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