1# SPDX-License-Identifier: GPL-2.0 2# ========================================================================== 3# Building 4# ========================================================================== 5 6src := $(obj) 7 8PHONY := $(obj)/ 9$(obj)/: 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-y := 19always-m := 20targets := 21subdir-y := 22subdir-m := 23EXTRA_AFLAGS := 24EXTRA_CFLAGS := 25EXTRA_CPPFLAGS := 26EXTRA_LDFLAGS := 27asflags-y := 28ccflags-y := 29rustflags-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 $(srctree)/scripts/Kbuild.include 40include $(srctree)/scripts/Makefile.compiler 41 42# The filename Kbuild has precedence over Makefile 43kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 44include $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile) 45 46include $(srctree)/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 $(srctree)/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 $(srctree)/scripts/Makefile.userprogs 60endif 61 62ifndef obj 63$(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 := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \ 90 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) 91 92ifdef need-modorder 93targets-for-modules += $(obj)/modules.order 94endif 95 96targets += $(targets-for-builtin) $(targets-for-modules) 97 98# Linus' kernel sanity checking tool 99ifeq ($(KBUILD_CHECKSRC),1) 100 quiet_cmd_checksrc = CHECK $< 101 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 102else ifeq ($(KBUILD_CHECKSRC),2) 103 quiet_cmd_force_checksrc = CHECK $< 104 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 105endif 106 107ifneq ($(KBUILD_EXTRA_WARN),) 108 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 109endif 110 111# Compile C sources (.c) 112# --------------------------------------------------------------------------- 113 114quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 115 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< 116 117$(obj)/%.s: $(src)/%.c FORCE 118 $(call if_changed_dep,cc_s_c) 119 120quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 121cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 122 123$(obj)/%.i: $(src)/%.c FORCE 124 $(call if_changed_dep,cpp_i_c) 125 126genksyms = scripts/genksyms/genksyms \ 127 $(if $(1), -T $(2)) \ 128 $(if $(KBUILD_PRESERVE), -p) \ 129 -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null) 130 131# These mirror gensymtypes_S and co below, keep them in synch. 132cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) 133 134quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 135 cmd_cc_symtypes_c = $(call cmd_gensymtypes_c,true,$@) >/dev/null 136 137$(obj)/%.symtypes : $(src)/%.c FORCE 138 $(call cmd,cc_symtypes_c) 139 140# LLVM assembly 141# Generate .ll files from .c 142quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 143 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $< 144 145$(obj)/%.ll: $(src)/%.c FORCE 146 $(call if_changed_dep,cc_ll_c) 147 148# C (.c) files 149# The C file is compiled and updated dependency information is generated. 150# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 151 152is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) 153 154# When a module consists of a single object, there is no reason to keep LLVM IR. 155# Make $(LD) covert LLVM IR to ELF here. 156ifdef CONFIG_LTO_CLANG 157cmd_ld_single_m = $(if $(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@) 158endif 159 160quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 161 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \ 162 $(cmd_ld_single_m) \ 163 $(cmd_objtool) 164 165ifdef CONFIG_MODVERSIONS 166# When module versioning is enabled the following steps are executed: 167# o compile a <file>.o from <file>.c 168# o if <file>.o doesn't contain a __ksymtab version, i.e. does 169# not export symbols, it's done. 170# o otherwise, we calculate symbol versions using the good old 171# genksyms on the preprocessed source and dump them into the .cmd file. 172# o modpost will extract versions from that file and create *.c files that will 173# be compiled and linked to the kernel and/or modules. 174 175gen_symversions = \ 176 if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ 177 $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 178 >> $(dot-target).cmd; \ 179 fi 180 181cmd_gen_symversions_c = $(call gen_symversions,c) 182 183endif 184 185ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 186# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 187ifdef BUILD_C_RECORDMCOUNT 188ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 189 RECORDMCOUNT_FLAGS = -w 190endif 191# Due to recursion, we must skip empty.o. 192# The empty.o file is created in the make process in order to determine 193# the target endianness and word size. It is made before all other C 194# files, including recordmcount. 