From: Kui-Feng Lee <thinker.li@xxxxxxxxx>
Find module BTFs for struct_ops maps and progs and pass them to the kernel.
It ensures the kernel resolve type IDs from correct module BTFs.
For the map of a struct_ops object, mod_btf is added to bpf_map to keep a
reference to the module BTF. It's FD is passed to the kernel as mod_btf_fd
when it is created.
For a prog attaching to a struct_ops object, attach_btf_obj_fd of bpf_prog
is the FD pointing to a module BTF in the kernel.
Signed-off-by: Kui-Feng Lee <thinker.li@xxxxxxxxx>
---
tools/lib/bpf/bpf.c | 3 +-
tools/lib/bpf/bpf.h | 4 +-
tools/lib/bpf/libbpf.c | 121 ++++++++++++++++++++++++-----------------
3 files changed, 75 insertions(+), 53 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index b0f1913763a3..df4b7570ad92 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -169,7 +169,7 @@ int bpf_map_create(enum bpf_map_type map_type,
__u32 max_entries,
const struct bpf_map_create_opts *opts)
{
- const size_t attr_sz = offsetofend(union bpf_attr, map_extra);
+ const size_t attr_sz = offsetofend(union bpf_attr, mod_btf_fd);
union bpf_attr attr;
int fd;
@@ -191,6 +191,7 @@ int bpf_map_create(enum bpf_map_type map_type,
attr.btf_key_type_id = OPTS_GET(opts, btf_key_type_id, 0);
attr.btf_value_type_id = OPTS_GET(opts, btf_value_type_id, 0);
attr.btf_vmlinux_value_type_id = OPTS_GET(opts, btf_vmlinux_value_type_id, 0);
+ attr.mod_btf_fd = OPTS_GET(opts, mod_btf_fd, 0);
attr.inner_map_fd = OPTS_GET(opts, inner_map_fd, 0);
attr.map_flags = OPTS_GET(opts, map_flags, 0);
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 74c2887cfd24..d18f75b0ccc9 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -51,8 +51,10 @@ struct bpf_map_create_opts {
__u32 numa_node;
__u32 map_ifindex;
+
+ __u32 mod_btf_fd;
};
-#define bpf_map_create_opts__last_field map_ifindex
+#define bpf_map_create_opts__last_field mod_btf_fd
LIBBPF_API int bpf_map_create(enum bpf_map_type map_type,
const char *map_name,
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3a6108e3238b..df6ba5494adb 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -519,6 +519,7 @@ struct bpf_map {
struct bpf_map_def def;
__u32 numa_node;
__u32 btf_var_idx;
+ struct module_btf *mod_btf;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
__u32 btf_vmlinux_value_type_id;
@@ -893,6 +894,42 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
return 0;
}
+static int load_module_btfs(struct bpf_object *obj);
+
+static int find_kern_btf_id(struct bpf_object *obj, const char *kern_name,
+ __u16 kind, struct btf **res_btf,
+ struct module_btf **res_mod_btf)
+{
+ struct module_btf *mod_btf;
+ struct btf *btf;
+ int i, id, err;
+
+ btf = obj->btf_vmlinux;
+ mod_btf = NULL;
+ id = btf__find_by_name_kind(btf, kern_name, kind);
+
+ if (id == -ENOENT) {
+ err = load_module_btfs(obj);
+ if (err)
+ return err;
+
+ for (i = 0; i < obj->btf_module_cnt; i++) {
+ /* we assume module_btf's BTF FD is always >0 */
+ mod_btf = &obj->btf_modules[i];
+ btf = mod_btf->btf;
+ id = btf__find_by_name_kind_own(btf, kern_name, kind);
+ if (id != -ENOENT)
+ break;
+ }
+ }
+ if (id <= 0)
+ return -ESRCH;
+
+ *res_btf = btf;
+ *res_mod_btf = mod_btf;
+ return id;
+}
+
static const struct btf_member *
find_member_by_offset(const struct btf_type *t, __u32 bit_offset)
{
@@ -927,17 +964,23 @@ static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
const char *name, __u32 kind);
static int
-find_struct_ops_kern_types(const struct btf *btf, const char *tname,
+find_struct_ops_kern_types(struct bpf_object *obj, const char *tname,
+ struct module_btf **mod_btf,
const struct btf_type **type, __u32 *type_id,
const struct btf_type **vtype, __u32 *vtype_id,
const struct btf_member **data_member)
{
const struct btf_type *kern_type, *kern_vtype;
const struct btf_member *kern_data_member;
+ struct btf *btf;
__s32 kern_vtype_id, kern_type_id;
__u32 i;
- kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT);
+ /* XXX: should search module BTFs as well. We need module name here
+ * to locate a correct BTF type.
