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 ifdef CONFIG_LTO_CLANG
 214 # Generate .o.symversions files for each .o with exported symbols, and link these
 215 # to the kernel and/or modules at the end.
 216 cmd_modversions_c =                                                             \
 217         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) >/dev/null 2>/dev/null; then          \
 218                 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then     \
 219                         $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
 220                             > $(@D)/$(@F).symversions;                          \
 221                 fi;                                                             \
 222         else                                                                    \
 223                 if $(LLVM_DIS) -o=- $(@D)/.tmp_$(@F) | grep -q __ksymtab; then  \
 224                         $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
 225                             > $(@D)/$(@F).symversions;                          \
 226                 fi;                                                             \
 227         fi;                                                                     \
 228         mv -f $(@D)/.tmp_$(@F) $@;
 229 else
 230 cmd_modversions_c =                                                             \
 231         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 232                 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 233                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 234                                                                                 \
 235                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
 236                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 237                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 238         else                                                                    \
 239                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 240         fi;
 241 endif
 242 endif
 243
 244 ifdef CONFIG_FTRACE_MCOUNT_RECORD
 245 ifdef BUILD_C_RECORDMCOUNT
 246 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
 247   RECORDMCOUNT_FLAGS = -w
 248 endif
 249
 250 ifdef CONFIG_LTO_CLANG
 251 # With LTO, we postpone running recordmcount until after the LTO link step, so
 252 # let's export the parameters for the link script.
 253 export RECORDMCOUNT_FLAGS
 254 else
 255 # Due to recursion, we must skip empty.o.
 256 # The empty.o file is created in the make process in order to determine
 257 # the target endianness and word size. It is made before all other C
 258 # files, including recordmcount.
 259 sub_cmd_record_mcount =                                 \
 260         if [ $(@) != "scripts/mod/empty.o" ]; then      \
 261                 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";   \
 262         fi;
 263 endif
 264
 265 recordmcount_source := $(srctree)/scripts/recordmcount.c \
 266                     $(srctree)/scripts/recordmcount.h
 267 else # !BUILD_C_RECORDMCOUNT
 268 sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
 269         "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
 270         "$(if $(CONFIG_64BIT),64,32)" \
 271         "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
 272         "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
 273         "$(if $(part-of-module),1,0)" "$(@)";
 274
 275 recordmcount_source := $(srctree)/scripts/recordmcount.pl
 276 endif # BUILD_C_RECORDMCOUNT
 277
 278 ifndef CONFIG_LTO_CLANG
 279 cmd_record_mcount =                                             \
 280         if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =   \
 281              "$(CC_FLAGS_FTRACE)" ]; then                       \
 282                 $(sub_cmd_record_mcount)                        \
 283         fi;
 284 endif
 285 endif # CONFIG_FTRACE_MCOUNT_RECORD
 286
 287 ifdef CONFIG_STACK_VALIDATION
 288 ifneq ($(SKIP_STACK_VALIDATION),1)
 289
 290 __objtool_obj := $(objtree)/tools/objtool/objtool
 291
 292 objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
 293
 294 objtool_args += $(if $(part-of-module), --module,)
 295
 296 ifndef CONFIG_FRAME_POINTER
 297 objtool_args += --no-fp
 298 endif
 299 ifdef CONFIG_GCOV_KERNEL
 300 objtool_args += --no-unreachable
 301 else
 302 objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
 303 endif
 304 ifdef CONFIG_RETPOLINE
 305   objtool_args += --retpoline
 306 endif
 307
 308
 309 ifdef CONFIG_MODVERSIONS
 310 objtool_o = $(@D)/.tmp_$(@F)
 311 else
 312 objtool_o = $(@)
 313 endif
 314
 315 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
 316 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
 317 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
 318 cmd_objtool = $(if $(patsubst y%,, \
 319         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 320         $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
 321 objtool_obj = $(if $(patsubst y%,, \
 322         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
 323         $(__objtool_obj))
 324
 325 endif # SKIP_STACK_VALIDATION
 326 endif # CONFIG_STACK_VALIDATION
 327
 328 # Rebuild all objects when objtool changes, or is enabled/disabled.
