Re: [Xen-devel] [XEN PATCH v2 09/12] xen/build: include include/config/auto.conf in main Makefile

[Jan Beulich <jbeulich@xxxxxxxx>]

On 03.02.2020 12:45, Anthony PERARD wrote:
> On Thu, Jan 30, 2020 at 02:06:18PM +0100, Jan Beulich wrote:
>> On 17.01.2020 11:53, Anthony PERARD wrote:
>>> --- a/xen/Makefile
>>> +++ b/xen/Makefile
>>> @@ -49,7 +49,71 @@ default: build
>>>  .PHONY: dist
>>>  dist: install
>>>  
>>> -build install:: include/config/auto.conf
>>> +
>>> +ifndef root-make-done
>>> +# section to run before calling Rules.mk, but only once.
>>> +#
>>> +# To make sure we do not include .config for any of the *config targets
>>> +# catch them early, and hand them over to tools/kconfig/Makefile
>>> +
>>> +clean-targets := %clean
>>> +no-dot-config-targets := $(clean-targets) \
>>> +                    uninstall debug cloc \
>>> +                    cscope TAGS tags MAP gtags \
>>> +                    xenversion
>>> +
>>> +config-build       :=
>>
>> Is this actually needed? While correct (afaict) together with the
>> ifdef further down, I find this aspect of make behavior a little
>> confusing, and hence it would seem slightly better if there was
>> no empty definition of this symbol.
> 
> That's actually a very recent change in Linux source code. They used to
> use ifeq($(config-build),1) and ifeq($(config-build),0). I can certainly
> change back to use ifeq instead of ifdef.

Then perhaps, along the lines of ...

>>> +need-config        := 1
>>
>> Here and below, would it be possible to use y instead of 1, to
>> match how "true" gets expressed in various places elsewhere?
>> Or would there again be deviation-from-Linux concerns?
> 
> It's probably fine to use "y". I don't think it matter, we need to make
> quite a lot of changes compare to Linux anyway. I'll use "n" for the
> negative.

... this, also use y/n?

>>> +ifdef config-build
>>> +# 
>>> ===========================================================================
>>> +# *config targets only - make sure prerequisites are updated, and descend
>>> +# in tools/kconfig to make the *config target
>>> +
>>> +config: FORCE
>>> +   $(MAKE) -f $(BASEDIR)/tools/kconfig/Makefile.kconfig ARCH=$(ARCH) 
>>> SRCARCH=$(SRCARCH) HOSTCC="$(HOSTCC)" HOSTCXX="$(HOSTCXX)" $@
>>> +
>>> +# Config.mk tries to include .config file, don't try to remake it
>>> +%/.config: ;
>>
>> This didn't exist before - why is it needed all of the sudden?
> 
> It's because I'm introducing a new target "%config". So when make
> "-include $(XEN_ROOT)/.config" (as found in Config.mk) it check if the
> file needs to be rebuilt, and find %config and thus run kconfig to build
> .config.
> 
> Currently, Makefile list all the targets that needs to be built with
> kconfig.

Ah, I see - we didn't have a %config target anywhere at all.

Jan

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel