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 := 19always-y := 20always-m := 21targets := 22subdir-y := 23subdir-m := 24EXTRA_AFLAGS := 25EXTRA_CFLAGS := 26EXTRA_CPPFLAGS := 27EXTRA_LDFLAGS := 28asflags-y := 29ccflags-y := 30cppflags-y := 31ldflags-y := 32 33subdir-asflags-y := 34subdir-ccflags-y := 35 36# Read auto.conf if it exists, otherwise ignore 37-include include/config/auto.conf 38 39include scripts/Kbuild.include 40 41# The filename Kbuild has precedence over Makefile 42kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 43kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) 44include $(kbuild-file) 45 46include scripts/Makefile.lib 47 48# Do not include hostprogs rules unless needed. 49# $(sort ...) is used here to remove duplicated words and excessive spaces. 50hostprogs := $(sort $(hostprogs)) 51ifneq ($(hostprogs),) 52include scripts/Makefile.host 53endif 54 55# Do not include userprogs rules unless needed. 56# $(sort ...) is used here to remove duplicated words and excessive spaces. 57userprogs := $(sort $(userprogs)) 58ifneq ($(userprogs),) 59include scripts/Makefile.userprogs 60endif 61 62ifndef obj 63$(warning kbuild: Makefile.build is included improperly) 64endif 65 66ifeq ($(need-modorder),) 67ifneq ($(obj-m),) 68$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 69$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 70endif 71endif 72 73# =========================================================================== 74 75# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...) 76subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y))) 77subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) 78 79targets-for-builtin := $(extra-y) 80 81ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 82targets-for-builtin += $(obj)/lib.a 83endif 84 85ifdef need-builtin 86targets-for-builtin += $(obj)/built-in.a 87endif 88 89targets-for-modules := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m))) 90 91ifdef need-modorder 92targets-for-modules += $(obj)/modules.order 93endif 94 95targets += $(targets-for-builtin) $(targets-for-modules) 96 97# Linus' kernel sanity checking tool 98ifeq ($(KBUILD_CHECKSRC),1) 99 quiet_cmd_checksrc = CHECK $< 100 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 101else ifeq ($(KBUILD_CHECKSRC),2) 102 quiet_cmd_force_checksrc = CHECK $< 103 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 104endif 105 106ifneq ($(KBUILD_EXTRA_WARN),) 107 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 108endif 109 110# Compile C sources (.c) 111# --------------------------------------------------------------------------- 112 113quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 114 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) -fverbose-asm -S -o $@ $< 115 116$(obj)/%.s: $(src)/%.c FORCE 117 $(call if_changed_dep,cc_s_c) 118 119quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 120cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 121 122$(obj)/%.i: $(src)/%.c FORCE 123 $(call if_changed_dep,cpp_i_c) 124 125# These mirror gensymtypes_S and co below, keep them in synch. 126cmd_gensymtypes_c = \ 127 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 128 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 129 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 130 $(if $(KBUILD_PRESERVE),-p) \ 131 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 132 133quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 134cmd_cc_symtypes_c = \ 135 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ 136 test -s $@ || rm -f $@ 137 138$(obj)/%.symtypes : $(src)/%.c FORCE 139 $(call cmd,cc_symtypes_c) 140 141# LLVM assembly 142# Generate .ll files from .c 143quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 144 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< 145 146$(obj)/%.ll: $(src)/%.c FORCE 147 $(call if_changed_dep,cc_ll_c) 148 149# C (.c) files 150# The C file is compiled and updated dependency information is generated. 151# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 152 153quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 154 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 155 156ifdef CONFIG_MODVERSIONS 157# When module versioning is enabled the following steps are executed: 158# o compile a <file>.o from <file>.c 159# o if <file>.o doesn't contain a __ksymtab version, i.e. does 160# not export symbols, it's done. 161# o otherwise, we calculate symbol versions using the good old 162# genksyms on the preprocessed source and postprocess them in a way 163# that they are usable as a linker script 164# o generate .tmp_<file>.o from <file>.o using the linker to 165# replace the unresolved symbols __crc_exported_symbol with 166# the actual value of the checksum generated by genksyms 167# o remove .tmp_<file>.o to <file>.o 168 169cmd_modversions_c = \ 170 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 171 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 172 > $(@D)/.tmp_$(@F:.o=.ver); \ 173 \ 174 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 175 -T $(@D)/.tmp_$(@F:.o=.ver); \ 176 mv -f $(@D)/.tmp_$(@F) $@; \ 177 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 178 fi 179endif 180 181ifdef CONFIG_FTRACE_MCOUNT_RECORD 182ifndef CC_USING_RECORD_MCOUNT 183# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 184ifdef BUILD_C_RECORDMCOUNT 185ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 186 RECORDMCOUNT_FLAGS = -w 187endif 188# Due to recursion, we must skip empty.o. 189# The empty.o file is created in the make process in order to determine 190# the target endianness and word size. It is made before all other C 191# files, including recordmcount. 