1# SPDX-License-Identifier: GPL-2.0 2# ========================================================================== 3# Building 4# ========================================================================== 5 6src := $(obj) 7 8PHONY := __build 9__build: 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 := 29cppflags-y := 30ldflags-y := 31 32subdir-asflags-y := 33subdir-ccflags-y := 34 35# Read auto.conf if it exists, otherwise ignore 36-include include/config/auto.conf 37 38include $(srctree)/scripts/Kbuild.include 39include $(srctree)/scripts/Makefile.compiler 40 41# The filename Kbuild has precedence over Makefile 42kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 43include $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile) 44 45include $(srctree)/scripts/Makefile.lib 46 47# Do not include hostprogs rules unless needed. 48# $(sort ...) is used here to remove duplicated words and excessive spaces. 49hostprogs := $(sort $(hostprogs)) 50ifneq ($(hostprogs),) 51include $(srctree)/scripts/Makefile.host 52endif 53 54# Do not include userprogs rules unless needed. 55# $(sort ...) is used here to remove duplicated words and excessive spaces. 56userprogs := $(sort $(userprogs)) 57ifneq ($(userprogs),) 58include $(srctree)/scripts/Makefile.userprogs 59endif 60 61ifndef obj 62$(warning kbuild: Makefile.build is included improperly) 63endif 64 65ifeq ($(need-modorder),) 66ifneq ($(obj-m),) 67$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 68$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 69endif 70endif 71 72# =========================================================================== 73 74# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...) 75subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y))) 76subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) 77 78targets-for-builtin := $(extra-y) 79 80ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 81targets-for-builtin += $(obj)/lib.a 82endif 83 84ifdef need-builtin 85targets-for-builtin += $(obj)/built-in.a 86endif 87 88targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \ 89 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) 90 91ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) 92targets-for-modules += $(patsubst %.o, %.prelink.o, $(filter %.o, $(obj-m))) 93endif 94 95ifdef need-modorder 96targets-for-modules += $(obj)/modules.order 97endif 98 99targets += $(targets-for-builtin) $(targets-for-modules) 100 101# Linus' kernel sanity checking tool 102ifeq ($(KBUILD_CHECKSRC),1) 103 quiet_cmd_checksrc = CHECK $< 104 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 105else ifeq ($(KBUILD_CHECKSRC),2) 106 quiet_cmd_force_checksrc = CHECK $< 107 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 108endif 109 110ifneq ($(KBUILD_EXTRA_WARN),) 111 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 112endif 113 114# Compile C sources (.c) 115# --------------------------------------------------------------------------- 116 117quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 118 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< 119 120$(obj)/%.s: $(src)/%.c FORCE 121 $(call if_changed_dep,cc_s_c) 122 123quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 124cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 125 126$(obj)/%.i: $(src)/%.c FORCE 127 $(call if_changed_dep,cpp_i_c) 128 129genksyms = scripts/genksyms/genksyms \ 130 $(if $(1), -T $(2)) \ 131 $(if $(KBUILD_PRESERVE), -p) \ 132 -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null) 133 134# These mirror gensymtypes_S and co below, keep them in synch. 135cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) 136 137quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 138 cmd_cc_symtypes_c = $(call cmd_gensymtypes_c,true,$@) >/dev/null 139 140$(obj)/%.symtypes : $(src)/%.c FORCE 141 $(call cmd,cc_symtypes_c) 142 143# LLVM assembly 144# Generate .ll files from .c 145quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 146 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< 147 148$(obj)/%.ll: $(src)/%.c FORCE 149 $(call if_changed_dep,cc_ll_c) 150 151# C (.c) files 152# The C file is compiled and updated dependency information is generated. 153# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 154 155quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 156 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< $(cmd_objtool) 157 158ifdef CONFIG_MODVERSIONS 159# When module versioning is enabled the following steps are executed: 160# o compile a <file>.o from <file>.c 161# o if <file>.o doesn't contain a __ksymtab version, i.e. does 162# not export symbols, it's done. 163# o otherwise, we calculate symbol versions using the good old 164# genksyms on the preprocessed source and dump them into the .cmd file. 165# o modpost will extract versions from that file and create *.c files that will 166# be compiled and linked to the kernel and/or modules. 167 168gen_symversions = \ 169 if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ 170 $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 171 >> $(dot-target).cmd; \ 172 fi 173 174cmd_gen_symversions_c = $(call gen_symversions,c) 175 176endif 177 178ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 179# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 180ifdef BUILD_C_RECORDMCOUNT 181ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 182 RECORDMCOUNT_FLAGS = -w 183endif 184# Due to recursion, we must skip empty.o. 185# The empty.o file is created in the make process in order to determine 186# the target endianness and word size. It is made before all other C 187# files, including recordmcount. 188sub_cmd_record_mcount = \ 189 if [ $(@) != "scripts/mod/empty.o" ]; then \ 190 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 191 fi; 192recordmcount_source := $(srctree)/scripts/recordmcount.c \ 193 $(srctree)/scripts/recordmcount.h 194else 195sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 196 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 197 "$(if $(CONFIG_64BIT),64,32)" \ 198 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 199 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 200 "$(if $(part-of-module),1,0)" "$(@)"; 201recordmcount_source := $(srctree)/scripts/recordmcount.pl 202endif # BUILD_C_RECORDMCOUNT 203cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 204 $(sub_cmd_record_mcount)) 205endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT 206 207ifdef CONFIG_OBJTOOL 208 209objtool := $(objtree)/tools/objtool/objtool 210 211objtool_args = \ 212 $(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label) \ 213 $(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \ 214 $(if $(CONFIG_X86_KERNEL_IBT), --ibt) \ 215 $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \ 216 $(if $(CONFIG_UNWINDER_ORC), --orc) \ 217 $(if $(CONFIG_RETPOLINE), --retpoline) \ 218 $(if $(CONFIG_SLS), --sls) \ 219 $(if $(CONFIG_STACK_VALIDATION), --stackval) \ 220 $(if $(CONFIG_HAVE_STATIC_CALL_INLINE), --static-call) \ 221 --uaccess \ 222 $(if $(linked-object), --link) \ 223 $(if $(part-of-module), --module) \ 224 $(if $(CONFIG_GCOV_KERNEL), --no-unreachable) 225 226cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@) 227cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd) 228 229endif # CONFIG_OBJTOOL 230 231ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) 232 233# Skip objtool for LLVM bitcode 234$(obj)/%.o: objtool-enabled := 235 236else 237 238# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 239# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 240# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 241 242$(obj)/%.o: objtool-enabled = $(if $(filter-out y%, \ 243 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y) 244 245endif 246 247ifdef CONFIG_TRIM_UNUSED_KSYMS 248cmd_gen_ksymdeps = \ 249 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 250endif 251 252define rule_cc_o_c 253 $(call cmd_and_fixdep,cc_o_c) 254 $(call cmd,gen_ksymdeps) 255 $(call cmd,checksrc) 256 $(call cmd,checkdoc) 257 $(call cmd,gen_objtooldep) 258 $(call cmd,gen_symversions_c) 259 $(call cmd,record_mcount) 260endef 261 262define rule_as_o_S 263 $(call cmd_and_fixdep,as_o_S) 264 $(call cmd,gen_ksymdeps) 265 $(call cmd,gen_objtooldep) 266 $(call cmd,gen_symversions_S) 267endef 268 269# Built-in and composite module parts 270$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE 271 $(call if_changed_rule,cc_o_c) 272 $(call cmd,force_checksrc) 273 274ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) 275# Module .o files may contain LLVM bitcode, compile them into native code 276# before ELF processing 277quiet_cmd_cc_prelink_modules = LD [M] $@ 278 cmd_cc_prelink_modules = \ 279 $(LD) $(ld_flags) -r -o $@ \ 280 --whole-archive $(filter-out FORCE,$^) \ 281 $(cmd_objtool) 282 283# objtool was skipped for LLVM bitcode, run it now that we have compiled 284# modules into native code 285$(obj)/%.prelink.o: objtool-enabled = y 286$(obj)/%.prelink.o: part-of-module := y 287$(obj)/%.prelink.o: linked-object := y 288 289$(obj)/%.prelink.o: $(obj)/%.o FORCE 290 $(call if_changed,cc_prelink_modules) 291endif 292 293cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \ 294 $(AWK) -v RS='( |\n)' '!x[$$0]++' > $@ 295 296$(obj)/%.mod: FORCE 297 $(call if_changed,mod) 298 299# List module undefined symbols 300cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@ 301 302$(obj)/%.usyms: $(obj)/%$(mod-prelink-ext).o FORCE 303 $(call if_changed,undefined_syms) 304 305quiet_cmd_cc_lst_c = MKLST $@ 306 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 307 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 308 System.map $(OBJDUMP) > $@ 309 310$(obj)/%.lst: $(src)/%.c FORCE 311 $(call if_changed_dep,cc_lst_c) 312 313# Compile assembler sources (.S) 314# --------------------------------------------------------------------------- 315 316# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 317# or a file that it includes, in order to get versioned symbols. We build a 318# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 319# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 320# 321# This is convoluted. The .S file must first be preprocessed to run guards and 322# expand names, then the resulting exports must be constructed into plain 323# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 324# to make the genksyms input. 325# 326# These mirror gensymtypes_c and co above, keep them in synch. 327cmd_gensymtypes_S = \ 328 { echo "\#include <linux/kernel.h>" ; \ 329 echo "\#include <asm/asm-prototypes.h>" ; \ 330 $(CPP) $(a_flags) $< | \ 331 grep "\<___EXPORT_SYMBOL\>" | \ 332 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 333 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) 334 335quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 336 cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null 337 338$(obj)/%.symtypes : $(src)/%.S FORCE 339 $(call cmd,cc_symtypes_S) 340 341 342quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 343cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 344 345$(obj)/%.s: $(src)/%.S FORCE 346 $(call if_changed_dep,cpp_s_S) 347 348quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 349 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool) 350 351ifdef CONFIG_ASM_MODVERSIONS 352 353# versioning matches the C process described above, with difference that 354# we parse asm-prototypes.h C header to get function definitions. 355 356cmd_gen_symversions_S = $(call gen_symversions,S) 357 358endif 359 360$(obj)/%.o: $(src)/%.S FORCE 361 $(call if_changed_rule,as_o_S) 362 363targets += $(filter-out $(subdir-builtin), $(real-obj-y)) 364targets += $(filter-out $(subdir-modorder), $(real-obj-m)) 365targets += $(real-dtb-y) $(lib-y) $(always-y) $(MAKECMDGOALS) 366 367# Linker scripts preprocessor (.lds.S -> .lds) 368# --------------------------------------------------------------------------- 369quiet_cmd_cpp_lds_S = LDS $@ 370 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 371 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 372 373$(obj)/%.lds: $(src)/%.lds.S FORCE 374 $(call if_changed_dep,cpp_lds_S) 375 376# ASN.1 grammar 377# --------------------------------------------------------------------------- 378quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 379 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 380 $(basename $@).c $(basename $@).h 381 382$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 383 $(call cmd,asn1_compiler) 384 385# Build the compiled-in targets 386# --------------------------------------------------------------------------- 387 388# To build objects in subdirs, we need to descend into the directories 389$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; 390$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; 391 392# 393# Rule to compile a set of .o files into one .a file (without symbol table) 394# 395 396quiet_cmd_ar_builtin = AR $@ 397 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) 398 399$(obj)/built-in.a: $(real-obj-y) FORCE 400 $(call if_changed,ar_builtin) 401 402# 403# Rule to create modules.order file 404# 405# Create commands to either record .ko file or cat modules.order from 406# a subdirectory 407# Add $(obj-m) as the prerequisite to avoid updating the timestamp of 408# modules.order unless contained modules are updated. 