Re: [PATCH v15 01/26] Documentation/x86: Add CET description

[Yu, Yu-cheng]

On 11/30/2020 11:38 AM, Fāng-ruì Sòng wrote:
> On Mon, Nov 30, 2020 at 10:34 AM Yu, Yu-cheng <yu-cheng.yu@xxxxxxxxx> wrote:
> > On 11/30/2020 10:26 AM, Nick Desaulniers wrote:
> > > (In response to https://lore.kernel.org/lkml/20201110162211.9207-2-yu-cheng.yu@xxxxxxxxx/)
> > >
> > > > These need to be enabled to build a CET-enabled kernel, and Binutils v2.31
> > > > and GCC v8.1 or later are required to build a CET kernel.
> > >
> > > What about LLVM? Surely CrOS might be of interest to ship this on (we ship the
> > > equivalent for aarch64 on Android).
> >
> > I have not built with LLVM, but think it probably will work as well.  I
> > will test it.
> >
> > > > An application's CET capability is marked in its ELF header and can be
> > > > verified from the following command output, in the NT_GNU_PROPERTY_TYPE_0
> > > > field:
> > > >
> > > >       readelf -n <application> | grep SHSTK
> > > >           properties: x86 feature: IBT, SHSTK
> > >
> > > Same for llvm-readelf.
> >
> > I will add that to the document.
> >
> > Thanks,
> > Yu-cheng
>
> The baseline LLVM version is 10.0.1, which is good enough for  clang
> -fcf-protection=full, llvm-readelf -n, LLD's .note.gnu.property
> handling (the LLD option is `-z force-ibt`, though)

Thanks!

Yu-cheng