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 30# Read auto.conf if it exists, otherwise ignore 31-include include/config/auto.conf 32 33include scripts/Kbuild.include 34 35# For backward compatibility check that these variables do not change 36save-cflags := $(CFLAGS) 37 38# The filename Kbuild has precedence over Makefile 39kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 40kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) 41include $(kbuild-file) 42 43# If the save-* variables changed error out 44ifeq ($(KBUILD_NOPEDANTIC),) 45 ifneq ("$(save-cflags)","$(CFLAGS)") 46 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use EXTRA_CFLAGS) 47 endif 48endif 49include scripts/Makefile.lib 50 51ifdef host-progs 52ifneq ($(hostprogs-y),$(host-progs)) 53$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!) 54hostprogs-y += $(host-progs) 55endif 56endif 57 58# Do not include host rules unless needed 59ifneq ($(hostprogs-y)$(hostprogs-m),) 60include scripts/Makefile.host 61endif 62 63ifneq ($(KBUILD_SRC),) 64# Create output directory if not already present 65_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj)) 66 67# Create directories for object files if directory does not exist 68# Needed when obj-y := dir/file.o syntax is used 69_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d))) 70endif 71 72ifndef obj 73$(warning kbuild: Makefile.build is included improperly) 74endif 75 76# =========================================================================== 77 78ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),) 79lib-target := $(obj)/lib.a 80endif 81 82ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(lib-target)),) 83builtin-target := $(obj)/built-in.o 84endif 85 86modorder-target := $(obj)/modules.order 87 88# We keep a list of all modules in $(MODVERDIR) 89 90__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ 91 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \ 92 $(subdir-ym) $(always) 93 @: 94 95# Linus' kernel sanity checking tool 96ifneq ($(KBUILD_CHECKSRC),0) 97 ifeq ($(KBUILD_CHECKSRC),2) 98 quiet_cmd_force_checksrc = CHECK $< 99 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; 100 else 101 quiet_cmd_checksrc = CHECK $< 102 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; 103 endif 104endif 105 106# Do section mismatch analysis for each module/built-in.o 107ifdef CONFIG_DEBUG_SECTION_MISMATCH 108 cmd_secanalysis = ; scripts/mod/modpost $@ 109endif 110 111# Compile C sources (.c) 112# --------------------------------------------------------------------------- 113 114# Default is built-in, unless we know otherwise 115modkern_cflags := $(CFLAGS_KERNEL) 116quiet_modtag := $(empty) $(empty) 117 118$(real-objs-m) : modkern_cflags := $(CFLAGS_MODULE) 119$(real-objs-m:.o=.i) : modkern_cflags := $(CFLAGS_MODULE) 120$(real-objs-m:.o=.s) : modkern_cflags := $(CFLAGS_MODULE) 121$(real-objs-m:.o=.lst): modkern_cflags := $(CFLAGS_MODULE) 122 123$(real-objs-m) : quiet_modtag := [M] 124$(real-objs-m:.o=.i) : quiet_modtag := [M] 125$(real-objs-m:.o=.s) : quiet_modtag := [M] 126$(real-objs-m:.o=.lst): quiet_modtag := [M] 127 128$(obj-m) : quiet_modtag := [M] 129 130# Default for not multi-part modules 131modname = $(basetarget) 132 133$(multi-objs-m) : modname = $(modname-multi) 134$(multi-objs-m:.o=.i) : modname = $(modname-multi) 135$(multi-objs-m:.o=.s) : modname = $(modname-multi) 136$(multi-objs-m:.o=.lst) : modname = $(modname-multi) 137$(multi-objs-y) : modname = $(modname-multi) 138$(multi-objs-y:.o=.i) : modname = $(modname-multi) 139$(multi-objs-y:.o=.s) : modname = $(modname-multi) 140$(multi-objs-y:.o=.lst) : modname = $(modname-multi) 141 142quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 143cmd_cc_s_c = $(CC) $(c_flags) -fverbose-asm -S -o $@ $< 144 145$(obj)/%.s: $(src)/%.c FORCE 146 $(call if_changed_dep,cc_s_c) 147 148quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@ 149cmd_cc_i_c = $(CPP) $(c_flags) -o $@ $< 150 151$(obj)/%.i: $(src)/%.c FORCE 152 $(call if_changed_dep,cc_i_c) 153 154cmd_genksyms = \ 155 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ 156 $(GENKSYMS) -T $@ -A -a $(ARCH) \ 157 $(if $(KBUILD_PRESERVE),-p) \ 158 $(if $(1),-r $(firstword $(wildcard $(@:.symtypes=.symref) /dev/null))) 159 160quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 161cmd_cc_symtypes_c = \ 162 set -e; \ 163 $(call cmd_genksyms, true) >/dev/null; \ 164 test -s $@ || rm -f $@ 165 166$(obj)/%.symtypes : $(src)/%.c FORCE 167 $(call cmd,cc_symtypes_c) 168 169# C (.c) files 170# The C file is compiled and updated dependency information is generated. 171# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 172 173quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 174 175ifndef CONFIG_MODVERSIONS 176cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 177 178else 179# When module versioning is enabled the following steps are executed: 180# o compile a .tmp_<file>.s from <file>.c 181# o if .tmp_<file>.s doesn't contain a __ksymtab version, i.e. does 182# not export symbols, we just assemble .tmp_<file>.s to <file>.o and 183# are done. 184# o otherwise, we calculate symbol versions using the good old 185# genksyms on the preprocessed source and postprocess them in a way 186# that they are usable as assembly source 187# o assemble <file>.o from .tmp_<file>.s forcing inclusion of directives 188# defining the actual values of __crc_*, followed by objcopy-ing them 189# to force these symbols to be local to permit stripping them later. 190s_file = $(@D)/.tmp_$(@F:.o=.s) 191v_file = $(@D)/.tmp_$(@F:.o=.v) 192tmp_o_file = $(@D)/.tmp_$(@F) 193no_g_c_flags = $(filter-out -g%,$(c_flags)) 194 195cmd_cc_o_c = $(CC) $(c_flags) -S -o $(s_file) $< 196 197cmd_modversions = \ 198 if grep -q __ksymtab $(s_file); then \ 199 if $(call cmd_genksyms, $(KBUILD_SYMTYPES)) > $(v_file) \ 200 && $(CC) $(no_g_c_flags) -c -Wa,$(v_file) \ 201 -o $(tmp_o_file) $(s_file) \ 202 && $(OBJCOPY) -L '__crc_*' -L '___crc_*' -w \ 203 $(tmp_o_file) $@; \ 204 then \ 205 : ; \ 206 else \ 207 rm -f $@; exit 1; \ 208 fi; \ 209 else \ 210 rm -f $(v_file); \ 211 $(CC) $(no_g_c_flags) -c -o $@ $(s_file); \ 212 fi; 213endif 214 215ifdef CONFIG_FTRACE_MCOUNT_RECORD 216cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ 217 "$(if $(CONFIG_64BIT),64,32)" \ 218 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC)" "$(LD)" "$(NM)" "$(RM)" "$(MV)" "$(@)"; 219endif 220 221define rule_cc_o_c 222 $(call echo-cmd,checksrc) $(cmd_checksrc) \ 223 $(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \ 224 $(cmd_modversions) \ 225 $(cmd_record_mcount) \ 226 scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \ 227 $(dot-target).tmp; \ 228 if [ -r $(@D)/.tmp_$(@F:.o=.v) ]; then \ 229 echo >> $(dot-target).tmp; \ 230 echo '$@: $(GENKSYMS)' >> $(dot-target).tmp; \ 231 echo '$(GENKSYMS):: ;' >> $(dot-target).tmp; \ 232 fi; \ 233 rm -f $(depfile) $(@D)/.tmp_$(@F:.o=.?); \ 234 mv -f $(dot-target).tmp $(dot-target).cmd 235endef 236 237# Built-in and composite module parts 238$(obj)/%.o: $(src)/%.c FORCE 239 $(call cmd,force_checksrc) 240 $(call if_changed_rule,cc_o_c) 241 242# Single-part modules are special since we need to mark them in $(MODVERDIR) 243 244$(single-used-m): $(obj)/%.o: $(src)/%.c FORCE 245 $(call cmd,force_checksrc) 246 $(call if_changed_rule,cc_o_c) 247 @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod) 248 249quiet_cmd_cc_lst_c = MKLST $@ 250 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 251 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 252 System.map $(OBJDUMP) > $@ 253 254$(obj)/%.lst: $(src)/%.c FORCE 255 $(call if_changed_dep,cc_lst_c) 256 257# Compile assembler sources (.S) 258# --------------------------------------------------------------------------- 259 260modkern_aflags := $(AFLAGS_KERNEL) 261 262$(real-objs-m) : modkern_aflags := $(AFLAGS_MODULE) 263$(real-objs-m:.o=.s): modkern_aflags := $(AFLAGS_MODULE) 264 265quiet_cmd_as_s_S = CPP $(quiet_modtag) $@ 266cmd_as_s_S = $(CPP) $(a_flags) -o $@ $< 267 268$(obj)/%.s: $(src)/%.S FORCE 269 $(call if_changed_dep,as_s_S) 