[kvm-unit-tests PATCH v1] s390x: explicitly mark stack as not executable

[kvm-unit-tests PATCH v1] s390x: explicitly mark stack as not executable

[Nico Boehr]

With somewhat recent GCC versions, we get this warning on s390x:

  /usr/bin/ld: warning: s390x/cpu.o: missing .note.GNU-stack section implies executable stack
  /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker

We don't really care whether stack is executable or not since we set it
up ourselves and we're running DAT off mostly anyways.

Silence the warning by explicitly marking the stack as not executable.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
 s390x/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/s390x/Makefile b/s390x/Makefile
index 706be7920406..afa47ccbeb93 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -79,7 +79,7 @@ CFLAGS += -O2
 CFLAGS += -march=zEC12
 CFLAGS += -mbackchain
 CFLAGS += -fno-delete-null-pointer-checks
-LDFLAGS += -nostdlib -Wl,--build-id=none
+LDFLAGS += -nostdlib -Wl,--build-id=none -z noexecstack
 
 # We want to keep intermediate files
 .PRECIOUS: %.o %.lds
-- 
2.41.0

Re: [kvm-unit-tests PATCH v1] s390x: explicitly mark stack as not executable

[Claudio Imbrenda]

On Wed,  9 Aug 2023 11:17:08 +0200
Nico Boehr <nrb@linux.ibm.com> wrote:

> With somewhat recent GCC versions, we get this warning on s390x:
> 
>   /usr/bin/ld: warning: s390x/cpu.o: missing .note.GNU-stack section implies executable stack
>   /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
> 
> We don't really care whether stack is executable or not since we set it
> up ourselves and we're running DAT off mostly anyways.
> 
> Silence the warning by explicitly marking the stack as not executable.
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

> ---
>  s390x/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/s390x/Makefile b/s390x/Makefile
> index 706be7920406..afa47ccbeb93 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -79,7 +79,7 @@ CFLAGS += -O2
>  CFLAGS += -march=zEC12
>  CFLAGS += -mbackchain
>  CFLAGS += -fno-delete-null-pointer-checks
> -LDFLAGS += -nostdlib -Wl,--build-id=none
> +LDFLAGS += -nostdlib -Wl,--build-id=none -z noexecstack
>  
>  # We want to keep intermediate files
>  .PRECIOUS: %.o %.lds

Re: [kvm-unit-tests PATCH v1] s390x: explicitly mark stack as not executable

[Thomas Huth]

On 09/08/2023 11.17, Nico Boehr wrote:
> With somewhat recent GCC versions, we get this warning on s390x:
> 
>    /usr/bin/ld: warning: s390x/cpu.o: missing .note.GNU-stack section implies executable stack
>    /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
> 
> We don't really care whether stack is executable or not since we set it
> up ourselves and we're running DAT off mostly anyways.
> 
> Silence the warning by explicitly marking the stack as not executable.
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
> ---
>   s390x/Makefile | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/s390x/Makefile b/s390x/Makefile
> index 706be7920406..afa47ccbeb93 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -79,7 +79,7 @@ CFLAGS += -O2
>   CFLAGS += -march=zEC12
>   CFLAGS += -mbackchain
>   CFLAGS += -fno-delete-null-pointer-checks
> -LDFLAGS += -nostdlib -Wl,--build-id=none
> +LDFLAGS += -nostdlib -Wl,--build-id=none -z noexecstack

I already did a similar patch some weeks ago:

  https://lore.kernel.org/kvm/20230623125416.481755-1-thuth@redhat.com/

... we need it for x86, too, so I guess I should go ahead and commit it - 
and ask Sean to respin his conflicting series.

  Thomas

Re: [kvm-unit-tests PATCH v1] s390x: explicitly mark stack as not executable

[Nico Boehr]

Quoting Thomas Huth (2023-08-13 11:50:00)
> On 09/08/2023 11.17, Nico Boehr wrote:
> > With somewhat recent GCC versions, we get this warning on s390x:
> > 
> >    /usr/bin/ld: warning: s390x/cpu.o: missing .note.GNU-stack section implies executable stack
> >    /usr/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
> > 
> > We don't really care whether stack is executable or not since we set it
> > up ourselves and we're running DAT off mostly anyways.
> > 
> > Silence the warning by explicitly marking the stack as not executable.
> > 
> > Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
> > ---
> >   s390x/Makefile | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/s390x/Makefile b/s390x/Makefile
> > index 706be7920406..afa47ccbeb93 100644
> > --- a/s390x/Makefile
> > +++ b/s390x/Makefile
> > @@ -79,7 +79,7 @@ CFLAGS += -O2
> >   CFLAGS += -march=zEC12
> >   CFLAGS += -mbackchain
> >   CFLAGS += -fno-delete-null-pointer-checks
> > -LDFLAGS += -nostdlib -Wl,--build-id=none
> > +LDFLAGS += -nostdlib -Wl,--build-id=none -z noexecstack
> 
> I already did a similar patch some weeks ago:
> 
>   https://lore.kernel.org/kvm/20230623125416.481755-1-thuth@redhat.com/
> 
> ... we need it for x86, too, so I guess I should go ahead and commit it - 
> and ask Sean to respin his conflicting series.

Thanks!