Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.36 as permitted sender) client-ip=23.128.96.36;
MIME-Version: 1.0
References: <20231018151950.205265-1-masahiroy@kernel.org> <20231018151950.205265-4-masahiroy@kernel.org>
 <ZTDlrkTXnkVN1cff@krava>
In-Reply-To: <ZTDlrkTXnkVN1cff@krava>
From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
Date:   Thu, 19 Oct 2023 15:54:52 -0700
Message-ID: <CAEf4BzZm4h4q6k9ZhuT5qiWC9PYA+c7XwVFd68iAq4mtMJ-qhw@mail.gmail.com>
Subject: Re: [bpf-next PATCH v2 4/4] kbuild: refactor module BTF rule
To:     Jiri Olsa <olsajiri@gmail.com>
Cc:     Masahiro Yamada <masahiroy@kernel.org>,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>, bpf@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, Oct 19, 2023 at 1:15=E2=80=AFAM Jiri Olsa <olsajiri@gmail.com> wrot=
e:
>
> On Thu, Oct 19, 2023 at 12:19:50AM +0900, Masahiro Yamada wrote:
> > newer_prereqs_except and if_changed_except are ugly hacks of the
> > newer-prereqs and if_changed in scripts/Kbuild.include.
> >
> > Remove.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> > ---
> >
> > Changes in v2:
> >   - Fix if_changed_except to if_changed
> >
> >  scripts/Makefile.modfinal | 25 ++++++-------------------
> >  1 file changed, 6 insertions(+), 19 deletions(-)
> >
> > diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
> > index 9fd7a26e4fe9..fc07854bb7b9 100644
> > --- a/scripts/Makefile.modfinal
> > +++ b/scripts/Makefile.modfinal
> > @@ -19,6 +19,9 @@ vmlinux :=3D
> >  ifdef CONFIG_DEBUG_INFO_BTF_MODULES
> >  ifneq ($(wildcard vmlinux),)
> >  vmlinux :=3D vmlinux
> > +cmd_btf =3D ; \
> > +     LLVM_OBJCOPY=3D"$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_ba=
se vmlinux $@; \
> > +     $(RESOLVE_BTFIDS) -b vmlinux $@
> >  else
> >  $(warning Skipping BTF generation due to unavailability of vmlinux)
> >  endif
> > @@ -41,27 +44,11 @@ quiet_cmd_ld_ko_o =3D LD [M]  $@
> >        cmd_ld_ko_o +=3D                                                =
 \
> >       $(LD) -r $(KBUILD_LDFLAGS)                                      \
> >               $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE)              \
> > -             -T scripts/module.lds -o $@ $(filter %.o, $^)
> > +             -T scripts/module.lds -o $@ $(filter %.o, $^)           \
> > +     $(cmd_btf)
> >
> > -quiet_cmd_btf_ko =3D BTF [M] $@
>
> nit not sure it's intentional but we no longer display 'BTF [M] ...ko' li=
nes,
> I don't mind not displaying that, but we should mention that in changelog
>

Thanks for spotting this! I think those messages are useful and
important to keep. Masahiro, is it possible to preserve them?


> jirka
>
> > -      cmd_btf_ko =3D                                                  =
 \
> > -             LLVM_OBJCOPY=3D"$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) =
--btf_base vmlinux $@; \
> > -             $(RESOLVE_BTFIDS) -b vmlinux $@
> > -
> > -# Same as newer-prereqs, but allows to exclude specified extra depende=
ncies
> > -newer_prereqs_except =3D $(filter-out $(PHONY) $(1),$?)
> > -
> > -# Same as if_changed, but allows to exclude specified extra dependenci=
es
> > -if_changed_except =3D $(if $(call newer_prereqs_except,$(2))$(cmd-chec=
k),      \
> > -     $(cmd);                                                          =
    \
> > -     printf '%s\n' 'savedcmd_$@ :=3D $(make-cmd)' > $(dot-target).cmd,=
 @:)
> > -
> > -# Re-generate module BTFs if either module's .ko or vmlinux changed
> >  %.ko: %.o %.mod.o scripts/module.lds $(vmlinux) FORCE
> > -     +$(call if_changed_except,ld_ko_o,vmlinux)
> > -ifdef vmlinux
> > -     +$(if $(newer-prereqs),$(call cmd,btf_ko))
> > -endif
> > +     +$(call if_changed,ld_ko_o)
> >
> >  targets +=3D $(modules:%.o=3D%.ko) $(modules:%.o=3D%.mod.o)
> >
> > --
> > 2.40.1
> >
> >
>