tracing/probes: Move finding func-proto API and getting func-param API to trace_btf

Move generic function-proto find API and getting function parameter API
to BTF library code from trace_probe.c. This will avoid redundant efforts
on different feature.

Link: https://lore.kernel.org/all/169272155255.160970.719426926348706349.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>

1 files changed, 11 insertions, 40 deletions

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index ecbe28f8d676..c3ac5698e80b 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -12,6 +12,7 @@
 #define pr_fmt(fmt)	"trace_probe: " fmt
 
 #include <linux/bpf.h>
+#include "trace_btf.h"
 
 #include "trace_probe.h"
 
@@ -361,38 +362,6 @@ static const char *type_from_btf_id(struct btf *btf, s32 id)
 	return NULL;
 }
 
-static const struct btf_type *find_btf_func_proto(const char *funcname,
-						  struct btf **btf_p)
-{
-	const struct btf_type *t;
-	struct btf *btf = NULL;
-	s32 id;
-
-	if (!funcname)
-		return ERR_PTR(-EINVAL);
-
-	id = bpf_find_btf_id(funcname, BTF_KIND_FUNC, &btf);
-	if (id <= 0)
-		return ERR_PTR(-ENOENT);
-
-	/* Get BTF_KIND_FUNC type */
-	t = btf_type_by_id(btf, id);
-	if (!t || !btf_type_is_func(t))
-		goto err;
-
-	/* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
-	t = btf_type_by_id(btf, t->type);
-	if (!t || !btf_type_is_func_proto(t))
-		goto err;
-
-	*btf_p = btf;
-	return t;
-
-err:
-	btf_put(btf);
-	return ERR_PTR(-ENOENT);
-}
-
 static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr,
 						   struct btf **btf_p, bool tracepoint)
 {
@@ -403,12 +372,13 @@ static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr
 	if (!funcname || !nr)
 		return ERR_PTR(-EINVAL);
 
-	t = find_btf_func_proto(funcname, &btf);
-	if (IS_ERR(t))
+	t = btf_find_func_proto(funcname, &btf);
+	if (!t)
 		return (const struct btf_param *)t;
 
-	*nr = btf_type_vlen(t);
-	param = (const struct btf_param *)(t + 1);
+	param = btf_get_func_param(t, nr);
+	if (IS_ERR_OR_NULL(param))
+		goto err;
 
 	/* Hide the first 'data' argument of tracepoint */
 	if (tracepoint) {
@@ -421,6 +391,7 @@ static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr
 		return param;
 	}
 
+err:
 	btf_put(btf);
 	return NULL;
 }
@@ -496,8 +467,8 @@ static const struct fetch_type *parse_btf_retval_type(
 
 	if (ctx->funcname) {
 		/* Do not use ctx->btf, because it must be used with ctx->param */
-		t = find_btf_func_proto(ctx->funcname, &btf);
-		if (!IS_ERR(t)) {
+		t = btf_find_func_proto(ctx->funcname, &btf);
+		if (t) {
 			typestr = type_from_btf_id(btf, t->type);
 			btf_put(btf);
 		}
@@ -512,8 +483,8 @@ static bool is_btf_retval_void(const char *funcname)
 	struct btf *btf;
 	bool ret;
 
-	t = find_btf_func_proto(funcname, &btf);
-	if (IS_ERR(t))
+	t = btf_find_func_proto(funcname, &btf);
+	if (!t)
 		return false;
 
 	ret = (t->type == 0);