195sub_cmd_record_mcount = \ 196 if [ $(@) != "scripts/mod/empty.o" ]; then \ 197 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 198 fi; 199recordmcount_source := $(srctree)/scripts/recordmcount.c \ 200 $(srctree)/scripts/recordmcount.h 201else 202sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 203 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 204 "$(if $(CONFIG_64BIT),64,32)" \ 205 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 206 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 207 "$(if $(part-of-module),1,0)" "$(@)"; 208recordmcount_source := $(srctree)/scripts/recordmcount.pl 209endif # BUILD_C_RECORDMCOUNT 210cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 211 $(sub_cmd_record_mcount)) 212endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 213 214# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 215# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 216# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 217 218is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y) 219 220$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) 221 222ifdef CONFIG_TRIM_UNUSED_KSYMS 223cmd_gen_ksymdeps = \ 224 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 225endif 226 227cmd_check_local_export = $(srctree)/scripts/check-local-export $@ 228 229define rule_cc_o_c 230 $(call cmd_and_fixdep,cc_o_c) 231 $(call cmd,gen_ksymdeps) 232 $(call cmd,check_local_export) 233 $(call cmd,checksrc) 234 $(call cmd,checkdoc) 235 $(call cmd,gen_objtooldep) 236 $(call cmd,gen_symversions_c) 237 $(call cmd,record_mcount) 238endef 239 240define rule_as_o_S 241 $(call cmd_and_fixdep,as_o_S) 242 $(call cmd,gen_ksymdeps) 243 $(call cmd,check_local_export) 244 $(call cmd,gen_objtooldep) 245 $(call cmd,gen_symversions_S) 246endef 247 248# Built-in and composite module parts 249$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE 250 $(call if_changed_rule,cc_o_c) 251 $(call cmd,force_checksrc) 252 253# To make this rule robust against "Argument list too long" error, 254# ensure to add $(obj)/ prefix by a shell command. 255cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ 256 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ 257 258$(obj)/%.mod: FORCE 259 $(call if_changed,mod) 260 261# List module undefined symbols 262cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@ 263 264$(obj)/%.usyms: $(obj)/%.o FORCE 265 $(call if_changed,undefined_syms) 266 267quiet_cmd_cc_lst_c = MKLST $@ 268 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 269 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 270 System.map $(OBJDUMP) > $@ 271 272$(obj)/%.lst: $(src)/%.c FORCE 273 $(call if_changed_dep,cc_lst_c) 274 275# Compile Rust sources (.rs) 276# --------------------------------------------------------------------------- 277 278rust_allowed_features := core_ffi_c 279 280rust_common_cmd = \ 281 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ 282 -Zallow-features=$(rust_allowed_features) \ 283 -Zcrate-attr=no_std \ 284 -Zcrate-attr='feature($(rust_allowed_features))' \ 285 --extern alloc --extern kernel \ 286 --crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \ 287 --crate-name $(basename $(notdir $@)) 288 289rust_handle_depfile = \ 290 mv $(obj)/$(basename $(notdir $@)).d $(depfile); \ 291 sed -i '/^\#/d' $(depfile) 292 293# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit 294# will be used. We explicitly request `-Ccodegen-units=1` in any case, and 295# the compiler shows a warning if it is not 1. However, if we ever stop 296# requesting it explicitly and we start using some other `--emit` that does not 297# imply it (and for which codegen is performed), then we would be out of sync, 298# i.e. the outputs we would get for the different single targets (e.g. `.ll`) 299# would not match each other. 300 301quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 302 cmd_rustc_o_rs = \ 303 $(rust_common_cmd) --emit=dep-info,obj $<; \ 304 $(rust_handle_depfile) 305 306$(obj)/%.o: $(src)/%.rs FORCE 307 $(call if_changed_dep,rustc_o_rs) 308 309quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 310 cmd_rustc_rsi_rs = \ 311 $(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \ 312 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \ 313 $(rust_handle_depfile) 314 315$(obj)/%.rsi: $(src)/%.rs FORCE 316 $(call if_changed_dep,rustc_rsi_rs) 317 318quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 319 cmd_rustc_s_rs = \ 320 $(rust_common_cmd) --emit=dep-info,asm $<; \ 321 $(rust_handle_depfile) 322 323$(obj)/%.s: $(src)/%.rs FORCE 324 $(call if_changed_dep,rustc_s_rs) 325 326quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 327 cmd_rustc_ll_rs = \ 328 $(rust_common_cmd) --emit=dep-info,llvm-ir $<; \ 329 $(rust_handle_depfile) 330 331$(obj)/%.ll: $(src)/%.rs FORCE 332 $(call if_changed_dep,rustc_ll_rs) 333 334# Compile assembler sources (.S) 335# --------------------------------------------------------------------------- 336 337# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 338# or a file that it includes, in order to get versioned symbols. We build a 339# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 340# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 341# 342# This is convoluted. The .S file must first be preprocessed to run guards and 343# expand names, then the resulting exports must be constructed into plain 344# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 345# to make the genksyms input. 346# 347# These mirror gensymtypes_c and co above, keep them in synch. 348cmd_gensymtypes_S = \ 349 { echo "\#include <linux/kernel.h>" ; \ 350 echo "\#include <asm/asm-prototypes.h>" ; \ 351 $(CPP) $(a_flags) $< | \ 352 grep "\<___EXPORT_SYMBOL\>" | \ 353 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 354 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) 355 356quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 357 cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null 358 359$(obj)/%.symtypes : $(src)/%.S FORCE 360 $(call cmd,cc_symtypes_S) 361 362 363quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 364cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 365 366$(obj)/%.s: $(src)/%.S FORCE 367 $(call if_changed_dep,cpp_s_S) 368 369quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 370 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool) 371 372ifdef CONFIG_ASM_MODVERSIONS 373 374# versioning matches the C process described above, with difference that 375# we parse asm-prototypes.h C header to get function definitions. 