1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Provide kernel BTF information for introspection and use by eBPF tools.
 4 */
 5#include <linux/kernel.h>
 6#include <linux/module.h>
 7#include <linux/kobject.h>
 8#include <linux/init.h>
 9#include <linux/sysfs.h>
10
11/* See scripts/link-vmlinux.sh, gen_btf() func for details */
12extern char __weak _binary__btf_vmlinux_bin_start[];
13extern char __weak _binary__btf_vmlinux_bin_end[];
14
15static ssize_t
16btf_vmlinux_read(struct file *file, struct kobject *kobj,
17		 struct bin_attribute *bin_attr,
18		 char *buf, loff_t off, size_t len)
19{
20	memcpy(buf, _binary__btf_vmlinux_bin_start + off, len);
21	return len;
22}
23
24static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = {
25	.attr = { .name = "vmlinux", .mode = 0444, },
26	.read = btf_vmlinux_read,
27};
28
29static struct kobject *btf_kobj;
30
31static int __init btf_vmlinux_init(void)
32{
33	if (!_binary__btf_vmlinux_bin_start)
34		return 0;
35
36	btf_kobj = kobject_create_and_add("btf", kernel_kobj);
37	if (!btf_kobj)
38		return -ENOMEM;
39
40	bin_attr_btf_vmlinux.size = _binary__btf_vmlinux_bin_end -
41				    _binary__btf_vmlinux_bin_start;
42
43	return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux);
44}
45
46subsys_initcall(btf_vmlinux_init);