1# ========================================================================== 2# Building 3# ========================================================================== 4 5src := $(obj) 6 7PHONY := __build 8__build: 9 10# Init all relevant variables used in kbuild files so 11# 1) they have correct type 12# 2) they do not inherit any value from the environment 13obj-y := 14obj-m := 15lib-y := 16lib-m := 17always := 18targets := 19subdir-y := 20subdir-m := 21EXTRA_AFLAGS := 22EXTRA_CFLAGS := 23EXTRA_CPPFLAGS := 24EXTRA_LDFLAGS := 25asflags-y := 26ccflags-y := 27cppflags-y := 28ldflags-y := 29 30subdir-asflags-y := 31subdir-ccflags-y := 32 33# Read auto.conf if it exists, otherwise ignore 34-include include/config/auto.conf 35 36include scripts/Kbuild.include 37 38# For backward compatibility check that these variables do not change 39save-cflags := $(CFLAGS) 40 41# The filename Kbuild has precedence over Makefile 42kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 43kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) 44include $(kbuild-file) 45 46# If the save-* variables changed error out 47ifeq ($(KBUILD_NOPEDANTIC),) 48 ifneq ("$(save-cflags)","$(CFLAGS)") 49 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y) 50 endif 51endif 52 53# 54# make W=... settings 55# 56# W=1 - warnings that may be relevant and does not occur too often 57# W=2 - warnings that occur quite often but may still be relevant 58# W=3 - the more obscure warnings, can most likely be ignored 59# 60# $(call cc-option, -W...) handles gcc -W.. options which 61# are not supported by all versions of the compiler 62ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS 63warning- := $(empty) 64 65warning-1 := -Wextra -Wunused -Wno-unused-parameter 66warning-1 += -Wmissing-declarations 67warning-1 += -Wmissing-format-attribute 68warning-1 += -Wmissing-prototypes 69warning-1 += -Wold-style-definition 70warning-1 += $(call cc-option, -Wmissing-include-dirs) 71warning-1 += $(call cc-option, -Wunused-but-set-variable) 72warning-1 += $(call cc-disable-warning, missing-field-initializers) 73 74warning-2 := -Waggregate-return 75warning-2 += -Wcast-align 76warning-2 += -Wdisabled-optimization 77warning-2 += -Wnested-externs 78warning-2 += -Wshadow 79warning-2 += $(call cc-option, -Wlogical-op) 80warning-2 += $(call cc-option, -Wmissing-field-initializers) 81 82warning-3 := -Wbad-function-cast 83warning-3 += -Wcast-qual 84warning-3 += -Wconversion 85warning-3 += -Wpacked 86warning-3 += -Wpadded 87warning-3 += -Wpointer-arith 88warning-3 += -Wredundant-decls 89warning-3 += -Wswitch-default 90warning-3 += $(call cc-option, -Wpacked-bitfield-compat) 91warning-3 += $(call cc-option, -Wvla) 92 93warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) 94warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) 95warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) 96 97ifeq ("$(strip $(warning))","") 98 $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown) 99endif 100 101KBUILD_CFLAGS += $(warning) 102endif 103 104include scripts/Makefile.lib 105 106ifdef host-progs 107ifneq ($(hostprogs-y),$(host-progs)) 108$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!) 109hostprogs-y += $(host-progs) 110endif 111endif 112 113# Do not include host rules unless needed 114ifneq ($(hostprogs-y)$(hostprogs-m),) 115include scripts/Makefile.host 116endif 117 118ifneq ($(KBUILD_SRC),) 119# Create output directory if not already present 120_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj)) 121 122# Create directories for object files if directory does not exist 123# Needed when obj-y := dir/file.o syntax is used 124_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d))) 125endif 126 127ifndef obj 128$(warning kbuild: Makefile.build is included improperly) 129endif 130 131# =========================================================================== 132 133ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),) 