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 := 23asflags-y := 24ccflags-y := 25rustflags-y := 26cppflags-y := 27ldflags-y := 28 29subdir-asflags-y := 30subdir-ccflags-y := 31 32# Read auto.conf if it exists, otherwise ignore 33-include $(objtree)/include/config/auto.conf 34 35include $(srctree)/scripts/Kbuild.include 36include $(srctree)/scripts/Makefile.compiler 37include $(kbuild-file) 38include $(srctree)/scripts/Makefile.lib 39 40ifndef obj 41$(warning kbuild: Makefile.build is included improperly) 42endif 43 44ifeq ($(need-modorder),) 45ifneq ($(obj-m),) 46$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 47$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 48endif 49endif 50 51# =========================================================================== 52 53# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...) 54subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y))) 55subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) 56 57targets-for-builtin := $(extra-y) 58 59ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 60targets-for-builtin += $(obj)/lib.a 61endif 62 63ifdef need-builtin 64targets-for-builtin += $(obj)/built-in.a 65endif 66 67targets-for-modules := $(foreach x, o mod, \ 68 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) 69 70ifdef need-modorder 71targets-for-modules += $(obj)/modules.order 72endif 73 74targets += $(targets-for-builtin) $(targets-for-modules) 75 76# Linus' kernel sanity checking tool 77ifeq ($(KBUILD_CHECKSRC),1) 78 quiet_cmd_checksrc = CHECK $< 79 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 80else ifeq ($(KBUILD_CHECKSRC),2) 81 quiet_cmd_force_checksrc = CHECK $< 82 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 83endif 84 85ifneq ($(KBUILD_EXTRA_WARN),) 86 cmd_checkdoc = PYTHONDONTWRITEBYTECODE=1 $(KERNELDOC) -none $(KDOCFLAGS) \ 87 $(if $(findstring 2, $(KBUILD_EXTRA_WARN)), -Wall) \ 88 $< 89endif 90 91# Compile C sources (.c) 92# --------------------------------------------------------------------------- 93 94quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 95 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< 96 97$(obj)/%.s: $(obj)/%.c FORCE 98 $(call if_changed_dep,cc_s_c) 99 100quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 101cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 102 103$(obj)/%.i: $(obj)/%.c FORCE 104 $(call if_changed_dep,cpp_i_c) 105 106getexportsymbols = $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/$(1)/p' 107 108gendwarfksyms = $(objtree)/scripts/gendwarfksyms/gendwarfksyms \ 109 $(if $(KBUILD_SYMTYPES), --symtypes $(@:.o=.symtypes)) \ 110 $(if $(KBUILD_GENDWARFKSYMS_STABLE), --stable) 111 112genksyms = $(objtree)/scripts/genksyms/genksyms \ 113 $(if $(KBUILD_SYMTYPES), -T $(@:.o=.symtypes)) \ 114 $(if $(KBUILD_PRESERVE), -p) \ 115 $(addprefix -r , $(wildcard $(@:.o=.symref))) 116 117# These mirror gensymtypes_S and co below, keep them in synch. 118ifdef CONFIG_GENDWARFKSYMS 119cmd_gensymtypes_c = $(if $(skip_gendwarfksyms),, \ 120 $(call getexportsymbols,\1) | $(gendwarfksyms) $@) 121else 122cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) 123endif # CONFIG_GENDWARFKSYMS 124 125# LLVM assembly 126# Generate .ll files from .c 127quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 128 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $< 129 130$(obj)/%.ll: $(obj)/%.c FORCE 131 $(call if_changed_dep,cc_ll_c) 132 133# C (.c) files 134# The C file is compiled and updated dependency information is generated. 135# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 136 137is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) 138 139ifdef CONFIG_MODVERSIONS 140# When module versioning is enabled the following steps are executed: 141# o compile a <file>.o from <file>.c 142# o if <file>.o doesn't contain a __export_symbol_*, i.e. does 143# not export symbols, it's done. 144# o otherwise, we calculate symbol versions using the good old 145# genksyms on the preprocessed source and dump them into the .cmd file. 146# o modpost will extract versions from that file and create *.c files that will 147# be compiled and linked to the kernel and/or modules. 148 149gen_symversions = \ 150 if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then \ 151 $(cmd_gensymtypes_$1) >> $(dot-target).cmd; \ 152 fi 153 154cmd_gen_symversions_c = $(call gen_symversions,c) 155 156endif 157 158ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 159# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 160ifdef BUILD_C_RECORDMCOUNT 161ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 162 RECORDMCOUNT_FLAGS = -w 163endif 164# Due to recursion, we must skip empty.o. 165# The empty.o file is created in the make process in order to determine 166# the target endianness and word size. It is made before all other C 167# files, including recordmcount. 168sub_cmd_record_mcount = \ 169 if [ $(@) != "scripts/mod/empty.o" ]; then \ 170 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 171 fi; 172recordmcount_source := $(srctree)/scripts/recordmcount.c \ 173 $(srctree)/scripts/recordmcount.h 174else 175sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 176 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 177 "$(if $(CONFIG_64BIT),64,32)" \ 178 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 179 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 180 "$(if $(part-of-module),1,0)" "$(@)"; 181recordmcount_source := $(srctree)/scripts/recordmcount.pl 182endif # BUILD_C_RECORDMCOUNT 183cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 184 $(sub_cmd_record_mcount)) 185endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 186 187# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 188# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 189# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 190 191is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),$(is-kernel-object)) 192 193ifdef CONFIG_OBJTOOL 194$(obj)/%.o: private objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) 195endif 196 197ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) 198cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) 199endif 200 201# Built-in and composite module parts 202$(obj)/%.o: $(obj)/%.c $(recordmcount_source) FORCE 203 $(call if_changed_rule,cc_o_c) 204 $(call cmd,force_checksrc) 205 206# To make this rule robust against "Argument list too long" error, 207# ensure to add $(obj)/ prefix by a shell command. 208cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ 209 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ 210 211$(obj)/%.mod: FORCE 212 $(call if_changed,mod) 213 214quiet_cmd_cc_lst_c = MKLST $@ 215 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 216 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 217 System.map $(OBJDUMP) > $@ 218 219$(obj)/%.lst: $(obj)/%.c FORCE 220 $(call if_changed_dep,cc_lst_c) 221 222# Compile Rust sources (.rs) 223# --------------------------------------------------------------------------- 224 225# The features in this list are the ones allowed for non-`rust/` code. 226# 227# - Stable since Rust 1.81.0: `feature(lint_reasons)`. 228# - Stable since Rust 1.82.0: `feature(asm_const)`, `feature(raw_ref_op)`. 229# - Stable since Rust 1.87.0: `feature(asm_goto)`. 230# - Expected to become stable: `feature(arbitrary_self_types)`. 231# 232# Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on 233# the unstable features in use. 234rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,raw_ref_op 235 236# `--out-dir` is required to avoid temporaries being created by `rustc` in the 237# current working directory, which may be not accessible in the out-of-tree 238# modules case. 239rust_common_cmd = \ 240 OBJTREE=$(abspath $(objtree)) \ 241 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ 242 -Zallow-features=$(rust_allowed_features) \ 243 -Zcrate-attr=no_std \ 244 -Zcrate-attr='feature($(rust_allowed_features))' \ 245 -Zunstable-options --extern pin_init --extern kernel \ 246 --crate-type rlib -L $(objtree)/rust/ \ 247 --crate-name $(basename $(notdir $@)) \ 248 --sysroot=/dev/null \ 249 --out-dir $(dir $@) --emit=dep-info=$(depfile) 250 251# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit 252# will be used. We explicitly request `-Ccodegen-units=1` in any case, and 253# the compiler shows a warning if it is not 1. However, if we ever stop 254# requesting it explicitly and we start using some other `--emit` that does not 255# imply it (and for which codegen is performed), then we would be out of sync, 256# i.e. the outputs we would get for the different single targets (e.g. `.ll`) 257# would not match each other. 