 504 quiet_cmd_link_l_target = AR      $@
 505
 506 ifdef CONFIG_THIN_ARCHIVES
 507   cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
 508 else
 509   cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
 510 endif
 511
 512 $(lib-target): $(lib-y) FORCE
 513         $(call if_changed,link_l_target)
 514
 515 targets += $(lib-target)
 516
 517 dummy-object = $(obj)/.lib_exports.o
 518 ksyms-lds = $(dot-target).lds
 519 ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
 520 ref_prefix = EXTERN(_
 521 else
 522 ref_prefix = EXTERN(
 523 endif
 524
 525 quiet_cmd_export_list = EXPORTS $@
 526 cmd_export_list = $(OBJDUMP) -h $< | \
 527         sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
 528         rm -f $(dummy-object);\
 529         echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
 530         $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
 531         rm $(dummy-object) $(ksyms-lds)
 532
 533 $(obj)/lib-ksyms.o: $(lib-target) FORCE
 534         $(call if_changed,export_list)
 535
 536 targets += $(obj)/lib-ksyms.o
 537
 538 endif
 539
 540 #
 541 # Rule to link composite objects
 542 #
 543 #  Composite objects are specified in kbuild makefile as follows:
 544 #    <composite-object>-objs := <list of .o files>
 545 #  or
 546 #    <composite-object>-y    := <list of .o files>
 547 #  or
 548 #    <composite-object>-m    := <list of .o files>
 549 #  The -m syntax only works if <composite object> is a module
 550 link_multi_deps =                     \
 551 $(filter $(addprefix $(obj)/,         \
 552 $($(subst $(obj)/,,$(@:.o=-objs)))    \
 553 $($(subst $(obj)/,,$(@:.o=-y)))       \
 554 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
 555
 556 cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
 557
 558 ifdef CONFIG_THIN_ARCHIVES
 559   quiet_cmd_link_multi-y = AR      $@
 560   cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
 561 else
 562   quiet_cmd_link_multi-y = LD      $@
 563   cmd_link_multi-y = $(cmd_link_multi-link)
 564 endif
 565
 566 quiet_cmd_link_multi-m = LD [M]  $@
 567 cmd_link_multi-m = $(cmd_link_multi-link)
 568
 569 $(multi-used-y): FORCE
 570         $(call if_changed,link_multi-y)
 571 $(call multi_depend, $(multi-used-y), .o, -objs -y)
 572
 573 $(multi-used-m): FORCE
 574         $(call if_changed,link_multi-m)
 575         @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
 576            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 577 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
 578
 579 targets += $(multi-used-y) $(multi-used-m)
 580
 581
 582 # Descending
 583 # ---------------------------------------------------------------------------
 584
 585 PHONY += $(subdir-ym)
 586 $(subdir-ym):
 587         $(Q)$(MAKE) $(build)=$@
 588
 589 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 590 # ---------------------------------------------------------------------------
 591
 592 PHONY += FORCE
 593
 594 FORCE:
 595
 596 # Read all saved command lines and dependencies for the $(targets) we
 597 # may be building above, using $(if_changed{,_dep}). As an
 598 # optimization, we don't need to read them if the target does not
 599 # exist, we will rebuild anyway in that case.
 600
 601 targets := $(wildcard $(sort $(targets)))
 602 cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
 603
 604 ifneq ($(cmd_files),)
 605   include $(cmd_files)
 606 endif
 607
 608 # Declare the contents of the .PHONY variable as phony.  We keep that
 609 # information in a variable se we can use it in if_changed and friends.
 610
 611 .PHONY: $(PHONY)