scripts/Makefile.build

# ==========================================================================
# Building
# ==========================================================================

src := $(obj)

.PHONY: __build
__build:

# Read .config if it exist, otherwise ignore
-include .config

include $(obj)/Makefile

include scripts/Makefile.lib

ifneq ($(KBUILD_SRC),)
# Create output directory if not already present
_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))

# Create directories for object files if directory does not exist
# Needed when obj-y := dir/file.o syntax is used
_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
endif


ifdef EXTRA_TARGETS
$(warning kbuild: $(obj)/Makefile - Usage of EXTRA_TARGETS is obsolete in 2.6. Please fix!)
endif

ifdef build-targets
$(warning kbuild: $(obj)/Makefile - Usage of build-targets is obsolete in 2.6. Please fix!)
endif

ifdef export-objs
$(warning kbuild: $(obj)/Makefile - Usage of export-objs is obsolete in 2.6. Please fix!)
endif

ifdef O_TARGET
$(warning kbuild: $(obj)/Makefile - Usage of O_TARGET := $(O_TARGET) is obsolete in 2.6. Please fix!)
endif

ifdef L_TARGET
$(error kbuild: $(obj)/Makefile - Use of L_TARGET is replaced by lib-y in 2.6. Please fix!)
endif

ifdef list-multi
$(warning kbuild: $(obj)/Makefile - list-multi := $(list-multi) is obsolete in 2.6. Please fix!)
endif

ifndef obj
$(warning kbuild: Makefile.build is included improperly)
endif

# ===========================================================================

ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),)
lib-target := $(obj)/lib.a
endif

ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(lib-target)),)
builtin-target := $(obj)/built-in.o
endif

# We keep a list of all modules in $(MODVERDIR)

touch-module = @echo $(@:.o=.ko) > $(MODVERDIR)/$(@F:.o=.mod)

__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
	 $(if $(KBUILD_MODULES),$(obj-m)) \
	 $(subdir-ym) $(always)
	@:

# Linus' kernel sanity checking tool
ifneq ($(KBUILD_CHECKSRC),0)
quiet_cmd_checksrc = CHECK   $<
      cmd_checksrc = $(CHECK) $(c_flags) $< ;
endif


# Compile C sources (.c)
# ---------------------------------------------------------------------------

# Default is built-in, unless we know otherwise
modkern_cflags := $(CFLAGS_KERNEL)
quiet_modtag := $(empty)   $(empty)

$(real-objs-m)        : modkern_cflags := $(CFLAGS_MODULE)
$(real-objs-m:.o=.i)  : modkern_cflags := $(CFLAGS_MODULE)
$(real-objs-m:.o=.s)  : modkern_cflags := $(CFLAGS_MODULE)
$(real-objs-m:.o=.lst): modkern_cflags := $(CFLAGS_MODULE)

$(real-objs-m)        : quiet_modtag := [M]
$(real-objs-m:.o=.i)  : quiet_modtag := [M]
$(real-objs-m:.o=.s)  : quiet_modtag := [M]
$(real-objs-m:.o=.lst): quiet_modtag := [M]

$(obj-m)              : quiet_modtag := [M]

# Default for not multi-part modules
modname = $(*F)

$(multi-objs-m)         : modname = $(modname-multi)
$(multi-objs-m:.o=.i)   : modname = $(modname-multi)
$(multi-objs-m:.o=.s)   : modname = $(modname-multi)
$(multi-objs-m:.o=.lst) : modname = $(modname-multi)
$(multi-objs-y)         : modname = $(modname-multi)
$(multi-objs-y:.o=.i)   : modname = $(modname-multi)
$(multi-objs-y:.o=.s)   : modname = $(modname-multi)
$(multi-objs-y:.o=.lst) : modname = $(modname-multi)

quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
cmd_cc_s_c       = $(CC) $(c_flags) -S -o $@ $< 

%.s: %.c FORCE
	$(call if_changed_dep,cc_s_c)

quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@
cmd_cc_i_c       = $(CPP) $(c_flags)   -o $@ $<

%.i: %.c FORCE
	$(call if_changed_dep,cc_i_c)

