040fcc819a
With following patch a second option is enabled to obtain symbol information from a second external module when a external module is build. The recommended approach is to use a common kbuild file but that may be impractical in certain cases. With this patch one can copy over a Module.symvers from one external module to make symbols (and symbol versions) available for another external module. Updated documentation in Documentation/kbuild/modules.txt Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
115 lines
3.6 KiB
Makefile
115 lines
3.6 KiB
Makefile
# ===========================================================================
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# Module versions
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# ===========================================================================
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#
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# Stage one of module building created the following:
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# a) The individual .o files used for the module
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# b) A <module>.o file wich is the .o files above linked together
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# c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
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# the preliminary <module>.o file, plus all .o files
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# Stage 2 is handled by this file and does the following
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# 1) Find all modules from the files listed in $(MODVERDIR)/
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# 2) modpost is then used to
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# 3) create one <module>.mod.c file pr. module
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# 4) create one Module.symvers file with CRC for all exported symbols
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# 5) compile all <module>.mod.c files
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# 6) final link of the module to a <module.ko> file
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# Step 3 is used to place certain information in the module's ELF
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# section, including information such as:
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# Version magic (see include/vermagic.h for full details)
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# - Kernel release
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# - SMP is CONFIG_SMP
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# - PREEMPT is CONFIG_PREEMPT
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# - GCC Version
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# Module info
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# - Module version (MODULE_VERSION)
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# - Module alias'es (MODULE_ALIAS)
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# - Module license (MODULE_LICENSE)
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# - See include/linux/module.h for more details
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# Step 4 is solely used to allow module versioning in external modules,
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# where the CRC of each module is retrieved from the Module.symers file.
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.PHONY: _modpost
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_modpost: __modpost
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include .config
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include scripts/Kbuild.include
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include scripts/Makefile.lib
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kernelsymfile := $(objtree)/Module.symvers
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modulesymfile := $(KBUILD_EXTMOD)/Modules.symvers
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# Step 1), find all modules listed in $(MODVERDIR)/
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__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
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modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
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_modpost: $(modules)
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# Step 2), invoke modpost
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# Includes step 3,4
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quiet_cmd_modpost = MODPOST
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cmd_modpost = scripts/mod/modpost \
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$(if $(CONFIG_MODVERSIONS),-m) \
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$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \
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$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
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$(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
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$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
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$(filter-out FORCE,$^)
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.PHONY: __modpost
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__modpost: $(wildcard vmlinux) $(modules:.ko=.o) FORCE
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$(call cmd,modpost)
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# Declare generated files as targets for modpost
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$(symverfile): __modpost ;
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$(modules:.ko=.mod.c): __modpost ;
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# Step 5), compile all *.mod.c files
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# modname is set to make c_flags define KBUILD_MODNAME
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modname = $(*F)
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quiet_cmd_cc_o_c = CC $@
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cmd_cc_o_c = $(CC) $(c_flags) $(CFLAGS_MODULE) \
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-c -o $@ $<
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$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
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$(call if_changed_dep,cc_o_c)
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targets += $(modules:.ko=.mod.o)
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# Step 6), final link of the modules
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quiet_cmd_ld_ko_o = LD [M] $@
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cmd_ld_ko_o = $(LD) $(LDFLAGS) $(LDFLAGS_MODULE) -o $@ \
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$(filter-out FORCE,$^)
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$(modules): %.ko :%.o %.mod.o FORCE
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$(call if_changed,ld_ko_o)
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targets += $(modules)
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# Add FORCE to the prequisites of a target to force it to be always rebuilt.
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# ---------------------------------------------------------------------------
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.PHONY: FORCE
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FORCE:
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# Read all saved command lines and dependencies for the $(targets) we
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# may be building above, using $(if_changed{,_dep}). As an
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# optimization, we don't need to read them if the target does not
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# exist, we will rebuild anyway in that case.
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targets := $(wildcard $(sort $(targets)))
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cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
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ifneq ($(cmd_files),)
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include $(cmd_files)
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endif
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