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