On Thu, May 12, 2022 at 08:05:26PM -0700, Dave Hansen wrote: > On 5/12/22 18:27, Thomas Gleixner wrote: > > 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. > > Well, not quite *nobody*: > > https://lore.kernel.org/linux-arm-kernel/7a34470c-73f0-26ac-e63d-161191d4b1e4@xxxxxxxxx/ In the first RFC I tried to get ARM TBI interface generic. I resurrect it if it fits better: https://lore.kernel.org/all/20210205151631.43511-2-kirill.shutemov@xxxxxxxxxxxxxxx/ -- Kirill A. Shutemov
