Re: PING: [PATCH] i386: Add __x86_indirect_thunk_nt_reg for -fcf-protection -mcet

[Jan Hubicka <hubicka at ucw dot cz>]

> On Fri, Feb 2, 2018 at 8:54 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> > nocf_check attribute can be used with -fcf-protection -mcet to disable
> > control-flow check by adding NOTRACK prefix before indirect branch.
> > When -mindirect-branch=thunk-extern -mindirect-branch-register is added,
> > indirect branch via register, "notrack call/jmp reg", is converted to
> >
> >     call/jmp __x86_indirect_thunk_nt_reg
> >
> > When running on machines with CET enabled, __x86_indirect_thunk_nt_reg
> > can be updated to
> >
> >     notrack jmp reg
> >
> > at run-time to restore NOTRACK prefix in the original indirect branch.
> >
> > Since we don't support -mindirect-branch=thunk-extern, CET and MPX at
> > the same time, -mindirect-branch=thunk-extern is disallowed with
> > -fcf-protection=branch and -fcheck-pointer-bounds.
> >
> > Tested on i686 and x86-64.  OK for trunk?
> >
> > Thanks.
> >
> > H.J.
> > ---
> > gcc/
> >
> >         PR target/84176
> >         * config/i386/i386.c (ix86_set_indirect_branch_type): Issue an
> >         error when -mindirect-branch=thunk-extern, -fcf-protection=branch
> >         and -fcheck-pointer-bounds are used together.
> >         (indirect_thunk_prefix): New enum.
> >         (indirect_thunk_need_prefix): New function.
> >         (indirect_thunk_name): Replace need_bnd_p with need_prefix.  Use
> >         "_nt" instead of "_bnd" for NOTRACK prefix.
> >         (output_indirect_thunk): Replace need_bnd_p with need_prefix.
> >         (output_indirect_thunk_function): Likewise.
> >         (): Likewise.
> >         (ix86_code_end): Update output_indirect_thunk_function calls.
> >         (ix86_output_indirect_branch_via_reg): Replace
> >         ix86_bnd_prefixed_insn_p with indirect_thunk_need_prefix.
> >         (ix86_output_indirect_branch_via_push): Likewise.
> >         (ix86_output_function_return): Likewise.
> >         * doc/invoke.texi: Document -mindirect-branch=thunk-extern is
> >         incompatible with -fcf-protection=branch and
> >         -fcheck-pointer-bounds.
> >
> > gcc/testsuite/
> >
> >         PR target/84176
> >         * gcc.target/i386/indirect-thunk-11.c: New test.
> >         * gcc.target/i386/indirect-thunk-12.c: Likewise.
> >         * gcc.target/i386/indirect-thunk-attr-12.c: Likewise.
> >         * gcc.target/i386/indirect-thunk-attr-13.c: Likewise.
> >         * gcc.target/i386/indirect-thunk-attr-14.c: Likewise.
> >         * gcc.target/i386/indirect-thunk-attr-15.c: Likewise.
> >         * gcc.target/i386/indirect-thunk-attr-16.c: Likewise.
> >         * gcc.target/i386/indirect-thunk-extern-10.c: Likewise.
> >         * gcc.target/i386/indirect-thunk-extern-8.c: Likewise.
> >         * gcc.target/i386/indirect-thunk-extern-9.c: Likewise.
> 
> Hi Jan,
> 
> Can you review it:
> 
> https://gcc.gnu.org/ml/gcc-patches/2018-02/msg00113.html

The patch is OK. Sorry for late reaction!

Honza
> 
> Thanks.
> 
> 
> -- 
> H.J.