bpf: Add bpf_get_func_ip kprobe helper for multi kprobe link

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>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-5-jolsa@kernel.org

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index fffa217..2507509 100644 (file)
--- 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: