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Message-Id: <20210417033224.8063-11-alexei.starovoitov@gmail.com>
Date: Fri, 16 Apr 2021 20:32:19 -0700
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: davem@...emloft.net
Cc: daniel@...earbox.net, andrii@...nel.org, netdev@...r.kernel.org,
bpf@...r.kernel.org, kernel-team@...com
Subject: [PATCH bpf-next 10/15] bpf: Add bpf_btf_find_by_name_kind() helper.
From: Alexei Starovoitov <ast@...nel.org>
Add bpf_btf_find_by_name_kind() helper.
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
---
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 8 ++++++
kernel/bpf/btf.c | 51 ++++++++++++++++++++++++++++++++++
kernel/bpf/syscall.c | 2 ++
tools/include/uapi/linux/bpf.h | 8 ++++++
5 files changed, 70 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1aede7ceea5e..fe28ccb57f83 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1970,6 +1970,7 @@ extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto;
extern const struct bpf_func_proto bpf_task_storage_get_proto;
extern const struct bpf_func_proto bpf_task_storage_delete_proto;
extern const struct bpf_func_proto bpf_for_each_map_elem_proto;
+extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto;
const struct bpf_func_proto *bpf_tracing_func_proto(
enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 068c23f278bc..47c4b21a51b6 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4721,6 +4721,13 @@ union bpf_attr {
* Execute bpf syscall with given arguments.
* Return
* A syscall result.
+ *
+ * long bpf_btf_find_by_name_kind(u32 btf_fd, char *name, u32 kind, u32 *attach_btf_obj_fd, int flags)
+ * Description
+ * Find given name with given type in BTF pointed to by btf_fd.
+ * If btf_fd is zero look for the name in vmlinux BTF and kernel module BTFs.
+ * Return
+ * Return btf_id and store module's BTF FD into attach_btf_obj_fd.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -4889,6 +4896,7 @@ union bpf_attr {
FN(check_mtu), \
FN(for_each_map_elem), \
FN(sys_bpf), \
+ FN(btf_find_by_name_kind), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index fbf6c06a9d62..2f474739d9d3 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6085,3 +6085,54 @@ struct module *btf_try_get_module(const struct btf *btf)
return res;
}
+
+BPF_CALL_5(bpf_btf_find_by_name_kind, int, btf_fd, char *, name, u32, kind, int *, attach_btf_obj_fd, int, flags)
+{
+ struct btf *btf;
+ int ret;
+
+ if (flags)
+ return -EINVAL;
+
+ if (btf_fd)
+ btf = btf_get_by_fd(btf_fd);
+ else
+ btf = bpf_get_btf_vmlinux();
+ if (IS_ERR(btf))
+ return PTR_ERR(btf);
+
+ *attach_btf_obj_fd = 0;
+ ret = btf_find_by_name_kind(btf, name, kind);
+ if (!btf_fd && ret < 0) {
+ struct btf *mod_btf;
+ int id = btf->id;
+
+ spin_lock_bh(&btf_idr_lock);
+ idr_for_each_entry_continue(&btf_idr, mod_btf, id) {
+ if (!btf_is_kernel(btf))
+ continue;
+ ret = btf_find_by_name_kind(mod_btf, name, kind);
+ if (ret > 0)
+ break;
+ }
+ if (mod_btf)
+ btf_get(mod_btf);
+ spin_unlock_bh(&btf_idr_lock);
+ if (mod_btf)
+ *attach_btf_obj_fd = __btf_new_fd(mod_btf);
+ }
+ if (btf_fd)
+ btf_put(btf);
+ return ret;
+}
+
+const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
+ .func = bpf_btf_find_by_name_kind,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_ANYTHING,
+ .arg2_type = ARG_ANYTHING,
+ .arg3_type = ARG_ANYTHING,
+ .arg4_type = ARG_PTR_TO_INT,
+ .arg5_type = ARG_ANYTHING,
+};
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 7b51d56e420b..6d4d9925c0ec 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4563,6 +4563,8 @@ syscall_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
switch (func_id) {
case BPF_FUNC_sys_bpf:
return &bpf_sys_bpf_proto;
+ case BPF_FUNC_btf_find_by_name_kind:
+ return &bpf_btf_find_by_name_kind_proto;
default:
return bpf_base_func_proto(func_id);
}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 068c23f278bc..47c4b21a51b6 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4721,6 +4721,13 @@ union bpf_attr {
* Execute bpf syscall with given arguments.
* Return
* A syscall result.
+ *
+ * long bpf_btf_find_by_name_kind(u32 btf_fd, char *name, u32 kind, u32 *attach_btf_obj_fd, int flags)
+ * Description
+ * Find given name with given type in BTF pointed to by btf_fd.
+ * If btf_fd is zero look for the name in vmlinux BTF and kernel module BTFs.
+ * Return
+ * Return btf_id and store module's BTF FD into attach_btf_obj_fd.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -4889,6 +4896,7 @@ union bpf_attr {
FN(check_mtu), \
FN(for_each_map_elem), \
FN(sys_bpf), \
+ FN(btf_find_by_name_kind), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
--
2.30.2
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