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 */ |
12 | extern char __weak __start_BTF[]; |
13 | extern char __weak __stop_BTF[]; |
14 | |
15 | static ssize_t |
16 | btf_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, __start_BTF + off, len); |
21 | return len; |
22 | } |
23 | |
24 | static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = { |
25 | .attr = { .name = "vmlinux" , .mode = 0444, }, |
26 | .read = btf_vmlinux_read, |
27 | }; |
28 | |
29 | struct kobject *btf_kobj; |
30 | |
31 | static int __init btf_vmlinux_init(void) |
32 | { |
33 | bin_attr_btf_vmlinux.size = __stop_BTF - __start_BTF; |
34 | |
35 | if (!__start_BTF || bin_attr_btf_vmlinux.size == 0) |
36 | return 0; |
37 | |
38 | btf_kobj = kobject_create_and_add(name: "btf" , parent: kernel_kobj); |
39 | if (!btf_kobj) |
40 | return -ENOMEM; |
41 | |
42 | return sysfs_create_bin_file(kobj: btf_kobj, attr: &bin_attr_btf_vmlinux); |
43 | } |
44 | |
45 | subsys_initcall(btf_vmlinux_init); |
46 | |