192sub_cmd_record_mcount = \ 193 if [ $(@) != "scripts/mod/empty.o" ]; then \ 194 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 195 fi; 196recordmcount_source := $(srctree)/scripts/recordmcount.c \ 197 $(srctree)/scripts/recordmcount.h 198else 199sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 200 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 201 "$(if $(CONFIG_64BIT),64,32)" \ 202 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 203 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 204 "$(if $(part-of-module),1,0)" "$(@)"; 205recordmcount_source := $(srctree)/scripts/recordmcount.pl 206endif # BUILD_C_RECORDMCOUNT 207cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 208 $(sub_cmd_record_mcount)) 209endif # CC_USING_RECORD_MCOUNT 210endif # CONFIG_FTRACE_MCOUNT_RECORD 211 212ifdef CONFIG_STACK_VALIDATION 213ifneq ($(SKIP_STACK_VALIDATION),1) 214 215__objtool_obj := $(objtree)/tools/objtool/objtool 216 217objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check) 218 219objtool_args += $(if $(part-of-module), --module,) 220 221ifndef CONFIG_FRAME_POINTER 222objtool_args += --no-fp 223endif 224ifdef CONFIG_GCOV_KERNEL 225objtool_args += --no-unreachable 226endif 227ifdef CONFIG_RETPOLINE 228 objtool_args += --retpoline 229endif 230ifdef CONFIG_X86_SMAP 231 objtool_args += --uaccess 232endif 233 234# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 235# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 236# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 237cmd_objtool = $(if $(patsubst y%,, \ 238 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 239 $(__objtool_obj) $(objtool_args) $@) 240objtool_obj = $(if $(patsubst y%,, \ 241 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 242 $(__objtool_obj)) 243 244endif # SKIP_STACK_VALIDATION 245endif # CONFIG_STACK_VALIDATION 246 247# Rebuild all objects when objtool changes, or is enabled/disabled. 248objtool_dep = $(objtool_obj) \ 249 $(wildcard include/config/orc/unwinder.h \ 250 include/config/stack/validation.h) 251 252ifdef CONFIG_TRIM_UNUSED_KSYMS 253cmd_gen_ksymdeps = \ 254 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 255 256# List module undefined symbols 257undefined_syms = $(NM) $< | $(AWK) '$$1 == "U" { printf("%s%s", x++ ? " " : "", $$2) }'; 258endif 259 260define rule_cc_o_c 261 $(call cmd_and_fixdep,cc_o_c) 262 $(call cmd,gen_ksymdeps) 263 $(call cmd,checksrc) 264 $(call cmd,checkdoc) 265 $(call cmd,objtool) 266 $(call cmd,modversions_c) 267 $(call cmd,record_mcount) 268endef 269 270define rule_as_o_S 271 $(call cmd_and_fixdep,as_o_S) 272 $(call cmd,gen_ksymdeps) 273 $(call cmd,objtool) 274 $(call cmd,modversions_S) 275endef 276 277# Built-in and composite module parts 278$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE 279 $(call if_changed_rule,cc_o_c) 280 $(call cmd,force_checksrc) 281 282cmd_mod = { \ 283 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ 284 $(undefined_syms) echo; \ 285 } > $@ 286 287$(obj)/%.mod: $(obj)/%.o FORCE 288 $(call if_changed,mod) 289 290quiet_cmd_cc_lst_c = MKLST $@ 291 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 292 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 293 System.map $(OBJDUMP) > $@ 294 295$(obj)/%.lst: $(src)/%.c FORCE 296 $(call if_changed_dep,cc_lst_c) 297 298# Compile assembler sources (.S) 299# --------------------------------------------------------------------------- 300 301# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 302# or a file that it includes, in order to get versioned symbols. We build a 303# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 304# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 305# 306# This is convoluted. The .S file must first be preprocessed to run guards and 307# expand names, then the resulting exports must be constructed into plain 308# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 309# to make the genksyms input. 310# 311# These mirror gensymtypes_c and co above, keep them in synch. 312cmd_gensymtypes_S = \ 313 { echo "\#include <linux/kernel.h>" ; \ 314 echo "\#include <asm/asm-prototypes.h>" ; \ 315 $(CPP) $(a_flags) $< | \ 316 grep "\<___EXPORT_SYMBOL\>" | \ 317 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 318 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 319 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 320 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 321 $(if $(KBUILD_PRESERVE),-p) \ 322 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 323 324quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 325cmd_cc_symtypes_S = \ 326 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 327 test -s $@ || rm -f $@ 328 329$(obj)/%.symtypes : $(src)/%.S FORCE 330 $(call cmd,cc_symtypes_S) 331 332 333quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 334cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 335 336$(obj)/%.s: $(src)/%.S FORCE 337 $(call if_changed_dep,cpp_s_S) 338 339quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 340 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 341 342ifdef CONFIG_ASM_MODVERSIONS 343 344# versioning matches the C process described above, with difference that 345# we parse asm-prototypes.h C header to get function definitions. 