741f98fe29
Previously we did do the check on the .o files used to link vmlinux but that failed to find questionable references across the .o files. Create a dedicated vmlinux.o file used only for section mismatch checks that uses the defualt linker script so section does not get renamed. The vmlinux.o may later be used as part of the the final link of vmlinux but for now it is used fo section mismatch only. For a defconfig build this is instant but for an allyesconfig this add two minutes to a full build (that anyways takes ~2 hours). Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
132 lines
4.4 KiB
Makefile
132 lines
4.4 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 which 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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# 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 usefull to speed up test compiles
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PHONY := _modpost
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_modpost: __modpost
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include include/config/auto.conf
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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 := $(firstword $(KBUILD_EXTMOD))/Module.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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# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
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_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(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 $(words $(filter-out vmlinux FORCE, $^)) modules
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cmd_modpost = scripts/mod/modpost \
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$(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 $(modulesymfile)) \
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$(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
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PHONY += __modpost
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__modpost: $(modules:.ko=.o) FORCE
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$(call cmd,modpost) $(wildcard vmlinux) $(filter-out FORCE,$^)
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quiet_cmd_kernel-mod = MODPOST $@
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cmd_kernel-mod = $(cmd_modpost) $@
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PHONY += vmlinux
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vmlinux.o: FORCE
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$(call cmd,kernel-mod)
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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 = $(notdir $(@:.mod.o=))
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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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# Declare the contents of the .PHONY variable as phony. We keep that
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# information in a variable se we can use it in if_changed and friends.
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.PHONY: $(PHONY)
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