134lib-target := $(obj)/lib.a 135endif 136 137ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(subdir-m) $(lib-target)),) 138builtin-target := $(obj)/built-in.o 139endif 140 141modorder-target := $(obj)/modules.order 142 143# We keep a list of all modules in $(MODVERDIR) 144 145__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ 146 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \ 147 $(subdir-ym) $(always) 148 @: 149 150# Linus' kernel sanity checking tool 151ifneq ($(KBUILD_CHECKSRC),0) 152 ifeq ($(KBUILD_CHECKSRC),2) 153 quiet_cmd_force_checksrc = CHECK $< 154 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; 155 else 156 quiet_cmd_checksrc = CHECK $< 157 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; 158 endif 159endif 160 161# Do section mismatch analysis for each module/built-in.o 162ifdef CONFIG_DEBUG_SECTION_MISMATCH 163 cmd_secanalysis = ; scripts/mod/modpost $@ 164endif 165 166# Compile C sources (.c) 167# --------------------------------------------------------------------------- 168 169# Default is built-in, unless we know otherwise 170modkern_cflags = \ 171 $(if $(part-of-module), \ 172 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \ 173 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL)) 174quiet_modtag := $(empty) $(empty) 175 176$(real-objs-m) : part-of-module := y 177$(real-objs-m:.o=.i) : part-of-module := y 178$(real-objs-m:.o=.s) : part-of-module := y 179$(real-objs-m:.o=.lst): part-of-module := y 180 181$(real-objs-m) : quiet_modtag := [M] 182$(real-objs-m:.o=.i) : quiet_modtag := [M] 183$(real-objs-m:.o=.s) : quiet_modtag := [M] 184$(real-objs-m:.o=.lst): quiet_modtag := [M] 185 186$(obj-m) : quiet_modtag := [M] 187 188# Default for not multi-part modules 189modname = $(basetarget) 190 191$(multi-objs-m) : modname = $(modname-multi) 192$(multi-objs-m:.o=.i) : modname = $(modname-multi) 193$(multi-objs-m:.o=.s) : modname = $(modname-multi) 194$(multi-objs-m:.o=.lst) : modname = $(modname-multi) 195$(multi-objs-y) : modname = $(modname-multi) 196$(multi-objs-y:.o=.i) : modname = $(modname-multi) 197$(multi-objs-y:.o=.s) : modname = $(modname-multi) 198$(multi-objs-y:.o=.lst) : modname = $(modname-multi) 199 200quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 201cmd_cc_s_c = $(CC) $(c_flags) -fverbose-asm -S -o $@ $< 202 203$(obj)/%.s: $(src)/%.c FORCE 204 $(call if_changed_dep,cc_s_c) 205 206quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@ 207cmd_cc_i_c = $(CPP) $(c_flags) -o $@ $< 208 209$(obj)/%.i: $(src)/%.c FORCE 210 $(call if_changed_dep,cc_i_c) 211 212cmd_gensymtypes = \ 213 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 214 $(GENKSYMS) $(if $(1), -T $(2)) \ 215 $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \ 216 $(if $(KBUILD_PRESERVE),-p) \ 217 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) 218 219quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 220cmd_cc_symtypes_c = \ 221 set -e; \ 222 $(call cmd_gensymtypes,true,$@) >/dev/null; \ 223 test -s $@ || rm -f $@ 224 225$(obj)/%.symtypes : $(src)/%.c FORCE 226 $(call cmd,cc_symtypes_c) 227 228# C (.c) files 229# The C file is compiled and updated dependency information is generated. 230# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 231 232quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 233 234ifndef CONFIG_MODVERSIONS 235cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 236 237else 238# When module versioning is enabled the following steps are executed: 239# o compile a .tmp_<file>.o from <file>.c 240# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does 241# not export symbols, we just rename .tmp_<file>.o to <file>.o and 242# are done. 243# o otherwise, we calculate symbol versions using the good old 244# genksyms on the preprocessed source and postprocess them in a way 245# that they are usable as a linker script 246# o generate <file>.o from .tmp_<file>.o using the linker to 247# replace the unresolved symbols __crc_exported_symbol with 248# the actual value of the checksum generated by genksyms 249 250cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $< 251cmd_modversions = \ 252 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \ 253 $(call cmd_gensymtypes,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ 254 > $(@D)/.tmp_$(@F:.o=.ver); \ 255 \ 256 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \ 257 -T $(@D)/.tmp_$(@F:.o=.ver); \ 258 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \ 259 else \ 260 mv -f $(@D)/.tmp_$(@F) $@; \ 261 fi; 262endif 263 264ifdef CONFIG_FTRACE_MCOUNT_RECORD 265ifdef BUILD_C_RECORDMCOUNT 266ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") 267 RECORDMCOUNT_FLAGS = -w 268endif 269# Due to recursion, we must skip empty.o. 270# The empty.o file is created in the make process in order to determine 271# the target endianness and word size. It is made before all other C 272# files, including recordmcount. 273sub_cmd_record_mcount = \ 274 if [ $(@) != "scripts/mod/empty.o" ]; then \ 275 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \ 276 fi; 277recordmcount_source := $(srctree)/scripts/recordmcount.c \ 278 $(srctree)/scripts/recordmcount.h 279else 280sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 281 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ 282 "$(if $(CONFIG_64BIT),64,32)" \ 283 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \ 284 "$(LD)" "$(NM)" "$(RM)" "$(MV)" \ 285 "$(if $(part-of-module),1,0)" "$(@)"; 286recordmcount_source := $(srctree)/scripts/recordmcount.pl 287endif 288cmd_record_mcount = \ 289 if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then \ 290 $(sub_cmd_record_mcount) \ 291 fi; 292endif 293 294define rule_cc_o_c 295 $(call echo-cmd,checksrc) $(cmd_checksrc) \ 296 $(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \ 297 $(cmd_modversions) \ 298 $(call echo-cmd,record_mcount) \ 299 $(cmd_record_mcount) \ 300 scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \ 301 $(dot-target).tmp; \ 302 rm -f $(depfile); \ 303 mv -f $(dot-target).tmp $(dot-target).cmd 304endef 305 306# Built-in and composite module parts 307$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE 308 $(call cmd,force_checksrc) 309 $(call if_changed_rule,cc_o_c) 310 311# Single-part modules are special since we need to mark them in $(MODVERDIR) 312 313$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE 314 $(call cmd,force_checksrc) 315 $(call if_changed_rule,cc_o_c) 316 @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod) 317 318quiet_cmd_cc_lst_c = MKLST $@ 319 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 320 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 321 System.map $(OBJDUMP) > $@ 322 323$(obj)/%.lst: $(src)/%.c FORCE 324 $(call if_changed_dep,cc_lst_c) 325 326# Compile assembler sources (.S) 327# --------------------------------------------------------------------------- 328 329modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) 330 331$(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) 332$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) 333 334quiet_cmd_as_s_S = CPP $(quiet_modtag) $@ 335cmd_as_s_S = $(CPP) $(a_flags) -o $@ $< 336 337$(obj)/%.s: $(src)/%.S FORCE 338 $(call if_changed_dep,as_s_S) 339 340quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 341cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 342 343$(obj)/%.o: $(src)/%.S FORCE 344 $(call if_changed_dep,as_o_S) 345 346targets += $(real-objs-y) $(real-objs-m) $(lib-y) 347targets += $(extra-y) $(MAKECMDGOALS) $(always) 348 349# Linker scripts preprocessor (.lds.S -> .lds) 350# --------------------------------------------------------------------------- 351quiet_cmd_cpp_lds_S = LDS $@ 352 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \ 353 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< 354 355$(obj)/%.lds: $(src)/%.lds.S FORCE 356 $(call if_changed_dep,cpp_lds_S) 357 358# ASN.1 grammar 359# --------------------------------------------------------------------------- 360quiet_cmd_asn1_compiler = ASN.1 $@ 361 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \ 362 $(subst .h,.c,$@) $(subst .c,.h,$@) 363 364.