linux-kernel - [RFC PATCH bpf-next 07/13] bpf: Add bpf helper to get bpf object id

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Date:   Sun, 26 Mar 2023 09:22:02 +0000
From:   Yafang Shao <laoar.shao@...il.com>
To:     ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
        kafai@...com, songliubraving@...com, yhs@...com,
        john.fastabend@...il.com, kpsingh@...nel.org, sdf@...gle.com,
        haoluo@...gle.com, jolsa@...nel.org
Cc:     bpf@...r.kernel.org, linux-kernel@...r.kernel.org,
        Yafang Shao <laoar.shao@...il.com>
Subject: [RFC PATCH bpf-next 07/13] bpf: Add bpf helper to get bpf object id

A new bpf helper is introduced to get bpf object id in a tracing bpf
prog.

Signed-off-by: Yafang Shao <laoar.shao@...il.com>
---
 include/linux/bpf.h            |  1 +
 include/uapi/linux/bpf.h       |  7 +++++++
 kernel/bpf/task_iter.c         | 12 ++++++++++++
 kernel/trace/bpf_trace.c       |  2 ++
 tools/include/uapi/linux/bpf.h |  7 +++++++
 5 files changed, 29 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 2d8f3f6..c94034a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2867,6 +2867,7 @@ static inline int bpf_fd_reuseport_array_update_elem(struct bpf_map *map,
 extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto;
 extern const struct bpf_func_proto bpf_cgrp_storage_get_proto;
 extern const struct bpf_func_proto bpf_cgrp_storage_delete_proto;
+extern const struct bpf_func_proto bpf_find_obj_id_proto;
 
 const struct bpf_func_proto *tracing_prog_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 e3d3b51..3009877 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5540,6 +5540,12 @@ struct bpf_stack_build_id {
  *		0 on success.
  *
  *		**-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * int bpf_find_obj_id(void *obj_id)
+ *	Description
+ *		Get bpf object id in current bpf namespace.
+ *	Return
+ *		bpf object id is returned on success.
  */
 #define ___BPF_FUNC_MAPPER(FN, ctx...)			\
 	FN(unspec, 0, ##ctx)				\
@@ -5754,6 +5760,7 @@ struct bpf_stack_build_id {
 	FN(user_ringbuf_drain, 209, ##ctx)		\
 	FN(cgrp_storage_get, 210, ##ctx)		\
 	FN(cgrp_storage_delete, 211, ##ctx)		\
+	FN(find_obj_id, 212, ##ctx)		\
 	/* */
 
 /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index c4ab9d6..a551743 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -8,6 +8,7 @@
 #include <linux/fdtable.h>
 #include <linux/filter.h>
 #include <linux/btf_ids.h>
+#include <linux/bpf_namespace.h>
 #include "mmap_unlock_work.h"
 
 static const char * const iter_task_type_names[] = {
@@ -823,6 +824,17 @@ static void bpf_iter_task_show_fdinfo(const struct bpf_iter_aux_info *aux, struc
 	.arg5_type	= ARG_ANYTHING,
 };
 
+BPF_CALL_1(bpf_find_obj_id, void *, obj_id)
+{
+	return bpf_obj_id_vnr(obj_id);
+}
+
+const struct bpf_func_proto bpf_find_obj_id_proto = {
+	.func		= bpf_find_obj_id,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+};
+
 DEFINE_PER_CPU(struct mmap_unlock_irq_work, mmap_unlock_work);
 
 static void do_mmap_read_unlock(struct irq_work *entry)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index bcf91bc..977bb61 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1510,6 +1510,8 @@ static int __init bpf_key_sig_kfuncs_init(void)
 		return &bpf_find_vma_proto;
 	case BPF_FUNC_trace_vprintk:
 		return bpf_get_trace_vprintk_proto();
+	case BPF_FUNC_find_obj_id:
+		return &bpf_find_obj_id_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 d6c5a02..8beacad 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5540,6 +5540,12 @@ struct bpf_stack_build_id {
  *		0 on success.
  *
  *		**-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * int bpf_find_obj_id(void *obj_id)
+ *	Description
+ *		Get bpf object id in current bpf namespace.
+ *	Return
+ *		bpf object id is returned on success.
  */
 #define ___BPF_FUNC_MAPPER(FN, ctx...)			\
 	FN(unspec, 0, ##ctx)				\
@@ -5754,6 +5760,7 @@ struct bpf_stack_build_id {
 	FN(user_ringbuf_drain, 209, ##ctx)		\
 	FN(cgrp_storage_get, 210, ##ctx)		\
 	FN(cgrp_storage_delete, 211, ##ctx)		\
+	FN(find_obj_id, 212, ##ctx)				\
 	/* */
 
 /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't
-- 
1.8.3.1