On Mon, Feb 15, 2021 at 11:42 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote: > [...] > > > > > > > > How does the situation look on other archs when they need to > > > > implement this in future? > > > > Mainly asking whether it would be better to instead to move this > > > > logic into the verifier > > > > instead, so it'll be consistent across all archs. > > > > > > I have exactly the same check in my s390 wip patch. > > > So having a common solution would be great. > > > > We do rewrites for various cases like div/mod handling, perhaps would > > be > > best to emit an explicit BPF_MOV32_REG(insn->dst_reg, insn->dst_reg) > > there, > > see the fixup_bpf_calls(). Agreed, this would be better. > > How about BPF_ZEXT_REG? Then arches that don't need this (I think > aarch64's instruction always zero-extends) can detect this using > insn_is_zext() and skip such insns. > +1
