Hi Arnd,
2016-07-06 22:49 GMT+09:00 Arnd Bergmann <arnd@xxxxxxxx>:
>>
>>
>> The dependency "tinyconfig: $(obj)/conf" is redundant.
>>
>>
>> It is already specified by:
>>
>> allnoconfig allyesconfig allmodconfig alldefconfig randconfig: $(obj)/conf
>> $< --$@ $(Kconfig)
>
>
> I don't see that yet. How does this line provide the dependency?
"make tinyconfig" works like this:
[1] In the top Makefile, Kbuild handles "make tinyconfig"
with the following rule:
%config: scripts_basic outputmakefile FORCE
$(Q)$(MAKE) $(build)=scripts/kconfig $@
So, Kbuild will descend into scripts/kconfig.
[2] In scripts/kconfig/Makefile, Kbuild handles "make tinyconfig"
with the following rule:
tinyconfig:
$(Q)$(MAKE) -f $(srctree)/Makefile allnoconfig tiny.config
-f $(srctree)/Makefile means "use the top Makefile".
So, Kbuild will go back to the top Makefile and run "make allnoconfig
tiny.config" there.
[3] In the top Makefile, Kbuild handles "make allnoconfig tiny.config"
with the following rule (mixed targets):
__build_one_by_one:
$(Q)set -e; \
for i in $(MAKECMDGOALS); do \
$(MAKE) -f $(srctree)/Makefile $$i; \
done
This means, run "make allnoconfig", then "make tiny.config"
in this order.
[4] In the top Makefile, Kbuild handles "make allnoconfig"
with the following rule:
%config: scripts_basic outputmakefile FORCE
$(Q)$(MAKE) $(build)=scripts/kconfig $@
Kbuild will descend into scripts/kconfig.
[5] In scripts/kconfig/Makefile, Kbuild handles "make allnoconfig"
with the following rule:
simple-targets := oldconfig allnoconfig allyesconfig allmodconfig \
alldefconfig randconfig listnewconfig olddefconfig
PHONY += $(simple-targets)
$(simple-targets): $(obj)/conf
$< $(silent) --$@ $(Kconfig)
At this point, $(obj)/conf is generated and then, Kbuild runs allnoconfig.
[6] In the top Makefile, Kbuild handles "make tiny.config"
with the following rule:
%config: scripts_basic outputmakefile FORCE
$(Q)$(MAKE) $(build)=scripts/kconfig $@
Kbuild will descend into scripts/kconfig.
[7] In scripts/kconfig/Makefile, Kbuild handles "make tiny.config"
with the following rule:
%.config: $(obj)/conf
$(if $(call configfiles),, $(error No configuration exists for
this target on this architecture))
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh
-m .config $(configfiles)
+$(Q)yes "" | $(MAKE) -f $(srctree)/Makefile oldconfig
I hope this is helpful.
>
> So, let's ignore my incorrect patch for the moment. Do you have
> any other idea for how to avoid the warning?
Of your four ideas, I do not like the first two,
but the others sound reasonable.
> - merge the fragments first and then use the combined fragment as the
> KCONFIG_ALLCONFIG file.
This is a strait-forward solution.
I thought of this one, too.
> - change merge_config.sh to do a 'savedefconfig' step before applying
> the fragment, so it doesn't warn about choice statements that are
> overridden from their default, as opposed to having conflicting choices.
This sounds interesting.
BTW, I have been wondering if we could support merge_config
as a native feature of Kconfig instead of by a separate shell script.
If we could support KCONFIG_ALLCONFIG for "make oldconfig"
perhaps merge_config.sh will go away?
Maybe I am missing something, though.
--
Best Regards
Masahiro Yamada
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