270 271quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 272cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 273 274$(obj)/%.o: $(src)/%.S FORCE 275 $(call if_changed_dep,as_o_S) 276 277targets += $(real-objs-y) $(real-objs-m) $(lib-y) 278targets += $(extra-y) $(MAKECMDGOALS) $(always) 279 280# Linker scripts preprocessor (.lds.S -> .lds) 281# --------------------------------------------------------------------------- 282quiet_cmd_cpp_lds_S = LDS $@ 283 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -D__ASSEMBLY__ -o $@ $< 284 285$(obj)/%.lds: $(src)/%.lds.S FORCE 286 $(call if_changed_dep,cpp_lds_S) 287 288# Build the compiled-in targets 289# --------------------------------------------------------------------------- 290 291# To build objects in subdirs, we need to descend into the directories 292$(sort $(subdir-obj-y)): $(subdir-ym) ; 293 294# 295# Rule to compile a set of .o files into one .o file 296# 297ifdef builtin-target 298quiet_cmd_link_o_target = LD $@ 299# If the list of objects to link is empty, just create an empty built-in.o 300cmd_link_o_target = $(if $(strip $(obj-y)),\ 301 $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \ 302 $(cmd_secanalysis),\ 303 rm -f $@; $(AR) rcs $@) 304 305$(builtin-target): $(obj-y) FORCE 306 $(call if_changed,link_o_target) 307 308targets += $(builtin-target) 309endif # builtin-target 310 311# 312# Rule to create modules.order file 313# 314# Create commands to either record .ko file or cat modules.order from 315# a subdirectory 316modorder-cmds = \ 317 $(foreach m, $(modorder), \ 318 $(if $(filter %/modules.order, $m), \ 319 cat $m;, echo kernel/$m;)) 320 321$(modorder-target): $(subdir-ym) FORCE 322 $(Q)(cat /dev/null; $(modorder-cmds)) > $@ 323 324# 325# Rule to compile a set of .o files into one .a file 326# 327ifdef lib-target 328quiet_cmd_link_l_target = AR $@ 329cmd_link_l_target = rm -f $@; $(AR) rcs $@ $(lib-y) 330 331$(lib-target): $(lib-y) FORCE 332 $(call if_changed,link_l_target) 333 334targets += $(lib-target) 335endif 336 337# 338# Rule to link composite objects 339# 340# Composite objects are specified in kbuild makefile as follows: 341# <composite-object>-objs := <list of .o files> 342# or 343# <composite-object>-y := <list of .o files> 344link_multi_deps = \ 345$(filter $(addprefix $(obj)/, \ 346$($(subst $(obj)/,,$(@:.o=-objs))) \ 347$($(subst $(obj)/,,$(@:.o=-y)))), $^) 348 349quiet_cmd_link_multi-y = LD $@ 350cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) 351 352quiet_cmd_link_multi-m = LD [M] $@ 353cmd_link_multi-m = $(cmd_link_multi-y) 354 355# We would rather have a list of rules like 356# foo.o: $(foo-objs) 357# but that's not so easy, so we rather make all composite objects depend 358# on the set of all their parts 359$(multi-used-y) : %.o: $(multi-objs-y) FORCE 360 $(call if_changed,link_multi-y) 361 362$(multi-used-m) : %.o: $(multi-objs-m) FORCE 363 $(call if_changed,link_multi-m) 364 @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod) 365 366targets += $(multi-used-y) $(multi-used-m) 367 368 369# Descending 370# --------------------------------------------------------------------------- 371 372PHONY += $(subdir-ym) 373$(subdir-ym): 374 $(Q)$(MAKE) $(build)=$@ 375 376# Add FORCE to the prequisites of a target to force it to be always rebuilt. 377# --------------------------------------------------------------------------- 378 379PHONY += FORCE 380 381FORCE: 382 383# Read all saved command lines and dependencies for the $(targets) we 384# may be building above, using $(if_changed{,_dep}). As an 385# optimization, we don't need to read them if the target does not 386# exist, we will rebuild anyway in that case. 387 388targets := $(wildcard $(sort $(targets))) 389cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd)) 390 391ifneq ($(cmd_files),) 392 include $(cmd_files) 393endif 394 395 396# Declare the contents of the .PHONY variable as phony. We keep that 397# information in a variable se we can use it in if_changed and friends. 398 399.PHONY: $(PHONY) 400