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))) 74 75targets-for-builtin := $(extra-y) 76 77ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 78targets-for-builtin += $(obj)/lib.a 79endif 80 81ifdef need-builtin 82targets-for-builtin += $(obj)/built-in.a 83endif 84 85targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \ 86 $(patsubst %.o, %.$x, $(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) $(CC_FLAGS_LTO), $(c_flags)) -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 122genksyms = scripts/genksyms/genksyms \ 123 $(if $(1), -T $(2)) \ 124 $(if $(KBUILD_PRESERVE), -p) \ 125 -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null) 126 127# These mirror gensymtypes_S and co below, keep them in synch. 128cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) 129 130quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 131 cmd_cc_symtypes_c = $(call cmd_gensymtypes_c,true,$@) >/dev/null 132 133$(obj)/%.symtypes : $(src)/%.c FORCE 134 $(call cmd,cc_symtypes_c) 135 136# LLVM assembly 137# Generate .ll files from .c 138quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 139 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $< 140 141$(obj)/%.ll: $(src)/%.c FORCE 142 $(call if_changed_dep,cc_ll_c) 143 144# C (.c) files 145# The C file is compiled and updated dependency information is generated. 146# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 147 148is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) 149 150# When a module consists of a single object, there is no reason to keep LLVM IR. 151# Make $(LD) covert LLVM IR to ELF here. 152ifdef CONFIG_LTO_CLANG 153cmd_ld_single_m = $(if $(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@) 154endif 155 156quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 157 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \ 158 $(cmd_ld_single_m) \ 159 $(cmd_objtool) 160 161ifdef CONFIG_MODVERSIONS 162# When module versioning is enabled the following steps are executed: 163# o compile a <file>.o from <file>.c 164# o if <file>.o doesn't contain a __ksymtab version, i.e. does 165# not export symbols, it's done. 166# o otherwise, we calculate symbol versions using the good old 167# genksyms on the preprocessed source and dump them into the .cmd file. 168# o modpost will extract versions from that file and create *.c files that will 169# be compiled and linked to the kernel and/or modules. 170 171gen_symversions = \ 172 if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ 173 $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 174 >> $(dot-target).cmd; \ 175 fi 176 177cmd_gen_symversions_c = $(call gen_symversions,c) 178 179endif 180 181ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 182# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 183ifdef BUILD_C_RECORDMCOUNT 184ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 185 RECORDMCOUNT_FLAGS = -w 186endif 187# Due to recursion, we must skip empty.o. 188# The empty.o file is created in the make process in order to determine 189# the target endianness and word size. It is made before all other C 190# files, including recordmcount. 191sub_cmd_record_mcount = \ 192 if [ $(@) != "scripts/mod/empty.o" ]; then \ 193 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 194 fi; 195recordmcount_source := $(srctree)/scripts/recordmcount.c \ 196 $(srctree)/scripts/recordmcount.h 197else 198sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 199 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 200 "$(if $(CONFIG_64BIT),64,32)" \ 201 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 202 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 203 "$(if $(part-of-module),1,0)" "$(@)"; 204recordmcount_source := $(srctree)/scripts/recordmcount.pl 205endif # BUILD_C_RECORDMCOUNT 206cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 207 $(sub_cmd_record_mcount)) 208endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 209 210# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 211# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 212# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 213 214is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y) 215 216$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) 217 218ifdef CONFIG_TRIM_UNUSED_KSYMS 219cmd_gen_ksymdeps = \ 220 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 221endif 222 223cmd_check_local_export = $(srctree)/scripts/check-local-export $@ 224 225ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) 226cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) 227endif 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) 238 $(call cmd,warn_shared_object) 239endef 240 241define rule_as_o_S 242 $(call cmd_and_fixdep,as_o_S) 243 $(call cmd,gen_ksymdeps) 244 $(call cmd,check_local_export) 245 $(call cmd,gen_objtooldep) 246 $(call cmd,gen_symversions_S) 247 $(call cmd,warn_shared_object) 248endef 249 250# Built-in and composite module parts 251$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE 252 $(call if_changed_rule,cc_o_c) 253 $(call cmd,force_checksrc) 254 255# To make this rule robust against "Argument list too long" error, 256# ensure to add $(obj)/ prefix by a shell command. 257cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ 258 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ 259 260$(obj)/%.mod: FORCE 261 $(call if_changed,mod) 262 263# List module undefined symbols 264cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@ 265 266$(obj)/%.usyms: $(obj)/%.o FORCE 267 $(call if_changed,undefined_syms) 268 269quiet_cmd_cc_lst_c = MKLST $@ 270 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 271 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 272 System.map $(OBJDUMP) > $@ 273 274$(obj)/%.lst: $(src)/%.c FORCE 275 $(call if_changed_dep,cc_lst_c) 276 277# Compile Rust sources (.rs) 278# --------------------------------------------------------------------------- 279 280rust_allowed_features := core_ffi_c 281 282rust_common_cmd = \ 283 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ 284 -Zallow-features=$(rust_allowed_features) \ 285 -Zcrate-attr=no_std \ 286 -Zcrate-attr='feature($(rust_allowed_features))' \ 287 --extern alloc --extern kernel \ 288 --crate-type rlib -L $(objtree)/rust/ \ 289 --crate-name $(basename $(notdir $@)) \ 290 --emit=dep-info=$(depfile) 291 292# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit 293# will be used. We explicitly request `-Ccodegen-units=1` in any case, and 294# the compiler shows a warning if it is not 1. However, if we ever stop 295# requesting it explicitly and we start using some other `--emit` that does not 296# imply it (and for which codegen is performed), then we would be out of sync, 297# i.e. the outputs we would get for the different single targets (e.g. `.ll`) 298# would not match each other. 299 300quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 301 cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< 302 303$(obj)/%.o: $(src)/%.rs FORCE 304 $(call if_changed_dep,rustc_o_rs) 305 306quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 307 cmd_rustc_rsi_rs = \ 308 $(rust_common_cmd) -Zunpretty=expanded $< >$@; \ 309 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@ 310 311$(obj)/%.rsi: $(src)/%.rs FORCE 312 $(call if_changed_dep,rustc_rsi_rs) 313 314quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 315 cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $< 316 317$(obj)/%.s: $(src)/%.rs FORCE 318 $(call if_changed_dep,rustc_s_rs) 319 320quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 321 cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $< 322 323$(obj)/%.ll: $(src)/%.rs FORCE 324 $(call if_changed_dep,rustc_ll_rs) 325 326# Compile assembler sources (.S) 327# --------------------------------------------------------------------------- 328 329# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 330# or a file that it includes, in order to get versioned symbols. We build a 331# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 332# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 333# 334# This is convoluted. The .S file must first be preprocessed to run guards and 335# expand names, then the resulting exports must be constructed into plain 336# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 337# to make the genksyms input. 338# 339# These mirror gensymtypes_c and co above, keep them in synch. 340cmd_gensymtypes_S = \ 341 { echo "\#include <linux/kernel.h>" ; \ 342 echo "\#include <asm/asm-prototypes.h>" ; \ 343 $(CPP) $(a_flags) $< | \ 344 grep "\<___EXPORT_SYMBOL\>" | \ 345 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 346 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) 347 348quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 349 cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null 350 351$(obj)/%.symtypes : $(src)/%.S FORCE 352 $(call cmd,cc_symtypes_S) 353 354 355quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 356cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 357 358$(obj)/%.s: $(src)/%.S FORCE 359 $(call if_changed_dep,cpp_s_S) 360 361quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 362 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool) 363 364ifdef CONFIG_ASM_MODVERSIONS 365 366# versioning matches the C process described above, with difference that 367# we parse asm-prototypes.h C header to get function definitions. 