# C (.c) files
# The C file is compiled and updated dependency information is generated.
# (See cmd_cc_o_c + relevant part of rule_cc_o_c)

quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@

ifndef CONFIG_MODVERSIONS
cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<

else
# When module versioning is enabled the following steps are executed:
# o compile a .tmp_<file>.o from <file>.c
# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
#   not export symbols, we just rename .tmp_<file>.o to <file>.o and
#   are done.
# o otherwise, we calculate symbol versions using the good old
#   genksyms on the preprocessed source and postprocess them in a way
#   that they are usable as a linker script
# o generate <file>.o from .tmp_<file>.o using the linker to
#   replace the unresolved symbols __crc_exported_symbol with
#   the actual value of the checksum generated by genksyms

cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
cmd_modversions =							\
	if ! $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then	\
		mv $(@D)/.tmp_$(@F) $@;					\
	else								\
		$(CPP) -D__GENKSYMS__ $(c_flags) $<			\
		| $(GENKSYMS)						\
		> $(@D)/.tmp_$(@F:.o=.ver);				\
									\
		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 		\
			-T $(@D)/.tmp_$(@F:.o=.ver);			\
		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);	\
	fi;
endif

define rule_cc_o_c
	$(if $($(quiet)cmd_checksrc),echo '  $($(quiet)cmd_checksrc)';)   \
	$(cmd_checksrc)							  \
	$(if $($(quiet)cmd_cc_o_c),echo '  $($(quiet)cmd_cc_o_c)';)	  \
	$(cmd_cc_o_c);							  \
	$(cmd_modversions)						  \
	scripts/fixdep $(depfile) $@ '$(cmd_cc_o_c)' > $(@D)/.$(@F).tmp;  \
	rm -f $(depfile);						  \
	mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd
endef

# Built-in and composite module parts

%.o: %.c FORCE
	$(call if_changed_rule,cc_o_c)

# Single-part modules are special since we need to mark them in $(MODVERDIR)

$(single-used-m): %.o: %.c FORCE
	$(call if_changed_rule,cc_o_c)
	$(touch-module)

quiet_cmd_cc_lst_c = MKLST   $@
      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
				     System.map $(OBJDUMP) > $@

%.lst: %.c FORCE
	$(call if_changed_dep,cc_lst_c)

# Compile assembler sources (.S)
# ---------------------------------------------------------------------------

modkern_aflags := $(AFLAGS_KERNEL)

$(real-objs-m)      : modkern_aflags := $(AFLAGS_MODULE)
$(real-objs-m:.o=.s): modkern_aflags := $(AFLAGS_MODULE)

quiet_cmd_as_s_S = CPP $(quiet_modtag) $@
cmd_as_s_S       = $(CPP) $(a_flags)   -o $@ $< 

%.s: %.S FORCE
	$(call if_changed_dep,as_s_S)

quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
cmd_as_o_S       = $(CC) $(a_flags) -c -o $@ $<

%.o: %.S FORCE
	$(call if_changed_dep,as_o_S)

targets += $(real-objs-y) $(real-objs-m) $(lib-y)
targets += $(extra-y) $(MAKECMDGOALS) $(always)

# Build the compiled-in targets
# ---------------------------------------------------------------------------

# To build objects in subdirs, we need to descend into the directories
$(sort $(subdir-obj-y)): $(subdir-ym) ;

#
# Rule to compile a set of .o files into one .o file
#
ifdef builtin-target
quiet_cmd_link_o_target = LD      $@
# If the list of objects to link is empty, just create an empty built-in.o
cmd_link_o_target = $(if $(strip $(obj-y)),\
		      $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^),\
		      rm -f $@; $(AR) rcs $@)

$(builtin-target): $(obj-y) FORCE
	$(call if_changed,link_o_target)

targets += $(builtin-target)
endif # builtin-target

#
# Rule to compile a set of .o files into one .a file
#
ifdef lib-target
quiet_cmd_link_l_target = AR      $@
cmd_link_l_target = rm -f $@; $(AR) $(EXTRA_ARFLAGS) rcs $@ $(lib-y)

$(lib-target): $(lib-y) FORCE
	$(call if_changed,link_l_target)

targets += $(lib-target)
endif

#
# Rule to link composite objects
#
#  Composite objects are specified in kbuild makefile as follows:
#    <composite-object>-objs := <list of .o files>
#  or
#    <composite-object>-y    := <list of .o files>
link_multi_deps =                     \
$(filter $(addprefix $(obj)/,         \
$($(subst $(obj)/,,$(@:.o=-objs)))    \
$($(subst $(obj)/,,$(@:.o=-y)))), $^)
 
quiet_cmd_link_multi-y = LD      $@
cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps)

quiet_cmd_link_multi-m = LD [M]  $@
cmd_link_multi-m = $(LD) $(ld_flags) $(LDFLAGS_MODULE) -o $@ $(link_multi_deps)

# We would rather have a list of rules like
# 	foo.o: $(foo-objs)
# but that's not so easy, so we rather make all composite objects depend
# on the set of all their parts
$(multi-used-y) : %.o: $(multi-objs-y) FORCE
	$(call if_changed,link_multi-y)

$(multi-used-m) : %.o: $(multi-objs-m) FORCE
	$(call if_changed,link_multi-m)
	$(touch-module)

targets += $(multi-used-y) $(multi-used-m)

