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