On Wed, May 11, 2022 at 5:05 AM Heiko Carstens <[email protected]> wrote:
>
> Commit ee6d777d3e93 ("s390/decompressor: support extra debug flags")
> added extra debug flags, in particular debug info is created,
> depending on config options.
>
> With llvm's IAS this causes this compile warning:
>
> arch/s390/boot/head.S:38:1: warning: DWARF2 only supports one section per compilation unit
> .section ".head.text","ax"
> ^
>
> This is a known problem and was addressed with a commit b8a9092330da
> ("Kbuild: do not emit debug info for assembly with LLVM_IAS=1").
> Just do the same for s390 to get rid of this warning.
>
> Signed-off-by: Heiko Carstens <[email protected]>
> ---
> arch/s390/Makefile | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/s390/Makefile b/arch/s390/Makefile
> index c59efc83f020..d73611b35164 100644
> --- a/arch/s390/Makefile
> +++ b/arch/s390/Makefile
> @@ -20,7 +20,9 @@ LDFLAGS_vmlinux := -pie
> endif
> aflags_dwarf := -Wa,-gdwarf-2
^ or can we use a more modern variant of dwarf, like at least dwarf-4?
> KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -D__ASSEMBLY__
> +ifndef CONFIG_AS_IS_LLVM
> KBUILD_AFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),$(aflags_dwarf))
> +endif
> KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack
> KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY
> KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float -mbackchain
> --
> 2.32.0
>
--
Thanks,
~Nick Desaulniers
On Wed, May 11, 2022 at 12:40:07PM -0700, Nick Desaulniers wrote:
> On Wed, May 11, 2022 at 5:05 AM Heiko Carstens <[email protected]> wrote:
> >
> > Commit ee6d777d3e93 ("s390/decompressor: support extra debug flags")
> > added extra debug flags, in particular debug info is created,
> > depending on config options.
> >
> > With llvm's IAS this causes this compile warning:
> >
> > arch/s390/boot/head.S:38:1: warning: DWARF2 only supports one section per compilation unit
> > .section ".head.text","ax"
> > ^
> >
> > This is a known problem and was addressed with a commit b8a9092330da
> > ("Kbuild: do not emit debug info for assembly with LLVM_IAS=1").
> > Just do the same for s390 to get rid of this warning.
> >
> > Signed-off-by: Heiko Carstens <[email protected]>
> > ---
> > arch/s390/Makefile | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/s390/Makefile b/arch/s390/Makefile
> > index c59efc83f020..d73611b35164 100644
> > --- a/arch/s390/Makefile
> > +++ b/arch/s390/Makefile
> > @@ -20,7 +20,9 @@ LDFLAGS_vmlinux := -pie
> > endif
> > aflags_dwarf := -Wa,-gdwarf-2
>
> ^ or can we use a more modern variant of dwarf, like at least dwarf-4?
For now I would like that this works the same like what you introduced
with commit b8a9092330da ("Kbuild: do not emit debug info for assembly
with LLVM_IAS=1").
I wouldn't like to have dwarf-4 enabled only for this single file, and
disabled for all other asm files (assuming that dwarf-4 works).