368 369cmd_gen_symversions_S = $(call gen_symversions,S) 370 371endif 372 373$(obj)/%.o: $(src)/%.S FORCE 374 $(call if_changed_rule,as_o_S) 375 376targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 377targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 378targets += $(real-dtb-y) $(lib-y) $(always-y) 379 380# Linker scripts preprocessor (.lds.S -> .lds) 381# --------------------------------------------------------------------------- 382quiet_cmd_cpp_lds_S = LDS $@ 383 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 384 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 385 386$(obj)/%.lds: $(src)/%.lds.S FORCE 387 $(call if_changed_dep,cpp_lds_S) 388 389# ASN.1 grammar 390# --------------------------------------------------------------------------- 391quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 392 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 393 $(basename $@).c $(basename $@).h 394 395$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 396 $(call cmd,asn1_compiler) 397 398# Build the compiled-in targets 399# --------------------------------------------------------------------------- 400 401# To build objects in subdirs, we need to descend into the directories 402$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 403$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 404 405# 406# Rule to compile a set of .o files into one .a file (without symbol table) 407# 408# To make this rule robust against "Argument list too long" error, 409# remove $(obj)/ prefix, and restore it by a shell command. 410 411quiet_cmd_ar_builtin = AR $@ 412 cmd_ar_builtin = rm -f $@; \ 413 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \ 414 $(AR) cDPrST $@ 415 416$(obj)/built-in.a: $(real-obj-y) FORCE 417 $(call if_changed,ar_builtin) 418 419# 420# Rule to create modules.order file 421# 422# Create commands to either record .ko file or cat modules.order from 423# a subdirectory 424# Add $(obj-m) as the prerequisite to avoid updating the timestamp of 425# modules.order unless contained modules are updated. 426 427cmd_modules_order = { $(foreach m, $(real-prereqs), \ 428 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \ 429 > $@ 430 431$(obj)/modules.order: $(obj-m) FORCE 432 $(call if_changed,modules_order) 433 434# 435# Rule to compile a set of .o files into one .a file (with symbol table) 436# 437 438$(obj)/lib.a: $(lib-y) FORCE 439 $(call if_changed,ar) 440 441quiet_cmd_ld_multi_m = LD [M] $@ 442 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) $(cmd_objtool) 443 444define rule_ld_multi_m 445 $(call cmd_and_savecmd,ld_multi_m) 446 $(call cmd,gen_objtooldep) 447endef 448 449$(multi-obj-m): objtool-enabled := $(delay-objtool) 450$(multi-obj-m): part-of-module := y 451$(multi-obj-m): %.o: %.mod FORCE 452 $(call if_changed_rule,ld_multi_m) 453$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 454 455# Add intermediate targets: 456# When building objects with specific suffix patterns, add intermediate 457# targets that the final targets are derived from. 458intermediate_targets = $(foreach sfx, $(2), \ 459 $(patsubst %$(strip $(1)),%$(sfx), \ 460 $(filter %$(strip $(1)), $(targets)))) 461# %.asn1.o <- %.asn1.[ch] <- %.asn1 462# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 463# %.dtbo.o <- %.dtbo.S <- %.dtbo <- %.dtso 464# %.lex.o <- %.lex.c <- %.l 465# %.tab.o <- %.tab.[ch] <- %.y 466targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 467 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 468 $(call intermediate_targets, .dtbo.o, .dtbo.S .dtbo) \ 469 $(call intermediate_targets, .lex.o, .lex.c) \ 470 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 471 472# Build 473# --------------------------------------------------------------------------- 474 475$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 476 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 477 $(subdir-ym) $(always-y) 478 @: 479 480# Single targets 481# --------------------------------------------------------------------------- 482 483single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d)) 484single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS)) 485 486$(single-subdir-goals): $(single-subdirs) 487 @: 488 489# Descending 490# --------------------------------------------------------------------------- 491 492PHONY += $(subdir-ym) 493$(subdir-ym): 494 $(Q)$(MAKE) $(build)=$@ \ 495 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 496 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \ 497 $(filter $@/%, $(single-subdir-goals)) 498 499# Add FORCE to the prequisites of a target to force it to be always rebuilt. 500# --------------------------------------------------------------------------- 501 502PHONY += FORCE 503 504FORCE: 505 506targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS)) 507targets := $(filter-out $(PHONY), $(targets)) 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) 517 518# Create directories for object files if they do not exist 519obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 520# If targets exist, their directories apparently exist. Skip mkdir. 521existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 522obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 523ifneq ($(obj-dirs),) 524$(shell mkdir -p $(obj-dirs)) 525endif 526 527.PHONY: $(PHONY) 528