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