Re: [RFC PATCH v3 00/20] KCFI support

[Will Deacon]

On Mon, Jun 13, 2022 at 10:04:12AM -0700, Kees Cook wrote:
> On Fri, Jun 10, 2022 at 04:34:53PM -0700, Sami Tolvanen wrote:
> > KCFI is a proposed forward-edge control-flow integrity scheme for
> > Clang, which is more suitable for kernel use than the existing CFI
> > scheme used by CONFIG_CFI_CLANG. KCFI doesn't require LTO, doesn't
> > alter function references to point to a jump table, and won't break
> > function address equality. The latest LLVM patch is here:
> > 
> >   https://reviews.llvm.org/D119296
> > 
> > This RFC series replaces the current arm64 CFI implementation with
> > KCFI and adds support for x86_64.
> 
> I think the "RFC" prefix for this series can be dropped. :)
> 
> It looks to me like all of Peter's concerns have been addressed. I'd say
> let's get the Clang side landed, and once that's done, land this via x86
> -tip?
> 
> Peter and Will does this sound right to you? It touches arm64, so if
> -tip isn't okay, I could take it in one of my trees?

The arm64 bits look fine to me. Please just check if it conflicts horribly
with -next so that we have a chance to figure out a shared branch if
necessary.

Will