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 := 19always-y := 20always-m := 21targets := 22subdir-y := 23subdir-m := 24EXTRA_AFLAGS := 25EXTRA_CFLAGS := 26EXTRA_CPPFLAGS := 27EXTRA_LDFLAGS := 28asflags-y := 29ccflags-y := 30cppflags-y := 31ldflags-y := 32 33subdir-asflags-y := 34subdir-ccflags-y := 35 36# Read auto.conf if it exists, otherwise ignore 37-include include/config/auto.conf 38 39include scripts/Kbuild.include 40 41# The filename Kbuild has precedence over Makefile 42kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 43kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) 44include $(kbuild-file) 45 46include scripts/Makefile.lib 47 48# Do not include host rules unless needed 49ifneq ($(hostprogs)$(hostcxxlibs-y)$(hostcxxlibs-m),) 50include scripts/Makefile.host 51endif 52 53# Do not include userprogs rules unless needed. 54userprogs := $(sort $(userprogs)) 55ifneq ($(userprogs),) 56include scripts/Makefile.userprogs 57endif 58 59ifndef obj 60$(warning kbuild: Makefile.build is included improperly) 61endif 62 63ifeq ($(need-modorder),) 64ifneq ($(obj-m),) 65$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 66$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 67endif 68endif 69 70# =========================================================================== 71 72ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 73lib-target := $(obj)/lib.a 74endif 75 76ifdef need-builtin 77builtin-target := $(obj)/built-in.a 78endif 79 80ifeq ($(CONFIG_MODULES)$(need-modorder),y1) 81modorder-target := $(obj)/modules.order 82endif 83 84mod-targets := $(patsubst %.o, %.mod, $(obj-m)) 85 86# Linus' kernel sanity checking tool 87ifeq ($(KBUILD_CHECKSRC),1) 88 quiet_cmd_checksrc = CHECK $< 89 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 90else ifeq ($(KBUILD_CHECKSRC),2) 91 quiet_cmd_force_checksrc = CHECK $< 92 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 93endif 94 95ifneq ($(KBUILD_EXTRA_WARN),) 96 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 97endif 98 99# Compile C sources (.c) 100# --------------------------------------------------------------------------- 101 102quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 103 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $< 104 105$(obj)/%.s: $(src)/%.c FORCE 106 $(call if_changed_dep,cc_s_c) 107 108quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 109cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 110 111$(obj)/%.i: $(src)/%.c FORCE 112 $(call if_changed_dep,cpp_i_c) 113 114# These mirror gensymtypes_S and co below, keep them in synch. 115cmd_gensymtypes_c = \ 116 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 117 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 118 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 119 $(if $(KBUILD_PRESERVE),-p) \ 120 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 121 122quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 123cmd_cc_symtypes_c = \ 124 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ 125 test -s $@ || rm -f $@ 126 127$(obj)/%.symtypes : $(src)/%.c FORCE 128 $(call cmd,cc_symtypes_c) 129 130# LLVM assembly 131# Generate .ll files from .c 132quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 133 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< 134 135$(obj)/%.ll: $(src)/%.c FORCE 136 $(call if_changed_dep,cc_ll_c) 137 138# C (.c) files 139# The C file is compiled and updated dependency information is generated. 140# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 141 142quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 143 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 144 145ifdef CONFIG_MODVERSIONS 146# When module versioning is enabled the following steps are executed: 147# o compile a <file>.o from <file>.c 148# o if <file>.o doesn't contain a __ksymtab version, i.e. does 149# not export symbols, it's done. 150# o otherwise, we calculate symbol versions using the good old 151# genksyms on the preprocessed source and postprocess them in a way 152# that they are usable as a linker script 153# o generate .tmp_<file>.o from <file>.o using the linker to 154# replace the unresolved symbols __crc_exported_symbol with 155# the actual value of the checksum generated by genksyms 156# o remove .tmp_<file>.o to <file>.o 157 158cmd_modversions_c = \ 159 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 160 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 161 > $(@D)/.tmp_$(@F:.o=.ver); \ 162 \ 163 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 164 -T $(@D)/.tmp_$(@F:.o=.ver); \ 165 mv -f $(@D)/.tmp_$(@F) $@; \ 166 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 167 fi 168endif 169 170ifdef CONFIG_FTRACE_MCOUNT_RECORD 171ifndef CC_USING_RECORD_MCOUNT 172# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 173ifdef BUILD_C_RECORDMCOUNT 174ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 175 RECORDMCOUNT_FLAGS = -w 176endif 177# Due to recursion, we must skip empty.o. 178# The empty.o file is created in the make process in order to determine 179# the target endianness and word size. It is made before all other C 180# files, including recordmcount. 