Re: [PATCH 03/10] bpf: Add bpf_get_func_ip kprobe helper for multi kprobe link

Andrii Nakryiko
2022-03-04T23:11:24Z

On Tue, Feb 22, 2022 at 9:06 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding support to call bpf_get_func_ip helper from kprobe
> programs attached by multi kprobe link.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---

LGTM.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

> kernel/trace/bpf_trace.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index df3771bfd6e5..64891b7b0885 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1037,6 +1037,18 @@ static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = {
> .arg1_type = ARG_PTR_TO_CTX,
> };
>
> +BPF_CALL_1(bpf_get_func_ip_kprobe_multi, struct pt_regs *, regs)
> +{
> + return instruction_pointer(regs);
> +}
> +
> +static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe_multi = {
> + .func = bpf_get_func_ip_kprobe_multi,
> + .gpl_only = false,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_PTR_TO_CTX,
> +};
> +
> BPF_CALL_1(bpf_get_attach_cookie_trace, void *, ctx)
> {
> struct bpf_trace_run_ctx *run_ctx;
> @@ -1280,7 +1292,9 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> return &bpf_override_return_proto;
> #endif
> case BPF_FUNC_get_func_ip:
> - return &bpf_get_func_ip_proto_kprobe;
> + return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI ?
> + &bpf_get_func_ip_proto_kprobe_multi :
> + &bpf_get_func_ip_proto_kprobe;
> case BPF_FUNC_get_attach_cookie:
> return &bpf_get_attach_cookie_proto_trace;
> default:
> --
> 2.35.1
>