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# ===========================================================================
# Module versions
# ===========================================================================
#
# Stage one of module building created the following:
# a) The individual .o files used for the module
# b) A <module>.o file which is the .o files above linked together
# c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
# the preliminary <module>.o file, plus all .o files
# Stage 2 is handled by this file and does the following
# 1) Find all modules from the files listed in $(MODVERDIR)/
# 2) modpost is then used to
# 3) create one <module>.mod.c file pr. module
# 4) create one Module.symvers file with CRC for all exported symbols
# 5) compile all <module>.mod.c files
# 6) final link of the module to a <module.ko> file
# Step 3 is used to place certain information in the module's ELF
# section, including information such as:
# Version magic (see include/vermagic.h for full details)
# - Kernel release
# - SMP is CONFIG_SMP
# - PREEMPT is CONFIG_PREEMPT
# - GCC Version
# Module info
# - Module version (MODULE_VERSION)
# - Module alias'es (MODULE_ALIAS)
# - Module license (MODULE_LICENSE)
# - See include/linux/module.h for more details
# Step 4 is solely used to allow module versioning in external modules,
# where the CRC of each module is retrieved from the Module.symers file.
PHONY := _modpost
_modpost: __modpost
include include/config/auto.conf
include scripts/Kbuild.include
include scripts/Makefile.lib
kernelsymfile := $(objtree)/Module.symvers
modulesymfile := $(KBUILD_EXTMOD)/Module.symvers
# Step 1), find all modules listed in $(MODVERDIR)/
__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
_modpost: $(modules)
# Step 2), invoke modpost
# Includes step 3,4
quiet_cmd_modpost = MODPOST
cmd_modpost = scripts/mod/modpost \
$(if $(CONFIG_MODVERSIONS),-m) \
$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \
$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
$(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
$(filter-out FORCE,$^)
PHONY += __modpost
__modpost: $(wildcard vmlinux) $(modules:.ko=.o) FORCE
$(call cmd,modpost)
# Declare generated files as targets for modpost
$(symverfile): __modpost ;
$(modules:.ko=.mod.c): __modpost ;
# Step 5), compile all *.mod.c files
# modname is set to make c_flags define KBUILD_MODNAME
modname = $(notdir $(@:.mod.o=))
quiet_cmd_cc_o_c = CC $@
cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE) \
-c -o $@ $<
$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
$(call if_changed_dep,cc_o_c)
targets += $(modules:.ko=.mod.o)
# Step 6), final link of the modules
quiet_cmd_ld_ko_o = LD [M] $@
cmd_ld_ko_o = $(LD) $(LDFLAGS) $(LDFLAGS_MODULE) -o $@ \
$(filter-out FORCE,$^)
$(modules): %.ko :%.o %.mod.o FORCE
$(call if_changed,ld_ko_o)
targets += $(modules)
# 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)
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