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Message-ID: <20210316011426.4178537-1-kafai@fb.com>
Date: Mon, 15 Mar 2021 18:14:26 -0700
From: Martin KaFai Lau <kafai@...com>
To: <bpf@...r.kernel.org>
CC: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>, <kernel-team@...com>,
<netdev@...r.kernel.org>
Subject: [PATCH bpf-next 08/15] libbpf: Refactor bpf_object__resolve_ksyms_btf_id
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.
Signed-off-by: Martin KaFai Lau <kafai@...com>
---
tools/lib/bpf/libbpf.c | 125 ++++++++++++++++++++++-------------------
1 file changed, 68 insertions(+), 57 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2f351d3ad3e7..7d5f9b7877bc 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7403,75 +7403,86 @@ 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;
+
+ err = bpf_object__resolve_ksym_var_btf_id(obj, ext);
- 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);
+ if (err)
+ return err;
}
return 0;
}
--
2.30.2
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