1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Provide kernel headers useful to build tracing programs
4 * such as for running eBPF tracing tools.
5 *
6 * (Borrowed code from kernel/configs.c)
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/kobject.h>
12 #include <linux/init.h>
13
14 /*
15 * Define kernel_headers_data and kernel_headers_data_end, within which the
16 * compressed kernel headers are stored. The file is first compressed with xz.
17 */
18
19 asm (
20 " .pushsection .rodata, \"a\" \n"
21 " .global kernel_headers_data \n"
22 "kernel_headers_data: \n"
23 " .incbin \"kernel/kheaders_data.tar.xz\" \n"
24 " .global kernel_headers_data_end \n"
25 "kernel_headers_data_end: \n"
26 " .popsection \n"
27 );
28
29 extern char kernel_headers_data[];
30 extern char kernel_headers_data_end[];
31
32 static ssize_t
ikheaders_read(struct file * file,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t len)33 ikheaders_read(struct file *file, struct kobject *kobj,
34 struct bin_attribute *bin_attr,
35 char *buf, loff_t off, size_t len)
36 {
37 memcpy(buf, &kernel_headers_data[off], len);
38 return len;
39 }
40
41 static struct bin_attribute kheaders_attr __ro_after_init = {
42 .attr = {
43 .name = "kheaders.tar.xz",
44 .mode = 0444,
45 },
46 .read = &ikheaders_read,
47 };
48
ikheaders_init(void)49 static int __init ikheaders_init(void)
50 {
51 kheaders_attr.size = (kernel_headers_data_end -
52 kernel_headers_data);
53 return sysfs_create_bin_file(kernel_kobj, &kheaders_attr);
54 }
55
ikheaders_cleanup(void)56 static void __exit ikheaders_cleanup(void)
57 {
58 sysfs_remove_bin_file(kernel_kobj, &kheaders_attr);
59 }
60
61 module_init(ikheaders_init);
62 module_exit(ikheaders_cleanup);
63
64 MODULE_LICENSE("GPL v2");
65 MODULE_AUTHOR("Joel Fernandes");
66 MODULE_DESCRIPTION("Echo the kernel header artifacts used to build the kernel");
67
