bpf: Add bpf_get_func_ip helper for kprobe programs
Adding bpf_get_func_ip helper for BPF_PROG_TYPE_KPROBE programs,
so it's now possible to call bpf_get_func_ip from both kprobe and
kretprobe programs.
Taking the caller's address from 'struct kprobe::addr', which is
defined for both kprobe and kretprobe.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-5-jolsa@kernel.org
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 3e71503..0b11371 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -961,6 +961,20 @@ static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = {
.arg1_type = ARG_PTR_TO_CTX,
};
+BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs)
+{
+ struct kprobe *kp = kprobe_running();
+
+ return kp ? (u64) kp->addr : 0;
+}
+
+static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = {
+ .func = bpf_get_func_ip_kprobe,
+ .gpl_only = true,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+};
+
const struct bpf_func_proto *
bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
@@ -1092,6 +1106,8 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
case BPF_FUNC_override_return:
return &bpf_override_return_proto;
#endif
+ case BPF_FUNC_get_func_ip:
+ return &bpf_get_func_ip_proto_kprobe;
default:
return bpf_tracing_func_proto(func_id, prog);
}