258 259quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 260 cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< $(cmd_objtool) 261 262define rule_rustc_o_rs 263 $(call cmd_and_fixdep,rustc_o_rs) 264 $(call cmd,gen_objtooldep) 265endef 266 267$(obj)/%.o: $(obj)/%.rs FORCE 268 +$(call if_changed_rule,rustc_o_rs) 269 270quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 271 cmd_rustc_rsi_rs = \ 272 $(rust_common_cmd) -Zunpretty=expanded $< >$@; \ 273 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@ 274 275$(obj)/%.rsi: $(obj)/%.rs FORCE 276 +$(call if_changed_dep,rustc_rsi_rs) 277 278quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 279 cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $< 280 281$(obj)/%.s: $(obj)/%.rs FORCE 282 +$(call if_changed_dep,rustc_s_rs) 283 284quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 285 cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $< 286 287$(obj)/%.ll: $(obj)/%.rs FORCE 288 +$(call if_changed_dep,rustc_ll_rs) 289 290quiet_cmd_rustc_rs_rs_S = RSCPP $(quiet_modtag) $@ 291 cmd_rustc_rs_rs_S = $(CPP) $(c_flags) -xc -C -P $< | sed '1,/^\/\/ Cut here.$$/d' >$@ 292 293$(obj)/%.rs: $(obj)/%.rs.S FORCE 294 +$(call if_changed_dep,rustc_rs_rs_S) 295 296# Compile assembler sources (.S) 297# --------------------------------------------------------------------------- 298 299# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 300# or a file that it includes, in order to get versioned symbols. We build a 301# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 302# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 303# 304# This is convoluted. The .S file must first be preprocessed to run guards and 305# expand names, then the resulting exports must be constructed into plain 306# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 307# to make the genksyms input or compiled into an object for gendwarfksyms. 308# 309# These mirror gensymtypes_c and co above, keep them in synch. 310getasmexports = \ 311 { echo "\#include <linux/kernel.h>" ; \ 312 echo "\#include <linux/string.h>" ; \ 313 echo "\#include <asm/asm-prototypes.h>" ; \ 314 $(call getexportsymbols,EXPORT_SYMBOL(\1);) ; } 315 316ifdef CONFIG_GENDWARFKSYMS 317cmd_gensymtypes_S = \ 318 $(getasmexports) | \ 319 $(CC) $(c_flags) -c -o $(@:.o=.gendwarfksyms.o) -xc -; \ 320 $(call getexportsymbols,\1) | \ 321 $(gendwarfksyms) $(@:.o=.gendwarfksyms.o) 322else 323cmd_gensymtypes_S = \ 324 $(getasmexports) | \ 325 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) 326endif # CONFIG_GENDWARFKSYMS 327 328quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 329cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 330 331$(obj)/%.s: $(obj)/%.S FORCE 332 $(call if_changed_dep,cpp_s_S) 333 334ifdef CONFIG_ASM_MODVERSIONS 335 336# versioning matches the C process described above, with difference that 337# we parse asm-prototypes.h C header to get function definitions. 338 339cmd_gen_symversions_S = $(call gen_symversions,S) 340 341endif 342 343$(obj)/%.o: $(obj)/%.S FORCE 344 $(call if_changed_rule,as_o_S) 345 346targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 347targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 348targets += $(lib-y) $(always-y) 349 350# Linker scripts preprocessor (.lds.S -> .lds) 351# --------------------------------------------------------------------------- 352quiet_cmd_cpp_lds_S = LDS $@ 353 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 354 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 355 356$(obj)/%.lds: $(src)/%.lds.S FORCE 357 $(call if_changed_dep,cpp_lds_S) 358 359# ASN.1 grammar 360# --------------------------------------------------------------------------- 361quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 362 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 363 $(basename $@).c $(basename $@).h 364 365$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 366 $(call cmd,asn1_compiler) 367 368# Build the compiled-in targets 369# --------------------------------------------------------------------------- 370 371# To build objects in subdirs, we need to descend into the directories 372$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 373$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 374 375# 376# Rule to compile a set of .o files into one .a file (without symbol table) 377# 378# To make this rule robust against "Argument list too long" error, 379# remove $(obj)/ prefix, and restore it by a shell command. 