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 $(call if_changed_dep,cc_lst_c) 247 248# Compile Rust sources (.rs) 249# --------------------------------------------------------------------------- 250 251rust_allowed_features := new_uninit 252 253# `--out-dir` is required to avoid temporaries being created by `rustc` in the 254# current working directory, which may be not accessible in the out-of-tree 255# modules case. 256rust_common_cmd = \ 257 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ 258 -Zallow-features=$(rust_allowed_features) \ 259 -Zcrate-attr=no_std \ 260 -Zcrate-attr='feature($(rust_allowed_features))' \ 261 -Zunstable-options --extern force:alloc --extern kernel \ 262 --crate-type rlib -L $(objtree)/rust/ \ 263 --crate-name $(basename $(notdir $@)) \ 264 --sysroot=/dev/null \ 265 --out-dir $(dir $@) --emit=dep-info=$(depfile) 266 267# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit 268# will be used. We explicitly request `-Ccodegen-units=1` in any case, and 269# the compiler shows a warning if it is not 1. However, if we ever stop 270# requesting it explicitly and we start using some other `--emit` that does not 271# imply it (and for which codegen is performed), then we would be out of sync, 272# i.e. the outputs we would get for the different single targets (e.g. `.ll`) 273# would not match each other. 274 275quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 276 cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< 277 278$(obj)/%.o: $(obj)/%.rs FORCE 279 +$(call if_changed_dep,rustc_o_rs) 280 281quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 282 cmd_rustc_rsi_rs = \ 283 $(rust_common_cmd) -Zunpretty=expanded $< >$@; \ 284 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@ 285 286$(obj)/%.rsi: $(obj)/%.rs FORCE 287 +$(call if_changed_dep,rustc_rsi_rs) 288 289quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 290 cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $< 291 292$(obj)/%.s: $(obj)/%.rs FORCE 293 +$(call if_changed_dep,rustc_s_rs) 294 295quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 296 cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $< 297 298$(obj)/%.ll: $(obj)/%.rs FORCE 299 +$(call if_changed_dep,rustc_ll_rs) 300 301# Compile assembler sources (.S) 302# --------------------------------------------------------------------------- 303 304# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 305# or a file that it includes, in order to get versioned symbols. We build a 306# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 307# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 308# 309# This is convoluted. The .S file must first be preprocessed to run guards and 310# expand names, then the resulting exports must be constructed into plain 311# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 312# to make the genksyms input. 313# 314# These mirror gensymtypes_c and co above, keep them in synch. 315cmd_gensymtypes_S = \ 316 { echo "\#include <linux/kernel.h>" ; \ 317 echo "\#include <asm/asm-prototypes.h>" ; \ 318 $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \ 319 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) 320 321quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 322 cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null 323 324$(obj)/%.symtypes : $(obj)/%.S FORCE 325 $(call cmd,cc_symtypes_S) 326 327 328quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 329cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 330 331$(obj)/%.s: $(obj)/%.S FORCE 332 $(call if_changed_dep,cpp_s_S) 333 334quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 335 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool) 336 337ifdef CONFIG_ASM_MODVERSIONS 338 339# versioning matches the C process described above, with difference that 340# we parse asm-prototypes.h C header to get function definitions. 341 342cmd_gen_symversions_S = $(call gen_symversions,S) 343 344endif 345 346$(obj)/%.o: $(obj)/%.S FORCE 347 $(call if_changed_rule,as_o_S) 348 349targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 350targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 351targets += $(lib-y) $(always-y) 352 353# Linker scripts preprocessor (.lds.S -> .lds) 354# --------------------------------------------------------------------------- 355quiet_cmd_cpp_lds_S = LDS $@ 356 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 357 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 358 359$(obj)/%.lds: $(src)/%.lds.S FORCE 360 $(call if_changed_dep,cpp_lds_S) 361 362# ASN.1 grammar 363# --------------------------------------------------------------------------- 364quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 365 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 366 $(basename $@).c $(basename $@).h 367 368$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 369 $(call cmd,asn1_compiler) 370 371# Build the compiled-in targets 372# --------------------------------------------------------------------------- 373 374# To build objects in subdirs, we need to descend into the directories 375$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 376$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 377 378# 379# Rule to compile a set of .o files into one .a file (without symbol table) 380# 381# To make this rule robust against "Argument list too long" error, 382# remove $(obj)/ prefix, and restore it by a shell command. 