346 347cmd_modversions_S = \ 348 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 349 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 350 > $(@D)/.tmp_$(@F:.o=.ver); \ 351 \ 352 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 353 -T $(@D)/.tmp_$(@F:.o=.ver); \ 354 mv -f $(@D)/.tmp_$(@F) $@; \ 355 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 356 fi 357endif 358 359$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE 360 $(call if_changed_rule,as_o_S) 361 362targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 363targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 364targets += $(lib-y) $(always-y) $(MAKECMDGOALS) 365 366# Linker scripts preprocessor (.lds.S -> .lds) 367# --------------------------------------------------------------------------- 368quiet_cmd_cpp_lds_S = LDS $@ 369 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 370 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 371 372$(obj)/%.lds: $(src)/%.lds.S FORCE 373 $(call if_changed_dep,cpp_lds_S) 374 375# ASN.1 grammar 376# --------------------------------------------------------------------------- 377quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 378 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 379 $(basename $@).c $(basename $@).h 380 381$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 382 $(call cmd,asn1_compiler) 383 384# Build the compiled-in targets 385# --------------------------------------------------------------------------- 386 387# To build objects in subdirs, we need to descend into the directories 388$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 389$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 390 391# 392# Rule to compile a set of .o files into one .a file (without symbol table) 393# 394 395quiet_cmd_ar_builtin = AR $@ 396 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) 397 398$(obj)/built-in.a: $(real-obj-y) FORCE 399 $(call if_changed,ar_builtin) 400 401# 402# Rule to create modules.order file 403# 404# Create commands to either record .ko file or cat modules.order from 405# a subdirectory 406# Add $(obj-m) as the prerequisite to avoid updating the timestamp of 407# modules.order unless contained modules are updated. 408 409cmd_modules_order = { $(foreach m, $(real-prereqs), \ 410 $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \ 411 | $(AWK) '!x[$$0]++' - > $@ 412 413$(obj)/modules.order: $(obj-m) FORCE 414 $(call if_changed,modules_order) 415 416# 417# Rule to compile a set of .o files into one .a file (with symbol table) 418# 419$(obj)/lib.a: $(lib-y) FORCE 420 $(call if_changed,ar) 421 422# NOTE: 423# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object 424# module is turned into a multi object module, $^ will contain header file 425# dependencies recorded in the .*.cmd file. 426quiet_cmd_link_multi-m = LD [M] $@ 427 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) 428 429$(multi-used-m): FORCE 430 $(call if_changed,link_multi-m) 431$(call multi_depend, $(multi-used-m), .o, -objs -y -m) 432 433targets += $(multi-used-m) 434targets := $(filter-out $(PHONY), $(targets)) 435 436# Add intermediate targets: 437# When building objects with specific suffix patterns, add intermediate 438# targets that the final targets are derived from. 439intermediate_targets = $(foreach sfx, $(2), \ 440 $(patsubst %$(strip $(1)),%$(sfx), \ 441 $(filter %$(strip $(1)), $(targets)))) 442# %.asn1.o <- %.asn1.[ch] <- %.asn1 443# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 444# %.lex.o <- %.lex.c <- %.l 445# %.tab.o <- %.tab.[ch] <- %.y 446targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 447 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 448 $(call intermediate_targets, .lex.o, .lex.c) \ 449 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 450 451# Build 452# --------------------------------------------------------------------------- 453 454ifdef single-build 455 456KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS)) 457 458curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ 459 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) 460 461# Handle single targets without any rule: show "Nothing to be done for ..." or 462# "No rule to make target ..." depending on whether the target exists. 463unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ 464 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS))) 465 466single-subdirs := $(foreach d, $(subdir-ym), \ 467 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d))) 468 469__build: $(curdir-single) $(single-subdirs) 470ifneq ($(unknown-single),) 471 $(Q)$(MAKE) -f /dev/null $(unknown-single) 472endif 473 @: 474 475ifeq ($(curdir-single),) 476# Nothing to do in this directory. Do not include any .*.cmd file for speed-up 477targets := 478else 479targets += $(curdir-single) 480endif 481 482else 483 484__build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 485 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 486 $(subdir-ym) $(always-y) 487 @: 488 489endif 490 491# Descending 492# --------------------------------------------------------------------------- 493 494PHONY += $(subdir-ym) 495$(subdir-ym): 496 $(Q)$(MAKE) $(build)=$@ \ 497 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ 498 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 499 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) 500 501# Add FORCE to the prequisites of a target to force it to be always rebuilt. 502# --------------------------------------------------------------------------- 503 504PHONY += FORCE 505 506FORCE: 507 508# Read all saved command lines and dependencies for the $(targets) we 509# may be building above, using $(if_changed{,_dep}). As an 510# optimization, we don't need to read them if the target does not 511# exist, we will rebuild anyway in that case. 512 513existing-targets := $(wildcard $(sort $(targets))) 514 515-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 516 517# Create directories for object files if they do not exist 518obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 519# If targets exist, their directories apparently exist. Skip mkdir. 520existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 521obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 522ifneq ($(obj-dirs),) 523$(shell mkdir -p $(obj-dirs)) 524endif 525 526.PHONY: $(PHONY) 527