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