Re: [PATCH 35/35] x86/cpufeatures: Limit shadow stack to Intel CPUs

John Allen
2022-02-04T22:21:26Z

On Thu, Feb 03, 2022 at 02:23:43PM -0800, H.J. Lu wrote:
> On Thu, Feb 3, 2022 at 1:58 PM John Allen <john.allen@amd.com> wrote:
> >
> > On Sun, Jan 30, 2022 at 01:18:38PM -0800, Rick Edgecombe wrote:
> > > Shadow stack is supported on newer AMD processors, but the kernel
> > > implementation has not been tested on them. Prevent basic issues from
> > > showing up for normal users by disabling shadow stack on all CPUs except
> > > Intel until it has been tested. At which point the limitation should be
> > > removed.
> >
> > Hi Rick,
> >
> > I have been testing Yu-Cheng's patchsets on AMD hardware and I am
> > working on testing this version now. How are you testing this new
> > series? I can partially test by calling the prctl enable for shadow
> > stack directly from a program, but I'm not sure how useful that's going
> > to be without the glibc support. Do you have a public repo with the
> > necessary glibc changes to enable shadow stack early?
> >
>
> The glibc CET branch is at
>
> https://gitlab.com/x86-glibc/glibc/-/commits/users/hjl/cet/master

Thanks, I ran some smoke tests with the updated glibc and it's looking
good so far. Additionally, I ran the new kselftest and it passed.

Thanks,
John

>
> --
> H.J.