[PATCH] x86: Support IBT and SHSTK in Intel CET [BZ #21598]

[H.J. Lu]

On Tue, Dec 19, 2017 at 8:47 AM, Joseph Myers <joseph@codesourcery.com> wrote:
> On Tue, 19 Dec 2017, H.J. Lu wrote:
>
>>   b. Otherwise lock SHSTK.
>> 3. After SHSTK is enabled, it is an error to load a shared object
>> without GNU_PROPERTY_X86_FEATURE_1_SHSTK.
>
> This seems like something that would be unsafe to enable by default in
> glibc / the toolchain as a whole, because it would mean that rebuilding a
> program (and the shared libraries it uses at startup) stops it from
> dlopening existing shared objects.  That is, making it an error to load
> existing shared objects should only be enabled by an explicit non-default
> option (whether configure-time option for glibc, or link-time option for
> programs that do not use dlopen) that is only used when building for a
> system where it is known that there is no need to be able to dlopen any
> existing shared object.

I will change it to default to no.

-- 
H.J.