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 _binary__btf_vmlinux_bin_start[]; 13 extern char __weak _binary__btf_vmlinux_bin_end[]; 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, _binary__btf_vmlinux_bin_start + 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 static struct kobject *btf_kobj; 30 31 static int __init btf_vmlinux_init(void) 32 { 33 int err; 34 35 if (!_binary__btf_vmlinux_bin_start) 36 return 0; 37 38 btf_kobj = kobject_create_and_add("btf", kernel_kobj); 39 if (IS_ERR(btf_kobj)) { 40 err = PTR_ERR(btf_kobj); 41 btf_kobj = NULL; 42 return err; 43 } 44 45 bin_attr_btf_vmlinux.size = _binary__btf_vmlinux_bin_end - 46 _binary__btf_vmlinux_bin_start; 47 48 return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux); 49 } 50 51 subsys_initcall(btf_vmlinux_init); 52