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 ($(need-modorder),) 56ifneq ($(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, $(obj-m)) 78 79# Linus' kernel sanity checking tool 80ifeq ($(KBUILD_CHECKSRC),1) 81 quiet_cmd_checksrc = CHECK $< 82 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 83else ifeq ($(KBUILD_CHECKSRC),2) 84 quiet_cmd_force_checksrc = CHECK $< 85 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< 86endif 87 88ifneq ($(KBUILD_EXTRA_WARN),) 89 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $< 90endif 91 92# Compile C sources (.c) 93# --------------------------------------------------------------------------- 94 95quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 96 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $< 97 98$(obj)/%.s: $(src)/%.c FORCE 99 $(call if_changed_dep,cc_s_c) 100 101quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ 102cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 103 104$(obj)/%.i: $(src)/%.c FORCE 105 $(call if_changed_dep,cpp_i_c) 106 107# These mirror gensymtypes_S and co below, keep them in synch. 108cmd_gensymtypes_c = \ 109 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 110 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 111 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 112 $(if $(KBUILD_PRESERVE),-p) \ 113 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 114 115quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 116cmd_cc_symtypes_c = \ 117 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ 118 test -s $@ || rm -f $@ 119 120$(obj)/%.symtypes : $(src)/%.c FORCE 121 $(call cmd,cc_symtypes_c) 122 123# LLVM assembly 124# Generate .ll files from .c 125quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ 126 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< 127 128$(obj)/%.ll: $(src)/%.c FORCE 129 $(call if_changed_dep,cc_ll_c) 130 131# C (.c) files 132# The C file is compiled and updated dependency information is generated. 133# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 134 135quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 136 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 137 138ifdef CONFIG_MODVERSIONS 139# When module versioning is enabled the following steps are executed: 140# o compile a <file>.o from <file>.c 141# o if <file>.o doesn't contain a __ksymtab version, i.e. does 142# not export symbols, it's done. 143# o otherwise, we calculate symbol versions using the good old 144# genksyms on the preprocessed source and postprocess them in a way 145# that they are usable as a linker script 146# o generate .tmp_<file>.o from <file>.o using the linker to 147# replace the unresolved symbols __crc_exported_symbol with 148# the actual value of the checksum generated by genksyms 149# o remove .tmp_<file>.o to <file>.o 150 151cmd_modversions_c = \ 152 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 153 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 154 > $(@D)/.tmp_$(@F:.o=.ver); \ 155 \ 156 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 157 -T $(@D)/.tmp_$(@F:.o=.ver); \ 158 mv -f $(@D)/.tmp_$(@F) $@; \ 159 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 160 fi 161endif 162 163ifdef CONFIG_FTRACE_MCOUNT_RECORD 164ifndef CC_USING_RECORD_MCOUNT 165# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl 166ifdef BUILD_C_RECORDMCOUNT 167ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 168 RECORDMCOUNT_FLAGS = -w 169endif 170# Due to recursion, we must skip empty.o. 171# The empty.o file is created in the make process in order to determine 172# the target endianness and word size. It is made before all other C 173# files, including recordmcount. 174sub_cmd_record_mcount = \ 175 if [ $(@) != "scripts/mod/empty.o" ]; then \ 176 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 177 fi; 178recordmcount_source := $(srctree)/scripts/recordmcount.c \ 179 $(srctree)/scripts/recordmcount.h 180else 181sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 182 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 183 "$(if $(CONFIG_64BIT),64,32)" \ 184 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ 185 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ 186 "$(if $(part-of-module),1,0)" "$(@)"; 187recordmcount_source := $(srctree)/scripts/recordmcount.pl 188endif # BUILD_C_RECORDMCOUNT 189cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \ 190 $(sub_cmd_record_mcount)) 191endif # CC_USING_RECORD_MCOUNT 192endif # CONFIG_FTRACE_MCOUNT_RECORD 193 194ifdef CONFIG_STACK_VALIDATION 195ifneq ($(SKIP_STACK_VALIDATION),1) 196 197__objtool_obj := $(objtree)/tools/objtool/objtool 198 199objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check) 200 201objtool_args += $(if $(part-of-module), --module,) 202 203ifndef CONFIG_FRAME_POINTER 204objtool_args += --no-fp 205endif 206ifdef CONFIG_GCOV_KERNEL 207objtool_args += --no-unreachable 208endif 209ifdef CONFIG_RETPOLINE 210 objtool_args += --retpoline 211endif 212ifdef CONFIG_X86_SMAP 213 objtool_args += --uaccess 214endif 215 216# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory 217# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file 218# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file 219cmd_objtool = $(if $(patsubst y%,, \ 220 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 221 $(__objtool_obj) $(objtool_args) $@) 222objtool_obj = $(if $(patsubst y%,, \ 223 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ 224 $(__objtool_obj)) 225 226endif # SKIP_STACK_VALIDATION 227endif # CONFIG_STACK_VALIDATION 228 229# Rebuild all objects when objtool changes, or is enabled/disabled. 