[PATCH v6 02/14] aarch64: configure test for BTI support

[H.J. Lu]

On Tue, Jul 7, 2020 at 9:59 AM Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>
> The 07/07/2020 07:39, H.J. Lu wrote:
> > On Tue, Jul 7, 2020 at 7:27 AM Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
> > > i don't know how to reliably link with gcc start files
> > > but not with libc start files.
> > >
> > > explicit link wiht crtbeginS.o may not be right, the
> > > exact name depends on the compiler driver.
> > >
> > > so i would have to provide dummy libc start files to be
> > > able to do the check, but that can go bad in many ways
> > > so the check may not be reliable.
> >
> > For CET, I added --enable-cet to enable CET in GCC run-time,
> > including crtbeginS.o, ...  Since CET enabled run-time is backward
> > compatible, it is safe to do so.  In fact, --enable-cet is the default
> > starting from GCC 10.
>
> makes sense.
>
> on aarch64, bti needs a recent binutils otherwise
> there are ugly linker warnings for the unknown gnu
> properties so i don't think it's a good idea to
> turn it on by default just yet.

config/cet.m4 has --enable-cet=auto.   CET is enabled only
if binutuls supports CET.


-- 
H.J.