Commit 9ffd9f3f authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

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: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Reviewed-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-5-jolsa@kernel.org
parent 9b99edca

include/uapi/linux/bpf.h

+1 −1
Original line number Diff line number Diff line
@@ -4844,7 +4844,7 @@ union bpf_attr { 
 *

 * u64 bpf_get_func_ip(void *ctx)

 * 	Description

 * 		Get address of the traced function (for tracing programs).

 * 		Get address of the traced function (for tracing and kprobe programs).

 * 	Return

 * 		Address of the traced function.

 */

kernel/bpf/verifier.c

+2 −0
Original line number Diff line number Diff line
@@ -6175,6 +6175,8 @@ static int check_get_func_ip(struct bpf_verifier_env *env) 
			return -ENOTSUPP;

		}

		return 0;

	} else if (type == BPF_PROG_TYPE_KPROBE) {

		return 0;

	}



	verbose(env, "func %s#%d not supported for program type %d\n",

kernel/trace/bpf_trace.c

+16 −0
Original line number Diff line number Diff line
@@ -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);

	}

tools/include/uapi/linux/bpf.h

+1 −1
Original line number Diff line number Diff line
@@ -4844,7 +4844,7 @@ union bpf_attr { 
 *

 * u64 bpf_get_func_ip(void *ctx)

 * 	Description

 * 		Get address of the traced function (for tracing programs).

 * 		Get address of the traced function (for tracing and kprobe programs).

 * 	Return

 * 		Address of the traced function.

 */