383 384quiet_cmd_ar_builtin = AR $@ 385 cmd_ar_builtin = rm -f $@; \ 386 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \ 387 $(AR) cDPrST $@ 388 389$(obj)/built-in.a: $(real-obj-y) FORCE 390 $(call if_changed,ar_builtin) 391 392# This is a list of build artifacts from the current Makefile and its 393# sub-directories. The timestamp should be updated when any of the member files. 394 395cmd_gen_order = { $(foreach m, $(real-prereqs), \ 396 $(if $(filter %/$(notdir $@), $m), cat $m, echo $m);) :; } \ 397 > $@ 398 399$(obj)/modules.order: $(obj-m) FORCE 400 $(call if_changed,gen_order) 401 402# 403# Rule to compile a set of .o files into one .a file (with symbol table) 404# 405 406$(obj)/lib.a: $(lib-y) FORCE 407 $(call if_changed,ar) 408 409quiet_cmd_ld_multi_m = LD [M] $@ 410 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$< $(cmd_objtool) 411 412define rule_ld_multi_m 413 $(call cmd_and_savecmd,ld_multi_m) 414 $(call cmd,gen_objtooldep) 415endef 416 417$(multi-obj-m): private objtool-enabled := $(delay-objtool) 418$(multi-obj-m): private part-of-module := y 419$(multi-obj-m): %.o: %.mod FORCE 420 $(call if_changed_rule,ld_multi_m) 421$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 422 423# Add intermediate targets: 424# When building objects with specific suffix patterns, add intermediate 425# targets that the final targets are derived from. 426intermediate_targets = $(foreach sfx, $(2), \ 427 $(patsubst %$(strip $(1)),%$(sfx), \ 428 $(filter %$(strip $(1)), $(targets)))) 429# %.asn1.o <- %.asn1.[ch] <- %.asn1 430targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) 431 432# Include additional build rules when necessary 433# --------------------------------------------------------------------------- 434 435# $(sort ...) is used here to remove duplicated words and excessive spaces. 436hostprogs := $(sort $(hostprogs)) 437ifneq ($(hostprogs),) 438include $(srctree)/scripts/Makefile.host 439endif 440 441# $(sort ...) is used here to remove duplicated words and excessive spaces. 442userprogs := $(sort $(userprogs)) 443ifneq ($(userprogs),) 444include $(srctree)/scripts/Makefile.userprogs 445endif 446 447ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets)),) 448include $(srctree)/scripts/Makefile.dtbs 449endif 450 451# Build 452# --------------------------------------------------------------------------- 453 454$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 455 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 456 $(subdir-ym) $(always-y) 457 @: 458 459# Single targets 460# --------------------------------------------------------------------------- 461 462single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d)) 463single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS)) 464 465$(single-subdir-goals): $(single-subdirs) 466 @: 467 468# Descending 469# --------------------------------------------------------------------------- 470 471PHONY += $(subdir-ym) 472$(subdir-ym): 473 $(Q)$(MAKE) $(build)=$@ \ 474 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 475 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \ 476 $(filter $@/%, $(single-subdir-goals)) 477 478# Add FORCE to the prerequisites of a target to force it to be always rebuilt. 479# --------------------------------------------------------------------------- 480 481PHONY += FORCE 482 483FORCE: 484 485targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS)) 486targets := $(filter-out $(PHONY), $(targets)) 487 488# Read all saved command lines and dependencies for the $(targets) we 489# may be building above, using $(if_changed{,_dep}). As an 490# optimization, we don't need to read them if the target does not 491# exist, we will rebuild anyway in that case. 492 493existing-targets := $(wildcard $(sort $(targets))) 494 495-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 496 497# Create directories for object files if they do not exist 498obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 499# If targets exist, their directories apparently exist. Skip mkdir. 500existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 501obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 502ifneq ($(obj-dirs),) 503$(shell mkdir -p $(obj-dirs)) 504endif 505 506.PHONY: $(PHONY) 507