On Wed, 2023-02-01 at 11:00 +0100, Marc Hartmayer wrote:
> Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx> writes:
>
> > On Thu, 2023-01-19 at 12:40 +0100, Marc Hartmayer wrote:
> > > Use the C pre-processor for the linker script generation. For example,
> > > this enables us the use of constants in the "linker scripts" `*.lds.S`.
> > >
> > > Signed-off-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx>
> > > ---
> > > .gitignore | 1 +
> > > s390x/Makefile | 6 ++++--
> > > s390x/{flat.lds => flat.lds.S} | 0
> > > s390x/snippets/asm/{flat.lds => flat.lds.S} | 0
> > > s390x/snippets/c/{flat.lds => flat.lds.S} | 0
> > > 5 files changed, 5 insertions(+), 2 deletions(-)
> > > rename s390x/{flat.lds => flat.lds.S} (100%)
> > > rename s390x/snippets/asm/{flat.lds => flat.lds.S} (100%)
> > > rename s390x/snippets/c/{flat.lds => flat.lds.S} (100%)
> > >
> > > diff --git a/.gitignore b/.gitignore
> > > index 601822d67325..29f352c5ceb6 100644
> > > --- a/.gitignore
> > > +++ b/.gitignore
> > > @@ -31,3 +31,4 @@ cscope.*
> > > /s390x/comm.key
> > > /s390x/snippets/*/*.hdr
> > > /s390x/snippets/*/*.*obj
> > > +/s390x/**/*.lds
> > > diff --git a/s390x/Makefile b/s390x/Makefile
> > > index 8719f0c837cf..44ccca8102d6 100644
> > > --- a/s390x/Makefile
> > > +++ b/s390x/Makefile
> > > @@ -76,7 +76,7 @@ CFLAGS += -fno-delete-null-pointer-checks
> > > LDFLAGS += -nostdlib -Wl,--build-id=none
> > >
> > > # We want to keep intermediate files
> > > -.PRECIOUS: %.o
> > > +.PRECIOUS: %.o %.lds
> > >
> > > asm-offsets = lib/$(ARCH)/asm-offsets.h
> > > include $(SRCDIR)/scripts/asm-offsets.mak
> > > @@ -159,6 +159,8 @@ $(SNIPPET_DIR)/c/%.gbin: $(SNIPPET_DIR)/c/%.o $(snippet_lib) $(FLATLIBS) $(SNIPP
> > > %.hdr.obj: %.hdr
> > > $(OBJCOPY) -I binary -O elf64-s390 -B "s390:64-bit" $< $@
> > >
> > > +%.lds: %.lds.S
> > > + $(CPP) $(autodepend-flags) $(CPPFLAGS) -P -C -o $@ $<
> >
> > Where is CPP defined?
> > Do you need the $(autodepend-flags)? It generates a rule with target flat.lds.o.
> ^^^^^^^^^^
>
> Where does it generate a new Makefile rule? It generates the dependency
> file used for the dependency tracking with the name: .flat.lds.S.d (or
> similar)
Yes and that file contains the rule.
cat s390x/.flat.d
flat.lds.o: /foo/bar/s390x/flat.lds.S \
/foo/bar/lib/asm/asm-offsets.h \
/foo/bar/lib/generated/asm-offsets.h
>
> > I don't think that would be used anywhere.
>
> It’s used for the dependency tracking. See line
>
> $KUT/Makefile:122
>
> -include */.*.d */*/.*.d
Indeed, but the target flat.lds.o isn't used anywhere, is it?
So if flat.lds.S included some other header and that changed,
flat.lds wouldn't be rebuild.
So you would either need to generate a rule with flat.lds as target
or make it depend on flat.lds.o somehow.
>
> > In the next patch you add $(asm-offsets) as a prerequisite, if the generated rule would
> > be effective, you wouldn't need that, would you?
>
> I thought, $(asm-offsets) is used to make sure that the file
> <asm/asm-offsets.h> is generated.
I was asking if this is necessary, since s390x/.flat.d contains the asm-offset headers
as prerequisites. So if the dependency file is included, the headers will be build,
but I guess that this is circular, in order to generate the dependencies,
the asm-offset headers must already have been built.
>
> […snip]
>
