1# SPDX-License-Identifier: GPL-2.0 2# ========================================================================== 3# Building 4# ========================================================================== 5 6src := $(if $(VPATH),$(VPATH)/)$(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 41include $(kbuild-file) 42include $(srctree)/scripts/Makefile.lib 43 44ifndef obj 45$(warning kbuild: Makefile.build is included improperly) 46endif 47 48ifeq ($(need-modorder),) 49ifneq ($(obj-m),) 50$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 51$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 52endif 53endif 54 55# =========================================================================== 56 57# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...) 58subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y))) 59subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) 60 61targets-for-builtin := $(extra-y) 62 63ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 64targets-for-builtin += $(obj)/lib.a 65endif 66 67ifdef need-builtin 68targets-for-builtin += $(obj)/built-in.a 69endif 70 71targets-for-modules := $(foreach x, o mod, \ 72 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) 73 74ifdef need-modorder 75targets-for-modules += $(obj)/modules.order 76endif 77 78targets += $(targets-for-builtin) $(targets-for-modules) 79 80# Linus' kernel sanity checking tool 81ifeq ($(KBUILD_CHECKSRC),1) 82 quiet_cmd_checksrc = CHECK $< 83 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 84else ifeq ($(KBUILD_CHECKSRC),2) 85 quiet_cmd_force_checksrc = CHECK $< 86 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 87endif 88 89ifneq ($(KBUILD_EXTRA_WARN),) 90 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $(KDOCFLAGS) \ 91 $(if $(findstring 2, $(KBUILD_EXTRA_WARN)), -Wall) \ 92 $< 93endif 94 95# Compile C sources (.c) 96# --------------------------------------------------------------------------- 97 98quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 99 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< 100 101$(obj)/%.s: $(obj)/%.c FORCE 102 $(call if_changed_dep,cc_s_c) 103 104quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 105cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 106 107$(obj)/%.i: $(obj)/%.c FORCE 108 $(call if_changed_dep,cpp_i_c) 109 110genksyms = scripts/genksyms/genksyms \ 111 $(if $(1), -T $(2)) \ 112 $(if $(KBUILD_PRESERVE), -p) \ 113 -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null) 114 115# These mirror gensymtypes_S and co below, keep them in synch. 116cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) 117 118quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 119 cmd_cc_symtypes_c = $(call cmd_gensymtypes_c,true,$@) >/dev/null 120 121$(obj)/%.symtypes : $(obj)/%.c FORCE 122 $(call cmd,cc_symtypes_c) 123 124# LLVM assembly 125# Generate .ll files from .c 126quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 127 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $< 128 129$(obj)/%.ll: $(obj)/%.c FORCE 130 $(call if_changed_dep,cc_ll_c) 131 132# C (.c) files 133# The C file is compiled and updated dependency information is generated. 134# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 135 136is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) 137 138# When a module consists of a single object, there is no reason to keep LLVM IR. 139# Make $(LD) covert LLVM IR to ELF here. 140ifdef CONFIG_LTO_CLANG 141cmd_ld_single_m = $(if $(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@) 142endif 143 144quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 145 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \ 146 $(cmd_ld_single_m) \ 147 $(cmd_objtool) 148 149ifdef CONFIG_MODVERSIONS 150# When module versioning is enabled the following steps are executed: 151# o compile a <file>.o from <file>.c 152# o if <file>.o doesn't contain a __export_symbol_*, i.e. does 153# not export symbols, it's done. 154# o otherwise, we calculate symbol versions using the good old 155# genksyms on the preprocessed source and dump them into the .cmd file. 156# o modpost will extract versions from that file and create *.c files that will 157# be compiled and linked to the kernel and/or modules. 158 159gen_symversions = \ 160 if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then \ 161 $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 162 >> $(dot-target).cmd; \ 163 fi 164 165cmd_gen_symversions_c = $(call gen_symversions,c) 166 167endif 168 169ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 170# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 171ifdef BUILD_C_RECORDMCOUNT 172ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 173 RECORDMCOUNT_FLAGS = -w 174endif 175# Due to recursion, we must skip empty.o. 176# The empty.o file is created in the make process in order to determine 177# the target endianness and word size. It is made before all other C 178# files, including recordmcount. 