Re: [PATCH 07/10] libbpf: Add bpf_link_create support for multi kprobes

Andrii Nakryiko
2022-03-04T23:11:43Z

On Tue, Feb 22, 2022 at 9:07 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding new kprobe_multi struct to bpf_link_create_opts object
> to pass multiple kprobe data to link_create attr uapi.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/lib/bpf/bpf.c | 7 +++++++
> tools/lib/bpf/bpf.h | 9 ++++++++-
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 418b259166f8..5e180def2cef 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -853,6 +853,13 @@ int bpf_link_create(int prog_fd, int target_fd,
> if (!OPTS_ZEROED(opts, perf_event))
> return libbpf_err(-EINVAL);
> break;
> + case BPF_TRACE_KPROBE_MULTI:
> + attr.link_create.kprobe_multi.syms = OPTS_GET(opts, kprobe_multi.syms, 0);
> + attr.link_create.kprobe_multi.addrs = OPTS_GET(opts, kprobe_multi.addrs, 0);
> + attr.link_create.kprobe_multi.cookies = OPTS_GET(opts, kprobe_multi.cookies, 0);
> + attr.link_create.kprobe_multi.cnt = OPTS_GET(opts, kprobe_multi.cnt, 0);
> + attr.link_create.kprobe_multi.flags = OPTS_GET(opts, kprobe_multi.flags, 0);
> + break;
> default:
> if (!OPTS_ZEROED(opts, flags))
> return libbpf_err(-EINVAL);
> diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
> index 16b21757b8bf..bd285a8f3420 100644
> --- a/tools/lib/bpf/bpf.h
> +++ b/tools/lib/bpf/bpf.h
> @@ -413,10 +413,17 @@ struct bpf_link_create_opts {
> struct {
> __u64 bpf_cookie;
> } perf_event;
> + struct {
> + __u64 syms;
> + __u64 addrs;
> + __u64 cookies;

hm, I think we can and should use proper types here, no?

const char **syms;
const void **addrs;
const __u64 *cookies;

?

> + __u32 cnt;
> + __u32 flags;
> + } kprobe_multi;
> };
> size_t :0;
> };
> -#define bpf_link_create_opts__last_field perf_event
> +#define bpf_link_create_opts__last_field kprobe_multi.flags
>
> LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,
> enum bpf_attach_type attach_type,
> --
> 2.35.1
>