 329 objtool_dep = $(objtool_obj)                                    \
 330               $(wildcard include/config/orc/unwinder.h          \
 331                          include/config/stack/validation.h)
 332
 333 define rule_cc_o_c
 334         $(call echo-cmd,checksrc) $(cmd_checksrc)                         \
 335         $(call cmd_and_fixdep,cc_o_c)                                     \
 336         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 337         $(cmd_modversions_c)                                              \
 338         $(call echo-cmd,record_mcount) $(cmd_record_mcount)
 339 endef
 340
 341 define rule_as_o_S
 342         $(call cmd_and_fixdep,as_o_S)                                     \
 343         $(call echo-cmd,objtool) $(cmd_objtool)                           \
 344         $(cmd_modversions_S)
 345 endef
 346
 347 # List module undefined symbols (or empty line if not enabled)
 348 ifdef CONFIG_TRIM_UNUSED_KSYMS
 349 cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
 350 else
 351 cmd_undef_syms = echo
 352 endif
 353
 354 # Built-in and composite module parts
 355 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 356         $(call cmd,force_checksrc)
 357         $(call if_changed_rule,cc_o_c)
 358
 359 # Single-part modules are special since we need to mark them in $(MODVERDIR)
 360
 361 $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
 362         $(call cmd,force_checksrc)
 363         $(call if_changed_rule,cc_o_c)
 364         @{ echo $(@:.o=.ko); echo $@; \
 365            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 366
 367 quiet_cmd_cc_lst_c = MKLST   $@
 368       cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
 369                      $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
 370                                      System.map $(OBJDUMP) > $@
 371
 372 $(obj)/%.lst: $(src)/%.c FORCE
 373         $(call if_changed_dep,cc_lst_c)
 374
 375 # Compile assembler sources (.S)
 376 # ---------------------------------------------------------------------------
 377
 378 modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
 379
 380 $(real-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 381 $(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 382
 383 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
 384 # or a file that it includes, in order to get versioned symbols. We build a
 385 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
 386 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
 387 #
 388 # This is convoluted. The .S file must first be preprocessed to run guards and
 389 # expand names, then the resulting exports must be constructed into plain
 390 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
 391 # to make the genksyms input.
 392 #
 393 # These mirror gensymtypes_c and co above, keep them in synch.
 394 cmd_gensymtypes_S =                                                         \
 395     (echo "\#include <linux/kernel.h>" ;                                    \
 396      echo "\#include <asm/asm-prototypes.h>" ;                              \
 397     $(CPP) $(a_flags) $< |                                                  \
 398      grep "\<___EXPORT_SYMBOL\>" |                                          \
 399      sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
 400     $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
 401     $(GENKSYMS) $(if $(1), -T $(2))                                         \
 402      $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
 403      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
 404      $(if $(KBUILD_PRESERVE),-p)                                            \
 405      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
 406
 407 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
 408 cmd_cc_symtypes_S =                                                         \
 409     set -e;                                                                 \
 410     $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
 411     test -s $@ || rm -f $@
 412
 413 $(obj)/%.symtypes : $(src)/%.S FORCE
 414         $(call cmd,cc_symtypes_S)
 415
 416
 417 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
 418 cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
 419
 420 $(obj)/%.s: $(src)/%.S FORCE
 421         $(call if_changed_dep,cpp_s_S)
 422
 423 quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
 424
 425 ifndef CONFIG_MODVERSIONS
 426 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 427
 428 else
 429
 430 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
 431
 432 ifeq ($(ASM_PROTOTYPES),)
 433 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 434
 435 else
 436
 437 # versioning matches the C process described above, with difference that
 438 # we parse asm-prototypes.h C header to get function definitions.
