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)) $(DISABLE_LTO) -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 255endif 256 257define rule_cc_o_c 258 $(call cmd_and_fixdep,cc_o_c) 259 $(call cmd,gen_ksymdeps) 260 $(call cmd,checksrc) 261 $(call cmd,checkdoc) 262 $(call cmd,objtool) 263 $(call cmd,modversions_c) 264 $(call cmd,record_mcount) 265endef 266 267define rule_as_o_S 268 $(call cmd_and_fixdep,as_o_S) 269 $(call cmd,gen_ksymdeps) 270 $(call cmd,objtool) 271 $(call cmd,modversions_S) 272endef 273 274# List module undefined symbols (or empty line if not enabled) 275ifdef CONFIG_TRIM_UNUSED_KSYMS 276cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo 277else 278cmd_undef_syms = echo 279endif 280 281# Built-in and composite module parts 282$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE 283 $(call if_changed_rule,cc_o_c) 284 $(call cmd,force_checksrc) 285 286cmd_mod = { \ 287 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ 288 $(cmd_undef_syms); \ 289 } > $@ 290 291$(obj)/%.mod: $(obj)/%.o FORCE 292 $(call if_changed,mod) 293 294quiet_cmd_cc_lst_c = MKLST $@ 295 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 296 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 297 System.map $(OBJDUMP) > $@ 298 299$(obj)/%.lst: $(src)/%.c FORCE 300 $(call if_changed_dep,cc_lst_c) 301 302# Compile assembler sources (.S) 303# --------------------------------------------------------------------------- 304 305# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 306# or a file that it includes, in order to get versioned symbols. We build a 307# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 308# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 309# 310# This is convoluted. The .S file must first be preprocessed to run guards and 311# expand names, then the resulting exports must be constructed into plain 312# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 313# to make the genksyms input. 314# 315# These mirror gensymtypes_c and co above, keep them in synch. 316cmd_gensymtypes_S = \ 317 { echo "\#include <linux/kernel.h>" ; \ 318 echo "\#include <asm/asm-prototypes.h>" ; \ 319 $(CPP) $(a_flags) $< | \ 320 grep "\<___EXPORT_SYMBOL\>" | \ 321 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 322 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 323 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 324 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 325 $(if $(KBUILD_PRESERVE),-p) \ 326 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 327 328quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 329cmd_cc_symtypes_S = \ 330 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 331 test -s $@ || rm -f $@ 332 333$(obj)/%.symtypes : $(src)/%.S FORCE 334 $(call cmd,cc_symtypes_S) 335 336 337quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 338cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 339 340$(obj)/%.s: $(src)/%.S FORCE 341 $(call if_changed_dep,cpp_s_S) 342 343quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 344 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 345 346ifdef CONFIG_ASM_MODVERSIONS 347 348# versioning matches the C process described above, with difference that 349# we parse asm-prototypes.h C header to get function definitions. 350 351cmd_modversions_S = \ 352 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 353 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 354 > $(@D)/.tmp_$(@F:.o=.ver); \ 355 \ 356 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 357 -T $(@D)/.tmp_$(@F:.o=.ver); \ 358 mv -f $(@D)/.tmp_$(@F) $@; \ 359 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 360 fi 361endif 362 363$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE 364 $(call if_changed_rule,as_o_S) 365 366targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 367targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 368targets += $(lib-y) $(always-y) $(MAKECMDGOALS) 369 370# Linker scripts preprocessor (.lds.S -> .lds) 371# --------------------------------------------------------------------------- 372quiet_cmd_cpp_lds_S = LDS $@ 373 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 374 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 375 376$(obj)/%.lds: $(src)/%.lds.S FORCE 377 $(call if_changed_dep,cpp_lds_S) 378 379# ASN.1 grammar 380# --------------------------------------------------------------------------- 381quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 382 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 383 $(basename $@).c $(basename $@).h 384 385$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 386 $(call cmd,asn1_compiler) 387 388# Build the compiled-in targets 389# --------------------------------------------------------------------------- 390 391# To build objects in subdirs, we need to descend into the directories 392$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 393$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 394 395# 396# Rule to compile a set of .o files into one .a file (without symbol table) 397# 398 399quiet_cmd_ar_builtin = AR $@ 400 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) 401 402$(obj)/built-in.a: $(real-obj-y) FORCE 403 $(call if_changed,ar_builtin) 404 405# 406# Rule to create modules.order file 407# 408# Create commands to either record .ko file or cat modules.order from 409# a subdirectory 410# Add $(obj-m) as the prerequisite to avoid updating the timestamp of 411# modules.order unless contained modules are updated. 