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 := 19targets := 20subdir-y := 21subdir-m := 22EXTRA_AFLAGS := 23EXTRA_CFLAGS := 24EXTRA_CPPFLAGS := 25EXTRA_LDFLAGS := 26asflags-y := 27ccflags-y := 28cppflags-y := 29ldflags-y := 30 31subdir-asflags-y := 32subdir-ccflags-y := 33 34# Read auto.conf if it exists, otherwise ignore 35-include include/config/auto.conf 36 37include scripts/Kbuild.include 38 39# The filename Kbuild has precedence over Makefile 40kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 41kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) 42include $(kbuild-file) 43 44include scripts/Makefile.lib 45 46# Do not include host rules unless needed 47ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),) 48include scripts/Makefile.host 49endif 50 51ifndef obj 52$(warning kbuild: Makefile.build is included improperly) 53endif 54 55ifeq ($(MAKECMDGOALS)$(need-modorder),) 56ifneq ($(obj-m),) 57$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) 58$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) 59endif 60endif 61 62# =========================================================================== 63 64ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) 65lib-target := $(obj)/lib.a 66real-obj-y += $(obj)/lib-ksyms.o 67endif 68 69ifneq ($(strip $(real-obj-y) $(need-builtin)),) 70builtin-target := $(obj)/built-in.a 71endif 72 73ifeq ($(CONFIG_MODULES)$(need-modorder),y1) 74modorder-target := $(obj)/modules.order 75endif 76 77mod-targets := $(patsubst %.o, %.mod, $(obj-m)) 78 79__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ 80 $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \ 81 $(subdir-ym) $(always) 82 @: 83 84# Linus' kernel sanity checking tool 85ifeq ($(KBUILD_CHECKSRC),1) 86 quiet_cmd_checksrc = CHECK $< 87 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 88else ifeq ($(KBUILD_CHECKSRC),2) 89 quiet_cmd_force_checksrc = CHECK $< 90 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 91endif 92 93ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),) 94 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 95endif 96 97# Compile C sources (.c) 98# --------------------------------------------------------------------------- 99 100# Default is built-in, unless we know otherwise 101$(foreach x, i ll lst o s symtypes, $(patsubst %.o,%.$(x),$(real-obj-m))): \ 102 part-of-module := y 103 104modkern_cflags = \ 105 $(if $(part-of-module), \ 106 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \ 107 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL)) 108quiet_modtag = $(if $(part-of-module),[M], ) 109 110quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 111 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $< 112 113$(obj)/%.s: $(src)/%.c FORCE 114 $(call if_changed_dep,cc_s_c) 115 116quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 117cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 118 119$(obj)/%.i: $(src)/%.c FORCE 120 $(call if_changed_dep,cpp_i_c) 121 122# These mirror gensymtypes_S and co below, keep them in synch. 123cmd_gensymtypes_c = \ 124 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 125 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 126 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 127 $(if $(KBUILD_PRESERVE),-p) \ 128 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 129 130quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 131cmd_cc_symtypes_c = \ 132 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ 133 test -s $@ || rm -f $@ 134 135$(obj)/%.symtypes : $(src)/%.c FORCE 136 $(call cmd,cc_symtypes_c) 137 138# LLVM assembly 139# Generate .ll files from .c 140quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 141 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< 142 143$(obj)/%.ll: $(src)/%.c FORCE 144 $(call if_changed_dep,cc_ll_c) 145 146# C (.c) files 147# The C file is compiled and updated dependency information is generated. 148# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 149 150quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 151 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 152 153ifdef CONFIG_MODVERSIONS 154# When module versioning is enabled the following steps are executed: 155# o compile a <file>.o from <file>.c 156# o if <file>.o doesn't contain a __ksymtab version, i.e. does 157# not export symbols, it's done. 158# o otherwise, we calculate symbol versions using the good old 159# genksyms on the preprocessed source and postprocess them in a way 160# that they are usable as a linker script 161# o generate .tmp_<file>.o from <file>.o using the linker to 162# replace the unresolved symbols __crc_exported_symbol with 163# the actual value of the checksum generated by genksyms 164# o remove .tmp_<file>.o to <file>.o 165 166cmd_modversions_c = \ 167 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 168 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 169 > $(@D)/.tmp_$(@F:.o=.ver); \ 170 \ 171 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 172 -T $(@D)/.tmp_$(@F:.o=.ver); \ 173 mv -f $(@D)/.tmp_$(@F) $@; \ 174 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 175 fi 176endif 177 178ifdef CONFIG_FTRACE_MCOUNT_RECORD 179ifndef CC_USING_RECORD_MCOUNT 180# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 181ifdef BUILD_C_RECORDMCOUNT 182ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 183 RECORDMCOUNT_FLAGS = -w 184endif 185# Due to recursion, we must skip empty.o. 186# The empty.o file is created in the make process in order to determine 187# the target endianness and word size. It is made before all other C 188# files, including recordmcount. 189sub_cmd_record_mcount = \ 190 if [ $(@) != "scripts/mod/empty.o" ]; then \ 191 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 192 fi; 193recordmcount_source := $(srctree)/scripts/recordmcount.c \ 194 $(srctree)/scripts/recordmcount.h 195else 196sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 197 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 198 "$(if $(CONFIG_64BIT),64,32)" \ 199 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 200 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 201 "$(if $(part-of-module),1,0)" "$(@)"; 202recordmcount_source := $(srctree)/scripts/recordmcount.pl 203endif # BUILD_C_RECORDMCOUNT 204cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 205 $(sub_cmd_record_mcount)) 206endif # CC_USING_RECORD_MCOUNT 207endif # CONFIG_FTRACE_MCOUNT_RECORD 208 209ifdef CONFIG_STACK_VALIDATION 210ifneq ($(SKIP_STACK_VALIDATION),1) 211 212__objtool_obj := $(objtree)/tools/objtool/objtool 213 214objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check) 215 216objtool_args += $(if $(part-of-module), --module,) 217 218ifndef CONFIG_FRAME_POINTER 219objtool_args += --no-fp 220endif 221ifdef CONFIG_GCOV_KERNEL 222objtool_args += --no-unreachable 223endif 224ifdef CONFIG_RETPOLINE 225 objtool_args += --retpoline 226endif 227ifdef CONFIG_X86_SMAP 228 objtool_args += --uaccess 229endif 230 231# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 232# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 233# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 234cmd_objtool = $(if $(patsubst y%,, \ 235 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 236 $(__objtool_obj) $(objtool_args) $@) 237objtool_obj = $(if $(patsubst y%,, \ 238 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 239 $(__objtool_obj)) 240 241endif # SKIP_STACK_VALIDATION 242endif # CONFIG_STACK_VALIDATION 243 244# Rebuild all objects when objtool changes, or is enabled/disabled. 245objtool_dep = $(objtool_obj) \ 246 $(wildcard include/config/orc/unwinder.h \ 247 include/config/stack/validation.h) 248 249ifdef CONFIG_TRIM_UNUSED_KSYMS 250cmd_gen_ksymdeps = \ 251 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 252endif 253 254define rule_cc_o_c 255 $(call cmd,checksrc) 256 $(call cmd_and_fixdep,cc_o_c) 257 $(call cmd,gen_ksymdeps) 258 $(call cmd,checkdoc) 259 $(call cmd,objtool) 260 $(call cmd,modversions_c) 261 $(call cmd,record_mcount) 262endef 263 264define rule_as_o_S 265 $(call cmd_and_fixdep,as_o_S) 266 $(call cmd,gen_ksymdeps) 267 $(call cmd,objtool) 268 $(call cmd,modversions_S) 269endef 270 271# List module undefined symbols (or empty line if not enabled) 272ifdef CONFIG_TRIM_UNUSED_KSYMS 273cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo 274else 275cmd_undef_syms = echo 276endif 277 278# Built-in and composite module parts 279$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE 280 $(call cmd,force_checksrc) 281 $(call