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 110getexportsymbols = $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/$(1)/p' 111 112gendwarfksyms = $(objtree)/scripts/gendwarfksyms/gendwarfksyms \ 113 $(if $(KBUILD_SYMTYPES), --symtypes $(@:.o=.symtypes)) \ 114 $(if $(KBUILD_GENDWARFKSYMS_STABLE), --stable) 115 116genksyms = $(objtree)/scripts/genksyms/genksyms \ 117 $(if $(KBUILD_SYMTYPES), -T $(@:.o=.symtypes)) \ 118 $(if $(KBUILD_PRESERVE), -p) \ 119 $(addprefix -r , $(wildcard $(@:.o=.symref))) 120 121# These mirror gensymtypes_S and co below, keep them in synch. 122ifdef CONFIG_GENDWARFKSYMS 123cmd_gensymtypes_c = $(if $(skip_gendwarfksyms),, \ 124 $(call getexportsymbols,\1) | $(gendwarfksyms) $@) 125else 126cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) 127endif # CONFIG_GENDWARFKSYMS 128 129# LLVM assembly 130# Generate .ll files from .c 131quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 132 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $< 133 134$(obj)/%.ll: $(obj)/%.c FORCE 135 $(call if_changed_dep,cc_ll_c) 136 137# C (.c) files 138# The C file is compiled and updated dependency information is generated. 139# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 140 141is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) 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: $(modname-multi))) 201endif 202 203# Built-in and composite module parts 204$(obj)/%.o: $(obj)/%.c $(recordmcount_source) FORCE 205 $(call if_changed_rule,cc_o_c) 206 $(call cmd,force_checksrc) 207 208# To make this rule robust against "Argument list too long" error, 209# ensure to add $(obj)/ prefix by a shell command. 210cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ 211 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ 212 213$(obj)/%.mod: FORCE 214 $(call if_changed,mod) 215 216quiet_cmd_cc_lst_c = MKLST $@ 217 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 218 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 219 System.map $(OBJDUMP) > $@ 220 221$(obj)/%.lst: $(obj)/%.c FORCE 222 $(call if_changed_dep,cc_lst_c) 223 224# Compile Rust sources (.rs) 225# --------------------------------------------------------------------------- 226 227rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons 228 229# `--out-dir` is required to avoid temporaries being created by `rustc` in the 230# current working directory, which may be not accessible in the out-of-tree 231# modules case. 232rust_common_cmd = \ 233 OBJTREE=$(abspath $(objtree)) \ 234 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ 235 -Zallow-features=$(rust_allowed_features) \ 236 -Zcrate-attr=no_std \ 237 -Zcrate-attr='feature($(rust_allowed_features))' \ 238 -Zunstable-options --extern kernel \ 239 --crate-type rlib -L $(objtree)/rust/ \ 240 --crate-name $(basename $(notdir $@)) \ 241 --sysroot=/dev/null \ 242 --out-dir $(dir $@) --emit=dep-info=$(depfile) 243 244# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit 245# will be used. We explicitly request `-Ccodegen-units=1` in any case, and 246# the compiler shows a warning if it is not 1. However, if we ever stop 247# requesting it explicitly and we start using some other `--emit` that does not 248# imply it (and for which codegen is performed), then we would be out of sync, 249# i.e. the outputs we would get for the different single targets (e.g. `.ll`) 250# would not match each other. 251 252quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 253 cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< $(cmd_objtool) 254 255define rule_rustc_o_rs 256 $(call cmd_and_fixdep,rustc_o_rs) 257 $(call cmd,gen_objtooldep) 258endef 259 260$(obj)/%.o: $(obj)/%.rs FORCE 261 +$(call if_changed_rule,rustc_o_rs) 262 263quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 264 cmd_rustc_rsi_rs = \ 265 $(rust_common_cmd) -Zunpretty=expanded $< >$@; \ 266 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@ 267 268$(obj)/%.rsi: $(obj)/%.rs FORCE 269 +$(call if_changed_dep,rustc_rsi_rs) 270 271quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 272 cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $< 273 274$(obj)/%.s: $(obj)/%.rs FORCE 275 +$(call if_changed_dep,rustc_s_rs) 276 277quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ 278 cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $< 279 280$(obj)/%.ll: $(obj)/%.rs FORCE 281 +$(call if_changed_dep,rustc_ll_rs) 282 283quiet_cmd_rustc_rs_rs_S = RSCPP $(quiet_modtag) $@ 284 cmd_rustc_rs_rs_S = $(CPP) $(c_flags) -xc -C -P $< | sed '1,/^\/\/ Cut here.$$/d' >$@ 285 286$(obj)/%.rs: $(obj)/%.rs.S FORCE 287 +$(call if_changed_dep,rustc_rs_rs_S) 288 289# Compile assembler sources (.S) 290# --------------------------------------------------------------------------- 291 292# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 293# or a file that it includes, in order to get versioned symbols. We build a 294# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 295# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 296# 297# This is convoluted. The .S file must first be preprocessed to run guards and 298# expand names, then the resulting exports must be constructed into plain 299# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 300# to make the genksyms input or compiled into an object for gendwarfksyms. 301# 302# These mirror gensymtypes_c and co above, keep them in synch. 303getasmexports = \ 304 { echo "\#include <linux/kernel.h>" ; \ 305 echo "\#include <linux/string.h>" ; \ 306 echo "\#include <asm/asm-prototypes.h>" ; \ 307 $(call getexportsymbols,EXPORT_SYMBOL(\1);) ; } 308 309ifdef CONFIG_GENDWARFKSYMS 310cmd_gensymtypes_S = \ 311 $(getasmexports) | \ 312 $(CC) $(c_flags) -c -o $(@:.o=.gendwarfksyms.o) -xc -; \ 313 $(call getexportsymbols,\1) | \ 314 $(gendwarfksyms) $(@:.o=.gendwarfksyms.o) 315else 316cmd_gensymtypes_S = \ 317 $(getasmexports) | \ 318 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) 319endif # CONFIG_GENDWARFKSYMS 320 321quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 322cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 323 324$(obj)/%.s: $(obj)/%.S FORCE 325 $(call if_changed_dep,cpp_s_S) 326 327ifdef CONFIG_ASM_MODVERSIONS 328 329# versioning matches the C process described above, with difference that 330# we parse asm-prototypes.h C header to get function definitions. 