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 __start_BTF[];
13 extern char __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 (bin_attr_btf_vmlinux.size == 0)
36 return 0;
37
38 btf_kobj = kobject_create_and_add("btf", kernel_kobj);
39 if (!btf_kobj)
40 return -ENOMEM;
41
42 return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux);
43 }
44
45 subsys_initcall(btf_vmlinux_init);
46
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