if_changed_rule,cc_o_c) 282 283cmd_mod = { \ 284 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ 285 $(cmd_undef_syms); \ 286 } > $@ 287 288$(obj)/%.mod: $(obj)/%.o FORCE 289 $(call if_changed,mod) 290 291targets += $(mod-targets) 292 293quiet_cmd_cc_lst_c = MKLST $@ 294 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 295 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 296 System.map $(OBJDUMP) > $@ 297 298$(obj)/%.lst: $(src)/%.c FORCE 299 $(call if_changed_dep,cc_lst_c) 300 301# header test (header-test-y, header-test-m target) 302# --------------------------------------------------------------------------- 303 304quiet_cmd_cc_s_h = CC $@ 305 cmd_cc_s_h = $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $< 306 307$(obj)/%.h.s: $(src)/%.h FORCE 308 $(call if_changed_dep,cc_s_h) 309 310# Compile assembler sources (.S) 311# --------------------------------------------------------------------------- 312 313modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) 314 315$(real-obj-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) 316$(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) 317 318# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 319# or a file that it includes, in order to get versioned symbols. We build a 320# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 321# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 322# 323# This is convoluted. The .S file must first be preprocessed to run guards and 324# expand names, then the resulting exports must be constructed into plain 325# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 326# to make the genksyms input. 327# 328# These mirror gensymtypes_c and co above, keep them in synch. 329cmd_gensymtypes_S = \ 330 { echo "\#include <linux/kernel.h>" ; \ 331 echo "\#include <asm/asm-prototypes.h>" ; \ 332 $(CPP) $(a_flags) $< | \ 333 grep "\<___EXPORT_SYMBOL\>" | \ 334 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 335 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 336 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 337 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 338 $(if $(KBUILD_PRESERVE),-p) \ 339 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 340 341quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 342cmd_cc_symtypes_S = \ 343 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 344 test -s $@ || rm -f $@ 345 346$(obj)/%.symtypes : $(src)/%.S FORCE 347 $(call cmd,cc_symtypes_S) 348 349 350quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 351cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 352 353$(obj)/%.s: $(src)/%.S FORCE 354 $(call if_changed_dep,cpp_s_S) 355 356quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 357 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 358 359ifdef CONFIG_MODVERSIONS 360 361ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h) 362 363ifneq ($(ASM_PROTOTYPES),) 364 365# versioning matches the C process described above, with difference that 366# we parse asm-prototypes.h C header to get function definitions. 367 368cmd_modversions_S = \ 369 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 370 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 371 > $(@D)/.tmp_$(@F:.o=.ver); \ 372 \ 373 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 374 -T $(@D)/.tmp_$(@F:.o=.ver); \ 375 mv -f $(@D)/.tmp_$(@F) $@; \ 376 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 377 fi 378endif 379endif 380 381$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE 382 $(call if_changed_rule,as_o_S) 383 384targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y) 385targets += $(extra-y) $(MAKECMDGOALS) $(always) 386 387# Linker scripts preprocessor (.lds.S -> .lds) 388# --------------------------------------------------------------------------- 389quiet_cmd_cpp_lds_S = LDS $@ 390 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 391 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 392 393$(obj)/%.lds: $(src)/%.lds.S FORCE 394 $(call if_changed_dep,cpp_lds_S) 395 396# ASN.1 grammar 397# --------------------------------------------------------------------------- 398quiet_cmd_asn1_compiler = ASN.1 $@ 399 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 400 $(subst .h,.c,$@) $(subst .c,.h,$@) 401 