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From: Martin KaFai Lau <kafai@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>,
	<netdev@vger.kernel.org>, Andrii Nakryiko <andrii@kernel.org>
Subject: [PATCH v2 bpf-next 07/14] libbpf: Refactor bpf_object__resolve_ksyms_btf_id
Date: Wed, 24 Mar 2021 18:52:07 -0700	[thread overview]
Message-ID: <20210325015207.1546749-1-kafai@fb.com> (raw)
In-Reply-To: <20210325015124.1543397-1-kafai@fb.com>

This patch refactors most of the logic from
bpf_object__resolve_ksyms_btf_id() into a new function
bpf_object__resolve_ksym_var_btf_id().
It is to get ready for a later patch adding
bpf_object__resolve_ksym_func_btf_id() which resolves
a kernel function to the running kernel btf_id.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 tools/lib/bpf/libbpf.c | 124 ++++++++++++++++++++++-------------------
 1 file changed, 67 insertions(+), 57 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 058b643cbcb1..57123a2179b4 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7394,75 +7394,85 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
 	return err;
 }
 
-static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj)
+static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj,
+					       struct extern_desc *ext)
 {
-	struct extern_desc *ext;
+	const struct btf_type *targ_var, *targ_type;
+	__u32 targ_type_id, local_type_id;
+	const char *targ_var_name;
+	int i, id, btf_fd, err;
 	struct btf *btf;
-	int i, j, id, btf_fd, err;
 
-	for (i = 0; i < obj->nr_extern; i++) {
-		const struct btf_type *targ_var, *targ_type;
-		__u32 targ_type_id, local_type_id;
-		const char *targ_var_name;
-		int ret;
+	btf = obj->btf_vmlinux;
+	btf_fd = 0;
+	id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR);
+	if (id == -ENOENT) {
+		err = load_module_btfs(obj);
+		if (err)
+			return err;
 
-		ext = &obj->externs[i];
-		if (ext->type != EXT_KSYM || !ext->ksym.type_id)
-			continue;
+		for (i = 0; i < obj->btf_module_cnt; i++) {
+			btf = obj->btf_modules[i].btf;
+			/* we assume module BTF FD is always >0 */
+			btf_fd = obj->btf_modules[i].fd;
+			id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR);
+			if (id != -ENOENT)
+				break;
+		}
+	}
+	if (id <= 0) {
+		pr_warn("extern (var ksym) '%s': failed to find BTF ID in kernel BTF(s).\n",
+			ext->name);
+		return -ESRCH;
+	}
 
-		btf = obj->btf_vmlinux;
-		btf_fd = 0;
-		id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR);
-		if (id == -ENOENT) {
-			err = load_module_btfs(obj);
-			if (err)
-				return err;
+	/* find local type_id */
+	local_type_id = ext->ksym.type_id;
 
-			for (j = 0; j < obj->btf_module_cnt; j++) {
-				btf = obj->btf_modules[j].btf;
-				/* we assume module BTF FD is always >0 */
-				btf_fd = obj->btf_modules[j].fd;
-				id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR);
-				if (id != -ENOENT)
-					break;
-			}
-		}
-		if (id <= 0) {
-			pr_warn("extern (ksym) '%s': failed to find BTF ID in kernel BTF(s).\n",
-				ext->name);
-			return -ESRCH;
-		}
+	/* find target type_id */
+	targ_var = btf__type_by_id(btf, id);
+	targ_var_name = btf__name_by_offset(btf, targ_var->name_off);
+	targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id);
 
-		/* find local type_id */
-		local_type_id = ext->ksym.type_id;
+	err = bpf_core_types_are_compat(obj->btf, local_type_id,
+					btf, targ_type_id);
+	if (err <= 0) {
+		const struct btf_type *local_type;
+		const char *targ_name, *local_name;
 
-		/* find target type_id */
-		targ_var = btf__type_by_id(btf, id);
-		targ_var_name = btf__name_by_offset(btf, targ_var->name_off);
-		targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id);
+		local_type = btf__type_by_id(obj->btf, local_type_id);
+		local_name = btf__name_by_offset(obj->btf, local_type->name_off);
+		targ_name = btf__name_by_offset(btf, targ_type->name_off);
 
-		ret = bpf_core_types_are_compat(obj->btf, local_type_id,
-						btf, targ_type_id);
-		if (ret <= 0) {
-			const struct btf_type *local_type;
-			const char *targ_name, *local_name;
+		pr_warn("extern (var ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n",
+			ext->name, local_type_id,
+			btf_kind_str(local_type), local_name, targ_type_id,
+			btf_kind_str(targ_type), targ_name);
+		return -EINVAL;
+	}
 
-			local_type = btf__type_by_id(obj->btf, local_type_id);
-			local_name = btf__name_by_offset(obj->btf, local_type->name_off);
-			targ_name = btf__name_by_offset(btf, targ_type->name_off);
+	ext->is_set = true;
+	ext->ksym.kernel_btf_obj_fd = btf_fd;
+	ext->ksym.kernel_btf_id = id;
+	pr_debug("extern (var ksym) '%s': resolved to [%d] %s %s\n",
+		 ext->name, id, btf_kind_str(targ_var), targ_var_name);
 