230objtool_dep = $(objtool_obj) \ 231 $(wildcard include/config/orc/unwinder.h \ 232 include/config/stack/validation.h) 233 234ifdef CONFIG_TRIM_UNUSED_KSYMS 235cmd_gen_ksymdeps = \ 236 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd 237endif 238 239define rule_cc_o_c 240 $(call cmd,checksrc) 241 $(call cmd_and_fixdep,cc_o_c) 242 $(call cmd,gen_ksymdeps) 243 $(call cmd,checkdoc) 244 $(call cmd,objtool) 245 $(call cmd,modversions_c) 246 $(call cmd,record_mcount) 247endef 248 249define rule_as_o_S 250 $(call cmd_and_fixdep,as_o_S) 251 $(call cmd,gen_ksymdeps) 252 $(call cmd,objtool) 253 $(call cmd,modversions_S) 254endef 255 256# List module undefined symbols (or empty line if not enabled) 257ifdef CONFIG_TRIM_UNUSED_KSYMS 258cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo 259else 260cmd_undef_syms = echo 261endif 262 263# Built-in and composite module parts 264$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE 265 $(call cmd,force_checksrc) 266 $(call if_changed_rule,cc_o_c) 267 268cmd_mod = { \ 269 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ 270 $(cmd_undef_syms); \ 271 } > $@ 272 273$(obj)/%.mod: $(obj)/%.o FORCE 274 $(call if_changed,mod) 275 276targets += $(mod-targets) 277 278quiet_cmd_cc_lst_c = MKLST $@ 279 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 280 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 281 System.map $(OBJDUMP) > $@ 282 283$(obj)/%.lst: $(src)/%.c FORCE 284 $(call if_changed_dep,cc_lst_c) 285 286# header test (header-test-y, header-test-m target) 287# --------------------------------------------------------------------------- 288 289quiet_cmd_cc_s_h = CC $@ 290 cmd_cc_s_h = $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $< 291 292$(obj)/%.h.s: $(src)/%.h FORCE 293 $(call if_changed_dep,cc_s_h) 294 295# Compile assembler sources (.S) 296# --------------------------------------------------------------------------- 297 298# .S file exports must have their C prototypes defined in asm/asm-prototypes.h 299# or a file that it includes, in order to get versioned symbols. We build a 300# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from 301# the .S file (with trailing ';'), and run genksyms on that, to extract vers. 302# 303# This is convoluted. The .S file must first be preprocessed to run guards and 304# expand names, then the resulting exports must be constructed into plain 305# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed 306# to make the genksyms input. 307# 308# These mirror gensymtypes_c and co above, keep them in synch. 309cmd_gensymtypes_S = \ 310 { echo "\#include <linux/kernel.h>" ; \ 311 echo "\#include <asm/asm-prototypes.h>" ; \ 312 $(CPP) $(a_flags) $< | \ 313 grep "\<___EXPORT_SYMBOL\>" | \ 314 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ 315 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ 316 scripts/genksyms/genksyms $(if $(1), -T $(2)) \ 317 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \ 318 $(if $(KBUILD_PRESERVE),-p) \ 319 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 320 321quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ 322cmd_cc_symtypes_S = \ 323 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ 324 test -s $@ || rm -f $@ 325 326$(obj)/%.symtypes : $(src)/%.S FORCE 327 $(call cmd,cc_symtypes_S) 328 329 330quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ 331cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< 332 333$(obj)/%.s: $(src)/%.S FORCE 334 $(call if_changed_dep,cpp_s_S) 335 336quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 337 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 338 339ifdef CONFIG_ASM_MODVERSIONS 340 341# versioning matches the C process described above, with difference that 342# we parse asm-prototypes.h C header to get function definitions. 343 344cmd_modversions_S = \ 345 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ 346 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 347 > $(@D)/.tmp_$(@F:.o=.ver); \ 348 \ 349 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ 350 -T $(@D)/.tmp_$(@F:.o=.ver); \ 351 mv -f $(@D)/.tmp_$(@F) $@; \ 352 rm -f $(@D)/.tmp_$(@F:.o=.ver); \ 353 fi 354endif 355 356$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE 357 $(call if_changed_rule,as_o_S) 358 359targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y) 360targets += $(extra-y) $(MAKECMDGOALS) $(always) 361 362# Linker scripts preprocessor (.lds.S -> .lds) 363# --------------------------------------------------------------------------- 364quiet_cmd_cpp_lds_S = LDS $@ 365 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \ 366 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 367 368$(obj)/%.lds: $(src)/%.lds.S FORCE 369 $(call if_changed_dep,cpp_lds_S) 370 371# ASN.1 grammar 372# --------------------------------------------------------------------------- 373quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch] 374 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 375 $(basename $@).c $(basename $@).h 376 377$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 