 439
 440 cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
 441
 442 cmd_modversions_S =                                                             \
 443         if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
 444                 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
 445                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
 446                                                                                 \
 447                 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F)                      \
 448                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
 449                 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);                \
 450         else                                                                    \
 451                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
 452         fi;
 453 endif
 454 endif
 455
 456 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
 457         $(call if_changed_rule,as_o_S)
 458
 459 targets += $(real-objs-y) $(real-objs-m) $(lib-y)
 460 targets += $(extra-y) $(MAKECMDGOALS) $(always)
 461
 462 # Linker scripts preprocessor (.lds.S -> .lds)
 463 # ---------------------------------------------------------------------------
 464 quiet_cmd_cpp_lds_S = LDS     $@
 465       cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
 466                              -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
 467
 468 $(obj)/%.lds: $(src)/%.lds.S FORCE
 469         $(call if_changed_dep,cpp_lds_S)
 470
 471 # ASN.1 grammar
 472 # ---------------------------------------------------------------------------
 473 quiet_cmd_asn1_compiler = ASN.1   $@
 474       cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
 475                                 $(subst .h,.c,$@) $(subst .c,.h,$@)
 476
 477 .PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
 478
 479 $(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 480         $(call cmd,asn1_compiler)
 481
 482 # Build the compiled-in targets
 483 # ---------------------------------------------------------------------------
 484
 485 # To build objects in subdirs, we need to descend into the directories
 486 $(sort $(subdir-obj-y)): $(subdir-ym) ;
 487
 488 #
 489 # Rule to compile a set of .o files into one .o file
 490 #
 491 ifdef builtin-target
 492
 493 ifdef CONFIG_LTO_CLANG
 494   ifdef CONFIG_MODVERSIONS
 495     # combine symversions for later processing
 496     update_lto_symversions =                            \
 497         rm -f $@.symversions;                           \
 498         for i in $(filter-out FORCE,$^); do             \
 499                 if [ -f $$i.symversions ]; then         \
 500                         cat $$i.symversions             \
 501                                 >> $@.symversions;      \
 502                 fi;                                     \
 503         done;
 504   endif
 505   # rebuild the symbol table with llvm-ar to include IR files
 506   update_lto_symtable = ;                               \
 507         mv -f $@ $@.tmp;                                \
 508         $(LLVM_AR) rcsT$(KBUILD_ARFLAGS) $@             \
 509                 $$($(AR) t $@.tmp);                     \
 510         rm -f $@.tmp
 511 endif
 512
 513 ifdef CONFIG_THIN_ARCHIVES
 514   cmd_make_builtin = $(update_lto_symversions)  \
 515         rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
 516   cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
 517   quiet_cmd_link_o_target = AR      $@
 518 else
 519   cmd_make_builtin = $(LD) $(ld_flags) -r -o
 520   cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
 521   quiet_cmd_link_o_target = LD      $@
 522 endif
 523
 524 # If the list of objects to link is empty, just create an empty built-in.o
 525 cmd_link_o_target = $(if $(strip $(obj-y)),\
 526                       $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
 527                       $(cmd_secanalysis),\
 528                       $(cmd_make_empty_builtin) $@)
 529
 530 $(builtin-target): $(obj-y) FORCE
 531         $(call if_changed,link_o_target)
 532
 533 targets += $(builtin-target)
 534 endif # builtin-target
 535
 536 #
 537 # Rule to create modules.order file
 538 #
 539 # Create commands to either record .ko file or cat modules.order from
 540 # a subdirectory
 541 modorder-cmds =                                         \
 542         $(foreach m, $(modorder),                       \
 543                 $(if $(filter %/modules.order, $m),     \
 544                         cat $m;, echo kernel/$m;))
 545
 546 $(modorder-target): $(subdir-ym) FORCE
 547         $(Q)(cat /dev/null; $(modorder-cmds)) > $@
 548
 549 #
 550 # Rule to compile a set of .o files into one .a file
 551 #
 552 ifdef lib-target
 553 quiet_cmd_link_l_target = AR      $@
 554
 555 ifdef CONFIG_THIN_ARCHIVES
 556   cmd_link_l_target =                                   \
 557         $(update_lto_symversions)                       \
