1# ========================================================================== 2# Building 3# ========================================================================== 4 5src := $(obj) 6 7.PHONY: __build 8__build: 9 10# Read .config if it exist, otherwise ignore 11-include .config 12 13include $(if $(wildcard $(obj)/Kbuild), $(obj)/Kbuild, $(obj)/Makefile) 14 15include scripts/Makefile.lib 16 17ifdef host-progs 18ifneq ($(hostprogs-y),$(host-progs)) 19$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!) 20hostprogs-y += $(host-progs) 21endif 22endif 23 24# Do not include host rules unles needed 25ifneq ($(hostprogs-y)$(hostprogs-m),) 26include scripts/Makefile.host 27endif 28 29ifneq ($(KBUILD_SRC),) 30# Create output directory if not already present 31_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj)) 32 33# Create directories for object files if directory does not exist 34# Needed when obj-y := dir/file.o syntax is used 35_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d))) 36endif 37 38 39ifdef EXTRA_TARGETS 40$(warning kbuild: $(obj)/Makefile - Usage of EXTRA_TARGETS is obsolete in 2.6. Please fix!) 41endif 42 43ifdef build-targets 44$(warning kbuild: $(obj)/Makefile - Usage of build-targets is obsolete in 2.6. Please fix!) 45endif 46 47ifdef export-objs 48$(warning kbuild: $(obj)/Makefile - Usage of export-objs is obsolete in 2.6. Please fix!) 49endif 50 51ifdef O_TARGET 52$(warning kbuild: $(obj)/Makefile - Usage of O_TARGET := $(O_TARGET) is obsolete in 2.6. Please fix!) 53endif 54 55ifdef L_TARGET 56$(error kbuild: $(obj)/Makefile - Use of L_TARGET is replaced by lib-y in 2.6. Please fix!) 57endif 58 59ifdef list-multi 60$(warning kbuild: $(obj)/Makefile - list-multi := $(list-multi) is obsolete in 2.6. Please fix!) 61endif 62 63ifndef obj 64$(warning kbuild: Makefile.build is included improperly) 65endif 66 67# =========================================================================== 68 69ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),) 70lib-target := $(obj)/lib.a 71endif 72 73ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(lib-target)),) 74builtin-target := $(obj)/built-in.o 75endif 76 77# We keep a list of all modules in $(MODVERDIR) 78 79__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \ 80 $(if $(KBUILD_MODULES),$(obj-m)) \ 81 $(subdir-ym) $(always) 82 @: 83 84# Linus' kernel sanity checking tool 85ifneq ($(KBUILD_CHECKSRC),0) 86 ifeq ($(KBUILD_CHECKSRC),2) 87 quiet_cmd_force_checksrc = CHECK $< 88 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; 89 else 90 quiet_cmd_checksrc = CHECK $< 91 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ; 92 endif 93endif 94 95 96# Compile C sources (.c) 97# --------------------------------------------------------------------------- 98 99# Default is built-in, unless we know otherwise 100modkern_cflags := $(CFLAGS_KERNEL) 101quiet_modtag := $(empty) $(empty) 102 103$(real-objs-m) : modkern_cflags := $(CFLAGS_MODULE) 104$(real-objs-m:.o=.i) : modkern_cflags := $(CFLAGS_MODULE) 105$(real-objs-m:.o=.s) : modkern_cflags := $(CFLAGS_MODULE) 106$(real-objs-m:.o=.lst): modkern_cflags := $(CFLAGS_MODULE) 107 108$(real-objs-m) : quiet_modtag := [M] 109$(real-objs-m:.o=.i) : quiet_modtag := [M] 110$(real-objs-m:.o=.s) : quiet_modtag := [M] 111$(real-objs-m:.o=.lst): quiet_modtag := [M] 112 113$(obj-m) : quiet_modtag := [M] 114 115# Default for not multi-part modules 116modname = $(*F) 117 118$(multi-objs-m) : modname = $(modname-multi) 119$(multi-objs-m:.o=.i) : modname = $(modname-multi) 120$(multi-objs-m:.o=.s) : modname = $(modname-multi) 121$(multi-objs-m:.o=.lst) : modname = $(modname-multi) 122$(multi-objs-y) : modname = $(modname-multi) 123$(multi-objs-y:.o=.i) : modname = $(modname-multi) 124$(multi-objs-y:.o=.s) : modname = $(modname-multi) 125$(multi-objs-y:.o=.lst) : modname = $(modname-multi) 126 127quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ 128cmd_cc_s_c = $(CC) $(c_flags) -S -o $@ $< 129 130%.s: %.c FORCE 131 $(call if_changed_dep,cc_s_c) 132 133quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@ 134cmd_cc_i_c = $(CPP) $(c_flags) -o $@ $< 135 136%.i: %.c FORCE 137 $(call if_changed_dep,cc_i_c) 138 139# C (.c) files 140# The C file is compiled and updated dependency information is generated. 141# (See cmd_cc_o_c + relevant part of rule_cc_o_c) 142 143quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ 144 145ifndef CONFIG_MODVERSIONS 146cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< 147 148else 149# When module versioning is enabled the following steps are executed: 150# o compile a .tmp_<file>.o from <file>.c 151# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does 152# not export symbols, we just rename .tmp_<file>.o to <file>.o and 153# are done. 154# o otherwise, we calculate symbol versions using the good old 155# genksyms on the preprocessed source and postprocess them in a way 156# that they are usable as a linker script 157# o generate <file>.o from .tmp_<file>.o using the linker to 158# replace the unresolved symbols __crc_exported_symbol with 159# the actual value of the checksum generated by genksyms 160 161cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $< 162cmd_modversions = \ 163 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \ 164 $(CPP) -D__GENKSYMS__ $(c_flags) $< \ 165 | $(GENKSYMS) \ 166 > $(@D)/.tmp_$(@F:.o=.ver); \ 167 \ 168 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \ 169 -T $(@D)/.tmp_$(@F:.o=.ver); \ 170 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \ 171 else \ 172 mv $(@D)/.tmp_$(@F) $@; \ 173 fi; 174endif 175 176define rule_cc_o_c 177 $(if $($(quiet)cmd_checksrc),echo ' $($(quiet)cmd_checksrc)';) \ 178 $(cmd_checksrc) \ 179 $(if $($(quiet)cmd_cc_o_c),echo ' $($(quiet)cmd_cc_o_c)';) \ 180 $(cmd_cc_o_c); \ 181 $(cmd_modversions) \ 182 scripts/basic/fixdep $(depfile) $@ '$(cmd_cc_o_c)' > $(@D)/.$(@F).tmp; \ 183 rm -f $(depfile); \ 184 mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd 185endef 186 187# Built-in and composite module parts 188 189%.o: %.c FORCE 190 $(call cmd,force_checksrc) 191 $(call if_changed_rule,cc_o_c) 192 193# Single-part modules are special since we need to mark them in $(MODVERDIR) 194 195$(single-used-m): %.o: %.c FORCE 196 $(call cmd,force_checksrc) 197 $(call if_changed_rule,cc_o_c) 198 @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod) 199 200quiet_cmd_cc_lst_c = MKLST $@ 201 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ 202 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ 203 System.map $(OBJDUMP) > $@ 204 205%.lst: %.c FORCE 206 $(call if_changed_dep,cc_lst_c) 207 208# Compile assembler sources (.S) 209# --------------------------------------------------------------------------- 210 211modkern_aflags := $(AFLAGS_KERNEL) 212 213$(real-objs-m) : modkern_aflags := $(AFLAGS_MODULE) 214$(real-objs-m:.o=.s): modkern_aflags := $(AFLAGS_MODULE) 215 216quiet_cmd_as_s_S = CPP $(quiet_modtag) $@ 217cmd_as_s_S = $(CPP) $(a_flags) -o $@ $< 218 219%.s: %.S FORCE 220 $(call