svn commit: r361302 - in head: share/man/man7 sys/amd64/amd64 sys/i386/i386 sys/x86/include sys/x86/x86

[Konstantin Belousov]

On Wed, May 20, 2020 at 10:00:31PM +0000, Konstantin Belousov wrote:
> Author: kib
> Date: Wed May 20 22:00:31 2020
> New Revision: 361302
> URL: https://svnweb.freebsd.org/changeset/base/361302
> 
> Log:
>   amd64: Add a knob to flush RSB on context switches if machine has SMEP.
>   
>   The flush is needed to prevent cross-process ret2spec, which is not handled
>   on kernel entry if IBPB is enabled but SMEP is present.
>   While there, add i386 RSB flush.
>   
>   Reported by:	Anthony Steinhauser <asteinhauser at google.com>
>   Reviewed by:	markj, Anthony Steinhauser
>   Discussed with:	philip
>   admbugs:	961
>   Sponsored by:	The FreeBSD Foundation
>   MFC after:	1 week
https://reviews.freebsd.org/D24868