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