409 410cmd_modules_order = { $(foreach m, $(real-prereqs), \ 411 $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \ 412 | $(AWK) '!x[$$0]++' - > $@ 413 414$(obj)/modules.order: $(obj-m) FORCE 415 $(call if_changed,modules_order) 416 417# 418# Rule to compile a set of .o files into one .a file (with symbol table) 419# 420 421$(obj)/lib.a: $(lib-y) FORCE 422 $(call if_changed,ar) 423 424ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) 425quiet_cmd_link_multi-m = AR [M] $@ 426cmd_link_multi-m = \ 427 rm -f $@; \ 428 $(AR) cDPrsT $@ @$(patsubst %.o,%.mod,$@) 429else 430quiet_cmd_link_multi-m = LD [M] $@ 431 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) 432endif 433 434$(multi-obj-m): %.o: %.mod FORCE 435 $(call if_changed,link_multi-m) 436$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) 437 438targets := $(filter-out $(PHONY), $(targets)) 439 440# Add intermediate targets: 441# When building objects with specific suffix patterns, add intermediate 442# targets that the final targets are derived from. 443intermediate_targets = $(foreach sfx, $(2), \ 444 $(patsubst %$(strip $(1)),%$(sfx), \ 445 $(filter %$(strip $(1)), $(targets)))) 446# %.asn1.o <- %.asn1.[ch] <- %.asn1 447# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 448# %.lex.o <- %.lex.c <- %.l 449# %.tab.o <- %.tab.[ch] <- %.y 450targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 451 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 452 $(call intermediate_targets, .lex.o, .lex.c) \ 453 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 454 455# Build 456# --------------------------------------------------------------------------- 457 458ifdef single-build 459 460KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS)) 461 462curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ 463 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) 464 465# Handle single targets without any rule: show "Nothing to be done for ..." or 466# "No rule to make target ..." depending on whether the target exists. 467unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ 468 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS))) 469 470single-subdirs := $(foreach d, $(subdir-ym), \ 471 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d))) 472 473__build: $(curdir-single) $(single-subdirs) 474ifneq ($(unknown-single),) 475 $(Q)$(MAKE) -f /dev/null $(unknown-single) 476endif 477 @: 478 479ifeq ($(curdir-single),) 480# Nothing to do in this directory. Do not include any .*.cmd file for speed-up 481targets := 482else 483targets += $(curdir-single) 484endif 485 486else 487 488__build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ 489 $(if $(KBUILD_MODULES), $(targets-for-modules)) \ 490 $(subdir-ym) $(always-y) 491 @: 492 493endif 494 495# Descending 496# --------------------------------------------------------------------------- 497 498PHONY += $(subdir-ym) 499$(subdir-ym): 500 $(Q)$(MAKE) $(build)=$@ \ 501 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ 502 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \ 503 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) 504 505# Add FORCE to the prequisites of a target to force it to be always rebuilt. 506# --------------------------------------------------------------------------- 507 508PHONY += FORCE 509 510FORCE: 511 512# Read all saved command lines and dependencies for the $(targets) we 513# may be building above, using $(if_changed{,_dep}). As an 514# optimization, we don't need to read them if the target does not 515# exist, we will rebuild anyway in that case. 516 517existing-targets := $(wildcard $(sort $(targets))) 518 519-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 520 521# Create directories for object files if they do not exist 522obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets)))) 523# If targets exist, their directories apparently exist. Skip mkdir. 524existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 525obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 526ifneq ($(obj-dirs),) 527$(shell mkdir -p $(obj-dirs)) 528endif 529 530.PHONY: $(PHONY) 531