402$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 403 $(call cmd,asn1_compiler) 404 405# Build the compiled-in targets 406# --------------------------------------------------------------------------- 407 408# To build objects in subdirs, we need to descend into the directories 409$(sort $(subdir-obj-y)): $(subdir-ym) ; 410 411# 412# Rule to compile a set of .o files into one .a file (without symbol table) 413# 414ifdef builtin-target 415 416quiet_cmd_ar_builtin = AR $@ 417 cmd_ar_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs) 418 419$(builtin-target): $(real-obj-y) FORCE 420 $(call if_changed,ar_builtin) 421 422targets += $(builtin-target) 423endif # builtin-target 424 425# 426# Rule to create modules.order file 427# 428# Create commands to either record .ko file or cat modules.order from 429# a subdirectory 430$(modorder-target): $(subdir-ym) FORCE 431 $(Q){ $(foreach m, $(modorder), \ 432 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \ 433 | $(AWK) '!x[$$0]++' - > $@ 434 435# 436# Rule to compile a set of .o files into one .a file (with symbol table) 437# 438ifdef lib-target 439 440$(lib-target): $(lib-y) FORCE 441 $(call if_changed,ar) 442 443targets += $(lib-target) 444 445dummy-object = $(obj)/.lib_exports.o 446ksyms-lds = $(dot-target).lds 447 448quiet_cmd_export_list = EXPORTS $@ 449cmd_export_list = $(OBJDUMP) -h $< | \ 450 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\ 451 rm -f $(dummy-object);\ 452 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\ 453 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\ 454 rm $(dummy-object) $(ksyms-lds) 455 456$(obj)/lib-ksyms.o: $(lib-target) FORCE 457 $(call if_changed,export_list) 458 459targets += $(obj)/lib-ksyms.o 460 461endif 462 463# NOTE: 464# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object 465# module is turned into a multi object module, $^ will contain header file 466# dependencies recorded in the .*.cmd file. 467quiet_cmd_link_multi-m = LD [M] $@ 468 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) 469 470$(multi-used-m): FORCE 471 $(call if_changed,link_multi-m) 472$(call multi_depend, $(multi-used-m), .o, -objs -y -m) 473 474targets += $(multi-used-m) 475targets := $(filter-out $(PHONY), $(targets)) 476 477# Add intermediate targets: 478# When building objects with specific suffix patterns, add intermediate 479# targets that the final targets are derived from. 480intermediate_targets = $(foreach sfx, $(2), \ 481 $(patsubst %$(strip $(1)),%$(sfx), \ 482 $(filter %$(strip $(1)), $(targets)))) 483# %.asn1.o <- %.asn1.[ch] <- %.asn1 484# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 485# %.lex.o <- %.lex.c <- %.l 486# %.tab.o <- %.tab.[ch] <- %.y 487targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 488 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 489 $(call intermediate_targets, .lex.o, .lex.c) \ 490 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 491 492# Descending 493# --------------------------------------------------------------------------- 494 495PHONY += $(subdir-ym) 496$(subdir-ym): 497 $(Q)$(MAKE) $(build)=$@ \ 498 need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \ 499 need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1)) 500 501# Add FORCE to the prequisites of a target to force it to be always rebuilt. 502# --------------------------------------------------------------------------- 503 504PHONY += FORCE 505 506FORCE: 507 508# Read all saved command lines and dependencies for the $(targets) we 509# may be building above, using $(if_changed{,_dep}). As an 510# optimization, we don't need to read them if the target does not 511# exist, we will rebuild anyway in that case. 512 513existing-targets := $(wildcard $(sort $(targets))) 514 515-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 516 517ifdef building_out_of_srctree 518# Create directories for object files if they do not exist 519obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets)))) 520# If targets exist, their directories apparently exist. Skip mkdir. 521existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 522obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 523ifneq ($(obj-dirs),) 524$(shell mkdir -p $(obj-dirs)) 525endif 526endif 527 528.PHONY: $(PHONY) 529