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39808e451f
Since commit040fcc819a("kbuild: improved modversioning support for external modules"), the external module build reads Module.symvers in the directory of the module itself, then dumps symbols back into it. It accumulates stale symbols in the file when you build an external module incrementally. The idea behind it was, as the commit log explained, you can copy Modules.symvers from one module to another when you need to pass symbol information between two modules. However, the manual copy of the file sounds questionable to me, and containing stale symbols is a downside. Some time later, commit0d96fb20b7("kbuild: Add new Kbuild variable KBUILD_EXTRA_SYMBOLS") introduced a saner approach. So, this commit removes the former one. Going forward, the external module build dumps symbols into Module.symvers to be carried via KBUILD_EXTRA_SYMBOLS, but never reads it automatically. With the -I option removed, there is no one to set the external_module flag unless KBUILD_EXTRA_SYMBOLS is passed. Now the -i option does it instead. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
104 lines
3.3 KiB
Makefile
104 lines
3.3 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# ===========================================================================
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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 which is the .o files above linked together
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# c) A <module>.mod file, listing the name of the preliminary <module>.o file,
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# plus all .o files
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# d) modules.order, which lists all the modules
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# Stage 2 is handled by this file and does the following
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# 1) Find all modules listed in modules.order
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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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# 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/linux/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[_RT]
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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.symvers file.
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# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
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# symbols in the final module linking stage
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# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
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# This is solely useful to speed up test compiles
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PHONY := __modpost
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__modpost:
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include include/config/auto.conf
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include scripts/Kbuild.include
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kernelsymfile := $(objtree)/Module.symvers
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modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
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MODPOST = scripts/mod/modpost \
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$(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 $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \
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$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
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$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
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$(if $(KBUILD_MODPOST_WARN),-w) \
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$(if $(filter nsdeps,$(MAKECMDGOALS)),-d)
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ifdef MODPOST_VMLINUX
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quiet_cmd_modpost = MODPOST vmlinux.o
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cmd_modpost = $(MODPOST) vmlinux.o
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__modpost:
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$(call cmd,modpost)
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else
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MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s -T -
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ifeq ($(KBUILD_EXTMOD),)
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MODPOST += $(wildcard vmlinux)
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else
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# set src + obj - they may be used in the modules's Makefile
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obj := $(KBUILD_EXTMOD)
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src := $(obj)
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# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
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include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
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$(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
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endif
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# find all modules listed in modules.order
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modules := $(sort $(shell cat $(MODORDER)))
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# Read out modules.order instead of expanding $(modules) to pass in modpost.
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# Otherwise, allmodconfig would fail with "Argument list too long".
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quiet_cmd_modpost = MODPOST $(words $(modules)) modules
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cmd_modpost = sed 's/ko$$/o/' $(MODORDER) | $(MODPOST)
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__modpost:
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@$(kecho) ' Building modules, stage 2.'
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$(call cmd,modpost)
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ifneq ($(KBUILD_MODPOST_NOFINAL),1)
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$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
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endif
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nsdeps: __modpost
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endif
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.PHONY: $(PHONY)
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