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