Kees Cook and others have been porting or reimplementing features exclusive to grsec in upstream linux.

https://outflux.net/blog/archives/2016/09/26/security-things...

https://outflux.net/blog/archives/2016/09/27/security-things...

https://outflux.net/blog/archives/2016/09/28/security-things...

https://outflux.net/blog/archives/2016/09/30/security-things...

https://outflux.net/blog/archives/2016/10/03/security-things...

https://outflux.net/blog/archives/2016/10/04/security-things...

And naturally some stuff is exclusive to linux upstream, though grsec will benefit from those automatically if they deem it good enough.