On Fri, Dec 15, 2023 at 5:56 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
>
> On Fri, Dec 15, 2023 at 04:45:49PM -0800, Alexei Starovoitov wrote:
> > From: Alexei Starovoitov <ast@xxxxxxxxxx>
> >
> > The func_addr used to be NULL for indirect trampolines used by struct_ops.
> > Now func_addr is a valid function pointer.
> > Hence use BPF_TRAMP_F_INDIRECT flag to detect such condition.
> >
> > Fixes: 2cd3e3772e41 ("x86/cfi,bpf: Fix bpf_struct_ops CFI")
> > Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> > ---
> > arch/s390/net/bpf_jit_comp.c | 3 ++-
> > tools/testing/selftests/bpf/DENYLIST.s390x | 2 --
> > 2 files changed, 2 insertions(+), 3 deletions(-)
>
> IIUC F_INDIRECT trampolines are called via C function pointers, and
> func_addr does not participate in any call chains, but is rather used
> as a source of CFI information.
Yes.
> So returning to %r14 is the right
> thing to do.
>
> Thanks!
>
> Reviewed-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Thank you for the quick review.
