On Thu, May 12 2022 at 17:46, Dave Hansen wrote: > On 5/12/22 17:08, H.J. Lu wrote: > If I had to take a shot at this today, I think I'd opt for: > > mask = sys_enable_masking(bits=6, flags=FUZZY_NR_BITS); > > although I'm not super confident about the "fuzzy" flag. I also don't > think I'd totally hate the "blind" interface where the kernel just gets > to pick unilaterally and takes zero input from userspace. That's the only sane choice and you can make it simple for userspace: ret = prctl(GET_XXX_MASK, &mask); and then let it decide based on @ret and @mask whether to use it or not. But of course nobody thought about this as a generic feature and so we have the ARM64 TBI muck as a precedence. So much for coordination and portability... I'm so tired of this short sighted 'cram my feature in' approach of _all_ involved parties. Thanks, tglx