# Compile programs on the host
# ===========================================================================
# host-progs := bin2hex
# Will compile bin2hex.c and create an executable named bin2hex
#
# host-progs    := lxdialog
# lxdialog-objs := checklist.o lxdialog.o
# Will compile lxdialog.c and checklist.c, and then link the executable
# lxdialog, based on checklist.o and lxdialog.o
#
# host-progs      := qconf
# qconf-cxxobjs   := qconf.o
# qconf-objs      := menu.o
# Will compile qconf as a C++ program, and menu as a C program.
# They are linked as C++ code to the executable qconf

# host-progs := conf
# conf-objs  := conf.o libkconfig.so
# libkconfig-objs := expr.o type.o
# Will create a shared library named libkconfig.so that consist of
# expr.o and type.o (they are both compiled as C code and the object file
# are made as position independent code).
# conf.c is compiled as a c program, and conf.o is linked together with
# libkconfig.so as the executable conf.
# Note: Shared libraries consisting of C++ files are not supported  
#

# Create executable from a single .c file
# host-csingle -> Executable
quiet_cmd_host-csingle 	= HOSTCC  $@
      cmd_host-csingle	= $(HOSTCC) $(hostc_flags) $(HOST_LOADLIBES) -o $@ $<
$(host-csingle): %: %.c FORCE
	$(call if_changed_dep,host-csingle)

# Link an executable based on list of .o files, all plain c
# host-cmulti -> executable
quiet_cmd_host-cmulti	= HOSTLD  $@
      cmd_host-cmulti	= $(HOSTCC) $(HOSTLDFLAGS) -o $@ \
			  $(addprefix $(obj)/,$($(@F)-objs)) \
			  $(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))
$(host-cmulti): %: $(host-cobjs) $(host-cshlib) FORCE
	$(call if_changed,host-cmulti)

# Create .o file from a single .c file
# host-cobjs -> .o
quiet_cmd_host-cobjs	= HOSTCC  $@
      cmd_host-cobjs	= $(HOSTCC) $(hostc_flags) -c -o $@ $<
$(host-cobjs): %.o: %.c FORCE
	$(call if_changed_dep,host-cobjs)

# Link an executable based on list of .o files, a mixture of .c and .cc
# host-cxxmulti -> executable
quiet_cmd_host-cxxmulti	= HOSTLD  $@
      cmd_host-cxxmulti	= $(HOSTCXX) $(HOSTLDFLAGS) -o $@ \
			  $(foreach o,objs cxxobjs,\
			  $(addprefix $(obj)/,$($(@F)-$(o)))) \
			  $(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))
$(host-cxxmulti): %: $(host-cobjs) $(host-cxxobjs) $(host-cshlib) FORCE
	$(call if_changed,host-cxxmulti)

# Create .o file from a single .cc (C++) file
quiet_cmd_host-cxxobjs	= HOSTCXX $@
      cmd_host-cxxobjs	= $(HOSTCXX) $(hostcxx_flags) -c -o $@ $<
$(host-cxxobjs): %.o: %.cc FORCE
	$(call if_changed_dep,host-cxxobjs)

# Compile .c file, create position independent .o file
# host-cshobjs -> .o
quiet_cmd_host-cshobjs	= HOSTCC  -fPIC $@
      cmd_host-cshobjs	= $(HOSTCC) $(hostc_flags) -fPIC -c -o $@ $<
$(host-cshobjs): %.o: %.c FORCE
	$(call if_changed_dep,host-cshobjs)

# Link a shared library, based on position independent .o files
# *.o -> .so shared library (host-cshlib)
quiet_cmd_host-cshlib	= HOSTLLD -shared $@
      cmd_host-cshlib	= $(HOSTCC) $(HOSTLDFLAGS) -shared -o $@ \
			  $(addprefix $(obj)/,$($(@F:.so=-objs))) \
			  $(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))
$(host-cshlib): %: $(host-cshobjs) FORCE
	$(call if_changed,host-cshlib)

targets += $(host-csingle)  $(host-cmulti) $(host-cobjs)\
	   $(host-cxxmulti) $(host-cxxobjs) $(host-cshlib) $(host-cshobjs) 

# Descending
# ---------------------------------------------------------------------------

.PHONY: $(subdir-ym)
$(subdir-ym):
	$(Q)$(MAKE) $(build)=$@

# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------

.PHONY: FORCE

FORCE:

# Read all saved command lines and dependencies for the $(targets) we
# may be building above, using $(if_changed{,_dep}). As an
# optimization, we don't need to read them if the target does not
# exist, we will rebuild anyway in that case.

targets := $(wildcard $(sort $(targets)))
cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))

ifneq ($(cmd_files),)
  include $(cmd_files)
endif