-			pr_warn("extern (ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n",
-				ext->name, local_type_id,
-				btf_kind_str(local_type), local_name, targ_type_id,
-				btf_kind_str(targ_type), targ_name);
-			return -EINVAL;
-		}
+	return 0;
+}
+
+static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj)
+{
+	struct extern_desc *ext;
+	int i, err;
+
+	for (i = 0; i < obj->nr_extern; i++) {
+		ext = &obj->externs[i];
+		if (ext->type != EXT_KSYM || !ext->ksym.type_id)
+			continue;
 
-		ext->is_set = true;
-		ext->ksym.kernel_btf_obj_fd = btf_fd;
-		ext->ksym.kernel_btf_id = id;
-		pr_debug("extern (ksym) '%s': resolved to [%d] %s %s\n",
-			 ext->name, id, btf_kind_str(targ_var), targ_var_name);
+		err = bpf_object__resolve_ksym_var_btf_id(obj, ext);
+		if (err)
+			return err;
 	}
 	return 0;
 }
-- 
2.30.2


  parent reply	other threads:[~2021-03-25  1:52 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-25  1:51 [PATCH v2 bpf-next 00/14] bpf: Support calling kernel function Martin KaFai Lau
2021-03-25  1:51 ` [PATCH v2 bpf-next 01/14] bpf: Simplify freeing logic in linfo and jited_linfo Martin KaFai Lau
2021-03-25  1:51 ` [PATCH v2 bpf-next 02/14] bpf: Refactor btf_check_func_arg_match Martin KaFai Lau
2021-03-25  1:51 ` [PATCH v2 bpf-next 03/14] bpf: Support bpf program calling kernel function Martin KaFai Lau
2021-03-25 22:02   ` Toke Høiland-Jørgensen
2021-03-25 23:09     ` Martin KaFai Lau
2021-03-26 10:11       ` Toke Høiland-Jørgensen
2021-03-26 14:20         ` Alexei Starovoitov
2021-03-26 15:14           ` Toke Høiland-Jørgensen
2021-03-27  3:59   ` Alexei Starovoitov
2021-03-25  1:51 ` [PATCH v2 bpf-next 04/14] bpf: Support kernel function call in x86-32 Martin KaFai Lau
2021-03-25  1:51 ` [PATCH v2 bpf-next 05/14] tcp: Rename bictcp function prefix to cubictcp Martin KaFai Lau
2021-03-25  1:52 ` [PATCH v2 bpf-next 06/14] bpf: tcp: Put some tcp cong functions in allowlist for bpf-tcp-cc Martin KaFai Lau
2021-03-25  1:52 ` Martin KaFai Lau [this message]
2021-03-25  1:52 ` [PATCH v2 bpf-next 08/14] libbpf: Refactor codes for finding btf id of a kernel symbol Martin KaFai Lau
2021-03-25  1:52 ` [PATCH v2 bpf-next 09/14] libbpf: Rename RELO_EXTERN to RELO_EXTERN_VAR Martin KaFai Lau
2021-03-25  1:52 ` [PATCH v2 bpf-next 10/14] libbpf: Record extern sym relocation first Martin KaFai Lau
2021-03-25  1:52 ` [PATCH v2 bpf-next 11/14] libbpf: Support extern kernel function Martin KaFai Lau
2021-03-25  1:52 ` [PATCH v2 bpf-next 12/14] bpf: selftests: Rename bictcp to bpf_cubic Martin KaFai Lau
2021-03-25  1:52 ` [PATCH v2 bpf-next 13/14] bpf: selftests: bpf_cubic and bpf_dctcp calling kernel functions Martin KaFai Lau
2021-03-25  1:52 ` [PATCH v2 bpf-next 14/14] bpf: selftests: Add kfunc_call test Martin KaFai Lau
2021-03-27  3:50 ` [PATCH v2 bpf-next 00/14] bpf: Support calling kernel function patchwork-bot+netdevbpf
2021-03-27 21:25 ` Cong Wang
2021-03-27 21:28   ` Alexei Starovoitov
2021-03-27 22:07     ` Cong Wang
2021-03-27 22:53       ` Alexei Starovoitov
2021-03-28 20:13         ` Cong Wang
2021-03-29  1:24           ` Martin KaFai Lau
2021-03-29 16:06             ` Lorenz Bauer
2021-03-29 19:08               ` Martin KaFai Lau
2021-03-31  6:44                 ` Andrii Nakryiko
2021-04-01 19:51                   ` Martin KaFai Lau
2021-04-01 19:52                     ` Andrii Nakryiko
2021-03-29 20:18             ` Cong Wang
2021-03-30  9:43 ` Lorenz Bauer
2021-03-30 14:35   ` Alexei Starovoitov
2021-03-30 19:58     ` Cong Wang
2021-03-30 21:43       ` Martin KaFai Lau
2021-03-31  3:28         ` [External] " Jiang Wang .
2021-03-31  4:55           ` Martin KaFai Lau

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