> > -static int bpf_core_apply_relo(struct bpf_program *prog,
> > - const struct bpf_core_relo *relo,
> > - int relo_idx,
> > - const struct btf *local_btf,
> > - struct hashmap *cand_cache)
> > +static int bpf_core_calc_relo_res(struct bpf_program *prog,
>
> bpf_core_calc_relo_res is almost indistinguishable from
> bpf_core_calc_relo... Let's call this one bpf_core_resolve_relo()?
>
That's a much better name! Deciding the name of that function was
probably the most complicated part of this patch.
> > @@ -5636,12 +5627,31 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
> > if (!prog->load)
> > continue;
> >
> > - err = bpf_core_apply_relo(prog, rec, i, obj->btf, cand_cache);
> > + err = bpf_core_calc_relo_res(prog, rec, i, obj->btf, cand_cache, &targ_res);
> > if (err) {
> > pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
> > prog->name, i, err);
> > goto out;
> > }
> > +
> > + if (rec->insn_off % BPF_INSN_SZ)
> > + return -EINVAL;
> > + insn_idx = rec->insn_off / BPF_INSN_SZ;
> > + /* adjust insn_idx from section frame of reference to the local
> > + * program's frame of reference; (sub-)program code is not yet
> > + * relocated, so it's enough to just subtract in-section offset
> > + */
> > + insn_idx = insn_idx - prog->sec_insn_off;
> > + if (insn_idx >= prog->insns_cnt)
> > + return -EINVAL;
> > + insn = &prog->insns[insn_idx];
>
> this is sort of like sanity checks, let's do them before the core_calc
> step, so after that it's a clean sequence of calc_relo + pathc_insn?
>
Makes sense.
> > @@ -1177,18 +1152,18 @@ static void bpf_core_dump_spec(const char *prog_name, int level, const struct bp
> > * between multiple relocations for the same type ID and is updated as some
> > * of the candidates are pruned due to structural incompatibility.
> > */
> > -int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
> > - int insn_idx,
> > - const struct bpf_core_relo *relo,
> > - int relo_idx,
> > - const struct btf *local_btf,
> > - struct bpf_core_cand_list *cands,
> > - struct bpf_core_spec *specs_scratch)
> > +int bpf_core_calc_relo_insn(const char *prog_name,
>
> please update the comment for this function, it's not "CO-RE relocate
> single instruction" anymore, it's more like "Calculate CO-RE
> relocation target result" or something along those lines.
>
Updated with your suggestion.
> > @@ -1223,12 +1198,12 @@ int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
> > /* TYPE_ID_LOCAL relo is special and doesn't need candidate search */
> > if (relo->kind == BPF_CORE_TYPE_ID_LOCAL) {
> > /* bpf_insn's imm value could get out of sync during linking */
> > - memset(&targ_res, 0, sizeof(targ_res));
> > - targ_res.validate = false;
> > - targ_res.poison = false;
> > - targ_res.orig_val = local_spec->root_type_id;
> > - targ_res.new_val = local_spec->root_type_id;
> > - goto patch_insn;
> > + memset(targ_res, 0, sizeof(*targ_res));
> > + targ_res->validate = true;
>
> hm.. original code sets it to false here, please don't regress the logic
>
ops, I introduced this by mistake while rebasing.