181sub_cmd_record_mcount = \ 182 if [ $(@) != "scripts/mod/empty.o" ]; then \ 183 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 184 fi; 185recordmcount_source := $(srctree)/scripts/recordmcount.c \ 186 $(srctree)/scripts/recordmcount.h 187else 188sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 189 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 190 "$(if $(CONFIG_64BIT),64,32)" \ 191 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 192 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 193 "$(if $(part-of-module),1,0)" "$(@)"; 194recordmcount_source := $(srctree)/scripts/recordmcount.pl 195endif # BUILD_C_RECORDMCOUNT 196cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 197 $(sub_cmd_record_mcount)) 198endif # CC_USING_RECORD_MCOUNT 199endif # CONFIG_FTRACE_MCOUNT_RECORD 200 201ifdef CONFIG_STACK_VALIDATION 202ifneq ($(SKIP_STACK_VALIDATION),1) 203 204__objtool_obj := $(objtree)/tools/objtool/objtool 205 206objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check) 207 208objtool_args += $(if $(part-of-module), --module,) 209 210ifndef CONFIG_FRAME_POINTER 211objtool_args += --no-fp 212endif 213ifdef CONFIG_GCOV_KERNEL 214objtool_args += --no-unreachable 215endif 216ifdef CONFIG_RETPOLINE 217 objtool_args += --retpoline 218endif 219ifdef CONFIG_X86_SMAP 220 objtool_args += --uaccess 221endif 222 223# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 224# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 225# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 226cmd_objtool = $(if $(patsubst y%,, \ 227 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 228 $(__objtool_obj) $(objtool_args) $@) 229objtool_obj = $(if $(patsubst y%,, \ 230 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 231 $(__objtool_obj)) 232 233endif # SKIP_STACK_VALIDATION 234endif # CONFIG_STACK_VALIDATION 235 236# Rebuild all objects when objtool changes, or is enabled/disabled. 237objtool_dep = $(objtool_obj) \ 238 $(wildcard include/config/orc/unwinder.h \ 239 include/config/stack/validation.h) 240 241ifdef CONFIG_TRIM_UNUSED_KSYMS 242cmd_gen_ksymdeps = \ 243 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 244endif 245 246define rule_cc_o_c 247 $(call cmd,checksrc) 248 $(call cmd_and_fixdep,cc_o_c) 249 $(call cmd,gen_ksymdeps) 250 $(call cmd,checkdoc) 251 $(call cmd,objtool) 252 $(call cmd,modversions_c) 253 $(call cmd,record_mcount) 254endef 255 256define rule_as_o_S 257 $(call cmd_and_fixdep,as_o_S) 258 $(call cmd,gen_ksymdeps) 259 $(call cmd,objtool) 260 $(call cmd,modversions_S) 261endef 262 263# List module undefined symbols (or empty line if not enabled) 264ifdef CONFIG_TRIM_UNUSED_KSYMS 265cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo 266else 267cmd_undef_syms = echo 268endif 269 270# Built-in and composite module parts 271$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE 272 $(call cmd,force_checksrc) 273 $(call if_changed_rule,cc_o_c) 274 275cmd_mod = { \ 276 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ 277 $(cmd_undef_syms); \ 278 } > $@ 279 280$(obj)/%.mod: $(obj)/%.o FORCE 281 $(call if_changed,mod) 282 283targets += $(mod-targets) 284 285quiet_cmd_cc_lst_c = MKLST $@ 286 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 287 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 288 System.map $(OBJDUMP) > $@ 289 290$(obj)/%.lst: $(src)/%.c FORCE 291 $(call if_changed_dep,cc_lst_c) 292 293# Compile assembler sources (.S) 294# --------------------------------------------------------------------------- 295 296# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 297# or a file that it includes, in order to get versioned symbols. We build a 298# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 299# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 300# 301# This is convoluted. The .S file must first be preprocessed to run guards and 302# expand names, then the resulting exports must be constructed into plain 303# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 304# to make the genksyms input. 305# 306# These mirror gensymtypes_c and co above, keep them in synch. 307cmd_gensymtypes_S = \ 308 { echo "\#include <linux/kernel.h>" ; \ 309 echo "\#include <asm/asm-prototypes.h>" ; \ 310 $(CPP) $(a_flags) $< | \ 311 grep "\<___EXPORT_SYMBOL\>" | \ 312 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 313 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 314 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 315 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 316 $(if $(KBUILD_PRESERVE),-p) \ 317 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 318 319quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 320cmd_cc_symtypes_S = \ 321 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 322 test -s $@ || rm -f $@ 323 324$(obj)/%.symtypes : $(src)/%.S FORCE 325 $(call cmd,cc_symtypes_S) 326 327 328quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 329cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 330 331$(obj)/%.s: $(src)/%.S FORCE 332 $(call if_changed_dep,cpp_s_S) 333 334quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 335 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 336 337ifdef CONFIG_ASM_MODVERSIONS 338 339# versioning matches the C process described above, with difference that 340# we parse asm-prototypes.h C header to get function definitions. 