179sub_cmd_record_mcount = \ 180 if [ $(@) != "scripts/mod/empty.o" ]; then \ 181 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 182 fi; 183recordmcount_source := $(srctree)/scripts/recordmcount.c \ 184 $(srctree)/scripts/recordmcount.h 185else 186sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 187 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 188 "$(if $(CONFIG_64BIT),64,32)" \ 189 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 190 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 191 "$(if $(part-of-module),1,0)" "$(@)"; 192recordmcount_source := $(srctree)/scripts/recordmcount.pl 193endif # BUILD_C_RECORDMCOUNT 194cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 195 $(sub_cmd_record_mcount)) 196endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 197 198# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 199# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 200# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 201 202is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),$(is-kernel-object)) 203 204$(obj)/%.o: private objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) 205 206ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) 207cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) 208endif 209 210define rule_cc_o_c 211 $(call cmd_and_fixdep,cc_o_c) 212 $(call cmd,checksrc) 213 $(call cmd,checkdoc) 214 $(call cmd,gen_objtooldep) 215 $(call cmd,gen_symversions_c) 216 $(call cmd,record_mcount) 217 $(call cmd,warn_shared_object) 218endef 219 220define rule_as_o_S 221 $(call cmd_and_fixdep,as_o_S) 222 $(call cmd,gen_objtooldep) 223 $(call cmd,gen_symversions_S) 224 $(call cmd,warn_shared_object) 225endef 226 227# Built-in and composite module parts 228$(obj)/%.o: $(obj)/%.c $(recordmcount_source) FORCE 229 $(call if_changed_rule,cc_o_c) 230 $(call cmd,force_checksrc) 231 232# To make this rule robust against "Argument list too long" error, 233# ensure to add $(obj)/ prefix by a shell command. 234cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ 235 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ 236 237$(obj)/%.mod: FORCE 238 $(call if_changed,mod) 239 240quiet_cmd_cc_lst_c = MKLST $@ 241 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 242 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 243 System.map $(OBJDUMP) > $@ 244 245$(obj)/%.lst: $(obj)/%.c FORCE 246 $(call if_changed_dep,cc_lst_c) 247 248# Compile Rust sources (.rs) 249# --------------------------------------------------------------------------- 250 251rust_allowed_features := asm_const,asm_goto,new_uninit 252 253# `--out-dir` is required to avoid temporaries being created by `rustc` in the 254# current working directory, which may be not accessible in the out-of-tree 255# modules case. 256rust_common_cmd = \ 257 OBJTREE=$(abspath $(objtree)) \ 258 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ 259 -Zallow-features=$(rust_allowed_features) \ 260 -Zcrate-attr=no_std \ 261 -Zcrate-attr='feature($(rust_allowed_features))' \ 262 -Zunstable-options --extern force:alloc --extern kernel \ 263 --crate-type rlib -L $(objtree)/rust/ \ 264 --crate-name $(basename $(notdir $@)) \ 265 --sysroot=/dev/null \ 266 --out-dir $(dir $@) --emit=dep-info=$(depfile) 267 268# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit 269# will be used. We explicitly request `-Ccodegen-units=1` in any case, and 270# the compiler shows a warning if it is not 1. However, if we ever stop 271# requesting it explicitly and we start using some other `--emit` that does not 272# imply it (and for which codegen is performed), then we would be out of sync, 273# i.e. the outputs we would get for the different single targets (e.g. `.ll`) 274# would not match each other. 275 276quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 277 cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< $(cmd_objtool) 278 279define rule_rustc_o_rs 280 $(call cmd_and_fixdep,rustc_o_rs) 281 $(call cmd,gen_objtooldep) 282endef 283 284$(obj)/%.o: $(obj)/%.rs FORCE 285 +$(call if_changed_rule,rustc_o_rs) 286 287quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 288 cmd_rustc_rsi_rs = \ 289 $(rust_common_cmd) -Zunpretty=expanded $< >$@; \ 290 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@ 291 292$(obj)/%.rsi: $(obj)/%.rs FORCE 293 +$(call if_changed_dep,rustc_rsi_rs) 294 295quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 296 cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $< 297 298$(obj)/%.s: $(obj)/%.rs FORCE 299 +$(call if_changed_dep,rustc_s_rs) 300 301quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 302 cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $< 303 304$(obj)/%.ll: $(obj)/%.rs FORCE 305 +$(call if_changed_dep,rustc_ll_rs) 306 307quiet_cmd_rustc_rs_rs_S = RSCPP $(quiet_modtag) $@ 308 cmd_rustc_rs_rs_S = $(CPP) $(c_flags) -xc -C -P $< | sed '1,/^\/\/ Cut here.$$/d' >$@ 309 310$(obj)/%.rs: $(obj)/%.rs.S FORCE 311 +$(call if_changed_dep,rustc_rs_rs_S) 312 313# Compile assembler sources (.S) 314# --------------------------------------------------------------------------- 315 316# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 317# or a file that it includes, in order to get versioned symbols. We build a 318# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 319# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 320# 321# This is convoluted. The .S file must first be preprocessed to run guards and 322# expand names, then the resulting exports must be constructed into plain 323# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 324# to make the genksyms input. 325# 326# These mirror gensymtypes_c and co above, keep them in synch. 327cmd_gensymtypes_S = \ 328 { echo "\#include <linux/kernel.h>" ; \ 329 echo "\#include <asm/asm-prototypes.h>" ; \ 330 $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \ 331 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) 332 333quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 334 cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null 335 336$(obj)/%.symtypes : $(obj)/%.S FORCE 337 $(call cmd,cc_symtypes_S) 338 339 340quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 341cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 342 343$(obj)/%.s: $(obj)/%.S FORCE 344 $(call if_changed_dep,cpp_s_S) 345 346quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 347 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool) 348 349ifdef CONFIG_ASM_MODVERSIONS 350 351# versioning matches the C process described above, with difference that 352# we parse asm-prototypes.h C header to get function definitions. 