331 332cmd_gen_symversions_S = $(call gen_symversions,S) 333 334endif 335 336$(obj)/%.o: $(obj)/%.S FORCE 337 $(call if_changed_rule,as_o_S) 338 339targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 340targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 341targets += $(lib-y) $(always-y) 342 343# Linker scripts preprocessor (.lds.S -> .lds) 344# --------------------------------------------------------------------------- 345quiet_cmd_cpp_lds_S = LDS $@ 346 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 347 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 348 349$(obj)/%.lds: $(src)/%.lds.S FORCE 350 $(call if_changed_dep,cpp_lds_S) 351 352# ASN.1 grammar 353# --------------------------------------------------------------------------- 354quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 355 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 356 $(basename $@).c $(basename $@).h 357 358$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 359 $(call cmd,asn1_compiler) 360 361# Build the compiled-in targets 362# --------------------------------------------------------------------------- 363 364# To build objects in subdirs, we need to descend into the directories 365$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 366$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 367 368# 369# Rule to compile a set of .o files into one .a file (without symbol table) 370# 371# To make this rule robust against "Argument list too long" error, 372# remove $(obj)/ prefix, and restore it by a shell command. 373 374quiet_cmd_ar_builtin = AR $@ 375 cmd_ar_builtin = rm -f $@; \ 376 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \ 377 $(AR) cDPrST $@ 378 379$(obj)/built-in.a: $(real-obj-y) FORCE 380 $(call if_changed,ar_builtin) 381 382# This is a list of build artifacts from the current Makefile and its 383# sub-directories. The timestamp should be updated when any of the member files. 384 385cmd_gen_order = { $(foreach m, $(real-prereqs), \ 386 $(if $(filter %/$(notdir $@), $m), cat $m, echo $m);) :; } \ 387 > $@ 388 389$(obj)/modules.order: $(obj-m) FORCE 390 $(call if_changed,gen_order) 391 392# 393# Rule to compile a set of .o files into one .a file (with symbol table) 394# 395 396$(obj)/lib.a: $(lib-y) FORCE 397 $(call if_changed,ar) 398 399quiet_cmd_ld_multi_m = LD [M] $@ 400 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$< $(cmd_objtool) 401 402define rule_ld_multi_m 403 $(call cmd_and_savecmd,ld_multi_m) 404 $(call cmd,gen_objtooldep) 405endef 406 407$(multi-obj-m): private objtool-enabled := $(delay-objtool) 408$(multi-obj-m): private part-of-module := y 409$(multi-obj-m): %.o: %.mod FORCE 410 $(call if_changed_rule,ld_multi_m) 411$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 412 413# Add intermediate targets: 414# When building objects with specific suffix patterns, add intermediate 415# targets that the final targets are derived from. 416intermediate_targets = $(foreach sfx, $(2), \ 417 $(patsubst %$(strip $(1)),%$(sfx), \ 418 $(filter %$(strip $(1)), $(targets)))) 419# %.asn1.o <- %.asn1.[ch] <- %.asn1 420targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) 421 422# Include additional build rules when necessary 423# --------------------------------------------------------------------------- 424 425# $(sort ...) is used here to remove duplicated words and excessive spaces. 426hostprogs := $(sort $(hostprogs)) 427ifneq ($(hostprogs),) 428include $(srctree)/scripts/Makefile.host 429endif 430 431# $(sort ...) is used here to remove duplicated words and excessive spaces. 432userprogs := $(sort $(userprogs)) 433ifneq ($(userprogs),) 434include $(srctree)/scripts/Makefile.userprogs 435endif 436 437ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets)),) 438include $(srctree)/scripts/Makefile.dtbs 439endif 440 441# Build 442# --------------------------------------------------------------------------- 443 444$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 445 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 446 $(subdir-ym) $(always-y) 447 @: 448 449# Single targets 450# --------------------------------------------------------------------------- 451 452single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d)) 453single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS)) 454 455$(single-subdir-goals): $(single-subdirs) 456 @: 457 458# Descending 459# --------------------------------------------------------------------------- 460 461PHONY += $(subdir-ym) 462$(subdir-ym): 463 $(Q)$(MAKE) $(build)=$@ \ 464 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 465 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \ 466 $(filter $@/%, $(single-subdir-goals)) 467 468# Add FORCE to the prerequisites of a target to force it to be always rebuilt. 469# --------------------------------------------------------------------------- 470 471PHONY += FORCE 472 473FORCE: 474 475targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS)) 476targets := $(filter-out $(PHONY), $(targets)) 477 478# Read all saved command lines and dependencies for the $(targets) we 479# may be building above, using $(if_changed{,_dep}). As an 480# optimization, we don't need to read them if the target does not 481# exist, we will rebuild anyway in that case. 482 483existing-targets := $(wildcard $(sort $(targets))) 484 485-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 486 487# Create directories for object files if they do not exist 488obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 489# If targets exist, their directories apparently exist. Skip mkdir. 490existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 491obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 492ifneq ($(obj-dirs),) 493$(shell mkdir -p $(obj-dirs)) 494endif 495 496.PHONY: $(PHONY) 497