Re: [PATCH v10 01/26] Documentation/x86: Add CET description

[Dave Hansen]

On 4/29/20 3:07 PM, Yu-cheng Yu wrote:
> +Note:
> +  There is no CET-enabling arch_prctl function.  By design, CET is enabled
> +  automatically if the binary and the system can support it.

I think Andy and I danced around this last time.  Let me try to say it
more explicitly.

I want CET kernel enabling to able to be disconnected from the on-disk
binary.  I want a binary compiled with CET to be able to disable it, and
I want a binary not compiled with CET to be able to enable it.  I want
different threads in a process to be able to each have different CET status.

Which JITs was this tested with?  I think as a bare minimum we need to
know that this design can accommodate _a_ modern JIT.  It would be
horrible if the browser javascript engines couldn't use this design, for
instance.