 558         rm -f $@;                                       \
 559         $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)        \
 560         $(update_lto_symtable)
 561 else
 562   cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
 563 endif
 564
 565 $(lib-target): $(lib-y) FORCE
 566         $(call if_changed,link_l_target)
 567
 568 targets += $(lib-target)
 569
 570 dummy-object = $(obj)/.lib_exports.o
 571 ksyms-lds = $(dot-target).lds
 572 ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
 573 ref_prefix = EXTERN(_
 574 else
 575 ref_prefix = EXTERN(
 576 endif
 577
 578 filter_export_list = sed -ne '/___ksymtab/s/.*+\([^ "]*\).*/$(ref_prefix)\1)/p'
 579 link_export_list = rm -f $(dummy-object);\
 580         echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
 581         $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
 582         rm $(dummy-object) $(ksyms-lds)
 583
 584 quiet_cmd_export_list = EXPORTS $@
 585
 586 ifdef CONFIG_LTO_CLANG
 587 # objdump doesn't understand IR files and llvm-dis doesn't support archives,
 588 # so we'll walk through each file in the archive separately
 589 cmd_export_list =                                       \
 590         rm -f $(ksyms-lds);                             \
 591         for o in $$($(AR) t $<); do                     \
 592                 if $(OBJDUMP) -h $$o >/dev/null 2>/dev/null; then \
 593                         $(OBJDUMP) -h $$o |             \
 594                                 $(filter_export_list)   \
 595                                 >>$(ksyms-lds);         \
 596                 else                                    \
 597                         $(LLVM_DIS) -o=- $$o |          \
 598                                 $(filter_export_list)   \
 599                                 >>$(ksyms-lds);         \
 600                 fi;                                     \
 601         done;                                           \
 602         $(link_export_list)
 603 else
 604 cmd_export_list = $(OBJDUMP) -h $< | $(filter_export_list) >$(ksyms-lds); \
 605         $(link_export_list)
 606 endif
 607
 608 $(obj)/lib-ksyms.o: $(lib-target) FORCE
 609         $(call if_changed,export_list)
 610
 611 targets += $(obj)/lib-ksyms.o
 612
 613 endif
 614
 615 #
 616 # Rule to link composite objects
 617 #
 618 #  Composite objects are specified in kbuild makefile as follows:
 619 #    <composite-object>-objs := <list of .o files>
 620 #  or
 621 #    <composite-object>-y    := <list of .o files>
 622 #  or
 623 #    <composite-object>-m    := <list of .o files>
 624 #  The -m syntax only works if <composite object> is a module
 625 link_multi_deps =                     \
 626 $(filter $(addprefix $(obj)/,         \
 627 $($(subst $(obj)/,,$(@:.o=-objs)))    \
 628 $($(subst $(obj)/,,$(@:.o=-y)))       \
 629 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
 630
 631 cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
 632
 633 ifdef CONFIG_THIN_ARCHIVES
 634   quiet_cmd_link_multi-y = AR      $@
 635   cmd_link_multi-y = $(update_lto_symversions) \
 636         rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps) \
 637         $(update_lto_symtable)
 638 else
 639   quiet_cmd_link_multi-y = LD      $@
 640   cmd_link_multi-y = $(cmd_link_multi-link)
 641 endif
 642
 643 quiet_cmd_link_multi-m = LD [M]  $@
 644
 645 ifdef CONFIG_LTO_CLANG
 646   # don't compile IR until needed
 647   cmd_link_multi-m = $(cmd_link_multi-y)
 648 else
 649   cmd_link_multi-m = $(cmd_link_multi-link)
 650 endif
 651
 652 $(multi-used-y): FORCE
 653         $(call if_changed,link_multi-y)
 654
 655 $(multi-used-m): FORCE
 656         $(call if_changed,link_multi-m)
 657         @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
 658            $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
 659
 660 $(call multi_depend, $(multi-used-y), .o, -objs -y)
 661 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
 662
 663 targets += $(multi-used-y) $(multi-used-m)
 664
 665
 666 # Descending
 667 # ---------------------------------------------------------------------------
 668
 669 PHONY += $(subdir-ym)
 670 $(subdir-ym):
 671         $(Q)$(MAKE) $(build)=$@
 672
 673 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 674 # ---------------------------------------------------------------------------
 675
 676 PHONY += FORCE
 677
 678 FORCE:
 679
 680 # Read all saved command lines and dependencies for the $(targets) we
 681 # may be building above, using $(if_changed{,_dep}). As an
 682 # optimization, we don't need to read them if the target does not
 683 # exist, we will rebuild anyway in that case.
 684
 685 targets := $(wildcard $(sort $(targets)))
 686 cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
 687
 688 ifneq ($(cmd_files),)
 689   include $(cmd_files)
 690 endif
 691
 692 # Declare the contents of the .PHONY variable as phony.  We keep that
 693 # information in a variable se we can use it in if_changed and friends.
 694
 695 .PHONY: $(PHONY)