[RFC PATCH 2/5] bpf: Pass trace_probe to bpf_prog for variable fetching

[He Kuang <hekuang@huawei.com>]

Add new structure bpf_pt_regs, which contains both original
'ctx'(pt_regs) and trabe_probe pointer, and pass this new pointer to bpf
prog for variable fetching.

Signed-off-by: He Kuang <hekuang@huawei.com>
---
 kernel/trace/trace_kprobe.c | 11 +++++++++--
 kernel/trace/trace_probe.h  |  5 +++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index d0ce590..cee0b28 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1141,8 +1141,15 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
 	int size, __size, dsize;
 	int rctx;
 
-	if (prog && !trace_call_bpf(prog, regs))
-		return;
+	if (prog) {
+		struct bpf_pt_regs bpf_pt_regs;
+
+		bpf_pt_regs.pt_regs = *regs;
+		bpf_pt_regs.tp = &tk->tp;
+
+		if (!trace_call_bpf(prog, &bpf_pt_regs))
+			return;
+	}
 
 	head = this_cpu_ptr(call->perf_events);
 	if (hlist_empty(head))
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index ab283e1..5b1f12c 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -391,4 +391,9 @@ store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
 	}
 }
 
+struct bpf_pt_regs {
+	struct pt_regs pt_regs;
+	struct trace_probe *tp;
+};
+
 extern int set_print_fmt(struct trace_probe *tp, bool is_return);
-- 
1.8.5.2