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