if_changed_dep,as_s_S) 221 222quiet_cmd_as_o_S = AS $(quiet_modtag) $@ 223cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< 224 225%.o: %.S FORCE 226 $(call if_changed_dep,as_o_S) 227 228targets += $(real-objs-y) $(real-objs-m) $(lib-y) 229targets += $(extra-y) $(MAKECMDGOALS) $(always) 230 231# Linker scripts preprocessor (.lds.S -> .lds) 232# --------------------------------------------------------------------------- 233quiet_cmd_cpp_lds_S = LDS $@ 234 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -D__ASSEMBLY__ -o $@ $< 235 236%.lds: %.lds.S FORCE 237 $(call if_changed_dep,cpp_lds_S) 238 239# Build the compiled-in targets 240# --------------------------------------------------------------------------- 241 242# To build objects in subdirs, we need to descend into the directories 243$(sort $(subdir-obj-y)): $(subdir-ym) ; 244 245# 246# Rule to compile a set of .o files into one .o file 247# 248ifdef builtin-target 249quiet_cmd_link_o_target = LD $@ 250# If the list of objects to link is empty, just create an empty built-in.o 251cmd_link_o_target = $(if $(strip $(obj-y)),\ 252 $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^),\ 253 rm -f $@; $(AR) rcs $@) 254 255$(builtin-target): $(obj-y) FORCE 256 $(call if_changed,link_o_target) 257 258targets += $(builtin-target) 259endif # builtin-target 260 261# 262# Rule to compile a set of .o files into one .a file 263# 264ifdef lib-target 265quiet_cmd_link_l_target = AR $@ 266cmd_link_l_target = rm -f $@; $(AR) $(EXTRA_ARFLAGS) rcs $@ $(lib-y) 267 268$(lib-target): $(lib-y) FORCE 269 $(call if_changed,link_l_target) 270 271targets += $(lib-target) 272endif 273 274# 275# Rule to link composite objects 276# 277# Composite objects are specified in kbuild makefile as follows: 278# <composite-object>-objs := <list of .o files> 279# or 280# <composite-object>-y := <list of .o files> 281link_multi_deps = \ 282$(filter $(addprefix $(obj)/, \ 283$($(subst $(obj)/,,$(@:.o=-objs))) \ 284$($(subst $(obj)/,,$(@:.o=-y)))), $^) 285 286quiet_cmd_link_multi-y = LD $@ 287cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) 288 289quiet_cmd_link_multi-m = LD [M] $@ 290cmd_link_multi-m = $(LD) $(ld_flags) $(LDFLAGS_MODULE) -o $@ $(link_multi_deps) 291 292# We would rather have a list of rules like 293# foo.o: $(foo-objs) 294# but that's not so easy, so we rather make all composite objects depend 295# on the set of all their parts 296$(multi-used-y) : %.o: $(multi-objs-y) FORCE 297 $(call if_changed,link_multi-y) 298 299$(multi-used-m) : %.o: $(multi-objs-m) FORCE 300 $(call if_changed,link_multi-m) 301 @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod) 302 303targets += $(multi-used-y) $(multi-used-m) 304 305 306# Descending 307# --------------------------------------------------------------------------- 308 309.PHONY: $(subdir-ym) 310$(subdir-ym): 311 $(Q)$(MAKE) $(build)=$@ 312 313# Add FORCE to the prequisites of a target to force it to be always rebuilt. 314# --------------------------------------------------------------------------- 315 316.PHONY: FORCE 317 318FORCE: 319 320# Read all saved command lines and dependencies for the $(targets) we 321# may be building above, using $(if_changed{,_dep}). As an 322# optimization, we don't need to read them if the target does not 323# exist, we will rebuild anyway in that case. 324 325targets := $(wildcard $(sort $(targets))) 326cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd)) 327 328ifneq ($(cmd_files),) 329 include $(cmd_files) 330endif 331