On Wed, May 13, 2020 at 04:33:49AM +0100, Al Viro wrote: > FWIW, what I'm going to do is > * make all callers of copy_regset_to_user() pass 0 as pos > (there are very few exceptions - one on arm64, three on sparc32 > and five on sparc64; I hadn't dealt with arm64 one yet, but all > cases on sparc are handled)
[snip] Any of that would be easy to backport, though. Several questions regaring XSAVE and friends: * do we ever run on XSAVE/XSAVES-capable hardware with XFEATURE_FP turned off? * is it possible for x86 to have gaps between the state components area as reported by CPUID 0x0d? IOW, can area for feature 2 (XFEATURE_YMM) to start *not* at 0x200 and can area for N start not right after the end of area for N-1 for some N > 2? I think I have an easy-to-backport solution, but I'm really confused about XFEATURE_FP situation...
