# ==========================================================================
# Building
# ==========================================================================
src := $(obj)
PHONY := __build
__build:
# Init all relevant variables used in kbuild files so
# 1) they have correct type
# 2) they do not inherit any value from the environment
obj-y :=
obj-m :=
lib-y :=
lib-m :=
always :=
targets :=
subdir-y :=
subdir-m :=
EXTRA_AFLAGS :=
EXTRA_CFLAGS :=
EXTRA_CPPFLAGS :=
EXTRA_LDFLAGS :=
asflags-y :=
ccflags-y :=
cppflags-y :=
ldflags-y :=
# Read .config if it exist, otherwise ignore
-include include/config/auto.conf
include scripts/Kbuild.include
# For backward compatibility check that these variables does not change
save-cflags := $(CFLAGS)
# The filename Kbuild has precedence over Makefile
kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
include $(kbuild-file)
# If the save-* variables changed error out
ifeq ($(KBUILD_NOPEDANTIC),)
ifneq ("$(save-cflags)","$(CFLAGS)")
$(error CFLAGS was changed in "$(kbuild-file)". Fix it to use EXTRA_CFLAGS)
endif
endif
include scripts/Makefile.lib
ifdef host-progs
ifneq ($(hostprogs-y),$(host-progs))
$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
hostprogs-y += $(host-progs)
endif
endif
# Do not include host rules unles needed
ifneq ($(hostprogs-y)$(hostprogs-m),)
include scripts/Makefile.host
endif
ifneq ($(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
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
modorder-target := $(obj)/modules.order
# We keep a list of all modules in $(MODVERDIR)
__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
$(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
$(subdir-ym) $(always)
@:
# Linus' kernel sanity checking tool
ifneq ($(KBUILD_CHECKSRC),0)
ifeq ($(KBUILD_CHECKSRC),2)
quiet_cmd_force_checksrc = CHECK $<
cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
else
quiet_cmd_checksrc = CHECK $<
cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
endif
endif
# Do section mismatch analysis for each module/built-in.o
ifdef CONFIG_DEBUG_SECTION_MISMATCH
cmd_secanalysis = ; scripts/mod/modpost $@
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 = $(basetarget)
$(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) -fverbose-asm -S -o $@ $<
$(obj)/%.s: $(src)/%.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 $@ $<
$(obj)/%.i: $(src)/%.c FORCE
$(call if_changed_dep,cc_i_c)
quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
cmd_cc_symtypes_c = \
$(CPP) -D__GENKSYMS__ $(c_flags) $< \
| $(GENKSYMS) -T $@ >/dev/null; \
test -s $@ || rm -f $@
$(obj)/%.symtypes : $(src)/%.c FORCE
$(call if_changed_dep,cc_symtypes_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 \
$(CPP) -D__GENKSYMS__ $(c_flags) $< \
| $(GENKSYMS) $(if $(KBUILD_SYMTYPES), \
-T $(@D)/$(@F:.o=.symtypes)) -a $(ARCH) \
> $(@D)/.tmp_$(@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); \
else \
mv -f $(@D)/.tmp_$(@F) $@; \
fi;
endif
define rule_cc_o_c
$(call echo-cmd,checksrc) $(cmd_checksrc) \
$(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \
$(cmd_modversions) \
scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \
$(dot-target).tmp; \
rm -f $(depfile); \
mv -f $(dot-target).tmp $(dot-target).cmd
endef
# Built-in and composite module parts
$(obj)/%.o: $(src)/%.c FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
# Single-part modules are special since we need to mark them in $(MODVERDIR)
$(single-used-m): $(obj)/%.o: $(src)/%.c FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
@{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod)
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) > $@
$(obj)/%.lst: $(src)/%.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 $@ $<
$(obj)/%.s: $(src)/%.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 $@ $<
$(obj)/%.o: $(src)/%.S FORCE
$(call if_changed_dep,as_o_S)
targets += $(real-objs-y) $(real-objs-m) $(lib-y)
targets += $(extra-y) $(MAKECMDGOALS) $(always)
# Linker scripts preprocessor (.lds.S -> .lds)
# ---------------------------------------------------------------------------
quiet_cmd_cpp_lds_S = LDS $@
cmd_cpp_lds_S = $(CPP) $(cpp_flags) -D__ASSEMBLY__ -o $@ $<
$(obj)/%.lds: $(src)/%.lds.S FORCE
$(call if_changed_dep,cpp_lds_S)
# 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), $^) \
$(cmd_secanalysis),\
rm -f $@; $(AR) rcs $@)
$(builtin-target): $(obj-y) FORCE
$(call if_changed,link_o_target)
targets += $(builtin-target)
endif # builtin-target
#
# Rule to create modules.order file
#
# Create commands to either record .ko file or cat modules.order from
# a subdirectory
modorder-cmds = \
$(foreach m, $(modorder), \
$(if $(filter %/modules.order, $m), \
cat $m;, echo kernel/$m;))
$(modorder-target): $(subdir-ym) FORCE
$(Q)(cat /dev/null; $(modorder-cmds)) > $@
#
# 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) 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) $(cmd_secanalysis)
quiet_cmd_link_multi-m = LD [M] $@
cmd_link_multi-m = $(cmd_link_multi-y)
# 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)
@{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod)
targets += $(multi-used-y) $(multi-used-m)
# 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
# Declare the contents of the .PHONY variable as phony. We keep that
# information in a variable se we can use it in if_changed and friends.
.PHONY: $(PHONY)