341 342cmd_modversions_S = \ 343 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 344 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 345 > $(@D)/.tmp_$(@F:.o=.ver); \ 346 \ 347 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 348 -T $(@D)/.tmp_$(@F:.o=.ver); \ 349 mv -f $(@D)/.tmp_$(@F) $@; \ 350 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 351 fi 352endif 353 354$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE 355 $(call if_changed_rule,as_o_S) 356 357targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y) 358targets += $(extra-y) $(always-y) $(MAKECMDGOALS) 359 360# Linker scripts preprocessor (.lds.S -> .lds) 361# --------------------------------------------------------------------------- 362quiet_cmd_cpp_lds_S = LDS $@ 363 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 364 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 365 366$(obj)/%.lds: $(src)/%.lds.S FORCE 367 $(call if_changed_dep,cpp_lds_S) 368 369# ASN.1 grammar 370# --------------------------------------------------------------------------- 371quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 372 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 373 $(basename $@).c $(basename $@).h 374 375$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 376 $(call cmd,asn1_compiler) 377 378# Build the compiled-in targets 379# --------------------------------------------------------------------------- 380 381# To build objects in subdirs, we need to descend into the directories 382$(obj)/%/built-in.a: $(obj)/% ; 383 384# 385# Rule to compile a set of .o files into one .a file (without symbol table) 386# 387ifdef builtin-target 388 389quiet_cmd_ar_builtin = AR $@ 390 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) 391 392$(builtin-target): $(real-obj-y) FORCE 393 $(call if_changed,ar_builtin) 394 395targets += $(builtin-target) 396endif # builtin-target 397 398# 399# Rule to create modules.order file 400# 401# Create commands to either record .ko file or cat modules.order from 402# a subdirectory 403$(modorder-target): $(subdir-ym) FORCE 404 $(Q){ $(foreach m, $(modorder), \ 405 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \ 406 | $(AWK) '!x[$$0]++' - > $@ 407 408# 409# Rule to compile a set of .o files into one .a file (with symbol table) 410# 411ifdef lib-target 412 413$(lib-target): $(lib-y) FORCE 414 $(call if_changed,ar) 415 416targets += $(lib-target) 417 418endif 419 420# NOTE: 421# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object 422# module is turned into a multi object module, $^ will contain header file 423# dependencies recorded in the .*.cmd file. 424quiet_cmd_link_multi-m = LD [M] $@ 425 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) 426 427$(multi-used-m): FORCE 428 $(call if_changed,link_multi-m) 429$(call multi_depend, $(multi-used-m), .o, -objs -y -m) 430 431targets += $(multi-used-m) 432targets := $(filter-out $(PHONY), $(targets)) 433 434# Add intermediate targets: 435# When building objects with specific suffix patterns, add intermediate 436# targets that the final targets are derived from. 437intermediate_targets = $(foreach sfx, $(2), \ 438 $(patsubst %$(strip $(1)),%$(sfx), \ 439 $(filter %$(strip $(1)), $(targets)))) 440# %.asn1.o <- %.asn1.[ch] <- %.asn1 441# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 442# %.lex.o <- %.lex.c <- %.l 443# %.tab.o <- %.tab.[ch] <- %.y 444targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 445 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 446 $(call intermediate_targets, .lex.o, .lex.c) \ 447 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 448 449# Build 450# --------------------------------------------------------------------------- 451 452ifdef single-build 453 454KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS)) 455 456curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ 457 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) 458 459# Handle single targets without any rule: show "Nothing to be done for ..." or 460# "No rule to make target ..." depending on whether the target exists. 461unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ 462 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS))) 463 464single-subdirs := $(foreach d, $(subdir-ym), \ 465 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d))) 466 467__build: $(curdir-single) $(single-subdirs) 468ifneq ($(unknown-single),) 469 $(Q)$(MAKE) -f /dev/null $(unknown-single) 470endif 471 @: 472 473ifeq ($(curdir-single),) 474# Nothing to do in this directory. Do not include any .*.cmd file for speed-up 475targets := 476else 477targets += $(curdir-single) 478endif 479 480else 481 482__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ 483 $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \ 484 $(subdir-ym) $(always-y) 485 @: 486 487endif 488 489# Descending 490# --------------------------------------------------------------------------- 491 492PHONY += $(subdir-ym) 493$(subdir-ym): 494 $(Q)$(MAKE) $(build)=$@ \ 495 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ 496 need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \ 497 need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1)) 498 499# Add FORCE to the prequisites of a target to force it to be always rebuilt. 500# --------------------------------------------------------------------------- 501 502PHONY += FORCE 503 504FORCE: 505 506# Read all saved command lines and dependencies for the $(targets) we 507# may be building above, using $(if_changed{,_dep}). As an 508# optimization, we don't need to read them if the target does not 509# exist, we will rebuild anyway in that case. 510 511existing-targets := $(wildcard $(sort $(targets))) 512 513-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 514 515ifdef building_out_of_srctree 516# Create directories for object files if they do not exist 517obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets)))) 518# If targets exist, their directories apparently exist. Skip mkdir. 519existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 520obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 521ifneq ($(obj-dirs),) 522$(shell mkdir -p $(obj-dirs)) 523endif 524endif 525 526.PHONY: $(PHONY) 527