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