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