Re: [PATCH] kbuild: take into account DT_SCHEMA_FILES changes while checking dtbs

[Dmitry Baryshkov]

On 16/09/2022 17:54, Rob Herring wrote:
> On Fri, Sep 16, 2022 at 9:21 AM Dmitry Baryshkov
> <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > On Fri, 16 Sept 2022 at 04:10, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> > > On Thu, Sep 15, 2022 at 8:40 PM Dmitry Baryshkov
> > > <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > > > On Thu, 15 Sept 2022 at 07:51, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> > > > > On Sun, Sep 11, 2022 at 2:36 AM Dmitry Baryshkov
> > > > >
> > > > > <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > > > > > On Thu, 4 Aug 2022 at 18:27, Rob Herring <robh+dt@xxxxxxxxxx> wrote:
> > > > > > > On Fri, Jul 29, 2022 at 1:46 AM Dmitry Baryshkov
> > > > > > > <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > > > > > > > On Fri, 29 Jul 2022 at 10:05, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> > > > > > > > > On Fri, Jul 29, 2022 at 3:53 PM Dmitry Baryshkov
> > > > > > > > > <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > > > > > > > > > On Fri, 29 Jul 2022 at 08:55, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> > > > > > > > > > > On Thu, Jul 28, 2022 at 2:36 AM Rob Herring <robh+dt@xxxxxxxxxx> wrote:
> > > > > > > > > > > > On Wed, Jul 27, 2022 at 4:06 AM Dmitry Baryshkov
> > > > > > > > > > > > <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > > > > > > > > > > > > It is useful to be able to recheck dtbs files against a limited set of
> > > > > > > > > > > > > DT schema files. This can be accomplished by using differnt
> > > > > > > > > > > > > DT_SCHEMA_FILES argument values while rerunning make dtbs_check. However
> > > > > > > > > > > > > for some reason if_changed_rule doesn't pick up the rule_dtc changes
> > > > > > > > > > > > > (and doesn't retrigger the build).
> > > > > > > > > > > > >
> > > > > > > > > > > > > Fix this by changing if_changed_rule to if_changed_dep and squashing DTC
> > > > > > > > > > > > > and dt-validate into a single new command. Then if_changed_dep triggers
> > > > > > > > > > > > > on DT_SCHEMA_FILES changes and reruns the build/check.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > > > > > > > > > > > > ---
> > > > > > > > > > > > >   scripts/Makefile.lib | 14 ++++++--------
> > > > > > > > > > > > >   1 file changed, 6 insertions(+), 8 deletions(-)
> > > > > > > > > > > > >
> > > > > > > > > > > > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> > > > > > > > > > > > > index c88b98b5dc44..3df470289382 100644
> > > > > > > > > > > > > --- a/scripts/Makefile.lib
> > > > > > > > > > > > > +++ b/scripts/Makefile.lib
> > > > > > > > > > > > > @@ -383,17 +383,15 @@ DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),-l $(DT_SCHEMA_FILES),-m)
> > > > > > > > > > > > >   DT_BINDING_DIR := Documentation/devicetree/bindings
> > > > > > > > > > > > >   DT_TMP_SCHEMA := $(objtree)/$(DT_BINDING_DIR)/processed-schema.json
> > > > > > > > > > > > >
> > > > > > > > > > > > > -quiet_cmd_dtb_check =  CHECK   $@
> > > > > > > > > > > > > -      cmd_dtb_check =  $(DT_CHECKER) $(DT_CHECKER_FLAGS) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@ || true
> > > > > > > > > > > > > +quiet_cmd_dtb =        DTC/CHECK   $@
> > > > > > > > > > > >
> > > > > > > > > > > > This is supposed to be 7 chars or less. DTCCHK or DTC_CHK perhaps. Or
> > > > > > > > > > > > always do just 'DTC'. I can fixup when applying.
> > > > > > > > > > > >
> > > > > > > > > > > > I'll give it a few days for other comments.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > When you change DT_SCHEMA_FILES, re-running dt-validate should be enough.
> > > > > > > > > > > You do not need to re-run dtc.
> > > > > > > > > > >
> > > > > > > > > > > I guess the strangeness comes from the fact that you are trying to do the
