kheaders.c

 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
19asm (
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
29extern char kernel_headers_data[];
30extern char kernel_headers_data_end[];
31
32static struct bin_attribute kheaders_attr __ro_after_init =
33	__BIN_ATTR_SIMPLE_RO(kheaders.tar.xz, 0444);
34
35static int __init ikheaders_init(void)
36{
37	kheaders_attr.private = kernel_headers_data;
38	kheaders_attr.size = (kernel_headers_data_end -
39			      kernel_headers_data);
40	return sysfs_create_bin_file(kernel_kobj, &kheaders_attr);
41}
42
43static void __exit ikheaders_cleanup(void)
44{
45	sysfs_remove_bin_file(kernel_kobj, &kheaders_attr);
46}
47
48module_init(ikheaders_init);
49module_exit(ikheaders_cleanup);
50
51MODULE_LICENSE("GPL v2");
52MODULE_AUTHOR("Joel Fernandes");
53MODULE_DESCRIPTION("Echo the kernel header artifacts used to build the kernel");