On 3/16/2021 2:15 PM, Peter Zijlstra wrote:

On Tue, Mar 16, 2021 at 08:10:26AM -0700, Yu-cheng Yu wrote:

quoted

Control-flow Enforcement (CET) is a new Intel processor feature that blocks
return/jump-oriented programming attacks.  Details are in "Intel 64 and
IA-32 Architectures Software Developer's Manual" [1].

CET can protect applications and the kernel.  This series enables only
application-level protection, and has three parts:

   - Shadow stack [2],
   - Indirect branch tracking [3], and
   - Selftests [4].

CET is marketing; afaict SS and IBT are 100% independent and there's no
reason what so ever to have them share any code, let alone a Kconfig
knob.

We used to have shadow stack and ibt under separate Kconfig options, but 
in a few places they actually share same code path, such as the XSAVES 
supervisor states and ELF header for example.  Anyways I will be happy 
to make changes again if there is agreement.

In fact, I think all of this would improve is you remove the CET name
from all of this entirely. Put this series under CONFIG_X86_SHSTK (or
_SS) and use CONFIG_X86_IBT for the other one.

Similarly with the .c file.

All this CET business is just pure confusion.