> > > > > > > > > > >   two different things in a single rule.
> > > > > > > > > >
> > > > > > > > > > The issue is that with the current rules the dt-validate isn't
> > > > > > > > > > re-executed on DT_SCHEMA_FILES changes. Thus comes my proposal.
> > > > > > > > >
> > > > > > > > > Correct.
> > > > > > > > >
> > > > > > > > > What I said is like this.
> > > > > > > > >
> > > > > > > > > # touch the timestamp file, %.dtb.checked
> > > > > > > > > $(obj)/%.dtb.checked: $(obj)/%.dtb $(DT_TMP_SCHEMA) FORCE
> > > > > > >
> > > > > > > Not really a fan of the thousands of files that creates. Maybe if it
> > > > > > > was turned into something useful like a list of schemas that apply to
> > > > > > > the dtb. IOW, a dependency list. That would speed up re-running after
> > > > > > > a schema change. Though if a schema change created new dependencies,
> > > > > > > that wouldn't work.
> > > > > > >
> > > > > > > > >          $(call if_changed_rule,dtb_check)
> > > > > > > > >
> > > > > > > > > $(obj)/%.dtb: $(src)/%.dts $(DTC) $FORCE
> > > > > > > > >          $(call if_changed_rule,dtc)
> > > > > > > > >
> > > > > > > > > $(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
> > > > > > > > >          $(call if_changed_dep,dtc)
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > With the dtc/check split, we can avoid unneeded regeneration of
> > > > > > > > > %.dtb when DT_TMP_SCHEMA or DT_SCHEMA_FILES is
> > > > > > > > > changed.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > One drawback is we track %.dtb.checked and and %.dtb separately,
> > > > > > > > > so something like 53182e81f47d4ea0c727c49ad23cb782173ab849
> > > > > > > > > may come back.
> > > > > > > >
> > > > > > > > It's up to you and Rob, but I'd really prefer a simpler solution here.
> > > > > > > > Regenerating dtbs sounds like a minor pain compared to hacking the
> > > > > > > > top-level Makefile again. What I really like is that if one has
> > > > > > > > CHECK_DTBS=y (for whatever reason), he can not generate dtb without
> > > > > > > > validation.
> > > > > > >
> > > > > > > I lean towards just rebuilding the dtbs. That's pretty quick and
> > > > > > > ensures we get dtc warnings with schema warnings. In the long run, I
> > > > > > > would like to make the schema checks not optional to run. The
> > > > > > > impediment to doing that is lots of warnings (but not not some
> > > > > > > platforms), adding a tool dependency, and validation time.
> > > > > >
> > > > > > Rob, Masahiro, do we have any conclusion here? I can change my patch,
> > > > > > but I'd like to understand in which way I should change it.
> > > > > > Fixing/testing yaml changes is a bit painful w/o this change.
> > > > > >
> > > > > > --
> > > > > > With best wishes
> > > > > > Dmitry
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > I am fine with the patch as long as you fix DTC/CHECK to DTC.
> > > >
> > > > Ack, I completely forgot about this part. Please excuse me. I'll
> > > > change it to DTC_CHK (as suggested before) to fit into 7 chars in v2.
> > > >
> > > > > Another idea is to re-check the schema every time,
> > > > > like this:
> > > >
> > > > I think this will add the external build dependency. We tried a
> > > > similar approach several releases ago and had to revert the change.
> > >
> > >
> > > If you are talking about
> > > 75e895343d5a2fcbdf4cb3d31ab7492bd65925f0,
> > > you are completely misunderstanding.
> > >
> > > Look at my code closely.
> > > It is how the sparse checker works with C=2.
> >
> > Ah, I see. Then I'm fine with either your patch or mine v2 at your
> > (and Rob's) preference.
>
> I'd rather not recheck every time. The user can remove the dtbs if
> they want to do that.

Then [1] should be the better fit.

[1] 
https://lore.kernel.org/linux-kernel/20220915114422.79378-1-dmitry.baryshkov@xxxxxxxxxx/

--
With best wishes
Dmitry