380 381quiet_cmd_ar_builtin = AR $@ 382 cmd_ar_builtin = rm -f $@; \ 383 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \ 384 $(AR) cDPrST $@ 385 386$(obj)/built-in.a: $(real-obj-y) FORCE 387 $(call if_changed,ar_builtin) 388 389# This is a list of build artifacts from the current Makefile and its 390# sub-directories. The timestamp should be updated when any of the member files. 391 392cmd_gen_order = { $(foreach m, $(real-prereqs), \ 393 $(if $(filter %/$(notdir $@), $m), cat $m, echo $m);) :; } \ 394 > $@ 395 396$(obj)/modules.order: $(obj-m) FORCE 397 $(call if_changed,gen_order) 398 399# 400# Rule to compile a set of .o files into one .a file (with symbol table) 401# 402 403$(obj)/lib.a: $(lib-y) FORCE 404 $(call if_changed,ar) 405 406quiet_cmd_ld_multi_m = LD [M] $@ 407 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$< $(cmd_objtool) 408 409define rule_ld_multi_m 410 $(call cmd_and_savecmd,ld_multi_m) 411 $(call cmd,gen_objtooldep) 412endef 413 414$(multi-obj-m): private objtool-enabled := $(delay-objtool) 415$(multi-obj-m): private part-of-module := y 416$(multi-obj-m): %.o: %.mod FORCE 417 $(call if_changed_rule,ld_multi_m) 418$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 419 420# Add intermediate targets: 421# When building objects with specific suffix patterns, add intermediate 422# targets that the final targets are derived from. 423intermediate_targets = $(foreach sfx, $(2), \ 424 $(patsubst %$(strip $(1)),%$(sfx), \ 425 $(filter %$(strip $(1)), $(targets)))) 426# %.asn1.o <- %.asn1.[ch] <- %.asn1 427targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) 428 429# Include additional build rules when necessary 430# --------------------------------------------------------------------------- 431 432# $(sort ...) is used here to remove duplicated words and excessive spaces. 433hostprogs := $(sort $(hostprogs)) 434ifneq ($(hostprogs),) 435include $(srctree)/scripts/Makefile.host 436endif 437 438# $(sort ...) is used here to remove duplicated words and excessive spaces. 439userprogs := $(sort $(userprogs)) 440ifneq ($(userprogs),) 441include $(srctree)/scripts/Makefile.userprogs 442endif 443 444ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets)),) 445include $(srctree)/scripts/Makefile.dtbs 446endif 447 448# Build 449# --------------------------------------------------------------------------- 450 451$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 452 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 453 $(subdir-ym) $(always-y) 454 @: 455 456# Single targets 457# --------------------------------------------------------------------------- 458 459single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d)) 460single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS)) 461 462$(single-subdir-goals): $(single-subdirs) 463 @: 464 465# Descending 466# --------------------------------------------------------------------------- 467 468PHONY += $(subdir-ym) 469$(subdir-ym): 470 $(Q)$(MAKE) $(build)=$@ \ 471 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 472 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \ 473 $(filter $@/%, $(single-subdir-goals)) 474 475# Add FORCE to the prerequisites of a target to force it to be always rebuilt. 476# --------------------------------------------------------------------------- 477 478PHONY += FORCE 479 480FORCE: 481 482targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS)) 483targets := $(filter-out $(PHONY), $(targets)) 484 485# Read all saved command lines and dependencies for the $(targets) we 486# may be building above, using $(if_changed{,_dep}). As an 487# optimization, we don't need to read them if the target does not 488# exist, we will rebuild anyway in that case. 489 490existing-targets := $(wildcard $(sort $(targets))) 491 492-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 493 494# Create directories for object files if they do not exist 495obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 496# If targets exist, their directories apparently exist. Skip mkdir. 497existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 498obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 499ifneq ($(obj-dirs),) 500$(shell mkdir -p $(obj-dirs)) 501endif 502 503.PHONY: $(PHONY) 504