On Wed, Jan 25, 2023 at 10:38:17PM +0100, Ilya Leoshkevich wrote:
> +
> + /* Sign-extend the kfunc arguments. */
> + if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
> + m = bpf_jit_find_kfunc_model(fp, insn);
> + if (!m)
> + return -1;
> +
> + for (j = 0; j < m->nr_args; j++) {
> + if (sign_extend(jit, BPF_REG_1 + j,
> + m->arg_size[j],
> + m->arg_flags[j]))
> + return -1;
> + }
> + }
Is this because s390 doesn't have subregisters?
Could you give an example where it's necessary?
I'm guessing a bpf prog compiled with alu32 and operates on signed int
that is passed into a kfunc that expects 'int' in 64-bit reg?
>
> +bool bpf_jit_supports_kfunc_call(void)
> +{
> + return true;
> +}
Timely :) Thanks for working it.
