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 $(kbuild-file) 45 46include scripts/Makefile.lib 47 48# Do not include host rules unless needed 49ifneq ($(hostprogs)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),) 50include scripts/Makefile.host 51endif 52 53ifndef obj 54$(warning kbuild: Makefile.build is included improperly) 55endif 56 57ifeq ($(need-modorder),) 58ifneq ($(obj-m),) 59$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 60$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 61endif 62endif 63 64# =========================================================================== 65 66ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 67lib-target := $(obj)/lib.a 68real-obj-y += $(obj)/lib-ksyms.o 69endif 70 71ifdef need-builtin 72builtin-target := $(obj)/built-in.a 73endif 74 75ifeq ($(CONFIG_MODULES)$(need-modorder),y1) 76modorder-target := $(obj)/modules.order 77endif 78 79mod-targets := $(patsubst %.o, %.mod, $(obj-m)) 80 81# Linus' kernel sanity checking tool 82ifeq ($(KBUILD_CHECKSRC),1) 83 quiet_cmd_checksrc = CHECK $< 84 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 85else ifeq ($(KBUILD_CHECKSRC),2) 86 quiet_cmd_force_checksrc = CHECK $< 87 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 88endif 89 90ifneq ($(KBUILD_EXTRA_WARN),) 91 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 92endif 93 94# Compile C sources (.c) 95# --------------------------------------------------------------------------- 96 97quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 98 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $< 99 100$(obj)/%.s: $(src)/%.c FORCE 101 $(call if_changed_dep,cc_s_c) 102 103quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 104cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 105 106$(obj)/%.i: $(src)/%.c FORCE 107 $(call if_changed_dep,cpp_i_c) 108 109# These mirror gensymtypes_S and co below, keep them in synch. 110cmd_gensymtypes_c = \ 111 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 112 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 113 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 114 $(if $(KBUILD_PRESERVE),-p) \ 115 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 116 117quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 118cmd_cc_symtypes_c = \ 119 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ 120 test -s $@ || rm -f $@ 121 122$(obj)/%.symtypes : $(src)/%.c FORCE 123 $(call cmd,cc_symtypes_c) 124 125# LLVM assembly 126# Generate .ll files from .c 127quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 128 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< 129 130$(obj)/%.ll: $(src)/%.c FORCE 131 $(call if_changed_dep,cc_ll_c) 132 133# C (.c) files 134# The C file is compiled and updated dependency information is generated. 135# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 136 137quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 138 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 139 140ifdef CONFIG_MODVERSIONS 141# When module versioning is enabled the following steps are executed: 142# o compile a <file>.o from <file>.c 143# o if <file>.o doesn't contain a __ksymtab version, i.e. does 144# not export symbols, it's done. 145# o otherwise, we calculate symbol versions using the good old 146# genksyms on the preprocessed source and postprocess them in a way 147# that they are usable as a linker script 148# o generate .tmp_<file>.o from <file>.o using the linker to 149# replace the unresolved symbols __crc_exported_symbol with 150# the actual value of the checksum generated by genksyms 151# o remove .tmp_<file>.o to <file>.o 152 153cmd_modversions_c = \ 154 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 155 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 156 > $(@D)/.tmp_$(@F:.o=.ver); \ 157 \ 158 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 159 -T $(@D)/.tmp_$(@F:.o=.ver); \ 160 mv -f $(@D)/.tmp_$(@F) $@; \ 161 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 162 fi 163endif 164 165ifdef CONFIG_FTRACE_MCOUNT_RECORD 166ifndef CC_USING_RECORD_MCOUNT 167# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 168ifdef BUILD_C_RECORDMCOUNT 169ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 170 RECORDMCOUNT_FLAGS = -w 171endif 172# Due to recursion, we must skip empty.o. 173# The empty.o file is created in the make process in order to determine 174# the target endianness and word size. It is made before all other C 175# files, including recordmcount. 176sub_cmd_record_mcount = \ 177 if [ $(@) != "scripts/mod/empty.o" ]; then \ 178 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 179 fi; 180recordmcount_source := $(srctree)/scripts/recordmcount.c \ 181 $(srctree)/scripts/recordmcount.h 182else 183sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 184 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 185 "$(if $(CONFIG_64BIT),64,32)" \ 186 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 187 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 188 "$(if $(part-of-module),1,0)" "$(@)"; 189recordmcount_source := $(srctree)/scripts/recordmcount.pl 190endif # BUILD_C_RECORDMCOUNT 191cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 192 $(sub_cmd_record_mcount)) 193endif # CC_USING_RECORD_MCOUNT 194endif # CONFIG_FTRACE_MCOUNT_RECORD 195 196ifdef CONFIG_STACK_VALIDATION 197ifneq ($(SKIP_STACK_VALIDATION),1) 198 199__objtool_obj := $(objtree)/tools/objtool/objtool 200 201objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check) 202 203objtool_args += $(if $(part-of-module), --module,) 204 205ifndef CONFIG_FRAME_POINTER 206objtool_args += --no-fp 207endif 208ifdef CONFIG_GCOV_KERNEL 209objtool_args += --no-unreachable 210endif 211ifdef CONFIG_RETPOLINE 212 objtool_args += --retpoline 213endif 214ifdef CONFIG_X86_SMAP 215 objtool_args += --uaccess 216endif 217 218# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 219# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 220# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 221cmd_objtool = $(if $(patsubst y%,, \ 222 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 223 $(__objtool_obj) $(objtool_args) $@) 224objtool_obj = $(if $(patsubst y%,, \ 225 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 226 $(__objtool_obj)) 227 228endif # SKIP_STACK_VALIDATION 229endif # CONFIG_STACK_VALIDATION 230 231# Rebuild all objects when objtool changes, or is enabled/disabled. 232objtool_dep = $(objtool_obj) \ 233 $(wildcard include/config/orc/unwinder.h \ 234 include/config/stack/validation.h) 235 236ifdef CONFIG_TRIM_UNUSED_KSYMS 237cmd_gen_ksymdeps = \ 238 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 239endif 240 241define rule_cc_o_c 242 $(call cmd,checksrc) 243 $(call cmd_and_fixdep,cc_o_c) 244 $(call cmd,gen_ksymdeps) 245 $(call cmd,checkdoc) 246 $(call cmd,objtool) 247 $(call cmd,modversions_c) 248 $(call cmd,record_mcount) 249endef 250 251define rule_as_o_S 252 $(call cmd_and_fixdep,as_o_S) 253 $(call cmd,gen_ksymdeps) 254 $(call cmd,objtool) 255 $(call cmd,modversions_S) 256endef 257 258# List module undefined symbols (or empty line if not enabled) 259ifdef CONFIG_TRIM_UNUSED_KSYMS 260cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo 261else 262cmd_undef_syms = echo 263endif 264 265# Built-in and composite module parts 266$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE 267 $(call cmd,force_checksrc) 268 $(call if_changed_rule,cc_o_c) 269 270cmd_mod = { \ 271 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ 272 $(cmd_undef_syms); \ 273 } > $@ 274 275$(obj)/%.mod: $(obj)/%.o FORCE 276 $(call if_changed,mod) 277 278targets += $(mod-targets) 279 280quiet_cmd_cc_lst_c = MKLST $@ 281 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 282 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 283 System.map $(OBJDUMP) > $@ 284 285$(obj)/%.lst: $(src)/%.c FORCE 286 $(call if_changed_dep,cc_lst_c) 287 288# Compile assembler sources (.S) 289# --------------------------------------------------------------------------- 290 291# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 292# or a file that it includes, in order to get versioned symbols. We build a 293# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 294# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 295# 296# This is convoluted. The .S file must first be preprocessed to run guards and 297# expand names, then the resulting exports must be constructed into plain 298# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 299# to make the genksyms input. 300# 301# These mirror gensymtypes_c and co above, keep them in synch. 302cmd_gensymtypes_S = \ 303 { echo "\#include <linux/kernel.h>" ; \ 304 echo "\#include <asm/asm-prototypes.h>" ; \ 305 $(CPP) $(a_flags) $< | \ 306 grep "\<___EXPORT_SYMBOL\>" | \ 307 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 308 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 309 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 310 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 311 $(if $(KBUILD_PRESERVE),-p) \ 312 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 313 314quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 315cmd_cc_symtypes_S = \ 316 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 317 test -s $@ || rm -f $@ 318 319$(obj)/%.symtypes : $(src)/%.S FORCE 320 $(call cmd,cc_symtypes_S) 321 322 323quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 324cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 325 326$(obj)/%.s: $(src)/%.S FORCE 327 $(call if_changed_dep,cpp_s_S) 328 329quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 330 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 331 332ifdef CONFIG_ASM_MODVERSIONS 333 334# versioning matches the C process described above, with difference that 335# we parse asm-prototypes.h C header to get function definitions. 336 337cmd_modversions_S = \ 338 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 339 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 340 > $(@D)/.tmp_$(@F:.o=.ver); \ 341 \ 342 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 343 -T $(@D)/.tmp_$(@F:.o=.ver); \ 344 mv -f $(@D)/.tmp_$(@F) $@; \ 345 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 346 fi 347endif 348 349$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE 350 $(call if_changed_rule,as_o_S) 351 352targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y) 353targets += $(extra-y) $(always-y) $(MAKECMDGOALS) 354 355# Linker scripts preprocessor (.lds.S -> .lds) 356# --------------------------------------------------------------------------- 357quiet_cmd_cpp_lds_S = LDS $@ 358 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 359 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 360 361$(obj)/%.lds: $(src)/%.lds.S FORCE 362 $(call if_changed_dep,cpp_lds_S) 363 364# ASN.1 grammar 365# --------------------------------------------------------------------------- 366quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 367 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 368 $(basename $@).c $(basename $@).h 369 370$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 371 $(call cmd,asn1_compiler) 372 373# Build the compiled-in targets 374# --------------------------------------------------------------------------- 375 376# To build objects in subdirs, we need to descend into the directories 377$(obj)/%/built-in.a: $(obj)/% ; 378 379# 380# Rule to compile a set of .o files into one .a file (without symbol table) 381# 382ifdef builtin-target 383 384quiet_cmd_ar_builtin = AR $@ 385 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) 386 387$(builtin-target): $(real-obj-y) FORCE 388 $(call if_changed,ar_builtin) 389 390targets += $(builtin-target) 391endif # builtin-target 392 393# 394# Rule to create modules.order file 395# 396# Create commands to either record .ko file or cat modules.order from 397# a subdirectory 398$(modorder-target): $(subdir-ym) FORCE 399 $(Q){ $(foreach m, $(modorder), \ 400 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \ 401 | $(AWK) '!x[$$0]++' - > $@ 402 403# 404# Rule to compile a set of .o files into one .a file (with symbol table) 405# 406ifdef lib-target 407 408$(lib-target): $(lib-y) FORCE 409 $(call if_changed,ar) 410 411targets += $(lib-target) 412 413dummy-object = $(obj)/.lib_exports.o 414ksyms-lds = $(dot-target).lds 415 416quiet_cmd_export_list = EXPORTS $@ 417cmd_export_list = $(OBJDUMP) -h $< | \ 418 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\ 419 rm -f $(dummy-object);\ 420 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\ 421 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\ 422 rm $(dummy-object) $(ksyms-lds) 423 424$(obj)/lib-ksyms.o: $(lib-target) FORCE 425 $(call if_changed,export_list) 426 427targets += $(obj)/lib-ksyms.o 428 429endif 430 431# NOTE: 432# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object 433# module is turned into a multi object module, $^ will contain header file 434# dependencies recorded in the .*.cmd file. 435quiet_cmd_link_multi-m = LD [M] $@ 436 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) 437 438$(multi-used-m): FORCE 439 $(call if_changed,link_multi-m) 440$(call multi_depend, $(multi-used-m), .o, -objs -y -m) 441 442targets += $(multi-used-m) 443targets := $(filter-out $(PHONY), $(targets)) 444 445# Add intermediate targets: 446# When building objects with specific suffix patterns, add intermediate 447# targets that the final targets are derived from. 448intermediate_targets = $(foreach sfx, $(2), \ 449 $(patsubst %$(strip $(1)),%$(sfx), \ 450 $(filter %$(strip $(1)), $(targets)))) 451# %.asn1.o <- %.asn1.[ch] <- %.asn1 452# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 453# %.lex.o <- %.lex.c <- %.l 454# %.tab.o <- %.tab.[ch] <- %.y 455targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 456 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 457 $(call intermediate_targets, .lex.o, .lex.c) \ 458 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 459 460# Build 461# --------------------------------------------------------------------------- 462 463ifdef single-build 464 465KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS)) 466 467curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ 468 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) 469 470# Handle single targets without any rule: show "Nothing to be done for ..." or 471# "No rule to make target ..." depending on whether the target exists. 472unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ 473 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS))) 474 475single-subdirs := $(foreach d, $(subdir-ym), \ 476 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d))) 477 478__build: $(curdir-single) $(single-subdirs) 479ifneq ($(unknown-single),) 480 $(Q)$(MAKE) -f /dev/null $(unknown-single) 481endif 482 @: 483 484ifeq ($(curdir-single),) 485# Nothing to do in this directory. Do not include any .*.cmd file for speed-up 486targets := 487else 488targets += $(curdir-single) 489endif 490 491else 492 493__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ 494 $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \ 495 $(subdir-ym) $(always-y) 496 @: 497 498endif 499 500# Descending 501# --------------------------------------------------------------------------- 502 503PHONY += $(subdir-ym) 504$(subdir-ym): 505 $(Q)$(MAKE) $(build)=$@ \ 506 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ 507 need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \ 508 need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1)) 509 510# Add FORCE to the prequisites of a target to force it to be always rebuilt. 511# --------------------------------------------------------------------------- 512 513PHONY += FORCE 514 515FORCE: 516 517# Read all saved command lines and dependencies for the $(targets) we 518# may be building above, using $(if_changed{,_dep}). As an 519# optimization, we don't need to read them if the target does not 520# exist, we will rebuild anyway in that case. 521 522existing-targets := $(wildcard $(sort $(targets))) 523 524-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 525 526ifdef building_out_of_srctree 527# Create directories for object files if they do not exist 528obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets)))) 529# If targets exist, their directories apparently exist. Skip mkdir. 530existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 531obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 532ifneq ($(obj-dirs),) 533$(shell mkdir -p $(obj-dirs)) 534endif 535endif 536 537.PHONY: $(PHONY) 538