353 354cmd_gen_symversions_S = $(call gen_symversions,S) 355 356endif 357 358$(obj)/%.o: $(obj)/%.S FORCE 359 $(call if_changed_rule,as_o_S) 360 361targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 362targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 363targets += $(lib-y) $(always-y) 364 365# Linker scripts preprocessor (.lds.S -> .lds) 366# --------------------------------------------------------------------------- 367quiet_cmd_cpp_lds_S = LDS $@ 368 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 369 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 370 371$(obj)/%.lds: $(src)/%.lds.S FORCE 372 $(call if_changed_dep,cpp_lds_S) 373 374# ASN.1 grammar 375# --------------------------------------------------------------------------- 376quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 377 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 378 $(basename $@).c $(basename $@).h 379 380$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 381 $(call cmd,asn1_compiler) 382 383# Build the compiled-in targets 384# --------------------------------------------------------------------------- 385 386# To build objects in subdirs, we need to descend into the directories 387$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 388$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 389 390# 391# Rule to compile a set of .o files into one .a file (without symbol table) 392# 393# To make this rule robust against "Argument list too long" error, 394# remove $(obj)/ prefix, and restore it by a shell command. 395 396quiet_cmd_ar_builtin = AR $@ 397 cmd_ar_builtin = rm -f $@; \ 398 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \ 399 $(AR) cDPrST $@ 400 401$(obj)/built-in.a: $(real-obj-y) FORCE 402 $(call if_changed,ar_builtin) 403 404# This is a list of build artifacts from the current Makefile and its 405# sub-directories. The timestamp should be updated when any of the member files. 406 407cmd_gen_order = { $(foreach m, $(real-prereqs), \ 408 $(if $(filter %/$(notdir $@), $m), cat $m, echo $m);) :; } \ 409 > $@ 410 411$(obj)/modules.order: $(obj-m) FORCE 412 $(call if_changed,gen_order) 413 414# 415# Rule to compile a set of .o files into one .a file (with symbol table) 416# 417 418$(obj)/lib.a: $(lib-y) FORCE 419 $(call if_changed,ar) 420 421quiet_cmd_ld_multi_m = LD [M] $@ 422 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$< $(cmd_objtool) 423 424define rule_ld_multi_m 425 $(call cmd_and_savecmd,ld_multi_m) 426 $(call cmd,gen_objtooldep) 427endef 428 429$(multi-obj-m): private objtool-enabled := $(delay-objtool) 430$(multi-obj-m): private part-of-module := y 431$(multi-obj-m): %.o: %.mod FORCE 432 $(call if_changed_rule,ld_multi_m) 433$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 434 435# Add intermediate targets: 436# When building objects with specific suffix patterns, add intermediate 437# targets that the final targets are derived from. 438intermediate_targets = $(foreach sfx, $(2), \ 439 $(patsubst %$(strip $(1)),%$(sfx), \ 440 $(filter %$(strip $(1)), $(targets)))) 441# %.asn1.o <- %.asn1.[ch] <- %.asn1 442targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) 443 444# Include additional build rules when necessary 445# --------------------------------------------------------------------------- 446 447# $(sort ...) is used here to remove duplicated words and excessive spaces. 448hostprogs := $(sort $(hostprogs)) 449ifneq ($(hostprogs),) 450include $(srctree)/scripts/Makefile.host 451endif 452 453# $(sort ...) is used here to remove duplicated words and excessive spaces. 454userprogs := $(sort $(userprogs)) 455ifneq ($(userprogs),) 456include $(srctree)/scripts/Makefile.userprogs 457endif 458 459ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets)),) 460include $(srctree)/scripts/Makefile.dtbs 461endif 462 463# Build 464# --------------------------------------------------------------------------- 465 466$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 467 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 468 $(subdir-ym) $(always-y) 469 @: 470 471# Single targets 472# --------------------------------------------------------------------------- 473 474single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d)) 475single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS)) 476 477$(single-subdir-goals): $(single-subdirs) 478 @: 479 480# Descending 481# --------------------------------------------------------------------------- 482 483PHONY += $(subdir-ym) 484$(subdir-ym): 485 $(Q)$(MAKE) $(build)=$@ \ 486 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 487 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \ 488 $(filter $@/%, $(single-subdir-goals)) 489 490# Add FORCE to the prerequisites of a target to force it to be always rebuilt. 491# --------------------------------------------------------------------------- 492 493PHONY += FORCE 494 495FORCE: 496 497targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS)) 498targets := $(filter-out $(PHONY), $(targets)) 499 500# Read all saved command lines and dependencies for the $(targets) we 501# may be building above, using $(if_changed{,_dep}). As an 502# optimization, we don't need to read them if the target does not 503# exist, we will rebuild anyway in that case. 504 505existing-targets := $(wildcard $(sort $(targets))) 506 507-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 508 509# Create directories for object files if they do not exist 510obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 511# If targets exist, their directories apparently exist. Skip mkdir. 512existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 513obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 514ifneq ($(obj-dirs),) 515$(shell mkdir -p $(obj-dirs)) 516endif 517 518.PHONY: $(PHONY) 519