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h 365 366$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler 367 $(call cmd,asn1_compiler) 368 369# Build the compiled-in targets 370# --------------------------------------------------------------------------- 371 372# To build objects in subdirs, we need to descend into the directories 373$(sort $(subdir-obj-y)): $(subdir-ym) ; 374 375# 376# Rule to compile a set of .o files into one .o file 377# 378ifdef builtin-target 379quiet_cmd_link_o_target = LD $@ 380# If the list of objects to link is empty, just create an empty built-in.o 381cmd_link_o_target = $(if $(strip $(obj-y)),\ 382 $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \ 383 $(cmd_secanalysis),\ 384 rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@) 385 386$(builtin-target): $(obj-y) FORCE 387 $(call if_changed,link_o_target) 388 389targets += $(builtin-target) 390endif # builtin-target 391 392# 393# Rule to create modules.order file 394# 395# Create commands to either record .ko file or cat modules.order from 396# a subdirectory 397modorder-cmds = \ 398 $(foreach m, $(modorder), \ 399 $(if $(filter %/modules.order, $m), \ 400 cat $m;, echo kernel/$m;)) 401 402$(modorder-target): $(subdir-ym) FORCE 403 $(Q)(cat /dev/null; $(modorder-cmds)) > $@ 404 405# 406# Rule to compile a set of .o files into one .a file 407# 408ifdef lib-target 409quiet_cmd_link_l_target = AR $@ 410cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y) 411 412$(lib-target): $(lib-y) FORCE 413 $(call if_changed,link_l_target) 414 415targets += $(lib-target) 416endif 417 418# 419# Rule to link composite objects 420# 421# Composite objects are specified in kbuild makefile as follows: 422# <composite-object>-objs := <list of .o files> 423# or 424# <composite-object>-y := <list of .o files> 425link_multi_deps = \ 426$(filter $(addprefix $(obj)/, \ 427$($(subst $(obj)/,,$(@:.o=-objs))) \ 428$($(subst $(obj)/,,$(@:.o=-y)))), $^) 429 430quiet_cmd_link_multi-y = LD $@ 431cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) 432 433quiet_cmd_link_multi-m = LD [M] $@ 434cmd_link_multi-m = $(cmd_link_multi-y) 435 436# We would rather have a list of rules like 437# foo.o: $(foo-objs) 438# but that's not so easy, so we rather make all composite objects depend 439# on the set of all their parts 440$(multi-used-y) : %.o: $(multi-objs-y) FORCE 441 $(call if_changed,link_multi-y) 442 443$(multi-used-m) : %.o: $(multi-objs-m) FORCE 444 $(call if_changed,link_multi-m) 445 @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod) 446 447targets += $(multi-used-y) $(multi-used-m) 448 449 450# Descending 451# --------------------------------------------------------------------------- 452 453PHONY += $(subdir-ym) 454$(subdir-ym): 455 $(Q)$(MAKE) $(build)=$@ 456 457# Add FORCE to the prequisites of a target to force it to be always rebuilt. 458# --------------------------------------------------------------------------- 459 460PHONY += FORCE 461 462FORCE: 463 464# Read all saved command lines and dependencies for the $(targets) we 465# may be building above, using $(if_changed{,_dep}). As an 466# optimization, we don't need to read them if the target does not 467# exist, we will rebuild anyway in that case. 468 469targets := $(wildcard $(sort $(targets))) 470cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd)) 471 472ifneq ($(cmd_files),) 473 include $(cmd_files) 474endif 475 476# Declare the contents of the .PHONY variable as phony. We keep that 477# information in a variable se we can use it in if_changed and friends. 478 479.PHONY: $(PHONY) 480