376 377cmd_gen_symversions_S = $(call gen_symversions,S) 378 379endif 380 381$(obj)/%.o: $(src)/%.S FORCE 382 $(call if_changed_rule,as_o_S) 383 384targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 385targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 386targets += $(real-dtb-y) $(lib-y) $(always-y) 387 388# Linker scripts preprocessor (.lds.S -> .lds) 389# --------------------------------------------------------------------------- 390quiet_cmd_cpp_lds_S = LDS $@ 391 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 392 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 393 394$(obj)/%.lds: $(src)/%.lds.S FORCE 395 $(call if_changed_dep,cpp_lds_S) 396 397# ASN.1 grammar 398# --------------------------------------------------------------------------- 399quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 400 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 401 $(basename $@).c $(basename $@).h 402 403$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 404 $(call cmd,asn1_compiler) 405 406# Build the compiled-in targets 407# --------------------------------------------------------------------------- 408 409# To build objects in subdirs, we need to descend into the directories 410$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 411$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 412 413# 414# Rule to compile a set of .o files into one .a file (without symbol table) 415# 416# To make this rule robust against "Argument list too long" error, 417# remove $(obj)/ prefix, and restore it by a shell command. 418 419quiet_cmd_ar_builtin = AR $@ 420 cmd_ar_builtin = rm -f $@; \ 421 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \ 422 $(AR) cDPrST $@ 423 424$(obj)/built-in.a: $(real-obj-y) FORCE 425 $(call if_changed,ar_builtin) 426 427# 428# Rule to create modules.order file 429# 430# Create commands to either record .ko file or cat modules.order from 431# a subdirectory 432# Add $(obj-m) as the prerequisite to avoid updating the timestamp of 433# modules.order unless contained modules are updated. 434 435cmd_modules_order = { $(foreach m, $(real-prereqs), \ 436 $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \ 437 > $@ 438 439$(obj)/modules.order: $(obj-m) FORCE 440 $(call if_changed,modules_order) 441 442# 443# Rule to compile a set of .o files into one .a file (with symbol table) 444# 445 446$(obj)/lib.a: $(lib-y) FORCE 447 $(call if_changed,ar) 448 449quiet_cmd_ld_multi_m = LD [M] $@ 450 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) $(cmd_objtool) 451 452define rule_ld_multi_m 453 $(call cmd_and_savecmd,ld_multi_m) 454 $(call cmd,gen_objtooldep) 455endef 456 457$(multi-obj-m): objtool-enabled := $(delay-objtool) 458$(multi-obj-m): part-of-module := y 459$(multi-obj-m): %.o: %.mod FORCE 460 $(call if_changed_rule,ld_multi_m) 461$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 462 463# Add intermediate targets: 464# When building objects with specific suffix patterns, add intermediate 465# targets that the final targets are derived from. 466intermediate_targets = $(foreach sfx, $(2), \ 467 $(patsubst %$(strip $(1)),%$(sfx), \ 468 $(filter %$(strip $(1)), $(targets)))) 469# %.asn1.o <- %.asn1.[ch] <- %.asn1 470# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 471# %.lex.o <- %.lex.c <- %.l 472# %.tab.o <- %.tab.[ch] <- %.y 473targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 474 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 475 $(call intermediate_targets, .lex.o, .lex.c) \ 476 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 477 478# Build 479# --------------------------------------------------------------------------- 480 481$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 482 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 483 $(subdir-ym) $(always-y) 484 @: 485 486# Single targets 487# --------------------------------------------------------------------------- 488 489single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d)) 490single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS)) 491 492$(single-subdir-goals): $(single-subdirs) 493 @: 494 495# Descending 496# --------------------------------------------------------------------------- 497 498PHONY += $(subdir-ym) 499$(subdir-ym): 500 $(Q)$(MAKE) $(build)=$@ \ 501 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 502 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \ 503 $(filter $@/%, $(single-subdir-goals)) 504 505# Add FORCE to the prequisites of a target to force it to be always rebuilt. 506# --------------------------------------------------------------------------- 507 508PHONY += FORCE 509 510FORCE: 511 512targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS)) 513targets := $(filter-out $(PHONY), $(targets)) 514 515# Read all saved command lines and dependencies for the $(targets) we 516# may be building above, using $(if_changed{,_dep}). As an 517# optimization, we don't need to read them if the target does not 518# exist, we will rebuild anyway in that case. 519 520existing-targets := $(wildcard $(sort $(targets))) 521 522-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 523 524# Create directories for object files if they do not exist 525obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 526# If targets exist, their directories apparently exist. Skip mkdir. 527existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 528obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 529ifneq ($(obj-dirs),) 530$(shell mkdir -p $(obj-dirs)) 531endif 532 533.PHONY: $(PHONY) 534