378 $(call cmd,asn1_compiler) 379 380# Build the compiled-in targets 381# --------------------------------------------------------------------------- 382 383# To build objects in subdirs, we need to descend into the directories 384$(sort $(subdir-obj-y)): $(subdir-ym) ; 385 386# 387# Rule to compile a set of .o files into one .a file (without symbol table) 388# 389ifdef builtin-target 390 391quiet_cmd_ar_builtin = AR $@ 392 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) 393 394$(builtin-target): $(real-obj-y) FORCE 395 $(call if_changed,ar_builtin) 396 397targets += $(builtin-target) 398endif # builtin-target 399 400# 401# Rule to create modules.order file 402# 403# Create commands to either record .ko file or cat modules.order from 404# a subdirectory 405$(modorder-target): $(subdir-ym) FORCE 406 $(Q){ $(foreach m, $(modorder), \ 407 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \ 408 | $(AWK) '!x[$$0]++' - > $@ 409 410# 411# Rule to compile a set of .o files into one .a file (with symbol table) 412# 413ifdef lib-target 414 415$(lib-target): $(lib-y) FORCE 416 $(call if_changed,ar) 417 418targets += $(lib-target) 419 420dummy-object = $(obj)/.lib_exports.o 421ksyms-lds = $(dot-target).lds 422 423quiet_cmd_export_list = EXPORTS $@ 424cmd_export_list = $(OBJDUMP) -h $< | \ 425 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\ 426 rm -f $(dummy-object);\ 427 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\ 428 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\ 429 rm $(dummy-object) $(ksyms-lds) 430 431$(obj)/lib-ksyms.o: $(lib-target) FORCE 432 $(call if_changed,export_list) 433 434targets += $(obj)/lib-ksyms.o 435 436endif 437 438# NOTE: 439# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object 440# module is turned into a multi object module, $^ will contain header file 441# dependencies recorded in the .*.cmd file. 442quiet_cmd_link_multi-m = LD [M] $@ 443 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) 444 445$(multi-used-m): FORCE 446 $(call if_changed,link_multi-m) 447$(call multi_depend, $(multi-used-m), .o, -objs -y -m) 448 449targets += $(multi-used-m) 450targets := $(filter-out $(PHONY), $(targets)) 451 452# Add intermediate targets: 453# When building objects with specific suffix patterns, add intermediate 454# targets that the final targets are derived from. 455intermediate_targets = $(foreach sfx, $(2), \ 456 $(patsubst %$(strip $(1)),%$(sfx), \ 457 $(filter %$(strip $(1)), $(targets)))) 458# %.asn1.o <- %.asn1.[ch] <- %.asn1 459# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts 460# %.lex.o <- %.lex.c <- %.l 461# %.tab.o <- %.tab.[ch] <- %.y 462targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ 463 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \ 464 $(call intermediate_targets, .lex.o, .lex.c) \ 465 $(call intermediate_targets, .tab.o, .tab.c .tab.h) 466 467# Build 468# --------------------------------------------------------------------------- 469 470ifdef single-build 471 472curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \ 473 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x)))) 474 475# Handle single targets without any rule: show "Nothing to be done for ..." or 476# "No rule to make target ..." depending on whether the target exists. 477unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \ 478 $(filter $(obj)/%, \ 479 $(filter-out $(curdir-single), \ 480 $(KBUILD_SINGLE_TARGETS)))) 481 482__build: $(curdir-single) $(subdir-ym) 483ifneq ($(unknown-single),) 484 $(Q)$(MAKE) -f /dev/null $(unknown-single) 485endif 486 @: 487 488ifeq ($(curdir-single),) 489# Nothing to do in this directory. Do not include any .*.cmd file for speed-up 490targets := 491else 492targets += $(curdir-single) 493endif 494 495else 496 497__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ 498 $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \ 499 $(subdir-ym) $(always) 500 @: 501 502endif 503 504# Descending 505# --------------------------------------------------------------------------- 506 507PHONY += $(subdir-ym) 508$(subdir-ym): 509 $(Q)$(MAKE) $(build)=$@ \ 510 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \ 511 need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \ 512 need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1)) 513 514# Add FORCE to the prequisites of a target to force it to be always rebuilt. 515# --------------------------------------------------------------------------- 516 517PHONY += FORCE 518 519FORCE: 520 521# Read all saved command lines and dependencies for the $(targets) we 522# may be building above, using $(if_changed{,_dep}). As an 523# optimization, we don't need to read them if the target does not 524# exist, we will rebuild anyway in that case. 525 526existing-targets := $(wildcard $(sort $(targets))) 527 528-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) 529 530ifdef building_out_of_srctree 531# Create directories for object files if they do not exist 532obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets)))) 533# If targets exist, their directories apparently exist. Skip mkdir. 534existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets)))) 535obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs))) 536ifneq ($(obj-dirs),) 537$(shell mkdir -p $(obj-dirs)) 538endif 539endif 540 541.PHONY: $(PHONY) 542