+ */
+ kern_type_id = find_kern_btf_id(obj, tname, BTF_KIND_STRUCT,
+ &btf, mod_btf);
if (kern_type_id < 0) {
pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n",
tname);
@@ -992,13 +1035,15 @@ static bool bpf_map__is_struct_ops(const struct bpf_map *map)
/* Init the map's fields that depend on kern_btf */
static int bpf_map__init_kern_struct_ops(struct bpf_map *map,
- const struct btf *btf,
- const struct btf *kern_btf)
+ struct bpf_object *obj)
{
const struct btf_member *member, *kern_member, *kern_data_member;
const struct btf_type *type, *kern_type, *kern_vtype;
__u32 i, kern_type_id, kern_vtype_id, kern_data_off;
struct bpf_struct_ops *st_ops;
+ const struct btf *kern_btf;
+ struct module_btf *mod_btf;
+ const struct btf *btf = obj->btf;
void *data, *kern_data;
const char *tname;
int err;
@@ -1006,16 +1051,19 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map,
st_ops = map->st_ops;
type = st_ops->type;
tname = st_ops->tname;
- err = find_struct_ops_kern_types(kern_btf, tname,
+ err = find_struct_ops_kern_types(obj, tname, &mod_btf,
&kern_type, &kern_type_id,
&kern_vtype, &kern_vtype_id,
&kern_data_member);
if (err)
return err;
+ kern_btf = mod_btf ? mod_btf->btf : obj->btf_vmlinux;
+
pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n",
map->name, st_ops->type_id, kern_type_id, kern_vtype_id);
+ map->mod_btf = mod_btf;
map->def.value_size = kern_vtype->size;
map->btf_vmlinux_value_type_id = kern_vtype_id;
@@ -1091,6 +1139,9 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map,
return -ENOTSUP;
}
+ /* XXX: attach_btf_obj_fd is needed as well */
+ if (mod_btf)
+ prog->attach_btf_obj_fd = mod_btf->fd;
prog->attach_btf_id = kern_type_id;
prog->expected_attach_type = kern_member_idx;
@@ -1133,8 +1184,8 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj)
if (!bpf_map__is_struct_ops(map))
continue;
- err = bpf_map__init_kern_struct_ops(map, obj->btf,
- obj->btf_vmlinux);
+ /* XXX: should be a module btf if not vmlinux */
+ err = bpf_map__init_kern_struct_ops(map, obj);
if (err)
return err;
}
@@ -5193,8 +5244,10 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
create_attr.numa_node = map->numa_node;
create_attr.map_extra = map->map_extra;
- if (bpf_map__is_struct_ops(map))
+ if (bpf_map__is_struct_ops(map)) {
create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id;
+ create_attr.mod_btf_fd = map->mod_btf ? map->mod_btf->fd : 0;
+ }
if (obj->btf && btf__fd(obj->btf) >= 0) {
create_attr.btf_fd = btf__fd(obj->btf);
@@ -7700,40 +7753,6 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
return libbpf_kallsyms_parse(kallsyms_cb, obj);
}
-static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name,
- __u16 kind, struct btf **res_btf,
- struct module_btf **res_mod_btf)
-{
- struct module_btf *mod_btf;
- struct btf *btf;
- int i, id, err;
-
- btf = obj->btf_vmlinux;
- mod_btf = NULL;
- id = btf__find_by_name_kind(btf, ksym_name, kind);
-
- if (id == -ENOENT) {
- err = load_module_btfs(obj);
- if (err)
- return err;
-
- for (i = 0; i < obj->btf_module_cnt; i++) {
- /* we assume module_btf's BTF FD is always >0 */
- mod_btf = &obj->btf_modules[i];
- btf = mod_btf->btf;
- id = btf__find_by_name_kind_own(btf, ksym_name, kind);
- if (id != -ENOENT)
- break;
- }
- }
- if (id <= 0)
- return -ESRCH;
-
- *res_btf = btf;
- *res_mod_btf = mod_btf;
- return id;
-}
-
static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj,
struct extern_desc *ext)
{
@@ -7744,7 +7763,7 @@ static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj,
struct btf *btf = NULL;
int id, err;
- id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf);
+ id = find_kern_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf);
if (id < 0) {
if (id == -ESRCH && ext->is_weak)
return 0;
@@ -7798,7 +7817,7 @@ static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj,
local_func_proto_id = ext->ksym.type_id;
- kfunc_id = find_ksym_btf_id(obj, ext->essent_name ?: ext->name, BTF_KIND_FUNC, &kern_btf,
+ kfunc_id = find_kern_btf_id(obj, ext->essent_name ?: ext->name, BTF_KIND_FUNC, &kern_btf,
&mod_btf);
if (kfunc_id < 0) {
if (kfunc_id == -ESRCH && ext->is_weak)
@@ -9464,9 +9483,9 @@ static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
return err;
}
-static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name,
- enum bpf_attach_type attach_type,
- int *btf_obj_fd, int *btf_type_id)
+static int find_kernel_attach_btf_id(struct bpf_object *obj, const char *attach_name,
+ enum bpf_attach_type attach_type,
+ int *btf_obj_fd, int *btf_type_id)
{
int ret, i;
@@ -9531,7 +9550,7 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attac
*btf_obj_fd = 0;
*btf_type_id = 1;
} else {
- err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id);
+ err = find_kernel_attach_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id);
}
if (err) {
pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %d\n",
@@ -12945,9 +12964,9 @@ int bpf_program__set_attach_target(struct bpf_program *prog,
err = bpf_object__load_vmlinux_btf(prog->obj, true);
if (err)
return libbpf_err(err);
- err = find_kernel_btf_id(prog->obj, attach_func_name,
- prog->expected_attach_type,
- &btf_obj_fd, &btf_id);
+ err = find_kernel_attach_btf_id(prog->obj, attach_func_name,
+ prog->expected_attach_type,
+ &btf_obj_fd, &btf_id);
if (err)
return libbpf_err(err);
}
--
2.34.1
