From: Jiri Olsa <jolsa@redhat.com>
Date: Wed, 14 Jul 2021 11:43:56 +0200
Subject: bpf: Add bpf_get_func_ip helper for kprobe programs
Patch-mainline: v5.15-rc1
Git-commit: 9ffd9f3ff7193933dae171740ab70a103d460065
References: jsc#PED-1377
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
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
include/uapi/linux/bpf.h | 2 +-
kernel/bpf/verifier.c | 2 ++
kernel/trace/bpf_trace.c | 16 ++++++++++++++++
tools/include/uapi/linux/bpf.h | 2 +-
4 files changed, 20 insertions(+), 2 deletions(-)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -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.
*/
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6157,6 +6157,8 @@ static int check_get_func_ip(struct bpf_
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",
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -961,6 +961,20 @@ static const struct bpf_func_proto bpf_g
.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)
{
@@ -1093,6 +1107,8 @@ kprobe_prog_func_proto(enum bpf_func_id
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);
}
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4847,7 +4847,7 @@ 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.
*/