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 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 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 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