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