412 413cmd_modules_order = { $(foreach m, $(real-prereqs), \ 414 $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \ 415 | $(AWK) '!x[$$0]++' - > $@ 416 417$(obj)/modules.order: $(obj-m) FORCE 418 $(call if_changed,modules_order) 419 420# 421# Rule to compile a set of .o files into one .a file (with symbol table) 422# 423$(obj)/lib.a: $(lib-y) FORCE 424 $(call if_changed,ar) 425 426# NOTE: 427# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object 428# module is turned into a multi object module, $^ will contain header file 429# dependencies recorded in the .*.cmd file. 430quiet_cmd_link_multi-m = LD [M] $@ 431 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) 432 433$(multi-used-m): FORCE 434 $(call if_changed,link_multi-m) 435$(call multi_depend, $(multi-used-m), .o, -objs -y -m) 436 437targets += $(multi-used-m) 438targets := $(filter-out $(PHONY), $(targets)) 439 440# Add intermediate targets: 441# When building objects with specific suffix patterns, add intermediate 442# targets that the final targets are derived from. 443intermediate_targets = $(foreach sfx, $(2), \ 444 $(patsubst %$(strip $(1)),%$(sfx), \ 445 $(filter %$(strip $(1)), $(targets)))) 446# %.asn1.o <- %.asn1.[ch] <- %.asn1 447# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 448# %.lex.o <- %.lex.c <- %.l 449# %.tab.o <- %.tab.[ch] <- %.y 450targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 451 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 452 $(call intermediate_targets, .lex.o, .lex.c) \ 453 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 454 455# Build 456# --------------------------------------------------------------------------- 457 458ifdef single-build 459 460KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS)) 461 462curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ 463 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) 464 465# Handle single targets without any rule: show "Nothing to be done for ..." or 466# "No rule to make target ..." depending on whether the target exists. 467unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ 468 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS))) 469 470single-subdirs := $(foreach d, $(subdir-ym), \ 471 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d))) 472 473__build: $(curdir-single) $(single-subdirs) 474ifneq ($(unknown-single),) 475 $(Q)$(MAKE) -f /dev/null $(unknown-single) 476endif 477 @: 478 479ifeq ($(curdir-single),) 480# Nothing to do in this directory. Do not include any .*.cmd file for speed-up 481targets := 482else 483targets += $(curdir-single) 484endif 485 486else 487 488__build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 489 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 490 $(subdir-ym) $(always-y) 491 @: 492 493endif 494 495# Descending 496# --------------------------------------------------------------------------- 497 498PHONY += $(subdir-ym) 499$(subdir-ym): 500 $(Q)$(MAKE) $(build)=$@ \ 501 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ 502 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 503 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) 504 505# Add FORCE to the prequisites of a target to force it to be always rebuilt. 506# --------------------------------------------------------------------------- 507 508PHONY += FORCE 509 510FORCE: 511 512# Read all saved command lines and dependencies for the $(targets) we 513# may be building above, using $(if_changed{,_dep}). As an 514# optimization, we don't need to read them if the target does not 515# exist, we will rebuild anyway in that case. 516 517existing-targets := $(wildcard $(sort $(targets))) 518 519-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 520 521# Create directories for object files if they do not exist 522obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 523# If targets exist, their directories apparently exist. Skip mkdir. 524existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 525obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 526ifneq ($(obj-dirs),) 527$(shell mkdir -p $(obj-dirs)) 528endif 529 530.PHONY: $(PHONY) 531