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 := 25 26# Read .config if it exist, otherwise ignore 27-include include/config/auto.conf 28 29include scripts/Kbuild.include 30 31# The filename Kbuild has precedence over Makefile 32kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 33include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile) 34 35include scripts/Makefile.lib 36 37ifdef host-progs 38ifneq ($(hostprogs-y),$(host-progs)) 39$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!) 40hostprogs-y += $(host-progs) 41endif 42endif 43 44# Do not include host rules unles needed 45ifneq ($(hostprogs-y)$(hostprogs-m),) 46include scripts/Makefile.host 47endif 48 49ifneq ($(KBUILD_SRC),) 50# Create output directory if not already present 51_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj)) 52 53# Create directories for object files if directory does not exist 54# Needed when obj-y := dir/file.o syntax is used 55_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d))) 56endif 57 58ifndef obj 59$(warning kbuild: Makefile.build is included improperly) 60endif 61 62# =========================================================================== 63 64ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),) 65lib-target := $(obj)/lib.a 66endif 67 68ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(lib-target)),) 69builtin-target := $(obj)/built-in.o 70endif 71 72# We keep a list of all modules in $(MODVERDIR) 73 74__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ 75 $(if $(KBUILD_MODULES),$(obj-m)) \ 76 $(subdir-ym) $(always) 77 @: 78 79# Linus' kernel sanity checking tool 80ifneq ($(KBUILD_CHECKSRC),0) 81 ifeq ($(KBUILD_CHECKSRC),2) 82 quiet_cmd_force_checksrc = CHECK $< 83 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; 84 else 85 quiet_cmd_checksrc = CHECK $< 86 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; 87 endif 88endif 89 90 91# Compile C sources (.c) 92# --------------------------------------------------------------------------- 93 94# Default is built-in, unless we know otherwise 95modkern_cflags := $(CFLAGS_KERNEL) 96quiet_modtag := $(empty) $(empty) 97 98$(real-objs-m) : modkern_cflags := $(CFLAGS_MODULE) 99$(real-objs-m:.o=.i) : modkern_cflags := $(CFLAGS_MODULE) 100$(real-objs-m:.o=.s) : modkern_cflags := $(CFLAGS_MODULE) 101$(real-objs-m:.o=.lst): modkern_cflags := $(CFLAGS_MODULE) 102 103$(real-objs-m) : quiet_modtag := [M] 104$(real-objs-m:.o=.i) : quiet_modtag := [M] 105$(real-objs-m:.o=.s) : quiet_modtag := [M] 106$(real-objs-m:.o=.lst): quiet_modtag := [M] 107 108$(obj-m) : quiet_modtag := [M] 109 110# Default for not multi-part modules 111modname = $(basetarget) 112 113$(multi-objs-m) : modname = $(modname-multi) 114$(multi-objs-m:.o=.i) : modname = $(modname-multi) 115$(multi-objs-m:.o=.s) : modname = $(modname-multi) 116$(multi-objs-m:.o=.lst) : modname = $(modname-multi) 117$(multi-objs-y) : modname = $(modname-multi) 118$(multi-objs-y:.o=.i) : modname = $(modname-multi) 119$(multi-objs-y:.o=.s) : modname = $(modname-multi) 120$(multi-objs-y:.o=.lst) : modname = $(modname-multi) 121 122quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 123cmd_cc_s_c = $(CC) $(c_flags) -fverbose-asm -S -o $@ $< 124 125$(obj)/%.s: $(src)/%.c FORCE 126 $(call if_changed_dep,cc_s_c) 127 128quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@ 129cmd_cc_i_c = $(CPP) $(c_flags) -o $@ $< 130 131$(obj)/%.i: $(src)/%.c FORCE 132 $(call if_changed_dep,cc_i_c) 133 134quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ 135cmd_cc_symtypes_c = \ 136 $(CPP) -D__GENKSYMS__ $(c_flags) $< \ 137 | $(GENKSYMS) -T $@ >/dev/null; \ 138 test -s $@ || rm -f $@ 139 140$(obj)/%.symtypes : $(src)/%.c FORCE 141 $(call if_changed_dep,cc_symtypes_c) 142 143# C (.c) files 144# The C file is compiled and updated dependency information is generated. 145# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 146 147quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 148 149ifndef CONFIG_MODVERSIONS 150cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 151 152else 153# When module versioning is enabled the following steps are executed: 154# o compile a .tmp_<file>.o from <file>.c 155# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does 156# not export symbols, we just rename .tmp_<file>.o to <file>.o and 157# are done. 158# o otherwise, we calculate symbol versions using the good old 159# genksyms on the preprocessed source and postprocess them in a way 160# that they are usable as a linker script 161# o generate <file>.o from .tmp_<file>.o using the linker to 162# replace the unresolved symbols __crc_exported_symbol with 163# the actual value of the checksum generated by genksyms 164 165cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $< 166cmd_modversions = \ 167 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \ 168 $(CPP) -D__GENKSYMS__ $(c_flags) $< \ 169 | $(GENKSYMS) $(if $(KBUILD_SYMTYPES), \ 170 -T $(@D)/$(@F:.o=.symtypes)) -a $(ARCH) \ 171 > $(@D)/.tmp_$(@F:.o=.ver); \ 172 \ 173 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \ 174 -T $(@D)/.tmp_$(@F:.o=.ver); \ 175 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \ 176 else \ 177 mv -f $(@D)/.tmp_$(@F) $@; \ 178 fi; 179endif 180 181define rule_cc_o_c 182 $(call echo-cmd,checksrc) $(cmd_checksrc) \ 183 $(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \ 184 $(cmd_modversions) \ 185 scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \ 186 $(dot-target).tmp; \ 187 rm -f $(depfile); \ 188 mv -f $(dot-target).tmp $(dot-target).cmd 189endef 190 191# Built-in and composite module parts 192$(obj)/%.o: $(src)/%.c FORCE 193 $(call cmd,force_checksrc) 194 $(call if_changed_rule,cc_o_c) 195 196# Single-part modules are special since we need to mark them in $(MODVERDIR) 197 198$(single-used-m): $(obj)/%.o: $(src)/%.c FORCE 199 $(call cmd,force_checksrc) 200 $(call if_changed_rule,cc_o_c) 201 @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod) 202 203quiet_cmd_cc_lst_c = MKLST $@ 204 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 205 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 206 System.map $(OBJDUMP) > $@ 207 208$(obj)/%.lst: $(src)/%.c FORCE 209 $(call if_changed_dep,cc_lst_c) 210 211# Compile assembler sources (.S) 212# --------------------------------------------------------------------------- 213 214modkern_aflags := $(AFLAGS_KERNEL) 215 216$(real-objs-m) : modkern_aflags := $(AFLAGS_MODULE) 217$(real-objs-m:.o=.s): modkern_aflags := $(AFLAGS_MODULE) 218 219quiet_cmd_as_s_S = CPP $(quiet_modtag) $@ 220cmd_as_s_S = $(CPP) $(a_flags) -o $@ $< 221 222$(obj)/%.s: $(src)/%.S FORCE 223 $(call if_changed_dep,as_s_S) 224 225quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 226cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 227 228$(obj)/%.o: $(src)/%.S FORCE 229 $(call if_changed_dep,as_o_S) 230 231targets += $(real-objs-y) $(real-objs-m) $(lib-y) 232targets += $(extra-y) $(MAKECMDGOALS) $(always) 233 234# Linker scripts preprocessor (.lds.S -> .lds) 235# --------------------------------------------------------------------------- 236quiet_cmd_cpp_lds_S = LDS $@ 237 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -D__ASSEMBLY__ -o $@ $< 238 239$(obj)/%.lds: $(src)/%.lds.S FORCE 240 $(call if_changed_dep,cpp_lds_S) 241 242# Build the compiled-in targets 243# --------------------------------------------------------------------------- 244 245# To build objects in subdirs, we need to descend into the directories 246$(sort $(subdir-obj-y)): $(subdir-ym) ; 247 248# 249# Rule to compile a set of .o files into one .o file 250# 251ifdef builtin-target 252quiet_cmd_link_o_target = LD $@ 253# If the list of objects to link is empty, just create an empty built-in.o 254cmd_link_o_target = $(if $(strip $(obj-y)),\ 255 $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^),\ 256 rm -f $@; $(AR) rcs $@) 257 258$(builtin-target): $(obj-y) FORCE 259 $(call if_changed,link_o_target) 260 261targets += $(builtin-target) 262endif # builtin-target 263 264# 265# Rule to compile a set of .o files into one .a file 266# 267ifdef lib-target 268quiet_cmd_link_l_target = AR $@ 269cmd_link_l_target = rm -f $@; $(AR) rcs $@ $(lib-y) 270 271$(lib-target): $(lib-y) FORCE 272 $(call if_changed,link_l_target) 273 274targets += $(lib-target) 275endif 276 277# 278# Rule to link composite objects 279# 280# Composite objects are specified in kbuild makefile as follows: 281# <composite-object>-objs := <list of .o files> 282# or 283# <composite-object>-y := <list of .o files> 284link_multi_deps = \ 285$(filter $(addprefix $(obj)/, \ 286$($(subst $(obj)/,,$(@:.o=-objs))) \ 287$($(subst $(obj)/,,$(@:.o=-y)))), $^) 288 289quiet_cmd_link_multi-y = LD $@ 290cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) 291 292quiet_cmd_link_multi-m = LD [M] $@ 293cmd_link_multi-m = $(cmd_link_multi-y) 294 295# We would rather have a list of rules like 296# foo.o: $(foo-objs) 297# but that's not so easy, so we rather make all composite objects depend 298# on the set of all their parts 299$(multi-used-y) : %.o: $(multi-objs-y) FORCE 300 $(call if_changed,link_multi-y) 301 302$(multi-used-m) : %.o: $(multi-objs-m) FORCE 303 $(call if_changed,link_multi-m) 304 @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod) 305 306targets += $(multi-used-y) $(multi-used-m) 307 308 309# Descending 310# --------------------------------------------------------------------------- 311 312PHONY += $(subdir-ym) 313$(subdir-ym): 314 $(Q)$(MAKE) $(build)=$@ 315 316# Add FORCE to the prequisites of a target to force it to be always rebuilt. 317# --------------------------------------------------------------------------- 318 319PHONY += FORCE 320 321FORCE: 322 323# Read all saved command lines and dependencies for the $(targets) we 324# may be building above, using $(if_changed{,_dep}). As an 325# optimization, we don't need to read them if the target does not 326# exist, we will rebuild anyway in that case. 327 328targets := $(wildcard $(sort $(targets))) 329cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd)) 330 331ifneq ($(cmd_files),) 332 include $(cmd_files) 333endif 334 335 336# Declare the contents of the .PHONY variable as phony. We keep that 337# information in a variable se we can use it in if_changed and friends. 338 339.PHONY: $(PHONY) 340